@article {pmid38492917, year = {2024}, author = {McGrane-Corrigan, B and Mason, O and de Andrade Moral, R}, title = {Inferring stochastic group interactions within structured populations via coupled autoregression.}, journal = {Journal of theoretical biology}, volume = {}, number = {}, pages = {111793}, doi = {10.1016/j.jtbi.2024.111793}, pmid = {38492917}, issn = {1095-8541}, abstract = {The internal behaviour of a population is an important feature to take account of when modelling its dynamics. In line with kin selection theory, many social species tend to cluster into distinct groups in order to enhance their overall population fitness. Temporal interactions between populations are often modelled using classical mathematical models, but these sometimes fail to delve deeper into the, often uncertain, relationships within populations. Here, we introduce a stochastic framework that aims to capture the interactions of animal groups and an auxiliary population over time. We demonstrate the model's capabilities, from a Bayesian perspective, through simulation studies and by fitting it to predator-prey count time series data. We then derive an approximation to the group correlation structure within such a population, while also taking account of the effect of the auxiliary population. We finally discuss how this approximation can lead to ecologically realistic interpretations in a predator-prey context. This approximation also serves as verification to whether the population in question satisfies our various assumptions. Our modelling approach will be useful for empiricists for monitoring groups within a conservation framework and also theoreticians wanting to quantify interactions, to study cooperation and other phenomena within social populations.}, } @article {pmid38477032, year = {2024}, author = {Fromhage, L and Jennions, MD and Myllymaa, L and Henshaw, JM}, title = {Fitness as the organismal performance measure guiding adaptive evolution.}, journal = {Evolution; international journal of organic evolution}, volume = {}, number = {}, pages = {}, doi = {10.1093/evolut/qpae043}, pmid = {38477032}, issn = {1558-5646}, abstract = {A long-standing problem in evolutionary theory is to clarify in what sense (if any) natural selection cumulatively improves the design of organisms. Various concepts, such as fitness and inclusive fitness, have been proposed to resolve this problem. In addition, there have been attempts to replace the original problem with more tractable questions such as whether a given gene or trait is favoured by selection. Here we ask what theoretical properties the concept fitness should possess to encapsulate the improvement criterion required to talk meaningfully about adaptive evolution. We argue that natural selection tends to shape phenotypes based on the causal properties of individuals, and that this tendency is therefore best captured by a fitness concept that focusses on these properties. We highlight a fitness concept which meets this role under broad conditions, but requires adjustments in our conceptual understanding of adaptive evolution. These adjustments combine elements of Dawkinsian gene selectionism and Egbert Leigh's "parliament of genes".}, } @article {pmid38462458, year = {2023}, author = {Libertini, G}, title = {Phenoptosis and the Various Types of Natural Selection.}, journal = {Biochemistry. Biokhimiia}, volume = {88}, number = {12}, pages = {2007-2022}, doi = {10.1134/S0006297923120052}, pmid = {38462458}, issn = {1608-3040}, abstract = {In the first description of evolution, the fundamental mechanism is the natural selection favoring the individuals best suited for survival and reproduction (selection at the individual level or classical Darwinian selection). However, this is a very reductive description of natural selection that does not consider or explain a long series of known phenomena, including those in which an individual sacrifices or jeopardizes his life on the basis of genetically determined mechanisms (i.e., phenoptosis). In fact, in addition to (i) selection at the individual level, it is essential to consider other types of natural selection such as those concerning: (ii) kin selection and some related forms of group selection; (iii) the interactions between the innumerable species that constitute a holobiont; (iv) the origin of the eukaryotic cell from prokaryotic organisms; (v) the origin of multicellular eukaryotic organisms from unicellular organisms; (vi) eusociality (e.g., in many species of ants, bees, termites); (vii) selection at the level of single genes, or groups of genes; (viii) the interactions between individuals (or more precisely their holobionts) of the innumerable species that make up an ecosystem. These forms of natural selection, which are all effects and not violations of the classical Darwinian selection, also show how concepts as life, species, individual, and phenoptosis are somewhat not entirely defined and somehow arbitrary. Furthermore, the idea of organisms selected on the basis of their survival and reproduction capabilities is intertwined with that of organisms also selected on the basis of their ability to cooperate and interact, even by losing their lives or their distinct identities.}, } @article {pmid38443305, year = {2024}, author = {Erler, S and Cotter, SC and Freitak, D and Koch, H and Palmer-Young, EC and de Roode, JC and Smilanich, AM and Lattorff, HMG}, title = {Insects' essential role in understanding and broadening animal medication.}, journal = {Trends in parasitology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.pt.2024.02.003}, pmid = {38443305}, issn = {1471-5007}, abstract = {Like humans, animals use plants and other materials as medication against parasites. Recent decades have shown that the study of insects can greatly advance our understanding of medication behaviors. The ease of rearing insects under laboratory conditions has enabled controlled experiments to test critical hypotheses, while their spectrum of reproductive strategies and living arrangements - ranging from solitary to eusocial communities - has revealed that medication behaviors can evolve to maximize inclusive fitness through both direct and indirect fitness benefits. Studying insects has also demonstrated in some cases that medication can act through modulation of the host's innate immune system and microbiome. We highlight outstanding questions, focusing on costs and benefits in the context of inclusive host fitness.}, } @article {pmid38420213, year = {2024}, author = {Kemp, JT and Kline, AG and Bettencourt, LMA}, title = {Information synergy maximizes the growth rate of heterogeneous groups.}, journal = {PNAS nexus}, volume = {3}, number = {2}, pages = {pgae072}, pmid = {38420213}, issn = {2752-6542}, abstract = {Collective action and group formation are fundamental behaviors among both organisms cooperating to maximize their fitness and people forming socioeconomic organizations. Researchers have extensively explored social interaction structures via game theory and homophilic linkages, such as kin selection and scalar stress, to understand emergent cooperation in complex systems. However, we still lack a general theory capable of predicting how agents benefit from heterogeneous preferences, joint information, or skill complementarities in statistical environments. Here, we derive general statistical dynamics for the origin of cooperation based on the management of resources and pooled information. Specifically, we show how groups that optimally combine complementary agent knowledge about resources in statistical environments maximize their growth rate. We show that these advantages are quantified by the information synergy embedded in the conditional probability of environmental states given agents' signals, such that groups with a greater diversity of signals maximize their collective information. It follows that, when constraints are placed on group formation, agents must intelligently select with whom they cooperate to maximize the synergy available to their own signal. Our results show how the general properties of information underlie the optimal collective formation and dynamics of groups of heterogeneous agents across social and biological phenomena.}, } @article {pmid38417560, year = {2024}, author = {Flatrès, A and Wild, G}, title = {Evolution of delayed dispersal with group size effect and population dynamics.}, journal = {Theoretical population biology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tpb.2024.02.007}, pmid = {38417560}, issn = {1096-0325}, abstract = {Individuals delay natal dispersal for many reasons. There may be no place to disperse to; immediate dispersal or reproduction may be too costly; immediate dispersal may mean that the individual and their relatives miss the benefits of group living. Understanding the factors that lead to the evolution of delayed dispersal is important because delayed dispersal sets the stage for complex social groups and social behavior. Here, we study the evolution of delayed dispersal when the quality of the local environment is improved by greater numbers of individuals (e.g., safety in numbers). We assume that individuals who delay natal dispersal also expect to delay personal reproduction. In addition, we assume that improved environmental quality benefits manifest as changes to fecundity and survival. We are interested in how do the changes in these life-history features affect delayed dispersal. We use a model that ties evolution to population dynamics. We also aim to understand the relationship between levels of delayed dispersal and the probability of establishing as an independent breeder (a population-level feature) in response to changes in life-history details. Our model emphasizes kin selection and considers a sexual organism, which allows us to study parent-offspring conflict over delayed dispersal. At evolutionary equilibrium, fecundity and survival benefits of group size or quality promote higher levels of delayed dispersal over a larger set of life histories with one exception. The exception is for benefits of increased group size or quality reaped by the individuals who delay dispersal. There, the increased benefit does not change the life histories supporting delay dispersal. Next, in contrast to previous predictions, we find that a low probability of establishing in a new location is not always associated with a higher incidence of delayed dispersal. Finally, we find that increased personal benefits of delayed dispersal exacerbate the conflict between parents and their offspring. We discuss our findings in relation to previous theoretical and empirical work, especially work related to cooperative breeding.}, } @article {pmid38412971, year = {2024}, author = {Dewar, AE and Belcher, LJ and Scott, TW and West, SA}, title = {Genes for cooperation are not more likely to be carried by plasmids.}, journal = {Proceedings. Biological sciences}, volume = {291}, number = {2017}, pages = {20232549}, doi = {10.1098/rspb.2023.2549}, pmid = {38412971}, issn = {1471-2954}, abstract = {Cooperation is prevalent across bacteria, but risks being exploited by non-cooperative cheats. Horizontal gene transfer, particularly via plasmids, has been suggested as a mechanism to stabilize cooperation. A key prediction of this hypothesis is that genes which are more likely to be transferred, such as those on plasmids, should be more likely to code for cooperative traits. Testing this prediction requires identifying all genes for cooperation in bacterial genomes. However, previous studies used a method which likely misses some of these genes for cooperation. To solve this, we used a new genomics tool, SOCfinder, which uses three distinct modules to identify all kinds of genes for cooperation. We compared where these genes were located across 4648 genomes from 146 bacterial species. In contrast to the prediction of the hypothesis, we found no evidence that plasmid genes are more likely to code for cooperative traits. Instead, we found the opposite-that genes for cooperation were more likely to be carried on chromosomes. Overall, the vast majority of genes for cooperation are not located on plasmids, suggesting that the more general mechanism of kin selection is sufficient to explain the prevalence of cooperation across bacteria.}, } @article {pmid38409256, year = {2024}, author = {Galdino, ACM and Vaillancourt, M and Celedonio, D and Huse, K and Doi, Y and Lee, JS and Jorth, P}, title = {Siderophores promote cooperative interspecies and intraspecies cross-protection against antibiotics in vitro.}, journal = {Nature microbiology}, volume = {}, number = {}, pages = {}, pmid = {38409256}, issn = {2058-5276}, support = {R21AI151362//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; R01AI14642//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; R01Hl136143//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; K22AI127473//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; R21AI151362//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; R01Hl136143//U.S. Department of Health & Human Services | National Institutes of Health (NIH)/ ; JORTH17F5//Cystic Fibrosis Foundation (CF Foundation)/ ; JORTH19P0//Cystic Fibrosis Foundation (CF Foundation)/ ; MILESI21F0//Cystic Fibrosis Foundation (CF Foundation)/ ; }, abstract = {The antibiotic cefiderocol hijacks iron transporters to facilitate its uptake and resists β-lactamase degradation. While effective, resistance has been detected clinically with unknown mechanisms. Here, using experimental evolution, we identified cefiderocol resistance mutations in Pseudomonas aeruginosa. Resistance was multifactorial in host-mimicking growth media, led to multidrug resistance and paid fitness costs in cefiderocol-free environments. However, kin selection drove some resistant populations to cross-protect susceptible individuals from killing by increasing pyoverdine secretion via a two-component sensor mutation. While pyochelin sensitized P. aeruginosa to cefiderocol killing, pyoverdine and the enterobacteria siderophore enterobactin displaced iron from cefiderocol, preventing uptake by susceptible cells. Among 113 P. aeruginosa intensive care unit clinical isolates, pyoverdine production directly correlated with cefiderocol tolerance, and high pyoverdine producing isolates cross-protected susceptible P. aeruginosa and other Gram-negative bacteria. These in vitro data show that antibiotic cross-protection can occur via degradation-independent mechanisms and siderophores can serve unexpected protective cooperative roles in polymicrobial communities.}, } @article {pmid38403933, year = {2024}, author = {Montazeaud, G and Keller, L}, title = {Greenbeards in plants?.}, journal = {The New phytologist}, volume = {}, number = {}, pages = {}, doi = {10.1111/nph.19599}, pmid = {38403933}, issn = {1469-8137}, support = {101030712//HORIZON EUROPE Marie Sklodowska-Curie Actions/ ; }, abstract = {Greenbeards are selfish genetic elements that make their bearers behave either altruistically towards individuals bearing similar greenbeard copies or harmfully towards individuals bearing different copies. They were first proposed by W.D. Hamilton over 50 yr ago, to illustrate that kin selection may operate at the level of single genes. Examples of greenbeards have now been reported in a wide range of taxa, but they remain undocumented in plants. In this paper, we discuss the theoretical likelihood of greenbeard existence in plants. We then question why the greenbeard concept has never been applied to plants and speculate on how hypothetical greenbeards could affect plant-plant interactions. Finally, we point to different research directions to improve our knowledge of greenbeards in plants.}, } @article {pmid38371869, year = {2024}, author = {Thomson, L and Espinosa, DP and Brandvain, Y and Van Cleve, J}, title = {Linked selection and the evolution of altruism in family-structured populations.}, journal = {Ecology and evolution}, volume = {14}, number = {2}, pages = {e10980}, pmid = {38371869}, issn = {2045-7758}, abstract = {Much research on the evolution of altruism via kin selection, group selection, and reciprocity focuses on the role of a single locus or quantitative trait. Very few studies have explored how linked selection, or selection at loci neighboring an altruism locus, impacts the evolution of altruism. While linked selection can decrease the efficacy of selection at neighboring loci, it might have other effects including promoting selection for altruism by increasing relatedness in regions of low recombination. Here, we used population genetic simulations to study how negative selection at linked loci, or background selection, affects the evolution of altruism. When altruism occurs between full siblings, we found that background selection interfered with selection on the altruistic allele, increasing its fixation probability when the altruistic allele was disfavored and reducing its fixation when the allele was favored. In other words, background selection has the same effect on altruistic genes in family-structured populations as it does on other, nonsocial, genes. This contrasts with prior research showing that linked selective sweeps can favor the evolution of cooperation, and we discuss possibilities for resolving these contrasting results.}, } @article {pmid38368855, year = {2024}, author = {Crespi, B}, title = {The roots of STEM: what are the evolutionary and neural bases of human mathematics and technology?.}, journal = {Brain, behavior and evolution}, volume = {}, number = {}, pages = {}, doi = {10.1159/000537908}, pmid = {38368855}, issn = {1421-9743}, abstract = {Introduction Neural exaptations represent descent via transitions to novel neural functions. A primary transition in human cognitive and neural evolution was from a predominantly socially-oriented primate brain to a brain that also instantiates and subserves science, and technology, and engineering, all of which depend on mathematics. Upon what neural substrates, and upon what evolved cognitive mechanisms, did human capacities for STEM, and especially its mathematical underpinnings, emerge? Previous theory focuses on roles for tools, language, and arithmetic in the cognitive origins of STEM, but none of these factors appears sufficient to support the transition. Methods In this article, I describe and evaluate a novel hypothesis for the neural origins and substrates of STEM-based cognition: that they are based in human kinship systems and human maximizing of inclusive fitness. Results The main evidence for this hypothesis is threefold. First, as demonstrated by anthropologists, human kinship systems exhibit complex mathematical and geometrical structures that function under sets of explicit rules, and such systems and rules pervade and organize all human cultures. Second, human kinship underlies the core algebraic mechanism of evolution, maximization of inclusive fitness, quantified as personal reproduction plus the sum of all effects on reproduction of others, each multiplied by their coefficient of relatedness to self. This is the only 'natural' equation expected to be represented in the human brain. Third, functional imaging studies show that kinship-related cognition activates frontal-parietal regions that are also activated in STEM-related tasks. In turn, the decision-making that integrates kinship levels with costs and benefits from alternative behaviors has recently been shown to recruit the lateral septum, a hub region that combines internal (from the prefrontal cortex, amygdala and other regions) and external information relevant to social behavior, using a dedicated subsystem of neurons specific to kinship. Conclusions Taken together, these lines of evidence suggest that kinship systems, and kin-associated behaviors, may represent exaptations for the origin of human STEM.}, } @article {pmid38358814, year = {2024}, author = {Kerr, NZ and Morris, WF and Walters, JR}, title = {Inclusive Fitness May Explain Some but Not All Benefits Derived from Helping Behavior in a Cooperatively Breeding Bird.}, journal = {The American naturalist}, volume = {203}, number = {3}, pages = {393-410}, doi = {10.1086/728670}, pmid = {38358814}, issn = {1537-5323}, abstract = {AbstractIn cooperative breeding systems, inclusive fitness theory predicts that nonbreeding helpers more closely related to the breeders should be more willing to provide costly alloparental care and thus have more impact on breeder fitness. In the red-cockaded woodpecker (Dryobates borealis), most helpers are the breeders' earlier offspring, but helpers do vary within groups in both relatedness to the breeders (some even being unrelated) and sex, and it can be difficult to parse their separate impacts on breeder fitness. Moreover, most support for inclusive fitness theory has been positive associations between relatedness and behavior rather than actual fitness consequences. We used functional linear models to evaluate the per capita effects of helpers of different relatedness on eight breeder fitness components measured for up to 41 years at three sites. In support of inclusive fitness theory, helpers more related to the breeding pair made greater contributions to six fitness components. However, male helpers made equal contributions to increasing prefledging survival regardless of relatedness. These findings suggest that both inclusive fitness benefits and other direct benefits may underlie helping behaviors in the red-cockaded woodpecker. Our results also demonstrate the application of an underused statistical approach to disentangle a complex ecological phenomenon.}, } @article {pmid38353866, year = {2024}, author = {Waynforth, D}, title = {Alloparental Support and Infant Psychomotor Developmental Delay.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {}, number = {}, pages = {}, pmid = {38353866}, issn = {1936-4776}, abstract = {Receiving social support from community and extended family has been typical for mothers with infants in human societies past and present. In non-industrialised contexts, infants of mothers with extended family support often have better health and higher survival through the vulnerable infant period, and hence shared infant care has a clear fitness benefit. However, there is scant evidence that these benefits continue in industrialised contexts. Better infant health and development with allocare support would indicate continued evolutionary selection for allocare. The research reported here used multiple logistic regression analysis to test whether a lack of family and other social support for mothers was associated with an increased risk of developmental delay in 9-month-old infants in the UK Millennium Cohort (analysis sample size, 15,696 infants). Extended family-based childcare during work hours and more maternal time spent with friends were the most influential kin and social support variables: infants of mothers with kin-based childcare versus all other childcare arrangements had a lower risk of developmental delay (OR = 0.61, 95% CIs: 0.46-0.82). Infants of mothers who spent no time with friends when compared with those who saw friends every day had double the odds of delay. Greater paternal involvement in infant care was associated with a lower odds of developmental delay. In conclusion, shared care of infants and social support for mothers may influence fitness-related traits in industrialised societies rather than being factors that influenced selection only in the past and in societies which retain close kin networks and a strong local community focus.}, } @article {pmid38350872, year = {2024}, author = {Araujo, NS and Ogihara, F and Martins, PM and Arias, MC}, title = {Insights from Melipona bicolor hybrid genome assembly: a stingless bee genome with chromosome-level scaffold.}, journal = {BMC genomics}, volume = {25}, number = {1}, pages = {171}, pmid = {38350872}, issn = {1471-2164}, support = {2019/23186-9; 2016/24669-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2019/23186-9; 2016/24669-5//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 40005980//Fonds De La Recherche Scientifique - FNRS/ ; 307356/2019-1//Conselho Nacional de Desenvolvimento Científico e Tecnológico/ ; }, abstract = {BACKGROUND: The highly eusocial stingless bees are crucial pollinators of native and agricultural ecosystems. Nevertheless, genomic studies within this bee tribe remain scarce. We present the genome assembly of the stingless bee Melipona bicolor. This bee is a remarkable exception to the typical single-queen colony structure, since in this species, multiple queens may coexist and share reproductive duties, resulting in genetically diverse colonies with weak kinship connections. As the only known genuinely polygynous bee, M. bicolor's genome provides a valuable resource for investigating sociality beyond kin selection.

RESULTS: The genome was assembled employing a hybrid approach combining short and long reads, resulting in 241 contigs spanning 259 Mb (N50 of 6.2 Mb and 97.5% complete BUSCOs). Comparative analyses shed light on some evolutionary aspects of stingless bee genomics, including multiple chromosomal rearrangements in Melipona. Additionally, we explored the evolution of venom genes in M. bicolor and other stingless bees, revealing that, apart from two genes, the conserved repertoire of venom components remains under purifying selection in this clade.

CONCLUSION: This study advances our understanding of stingless bee genomics, contributing to the conservation efforts of these vital pollinators and offering insights into the evolutionary mechanisms driving their unique adaptations.}, } @article {pmid38309717, year = {2024}, author = {Downing, PA}, title = {Michener's group-size paradox in cooperatively breeding birds.}, journal = {Journal of evolutionary biology}, volume = {}, number = {}, pages = {}, doi = {10.1093/jeb/voae008}, pmid = {38309717}, issn = {1420-9101}, support = {//University of Oulu/ ; 336449//Academy of Finland/ ; }, abstract = {According to Michener's paradox, most altruistic groups in nature should be small and large groups should not exist. This is because per capita productivity is thought to decrease as groups get larger, meaning that the share of indirect fitness available to each group member declines, which favours dispersal. The empirical evidence for a decrease in per capita productivity is contradictory, however, and limited to the social Hymenoptera. I report that per capita reproductive success decreased with increasing group size across 26 cooperatively breeding bird species. Small groups comprising two or three individuals were the most common (79% of 16,101 groups), and these had the highest per capita reproductive success. This close fit between per capita reproductive success and the distribution of group sizes in nature suggests that it may indeed be difficult for large groups to evolve through indirect fitness benefits alone.}, } @article {pmid38274864, year = {2024}, author = {Schroeder, JL and Worm, AJ and Sweet, AD and Rolland, V}, title = {Genomic data reveal unexpected relatedness between a brown female Eastern Bluebird and her brood.}, journal = {Ecology and evolution}, volume = {14}, number = {1}, pages = {e10851}, doi = {10.1002/ece3.10851}, pmid = {38274864}, issn = {2045-7758}, abstract = {Because plumage coloration is frequently involved in sexual selection, for both male and female mate choice, birds with aberrant plumage should have fewer mating opportunities and thus lower reproductive output. Here we report an Eastern Bluebird (Sialia sialis) female with a brown phenotype that raised a brood of four chicks to fledging. The brown female and her mate were only related to their social offspring to the second degree and one of the offspring was a half-sibling. We propose four family tree scenarios and discuss their implications (e.g., extra-pair paternity, conspecific brood parasitism). Regardless of the tree, the brown female was able to find a mate, which may have been facilitated by the bottleneck created by the severe snowstorms in February 2021.}, } @article {pmid38267842, year = {2024}, author = {Chapman, H and Hsiung, KC and Rawlinson, I and Galimov, ER and Gems, D}, title = {Colony level fitness analysis identifies a trade-off between population growth rate and dauer yield in Caenorhabditis elegans.}, journal = {BMC ecology and evolution}, volume = {24}, number = {1}, pages = {13}, pmid = {38267842}, issn = {2730-7182}, abstract = {BACKGROUND: In the evolution from unicellular to multicellular life forms, natural selection favored reduced cell proliferation and even programmed cell death if this increased organismal fitness. Could reduced individual fertility or even programmed organismal death similarly increase the fitness of colonies of closely-related metazoan organisms? This possibility is at least consistent with evolutionary theory, and has been supported by computer modelling. Caenorhabditis elegans has a boom and bust life history, where populations of nematodes that are sometimes near clonal subsist on and consume food patches, and then generate dauer larva dispersal propagules. A recent study of an in silico model of C. elegans predicted that one determinant of colony fitness (measured as dauer yield) is minimization of futile food consumption (i.e. that which does not contribute to dauer yield). One way to achieve this is to optimize colony population structure by adjustment of individual fertility.

RESULTS: Here we describe development of a C. elegans colony fitness assay, and its use to investigate the effect of altering population structure on colony fitness after population bust. Fitness metrics measured were speed of dauer production, and dauer yield, an indirect measure of efficiency of resource utilization (i.e. conversion of food into dauers). We find that with increasing founder number, speed of dauer production increases (due to earlier bust) but dauer yield rises and falls. In addition, some dauer recovery was detected soon after the post-colony bust peak of dauer yield, suggesting possible bet hedging among dauers.

CONCLUSIONS: These results suggest the presence of a fitness trade-off at colony level between speed and efficiency of resource utilization in C. elegans. They also provide indirect evidence that population structure is a determinant of colony level fitness, potentially by affecting level of futile food consumption.}, } @article {pmid38246487, year = {2024}, author = {Scott, TW}, title = {Crozier's paradox and kin recognition: insights from simplified models.}, journal = {Journal of theoretical biology}, volume = {}, number = {}, pages = {111735}, doi = {10.1016/j.jtbi.2024.111735}, pmid = {38246487}, issn = {1095-8541}, abstract = {Crozier's paradox suggests that genetic kin recognition will not be evolutionarily stable. The problem is that more common tags (markers) are more likely to be recognised and helped. This causes common tags to increase in frequency, eliminating the genetic variability that is required for genetic kin recognition. In recent years, theoretical models have resolved Crozier's paradox in different ways, but they are based on very complicated multi-locus population genetics. Consequently, it is hard to see exactly what is going on, and whether different theoretical resolutions of Crozier's paradox lead to different types of kin discrimination. I address this by making unrealistic simplifying assumptions to produce a more tractable and understandable model of Crozier's paradox. I use this to interpret a more complex multi-locus population genetic model where I have not made the same simplifying assumptions. I explain how Crozier's paradox can be resolved, and show that only one known theoretical resolution of Crozier's paradox - multiple social encounters - leads without restrictive assumptions to the type of highly cooperative and reliable form of kin discrimination that we observe in nature. More generally, I show how adopting a methodological approach where complex models are compared with simplified ones can lead to greater understanding and accessibility.}, } @article {pmid38232110, year = {2024}, author = {Komatsu, H and Kubota, H and Asano, K and Nagai, Y}, title = {Effect of information provision by familial nudging on attitudes toward offshore wind power.}, journal = {PloS one}, volume = {19}, number = {1}, pages = {e0297199}, doi = {10.1371/journal.pone.0297199}, pmid = {38232110}, issn = {1932-6203}, abstract = {Offshore wind power (OWP) is a promising way to achieve decarbonization and tackle global climate change, but acceptance by residents is an important issue for site location. Information provision could be a more cost-effective intervention than debates or subsidies, assuming that scientifically correct information alone is insufficient and information design to boost the message effects considering realistic human responses is necessary. Thus, we designed nudging messages to increase acceptance of OWP, using a message framework to moderate risk-averse attitudes by reminding readers of familial support based on insights from kin selection theory from evolutionary psychology. A randomized controlled trial based on an internet survey of more than 4000 responses from the general public was performed to investigate the message effects. The messages significantly moderated the risk-averse attitudes toward OWP by 0.228 on average on a five-point Likert scale, which meant that about 5 people out of 100 changed their attitudes to be safer by 1 point. This suggests that disseminating flyers using nudging messages might be an effective way to increase acceptance. We also extracted responses from those who mentioned fisheries in an open-ended question as an alternative to actual fishers. Responses from this segment were more complex and the message effects were limited compared with those who did not mention fisheries; although the attitudes toward OWP before receiving the messages were safer, reading descriptions for potential risks on fisheries may have unexpectedly led them to focus on the risks of which they were unaware at first. Because information provision based on nudging is effective but just one of a wide variety of political interventions available, practitioners should consider a combination of multiple options instead of using only nudging messages.}, } @article {pmid38214699, year = {2024}, author = {Pretelli, I and Crittenden, AN and Dounias, E and Friant, S and Koster, J and Kramer, KL and Mangola, SM and Saez, AM and Lew-Levy, S}, title = {Child and adolescent foraging: New directions in evolutionary research.}, journal = {Evolutionary anthropology}, volume = {}, number = {}, pages = {e22020}, doi = {10.1002/evan.22020}, pmid = {38214699}, issn = {1520-6505}, support = {ANR-17-EURE-0010//French National Research Agency (ANR)/ ; }, abstract = {Young children and adolescents in subsistence societies forage for a wide range of resources. They often target child-specific foods, they can be very successful foragers, and they share their produce widely within and outside of their nuclear family. At the same time, while foraging, they face risky situations and are exposed to diseases that can influence their immune development. However, children's foraging has largely been explained in light of their future (adult) behavior. Here, we reinterpret findings from human behavioral ecology, evolutionary medicine and cultural evolution to center foraging children's contributions to life history evolution, community resilience and immune development. We highlight the need to foreground immediate alongside delayed benefits and costs of foraging, including inclusive fitness benefits, when discussing children's food production from an evolutionary perspective. We conclude by recommending that researchers carefully consider children's social and ecological context, develop cross-cultural perspectives, and incorporate children's foraging into Indigenous sovereignty discourse.}, } @article {pmid38214204, year = {2024}, author = {Qian, C and Wen, C and Guo, X and Yang, X and Wen, X and Ma, T and Wang, C}, title = {Gregariousness in lepidopteran larvae.}, journal = {Insect science}, volume = {}, number = {}, pages = {}, doi = {10.1111/1744-7917.13312}, pmid = {38214204}, issn = {1744-7917}, support = {2022A1515010080//Guangdong Basic and Applied Basic Research Foundation/ ; }, abstract = {The gregarious lifestyle of lepidopteran larvae is diverse and shaped by a complex interplay of ecological and evolutionary factors. Our review showed that the larval-aggregation behavior has been reported in 23 lepidopteran families, indicating multiple evolution of this behavior. Some larvae live in sibling groups throughout all larval instars and even pupation stages, which may result from the kin-selection. In contrast, group fusion may occur among different sibling or foraging groups of larvae and form larger aggregates, and the gregariousness of these species might be driven by the group-selection. While group size and foraging patterns vary greatly across species, it is generally associated with improved larval survivorship and accelerated development. However, the advantages of group living, such as facilitating feeding activities, adjusting the temperature, and defending natural enemies, may diminish along with development, with strong intraspecific competition occurring at later instars, even when food is abundant. Therefore, the group sizes and fission-fusion dynamics of certain gregarious lepidopteran larvae may be a consequence of their cost-benefit balance depending on various biotic and abiotic factors. Trail and aggregation pheromones, silk trails, or body contact contribute to collective movement and group cohesion of gregarious lepidopteran larvae. However, frequent contact among group members may cause the horizontal transmission of pathogens and pesticides, which may bring an integrated pest management strategy controlling gregarious lepidopteran pests.}, } @article {pmid38207145, year = {2024}, author = {Schmid, M and Rueffler, C and Lehmann, L and Mullon, C}, title = {Resource Variation Within and Between Patches: Where Exploitation Competition, Local Adaptation, and Kin Selection Meet.}, journal = {The American naturalist}, volume = {203}, number = {1}, pages = {E19-E34}, doi = {10.1086/727483}, pmid = {38207145}, issn = {1537-5323}, abstract = {AbstractIn patch- or habitat-structured populations, different processes can favor adaptive polymorphism at different scales. While spatial heterogeneity can generate spatially disruptive selection favoring variation between patches, local competition can lead to locally disruptive selection promoting variation within patches. So far, almost all theory has studied these two processes in isolation. Here, we use mathematical modeling to investigate how resource variation within and between habitats influences the evolution of variation in a consumer population where individuals compete in finite patches connected by dispersal. We find that locally and spatially disruptive selection typically act in concert, favoring polymorphism under a wider range of conditions than when in isolation. But when patches are small and dispersal between them is low, kin competition inhibits the emergence of polymorphism, especially when the latter is driven by local competition for resources. We further use our model to clarify what comparisons between trait and neutral genetic differentiation (QST/FST comparisons) can tell about the nature of selection. Overall, our results help us understand the interaction between two major drivers of polymorphism: locally and spatially disruptive selection, and how this interaction is modulated by the unavoidable effects of kin selection under limited dispersal.}, } @article {pmid38161549, year = {2023}, author = {Hayman, J and Fortune, DW}, title = {Sexual Orientation in Twins: Evidence That Human Sexual Identity May Be Determined Five Days Following Fertilization.}, journal = {Cureus}, volume = {15}, number = {12}, pages = {e51346}, doi = {10.7759/cureus.51346}, pmid = {38161549}, issn = {2168-8184}, abstract = {Human same-sex sexual attraction has been recorded from the beginning of written history. It remains a controversial topic, but recent theories favor prenatal influences. A paradox is the occurrence of same-sex orientation in twins in that there is a higher level of concordance in monozygous twins compared to that in dizygous twins or non-twin siblings. If sexual orientation was entirely genetically determined monozygous twins would be expected to have identical sexual inclinations. Monozygous twins have twice the incidence of sexual concordance in comparison to dizygous twins but a third of these pairs have different sexual identities. An explanation for this disparity may lie in the time an embryo splits to form two separate fetuses. If splitting occurs early in twin development each twin may develop his or her own sexual identity; splitting occurring later results in twins that have the same sexual dispositions. A possible process for such determination may be in the mitochondria, with universal maternal inheritance of a proportion of normal functioning but alternate mitochondria. Variation in the distribution of these mitochondria in neural precursor cells becomes a mechanism for the development of intrinsic sexual orientation and for the spectrum of human sexual inclinations. The timing of embryonic splitting may be determined from the examination of fetal membranes, and the concept of early fetal sexual orientation is open to support or disproval.}, } @article {pmid38117204, year = {2023}, author = {Belcher, LJ and Dewar, AE and Hao, C and Katz, Z and Ghoul, M and West, SA}, title = {SOCfinder: a genomic tool for identifying social genes in bacteria.}, journal = {Microbial genomics}, volume = {9}, number = {12}, pages = {}, doi = {10.1099/mgen.0.001171}, pmid = {38117204}, issn = {2057-5858}, abstract = {Bacteria cooperate by working collaboratively to defend their colonies, share nutrients, and resist antibiotics. Nevertheless, our understanding of these remarkable behaviours primarily comes from studying a few well-characterized species. Consequently, there is a significant gap in our understanding of microbial social traits, particularly in natural environments. To address this gap, we can use bioinformatic tools to identify genes that control cooperative or otherwise social traits. Existing tools address this challenge through two approaches. One approach is to identify genes that encode extracellular proteins, which can provide benefits to neighbouring cells. An alternative approach is to predict gene function using annotation tools. However, these tools have several limitations. Not all extracellular proteins are cooperative, and not all cooperative behaviours are controlled by extracellular proteins. Furthermore, existing functional annotation methods frequently miss known cooperative genes. We introduce SOCfinder as a new tool to find bacterial genes that control cooperative or otherwise social traits. SOCfinder combines information from several methods, considering if a gene is likely to [1] code for an extracellular protein [2], have a cooperative functional annotation, or [3] be part of the biosynthesis of a cooperative secondary metabolite. We use data on two extensively-studied species (P. aeruginosa and B. subtilis) to show that SOCfinder is better at finding known cooperative genes than existing tools. We also use theory from population genetics to identify a signature of kin selection in SOCfinder cooperative genes, which is lacking in genes identified by existing tools. SOCfinder opens up a number of exciting directions for future research, and is available to download from https://github.com/lauriebelch/SOCfinder.}, } @article {pmid38018113, year = {2023}, author = {Rodrigues, AMM and Gardner, A}, title = {Transmission of social status drives cooperation and offspring philopatry.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2011}, pages = {20231314}, pmid = {38018113}, issn = {1471-2954}, mesh = {Animals ; Humans ; *Biological Evolution ; *Social Status ; Models, Theoretical ; Fertility ; }, abstract = {The evolution of cooperation depends on two crucial overarching factors: relatedness, which describes the extent to which the recipient shares genes in common with the actor; and quality, which describes the recipient's basic capacity to transmit genes into the future. While most research has focused on relatedness, there is a growing interest in understanding how quality modulates the evolution of cooperation. However, the impact of inheritance of quality on the evolution of cooperation remains largely unexplored, especially in spatially structured populations. Here, we develop a mathematical model to understand how inheritance of quality, in the form of social status, influences the evolution of helping and harming within social groups in a viscous-population setting. We find that: (1) status-reversal transmission, whereby parental and offspring status are negatively correlated, strongly inhibits the evolution of cooperation, with low-status individuals investing less in cooperation and high-status individuals being more prone to harm; (2) transmission of high status promotes offspring philopatry, with more cooperation being directed towards the higher-dispersal social class; and (3) fertility inequality and inter-generational status inheritance reduce within-group conflict. Overall, our study highlights the importance of considering different mechanisms of phenotypic inheritance, including social support, and their potential interactions in shaping animal societies.}, } @article {pmid38016596, year = {2023}, author = {Reynolds-Hogland, M and Brooks, C and Ramsey, AB and Hogland, JS and Pilgrim, KL and Engkjer, C and Ramsey, PW}, title = {Long-term video and genetic data yield insights into complex sociality of a solitary large carnivore.}, journal = {Behavioural processes}, volume = {214}, number = {}, pages = {104972}, doi = {10.1016/j.beproc.2023.104972}, pmid = {38016596}, issn = {1872-8308}, abstract = {American black bears (Ursus americanus) may be more social than currently understood. We used long-term video and genetic data to evaluate social interactions among wild, independent-aged black bear on a conservation property in western Montana, USA. We used multinomial logistic regression to evaluate predictions about male-male interactions within the context of individual fitness, female-female interactions within the context of inclusive fitness, and male-female interactions within the context of female counterstrategies to infanticide. Overall, our findings challenged the assumption that independent-aged bears interact only during the mating season or when concentrated feeding sites are present. We documented 169 interaction events by at least 66 bear pairs, 92 (54%) of which occurred outside of the peak mating season and in the absence of concentrated feeding sites. The probability that male-male pairs engaged in play and other non-agonistic behaviours was higher than that for female-female pairs. Conversely, the probability that female-female pairs engaged in chase behaviour was higher than that for male-male and male-female pairs. We documented evidence of female mate choice, female resource defense, sexually selected infanticide (SSI), and female counterstrategies to avoid SSI. Our findings improve our understanding of ursid ethology and underscore the complexity of ursid sociality.}, } @article {pmid37975504, year = {2023}, author = {Alizon, S}, title = {Multiple infection theory rather than 'socio-virology'? A commentary on Leeks et al. 2023.}, journal = {Journal of evolutionary biology}, volume = {36}, number = {11}, pages = {1571-1576}, doi = {10.1111/jeb.14245}, pmid = {37975504}, issn = {1420-9101}, mesh = {*Onions ; *Cooperative Behavior ; Genetic Fitness ; Biological Evolution ; }, } @article {pmid37969551, year = {2023}, author = {McCormack, JL and Arbuckle, K and Fullard, K and Amos, W and Nichols, HJ}, title = {Lack of intergenerational reproductive conflict, rather than lack of inclusive fitness benefits, explains absence of post-reproductive lifespan in long-finned pilot whales.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {34}, number = {6}, pages = {950-959}, pmid = {37969551}, issn = {1045-2249}, abstract = {Life-history theory suggests that individuals should reproduce until death, yet females of a small number of mammals live for a significant period after ceasing reproduction, a phenomenon known as post-reproductive lifespan. It is thought that the evolution of this trait is facilitated by increasing local relatedness throughout a female's lifetime. This allows older females to gain inclusive fitness through helping their offspring (known as a mother effect) and/or grandoffspring (known as a grandmother effect), rather than gaining direct fitness through reproducing. However, older females may only benefit from stopping reproducing when their direct offspring compete with those of their daughters. Here, we investigate whether a lack of post-reproductive lifespan in long-finned pilot whales (Globicephala melas) results from minimal benefits incurred from the presence of older females, or from a lack of costs resulting from mother-daughter co-reproduction. Using microsatellite data, we conducted parentage analysis on individuals from 25 pods and find that younger females were more likely to have offspring if their mother was present in their pod, indicating that mothers may assist inexperienced daughters to reproduce. However, we found no evidence of reproductive conflict between co-reproducing mothers and daughters, indicating that females may be able to reproduce into old age while simultaneously aiding their daughters in reproduction. This highlights the importance of reproductive conflict in the evolution of a post-reproductive lifespan and demonstrates that mother and grandmother effects alone do not result in the evolution of a post-reproductive lifespan.}, } @article {pmid37934441, year = {2023}, author = {Liechty, T and Woo, M and Rice, LA and Chiu, CY and Kirkpatrick, S and Hankins, K and Hedgspeth, E and Nichols, A and Porter, C and Smeltzer, M and Adamson, B}, title = {Community Partners' Perspectives on Partnering With an Academic Research Team to Promote Disability-inclusive Fitness Programming.}, journal = {Progress in community health partnerships : research, education, and action}, volume = {17}, number = {3}, pages = {429-437}, pmid = {37934441}, issn = {1557-055X}, mesh = {Humans ; *Community-Based Participatory Research ; *Disabled Persons ; Schools ; Communication ; Exercise ; }, abstract = {BACKGROUND: Community-based fitness programs can support public health by providing access to physical activity opportunities for a vulnerable population with significant barriers. Unfortunately, programs specifically designed for people with disabilities (PWD) and staff training to promote inclusion for PWD in general population programs is limited. The current study aimed to review an on-going partnership that had formed to address this need.

OBJECTIVES: The purpose of this study was to assess community partners' experiences with a community-academic partnership designed to implement a fitness program for people with multiple sclerosis and also to promote inclusion for PWD in community-based fitness programming.

METHODS: Semi-structured interviews were conducted with six community partners who had been engaged in a formal partnership with the academic institution for 2 or more years to understand partners' experiences and perspectives about the partnership. Interviews were audio/video recorded, transcribed verbatim, and analyzed thematically.

RESULTS: Participants described their experiences as falling into four main areas. Pre-partnership experiences (or lack thereof) shaped participants views on entering into academic partnerships. Communication and planning for mutual benefit were key to getting the partnership started. Partners identified challenges and factors for success while they were in the thick of partnership activities. Finally, evaluation allowed for assessment and improvement of the partnership itself and its ultimate goals.

CONCLUSIONS: Findings suggest that academic-community partnerships can be ideal for promoting inclusion for PWD and highlight insights that can be used in the development of future partnerships.}, } @article {pmid37926425, year = {2024}, author = {Gardner, A}, title = {A geometric approach to the evolution of altruism.}, journal = {Journal of theoretical biology}, volume = {576}, number = {}, pages = {111653}, doi = {10.1016/j.jtbi.2023.111653}, pmid = {37926425}, issn = {1095-8541}, mesh = {*Altruism ; *Selection, Genetic ; Biological Evolution ; Mathematics ; Probability ; }, abstract = {Fisher's geometric model provides a powerful tool for making predictions about key properties of Darwinian adaptation. Here, I apply the geometric model to predict differences between the evolution of altruistic versus nonsocial phenotypes. I recover Kimura's prediction that probability of fixation is greater for mutations of intermediate size, but I find that the effect size that maximises probability of fixation is relatively small in the context of altruism and relatively large in the context of nonsocial phenotypes, and that the overall probability of fixation is lower for altruism and is higher for nonsocial phenotypes. Accordingly, the first selective substitution is expected to be smaller, and to take longer, in the context of the evolution of altruism. These results strengthen the justification for employing streamlined social evolutionary methodologies that assume adaptations are underpinned by many genes of small effect.}, } @article {pmid37867189, year = {2023}, author = {Szilágyi, A and Czárán, T and Santos, M and Szathmáry, E}, title = {Directional selection coupled with kin selection favors the establishment of senescence.}, journal = {BMC biology}, volume = {21}, number = {1}, pages = {230}, pmid = {37867189}, issn = {1741-7007}, mesh = {Humans ; *Aging/genetics ; *Longevity ; Mutation ; Reproduction ; Biological Evolution ; Selection, Genetic ; }, abstract = {BACKGROUND: Conventional wisdom in evolutionary theory considers aging as a non-selected byproduct of natural selection. Based on this, conviction aging was regarded as an inevitable phenomenon. It was also thought that in the wild organisms tend to die from diseases, predation and other accidents before they could reach the time when senescence takes its course. Evidence has accumulated, however, that aging is not inevitable and there are organisms that show negative aging even. Furthermore, old age does play a role in the deaths of many different organisms in the wild also. The hypothesis of programmed aging posits that a limited lifespan can evolve as an adaptation (i.e., positively selected for) in its own right, partly because it can enhance evolvability by eliminating "outdated" genotypes. A major shortcoming of this idea is that non-aging sexual individuals that fail to pay the demographic cost of aging would be able to steal good genes by recombination from aging ones.

RESULTS: Here, we show by a spatially explicit, individual-based simulation model that aging can positively be selected for if a sufficient degree of kin selection complements directional selection. Under such conditions, senescence enhances evolvability because the rate of aging and the rate of recombination play complementary roles. The selected aging rate is highest at zero recombination (clonal reproduction). In our model, increasing extrinsic mortality favors evolved aging by making up free space, thereby decreasing competition and increasing drift, even when selection is stabilizing and the level of aging is set by mutation-selection balance. Importantly, higher extrinsic mortality is not a substitute for evolved aging under directional selection either. Reduction of relatedness decreases the evolved level of aging; chance relatedness favors non-aging genotypes. The applicability of our results depends on empirical values of directional and kin selection in the wild.

CONCLUSIONS: We found that aging can positively be selected for in a spatially explicit population model when sufficiently strong directional and kin selection prevail, even if reproduction is sexual. The view that there is a conceptual link between giving up clonal reproduction and evolving an aging genotype is supported by computational results.}, } @article {pmid37829498, year = {2023}, author = {Belcher, LJ and Dewar, AE and Hao, C and Ghoul, M and West, SA}, title = {Signatures of kin selection in a natural population of the bacteria Bacillus subtilis.}, journal = {Evolution letters}, volume = {7}, number = {5}, pages = {315-330}, pmid = {37829498}, issn = {2056-3744}, abstract = {Laboratory experiments have suggested that bacteria perform a range of cooperative behaviors, which are favored because they are directed toward relatives (kin selection). However, there is a lack of evidence for cooperation and kin selection in natural bacterial populations. Molecular population genetics offers a promising method to study natural populations because the theory predicts that kin selection will lead to relaxed selection, which will result in increased polymorphism and divergence at cooperative genes. Examining a natural population of Bacillus subtilis, we found consistent evidence that putatively cooperative traits have higher polymorphism and greater divergence than putatively private traits expressed at the same rate. In addition, we were able to eliminate alternative explanations for these patterns and found more deleterious mutations in genes controlling putatively cooperative traits. Overall, our results suggest that cooperation is favored by kin selection, with an average relatedness of r = .79 between interacting individuals.}, } @article {pmid37817595, year = {2023}, author = {Bourke, AFG}, title = {Conflict and conflict resolution in the major transitions.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2008}, pages = {20231420}, pmid = {37817595}, issn = {1471-2954}, mesh = {Humans ; *Negotiating ; *Biological Evolution ; Sexual Behavior ; }, abstract = {Conflict and conflict resolution have been argued to be fundamental to the major transitions in evolution. These were key events in life's history in which previously independently living individuals cooperatively formed a higher-level individual, such as a multicellular organism or eusocial colony. Conflict has its central role because, to proceed stably, the evolution of individuality in each major transition required within-individual conflict to be held in check. This review revisits the role of conflict and conflict resolution in the major transitions, addressing recent work arguing for a minor role. Inclusive fitness logic suggests that differences between the kin structures of clones and sexual families support the absence of conflict at the origin of multicellularity but, by contrast, suggest that key conflicts existed at the origin of eusociality. A principal example is conflict over replacing the founding queen (queen replacement). Following the origin of each transition, conflict remained important, because within-individual conflict potentially disrupts the attainment of maximal individuality (organismality) in the system. The conclusion is that conflict remains central to understanding the major transitions, essentially because conflict arises from differences in inclusive fitness optima while conflict resolution can help the system attain a high degree of coincidence of inclusive fitness interests.}, } @article {pmid37788701, year = {2023}, author = {Scott, TW and Wild, G}, title = {How to make an inclusive-fitness model.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2008}, pages = {20231310}, pmid = {37788701}, issn = {1471-2954}, mesh = {Humans ; *Biological Evolution ; *Social Behavior ; Altruism ; Reproduction ; Sex Ratio ; Selection, Genetic ; Genetic Fitness ; }, abstract = {Social behaviours are typically modelled using neighbour-modulated fitness, which focuses on individuals having their fitness altered by neighbours. However, these models are either interpreted using inclusive fitness, which focuses on individuals altering the fitness of neighbours, or not interpreted at all. This disconnect leads to interpretational mistakes and obscures the adaptive significance of behaviour. We bridge this gap by presenting a systematic methodology for constructing inclusive-fitness models. We find a behaviour's 'inclusive-fitness effect' by summing primary and secondary deviations in reproductive value. Primary deviations are the immediate result of a social interaction; for example, the cost and benefit of an altruistic act. Secondary deviations are compensatory effects that arise because the total reproductive value of the population is fixed; for example, the increased competition that follows an altruistic act. Compared to neighbour-modulated fitness methodologies, our approach is often simpler and reveals the model's inclusive-fitness narrative clearly. We implement our methodology first in a homogeneous population, with supplementary examples of help under synergy, help in a viscous population and Creel's paradox. We then implement our methodology in a class-structured population, where the advantages of our approach are most evident, with supplementary examples of altruism between age classes, and sex-ratio evolution.}, } @article {pmid37766488, year = {2023}, author = {Li, Z and Chen, S and Wei, S and Komdeur, J and Lu, X}, title = {Should sons breed independently or help? Local relatedness matters.}, journal = {The Journal of animal ecology}, volume = {92}, number = {11}, pages = {2189-2200}, doi = {10.1111/1365-2656.14005}, pmid = {37766488}, issn = {1365-2656}, mesh = {Humans ; Male ; Animals ; *Nuclear Family ; Social Behavior ; *Passeriformes/genetics ; Breeding ; Reproduction ; Cooperative Behavior ; }, abstract = {In cooperatively breeding birds, why do some individuals breed independently but others have to help at home? This question has been rarely addressed despite its fundamental importance for understanding the evolution of social cooperation. We address it using 15 years of data from Tibetan ground tits Pseudopodoces humilis where helpers consist of younger males. Since whether younger males successfully breed depends critically on their chances to occupy territories nearby home, our analytic strategy is to identify the determinants of individual differences in gaining territory ownership among these ready-to-breed males. Across widowed, last-year helper and yearling males, an age advantage was evident in inheriting resident territories, occupying adjacent vacancies and budding off part of adjacent territories, which left some last-year helpers and most yearling males to take the latter two routes. These males were more likely to acquire a territory if they were genetically related to the previous or current territory owners; otherwise they remained on natal territories as helpers. The relatedness effect can arise from the prior residence advantage established in the preceding winter when younger males followed their parents to perform kin-directed off-territory forays. Our research highlights the key role of local kinship in determining younger males' territory acquisition and thus their fate in terms of independent reproduction versus help. This finding provides insight into the formation of kin-based, facultative cooperative societies prevailing among vertebrates.}, } @article {pmid37746895, year = {2023}, author = {Bresnahan, ST and Galbraith, D and Ma, R and Anton, K and Rangel, J and Grozinger, CM}, title = {Beyond conflict: Kinship theory of intragenomic conflict predicts individual variation in altruistic behaviour.}, journal = {Molecular ecology}, volume = {32}, number = {21}, pages = {5823-5837}, doi = {10.1111/mec.17145}, pmid = {37746895}, issn = {1365-294X}, support = {DGE1255832//Division of Graduate Education/ ; MCB-0950896//Division of Molecular and Cellular Biosciences/ ; PEN04716//National Institute of Food and Agriculture/ ; }, abstract = {Behavioural variation is essential for animals to adapt to different social and environmental conditions. The Kinship Theory of Intragenomic Conflict (KTIC) predicts that parent-specific alleles can support different behavioural strategies to maximize allele fitness. Previous studies, including in honey bees (Apis mellifera), supported predictions of the KTIC for parent-specific alleles to promote selfish behaviour. Here, we test the KTIC prediction that for altruism-promoting genes (i.e. those that promote behaviours that support the reproductive fitness of kin), the allele with the higher altruism optimum should be selected to be expressed while the other is silenced. In honey bee colonies, workers act altruistically when tending to the queen by performing a 'retinue' behaviour, distributing the queen's mandibular pheromone (QMP) throughout the hive. Workers exposed to QMP do not activate their ovaries, ensuring they care for the queen's brood instead of competing to lay unfertilized eggs. Due to the haplodiploid genetics of honey bees, the KTIC predicts that response to QMP is favoured by the maternal genome. We report evidence for parent-of-origin effects on the retinue response behaviour, ovarian development and gene expression in brains of worker honey bees exposed to QMP, consistent with the KTIC. Additionally, we show enrichment for genes with parent-of-origin expression bias within gene regulatory networks associated with variation in bees' response to QMP. Our study demonstrates that intragenomic conflict can shape diverse social behaviours and influence expression patterns of single genes as well as gene networks.}, } @article {pmid37700652, year = {2023}, author = {Twyman, KZ and Gardner, A}, title = {Kin selection of time travel: the social evolutionary causes and consequences of dormancy.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2006}, pages = {20231247}, pmid = {37700652}, issn = {1471-2954}, mesh = {Humans ; *Social Evolution ; *Altruism ; Travel ; }, abstract = {A basic mechanism of kin selection is limited dispersal, whereby individuals remain close to their place of origin such that even indiscriminate social interaction tends to modify the fitness of genealogical kin. Accordingly, the causes and consequences of dispersal have received an enormous amount of attention in the social evolution literature. This work has focused on dispersal of individuals in space, yet similar logic should apply to dispersal of individuals in time (e.g. dormancy). We investigate how kin selection drives the evolution of dormancy and how dormancy modulates the evolution of altruism. We recover dormancy analogues of key results that have previously been given for dispersal, showing that: (1) kin selection favours dormancy as a means of relaxing competition between relatives; (2) when individuals may adjust their dormancy behaviour to local density, they are favoured to do so, resulting in greater dormancy in high-density neighbourhoods and a concomitant 'constant non-dormant principle'; (3) when dormancy is constrained to be independent of density, there is no relationship between the rate of dormancy and the evolutionary potential for altruism; and (4) when dormancy is able to evolve in a density-dependent manner, a greater potential for altruism is expected in populations with lower dormancy.}, } @article {pmid37670147, year = {2023}, author = {Roper, M and Green, JP and Salguero-Gómez, R and Bonsall, MB}, title = {Inclusive fitness forces of selection in an age-structured population.}, journal = {Communications biology}, volume = {6}, number = {1}, pages = {909}, pmid = {37670147}, issn = {2399-3642}, support = {BB/M011224/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Humans ; *Exercise ; Population Dynamics ; *Population Growth ; Reproduction ; }, abstract = {Hamilton's force of selection acting against age-specific mortality is constant and maximal prior to the age of first reproduction, before declining to zero at the age of last reproduction. The force of selection acting on age-specific reproduction declines monotonically from birth in a growing or stationary population. Central to these results is the assumption that individuals do not interact with one another. This assumption is violated in social organisms, where an individual's survival and/or reproduction may shape the inclusive fitness of other group members. Yet, it remains unclear how the forces of selection might be modified when inclusive fitness, rather than population growth rate, is considered the appropriate metric for fitness. Here, we derive such inclusive fitness forces of selection, and show that selection on age-specific survival is not always constant before maturity, and can remain above zero in post-reproductive age classes. We also show how the force of selection on age-specific reproduction does not always decline monotonically from birth, but instead depends on the balance of costs and benefits of increasing reproduction to both direct and indirect fitness. Our theoretical framework provides an opportunity to expand our understanding of senescence across social species.}, } @article {pmid37667646, year = {2023}, author = {Nonacs, P}, title = {Why do Hymenopteran workers drift to non-natal groups? Generalized reciprocity and the maximization of group and parental success.}, journal = {Journal of evolutionary biology}, volume = {36}, number = {10}, pages = {1365-1374}, doi = {10.1111/jeb.14215}, pmid = {37667646}, issn = {1420-9101}, mesh = {Humans ; Animals ; *Hymenoptera/genetics ; Biological Evolution ; Hybrid Vigor ; Social Behavior ; }, abstract = {Eusocial Hymenoptera are often characterized by having facultatively or obligately sterile worker castes. However, findings across an increasing number of species are that some workers are non-natal-they have 'drifted' away from where they were born and raised. Moreover, drifters are often indistinguishable from natal workers in the work and benefits provided to joined groups. This seems an evolutionary paradox of providing benefits to potentially unrelated individuals over close kin. Rather than being mistakes, drifting is proposed to be adaptive if joiners either gain inclusive fitness by preferentially moving to other kin groups or through generalized reciprocity in which exchanging workers across groups raises group-level genetic diversity and creates social heterosis. It is unclear, however, if reciprocity is unlikely because of a susceptibility to cheating. In resolving this question, a series of evolutionary simulations show: (1) Reciprocity can persist under a range of genetic assumptions and scenarios of cheating, (2) cheating almost always evolves, but can be expressed in a variety of ways that are not always predictable, (3) the inclusive fitness hypothesis is equally or more susceptible to cheating. Moreover, existing data in Hymenoptera (although not extensive) are more consistent with generalized reciprocity. This supports a hypothesis that drifting, as a phenomenon, may more often reflect maximization of group and parental fitness rather than fitness gains for the individual drifters.}, } @article {pmid37642131, year = {2023}, author = {Walasek, L and Brown, GDA}, title = {Incomparability and Incommensurability in Choice: No Common Currency of Value?.}, journal = {Perspectives on psychological science : a journal of the Association for Psychological Science}, volume = {}, number = {}, pages = {17456916231192828}, doi = {10.1177/17456916231192828}, pmid = {37642131}, issn = {1745-6924}, abstract = {Models of decision-making typically assume the existence of some common currency of value, such as utility, happiness, or inclusive fitness. This common currency is taken to allow comparison of options and to underpin everyday choice. Here we suggest instead that there is no universal value scale, that incommensurable values pervade everyday choice, and hence that most existing models of decision-making in both economics and psychology are fundamentally limited. We propose that choice objects can be compared only with reference to specific but nonuniversal "covering values." These covering values may reflect decision-makers' goals, motivations, or current states. A complete model of choice must accommodate the range of possible covering values. We show that abandoning the common-currency assumption in models of judgment and decision-making necessitates rank-based and "simple heuristics" models that contrast radically with conventional utility-based approaches. We note that if there is no universal value scale, then Arrow's impossibility theorem places severe bounds on the rationality of individual decision-making and hence that there is a deep link between the incommensurability of value, inconsistencies in human decision-making, and rank-based coding of value. More generally, incommensurability raises the question of whether it will ever be possible to develop single-quantity-maximizing models of decision-making.}, } @article {pmid37637319, year = {2023}, author = {Zhang, K and Zhang, ZQ}, title = {A thelytokous predatory mite is more cannibalistic towards distant kin.}, journal = {Current zoology}, volume = {69}, number = {5}, pages = {578-584}, pmid = {37637319}, issn = {1674-5507}, abstract = {Kin recognition has been widely observed in various taxa. Cannibalism avoidance may be a strong driver for the evolution of kin recognition, as it may avoid a reduction in inclusive fitness. Kin recognition has recently been observed in a generalist phytoseiid, Amblyseius herbicolus (Acari: Phytoseiidae). This study experimentally examined the degree of relatedness needed between prey larvae and cannibal adults of A. herbicolus for the occurrence of kin discrimination. The adults were individually placed in enclosed arenas with two prey, a daughter and a more distant related larva, to observe their cannibalizing choice. The adults of A. herbicolus did not discriminate between close relatives (daughter versus niece) but preferably cannibalized more distant kin (i.e., first and second cousins once removed). Phenotype matching and familiarization seem prominent as recognition mechanisms used by A. herbicolus adults. The effect of learning on kin recognition through prior contact in A. herbicolus requires further investigation. Studies on other adaptive functions of kin recognition of A. herbicolus, such as cooperation and parental care, may provide meaningful insights.}, } @article {pmid37608718, year = {2023}, author = {Úbeda, F and Wild, G}, title = {Microchimerism as a source of information on future pregnancies.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2005}, pages = {20231142}, pmid = {37608718}, issn = {1471-2954}, mesh = {Pregnancy ; Humans ; Female ; *Chimerism ; *Information Sources ; Mothers ; Pelvis ; Placenta ; }, abstract = {Small numbers of fetal cells cross the placenta during pregnancy turning mothers into microchimeras. Fetal cells from all previous pregnancies accumulate forming the mother's fetal microchiome. What is significant about microchimeric cells is that they have been linked to health problems including reproductive and autoimmune diseases. Three decades after the discovery of fetal microchimerism, the function of these cells remains a mystery. Here, we contend that the role of microchimeric cells is to inform the fetus about the likelihood that its genes are present in future pregnancies. We argue that, when genes are more likely than average to be in future maternal siblings, fetuses will send a fixed number of cells that will not elicit a maternal immune response against them. However, when genes are less likely to be in future maternal siblings, fetuses will send an ever-increasing number of cells that will elicit an ever-stronger maternal immune response. Our work can explain the observed clinical association between microchimeric cells and pre-eclampsia. However, our work predicts that this association should be stronger in women with a genetically diverse microchiome. If supported by medical tests, our work would allow establishing the likelihood of pregnancy or autoimmune problems advising medical interventions.}, } @article {pmid37588900, year = {2022}, author = {He, QQ and Rui, JW and Zhang, L and Tao, Y and Wu, JJ and Mace, R and Ji, T}, title = {Communal breeding by women is associated with lower investment from husbands.}, journal = {Evolutionary human sciences}, volume = {4}, number = {}, pages = {e50}, pmid = {37588900}, issn = {2513-843X}, abstract = {According to Hamilton's rule, matrilineal-biased investment restrains men in matrilineal societies from maximising their inclusive fitness (the 'matrilineal puzzle'). A recent hypothesis argues that when women breed communally and share household resources, a man should help his sisters' household, rather than his wife's household, as investment to the later but not the former would be diluted by other unrelated members (Wu et al., 2013). According to this hypothesis, a man is less likely to help on his wife's farm when there are more women reproducing in the wife's household, because on average he would be less related to his wife's household. We used a farm-work observational dataset, that we collected in the matrilineal Mosuo in southwest China, to test this hypothesis. As predicted, high levels of communal breeding by women in his wife's households do predict less effort spent by men on their wife's farm, and communal breeding in men's natal households do not affect whether men help on their natal farms. Thus, communal breeding by women dilutes the inclusive fitness benefits men receive from investment to their wife and children, and may drive the evolution of matrilineal-biased investment by men. These results can help solve the 'matrilineal puzzle'.}, } @article {pmid37528574, year = {2023}, author = {Couto, A and Marty, S and Dawson, EH and d'Ettorre, P and Sandoz, JC and Montgomery, SH}, title = {Evolution of the neuronal substrate for kin recognition in social Hymenoptera.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {98}, number = {6}, pages = {2226-2242}, doi = {10.1111/brv.13003}, pmid = {37528574}, issn = {1469-185X}, mesh = {Bees ; Animals ; *Wasps/physiology ; Social Behavior ; *Ants ; Reproduction/physiology ; Selection, Genetic ; Biological Evolution ; Mammals ; }, abstract = {In evolutionary terms, life is about reproduction. Yet, in some species, individuals forgo their own reproduction to support the reproductive efforts of others. Social insect colonies for example, can contain up to a million workers that actively cooperate in tasks such as foraging, brood care and nest defence, but do not produce offspring. In such societies the division of labour is pronounced, and reproduction is restricted to just one or a few individuals, most notably the queen(s). This extreme eusocial organisation exists in only a few mammals, crustaceans and insects, but strikingly, it evolved independently up to nine times in the order Hymenoptera (including ants, bees and wasps). Transitions from a solitary lifestyle to an organised society can occur through natural selection when helpers obtain a fitness benefit from cooperating with kin, owing to the indirect transmission of genes through siblings. However, this process, called kin selection, is vulnerable to parasitism and opportunistic behaviours from unrelated individuals. An ability to distinguish kin from non-kin, and to respond accordingly, could therefore critically facilitate the evolution of eusociality and the maintenance of non-reproductive workers. The question of how the hymenopteran brain has adapted to support this function is therefore a fundamental issue in evolutionary neuroethology. Early neuroanatomical investigations proposed that social Hymenoptera have expanded integrative brain areas due to selection for increased cognitive capabilities in the context of processing social information. Later studies challenged this assumption and instead pointed to an intimate link between higher social organisation and the existence of developed sensory structures involved in recognition and communication. In particular, chemical signalling of social identity, known to be mediated through cuticular hydrocarbons (CHCs), may have evolved hand in hand with a specialised chemosensory system in Hymenoptera. Here, we compile the current knowledge on this recognition system, from emitted identity signals, to the molecular and neuronal basis of chemical detection, with particular emphasis on its evolutionary history. Finally, we ask whether the evolution of social behaviour in Hymenoptera could have driven the expansion of their complex olfactory system, or whether the early origin and conservation of an olfactory subsystem dedicated to social recognition could explain the abundance of eusocial species in this insect order. Answering this question will require further comparative studies to provide a comprehensive view on lineage-specific adaptations in the olfactory pathway of Hymenoptera.}, } @article {pmid37492150, year = {2023}, author = {Capp, JP and Thomas, F and Marusyk, A and M Dujon, A and Tissot, S and Gatenby, R and Roche, B and Ujvari, B and DeGregori, J and Brown, JS and Nedelcu, AM}, title = {The paradox of cooperation among selfish cancer cells.}, journal = {Evolutionary applications}, volume = {16}, number = {7}, pages = {1239-1256}, pmid = {37492150}, issn = {1752-4571}, support = {U01 CA271830/CA/NCI NIH HHS/United States ; }, abstract = {It is traditionally assumed that during cancer development, tumor cells abort their initially cooperative behavior (i.e., cheat) in favor of evolutionary strategies designed solely to enhance their own fitness (i.e., a "selfish" life style) at the expense of that of the multicellular organism. However, the growth and progress of solid tumors can also involve cooperation among these presumed selfish cells (which, by definition, should be noncooperative) and with stromal cells. The ultimate and proximate reasons behind this paradox are not fully understood. Here, in the light of current theories on the evolution of cooperation, we discuss the possible evolutionary mechanisms that could explain the apparent cooperative behaviors among selfish malignant cells. In addition to the most classical explanations for cooperation in cancer and in general (by-product mutualism, kin selection, direct reciprocity, indirect reciprocity, network reciprocity, group selection), we propose the idea that "greenbeard" effects are relevant to explaining some cooperative behaviors in cancer. Also, we discuss the possibility that malignant cooperative cells express or co-opt cooperative traits normally expressed by healthy cells. We provide examples where considerations of these processes could help understand tumorigenesis and metastasis and argue that this framework provides novel insights into cancer biology and potential strategies for cancer prevention and treatment.}, } @article {pmid37476514, year = {2023}, author = {Catitti, B and Kormann, UG and van Bergen, VS and Grüebler, MU}, title = {Turning tables: food availability shapes dynamic aggressive behaviour among asynchronously hatching siblings in red kites Milvus milvus.}, journal = {Royal Society open science}, volume = {10}, number = {7}, pages = {230328}, pmid = {37476514}, issn = {2054-5703}, abstract = {Aggression represents the backbone of dominance acquisition in several animal societies, where the decision to interact is dictated by its relative cost. Among siblings, such costs are weighted in the light of inclusive fitness, but how this translates to aggression patterns in response to changing external and internal conditions remains unclear. Using a null-model-based approach, we investigate how day-to-day changes in food provisioning affect aggression networks and food allocation in growing red kite (Milvus milvus) nestlings, whose dominance rank is largely dictated by age. We show that older siblings, irrespective of age, change from targeting only close-aged peers (close-competitor pattern) when food provisioning is low, to uniformly attacking all other peers (downward heuristic pattern) as food conditions improve. While food allocation was generally skewed towards the older siblings, the youngest sibling in the nest increased its probability of accessing food as more was provisioned and as downward heuristic patterns became more prominent, suggesting that different aggression patterns allow for catch-up growth after periods of low food. Our results indicate that dynamic aggression patterns within the nest modulate environmental effects on juvenile development by influencing the process of dominance acquisition and potentially impacting the fledging body condition, with far-reaching fitness consequences.}, } @article {pmid37459126, year = {2023}, author = {Prigent, I and Mullon, C}, title = {The molding of intraspecific trait variation by selection under ecological inheritance.}, journal = {Evolution; international journal of organic evolution}, volume = {77}, number = {10}, pages = {2144-2161}, doi = {10.1093/evolut/qpad124}, pmid = {37459126}, issn = {1558-5646}, mesh = {Humans ; *Biological Evolution ; *Polymorphism, Genetic ; Models, Theoretical ; Inheritance Patterns ; Phenotype ; }, abstract = {Organisms continuously modify their environment, often impacting the fitness of future conspecifics due to ecological inheritance. When this inheritance is biased toward kin, selection favors modifications that increase the fitness of downstream individuals. How such selection shapes trait variation within populations remains poorly understood. Using mathematical modelling, we investigate the coevolution of multiple traits in a group-structured population when these traits affect the group environment, which is then bequeathed to future generations. We examine when such coevolution favors polymorphism as well as the resulting associations among traits. We find in particular that two traits become associated when one trait affects the environment while the other influences the likelihood that future kin experience this environment. To illustrate this, we model the coevolution of (a) the attack rate on a local renewable resource, which deteriorates environmental conditions, with (b) dispersal between groups, which reduces the likelihood that kin suffers from such deterioration. We show this often leads to the emergence of two highly differentiated morphs: one that readily disperses and depletes local resources, and another that maintains these resources and tends to remain philopatric. More broadly, we suggest that ecological inheritance can contribute to phenotypic diversity and lead to complex polymorphism.}, } @article {pmid37457894, year = {2023}, author = {Tasaki, E and Mitaka, Y and Takahashi, Y and Waliullah, ASM and Tamannaa, Z and Sakamoto, T and Islam, A and Kamiya, M and Sato, T and Aramaki, S and Kikushima, K and Horikawa, M and Nakamura, K and Kahyo, T and Takata, M and Setou, M and Matsuura, K}, title = {The royal food of termites shows king and queen specificity.}, journal = {PNAS nexus}, volume = {2}, number = {7}, pages = {pgad222}, pmid = {37457894}, issn = {2752-6542}, abstract = {Society in eusocial insects is based on the reproductive division of labor, with a small number of reproductive individuals supported by a large number of nonreproductive individuals. Because inclusive fitness of all colony members depends on the survival and fertility of reproductive members, sterile members provide royals with special treatment. Here, we show that termite kings and queens each receive special food of a different composition from workers. Sequential analysis of feeding processes demonstrated that workers exhibit discriminative trophallaxis, indicating their decision-making capacity in allocating food to the kings and queens. Liquid chromatography tandem-mass spectrometry analyses of the stomodeal food and midgut contents revealed king- and queen-specific compounds, including diacylglycerols and short-chain peptides. Desorption electrospray ionization mass spectrometry imaging analyses of [13]C-labeled termites identified phosphatidylinositol and acetyl-l-carnitine in the royal food. Comparison of the digestive tract structure showed remarkable differences in the volume ratio of the midgut-to-hindgut among castes, indicating that digestive division of labor underlies reproductive division of labor. Our demonstration of king- and queen-specific foods in termites provides insight into the nutritional system that underpins the extraordinary reproduction and longevity of royals in eusocial insects.}, } @article {pmid37454193, year = {2023}, author = {Green, JP and Franco, C and Davidson, AJ and Lee, V and Stockley, P and Beynon, RJ and Hurst, JL}, title = {Cryptic kin discrimination during communal lactation in mice favours cooperation between relatives.}, journal = {Communications biology}, volume = {6}, number = {1}, pages = {734}, pmid = {37454193}, issn = {2399-3642}, mesh = {Female ; Animals ; Mice ; *Lactation ; *Milk ; Mammals ; }, abstract = {Breeding females can cooperate by rearing their offspring communally, sharing synergistic benefits of offspring care but risking exploitation by partners. In lactating mammals, communal rearing occurs mostly among close relatives. Inclusive fitness theory predicts enhanced cooperation between related partners and greater willingness to compensate for any partner under-investment, while females are less likely to bias investment towards own offspring. We use a dual isotopic tracer approach to track individual milk allocation when familiar pairs of sisters or unrelated house mice reared offspring communally. Closely related pairs show lower energy demand and pups experience better access to non-maternal milk. Lactational investment is more skewed between sister partners but females pay greater energetic costs per own offspring reared with an unrelated partner. The choice of close kin as cooperative partners is strongly favoured by these direct as well as indirect benefits, providing a driver to maintain female kin groups for communal breeding.}, } @article {pmid37452552, year = {2023}, author = {Achorn, A and Lindshield, S and Ndiaye, PI and Winking, J and Pruetz, JD}, title = {Reciprocity and beyond: Explaining meat transfers in savanna-dwelling chimpanzees at Fongoli, Senegal.}, journal = {American journal of biological anthropology}, volume = {182}, number = {2}, pages = {224-236}, doi = {10.1002/ajpa.24815}, pmid = {37452552}, issn = {2692-7691}, mesh = {Male ; Animals ; *Pan troglodytes ; *Grassland ; Senegal ; Feeding Behavior ; Meat ; }, abstract = {OBJECTIVES: To understand the function of food sharing among our early hominin ancestors, we can turn to our nonhuman primate relatives for insight. Here, we examined the function of meat sharing by Fongoli chimpanzees, a community of western chimpanzees (Pan troglodytes verus) in southeastern Sénégal.

MATERIALS AND METHODS: We tested three non-mutually exclusive hypotheses that have been used to explain patterns of food sharing: kin selection, generalized reciprocity, and meat-for-mating opportunities. We analyzed meat sharing events (n = 484) resulting from hunts, along with data on copulations, age-sex class, and kinship to determine which variables predict the likelihood of meat sharing during this study period (2006-2019).

RESULTS: We found full or partial support for kin selection, direct reciprocity, and meat-for-mating-opportunities. However, the analyses reveal that reciprocity and a mother/offspring relationship were the strongest predictors of whether or not an individual shared meat.

CONCLUSIONS: The results of this study emphasize the complexity of chimpanzee meat sharing behaviors, especially at a site where social tolerance offers increased opportunities for meat sharing by individuals other than dominant males. These findings can be placed in a referential model to inform hypotheses about the sensitivity of food sharing to environmental pressures, such as resource scarcity in savanna landscapes.}, } @article {pmid37434638, year = {2023}, author = {Bose, APH and Dabernig-Heinz, J and Oberkofler, J and Koch, L and Grimm, J and Sefc, KM and Jordan, A}, title = {Aggression and spatial positioning of kin and non-kin fish in social groups.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {34}, number = {4}, pages = {673-681}, pmid = {37434638}, issn = {1045-2249}, abstract = {Group-living animals are faced with the challenge of sharing space and local resources amongst group members who may be either relatives or non-relatives. Individuals may reduce the inclusive fitness costs they incur from competing with relatives by either reducing their levels of aggression toward kin, or by maintaining physical separation between kin. In this field study, we used the group-living cichlid Neolamprologus multifasciatus to examine whether within-group aggression is reduced among group members that are kin, and whether kin occupy different regions of their group's territory to reduce kin competition over space and local resources. We determined the kinship relationships among cohabiting adults via microsatellite genotyping and then combined these with spatial and behavioral analyses of groups in the wild. We found that aggressive contests between group members declined in frequency with spatial separation between their shelters. Female kin did not engage in aggressive contests with one another, whereas non-kin females did, despite the fact these females lived at similar distances from one another on their groups' territories. Contests within male-male and male-female dyads did not clearly correlate with kinship. Non-kin male-male and male-female dyads lived at more variable distances from one another on their territories than their corresponding kin dyads. Together, our study indicates that contests among group members can be mediated by relatedness in a sex-dependent manner. We also suggest that spatial relationships can play an important role in determining the extent to which group members compete with one another.}, } @article {pmid37339749, year = {2023}, author = {Micheletti, AJC and Ge, E and Zhou, L and Chen, Y and Du, J and Mace, R}, title = {Correction to: 'Religious celibacy brings inclusive fitness benefits' (2022) by Micheletti et al.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2001}, pages = {20231299}, doi = {10.1098/rspb.2023.1299}, pmid = {37339749}, issn = {1471-2954}, } @article {pmid37339747, year = {2023}, author = {Micheletti, AJC and Ge, E and Zhou, L and Chen, Y and Du, J and Mace, R}, title = {Studying human culture with small datasets and evolutionary models.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2001}, pages = {20230753}, pmid = {37339747}, issn = {1471-2954}, mesh = {Humans ; *Biological Evolution ; *Selection, Genetic ; Culture ; }, } @article {pmid37339744, year = {2023}, author = {von Pein, LI and Harper, KT and Zietsch, BP}, title = {No evidence that religious celibacy confers inclusive fitness benefits: a comment on: 'Studying human culture with small datasets and evolutionary models' Micheletti et al. (2022).}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {2001}, pages = {20230176}, pmid = {37339744}, issn = {1471-2954}, mesh = {Humans ; *Sexual Abstinence ; *Selection, Genetic ; Biological Evolution ; Genetic Fitness ; Models, Genetic ; }, } @article {pmid37300791, year = {2023}, author = {Pettay, JE and Danielsbacka, M and Helle, S and Perry, G and Daly, M and Tanskanen, AO}, title = {Parental Investment by Birth Fathers and Stepfathers : Roles of Mating Effort and Childhood Co-residence Duration.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {34}, number = {2}, pages = {276-294}, pmid = {37300791}, issn = {1936-4776}, support = {325857//Academy of Finland/ ; 331400//Academy of Finland/ ; 320162//Academy of Finland/ ; 317808//Academy of Finland/ ; 345183//Strategic Research Council/ ; }, mesh = {Adolescent ; Adult ; Female ; Humans ; Male ; Cross-Sectional Studies ; *Father-Child Relations ; *Fathers/psychology ; Mothers/psychology ; Parenting ; Parents ; Young Adult ; }, abstract = {This study investigates the determinants of paternal investment by birth fathers and stepfathers. Inclusive fitness theory predicts higher parental investment in birth children than stepchildren, and this has consistently been found in previous studies. Here we investigate whether paternal investment varies with childhood co-residence duration and differs between stepfathers and divorced birth fathers by comparing the investment of (1) stepfathers, (2) birth fathers who are separated from the child's mother, and (3) birth fathers who still are in a relationship with her. Path analysis was conducted using cross-sectional data from adolescents and younger adults (aged 17-19, 27-29, and 37-39 years) from the German Family Panel (pairfam), collected in 2010-2011 (n = 8326). As proxies of paternal investment, we used financial and practical help, emotional support, intimacy, and emotional closeness, as reported by the children. We found that birth fathers who were still in a relationship with the mother invested the most, and stepfathers invested the least. Furthermore, the investment of both separated fathers and stepfathers increased with the duration of co-residence with the child. However, in the case of financial help and intimacy, the effect of childhood co-residence duration was stronger in stepfathers than in separated fathers. Our findings support inclusive fitness theory and mating effort theory in explaining social behavior and family dynamics in this population. Furthermore, social environment, such as childhood co-residence was associated with paternal investment.}, } @article {pmid37285032, year = {2023}, author = {Hu, DZ and Gómez Jiménez, FR and VanderLaan, DP}, title = {A Test of the Kin Selection Hypothesis for Female Gynephilia in Thailand.}, journal = {Archives of sexual behavior}, volume = {52}, number = {5}, pages = {2153-2161}, pmid = {37285032}, issn = {1573-2800}, mesh = {Adult ; Child ; Male ; Humans ; Female ; *Homosexuality, Male ; *Gender Identity ; Thailand ; Sexual Behavior ; Reproduction ; Altruism ; }, abstract = {Female gynephilia (i.e., sexual attraction to adult females) is considered an evolutionary paradox because it reduces direct reproduction, yet it is influenced by genetic factors and has persisted over time and across different cultures. The Kin Selection Hypothesis proposes that same-sex attracted individuals offset their lowered direct reproduction by engaging in kin-directed altruism that increases the reproduction of close genetic relatives, thereby enhancing inclusive fitness. Previous research on male same-sex attraction found evidence to support this hypothesis in some cultures. The present study employed a Thai sample to compare altruistic tendencies towards kin and non-kin children in heterosexual women (n = 285), lesbian women (n = 59), toms (i.e., masculine gynephilic females who take on a nonbinary gender identity; n = 181), and dees (i.e., feminine gynephilic females who are attracted to toms; n = 154). The Kin Selection Hypothesis of same-sex attraction predicts that gynephilic groups would show increased kin-directed altruism compared with heterosexual women, but we did not find evidence supporting this prediction. Instead, the tendency to invest more towards kin than non-kin children was more exaggerated in heterosexual women than lesbian women. Also, heterosexual women showed greater dissociation between kin and non-kin altruistic tendencies compared with toms and dees, which may suggest the former's cognition is better attuned for kin-directed altruism. Thus, the present findings were contrary to the Kin Selection Hypothesis for female gynephilia. Alternative explanations regarding the maintenance of genetic factors predisposing individuals to female gynephilia are discussed and require further investigation.}, } @article {pmid37251589, year = {2023}, author = {Choi, J and Lee, S and Kim, H and Park, J}, title = {The role of recognition error in the stability of green-beard genes.}, journal = {Evolution letters}, volume = {7}, number = {3}, pages = {157-167}, pmid = {37251589}, issn = {2056-3744}, abstract = {The empirical examples of the green-beard genes, once a conundrum of evolutionary biology, are accumulating, while theoretical analyses of this topic are occasional compared to those concerning (narrow-sense) kin selection. In particular, the recognition error of the green-beard effect that the cooperator fails to accurately recognize the other cooperators or defectors is readily found in numerous green-beard genes. To our knowledge, however, no model up to date has taken that effect into account. In this article, we investigated the effect of recognition error on the fitness of the green-beard gene. By employing theories of evolutionary games, our mathematical model predicts that the fitness of the green-beard gene is frequency dependent (frequency of the green-beard gene), which was corroborated by experiments performed with yeast FLO1. The experiment also shows that the cells with the green-beard gene (FLO1) are sturdier under severe stress. We conclude that the low recognition error among the cooperators, the higher reward of cooperation, and the higher cost of defection confer an advantage to the green-beard gene under certain conditions, confirmed by numerical simulation as well. Interestingly, we expect that the recognition error to the defectors may promote the cooperator fitness if the cooperator frequency is low and mutual defection is detrimental. Our ternary approach of mathematical analysis, experiments, and simulation lays the groundwork of the standard model for the green-beard gene that can be generalized to other species.}, } @article {pmid37198896, year = {2023}, author = {Antfolk, J and Marklund, E and Nylund, I and Gunst, A}, title = {No Signs of Inclusive Fitness or Reciprocal Altruism in Advantageous Inequity Aversion.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {21}, number = {2}, pages = {14747049231173401}, pmid = {37198896}, issn = {1474-7049}, mesh = {Child ; Humans ; Child, Preschool ; *Altruism ; *Social Behavior ; Affect ; Biological Evolution ; Peer Group ; }, abstract = {Advantageous inequity aversion (i.e., the tendency to respond negatively to unfairness that benefits oneself) usually develops in 6-8-year-olds. However, little is known about the selection pressures that might have shaped this phenomenon. Using data collected from 120 4-8-year-old Finnish children, we tested two evolutionary explanations for the development of advantageous inequity aversion: reciprocal altruism (i.e., benefiting from sharing when the roles are likely reversed in the future) and inclusive fitness (i.e., benefiting from sharing with biological relatives that carry the same alleles). We first successfully replicated a previous experiment, showing that 6-8-year-olds display advantageous inequity aversion by preferring to throw away a resource rather than keep it for themselves. Here, this behavior was also displayed in 5-year-olds. Using a novel experiment, we then asked children to distribute five erasers between themselves, a sibling, a peer, and a stranger. That is, an equal distribution was only possible if throwing away one eraser. We found no support for advantageous inequity aversion being shaped by either inclusive fitness or reciprocal altruism. Future studies could investigate costly signaling and adherence to social norms to avoid negative consequences as ultimate explanations for advantageous inequity aversion.}, } @article {pmid37192926, year = {2023}, author = {Helanterä, H and Ozan, M and Sundström, L}, title = {Relatedness modulates reproductive competition among queens in ant societies with multiple queens.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {34}, number = {3}, pages = {340-345}, pmid = {37192926}, issn = {1045-2249}, abstract = {Reproductive sharing in animal groups with multiple breeders, insects and vertebrates alike, contains elements of both conflict and cooperation, and depends on both relatedness between co-breeders, as well as their internal and external conditions. We studied how queens of the ant Formica fusca adjust their reproductive efforts in response to experimental manipulations of the kin competition regime in their nest. Queens respond to the presence of competitors by increasing their egg laying efforts, but only if the competitors are highly fecund and distantly related. Such a mechanism is likely to decrease harmful competition among close relatives. We demonstrate that queens of Formica fusca fine-tune their cooperative breeding behaviors in response to kinship and fecundity of others in a remarkably precise and flexible manner.}, } @article {pmid37186853, year = {2023}, author = {Riehl, C and LaPergola, JB}, title = {Inclusive fitness explains behavioral diversity in a social bird.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {21}, pages = {e2305610120}, pmid = {37186853}, issn = {1091-6490}, mesh = {Animals ; *Selection, Genetic ; *Genetic Fitness ; Birds ; Biological Evolution ; Models, Genetic ; }, } @article {pmid37161292, year = {2023}, author = {Tanskanen, AO and Helle, S and Danielsbacka, M}, title = {Differential grandparental investment when maternal grandmothers are living versus deceased.}, journal = {Biology letters}, volume = {19}, number = {5}, pages = {20230061}, pmid = {37161292}, issn = {1744-957X}, mesh = {Adolescent ; Humans ; *Grandparents ; Uncertainty ; }, abstract = {Grandparents can increase their inclusive fitness by investing time and resources in their grandchildren. However, not all grandparents make such investments equally, and between-grandparent differences in this regard can be predicted based on paternity uncertainty, lineage and grandparents' sex. Using population-based data for English and Welsh adolescents (n = 1430), we examined whether the death of the most important grandparent (in terms of investment), the maternal grandmother (MGM), changes relative support for existing hypotheses predicting differential grandparental-investment patterns. To contrast the predictions of the grandparental investment hypotheses, we used generalized order-restricted information criterion approximation. We consequently found that, when MGMs are alive, the most-supported hypothesis is 'discriminative grandparental solicitude', which ranks grandparental investment as MGMs > maternal grandfathers (MGFs) > paternal grandmothers (PGMs) > paternal grandfathers (PGFs). However, when MGMs are deceased, the paternity uncertainty hypothesis (MGFs = PGMs > PGFs) receives the most support; this is due to increased investment by PGMs. Thus, when the heaviest investors (i.e. MGMs) are deceased, PGM investments are closer to-but do not exceed-MGF investments.}, } @article {pmid37140644, year = {2023}, author = {Gussone, L and Hüllen, A and Vitt, S and Scherer, U and Thünken, T}, title = {Impact of genetic relatedness on reproductive behavior in Pelvicachromis pulcher, a biparental cichlid fish with mutual mate choice and ornamentation.}, journal = {Die Naturwissenschaften}, volume = {110}, number = {3}, pages = {17}, pmid = {37140644}, issn = {1432-1904}, support = {TH 1615/3-1, TH1615/3-2//Deutsche Forschungsgemeinschaft/ ; SCHU-2927/2-1//Deutsche Forschungsgemeinschaft/ ; }, mesh = {Animals ; Female ; Male ; *Mating Preference, Animal ; *Cichlids/genetics ; Reproduction ; Inbreeding ; Sexual Behavior, Animal ; }, abstract = {Inbreeding can result in inbreeding depression. Therefore, many species seek to avoid inbreeding. However, theory predicts that inbreeding can be beneficial. Accordingly, some species tolerate inbreeding or even prefer mating with close relatives. Evidence for active inbreeding, i.e., kin-mating preference was reported in the biparental African cichlid fish Pelvicachromis taeniatus. Related mating partners revealed better parental cooperation due to kin selection, a potential benefit of inbreeding. In this study, we investigated kin-mating preference in a genetically diverse, outbred F2-lab population of Pelvicachromis pulcher, a closely related species to P. taeniatus. Like P. taeniatus, this species shows mutual ornamentation and mate choice as well as intense biparental brood care. The F1 P. pulcher generation had revealed signs of inbreeding depression but no inbreeding avoidance. We studied mating behavior and aggression in trios consisting of a male P. pulcher, an unfamiliar sister, and an unfamiliar, unrelated female. Because the study focused on kin-mating patterns, female pairs were matched for body size and coloration. The results provide no evidence for inbreeding avoidance but rather suggest inbreeding preference. We also found no significant impact of inbreeding on offspring survival. The results suggest no inbreeding avoidance in P. pulcher; however, the strength of inbreeding preference and inbreeding depression seems to be variable. We discuss possible causes for this variation like context-dependent inbreeding depression. The number of eggs positively correlated with female body size and coloration. Furthermore, the female aggressiveness was positively correlated with female coloration indicating that coloration signal female dominance and quality.}, } @article {pmid37126712, year = {2023}, author = {Koenig, WD and Barve, S and Haydock, J and Dugdale, HL and Oli, MK and Walters, EL}, title = {Lifetime inclusive fitness effects of cooperative polygamy in the acorn woodpecker.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {19}, pages = {e2219345120}, pmid = {37126712}, issn = {1091-6490}, mesh = {Animals ; Female ; Male ; *Marriage ; *Birds ; Social Behavior ; Reproduction ; Altruism ; Cooperative Behavior ; }, abstract = {Although over 50 y have passed since W. D. Hamilton articulated kin selection and inclusive fitness as evolutionary explanations for altruistic behavior, quantifying inclusive fitness continues to be challenging. Here, using 30 y of data and two alternative methods, we outline an approach to measure lifetime inclusive fitness effects of cooperative polygamy (mate-sharing or cobreeding) in the cooperatively breeding acorn woodpecker Melanerpes formicivorus. For both sexes, the number of offspring (observed direct fitness) declined while the number of young parented by related cobreeders (observed indirect fitness effect) increased with cobreeding coalition size. Combining these two factors, the observed inclusive fitness effect of cobreeding was greater than breeding singly for males, while the pattern for females depended on whether fitness was age-weighted, as females breeding singly accrued greater fitness at younger ages than cobreeding females. Accounting for the fitness birds would have obtained by breeding singly, however, lifetime inclusive fitness effects declined with coalition size for males, but were greater for females breeding as duos compared to breeding singly, due largely to indirect fitness effects of kin. Our analyses provide a road map for, and demonstrate the importance of, quantifying indirect fitness as a powerful evolutionary force contributing to the costs and benefits of social behaviors.}, } @article {pmid37094171, year = {2023}, author = {Shah, SS and Rubenstein, DR}, title = {Group augmentation underlies the evolution of complex sociality in the face of environmental instability.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {120}, number = {18}, pages = {e2212211120}, pmid = {37094171}, issn = {1091-6490}, mesh = {Humans ; Male ; Female ; Animals ; *Social Behavior ; *Birds ; Breeding ; Sex ; Reproduction ; Cooperative Behavior ; }, abstract = {Although kin selection is assumed to underlie the evolution of sociality, many vertebrates-including nearly half of all cooperatively breeding birds-form groups that also include unrelated individuals. Theory predicts that despite reducing kin structure, immigration of unrelated individuals into groups can provide direct, group augmentation benefits, particularly when offspring recruitment is insufficient for group persistence. Using population dynamic modeling and analysis of long-term data, we provide clear empirical evidence of group augmentation benefits favoring the evolution and maintenance of complex societies with low kin structure and multiple reproductives. We show that in the superb starling (Lamprotornis superbus)-a plural cooperative breeder that forms large groups with multiple breeding pairs, and related and unrelated nonbreeders of both sexes-offspring recruitment alone cannot prevent group extinction, especially in smaller groups. Further, smaller groups, which stand to benefit more from immigration, exhibit lower reproductive skew for immigrants, suggesting that reproductive opportunities as joining incentives lead to plural breeding. Yet, despite a greater likelihood of becoming a breeder in smaller groups, immigrants are more likely to join larger groups where they experience increased survivorship and greater reproductive success as breeders. Moreover, immigrants form additional breeding pairs, increasing future offspring recruitment into the group and guarding against complete reproductive failure in the face of environmental instability and high nest predation. Thus, plural breeding likely evolves because the benefits of group augmentation by immigrants generate a positive feedback loop that maintains societies with low and mixed kinship, large group sizes, and multiple reproductives.}, } @article {pmid37092004, year = {2023}, author = {Guo, Y and Grueter, CC and Lu, J}, title = {Allomaternal care and 'adoption' in an edge-of-range population of Taihangshan macaques in Northern China.}, journal = {Current zoology}, volume = {69}, number = {2}, pages = {215-218}, pmid = {37092004}, issn = {1674-5507}, } @article {pmid37075326, year = {2023}, author = {van Dokkum, NH and Fagan, LJ and Cullen, M and Loewy, JV}, title = {Assessing HeartSong as a Neonatal Music Therapy Intervention: A Qualitative Study on Personal and Professional Caregivers' Perspectives.}, journal = {Advances in neonatal care : official journal of the National Association of Neonatal Nurses}, volume = {23}, number = {3}, pages = {264-271}, doi = {10.1097/ANC.0000000000001068}, pmid = {37075326}, issn = {1536-0911}, mesh = {Infant ; Infant, Newborn ; Humans ; Intensive Care, Neonatal/methods ; Caregivers ; *Music Therapy/methods ; *Music ; Intensive Care Units, Neonatal ; Parents/psychology ; Infant, Extremely Premature ; }, abstract = {BACKGROUND: The music therapy HeartSong intervention pairs newborn infant heartbeats with parents' Song of Kin. Formal evidence on professional and personal caregiver perspectives of this intervention is lacking.

PURPOSE: This survey study evaluates the HeartSong music therapy intervention from parent and staff perspectives.

METHODS: A qualitative study assessing inclusion of HeartSong for family neonatal intensive care unit (NICU) care surveyed 10 professional caregivers comprising medical and psychosocial NICU teams anonymously reflecting their impressions of the intervention. Digital survey of parents/guardians contacted through semistructured phone interviews relayed impressions of recordings: subsequent setup, Song of Kin selection, and use of HeartSong, including thoughts/feelings about it as an intervention.

RESULTS: Professional and personal caregivers valued the HeartSong intervention for bereavement support, family support, including parental, extended family/infant support, and to enhance bonding. Emergent themes: memory-making, connectedness/closeness, support of parent role, processing mental health needs of stressful NICU days, and subsequent plans for lifelong HeartSong use. Therapeutic experience was named as a crucial intervention aspect and participants recommended the HeartSong as a viable, accessible NICU intervention.

HeartSong's use showed efficacy as a clinical NICU music therapy intervention for families of critically ill and extremely preterm infants, when provided by trained, specialized, board-certified music therapists. Future research focusing on HeartSong in other NICU populations might benefit infants with cardiac disease, parental stress, and anxiety attending to parent-infant bonding. Costs and time benefits related to investment are needed before implementation is considered.}, } @article {pmid37072037, year = {2023}, author = {Fuirst, M and Strickland, D and Freeman, NE and Sutton, AO and Ryan Norris, D}, title = {Early-life sibling conflict in Canada jays has lifetime fitness consequences.}, journal = {Proceedings. Biological sciences}, volume = {290}, number = {1997}, pages = {20221863}, pmid = {37072037}, issn = {1471-2954}, mesh = {Animals ; Humans ; *Siblings ; *Songbirds ; Reproduction ; Ontario ; Birth Order ; Genetic Fitness ; }, abstract = {While delaying natal dispersal can provide short-term benefits for juveniles, lifetime fitness consequences are rarely assessed. Furthermore, competition for limited positions on a natal territory could impose an indirect fitness cost on the winner if the outcome has negative effects on its siblings. We use radio-tracking and 58 years of nesting data in Ontario, Canada to examine the lifetime fitness consequences of sibling expulsion in the Canada jay (Perisoreus canadensis). Six weeks after fledging, intra-brood dominance struggles result in one 'dominant juvenile' (DJ) remaining on the natal territory after expelling its subordinate siblings, the 'ejectees' (EJs). Despite an older age-at-first-reproduction, DJs produced more recruits over their lifetime and had higher first-year survival than EJs, leading to substantially higher direct fitness. Even though DJs incurred an indirect fitness cost by expelling their siblings and there was no evidence that their presence on the natal territory increased their parents' reproductive output the following year, they still had substantially higher inclusive fitness than EJs. Our results demonstrate how early-life sibling conflict can have lifetime consequences and that such fitness differences in Canada jays are driven by the enhanced first-year survival of DJs pursuant to the early-summer expulsion of their sibling competitors.}, } @article {pmid37065817, year = {2023}, author = {Knorr, DA and Fox, M}, title = {An evolutionary perspective on the association between grandmother-mother relationships and maternal mental health among a cohort of pregnant Latina women.}, journal = {Evolution and human behavior : official journal of the Human Behavior and Evolution Society}, volume = {44}, number = {1}, pages = {30-38}, pmid = {37065817}, issn = {1090-5138}, support = {K01 DK105110/DK/NIDDK NIH HHS/United States ; P2C HD041022/HD/NICHD NIH HHS/United States ; R03 DK125524/DK/NIDDK NIH HHS/United States ; }, abstract = {Grandmothers are often critical helpers during a mother's reproductive career. Studies on the developmental origins of health and disease demonstrate how maternal psychological distress can negatively influence fetal development and birth outcomes, highlighting an area in which soon-to-be grandmothers (henceforth "grandmothers") can invest to improve both mother and offspring well-being. Here, we examine if and how a pregnant woman's mental health- specifically, depression, state-anxiety, and pregnancy-related anxiety- is influenced by her relationship with her fetus' maternal and paternal grandmother, controlling for relationship characteristics with her fetus' father. In a cohort of pregnant Latina women in Southern California (N = 216), we assessed social support, geographic proximity, and communication between the fetus' grandmothers and pregnant mother. We assessed maternal mental health with validated questionnaire-based instruments. We find that both social support from and communication with the maternal grandmother were statistically associated with less depression, while no paternal grandmother relationship characteristics were statistically significant in association with any mental health variable. These results align with the idea that maternal grandmothers are more adaptively incentivized to invest in their daughters' well-being during pregnancy than paternal grandmothers are for their daughters-in-law. Results suggest that the positive association of maternal grandmothers with mothers' mental health may not hinge on geographic proximity, but rather, potentially function through emotional support. This work represents a novel perspective describing a psychological and prenatal grandmaternal effect.}, } @article {pmid37046187, year = {2023}, author = {Jones, CT and Meynell, L and Neto, C and Susko, E and Bielawski, JP}, title = {The role of the ecological scaffold in the origin and maintenance of whole-group trait altruism in microbial populations.}, journal = {BMC ecology and evolution}, volume = {23}, number = {1}, pages = {11}, pmid = {37046187}, issn = {2730-7182}, mesh = {*Biological Evolution ; *Altruism ; Models, Theoretical ; Computer Simulation ; Cooperative Behavior ; }, abstract = {BACKGROUND: Kin and multilevel selection provide explanations for the existence of altruism based on traits or processes that enhance the inclusive fitness of an altruist individual. Kin selection is often based on individual-level traits, such as the ability to recognize other altruists, whereas multilevel selection requires a metapopulation structure and dispersal process. These theories are unified by the general principle that altruism can be fixed by positive selection provided the benefit of altruism is preferentially conferred to other altruists. Here we take a different explanatory approach based on the recently proposed concept of an "ecological scaffold". We demonstrate that ecological conditions consisting of a patchy nutrient supply that generates a metapopulation structure, episodic mixing of groups, and severe nutrient limitation, can support or "scaffold" the evolution of altruism in a population of microbes by amplifying drift. This contrasts with recent papers in which the ecological scaffold was shown to support selective processes and demonstrates the power of scaffolding even in the absence of selection.

RESULTS: Using computer simulations motivated by a simple theoretical model, we show that, although an altruistic mutant can be fixed within a single population of non-altruists by drift when nutrients are severely limited, the resulting altruistic population remains vulnerable to non-altruistic mutants. We then show how the imposition of the "ecological scaffold" onto a population of non-altruists alters the balance between selection and drift in a way that supports the fixation and subsequent persistence of altruism despite the possibility of invasion by non-altruists.

CONCLUSIONS: The fixation of an altruistic mutant by drift is possible when supported by ecological conditions that impose a metapopulation structure, episodic mixing of groups, and severe nutrient limitation. This is significant because it offers an alternative explanation for the evolution of altruism based on drift rather than selection. Given the ubiquity of low-nutrient "oligotrophic" environments in which microbes exist (e.g., the open ocean, deep subsurface soils, or under the polar ice caps) our results suggest that altruistic and cooperative behaviors may be highly prevalent among microbial populations.}, } @article {pmid37027070, year = {2023}, author = {Nautiyal, H and Tanaka, H and Huffman, MA}, title = {Anti-predator strategies of adult male Central Himalayan Langurs (Semnopithecus schistaceus) in response to domestic dogs in a human-dominated landscape.}, journal = {Primates; journal of primatology}, volume = {64}, number = {3}, pages = {361-379}, pmid = {37027070}, issn = {1610-7365}, mesh = {Humans ; Animals ; Male ; Dogs ; Female ; *Presbytini ; Reproduction ; Primates ; Predatory Behavior ; India ; }, abstract = {The evolution of predator-prey relationships is an important topic in primatology. Many aspects of primate society have been explained as a response to predation pressure. While predation has been discussed in broad theoretical terms, few systematically collected data exist on the subject. Furthermore, little information exists regarding the inter-male variation in responses to predators. To address this data gap, predatory dog-primate interactions were studied in a 78-member group of habituated, individually recognized Central Himalayan Langurs (CHL) (Semnopithecus schistaceus) living in a high-altitude subsistence agricultural landscape of northern India. We recorded 312 langur-dog interactions over 2 years. These predation events resulted in 15 serious attacks on adult females, infants, juveniles and sub-adults, in eight of which the prey was killed and consumed on the spot. In response to dog predation, adult males performed three types of anti-predator response behaviors: direct fighting with a predator, emitting alarm calls, fleeing and/or freezing. Differences were noted in each male's response to village dogs. The results showed that the likelihood of CHL adult males engaging in more costly counterattacks or attention getting alarm calls were better predicted by the level of investment in the group (genetic relatedness, duration of residency, social relationships), but not rank and mating rate. Long-duration resident adult males performed high and/or intermediate cost behaviors to protect vulnerable members of the group; their potential offspring, maternal siblings or cousins, and adult female social partners. Short-term residents or recent immigrant males exhibited two less energetically costly, more self-preserving behaviors, depending on their rank: (1) high-ranking short-tenure duration males, with high mating frequencies, performed flee and freeze responses; (2) low-ranking, low-mating-frequency males performed more alarm calls. Counterattacks and alarm calls were performed by adult males with relatively more experience with village dogs and were directed towards dogs with predatory histories significantly more often than dogs with non-predatory histories. Natural selection and kin selection have both contributed to the evolution of CHL anti-predator tactics.}, } @article {pmid36974150, year = {2023}, author = {Li, Z and Da, X and Lu, X}, title = {Complementary interactions between indirect and direct fitness in a cooperatively breeding bird.}, journal = {Current zoology}, volume = {69}, number = {1}, pages = {76-81}, pmid = {36974150}, issn = {1674-5507}, abstract = {Altruism is difficult to explain evolutionarily and to understand it, there is a need to quantify the benefits and costs to altruists. Hamilton's theory of kin selection argues that altruism can persist if the costs to altruists are offset by indirect fitness payoffs from helping related recipients. Nevertheless, helping nonkin is also common and in such situations, the costs must be compensated for by direct benefits. While previous researchers tended to evaluate the indirect and direct fitness in isolation, we expect that they have a complementary interaction where altruists are associated with recipients of different relatedness within a population. The prediction is tested with 12 years of data on lifetime reproductive success for a cooperatively breeding bird, Tibetan ground tits Pseudopodoces humilis. Helpers who helped distantly related recipients gained significantly lower indirect benefits than those who helped closely related recipients, but the opposite was true for direct fitness, thereby making these helpers have an equal inclusive fitness. Helping efforts were independent of helpers' relatedness to recipients, but those helping distantly related recipients were more likely to inherit the resident territory, which could be responsible for their high direct reproductive success. Our findings provide an explanatory model for the widespread coexistence of altruists and recipients with varying relatedness within a single population.}, } @article {pmid36972783, year = {2023}, author = {Wild, G and Flear, VJ and Thompson, GJ}, title = {A kin-selection model of fairness in heterogeneous populations.}, journal = {Journal of theoretical biology}, volume = {565}, number = {}, pages = {111469}, doi = {10.1016/j.jtbi.2023.111469}, pmid = {36972783}, issn = {1095-8541}, mesh = {Animals ; Humans ; *Altruism ; *Motivation ; Biological Evolution ; }, abstract = {Humans and other primates exhibit pro-social preferences for fairness. These preferences are thought to be reinforced by strong reciprocity, a policy that rewards fair actors and punishes unfair ones. Theories of fairness based on strong reciprocity have been criticized for overlooking the importance of individual differences in socially heterogeneous populations. Here, we explore the evolution of fairness in a heterogeneous population. We analyse the Ultimatum Game in cases where players' roles in the game are determined by their status. Importantly, our model allows for non-random pairing of players, and so we also explore the role played by kin selection in shaping fairness. Our kin-selection model shows that, when individuals condition their behaviour on their role in the game, fairness can be understood as either altruistic or spiteful. Altruistic fairness directs resources from less valuable members of a genetic lineage to more valuable members of the same lineage, whereas spiteful fairness keeps resources away from the competitors of the actor's high-value relatives. When individuals express fairness unconditionally it can be understood as altruistic or selfish. When it is altruistic, unconditional fairness again serves to direct resources to high-value members of genetic lineages. When it is selfish, unconditional fairness simply improves an individual's own standing. Overall, we expand kin-selection based explanations for fairness to include motivations other than spite. We show, therefore, that one need not invoke strong reciprocity to explain the advantage of fairness in heterogeneous populations.}, } @article {pmid36934761, year = {2023}, author = {Lehtonen, J and Otsuka, J}, title = {Evolutionary game theory of continuous traits from a causal perspective.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {378}, number = {1876}, pages = {20210507}, pmid = {36934761}, issn = {1471-2970}, mesh = {Humans ; *Game Theory ; Biological Evolution ; Models, Theoretical ; *Frailty ; Phenotype ; }, abstract = {Modern evolutionary game theory typically deals with the evolution of continuous, quantitative traits under weak selection, allowing the incorporation of rich biological detail and complicated nonlinear interactions. While these models are commonly used to find candidates for evolutionary endpoints and to approximate evolutionary trajectories, a less appreciated property is their potential to expose and clarify the causal structure of evolutionary processes. The mathematical step of differentiation breaks a nonlinear model into additive components which are more intuitive to interpret, and when combined with a proper causal hypothesis, partial derivatives in such models have a causal meaning. Such an approach has been used in the causal analysis of game-theoretical models in an informal manner. Here we formalize this approach by linking evolutionary game theory to concepts developed in causal modelling over the past century, from path coefficients to the recently proposed causal derivative. There is a direct correspondence between the causal derivative and the derivative used in evolutionary game theory. Some game theoretical models (e.g. kin selection) consist of multiple causal derivatives. Components of these derivatives correspond to components of the causal derivative, to path coefficients, and to edges on a causal graph, formally linking evolutionary game theory to causal modelling. This article is part of the theme issue 'Half a century of evolutionary games: a synthesis of theory, application and future directions'.}, } @article {pmid36934754, year = {2023}, author = {Van Cleve, J}, title = {Evolutionarily stable strategy analysis and its links to demography and genetics through invasion fitness.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {378}, number = {1876}, pages = {20210496}, pmid = {36934754}, issn = {1471-2970}, mesh = {Humans ; *Biological Evolution ; Phenotype ; Uncertainty ; Demography ; *Game Theory ; Models, Genetic ; Selection, Genetic ; }, abstract = {Evolutionarily stable strategy (ESS) analysis pioneered by Maynard Smith and Price took off in part because it often does not require explicit assumptions about the genetics and demography of a population in contrast to population genetic models. Though this simplicity is useful, it obscures the degree to which ESS analysis applies to populations with more realistic genetics and demography: for example, how does ESS analysis handle complexities such as kin selection, group selection and variable environments when phenotypes are affected by multiple genes? In this paper, I review the history of the ESS concept and show how early uncertainty about the method lead to important mathematical theory linking ESS analysis to general population genetic models. I use this theory to emphasize the link between ESS analysis and the concept of invasion fitness. I give examples of how invasion fitness can measure kin selection, group selection and the evolution of linked modifier genes in response to variable environments. The ESSs in these examples depend crucially on demographic and genetic parameters, which highlights how ESS analysis will continue to be an important tool in understanding evolutionary patterns as new models address the increasing abundance of genetic and long-term demographic data in natural populations. This article is part of the theme issue 'Half a century of evolutionary games: a synthesis of theory, application and future directions'.}, } @article {pmid36916702, year = {2023}, author = {Mazal, L and Fajardo, A and Till-Bottraud, I and Corenblit, D and Fumanal, B}, title = {Kin selection, kin recognition and kin discrimination in plants revisited: A claim for considering environmental and genetic variability.}, journal = {Plant, cell & environment}, volume = {46}, number = {7}, pages = {2007-2016}, doi = {10.1111/pce.14584}, pmid = {36916702}, issn = {1365-3040}, mesh = {*Biological Evolution ; Phenotype ; }, } @article {pmid36862026, year = {2023}, author = {Fox, MM and Knorr, DA and Kwon, D and Wiley, KS and Parrish, MH}, title = {How prenatal cortisol levels relate to grandmother-mother relationships among a cohort of Latina women.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {35}, number = {7}, pages = {e23883}, pmid = {36862026}, issn = {1520-6300}, support = {F32 MD015201/MD/NIMHD NIH HHS/United States ; K01 DK105110/DK/NIDDK NIH HHS/United States ; R03 DK125524/DK/NIDDK NIH HHS/United States ; }, mesh = {Female ; Humans ; Pregnancy ; *Mothers/psychology ; *Grandparents ; Hydrocortisone ; Nuclear Family ; Vitamins ; }, abstract = {INTRODUCTION: As part of the human reproductive strategy, mothers receive childcare assistance from others. For kin, allomothers are adaptively incentivized to provide assistance due to inclusive fitness benefits. Previous studies across a broad range of populations identify grandmothers as particularly consistent allomothers. Minimal attention has been paid to the possibility that allomothers may begin investing in offspring quality during the prenatal stage of life. Here, we innovate within the area of grandmother allocare research by examining the prenatal stage of life and biopsychosocial mechanisms by which prenatal grandmother effects may be enacted.

METHODS: Data derive from the Mothers' Cultural Experiences study, a cohort of 107 pregnant Latina women in Southern California. At <16 weeks' gestation, we administered questionnaires, collected morning urine samples, and measured cortisol by enzyme-linked immunosorbent assay, correcting for specific gravity. We measured the soon-to-be maternal and paternal grandmothers' relationship quality, social support, frequency of seeing each other, communicating, and geographic proximity to pregnant mothers, that is, their daughters and daughters-in-law. These measures were self-reported by the pregnant mothers. We assessed how grandmother constructs related to the pregnant women's depression, stress, anxiety, and cortisol levels.

RESULTS: We observed benefits conferred by maternal grandmothers for mothers' prenatal mental health and lower cortisol levels. Paternal grandmothers also conferred mental health benefits to pregnant daughters-in-law, but higher cortisol levels.

CONCLUSION: Our results suggest that grandmothers, especially maternal grandmothers, are able to improve their inclusive fitness by caring for pregnant daughters, and allomother support may positively impact prenatal health. This work extends the traditional cooperative breeding model by identifying a prenatal grandmother effect, and, by examining a maternal biomarker.}, } @article {pmid36802776, year = {2023}, author = {Rodrigues, AMM and Barker, JL and Robinson, EJH}, title = {The evolution of intergroup cooperation.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {378}, number = {1874}, pages = {20220074}, pmid = {36802776}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; *Social Behavior ; Aggression ; Altruism ; Primates ; Cooperative Behavior ; }, abstract = {Sociality is widespread among animals, and involves complex relationships within and between social groups. While intragroup interactions are often cooperative, intergroup interactions typically involve conflict, or at best tolerance. Active cooperation between members of distinct, separate groups occurs very rarely, predominantly in some primate and ant species. Here, we ask why intergroup cooperation is so rare, and what conditions favour its evolution. We present a model incorporating intra- and intergroup relationships and local and long-distance dispersal. We show that dispersal modes play a pivotal role in the evolution of intergroup interactions. Both long-distance and local dispersal processes drive population social structure, and the costs and benefits of intergroup conflict, tolerance and cooperation. Overall, the evolution of multi-group interaction patterns, including both intergroup aggression and intergroup tolerance, or even altruism, is more likely with mostly localized dispersal. However, the evolution of these intergroup relationships may have significant ecological impacts, and this feedback may alter the ecological conditions that favour its own evolution. These results show that the evolution of intergroup cooperation is favoured by a specific set of conditions, and may not be evolutionarily stable. We discuss how our results relate to empirical evidence of intergroup cooperation in ants and primates. This article is part of a discussion meeting issue 'Collective behaviour through time'.}, } @article {pmid36792870, year = {2023}, author = {Santoriello, F and Pukatzki, S}, title = {Type VI Secretion Systems: Environmental and Intra-host Competition of Vibrio cholerae.}, journal = {Advances in experimental medicine and biology}, volume = {1404}, number = {}, pages = {41-63}, pmid = {36792870}, issn = {0065-2598}, mesh = {*Type VI Secretion Systems/genetics/metabolism ; *Vibrio cholerae/genetics/metabolism ; Bacterial Proteins/genetics/metabolism ; Virulence/genetics ; }, abstract = {The Vibrio Type VI Secretion System (T6SS) is a harpoon-like nanomachine that serves as a defense system and is encoded by approximately 25% of all gram-negative bacteria. In this chapter, we describe the structure of the T6SS in different Vibrio species and outline how the use of different T6SS effector and immunity proteins control kin selection. We summarize the genetic loci that encode the structural elements that make up the Vibrio T6SSs and how these gene clusters are regulated. Finally, we provide insights into T6SS-based competitive dynamics, the role of T6SS genetic exchange in those competitive dynamics, and roles for the Vibrio T6SS in virulence.}, } @article {pmid36724459, year = {2023}, author = {Fischer, S and Duffield, C and Davidson, AJ and Bolton, R and Hurst, JL and Stockley, P}, title = {Fitness Costs of Female Competition Linked to Resource Defense and Relatedness of Competitors.}, journal = {The American naturalist}, volume = {201}, number = {2}, pages = {256-268}, doi = {10.1086/722513}, pmid = {36724459}, issn = {1537-5323}, mesh = {Animals ; Mice ; Female ; Humans ; *Social Behavior ; *Cooperative Behavior ; Social Environment ; Siblings ; Reproduction ; }, abstract = {AbstractFemale reproductive success is often limited by access to resources, and this can lead to social competition both within and between kin groups. Theory predicts that both resource availability and relatedness should influence the fitness consequences of social competition. However, testing key predictions requires differentiating the effects of these two factors. Here, we achieve this experimentally by manipulating the social environment of house mice, a facultative communal breeding species with known kin discrimination ability. This allows us to investigate (1) the reproductive costs of defending a limited resource in response to cues of social competition and (2) whether such costs, or their potential mitigation via cooperative behavior, are influenced by the relatedness of competitors. Our results support the hypothesis that resource defense can be costly for females, potentially trading off against maternal investment. When the availability of protected nest sites was limited, subjects (1) were more active, (2) responded more strongly to simulated territory intrusions via competitive signaling, and (3) produced smaller weaned offspring. However, we found no evidence that the propensity for kin to cooperate was influenced by the relatedness of rivals. Communal breeding between sisters occurred independently of the relatedness of competitors and communally breeding sisters weaned fewer offspring when competing with unrelated females, despite our study being designed to prevent infanticide between kin groups. Our findings thus demonstrate that female competition has fitness costs and that associating with kin is beneficial to avoid negative fitness consequences of competing with nonkin, in addition to more widely recognized kin-selected benefits.}, } @article {pmid36717460, year = {2022}, author = {Leake, DW}, title = {Tracing Slow Phenoptosis to the Prenatal Stage in Social Vertebrates.}, journal = {Biochemistry. Biokhimiia}, volume = {87}, number = {12}, pages = {1512-1527}, doi = {10.1134/S0006297922120094}, pmid = {36717460}, issn = {1608-3040}, mesh = {Animals ; Humans ; Aged ; *Aging/genetics ; *Vertebrates ; }, abstract = {Vladimir Skulachev's coining of the term "phenoptosis" 25 years ago (Skulachev, V. P., Biochemistry (Moscow), 62, 1997) highlighted the theoretical possibility that aging is a programmed process to speed the exit of individuals posing some danger to their social group. While rapid "acute phenoptosis" might occur at any age (e.g., to prevent spread of deadly infections), "slow phenoptosis" is generally considered to occur later in life in the form of chronic age-related disorders. However, recent research indicates that risks for such chronic disorders can be greatly raised by early life adversity, especially during the prenatal stage. Much of this research uses indicators of biological aging, the speeding or slowing of natural physiological deterioration in response to environmental inputs, leading to divergence from chronological age. Studies using biological aging indicators commonly find it is accelerated not only in older individuals with chronic disorders, but also in very young individuals with health problems. This review will explain how accelerated biological aging equates to slow phenoptosis. Its occurrence even in the prenatal stage is theoretically supported by W. D. Hamilton's proposal that offsprings detecting they have dangerous mutations should then automatically speed their demise, in order to improve their inclusive fitness by giving their parents the chance to produce other fitter siblings.}, } @article {pmid36717459, year = {2022}, author = {Pandey, T and Ma, DK}, title = {Stress-Induced Phenoptosis: Mechanistic Insights and Evolutionary Implications.}, journal = {Biochemistry. Biokhimiia}, volume = {87}, number = {12}, pages = {1504-1511}, doi = {10.1134/S0006297922120082}, pmid = {36717459}, issn = {1608-3040}, mesh = {Animals ; Humans ; *Caenorhabditis elegans/genetics ; *Apoptosis ; Aging/genetics ; Bacteria ; Signal Transduction ; Biological Evolution ; Mammals ; }, abstract = {Evolution by natural selection results in biological traits that enable organismic adaptation and survival under various stressful environments. External stresses can be sometimes too severe to overcome, leading to organismic death either because of failure in adapting to such stress, or alternatively, through a regulated form of organismic death (phenoptosis). While regulated cell deaths, including apoptosis, have been extensively studied, little is known about the molecular and cellular mechanisms underlying phenoptosis and its evolutionary significance for multicellular organisms. In this article, we review documented phenomena and mechanistic evidence emerging from studies of stress-induced phenoptosis in the multicellular organism C. elegans and stress-induced deaths at cellular levels in organisms ranging from bacteria to mammals, focusing on abiotic and pathogen stresses. Genes and signaling pathways involved in phenoptosis appear to promote organismic death during severe stress and aging, while conferring fitness and immune defense during mild stress and early life, consistent with their antagonistic pleiotropy actions. As cell apoptosis during development can shape tissues and organs, stress-induced phenoptosis may also contribute to possible benefits at the population level, through mechanisms including kin selection, abortive infection, and soma-to-germline resource allocation. Current models can generate experimentally testable predictions and conceptual frameworks with implications for understanding both stress-induced phenoptosis and natural aging.}, } @article {pmid36717438, year = {2022}, author = {Lidsky, PV and Yuan, J and Rulison, JM and Andino-Pavlovsky, R}, title = {Is Aging an Inevitable Characteristic of Organic Life or an Evolutionary Adaptation?.}, journal = {Biochemistry. Biokhimiia}, volume = {87}, number = {12}, pages = {1413-1445}, pmid = {36717438}, issn = {1608-3040}, mesh = {Humans ; Aged ; *Biological Evolution ; *Aging ; Longevity ; Adaptation, Physiological ; }, abstract = {Aging is an evolutionary paradox. Several hypotheses have been proposed to explain it, but none fully explains all the biochemical and ecologic data accumulated over decades of research. We suggest that senescence is a primitive immune strategy which acts to protect an individual's kin from chronic infections. Older organisms are exposed to pathogens for a longer period of time and have a higher likelihood of acquiring infectious diseases. Accordingly, the parasitic load in aged individuals is higher than in younger ones. Given that the probability of pathogen transmission is higher within the kin, the inclusive fitness cost of infection might exceed the benefit of living longer. In this case, programmed lifespan termination might be an evolutionarily stable strategy. Here, we discuss the classical evolutionary hypotheses of aging and compare them with the pathogen control hypothesis, discuss the consistency of these hypotheses with existing empirical data, and present a revised conceptual framework to understand the evolution of aging.}, } @article {pmid36652244, year = {2023}, author = {Wild, G}, title = {Technical comment on "sex ratios when helpers stay at the nest".}, journal = {Evolution; international journal of organic evolution}, volume = {77}, number = {3}, pages = {921-927}, doi = {10.1093/evolut/qpad007}, pmid = {36652244}, issn = {1558-5646}, mesh = {Female ; Male ; *Sex Ratio ; Animals ; }, abstract = {I contributed a paper to volume 60 of the journal. The paper reported on my study of sex-ratio evolution when one sex (females) is helpful but the other sex (males) suffers less from kin competition. I had based my study on a kin-selection model, and so I was dismayed to discover an error in the relatedness calculations therein. Specifically, relatedness coefficients that should have been calculated using a sampling-without-replacement scheme were instead calculated using sampling with replacement. Here, I correct my error and show how it impacts my original findings. I argue that my main conclusions are unchanged. Furthermore, only two new findings contrast with those I presented earlier. First, changing those model details unrelated to the marginal fitness benefits of help does not, in turn, impact substantially the conflict that occurs between mates over the brood sex ratio (I had previously reported some noteworthy impact was possible). Second, help can reduce sex-ratio conflict between mates more effectively when breeders occur in smaller groups (previously, I had said this occurred in larger groups).}, } @article {pmid36621654, year = {2023}, author = {Schradin, C}, title = {Traits don't evolve for the benefit of the species but because they increase individuals' inclusive fitness.}, journal = {Brain, behavior, and immunity}, volume = {109}, number = {}, pages = {89}, doi = {10.1016/j.bbi.2023.01.002}, pmid = {36621654}, issn = {1090-2139}, mesh = {Humans ; *Exercise ; Phenotype ; }, } @article {pmid36617555, year = {2023}, author = {Robinson, SD and Schendel, V and Schroeder, CI and Moen, S and Mueller, A and Walker, AA and McKinnon, N and Neely, GG and Vetter, I and King, GF and Undheim, EAB}, title = {Intra-colony venom diversity contributes to maintaining eusociality in a cooperatively breeding ant.}, journal = {BMC biology}, volume = {21}, number = {1}, pages = {5}, pmid = {36617555}, issn = {1741-7007}, support = {DE160101142//Australian Research Council/ ; DP160104025//Australian Research Council/ ; DP190103787//Australian Research Council/ ; FF160100055//Australian Research Council/ ; APP1136889//Australian National Health & Medical Research Council/ ; 287462//Norges Forskningsråd/ ; /WT_/Wellcome Trust/United Kingdom ; }, mesh = {Animals ; *Ants/genetics ; Venoms ; Australia ; Reproduction ; Social Behavior ; }, abstract = {BACKGROUND: Eusociality is widely considered to evolve through kin selection, where the reproductive success of an individual's close relative is favored at the expense of its own. High genetic relatedness is thus considered a prerequisite for eusociality. While ants are textbook examples of eusocial animals, not all ants form colonies of closely related individuals. One such example is the ectatommine ant Rhytidoponera metallica, which predominantly forms queen-less colonies that have such a low intra-colony relatedness that they have been proposed to represent a transient, unstable form of eusociality. However, R. metallica is among the most abundant and widespread ants on the Australian continent. This apparent contradiction provides an example of how inclusive fitness may not by itself explain the maintenance of eusociality and raises the question of what other selective advantages maintain the eusocial lifestyle of this species.

RESULTS: We provide a comprehensive portrait of the venom of R. metallica and show that the colony-wide venom consists of an exceptionally high diversity of functionally distinct toxins for an ant. These toxins have evolved under strong positive selection, which is normally expected to reduce genetic variance. Yet, R. metallica exhibits remarkable intra-colony variation, with workers sharing only a relatively small proportion of toxins in their venoms. This variation is not due to the presence of chemical castes, but has a genetic foundation that is at least in part explained by toxin allelic diversity.

CONCLUSIONS: Taken together, our results suggest that the toxin diversity contained in R. metallica colonies may be maintained by a form of group selection that selects for colonies that can exploit more resources and defend against a wider range of predators. We propose that increased intra-colony genetic variance resulting from low kinship may itself provide a selective advantage in the form of an expanded pharmacological venom repertoire. These findings provide an example of how group selection on adaptive phenotypes may contribute to maintaining eusociality where a prerequisite for kin selection is diminished.}, } @article {pmid36579168, year = {2022}, author = {Kreider, JJ and Kramer, BH and Komdeur, J and Pen, I}, title = {The evolution of ageing in cooperative breeders.}, journal = {Evolution letters}, volume = {6}, number = {6}, pages = {450-459}, pmid = {36579168}, issn = {2056-3744}, abstract = {Cooperatively breeding animals live longer than their solitary counterparts. This has been suggested for birds, mole rats, and social insects. A common explanation for these long lifespans is that cooperative breeding evolves more readily in long-lived species because lower mortality reduces the rate of territory turnover and thus leads to a limitation of breeding territories. Here, we reverse this argument and show that-rather than being a cause for its evolution-long lifespans are an evolutionary consequence of cooperative breeding. In evolutionary individual-based simulations, we show that natural selection favors a delayed onset of senescence in cooperative breeders, relative to solitary breeders, because cooperative breeders have a delayed age of first reproduction as helpers wait in a reproductive queue to obtain breeder status. Especially long lifespans evolve in cooperative breeders in which queue positions depend on the helpers' age rank among the helpers within the breeding territory. Furthermore, we show that lower genetic relatedness among group members leads to the evolution of longer lifespans. This is because selection against higher mortality is weaker when mortality reduces competition for breeding between relatives. Our results link the evolutionary theory of ageing with kin selection theory, demonstrating that the evolution of ageing in cooperative breeders is driven by the timing of reproduction and kin structure within breeding territories.}, } @article {pmid36521752, year = {2023}, author = {Bruckner, S and Straub, L and Neumann, P and Williams, GR}, title = {Negative but antagonistic effects of neonicotinoid insecticides and ectoparasitic mites Varroa destructor on Apis mellifera honey bee food glands.}, journal = {Chemosphere}, volume = {313}, number = {}, pages = {137535}, doi = {10.1016/j.chemosphere.2022.137535}, pmid = {36521752}, issn = {1879-1298}, mesh = {Bees ; Animals ; *Mites ; *Varroidae ; *Insecticides/toxicity ; *Honey ; Host-Parasite Interactions ; Neonicotinoids/toxicity ; }, abstract = {Collaborative brood care by workers is essential for the functionality of eusocial Apis mellifera honey bee colonies. The hypopharyngeal food glands of workers play a crucial role in this context. Even though there is consensus that ubiquitous ectoparasitic mites Varroa destructor and widespread insecticides, such as neonicotinoids, are major stressors for honey bee health, their impact alone and in combination on the feeding glands of workers is poorly understood. Here, we show that combined exposure to V. destructor and neonicotinoids antagonistically interacted on hypopharyngeal gland size, yet they did not interact on emergence body mass or survival. While the observed effects of the antagonistic interaction were less negative than expected based on the sum of the individual effects, hypopharyngeal gland size was still significantly reduced. Alone, V. destructor parasitism negatively affected emergence body mass, survival, and hypopharyngeal gland size, whereas neonicotinoid exposure reduced hypopharyngeal gland size only. Since size is associated with hypopharyngeal gland functionality, a reduction could result in inadequate brood care. As cooperative brood care is a cornerstone of eusociality, smaller glands could have adverse down-stream effects on inclusive fitness of honey bee colonies. Therefore, our findings highlight the need to further study how ubiquitous stressors like V. destructor and neonicotinoids interact to affect honey bees.}, } @article {pmid36514956, year = {2022}, author = {Davidian, E and Höner, OP}, title = {Kinship and similarity drive coordination of breeding-group choice in male spotted hyenas.}, journal = {Biology letters}, volume = {18}, number = {12}, pages = {20220402}, pmid = {36514956}, issn = {1744-957X}, mesh = {Animals ; Female ; Male ; *Hyaenidae/genetics ; }, abstract = {When and where animals reproduce influences the social, demographic and genetic properties of the groups and populations they live in. We examined the extent to which male spotted hyenas (Crocuta crocuta) coordinate their breeding-group choice. We tested whether their propensity to settle in the same group is shaped by passive processes driven by similarities in their socio-ecological background and genotype or by an adaptive process driven by kin selection. We compared the choices of 148 pairs of same-cohort males that varied in similarity and kinship. We found strong support for both processes. Coordination was highest (70% of pairs) for littermates, who share most cumulative similarity, lower (36%) among peers born in the same group to different mothers, and lowest (7%) among strangers originating from different groups and mothers. Consistent with the kin selection hypothesis, the propensity to choose the same group was density dependent for full siblings and close kin, but not distant kin. Coordination increased as the number of breeding females and male competitors in social groups increased, i.e. when costs of kin competition over mates decreased and benefits of kin cooperation increased. Our results contrast with the traditional view that breeding-group choice and dispersal are predominantly solitary processes.}, } @article {pmid36502806, year = {2023}, author = {Wu, R and Pang, J and Xu, Z and Wu, X and Wang, W and Zheng, Y and Yang, S and Wei, W}, title = {Adolescence Predatory Risk Alters Social Behaviors and Cognitive Ability and Central Oxytocin and Vasopressin Expression in Adult Brandt's Voles.}, journal = {Neuroendocrinology}, volume = {113}, number = {5}, pages = {519-534}, doi = {10.1159/000528608}, pmid = {36502806}, issn = {1423-0194}, mesh = {Male ; Animals ; Female ; *Oxytocin/metabolism ; *Hypothalamo-Hypophyseal System/metabolism ; Pituitary-Adrenal System ; Arvicolinae/metabolism ; Social Behavior ; Arginine Vasopressin/metabolism ; Cognition ; }, abstract = {INTRODUCTION: Stress during adolescence causes long-term behavioral changes in adulthood. We previously found that adolescent exposure to predatory risk augments adolescent social contact and adult parental behavior in Brandt's voles (Lasiopodomys brandtii).

METHODS: Here, we determined whether this experience alters sexual behavior, pair-bond formation, and recognition ability as well as basal HPA axis activity, central oxytocin (OT), and arginine-vasopressin (AVP) expression in adulthood.

RESULTS: In the social interaction test, repeated cat odor (CO) exposure enhanced the frequency of lordosis by female voles toward an unfamiliar opposite-sex conspecific. CO voles preferred to engage with their partners after 48-h cohabitation whereas the control groups did not, which may reflect stable pair bonds in the CO treatment group. Furthermore, adolescent exposure to CO inhibited novel object recognition and place recognition ability, while it influenced social recognition only among adult males. No effect of adolescent CO exposure was observed for basal HPA axis activity, showing a habituation effect. Finally, we found that CO exposure increased OT and decreased AVP expression in the hypothalamus, including the paraventricular nucleus and anterior hypothalamus. The levels of OT in the medial amygdala were lower, and AVP in the lateral septum was higher in CO voles compared with the control.

CONCLUSION: These findings demonstrate that adolescent exposure to predator risk promotes adult reproductive behavior of Brandt's voles. Deficits in recognition ability may necessitate alterations in reproductive strategies to enhance inclusive fitness. OT and AVP systems may play a modulatory role in the alteration of social behaviors elicited by adolescent predatory risk.}, } @article {pmid36483755, year = {2022}, author = {Boon-Falleur, M and Dormont, B and Chevallier, C}, title = {Does higher perceived risk of morbidity and mortality decrease risk-taking?.}, journal = {Royal Society open science}, volume = {9}, number = {12}, pages = {220486}, pmid = {36483755}, issn = {2054-5703}, abstract = {Previous studies have shown that people change their behaviour in response to negative shocks such as economic downturns or natural catastrophes. Indeed, the optimal behaviour in terms of inclusive fitness often varies according to a number of parameters, such as the level of mortality risk in the environment. Beyond unprecedented restrictions in everyday life, the COVID-19 pandemic has profoundly affected people's environment. In this study, we investigated how people form their perception of morbidity and mortality risk associated with COVID-19 and how this perception in turn affects psychological traits, such as risk-taking and patience. We analysed data from a large survey conducted during the first wave in France on 3353 nationally representative people. We found that people use public information on COVID-19 deaths in the area where they live to form their perceived morbidity and mortality risk. Using a structural model approach to lift endogeneity concerns, we found that higher perceived morbidity and mortality risk increases risk aversion. We also found that higher perceived morbidity and mortality risk leads to less patience, although this was only observed for high levels of perceived risk. Our results suggest that people adapt their behaviour to anticipated negative health shocks, namely the risk of becoming sick or dying of COVID-19.}, } @article {pmid36457233, year = {2023}, author = {da Silva, J}, title = {The kin selection theory of genomic imprinting and modes of reproduction in the eusocial Hymenoptera.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {98}, number = {2}, pages = {677-695}, doi = {10.1111/brv.12925}, pmid = {36457233}, issn = {1469-185X}, mesh = {Animals ; Male ; *Genomic Imprinting ; *Ants/genetics ; Parthenogenesis ; Reproduction ; Sex Ratio ; Mammals ; }, abstract = {Genomic imprinting is known from flowering plants and mammals but has not been confirmed for the Hymenoptera even though the eusocial Hymenoptera are prime candidates for this peculiar form of gene expression. Here, the kin selection theory of genomic imprinting is reviewed and applied to the eusocial Hymenoptera. The evidence for imprinting in eusocial Hymenoptera with the typical mode of reproduction, involving the sexual production of diploid female offspring, which develop into workers or gynes, and the arrhenotokous parthenogenesis of haploid males, is also reviewed briefly. However, the focus of this review is how atypical modes of reproduction, involving thelytokous parthenogenesis, hybridisation and androgenesis, may also select for imprinting. In particular, naturally occurring hybridisation in several genera of ants may provide useful tests of the role of kin selection in the evolution of imprinting. Hybridisation is expected to disrupt the coadaptation of antagonistically imprinted loci, and thus affect the phenotypes of hybrids. Some of the limited data available on hybrid worker reproduction and on colony sex ratios support predictions about patterns of imprinting derived from kin selection theory.}, } @article {pmid36425073, year = {2022}, author = {Card, DC and Van Camp, AG and Santonastaso, T and Jensen-Seaman, MI and Anthony, NM and Edwards, SV}, title = {Structure and evolution of the squamate major histocompatibility complex as revealed by two Anolis lizard genomes.}, journal = {Frontiers in genetics}, volume = {13}, number = {}, pages = {979746}, pmid = {36425073}, issn = {1664-8021}, abstract = {The major histocompatibility complex (MHC) is an important genomic region for adaptive immunity and has long been studied in ecological and evolutionary contexts, such as disease resistance and mate and kin selection. The MHC has been investigated extensively in mammals and birds but far less so in squamate reptiles, the third major radiation of amniotes. We localized the core MHC genomic region in two squamate species, the green anole (Anolis carolinensis) and brown anole (A. sagrei), and provide the first detailed characterization of the squamate MHC, including the presence and ordering of known MHC genes in these species and comparative assessments of genomic structure and composition in MHC regions. We find that the Anolis MHC, located on chromosome 2 in both species, contains homologs of many previously-identified mammalian MHC genes in a single core MHC region. The repetitive element composition in anole MHC regions was similar to those observed in mammals but had important distinctions, such as higher proportions of DNA transposons. Moreover, longer introns and intergenic regions result in a much larger squamate MHC region (11.7 Mb and 24.6 Mb in the green and brown anole, respectively). Evolutionary analyses of MHC homologs of anoles and other representative amniotes uncovered generally monophyletic relationships between species-specific homologs and a loss of the peptide-binding domain exon 2 in one of two mhc2β gene homologs of each anole species. Signals of diversifying selection in each anole species was evident across codons of mhc1, many of which appear functionally relevant given known structures of this protein from the green anole, chicken, and human. Altogether, our investigation fills a major gap in understanding of amniote MHC diversity and evolution and provides an important foundation for future squamate-specific or vertebrate-wide investigations of the MHC.}, } @article {pmid36424400, year = {2022}, author = {Kristensen, NP and Ohtsuki, H and Chisholm, RA}, title = {Ancestral social environments plus nonlinear benefits can explain cooperation in human societies.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {20252}, pmid = {36424400}, issn = {2045-2322}, support = {WBS A-0004766-00-00//Ministry of Education - Singapore/ ; JP19H04431//Japan Society for the Promotion of Science/ ; }, mesh = {Humans ; *Game Theory ; *Cooperative Behavior ; Biological Evolution ; Social Environment ; }, abstract = {Human cooperation (paying a cost to benefit others) is puzzling from a Darwinian perspective, particularly in groups with strangers who cannot repay nor are family members. The beneficial effects of cooperation typically increase nonlinearly with the number of cooperators, e.g., increasing returns when cooperation is low and diminishing returns when cooperation is high. Such nonlinearity can allow cooperation between strangers to persist evolutionarily if a large enough proportion of the population are already cooperators. However, if a lone cooperator faces a conflict between the group's and its own interests (a social dilemma), that raises the question of how cooperation arose in the first place. We use a mathematically tractable evolutionary model to formalise a chronological narrative that has previously only been investigated verbally: given that ancient humans interacted mostly with family members (genetic homophily), cooperation evolved first by kin selection, and then persisted in situations with nonlinear benefits as homophily declined or even if interactions with strangers became the norm. The model also predicts the coexistence of cooperators and defectors observed in the human population (polymorphism), and may explain why cooperators in behavioural experiments prefer to condition their contribution on the contributions of others (conditional cooperation in public goods games).}, } @article {pmid36421825, year = {2022}, author = {Kyrgiafini, MA and Giannoulis, T and Moutou, KA and Mamuris, Z}, title = {Investigating the Impact of a Curse: Diseases, Population Isolation, Evolution and the Mother's Curse.}, journal = {Genes}, volume = {13}, number = {11}, pages = {}, pmid = {36421825}, issn = {2073-4425}, mesh = {Male ; Female ; Humans ; *Mothers ; DNA, Mitochondrial/genetics ; Maternal Inheritance/genetics ; *Genome, Mitochondrial/genetics ; Mitochondria/genetics ; }, abstract = {The mitochondrion was characterized for years as the energy factory of the cell, but now its role in many more cellular processes is recognized. The mitochondrion and mitochondrial DNA (mtDNA) also possess a set of distinct properties, including maternal inheritance, that creates the Mother's Curse phenomenon. As mtDNA is inherited from females to all offspring, mutations that are harmful to males tend to accumulate more easily. The Mother's Curse is associated with various diseases, and has a significant effect on males, in many cases even affecting their reproductive ability. Sometimes, it even leads to reproductive isolation, as in crosses between different populations, the mitochondrial genome cannot cooperate effectively with the nuclear one resulting in a mito-nuclear incompatibility and reduce the fitness of the hybrids. This phenomenon is observed both in the laboratory and in natural populations, and have the potential to influence their evolution and speciation. Therefore, it turns out that the study of mitochondria is an exciting field that finds many applications, including pest control, and it can shed light on the molecular mechanism of several diseases, improving successful diagnosis and therapeutics. Finally, mito-nuclear co-adaptation, paternal leakage, and kin selection are some mechanisms that can mitigate the impact of the Mother's Curse.}, } @article {pmid36420711, year = {2022}, author = {Higham, JP}, title = {Kin selection spreads.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {36420711}, issn = {2050-084X}, mesh = {Humans ; Infant ; *Mother-Child Relations ; *Sibling Relations ; Female ; }, abstract = {By spending more time around infants which physically resemble their own, mandrill mothers may increase how frequently their offspring interact with their paternal half siblings.}, } @article {pmid36401071, year = {2023}, author = {Whyte, S and Chan, HF and Ferguson, N and Godwin, M and Hammarberg, K and Torgler, B}, title = {Understanding the Reasons Why Men and Women Do Not Donate Gametes.}, journal = {Reproductive sciences (Thousand Oaks, Calif.)}, volume = {30}, number = {5}, pages = {1651-1659}, pmid = {36401071}, issn = {1933-7205}, mesh = {Male ; Female ; Humans ; *Oocyte Donation ; *Semen ; Tissue Donors ; Spermatozoa ; Oocytes ; Surveys and Questionnaires ; }, abstract = {The global under-supply of sperm and oocyte donors is a serious concern for assisted reproductive medicine. Research has explored self-selected populations of gamete donors and their ex-post rationalisations of why they chose to donate. However, such studies may not provide the necessary insight into why the majority of people do not donate. Utilising the unique open form responses of a large sample (n = 1035) of online survey respondents, we examine the reasons participants cite when asked: "Why haven't you donated your sperm/eggs?." We categorise these responses into four core themes (conditional willingness, barriers, unconsidered, and conscientious objector) and eleven lower-order themes. We find that, on average, women are more conditionally willing (8.2% difference; p = 0.008) to participate in gamete donation than men. We also find that women are more likely than men to justify their non-donation based on their reproductive history (21.3% difference; p = 0.000) or kin selection and inclusive fitness (5.7% difference; p = 0.008). However, compared to women, men are more likely to validate their non-donation based on sociocultural or social norms (6% difference; p = 0.000) or religion (1.7% difference; p = 0.030). That so many of our study participants report in-principal willingness for future participation in gamete donation speaks to the need for increased research on understanding non-donor population preferences, motivations, and behaviours.}, } @article {pmid36377479, year = {2022}, author = {Charpentier, MJE and Poirotte, C and Roura-Torres, B and Amblard-Rambert, P and Willaume, E and Kappeler, PM and Rousset, F and Renoult, JP}, title = {Mandrill mothers associate with infants who look like their own offspring using phenotype matching.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {36377479}, issn = {2050-084X}, mesh = {Humans ; Adult ; Female ; Animals ; *Mandrillus ; Social Behavior ; Phenotype ; Cooperative Behavior ; Maternal Behavior ; }, abstract = {Behavioral discrimination of kin is a key process structuring social relationships in animals. In this study, we provide evidence for discrimination towards non-kin by third-parties through a mechanism of phenotype matching. In mandrills, we recently demonstrated increased facial resemblance among paternally related juvenile and adult females indicating adaptive opportunities for paternal kin recognition. Here, we hypothesize that mandrill mothers use offspring's facial resemblance with other infants to guide offspring's social opportunities towards similar-looking ones. Using deep learning for face recognition in 80 wild mandrill infants, we first show that infants sired by the same father resemble each other the most, independently of their age, sex or maternal origin, extending previous results to the youngest age class. Using long-term behavioral observations on association patterns, and controlling for matrilineal origin, maternal relatedness and infant age and sex, we then show, as predicted, that mothers are spatially closer to infants that resemble their own offspring more, and that this maternal behavior leads to similar-looking infants being spatially associated. We then discuss the different scenarios explaining this result, arguing that an adaptive maternal behavior is a likely explanation. In support of this mechanism and using theoretical modeling, we finally describe a plausible evolutionary process whereby mothers gain fitness benefits by promoting nepotism among paternally related infants. This mechanism, that we call 'second-order kin selection', may extend beyond mother-infant interactions and has the potential to explain cooperative behaviors among non-kin in other social species, including humans.}, } @article {pmid36349451, year = {2023}, author = {Penndorf, J and Ewart, KM and Klump, BC and Martin, JM and Aplin, LM}, title = {Social network analysis reveals context-dependent kin relationships in wild sulphur-crested cockatoos Cacatua galerita.}, journal = {The Journal of animal ecology}, volume = {92}, number = {1}, pages = {171-182}, doi = {10.1111/1365-2656.13839}, pmid = {36349451}, issn = {1365-2656}, mesh = {Female ; Animals ; *Cockatoos ; Social Network Analysis ; *Parrots ; Aggression ; Sulfur ; }, abstract = {A preference to associate with kin facilitates inclusive fitness benefits, and increased tolerance or cooperation between kin may be an added benefit of group living. Many species exhibit preferred associations with kin; however, it is often hard to disentangle active preferences from passive overlap, for example caused by limited dispersal or inheritance of social position. Many parrots exhibit social systems consisting of pair-bonded individuals foraging in variably sized fission-fusion flocks within larger communal roosts of hundreds of individuals. Previous work has shown that, despite these fission-fusion dynamics, individuals can exhibit long-term preferred foraging associations outside their pair bonds. Yet the underlying drivers of these social preferences remain largely unknown. In this study, we use a network approach to examine the influence of kinship on social associations and interactions in wild, communally roosting sulphur-crested cockatoos, Cacatua galerita. We recorded roost co-membership, social associations and interactions in 561 individually marked birds across three neighbouring roosts. We then collected genetic samples from 205 cockatoos, and conducted a relationship analysis to construct a kinship network. Finally, we tested correlations between kinship and four social networks: association, affiliative, low-intensity aggression and high-intensity aggression. Our result showed that while roosting groups were clearly defined, they showed little genetic differentiation or kin structuring. Between roost movement was high, with juveniles, especially females, repeatedly moving between roosts. Both within roosting communities, and when visiting different roosts, individuals preferentially associated with kin. Supporting this, individuals were also more likely to allopreen kin. However, contrary to expectation, individuals preferred to direct aggression towards kin, with this effect only observed when individuals shared roost membership. By measuring social networks within and between large roosting groups, we could remove potential effects of passive spatial overlap on kin structuring. Our study reveals that sulphur-crested cockatoos actively prefer to associate with kin, both within and between roosting groups. By examining this across different interaction types, we further demonstrate that sulphur-crested cockatoos exhibit behavioural and context-dependent interaction rules towards kin. Our results help reveal the drivers of social association in this species, while adding to the evidence for social complexity in parrots.}, } @article {pmid36346221, year = {2022}, author = {Han, B and Wei, Q and Amiri, E and Hu, H and Meng, L and Strand, MK and Tarpy, DR and Xu, S and Li, J and Rueppell, O}, title = {The molecular basis of socially induced egg-size plasticity in honey bees.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {36346221}, issn = {2050-084X}, mesh = {Female ; Bees ; Animals ; *Reproduction ; *Oviposition ; Ovary ; Eggs ; }, abstract = {Reproduction involves the investment of resources into offspring. Although variation in reproductive effort often affects the number of offspring, adjustments of propagule size are also found in numerous species, including the Western honey bee, Apis mellifera. However, the proximate causes of these adjustments are insufficiently understood, especially in oviparous species with complex social organization in which adaptive evolution is shaped by kin selection. Here, we show in a series of experiments that queens predictably and reversibly increase egg size in small colonies and decrease egg size in large colonies, while their ovary size changes in the opposite direction. Additional results suggest that these effects cannot be solely explained by egg-laying rate and are due to the queens' perception of colony size. Egg-size plasticity is associated with quantitative changes of 290 ovarian proteins, most of which relate to energy metabolism, protein transport, and cytoskeleton. Based on functional and network analyses, we further study the small GTPase Rho1 as a candidate regulator of egg size. Spatio-temporal expression analysis via RNAscope and qPCR supports an important role of Rho1 in egg-size determination, and subsequent RNAi-mediated gene knockdown confirmed that Rho1 has a major effect on egg size in honey bees. These results elucidate how the social environment of the honey bee colony may be translated into a specific cellular process to adjust maternal investment into eggs. It remains to be studied how widespread this mechanism is and whether it has consequences for population dynamics and epigenetic influences on offspring phenotype in honey bees and other species.}, } @article {pmid36344830, year = {2023}, author = {Cordoni, G and Comin, M and Collarini, E and Robino, C and Chierto, E and Norscia, I}, title = {Domestic pigs (Sus scrofa) engage in non-random post-conflict affiliation with third parties: cognitive and functional implications.}, journal = {Animal cognition}, volume = {26}, number = {2}, pages = {687-701}, pmid = {36344830}, issn = {1435-9456}, mesh = {Animals ; Swine ; *Social Behavior ; *Behavior, Animal/physiology ; Aggression/psychology ; Sus scrofa ; Cognition ; }, abstract = {In social mammals, conflict resolution involves the reunion of former opponents (aggressor and victim) after an aggressive event (reconciliation) or post-conflict triadic contacts with a third party, started by either opponent (solicited-TSC) or spontaneously offered by the third party (unsolicited-TUC). These post-conflict strategies can serve different functions, including consolation (specifically when TUCs reduce the victim's anxiety). We investigated the possible presence and modulating factors of such strategies on semi-free ranging pigs (Sus scrofa; N = 104), housed at the ethical farm Parva Domus (Cavagnolo, Italy). Kinship was known. Reconciliation was present and mainly occurred between weakly related pigs to possibly improve tolerant cohabitation. Triadic contacts (all present except aggressor TSCs) mostly occurred between close kin. TSCs enacted by victims reduced neither their post-conflict anxiety behaviors nor further attacks by the previous aggressor, possibly because TSCs remained largely unreciprocated. TUCs towards aggressors did not reduce aggressor post-conflict anxiety but limited aggression redirection towards third parties. TUCs towards the victim reduced the victim but not the third-party's anxiety. However, TUCs may also provide inclusive fitness benefits to third parties by benefiting close kin. In sum, pigs engaged in non-random solicited/unsolicited triadic contacts, which suggests that pigs might possess socio-emotional regulation abilities to change their own or others' experience and elements of social appraisal, necessary to detect the emotional arousal of relevant others and (in case of TUCs) take the agency to restore homeostasis.}, } @article {pmid36343483, year = {2022}, author = {Wang, X and Harrison, A}, title = {Non-kin selection enhances complexity in cooperation: A unified quantitative law.}, journal = {Computational biology and chemistry}, volume = {101}, number = {}, pages = {107782}, doi = {10.1016/j.compbiolchem.2022.107782}, pmid = {36343483}, issn = {1476-928X}, support = {BB/E001742/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Humans ; *Biological Evolution ; Genotype ; }, abstract = {How cooperation evolves in the presence of selfishness is a core problem in evolutionary biology. Selfish individuals tend to benefit themselves, which makes it harder to maintain cooperation between unrelated individuals and for living systems to evolve towards complex organizations. The general evolutionary model presented here identifies that non-kin selection is the root cause for cooperation between unrelated individuals and can enable and maintain higher complexity of biological organizations (the coexistence of more individuals of different types). The maintained number of genotypes within a cooperation organization is shown to follow a universal exponential law as a quantitative function of the population size and non-kin selection strength, showing a gene-pool-size invariance. Our results highlight that non-kin selection may be a hallmark of biological evolution, and play an important role in shaping life's potentials.}, } @article {pmid36333950, year = {2023}, author = {Hammer, TJ and Easton-Calabria, A and Moran, NA}, title = {Microbiome assembly and maintenance across the lifespan of bumble bee workers.}, journal = {Molecular ecology}, volume = {32}, number = {3}, pages = {724-740}, pmid = {36333950}, issn = {1365-294X}, support = {R35 GM131738/GM/NIGMS NIH HHS/United States ; R35GM131738/NH/NIH HHS/United States ; 2018-08156//National Institute of Food and Agriculture/ ; }, mesh = {Humans ; Bees/genetics ; Animals ; Longevity/genetics ; RNA, Ribosomal, 16S/genetics ; *Microbiota/genetics ; *Gastrointestinal Microbiome/genetics ; Bacteria/genetics ; }, abstract = {How a host's microbiome changes over its lifespan can influence development and ageing. As these temporal patterns have only been described in detail for a handful of hosts, an important next step is to compare microbiome succession more broadly and investigate why it varies. Here we characterize the temporal dynamics and stability of the bumble bee worker gut microbiome. Bumble bees have simple and host-specific gut microbiomes, and their microbial dynamics may influence health and pollination services. We used 16S rRNA gene sequencing, quantitative PCR and metagenomics to characterize gut microbiomes over the lifespan of Bombus impatiens workers. We also sequenced gut transcriptomes to examine host factors that may control the microbiome. At the community level, microbiome assembly is highly predictable and similar to patterns of primary succession observed in the human gut. However, at the strain level, partitioning of bacterial variants among colonies suggests stochastic colonization events similar to those observed in flies and nematodes. We also find strong differences in temporal dynamics among symbiont species, suggesting ecological differences among microbiome members in colonization and persistence. Finally, we show that both the gut microbiome and host transcriptome-including expression of key immunity genes-stabilize, as opposed to senesce, with age. We suggest that in highly social groups such as bumble bees, maintenance of both microbiomes and immunity contribute to inclusive fitness, and thus remain under selection even in old age. Our findings provide a foundation for exploring the mechanisms and functional outcomes of bee microbiome succession.}, } @article {pmid36330299, year = {2022}, author = {Biernaskie, JM}, title = {Kin selection theory and the design of cooperative crops.}, journal = {Evolutionary applications}, volume = {15}, number = {10}, pages = {1555-1564}, pmid = {36330299}, issn = {1752-4571}, abstract = {In agriculture and plant breeding, plant traits may be favoured because they benefit neighbouring plants and ultimately increase total crop yield. This idea of promoting cooperation among crop plants has existed almost as long as W.D. Hamilton's inclusive fitness (kin selection) theory, the leading framework for explaining cooperation in biology. However, kin selection thinking has not been adequately applied to the idea of cooperative crops. Here, I give an overview of modern kin selection theory and consider how it explains three key strategies for designing cooperative crops: (1) selection for a less-competitive plant type (a 'communal ideotype'); (2) group-level selection for yield; and (3) exploiting naturally selected cooperation. The first two strategies, using artificial selection, have been successful in the past but suffer from limitations that could hinder future progress. Instead, I propose an alternative strategy and a new 'colonial ideotype' that exploits past natural selection for cooperation among the modules (e.g., branches or stems) of individual plants. More generally, I suggest that Hamiltonian agriculture-a kin selection view of agriculture and plant breeding-transforms our understanding of how to improve crops of the future.}, } @article {pmid36259168, year = {2022}, author = {Barreto Filho, MM and Vieira, HH and Morris, JJ and Bagatini, IL}, title = {Species-specific effects and the ecological role of programmed cell death in the microalgae Ankistrodesmus (Sphaeropleales, Selenastraceae).}, journal = {Biology letters}, volume = {18}, number = {10}, pages = {20220259}, pmid = {36259168}, issn = {1744-957X}, mesh = {*Microalgae ; Phytoplankton ; Apoptosis/physiology ; Species Specificity ; Nitrogen ; }, abstract = {Reports of programmed cell death (PCD) in phytoplankton raise questions about the ecological evolutionary role of cell death in these organisms. We induced PCD by nitrogen deprivation and unregulated cell death (non-PCD) in one strain of the green microalga Ankistrodesmus densus and investigated the effects of the cell death supernatants on phylogenetically related co-occurring organisms using growth rates and maximum biomass as proxies of fitness. PCD-released materials from A. densus CCMA-UFSCar-3 significantly increased growth rates of two conspecific strains compared to healthy culture (HC) supernatants and improved the maximum biomass of all A. densus strains compared to related species. Although growth rates of non-A. densus with PCD supernatants were not statistically different from HC treatment, biomass gain was significantly reduced. Thus, the organic substances released by PCD, possibly nitrogenous compounds, could promote conspecific growth. These results support the argument that PCD may differentiate species or subtypes and increases inclusive fitness in this model unicellular chlorophyte. Further research, however, is needed to identify the responsible molecules and how they interact with cells to provide the PCD benefits.}, } @article {pmid36251655, year = {2022}, author = {Khadraoui, M and Merritt, JR and Hoekstra, HE and Bendesky, A}, title = {Post-mating parental behavior trajectories differ across four species of deer mice.}, journal = {PloS one}, volume = {17}, number = {10}, pages = {e0276052}, pmid = {36251655}, issn = {1932-6203}, support = {/HHMI/Howard Hughes Medical Institute/United States ; }, mesh = {Animals ; Female ; Male ; Paternal Behavior ; *Peromyscus ; Pregnancy ; *Reproduction ; }, abstract = {Among species, parental behaviors vary in their magnitude, onset relative to reproduction, and sexual dimorphism. In deer mice (genus Peromyscus), while most species are promiscuous with low paternal care, monogamy and biparental care have evolved at least twice under different ecological conditions. Here, in a common laboratory setting, we monitored parental behaviors of males and females of two promiscuous (eastern deer mouse P. maniculatus and white-footed mouse P. leucopus) and two monogamous (oldfield mouse P. polionotus and California mouse P. californicus) species from before mating to after giving birth. In the promiscuous species, females showed parental behaviors largely after parturition, while males showed little parental care. In contrast, both sexes of monogamous species performed parental behaviors. However, while oldfield mice began to display parental behaviors before mating, California mice showed robust parental care behaviors only postpartum. These different parental-care trajectories in the two monogamous species align with their socioecology. Oldfield mice have overlapping home ranges with relatives, so infants they encounter, even if not their own, are likely to be closely related. By contrast, California mice disperse longer distances into exclusive territories with possibly unrelated neighbors, decreasing the inclusive fitness benefits of caring for unfamiliar pups before parenthood. Together, we find that patterns of parental behaviors in Peromyscus are consistent with predictions from inclusive fitness theory.}, } @article {pmid36218362, year = {2022}, author = {Liu, Y and Huang, R and Chen, Y and Miao, Y and Štefanič, P and Mandic-Mulec, I and Zhang, R and Shen, Q and Xu, Z}, title = {Involvement of Flagellin in Kin Recognition between Bacillus velezensis Strains.}, journal = {mSystems}, volume = {7}, number = {6}, pages = {e0077822}, pmid = {36218362}, issn = {2379-5077}, mesh = {*Flagellin/genetics ; *Bacillus/genetics ; Polymorphism, Genetic ; Amino Acid Sequence ; }, abstract = {Kin discrimination in nature is an effective way for bacteria to stabilize population cooperation and maintain progeny benefits. However, so far, the research on kin discrimination for Bacillus still has concentrated on "attack and defense" between cells and diffusion-dependent molecular signals of quorum sensing, kin recognition in Bacillus, however, has not been reported. To determine whether flagellar is involve in the kin recognition of Bacillus, we constructed Bacillus velezensis SQR9 assembled with flagellin of its kin and non-kin strains, and performed a swarm boundary assay with SQR9, then analyzed sequence variation of flagellin and other flagellar structural proteins in B. velezensis genus. Our results showed that SQR9 assembled with flagellin of non-kin strains was more likely to form a border phenotype with wild-type strain SQR9 in swarm assay than that of kin strains, and that non-kin strains had greater variation in flagellin than kin strains. In B. velezensis, these variations in flagellin were prevalent and had evolved significantly faster than other flagellar structural proteins. Therefore, we proposed that flagellin is an effective tool partly involved in the kin recognition of B. velezensis strains. IMPORTANCE Kin selection plays an important role in stabilizing population cooperation and maintaining the progeny benefits for bacteria in nature. However, to date, the role of flagellin in kin recognition in Bacillus has not been reported. By using rhizospheric Bacillus velezensis SQR9, we accomplished flagellin region interchange among its related strains, and show that flagellin acts as a mediator to distinguish kin from non-kin in B. velezensis. We demonstrated the polymorphism of flagellin in B. velezensis through alignment analysis of flagellin protein sequences. Therefore, it was proposed that flagellin was likely to be an effective tool for mediating kin recognition in B. velezensis.}, } @article {pmid36196551, year = {2022}, author = {García-Ruiz, I and Taborsky, M}, title = {Group augmentation on trial: helpers in small groups enhance antipredator defence of eggs.}, journal = {Biology letters}, volume = {18}, number = {10}, pages = {20220170}, pmid = {36196551}, issn = {1744-957X}, mesh = {Altruism ; Animals ; *Cichlids ; Cooperative Behavior ; *Helping Behavior ; Reproduction ; Sand ; }, abstract = {Mechanisms selecting for the evolution of cooperative breeding are hotly debated. While kin selection theory has been the central paradigm to explain the seemingly altruistic behaviour of non-reproducing helpers, it is increasingly recognized that direct fitness benefits may be highly relevant. The group augmentation hypothesis proposes that alloparental care may evolve to enhance group size when larger groups yield increased survival and/or reproductive success. However, there is a lack of empirical tests. Here we use the cooperatively breeding cichlid fish Neolamprologus pulcher, in which group size predicts survival and group stability, to test this hypothesis experimentally by prompting two cooperative tasks: defence against an egg predator and digging out sand from the breeding shelter. We controlled for alternative mechanisms such as kin selection, load lightening and coercion. As predicted by the group augmentation hypothesis, helpers increased defence against an egg predator in small compared with large groups. This difference was only evident in large helpers owing to size-specific task specialization. Furthermore, helpers showed more digging effort in the breeding chamber compared with alternative personal shelters, indicating that digging is an altruistic service to the dominant breeders.}, } @article {pmid36191234, year = {2022}, author = {Scott, TJ}, title = {Cooperation loci are more pleiotropic than private loci in the bacterium Pseudomonas aeruginosa.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {41}, pages = {e2214827119}, pmid = {36191234}, issn = {1091-6490}, mesh = {*Genetic Pleiotropy ; Mutation ; *Pseudomonas aeruginosa/genetics/metabolism ; }, abstract = {Pleiotropy may affect the maintenance of cooperation by limiting cheater mutants if such mutants lose other important traits. If pleiotropy limits cheaters, selection may favor cooperation loci that are more pleiotropic. However, the same should not be true for private loci with functions unrelated to cooperation. Pleiotropy in cooperative loci has mostly been studied with single loci and has not been measured on a wide scale or compared to a suitable set of control loci with private functions. I remedy this gap by comparing genomic measures of pleiotropy in previously identified cooperative and private loci in Pseudomonas aeruginosa. I found that cooperative loci in P. aeruginosa tended to be more pleiotropic than private loci according to the number of protein-protein interactions, the number of gene ontology terms, and gene expression specificity. These results show that pleiotropy may be a general way to limit cheating and that cooperation may shape pleiotropy in the genome.}, } @article {pmid36134889, year = {2022}, author = {Grebe, NM and Hirwa, JP and Stoinski, TS and Vigilant, L and Rosenbaum, S}, title = {Mountain gorillas maintain strong affiliative biases for maternal siblings despite high male reproductive skew and extensive exposure to paternal kin.}, journal = {eLife}, volume = {11}, number = {}, pages = {}, pmid = {36134889}, issn = {2050-084X}, mesh = {Animals ; Bias ; Family ; *Gorilla gorilla ; Humans ; Male ; Mammals ; Primates ; *Reproduction ; Siblings ; }, abstract = {Evolutionary theories predict that sibling relationships will reflect a complex balance of cooperative and competitive dynamics. In most mammals, dispersal and death patterns mean that sibling relationships occur in a relatively narrow window during development and/or only with same-sex individuals. Besides humans, one notable exception is mountain gorillas, in which non-sex-biased dispersal, relatively stable group composition, and the long reproductive tenures of alpha males mean that animals routinely reside with both maternally and paternally related siblings, of the same and opposite sex, throughout their lives. Using nearly 40,000 hr of behavioral data collected over 14 years on 699 sibling and 1235 non-sibling pairs of wild mountain gorillas, we demonstrate that individuals have strong affiliative preferences for full and maternal siblings over paternal siblings or unrelated animals, consistent with an inability to discriminate paternal kin. Intriguingly, however, aggression data imply the opposite. Aggression rates were statistically indistinguishable among all types of dyads except one: in mixed-sex dyads, non-siblings engaged in substantially more aggression than siblings of any type. This pattern suggests mountain gorillas may be capable of distinguishing paternal kin but nonetheless choose not to affiliate with them over non-kin. We observe a preference for maternal kin in a species with a high reproductive skew (i.e. high relatedness certainty), even though low reproductive skew (i.e. low relatedness certainty) is believed to underlie such biases in other non-human primates. Our results call into question reasons for strong maternal kin biases when paternal kin are identifiable, familiar, and similarly likely to be long-term groupmates, and they may also suggest behavioral mismatches at play during a transitional period in mountain gorilla society.}, } @article {pmid36129331, year = {2022}, author = {Kulich, HR and Bass, SR and Piva, SR and Nindl, B and Koontz, AM}, title = {Preliminary feasibility and acute physiological effects of a single session of upper limb vibration training for persons with spinal cord injury.}, journal = {The journal of spinal cord medicine}, volume = {}, number = {}, pages = {1-11}, doi = {10.1080/10790268.2022.2122332}, pmid = {36129331}, issn = {2045-7723}, abstract = {CONTEXT: Strong upper limb musculature is essential for persons with spinal cord injury (SCI) to operate a manual wheelchair and live independently. Targeted upper limb vibration may be a viable exercise modality to build muscle efficiently while eliminating some of the barriers associated with exercise for persons with SCI.

OBJECTIVE: The purpose of this study was to assess preliminary feasibility of completing a single exercise session of upper limb vibration and compare the acute physiological effects to a single session of standard dumbbell resistance exercise.

METHODS: Individuals with SCI performed seven upper limb exercises (1) isometrically using a vibrating dumbbell at 30 Hz for 60 s (n = 22) and (2) using a standard isotonic resistance protocol (n = 15).

RESULTS: Nineteen (86.4%) of 22 participants were able to perform all vibration exercises at 30 Hz but hold time success rates varied from 33% (side flies and front raises) to 95% (internal rotation). No significant differences were found between vibration exercise and standard resistance protocol for blood lactate, power output, and heart rate (P > 0.05). Perceptions of the training were positive, with most participants (>70%) expressing interest to train with vibration in the future.

CONCLUSIONS: Vibration training was not feasible for all participants, suggesting an individualized approach to starting weight and progression may be necessary. Similar acute physiological changes were seen between vibration exercise and standard resistance protocol, suggesting they could have similar benefits. Additional research is needed to determine if vibration exercise is feasible and beneficial to incorporate into a long-term training program.}, } @article {pmid36109560, year = {2022}, author = {Simpson, CR}, title = {Social Support and Network Formation in a Small-Scale Horticulturalist Population.}, journal = {Scientific data}, volume = {9}, number = {1}, pages = {570}, pmid = {36109560}, issn = {2052-4463}, support = {pf170158//British Academy/ ; }, mesh = {Adult ; Altruism ; Biological Evolution ; Humans ; *Social Networking ; *Social Support ; }, abstract = {Evolutionary studies of cooperation in traditional human societies suggest that helping family and responding in kind when helped are the primary mechanisms for informally distributing resources vital to day-to-day survival (e.g., food, knowledge, money, childcare). However, these studies generally rely on forms of regression analysis that disregard complex interdependences between aid, resulting in the implicit assumption that kinship and reciprocity drive the emergence of entire networks of supportive social bonds. Here I evaluate this assumption using individual-oriented simulations of network formation (i.e., Stochastic Actor-Oriented Models). Specifically, I test standard predictions of cooperation derived from the evolutionary theories of kin selection and reciprocal altruism alongside well-established sociological predictions around the self-organisation of asymmetric relationships. Simulations are calibrated to exceptional public data on genetic relatedness and the provision of tangible aid amongst all 108 adult residents of a village of indigenous horticulturalists in Nicaragua (11,556 ordered dyads). Results indicate that relatedness and reciprocity are markedly less important to whom one helps compared to the supra-dyadic arrangement of the tangible aid network itself.}, } @article {pmid36097350, year = {2022}, author = {Cenzer, M and M'Gonigle, LK}, title = {Co-evolution of dormancy and dispersal in spatially autocorrelated landscapes.}, journal = {Evolution; international journal of organic evolution}, volume = {76}, number = {11}, pages = {2769-2777}, pmid = {36097350}, issn = {1558-5646}, mesh = {*Biological Evolution ; Spatial Analysis ; }, abstract = {The evolution of dispersal can be driven by spatial processes, such as landscape structure, and temporal processes, such as disturbance. Dormancy, or dispersal in time, is generally thought to evolve in response to temporal processes. In spite of broad empirical and theoretical evidence of trade-offs between dispersal and dormancy, we lack evidence that spatial structure can drive the evolution of dormancy. Here, we develop a simulation-based model of the joint evolution of dispersal and dormancy in spatially heterogeneous landscapes. We show that dormancy and dispersal are each favored under different landscape conditions, but not simultaneously under any of the conditions we tested. We further show that, when dispersal distances are short, dormancy can evolve directly in response to landscape structure. In this case, selection is primarily driven by benefits associated with avoiding kin competition. Our results are similar in both highly simplified and realistically complex landscapes.}, } @article {pmid36071078, year = {2022}, author = {Ibrahim, AM}, title = {The conditional defector strategies can violate the most crucial supporting mechanisms of cooperation.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {15157}, pmid = {36071078}, issn = {2045-2322}, abstract = {Cooperation is essential for all domains of life. Yet, ironically, it is intrinsically vulnerable to exploitation by cheats. Hence, an explanatory necessity spurs many evolutionary biologists to search for mechanisms that could support cooperation. In general, cooperation can emerge and be maintained when cooperators are sufficiently interacting with themselves. This communication provides a kind of assortment and reciprocity. The most crucial and common mechanisms to achieve that task are kin selection, spatial structure, and enforcement (punishment). Here, we used agent-based simulation models to investigate these pivotal mechanisms against conditional defector strategies. We concluded that the latter could easily violate the former and take over the population. This surprising outcome may urge us to rethink the evolution of cooperation, as it illustrates that maintaining cooperation may be more difficult than previously thought. Moreover, empirical applications may support these theoretical findings, such as invading the cooperator population of pathogens by genetically engineered conditional defectors, which could be a potential therapy for many incurable diseases.}, } @article {pmid36061780, year = {2022}, author = {Fan, Y and Zhang, R and Zhang, Y and Yue, M}, title = {The effects of genetic distance, nutrient conditions, and recognition ways on outcomes of kin recognition in Glechoma longituba.}, journal = {Frontiers in plant science}, volume = {13}, number = {}, pages = {950758}, pmid = {36061780}, issn = {1664-462X}, abstract = {Kin recognition might help plants decrease competitive cost and improve inclusive fitness with close genes; thus it might interact with environmental factors to affect communities. Whether and how various factors, such as the genetic distance of neighbors, environmental stressors, or the way a plant recognizes its neighbors, might modify plant growth strategies remains unclear. To answer these questions, we conducted experiments in which ramets of a clonal plant, Glechoma longituba, were grown adjacent to different genetically related neighbors (clone kin / close kin / distant kin) in different nutrient conditions (high / medium / low), or with only root exudates from pre-treatment in culture solution. By comparing competitive traits, we found that: (1) kin recognition in G. longituba was enhanced with closer genetic distance; (2) the outcomes of kin recognition were influenced by the extent of nutrient shortage; (3) kin recognition helped to alleviate the nutrient shortage effect; (4) kin recognition via root exudates affected only below-ground growth. Our results provide new insights on the potential for manipulating the outcome of kin recognition by altering neighbor genetic distance, nutrient conditions and recognition ways. Moreover, kin recognition can help plants mitigate the effects of nutrient shortage, with potential implications in agricultural research.}, } @article {pmid36051883, year = {2022}, author = {Li, H and Tan, Y and Zhang, D}, title = {Genomic discovery and structural dissection of a novel type of polymorphic toxin system in gram-positive bacteria.}, journal = {Computational and structural biotechnology journal}, volume = {20}, number = {}, pages = {4517-4531}, pmid = {36051883}, issn = {2001-0370}, abstract = {Bacteria have developed several molecular conflict systems to facilitate kin recognition and non-kin competition to gain advantages in the acquisition of growth niches and of limited resources. One such example is a large class of so-called polymorphic toxin systems (PTSs), which comprise a variety of the toxin proteins secreted via T2SS, T5SS, T6SS, T7SS and many others. These systems are highly divergent in terms of sequence/structure, domain architecture, toxin-immunity association, and organization of the toxin loci, which makes it difficult to identify and characterize novel systems using traditional experimental and bioinformatic strategies. In recent years, we have been developing and utilizing unique genome-mining strategies and pipelines, based on the organizational principles of both domain architectures and genomic loci of PTSs, for an effective and comprehensive discovery of novel PTSs, dissection of their components, and prediction of their structures and functions. In this study, we present our systematic discovery of a new type of PTS (S8-PTS) in several gram-positive bacteria. We show that the S8-PTS contains three components: a peptidase of the S8 family (subtilases), a polymorphic toxin, and an immunity protein. We delineated the typical organization of these polymorphic toxins, in which a N-terminal signal peptide is followed by a potential receptor binding domain, BetaH, and one of 16 toxin domains. We classified each toxin domain by the distinct superfamily to which it belongs, identifying nine BECR ribonucleases, one Restriction Endonuclease, one HNH nuclease, two novel toxin domains homologous to the VOC enzymes, one toxin domain with the Frataxin-like fold, and several other unique toxin families such as Ntox33 and HicA. Accordingly, we identified 20 immunity families and classified them into different classes of folds. Further, we show that the S8-PTS-associated peptidases are analogous to many other processing peptidases found in T5SS, T7SS, T9SS, and many proprotein-processing peptidases, indicating that they function to release the toxin domains during secretion. The S8-PTSs are mostly found in animal and plant-associated bacteria, including many pathogens. We propose S8-PTSs will facilitate the competition of these bacteria with other microbes or contribute to the pathogen-host interactions.}, } @article {pmid36033028, year = {2022}, author = {Salem, AAMS and Abdelsattar, M and Abu Al-Diyar, M and Al-Hwailah, AH and Derar, E and Al-Hamdan, NAH and Tilwani, SA}, title = {Altruistic behaviors and cooperation among gifted adolescents.}, journal = {Frontiers in psychology}, volume = {13}, number = {}, pages = {945766}, pmid = {36033028}, issn = {1664-1078}, abstract = {The present study is a differential study that describes the nature of the relationship between cooperation and altruistic behavior in a sample of gifted adolescents in three universities in Egypt and Kuwait University. It also identified the differences between males/females, and senior students/junior students in both cooperation and altruism. A total of 237 gifted adolescents-with average age 21.3 ± SD 2.6 years-from three Egyptian universities: Alexandria University, Sadat Academy for Management Sciences, and Suez University (in Egypt), and Kuwait University, were involved in this study. Measures used in the study include the Scales for Rating the Behavioral Characteristics of Superior Students (SRBCSS), Generative Altruism Scale (GAlS), and The Cooperative/Competitive Strategy Scale (CCSS). Results revealed that there is a significant positive relationship between altruism and cooperation among gifted adolescents. Also, findings show that there are statistically significant differences between males and females in both altruism and cooperation. In addition, there are differences statistically significant between senior students and junior students in both altruism and cooperation in favor of senior students. It is recommended that altruism and cooperation intervention-based programs should be designed to increase the adaptive behaviors of adolescents.}, } @article {pmid35999250, year = {2022}, author = {Helle, S and Tanskanen, AO and Pettay, JE and Danielsbacka, M}, title = {The interplay of grandparental investment according to the survival status of other grandparent types.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {14390}, pmid = {35999250}, issn = {2045-2322}, mesh = {Adolescent ; Bayes Theorem ; Child ; Child Health ; *Grandparents ; Humans ; Intergenerational Relations ; Surveys and Questionnaires ; }, abstract = {Inclusive fitness theory predicts that grandparental investment in grandchildren aims to maximise their inclusive fitness. Owing to an increasing overlap between successive generations in modern affluent populations, the importance of grandparental investment remains high. Despite the growing literature, there is limited knowledge regarding how the survival status of different grandparent types influences each other's investment in grandchildren. This question was studied by using the Involved Grandparenting and Child Well-Being Survey, which provided nationally representative data of English and Welsh adolescents aged 11-16-years. We applied Bayesian structural equation modeling (BSEM) where grandparental investment in grandchildren was modelled using multi-indicator unobserved latent variable. Our results showed that maternal grandmothers' investment was increased by having a living maternal grandfather but not vice versa. Having a living maternal grandmother was also associated with decreased investment of paternal grandparents while the opposite was not found. These findings indicate that the association between the survival status of other grandparents and the focal grandparents' investment varies between grandparent types.}, } @article {pmid35984547, year = {2022}, author = {Grof-Tisza, P and Kruizenga, N and Tervahauta, AI and Blande, JD}, title = {Volatile-Mediated Induced and Passively Acquired Resistance in Sagebrush (Artemisia tridentata).}, journal = {Journal of chemical ecology}, volume = {48}, number = {9-10}, pages = {730-745}, pmid = {35984547}, issn = {1573-1561}, support = {797898//HORIZON EUROPE Marie Sklodowska-Curie Actions/ ; 309425//Academy of Finland/ ; }, mesh = {Humans ; *Artemisia/physiology ; Herbivory/physiology ; *Volatile Organic Compounds/pharmacology/metabolism ; Plants/metabolism ; }, abstract = {Plants produce a diversity of secondary metabolites including volatile organic compounds. Some species show discrete variation in these volatile compounds such that individuals within a population can be grouped into distinct chemotypes. A few studies reported that volatile-mediated induced resistance is more effective between plants belonging to the same chemotype and that chemotypes are heritable. The authors concluded that the ability of plants to differentially respond to cues from related individuals that share the same chemotype is a form of kin recognition. These studies assumed plants were actively responding but did not test the mechanism of resistance. A similar result was possible through the passive adsorption and reemission of repellent or toxic VOCs by plants exposed to damage-induced plant volatiles (DIPVs). Here we conducted exposure experiments with five chemotypes of sagebrush in growth chambers; undamaged receiver plants were exposed to either filtered air or DIPVs from mechanically wounded branches. Receiver plants exposed to DIPVs experienced less herbivore damage, which was correlated with increased expression of genes involved in plant defense as well as increased emission of repellent VOCs. Plants belonging to two of the five chemotypes exhibited stronger resistance when exposed to DIPVs from plants of the same chemotypes compared to when DIPVs were from plants of a different chemotype. Moreover, some plants passively absorbed DIPVs and reemitted them, potentially conferring associational resistance. These findings support previous work demonstrating that sagebrush plants actively responded to alarm cues and that the strength of their response was dependent on the chemotypes of the plants involved. This study provides further support for kin recognition in plants but also identified volatile-mediated associational resistance as a passively acquired additional defense mechanism in sagebrush.}, } @article {pmid35925423, year = {2022}, author = {Berman, CM}, title = {Monkey business: A girl's once strange dream.}, journal = {Primates; journal of primatology}, volume = {63}, number = {5}, pages = {463-481}, pmid = {35925423}, issn = {1610-7365}, mesh = {Animals ; *Commerce ; Female ; Humans ; Macaca mulatta ; Male ; Social Behavior ; *Social Dominance ; }, abstract = {For close to 50 years, my research has focused on social relationships and social structure, particularly in macaques, and has been marked by a gradual broadening of scope. Supported by open-minded parents, I followed a once unconventional path into field primatology largely by ignoring distinct gender-based ideas about appropriate occupations for women that were prevalent when I was a child. Later, as Robert Hinde's PhD advisee, I benefited enormously from his mentoring and from the transformative experience he provided. I began by examining infant social development in free-ranging rhesus monkeys and the integration of infants into the kinship and dominance structures of their groups. I gradually branched out to look at (1) kinship and dominance in additional age classes and macaque species, (2) additional aspects of social structure (reciprocity, agonistic support, tolerance, cooperation, conflict management), (3) mechanisms and organizing principles (e.g., attraction to kin and high rank, intergenerational transmission, demography, reciprocity, social style, time constraints) and (4) evolutionary underpinnings of social relationships and structure (e.g., parental investment, kin selection, socioecology, phylogeny, biological markets). For much of this journey, I have been accompanied by talented PhD students who have enriched my experience and whom I am now proud to call colleagues and friends. It is gratifying to realize that my career choice is no longer considered as unconventional as it once was.}, } @article {pmid35920026, year = {2022}, author = {Chokechaipaisarn, C and Gardner, A}, title = {Density-dependent dispersal promotes female-biased sex allocation in viscous populations.}, journal = {Biology letters}, volume = {18}, number = {8}, pages = {20220205}, pmid = {35920026}, issn = {1744-957X}, support = {771387/ERC_/European Research Council/International ; }, mesh = {*Biological Evolution ; Female ; Humans ; Population Density ; *Sex Ratio ; Viscosity ; }, abstract = {A surprising result emerging from the theory of sex allocation is that the optimal sex ratio is predicted to be completely independent of the rate of dispersal. This striking invariance result has stimulated a huge amount of theoretical and empirical attention in the social evolution literature. However, this sex-allocation invariant has been derived under the assumption that an individual's dispersal behaviour is not modulated by population density. Here, we investigate how density-dependent dispersal shapes patterns of sex allocation in a viscous-population setting. Specifically, we find that if individuals are able to adjust their dispersal behaviour according to local population density, then they are favoured to do so, and this drives the evolution of female-biased sex allocation. This result obtains because, whereas under density-independent dispersal, population viscosity is associated not only with higher relatedness-which promotes female bias-but also with higher kin competition-which inhibits female bias-under density-dependent dispersal, the kin-competition consequences of a female-biased sex ratio are entirely abolished. We derive analytical results for the full range of group sizes and costs of dispersal, under haploid, diploid and haplodiploid modes of inheritance. These results show that population viscosity promotes female-biased sex ratios in the context of density-dependent dispersal.}, } @article {pmid35902334, year = {2022}, author = {Hitchcock, TJ and Gardner, A}, title = {Paternal genome elimination promotes altruism in viscous populations.}, journal = {Evolution; international journal of organic evolution}, volume = {76}, number = {9}, pages = {2191-2198}, pmid = {35902334}, issn = {1558-5646}, mesh = {Female ; Male ; *Altruism ; *Biological Evolution ; Haploidy ; Viscosity ; Animals ; }, abstract = {Population viscosity has long been thought to promote the evolution of altruism. However, in the simplest scenarios, the potential for altruism is invariant with respect to dispersal-a surprising result that holds for haploidy, diploidy, and haplodiploidy (arrhenotoky). Here, we develop a kin-selection model to investigate how population viscosity affects the potential for altruism in species with male paternal genome elimination (PGE), exploring altruism enacted by both females and males, and both juveniles and adults. We find that (1) PGE promotes altruistic behaviors relative to the other inheritance systems, and to a degree that depends on the extent of paternal genome expression. (2) Under PGE, dispersal increases the potential for altruism in juveniles and decreases it in adults. (3) The genetics of PGE can lead to striking differences in sex-specific potentials for altruism, even in the absence of any sex differences in ecology.}, } @article {pmid35782010, year = {2022}, author = {Fréville, H and Montazeaud, G and Forst, E and David, J and Papa, R and Tenaillon, MI}, title = {Shift in beneficial interactions during crop evolution.}, journal = {Evolutionary applications}, volume = {15}, number = {6}, pages = {905-918}, pmid = {35782010}, issn = {1752-4571}, abstract = {Plant domestication can be viewed as a form of co-evolved interspecific mutualism between humans and crops for the benefit of the two partners. Here, we ask how this plant-human mutualism has, in turn, impacted beneficial interactions within crop species, between crop species, and between crops and their associated microbial partners. We focus on beneficial interactions resulting from three main mechanisms that can be promoted by manipulating genetic diversity in agrosystems: niche partitioning, facilitation, and kin selection. We show that a combination of factors has impacted either directly or indirectly plant-plant interactions during domestication and breeding, with a trend toward reduced benefits arising from niche partitioning and facilitation. Such factors include marked decrease of molecular and functional diversity of crops and other organisms present in the agroecosystem, mass selection, and increased use of chemical inputs. For example, the latter has likely contributed to the relaxation of selection pressures on nutrient-mobilizing traits such as those associated to root exudation and plant nutrient exchanges via microbial partners. In contrast, we show that beneficial interactions arising from kin selection have likely been promoted since the advent of modern breeding. We highlight several issues that need further investigation such as whether crop phenotypic plasticity has evolved and could trigger beneficial interactions in crops, and whether human-mediated selection has impacted cooperation via kin recognition. Finally, we discuss how plant breeding and agricultural practices can help promoting beneficial interactions within and between species in the context of agroecology where the mobilization of diversity and complexity of crop interactions is viewed as a keystone of agroecosystem sustainability.}, } @article {pmid35730152, year = {2022}, author = {Micheletti, AJC and Ge, E and Zhou, L and Chen, Y and Zhang, H and Du, J and Mace, R}, title = {Religious celibacy brings inclusive fitness benefits.}, journal = {Proceedings. Biological sciences}, volume = {289}, number = {1977}, pages = {20220965}, pmid = {35730152}, issn = {1471-2954}, mesh = {Child ; China ; *Family ; Genetic Fitness ; Humans ; Male ; Reproduction ; *Sexual Abstinence ; Siblings ; }, abstract = {The influence of inclusive fitness interests on the evolution of human institutions remains unclear. Religious celibacy constitutes an especially puzzling institution, often deemed maladaptive. Here, we present sociodemographic data from an agropastoralist Buddhist population in western China, where parents sometimes sent a son to the monastery. We find that men with a monk brother father more children, and grandparents with a monk son have more grandchildren, suggesting that the practice is adaptive. We develop a model of celibacy to elucidate the inclusive fitness costs and benefits associated with this behaviour. We show that a minority of sons being celibate can be favoured if this increases their brothers' reproductive success, but only if the decision is under parental, rather than individual, control. These conditions apply to monks in our study site. Inclusive fitness considerations appear to play a key role in shaping parental preferences to adopt this cultural practice.}, } @article {pmid35703047, year = {2022}, author = {Hearn, LR and Davies, OK and Schwarz, MP}, title = {Extreme reproductive skew at the dawn of sociality is consistent with inclusive fitness theory but problematic for routes to eusociality.}, journal = {Proceedings. Biological sciences}, volume = {289}, number = {1976}, pages = {20220652}, pmid = {35703047}, issn = {1471-2954}, mesh = {Animals ; Bees ; Biological Evolution ; Female ; Humans ; Male ; Pregnancy ; *Reproduction ; *Social Behavior ; Symbiosis ; }, abstract = {To understand the earliest stages of social evolution, we need to identify species that are undergoing the initial steps into sociality. Amphylaeus morosus is the only unambiguously known social species in the bee family Colletidae and represents an independent origin of sociality within the Apoidea. This allows us to investigate the selective factors promoting the transition from solitary to social nesting. Using genome-wide SNP genotyping, we infer robust pedigree relationships to identify maternity of brood and intracolony relatedness for colonies at the end of the reproductive season. We show that A. morosus forms both matrifilial and full-sibling colonies, both involving complete or almost complete monopolization over reproduction. In social colonies, the reproductive primary was also the primary forager with the secondary female remaining in the nest, presumably as a guard. Social nesting provided significant protection against parasitism and increased brood survivorship in general. We show that secondary females gain large indirect fitness benefits from defensive outcomes, enough to satisfy the conditions of inclusive fitness theory, despite an over-production of males in social colonies. These results suggest an avenue to sociality that involves high relatedness and, very surprisingly, extreme reproductive skew in its earliest stages and raises important questions about the evolutionary steps in pathways to eusociality.}, } @article {pmid35622922, year = {2022}, author = {García-Ruiz, I and Quiñones, A and Taborsky, M}, title = {The evolution of cooperative breeding by direct and indirect fitness effects.}, journal = {Science advances}, volume = {8}, number = {21}, pages = {eabl7853}, pmid = {35622922}, issn = {2375-2548}, abstract = {The evolution of cooperative breeding has been traditionally attributed to the effect of kin selection. While there is increasing empirical evidence that direct fitness benefits are relevant, the relative importance of alternative selection mechanisms is largely obscure. Here, we model the coevolution of the cornerstones of cooperative breeding, delayed dispersal, and alloparental care, across different ecological scenarios while allowing individuals to adjust philopatry and helping levels. Our results suggest that (i) direct fitness benefits from grouping are the main driver for the evolution of philopatry; (ii) kin selection is mainly responsible for the emergence of alloparental care, but group augmentation can be a sufficient promoter in harsh environments; (iii) the coevolution of philopatry and alloparental care is subject to positive feedback; and (iv) age-dependent dispersal is triggered by both group benefits and relatedness. Model predictions are supported by empirical data and provide good opportunities for comparative analyses and experimental tests of causality.}, } @article {pmid35592877, year = {2022}, author = {Fouilloux, CA and Fromhage, L and Valkonen, JK and Rojas, B}, title = {Size-dependent aggression towards kin in a cannibalistic species.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {33}, number = {3}, pages = {582-591}, pmid = {35592877}, issn = {1045-2249}, abstract = {In juveniles extreme intraspecies aggression can seem counter-intuitive, as it might endanger their developmental goal of surviving until reproductive stage. Ultimately, aggression can be vital for survival, although the factors (e.g., genetic or environmental) leading to the expression and intensity of this behavior vary across taxa. Attacking (and sometimes killing) related individuals may reduce inclusive fitness; as a solution to this problem, some species exhibit kin discrimination and preferentially attack unrelated individuals. Here, we used both experimental and modeling approaches to consider how physical traits (e.g., size in relation to opponent) and genetic relatedness mediate aggression in dyads of cannibalistic Dendrobates tinctorius tadpoles. We paired full-sibling, half-sibling, and non-sibling tadpoles of different sizes together in an arena and recorded their aggression and activity. We found that the interaction between relative size and relatedness predicts aggressive behavior: large individuals in non-sibling dyads are significantly more aggressive than large individuals in sibling dyads. Unexpectedly, although siblings tended to attack less overall, in size-mismatched pairs they attacked faster than in non-sibling treatments. Using a theoretical model to complement these empirical findings, we propose that larval aggression reflects a balance between relatedness and size where individuals trade-off their own fitness with that of their relatives. Lay SummaryBefore you eat someone, you have to attack them first. Here, we investigated the factors that shape aggression in the cannibalistic tadpoles of the dyeing poison frog. We find that aggression depends on both size and relatedness: when set in pairs, large tadpoles are half as aggressive towards their smaller siblings than to nonsibs. It looks like belonging to the same family provides some protection against aggression, though no one is ever truly safe.}, } @article {pmid35560232, year = {2022}, author = {Roper, M and Sturrock, NJ and Hatchwell, BJ and Green, JP}, title = {Individual variation explains ageing patterns in a cooperatively breeding bird, the long-tailed tit Aegithalos caudatus.}, journal = {The Journal of animal ecology}, volume = {91}, number = {7}, pages = {1521-1534}, pmid = {35560232}, issn = {1365-2656}, support = {NE/I027118/1//Natural Environment Research Council/ ; NE/R001669/1//Natural Environment Research Council/ ; BB/M011224/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Aging/physiology ; Animals ; Cooperative Behavior ; Longevity ; Reproduction ; *Songbirds/growth & development ; }, abstract = {Alloparental care in cooperatively breeding species may alter breeder age-specific survival and reproduction and subsequently senescence. The helping behaviour itself might also undergo age-related change, and decisions to help in facultative cooperative breeders are likely to be affected by individual condition. Helpers in long-tailed tits Aegithalos caudatus assist relatives after failing to raise their own brood, with offspring from helped nests being more likely to recruit into the breeding population. Using data collected over 25 years, we examined the age trajectories of survival and reproduction in adult long-tailed tits to determine how these were affected by the presence or absence of helpers and how helper behaviour changed with age. There was evidence for increased reproductive performance with breeder age, but no effect of age on the probability of survival. We found no evidence of significant senescent decline in survival or reproductive performance, although individuals accrued less inclusive fitness in their last year of life. Lifetime reproductive success was positively related to both reproductive life span and body mass. Within a season, breeders that were assisted by helpers enjoyed greater reproductive success through enhanced offspring recruitment in the following year. We found no evidence that age affected an individual's propensity to help, or the amount of indirect fitness accrued through helping. We found a positive correlation between life span and multiple components of reproductive success, suggesting that individual variation in quality underpins age-related variation in fitness in this species. Helping decisions are driven by condition, and lifetime inclusive fitness of immigrants was predicted by body mass. These findings further support individual heterogeneity in quality being a major driver for fitness gains across the life course of long-tailed tits.}, } @article {pmid35440705, year = {2022}, author = {Tuominen, LS and Helle, S and Helanterä, H and Karell, P and Rapeli, L and Richmond, D and Vuorisalo, T and Brommer, JE}, title = {Structural equation modeling reveals decoupling of ecological and self-perceived outcomes in a garden box social-ecological system.}, journal = {Scientific reports}, volume = {12}, number = {1}, pages = {6425}, pmid = {35440705}, issn = {2045-2322}, mesh = {Ecosystem ; *Gardening ; *Gardens ; Latent Class Analysis ; Social Environment ; }, abstract = {It is well known that green urban commons enhance mental and physical well-being and improve local biodiversity. We aim to investigate how these outcomes are related in an urban system and which variables are associated with better outcomes. We model the outcomes of an urban common-box gardening-by applying the Social-Ecological Systems (SES) framework. We expand the SES framework by analyzing it from the perspective of social evolution theory. The system was studied empirically through field inventories and questionnaires and modeled quantitatively by Structural Equation Modeling (SEM). This method offers powerful statistical models of complex social-ecological systems. Our results show that objectively evaluated ecological outcomes and self-perceived outcomes are decoupled: gardening groups that successfully govern the natural resource ecologically do not necessarily report many social, ecological, or individual benefits, and vice versa. Social capital, box location, gardener concerns, and starting year influenced the changes in the outcomes. In addition, the positive association of frequent interactions with higher self-perceived outcomes, and lack of such association with relatedness of group members suggests that reciprocity rather than kin selection explains cooperation. Our findings exemplify the importance of understanding natural resource systems at a very low "grassroot" level.}, } @article {pmid35432938, year = {2022}, author = {Marquez-Rosado, A and Garcia-Co, C and Londoño-Nieto, C and Carazo, P}, title = {No evidence that relatedness or familiarity modulates male harm in Drosophila melanogaster flies from a wild population.}, journal = {Ecology and evolution}, volume = {12}, number = {4}, pages = {e8803}, pmid = {35432938}, issn = {2045-7758}, abstract = {Sexual selection frequently promotes the evolution of aggressive behaviors that help males compete against their rivals, but which may harm females and hamper their fitness. Kin selection theory predicts that optimal male-male competition levels can be reduced when competitors are more genetically related to each other than to the population average, contributing to resolve this sexual conflict. Work in Drosophila melanogaster has spearheaded empirical tests of this idea, but studies so far have been conducted in laboratory-adapted populations in homogeneous rearing environments that may hamper kin recognition, and used highly skewed sex ratios that may fail to reflect average natural conditions. Here, we performed a fully factorial design with the aim of exploring how rearing environment (i.e., familiarity) and relatedness affect male-male aggression, male harassment, and overall male harm levels in flies from a wild population of Drosophila melanogaster, under more natural conditions. Namely, we (a) manipulated relatedness and familiarity so that larvae reared apart were raised in different environments, as is common in the wild, and (b) studied the effects of relatedness and familiarity under average levels of male-male competition in the field. We show that, contrary to previous findings, groups of unrelated-unfamiliar males were as likely to fight with each other and harass females than related-familiar males and that overall levels of male harm to females were similar across treatments. Our results suggest that the role of kin selection in modulating sexual conflict is yet unclear in Drosophila melanogaster, and call for further studies that focus on natural populations and realistic socio-sexual and ecological environments.}, } @article {pmid35429546, year = {2022}, author = {Taylor, JH and Grieb, ZA}, title = {Species differences in the effect of oxytocin on maternal behavior: A model incorporating the potential for allomaternal contributions.}, journal = {Frontiers in neuroendocrinology}, volume = {65}, number = {}, pages = {100996}, doi = {10.1016/j.yfrne.2022.100996}, pmid = {35429546}, issn = {1095-6808}, mesh = {Animals ; Female ; Humans ; Mammals ; *Maternal Behavior ; Mothers ; *Oxytocin ; Receptors, Oxytocin ; Species Specificity ; }, abstract = {Oxytocin has historically been linked to processes involved with maternal behavior. However, the relative importance of oxytocin for maternal behavior widely varies among mammalian species, from indispensable to apparently nonessential. This review proposes a new model in which the relative importance of oxytocin for mothering across species is explained by an evolutionary pressure which we term "allomaternal potential", or the degree to which other conspecifics are capable and likely to assist with caregiving. It is notable that in animals where allomaternal potential is high (i.e., many quality helpers are available), oxytocin is decoupled from mothering. However, in animals where allomaternal potential is low (i.e., conspecifics refuse to, or do not provide, quality help), oxytocin is crucial for mothering. We posit that this relationship is a form of kin selection, whereby oxytocin is a signal that leads mothers to preferentially dispense resources to their own young when quality helpers are unlikely.}, } @article {pmid35412899, year = {2022}, author = {Levy, M and Lo, AW}, title = {Hamilton's rule in economic decision-making.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {16}, pages = {e2108590119}, pmid = {35412899}, issn = {1091-6490}, mesh = {*Altruism ; *Biological Evolution ; Decision Making ; Economics, Behavioral ; Humans ; *Selection, Genetic ; }, abstract = {Hamilton’s rule [W. D. Hamilton, Am. Nat. 97, 354–356 (1963); W. D. Hamilton, J. Theor. Biol. 7, 17–52 (1964)] quantifies the central evolutionary ideas of inclusive fitness and kin selection into a simple algebraic relationship. Evidence consistent with Hamilton’s rule is found in many animal species. A drawback of investigating Hamilton’s rule in these species is that one can estimate whether a given behavior is consistent with the rule, but a direct examination of the exact cutoff for altruistic behavior predicted by Hamilton is almost impossible. However, to the degree that economic resources confer survival benefits in modern society, Hamilton’s rule may be applicable to economic decision-making, in which case techniques from experimental economics offer a way to determine this cutoff. We employ these techniques to examine whether Hamilton’s rule holds in human decision-making, by measuring the dependence between an experimental subject’s maximal willingness to pay for a gift of $50 to be given to someone else and the genetic relatedness of the subject to the gift’s recipient. We find good agreement with the predictions of Hamilton’s rule. Moreover, regression analysis of the willingness to pay versus genetic relatedness, the number of years living in the same residence, age, and sex shows that almost all the variation is explained by genetic relatedness. Similar but weaker results are obtained from hypothetical questions regarding the maximal risk to her own life that the subject is willing to take in order to save the recipient’s life.}, } @article {pmid35398139, year = {2022}, author = {Straub, L and Strobl, V and Bruckner, S and Camenzind, DW and Van Oystaeyen, A and Wäckers, F and Williams, GR and Neumann, P}, title = {Buffered fitness components: Antagonism between malnutrition and an insecticide in bumble bees.}, journal = {The Science of the total environment}, volume = {833}, number = {}, pages = {155098}, doi = {10.1016/j.scitotenv.2022.155098}, pmid = {35398139}, issn = {1879-1026}, mesh = {Animals ; Bees ; Insecta ; *Insecticides/toxicity ; Male ; *Malnutrition ; Reproduction ; Spermatozoa ; }, abstract = {Global insect biodiversity declines due to reduced fitness are linked to interactions between environmental stressors. In social insects, inclusive fitness depends on successful mating of reproductives, i.e. males and queens, and efficient collaborative brood care by workers. Therefore, interactive effects between malnutrition and environmental pollution on sperm and feeding glands (hypopharyngeal glands (HPGs)) would provide mechanisms for population declines, unless buffered against due to their fitness relevance. However, while negative effects for bumble bee colony fitness are known, the effects of malnutrition and insecticide exposure singly and in combination on individuals are poorly understood. Here we show, in a fully-crossed laboratory experiment, that malnutrition and insecticide exposure result in neutral or antagonistic interactions for spermatozoa and HPGs of bumble bees, Bombus terrestris, suggesting strong selection to buffer key colony fitness components. No significant effects were observed for mortality and consumption, but significant negative effects were revealed for spermatozoa traits and HPGs. The combined effects on these parameters were not higher than the individual stressor effects, which indicates an antagonistic interaction between both. Despite the clear potential for additive effects, due to the individual stressors impairing muscle quality and neurological control, simultaneous malnutrition and insecticide exposure surprisingly did not reveal an increased impact compared to individual stressors, probably due to key fitness traits being resilient. Our data support that stressor interactions require empirical tests on a case-by-case basis and need to be regarded in context to understand underlying mechanisms and so adequately mitigate the ongoing decline of the entomofauna.}, } @article {pmid35369745, year = {2022}, author = {Mullon, C and Lehmann, L}, title = {Evolution of warfare by resource raiding favours polymorphism in belligerence and bravery.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {377}, number = {1851}, pages = {20210136}, pmid = {35369745}, issn = {1471-2970}, mesh = {Aggression ; Animals ; *Courage ; Phenotype ; Polymorphism, Genetic ; Warfare ; }, abstract = {From protists to primates, intergroup aggression and warfare over resources have been observed in several taxa whose populations typically consist of groups connected by limited genetic mixing. Here, we model the coevolution between four traits relevant to this setting: (i) investment into common-pool resource production within groups (helping); (ii) proclivity to raid other groups to appropriate their resources (belligerence); and investments into (iii) defense and (iv) offense of group contests (defensive and offensive bravery). We show that when traits coevolve, the population often experiences disruptive selection favouring two morphs: 'Hawks', who express high levels of both belligerence and offensive bravery; and 'Doves', who express neither. This social polymorphism involves further among-traits associations when the fitness costs of helping and bravery interact. In particular, if helping is antagonistic with both forms of bravery, coevolution leads to the coexistence of individuals that either: (i) do not participate into common-pool resource production but only in its defense and appropriation (Scrounger Hawks) or (ii) only invest into common pool resource production (Producer Doves). Provided groups are not randomly mixed, these findings are robust to several modelling assumptions. This suggests that inter-group aggression is a potent mechanism in favouring within-group social diversity and behavioural syndromes. This article is part of the theme issue 'Intergroup conflict across taxa'.}, } @article {pmid35369743, year = {2022}, author = {Rodrigues, AMM and Barker, JL and Robinson, EJH}, title = {From inter-group conflict to inter-group cooperation: insights from social insects.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {377}, number = {1851}, pages = {20210466}, pmid = {35369743}, issn = {1471-2970}, mesh = {Aggression ; Animals ; *Group Processes ; Humans ; *Insecta ; Problem Solving ; }, abstract = {The conflict between social groups is widespread, often imposing significant costs across multiple groups. The social insects make an ideal system for investigating inter-group relationships, because their interaction types span the full harming-helping continuum, from aggressive conflict, to mutual tolerance, to cooperation between spatially separate groups. Here we review inter-group conflict in the social insects and the various means by which they reduce the costs of conflict, including individual or colony-level avoidance, ritualistic behaviours and even group fusion. At the opposite extreme of the harming-helping continuum, social insect groups may peacefully exchange resources and thus cooperate between groups in a manner rare outside human societies. We discuss the role of population viscosity in favouring inter-group cooperation. We present a model encompassing intra- and inter-group interactions, and local and long-distance dispersal. We show that in this multi-level population structure, the increased likelihood of cooperative partners being kin is balanced by increased kin competition, such that neither cooperation (helping) nor conflict (harming) is favoured. This model provides a baseline context in which other intra- and inter-group processes act, tipping the balance toward or away from conflict. We discuss future directions for research into the ecological factors shaping the evolution of inter-group interactions. This article is part of the theme issue 'Intergroup conflict across taxa'.}, } @article {pmid35356586, year = {2022}, author = {Scheiner, SM and Barfield, M and Holt, RD}, title = {The factors that favor adaptive habitat construction versus non-adaptive environmental conditioning.}, journal = {Ecology and evolution}, volume = {12}, number = {3}, pages = {e8763}, pmid = {35356586}, issn = {2045-7758}, abstract = {Adaptive habitat construction is a process by which individuals alter their environment so as to increase their (inclusive) fitness. Such alterations are a subset of the myriad ways that individuals condition their environment. We present an individual-based model of habitat construction to explore what factors might favor selection when the benefits of environmental alterations are shared by individuals of the same species. Our results confirm the predictions of inclusive fitness and group selection theory and expectations based on previous models that construction will be more favored when its benefits are more likely to be directed to self or near kin. We found that temporal variation had no effect on the evolution of construction. For spatial heterogeneity, construction was disfavored when the spatial pattern of movement did not match the spatial pattern of environmental heterogeneity, especially when there was spatial heterogeneity in the optimal amount of construction. Under those conditions, very strong selection was necessary to favor genetic differentiation of construction propensity among demes. We put forth a constitutive theory for the evolution of adaptive habitat construction that unifies our model with previous verbal and quantitative models into a formal conceptual framework.}, } @article {pmid35323522, year = {2022}, author = {Radford, JM and Chen, D and Chernyshova, AM and Taylor, C and Guoth, AW and Wu, T and Hill, KA and Thompson, GJ}, title = {Differential Selection on Caste-Associated Genes in a Subterranean Termite.}, journal = {Insects}, volume = {13}, number = {3}, pages = {}, pmid = {35323522}, issn = {2075-4450}, support = {RGPIN-2020-05647//Natural Sciences and Engineering Research Council/ ; }, abstract = {Analyzing the information-rich content of RNA can help uncover genetic events associated with social insect castes or other social polymorphisms. Here, we exploit a series of cDNA libraries previously derived from whole-body tissue of different castes as well as from three behaviourally distinct populations of the Eastern subterranean termite Reticulitermes flavipes. We found that the number (~0.5 M) of single nucleotide variants (SNVs) was roughly equal between nymph, worker and soldier caste libraries, but dN/dS (ratio of nonsynonymous to synonymous substitutions) analysis suggested that some of these variants confer a caste-specific advantage. Specifically, the dN/dS ratio was high (~4.3) for genes expressed in the defensively specialized soldier caste, relative to genes expressed by other castes (~1.7−1.8) and regardless of the North American population (Toronto, Raleigh, Boston) from which the castes were sampled. The populations, meanwhile, did show a large difference in SNV count but not in the manner expected from known demographic and behavioural differences; the highly invasive unicolonial population from Toronto was not the least diverse and did not show any other unique substitution patterns, suggesting any past bottleneck associated with invasion or with current unicoloniality has become obscured at the RNA level. Our study raises two important hypotheses relevant to termite sociobiology. First, the positive selection (dN/dS > 1) inferred for soldier-biased genes is presumably indirect and of the type mediated through kin selection, and second, the behavioural changes that accompany some social insect urban invasions (i.e., ‘unicoloniality’) may be detached from the loss-of-diversity expected from invasion bottlenecks.}, } @article {pmid35259982, year = {2022}, author = {Kanwal, J and Gardner, A}, title = {Population viscosity promotes altruism under density-dependent dispersal.}, journal = {Proceedings. Biological sciences}, volume = {289}, number = {1970}, pages = {20212668}, pmid = {35259982}, issn = {1471-2954}, mesh = {*Altruism ; *Biological Evolution ; Female ; Humans ; Parturition ; Population Dynamics ; Pregnancy ; Selection, Genetic ; Viscosity ; }, abstract = {A basic mechanism of kin selection is population viscosity, whereby individuals do not move far from their place of birth and hence tend to be surrounded by relatives. In such circumstances, even indiscriminate altruism among neighbours will often involve interactions between kin, which has a promoting effect on the evolution of altruism. This has the potential to explain altruistic behaviour across the whole tree of life, including in taxa for which recognition of kin is implausible. However, population viscosity may also intensify resource competition among kin, which has an inhibitory effect on altruism. Indeed, in the simplest scenario, in which individuals disperse with a fixed probability, these two effects have been shown to exactly cancel such that there is no net impact of viscosity on altruism. Here, we show that if individuals are able to disperse conditionally upon local density, they are favoured to do so, with more altruistic neighbourhoods exhibiting a higher rate of dispersal and concomitant relaxation of kin competition. Comparing across different populations or species, this leads to a negative correlation between overall levels of dispersal and altruism. We demonstrate both analytically and using individual-based simulations that population viscosity promotes the evolution of altruism under density-dependent dispersal.}, } @article {pmid35253258, year = {2022}, author = {Lerdau, M}, title = {The complicated legacy of E. O. Wilson with respect to genetics and human behavior.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {44}, number = {5}, pages = {e2200034}, doi = {10.1002/bies.202200034}, pmid = {35253258}, issn = {1521-1878}, mesh = {*Behavior ; Humans ; *Selection, Genetic ; }, abstract = {Over the arc of his career, E. O. Wilson first embraced, then popularized, and finally rejected an extreme genetical hereditarian view of human nature. The controversy that ensued during the period of popularization (largely in the 1970s and 1980s) obscured the fact that empirical and theoretical research during this time undercut the assumptions necessary for this view. By the end of his career, Wilson accepted the fact that individual/kin selection models were insufficient to explain human behavior and society, and he began conducting research based upon multilevel (group) selection, an idea he had previously scorned.}, } @article {pmid35222785, year = {2022}, author = {Maley, CC and Seyedi, S}, title = {The life history theory of the Lord of the Rings: a randomized controlled trial of using fact versus fiction to teach life history theory.}, journal = {Evolution}, volume = {15}, number = {1}, pages = {2}, pmid = {35222785}, issn = {1936-6426}, abstract = {UNLABELLED: Does asking students to apply concepts from evolution to a fictional context, compared to a novel biological context, improve their understanding, exam performance or enjoyment of the material? Or does it harm their education by taking time away from true biology? At our institution, we sometimes ask students to apply life history theory to species from fictional movies, television shows or books. Previously, we had used a factual article on life history theory, to supplement our textbook. We wrote an alternative introduction to life history theory (included in the additional files for educational use), using Tolkien's fictional species from his Lord of the Rings books. We also introduce the biological species definition, sexual selection, sexual dimorphism, kin selection, and the handicap principle, as those concepts arose naturally in the discussion of the fictional species. Life history theory predicts strong correlations between traits affecting reproduction, growth and survival, which are all shaped by the ecology of the species. Thus, we can teach life history theory by asking students to infer traits and aspects of the ecology of a fictional species that have never been described, based on the partial information included in the fictional sources. In a large, third year undergraduate evolution course at Arizona State University, we randomized 16 tutorial sections of a total of 264 students to either read our article on the life history theory of Lord of the Rings, or the factual article we had used previously in the course. We found that the exam performance on life history questions for the two groups were almost identical, except that fans of The Lord of the Rings who had read our article did better on the exam. Enjoyment, engagement and interest in life history theory was approximately a full point higher on a 5-point Likert scale for the students that had read the fictional article, and was highly statistically significantly different (T-test p < 0.001 for all questions). There was no difference between the two groups in their familiarity or enjoyment of The Lord of the Rings stories themselves. Reading the article that taught life history theory by applying it to the species of The Lord of the Rings neither helped nor harmed exam performance, but did significantly improve student enjoyment, engagement and interest in life history theory, and even improved exam scores in students who liked The Lord of the Rings. Using fiction to teach science may also help to engage non-traditional students, such as world-builders, outside of our institutions of education. By encouraging students to apply the scientific ideas to their favorite stories from their own cultures, we may be able to improve both inclusivity and education.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12052-022-00160-8.}, } @article {pmid35196086, year = {2022}, author = {Shah, SS and Rubenstein, DR}, title = {Prenatal environmental conditions underlie alternative reproductive tactics that drive the formation of a mixed-kin cooperative society.}, journal = {Science advances}, volume = {8}, number = {8}, pages = {eabk2220}, pmid = {35196086}, issn = {2375-2548}, abstract = {Although animal societies often evolve due to limited natal dispersal that results in kin clustering and facilitates cooperation among relatives, many species form cooperative groups with low kin structure. These groups often comprise residents and immigrants of the same sex that compete for breeding opportunities. To understand how these mixed-kin societies form, we investigated the causes and fitness consequences of dispersal decisions in male cooperatively breeding superb starlings (Lamprotornis superbus) inhabiting a climatically unpredictable environment. We show that the two alternative reproductive tactics-natal dispersal or philopatry-exhibit reproductive trade-offs resulting in equivalent lifetime inclusive fitness. Unexpectedly, an individual's tactic is related to the prenatal environment its parents experience before laying rather than the environment it experiences as a juvenile. Individuals that adopt the tactic not predicted by prenatal environmental conditions have lower fitness. Ultimately, climate-driven oscillating selection appears to stabilize mixed-kin societies despite the potential for social conflict.}, } @article {pmid35193981, year = {2022}, author = {Belcher, LJ and Dewar, AE and Ghoul, M and West, SA}, title = {Kin selection for cooperation in natural bacterial populations.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {119}, number = {9}, pages = {}, pmid = {35193981}, issn = {1091-6490}, support = {834164/ERC_/European Research Council/International ; }, mesh = {*Bacterial Physiological Phenomena ; Genes, Bacterial ; Mutation ; Pseudomonas aeruginosa/genetics ; Quorum Sensing ; }, abstract = {Bacteria produce a range of molecules that are secreted from the cell and can provide a benefit to the local population of cells. Laboratory experiments have suggested that these "public goods" molecules represent a form of cooperation, favored because they benefit closely related cells (kin selection). However, there is a relative lack of data demonstrating kin selection for cooperation in natural populations of bacteria. We used molecular population genetics to test for signatures of kin selection at the genomic level in natural populations of the opportunistic pathogen Pseudomonas aeruginosa We found consistent evidence from multiple traits that genes controlling putatively cooperative traits have higher polymorphism and greater divergence and are more likely to harbor deleterious mutations relative to genes controlling putatively private traits, which are expressed at similar rates. These patterns suggest that cooperative traits are controlled by kin selection, and we estimate that the relatedness for social interactions in P. aeruginosa is r = 0.84. More generally, our results demonstrate how molecular population genetics can be used to study the evolution of cooperation in natural populations.}, } @article {pmid35168400, year = {2022}, author = {Helle, S and Tanskanen, AO and Coall, DA and Danielsbacka, M}, title = {Matrilateral bias of grandparental investment in grandchildren persists despite the grandchildren's adverse early life experiences.}, journal = {Proceedings. Biological sciences}, volume = {289}, number = {1969}, pages = {20212574}, pmid = {35168400}, issn = {1471-2954}, mesh = {Adolescent ; Bias ; Biological Evolution ; Child ; Family ; *Grandparents ; Humans ; Intergenerational Relations ; Reproduction ; }, abstract = {Evolutionary theory predicts a downward flow of investment from older to younger generations, representing individual efforts to maximize inclusive fitness. Maternal grandparents and maternal grandmothers (MGMs) in particular consistently show the highest levels of investment (e.g. time, care and resources) in their grandchildren. Grandparental investment overall may depend on social and environmental conditions that affect the development of children and modify the benefits and costs of investment. Currently, the responses of grandparents to adverse early life experiences (AELEs) in their grandchildren are assessed from a perspective of increased investment to meet increased need. Here, we formulate an alternative prediction that AELEs may be associated with reduced grandparental investment, as they can reduce the reproductive value of the grandchildren. Moreover, we predicted that paternal grandparents react more strongly to AELEs compared to maternal grandparents because maternal kin should expend extra effort to invest in their descendants. Using population-based survey data for English and Welsh adolescents, we found evidence that the investment of maternal grandparents (MGMs in particular) in their grandchildren was unrelated to the grandchildren's AELEs, while paternal grandparents invested less in grandchildren who had experienced more AELEs. These findings seemed robust to measurement errors in AELEs and confounding due to omitted shared causes.}, } @article {pmid35154777, year = {2022}, author = {Fox, M and Wiley, KS}, title = {How a pregnant woman's relationships with her siblings relate to her mental health: a prenatal allocare perspective.}, journal = {Evolution, medicine, and public health}, volume = {10}, number = {1}, pages = {1-20}, pmid = {35154777}, issn = {2050-6201}, support = {F32 MD015201/MD/NIMHD NIH HHS/United States ; K01 DK105110/DK/NIDDK NIH HHS/United States ; P2C HD041022/HD/NICHD NIH HHS/United States ; R03 DK125524/DK/NIDDK NIH HHS/United States ; }, abstract = {BACKGROUND: In cooperatively breeding species, individuals may promote their inclusive fitness through allomothering. Humans exhibit some features of cooperative breeding, and previous studies have focused on allomothering by grandparents and juvenile siblings in the postnatal period. We hypothesize that a pregnant woman's relationships with her siblings (offspring's maternal aunts and uncles) are beneficial for maternal affect in ways that can enhance the siblings' inclusive fitness. Maternal affect during pregnancy is a salient target of allocare given the detrimental effects of antepartum mood disorders on birth and infant outcomes.

METHODOLOGY: We test our hypotheses in a cohort of pregnant Latina women in Southern California (N = 201). Predictor variables of interest include number of siblings a participant has, if she has sisters, frequency of seeing siblings, and frequency of communication with siblings. Outcome variables measuring maternal affect include depression, state anxiety, pregnancy-related anxiety and perceived stress.

RESULTS: Having at least one sister and greater frequency of communication with siblings were associated with fewer depressive symptoms during pregnancy. No significant associations were found between sibling variables and other measures of affect.

CONCLUSION AND IMPLICATIONS: Results suggest that how frequently you communicate with, and not how often you see, siblings could be protective against risk of antepartum depression. Sibling allomothering could impart effects through social-emotional support rather than instrumental support, as a strategy to benefit the prenatal environment in which future nieces and nephews develop. Allomothering may be particularly important in cultural contexts that value family relationships. Future studies should investigate other communities.}, } @article {pmid35063725, year = {2022}, author = {Roth, JD and Dobson, FS and Neuhaus, P and Abebe, A and Barra, T and Boonstra, R and Edwards, PD and Gonzalez, MA and Hammer, TL and Harscouet, E and McCaw, LK and Mann, M and Palme, R and Tissier, M and Uhlrich, P and Saraux, C and Viblanc, VA}, title = {Territorial scent-marking effects on vigilance behavior, space use, and stress in female Columbian ground squirrels.}, journal = {Hormones and behavior}, volume = {139}, number = {}, pages = {105111}, doi = {10.1016/j.yhbeh.2022.105111}, pmid = {35063725}, issn = {1095-6867}, mesh = {Animals ; Female ; Hydrocortisone ; *Lactation ; *Odorants ; Pheromones ; Sciuridae/physiology ; Territoriality ; }, abstract = {Social environments can profoundly affect the behavior and stress physiology of group-living animals. In many territorial species, territory owners advertise territorial boundaries to conspecifics by scent marking. Several studies have investigated the information that scent marks convey about donors' characteristics (e.g., dominance, age, sex, reproductive status), but less is known about whether scents affect the behavior and stress of recipients. We experimentally tested the hypothesis that scent marking may be a potent source of social stress in territorial species. We tested this hypothesis for Columbian ground squirrels (Urocitellus columbianus) during lactation, when territorial females defend individual nest-burrows against conspecifics. We exposed lactating females, on their territory, to the scent of other lactating females. Scents were either from unfamiliar females, kin relatives (a mother, daughter, or sister), or their own scent (control condition). We expected females to react strongly to novel scents from other females on their territory, displaying increased vigilance, and higher cortisol levels, indicative of behavioral and physiological stress. We further expected females to be more sensitive to unfamiliar female scents than to kin scents, given the matrilineal social structure of this species and known fitness benefits of co-breeding in female kin groups. Females were highly sensitive to intruder (both unfamiliar and kin) scents, but not to their own scent. Surprisingly, females reacted more strongly to the scent of close kin than to the scent of unfamiliar females. Vigilance behavior increased sharply in the presence of scents; this increase was more marked for kin than unfamiliar female scents, and was mirrored by a marked 131% increase in free plasma cortisol levels in the presence of kin (but not unfamiliar female) scents. Among kin scents, lactating females were more vigilant to the scent of sisters of equal age, but showed a marked 318% increase in plasma free cortisol levels in response to the scent of older and more dominant mothers. These results suggest that scent marks convey detailed information on the identity of intruders, directly affecting the stress axis of territory holders.}, } @article {pmid35000446, year = {2022}, author = {Shimoji, H and Dobata, S}, title = {The build-up of dominance hierarchies in eusocial insects.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {377}, number = {1845}, pages = {20200437}, pmid = {35000446}, issn = {1471-2970}, mesh = {Animals ; *Ants/physiology ; Behavior, Animal/physiology ; Humans ; Reproduction/physiology ; Social Dominance ; *Wasps/physiology ; }, abstract = {Reproductive division of labour is a hallmark of eusocial insects. However, its stability can often be hampered by the potential for reproduction by otherwise sterile nest-mates. Dominance hierarchy has a crucial role in some species in regulating which individuals reproduce. Compared with those in vertebrates, the dominance hierarchies in eusocial insects tend to involve many more individuals, and should require additional selective forces unique to them. Here, we provide an overview of a series of studies on dominance hierarchies in eusocial insects. Although reported from diverse eusocial taxa, dominance hierarchies have been extensively studied in paper wasps and ponerine ants. Starting from molecular physiological attributes of individuals, we describe how the emergence of dominance hierarchies can be understood as a kind of self-organizing process through individual memory and local behavioural interactions. The resulting global structures can be captured by using network analyses. Lastly, we argue the adaptive significance of dominance hierarchies from the standpoint of sterile subordinates. Kin selection, underpinned by relatedness between nest-mates, is key to the subordinates' acceptance of their positions in the hierarchies. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.}, } @article {pmid34953159, year = {2022}, author = {Walter, A and Bilde, T}, title = {Avoiding the tragedy of the commons: Improved group-feeding performance in kin groups maintains foraging cooperation in subsocial Stegodyphus africanus spiders (Araneae, Eresidae).}, journal = {Journal of evolutionary biology}, volume = {35}, number = {3}, pages = {391-399}, doi = {10.1111/jeb.13976}, pmid = {34953159}, issn = {1420-9101}, support = {624798/MCCC_/Marie Curie/United Kingdom ; }, mesh = {Animals ; *Spiders/physiology ; }, abstract = {Cooperation involving shared resource systems is prone to 'the tragedy of the commons', where individuals act in their own self-interest to exploit the resource in a manner that is detrimental to the common good of all group members. Directing cooperation towards kin provides a solution to this problem and predicts the differential performance depending on the relatedness of group members. In subsocial spiders, juveniles live in transient groups that cooperate in hunting and communal feeding. Prey capture is costly in terms of risk of injury and investment of venom and digestive enzymes, and therefore presents a situation where individuals may attempt to avoid costly interactions and exploit the resource acquired by other group members. We tested the prediction that individuals differentiate participation and/or investment in cooperative prey capture and extra-oral digestion (injection of digestive enzymes into prey prior to the initiation of extraction of nutrients) in response to the relatedness of group members with whom they interact, in the subsocial spider Stegodyphus africanus. The performance of groups and interactions over prey attack in groups of either related or mixed kin spiderlings were determined over a period of 4 weeks. We show that kin groups attack the prey significantly faster, recruit individuals to form feeding groups faster, extract prey body mass more efficiently and experience less antagonistic interactions than groups of mixed relatedness, which ultimately translates into an elevated growth rate. These results indicate that related individuals are more willing to take risks and invest in communal digestion when foraging with kin, as predicted by inclusive fitness theory as a solution to the tragedy of the commons.}, } @article {pmid34949484, year = {2022}, author = {Rodrigues, AMM and Gardner, A}, title = {Reproductive value and the evolution of altruism.}, journal = {Trends in ecology & evolution}, volume = {37}, number = {4}, pages = {346-358}, doi = {10.1016/j.tree.2021.11.007}, pmid = {34949484}, issn = {1872-8383}, support = {771387/ERC_/European Research Council/International ; }, mesh = {*Altruism ; Biological Evolution ; Female ; Humans ; Reproduction ; *Selection, Genetic ; }, abstract = {Altruism is favored by natural selection provided that it delivers sufficient benefits to relatives. An altruist's valuation of her relatives depends upon the extent to which they carry copies of her genes - relatedness - and also on the extent to which they are able to transmit their own genes to future generations - reproductive value. However, although relatedness has received a great deal of attention with regard to altruism, reproductive value has been surprisingly neglected. We review how reproductive value modulates patterns of altruism in relation to individual differences in age, sex, and general condition, and discuss how social partners may manipulate each other's reproductive value to incentivize altruism. This topic presents opportunities for tight interplay between theoretical and empirical research.}, } @article {pmid34938490, year = {2021}, author = {Humphries, DJ and Nelson-Flower, MJ and Bell, MBV and Finch, FM and Ridley, AR}, title = {Kinship, dear enemies, and costly combat: The effects of relatedness on territorial overlap and aggression in a cooperative breeder.}, journal = {Ecology and evolution}, volume = {11}, number = {23}, pages = {17031-17042}, pmid = {34938490}, issn = {2045-7758}, abstract = {Many species maintain territories, but the degree of overlap between territories and the level of aggression displayed in territorial conflicts can vary widely, even within species. Greater territorial overlap may occur when neighboring territory holders are close relatives. Animals may also differentiate neighbors from strangers, with more familiar neighbors eliciting less-aggressive responses during territorial conflicts (the "dear enemy" effect). However, research is lacking in how both kinship and overlap affect territorial conflicts, especially in group-living species. Here, we investigate kinship, territorial overlap, and territorial conflict in a habituated wild population of group-living cooperatively breeding birds, the southern pied babbler Turdoides bicolor. We find that close kin neighbors are beneficial. Territories overlap more when neighboring groups are close kin, and these larger overlaps with kin confer larger territories (an effect not seen for overlaps with unrelated groups). Overall, territorial conflict is costly, causing significant decreases in body mass, but conflicts with kin are shorter than those conducted with nonkin. Conflicts with more familiar unrelated neighbors are also shorter, indicating these neighbors are "dear enemies." However, kinship modulates the "dear enemy" effect; even when kin are encountered less frequently, kin elicit less-aggressive responses, similar to the "dear enemy" effect. Kin selection appears to be a main influence on territorial behavior in this species. Groups derive kin-selected benefits from decreased conflicts and maintain larger territories when overlapping with kin, though not when overlapping with nonkin. More generally, it is possible that kinship extends the "dear enemy" effect in animal societies.}, } @article {pmid34933602, year = {2021}, author = {Hitchcock, TJ and Gardner, A}, title = {Sex-biased demography modulates male harm across the genome.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1965}, pages = {20212237}, pmid = {34933602}, issn = {1471-2954}, mesh = {Biological Evolution ; Demography ; Female ; *Genome ; Humans ; Inheritance Patterns ; Male ; Reproduction ; *Sex Chromosomes ; }, abstract = {Recent years have seen an explosion of theoretical and empirical interest in the role that kin selection plays in shaping patterns of sexual conflict, with a particular focus on male harming traits. However, this work has focused solely on autosomal genes, and as such it remains unclear how demography modulates the evolution of male harm loci occurring in other portions of the genome, such as sex chromosomes and cytoplasmic elements. To investigate this, we extend existing models of sexual conflict for application to these different modes of inheritance. We first analyse the general case, revealing how sex-specific relatedness, reproductive value and the intensity of local competition combine to determine the potential for male harm. We then analyse a series of demographically explicit models, to assess how dispersal, overlapping generations, reproductive skew and the mechanism of population regulation affect sexual conflict across the genome, and drive conflict between nuclear and cytoplasmic genes. We then explore the effects of sex biases in these demographic parameters, showing how they may drive further conflicts between autosomes and sex chromosomes. Finally, we outline how different crossing schemes may be used to identify signatures of these intragenomic conflicts.}, } @article {pmid34932965, year = {2021}, author = {Roy, SW}, title = {Sex determination: Ant supergenes link sex ratio to social structure.}, journal = {Current biology : CB}, volume = {31}, number = {24}, pages = {R1573-R1575}, doi = {10.1016/j.cub.2021.11.017}, pmid = {34932965}, issn = {1879-0445}, mesh = {Animals ; *Ants/genetics ; Reproduction ; *Sex Ratio ; Social Structure ; }, abstract = {A new study maps individual Formica ant queens' tendency to produce single-sex offspring to a so-called 'supergene' locus. This supergene neighbors another supergene determining social structure. Consequently, single-queen and multi-queen colonies disproportionately produce daughters and sons, respectively. This association mirrors the predictions of kin selection, though other possible explanations remain.}, } @article {pmid34878556, year = {2022}, author = {Brodie, ED and Cook, PA and Costello, RA and Formica, VA}, title = {Phenotypic Assortment Changes the Landscape of Selection.}, journal = {The Journal of heredity}, volume = {113}, number = {1}, pages = {91-101}, doi = {10.1093/jhered/esab062}, pmid = {34878556}, issn = {1465-7333}, mesh = {Animals ; Biological Evolution ; Body Size ; *Coleoptera/genetics ; Male ; Phenotype ; Selection, Genetic ; *Social Behavior ; }, abstract = {Social interactions with conspecifics can dramatically affect an individual's fitness. The positive or negative consequences of interacting with social partners typically depend on the value of traits that they express. These pathways of social selection connect the traits and genes expressed in some individuals to the fitness realized by others, thereby altering the total phenotypic selection on and evolutionary response of traits across the multivariate phenotype. The downstream effects of social selection are mediated by the patterns of phenotypic assortment between focal individuals and their social partners (the interactant covariance, Cij', or the multivariate form, CI). Depending on the sign and magnitude of the interactant covariance, the direction of social selection can be reinforced, reversed, or erased. We report estimates of Cij' from a variety of studies of forked fungus beetles to address the largely unexplored questions of consistency and plasticity of phenotypic assortment in natural populations. We found that phenotypic assortment of male beetles based on body size or horn length was highly variable among subpopulations, but that those differences also were broadly consistent from year to year. At the same time, the strength and direction of Cij' changed quickly in response to experimental changes in resource distribution and social properties of populations. Generally, interactant covariances were more negative in contexts in which the number of social interactions was greater in both field and experimental situations. These results suggest that patterns of phenotypic assortment could be important contributors to variability in multilevel selection through their mediation of social selection gradients.}, } @article {pmid34850889, year = {2022}, author = {McGlothlin, JW and Fisher, DN}, title = {Social Selection and the Evolution of Maladaptation.}, journal = {The Journal of heredity}, volume = {113}, number = {1}, pages = {61-68}, doi = {10.1093/jhered/esab061}, pmid = {34850889}, issn = {1465-7333}, mesh = {Adaptation, Physiological/genetics ; *Biological Evolution ; Genetic Fitness ; Phenotype ; *Selection, Genetic ; }, abstract = {Evolution by natural selection is often viewed as a process that inevitably leads to adaptation or an increase in population fitness over time. However, maladaptation, an evolved decrease in fitness, may also occur in response to natural selection under some conditions. Social selection, which arises from the effects of social partners on fitness, has been identified as a potential cause of maladaptation, but we lack a general rule identifying when social selection should lead to a decrease in population mean fitness. Here we use a quantitative genetic model to develop such a rule. We show that maladaptation is most likely to occur when social selection is strong relative to nonsocial selection and acts in an opposing direction. In this scenario, the evolution of traits that impose fitness costs on others may outweigh evolved gains in fitness for the individual, leading to a net decrease in population mean fitness. Furthermore, we find that maladaptation may also sometimes occur when phenotypes of interacting individuals negatively covary. We outline the biological situations where maladaptation in response to social selection can be expected, provide both quantitative genetic and phenotypic versions of our derived result, and suggest what empirical work would be needed to test it. We also consider the effect of social selection on inclusive fitness and support previous work showing that inclusive fitness cannot suffer an evolutionary decrease. Taken together, our results show that social selection may decrease population mean fitness when it opposes individual-level selection, even as inclusive fitness increases.}, } @article {pmid34839709, year = {2022}, author = {Domingues, CPF and Rebelo, JS and Monteiro, F and Nogueira, T and Dionisio, F}, title = {Harmful behaviour through plasmid transfer: a successful evolutionary strategy of bacteria harbouring conjugative plasmids.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {377}, number = {1842}, pages = {20200473}, pmid = {34839709}, issn = {1471-2970}, mesh = {*Bacteria/genetics ; Biological Evolution ; *Conjugation, Genetic ; Plasmids/genetics ; }, abstract = {Conjugative plasmids are extrachromosomal mobile genetic elements pervasive among bacteria. Plasmids' acquisition often lowers cells' growth rate, so their ubiquity has been a matter of debate. Chromosomes occasionally mutate, rendering plasmids cost-free. However, these compensatory mutations typically take hundreds of generations to appear after plasmid arrival. By then, it could be too late to compete with fast-growing plasmid-free cells successfully. Moreover, arriving plasmids would have to wait hundreds of generations for compensatory mutations to appear in the chromosome of their new host. We hypothesize that plasmid-donor cells may use the plasmid as a 'weapon' to compete with plasmid-free cells, particularly in structured environments. Cells already adapted to plasmids may increase their inclusive fitness through plasmid transfer to impose a cost to nearby plasmid-free cells and increase the replication opportunities of nearby relatives. A mathematical model suggests conditions under which the proposed hypothesis works, and computer simulations tested the long-term plasmid maintenance. Our hypothesis explains the maintenance of conjugative plasmids not coding for beneficial genes. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.}, } @article {pmid34821809, year = {2021}, author = {Zhao, H and Liu, Y and Zhang, H and Breeze, TD and An, J}, title = {Worker-Born Males Are Smaller but Have Similar Reproduction Ability to Queen-Born Males in Bumblebees.}, journal = {Insects}, volume = {12}, number = {11}, pages = {}, pmid = {34821809}, issn = {2075-4450}, abstract = {Queen-worker conflict over the reproduction of males exists in the majority of haplodiplioidy hymenpteran species such as bees, wasps, and ants, whose workers lose mating ability but can produce haploid males in colony. Bumblebee is one of the representatives of primitively eusocial insects with plastic division labor and belongs to monandrous and facultative low polyandry species that have reproductive totipotent workers, which are capable of competing with mother queen to produce haploid males in the queenright colony compared to higher eusocial species, e.g., honeybees. So, bumblebees should be a better material to study worker reproduction, but the reproductive characteristics of worker-born males (WMs) remain unclear. Here, we choose the best-studied bumblebee Bombus terrestris to evaluate the morphological characteristics and reproductive ability of WMs from the queenless micro-colonies. The sexually matured WMs showed smaller in forewing length and weight, relatively less sperm counts but equally high sperm viability in comparison with the queen-born males (QMs) of the queenright colony. Despite with smaller size, the WMs are able to successfully mate with the virgin queens in competition with the QMs under laboratory conditions, which is quite different from the honeybees reported. In addition, there was no difference in the colony development, including the traits such as egg-laying rate, colony establishment rate, and populations of offspring, between the WM- and the QM-mated queens. Our study highlights the equivalent reproductive ability of worker-born males compared to that of queens, which might exhibit a positive application or special use of bumblebee rearing, especially for species whose males are not enough for copulation. Further, our finding contributes new evidence to the kin selection theory and suggests worker reproduction might relate to the evolution of sociality in bees.}, } @article {pmid34803791, year = {2021}, author = {Chatterjee, D and Rai, R}, title = {Choosing Death Over Survival: A Need to Identify Evolutionary Mechanisms Underlying Human Suicide.}, journal = {Frontiers in psychology}, volume = {12}, number = {}, pages = {689022}, pmid = {34803791}, issn = {1664-1078}, abstract = {The act of killing self contradicts the central purpose of human evolution, that is, survival and propagation of one's genetic material. Yet, it continues to be one of the leading causes of human death. A handful of theories in the realm of evolutionary psychology have attempted to explain human suicide. The current article analyses the major components of certain prominent viewpoints, namely, Inclusive fitness, Bargaining model, Pain-Brain model, Psychological aposematism, and few other perspectives. The article argues that relatively more weightage has been given to understanding ultimate (the "why") rather than proximate (the "how") functionality of suicidal acts. Evolutionary theorists have consistently pointed out that to comprehensively understand a trait or behavior, one needs to delineate not only how it supports survival but also the evolution of the mechanisms underlying the trait or behavior. Existing theories on suicide have primarily focused on its fitness benefits on surviving kin instead of providing evolutionary explanations of the more complex mechanisms leading up to such self-destructive motivations. Thus, the current paper attempts to highlight this gap in theorizing while suggesting probable proximate explanations of suicide which stresses the need to diffuse attention paid to fitness consequences of the act alone. We speculate that such explorations are needed in order to build a robust and comprehensive evolutionary theory of human suicide.}, } @article {pmid34798134, year = {2022}, author = {Raymond, B and Erdos, Z}, title = {Passage and the evolution of virulence in invertebrate pathogens: Fundamental and applied perspectives.}, journal = {Journal of invertebrate pathology}, volume = {187}, number = {}, pages = {107692}, doi = {10.1016/j.jip.2021.107692}, pmid = {34798134}, issn = {1096-0805}, support = {BB/S002928/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Baculoviridae ; *Biological Evolution ; Fungi/genetics ; *Nematoda ; Virulence ; }, abstract = {Understanding the ecological and genetic factors that determine the evolution of virulence has broad value for invertebrate pathology. In addition to helping us understand the fundamental biology of our study organisms this body of theory has important applications in microbial biocontrol. Experimental tests of virulence theory are often carried out in invertebrate models and yet theory rarely informs applied passage experiments that aim to increase or maintain virulence. This review summarizes recent progress in this field with a focus on work most relevant to biological control: the virulence of invertebrate pathogens that are 'obligate killers' and which require cadavers for the production of infectious propagules. We discuss recent theory and fundamental and applied experimental evolution with bacteria, fungi, baculoviruses and nematodes. While passage experiments using baculoviruses have a long history of producing isolates with increased virulence, studies with other pathogens have not been so successful. Recent passage experiments that have applied evolution of virulence frameworks based on cooperation (kin selection) have produced novel methods and promising mutants with increased killing power. Evolution of virulence theory can provide plausible explanations for the varied results of passage experiments as well as a predictive framework for improving artificial selection.}, } @article {pmid34793823, year = {2022}, author = {Denton, KK and Ram, Y and Feldman, MW}, title = {Conformity and content-biased cultural transmission in the evolution of altruism.}, journal = {Theoretical population biology}, volume = {143}, number = {}, pages = {52-61}, doi = {10.1016/j.tpb.2021.10.004}, pmid = {34793823}, issn = {1096-0325}, mesh = {Alleles ; *Altruism ; Biological Evolution ; *Cultural Evolution ; Humans ; Phenotype ; Social Behavior ; }, abstract = {The evolution of altruism has been extensively modeled under the assumption of genetic transmission, whereas the dynamics under cultural transmission are less well understood. Previous research has shown that cultural transmission can facilitate the evolution of altruism by increasing (1) the probability of adopting the altruistic phenotype, and (2) assortment between altruists. We incorporate vertical and oblique transmission, which can be conformist or anti-conformist, into models of parental care, sibling altruism, and altruism between individuals that meet assortatively. If oblique transmission is conformist, it becomes easier for altruism to invade a population of non-altruists as the probability of vertical transmission increases. If oblique transmission is anti-conformist, decreasing vertical transmission facilitates invasion by altruism in the assortative meeting model, whereas in other models, there is a trade-off: greater vertical transmission produces greater assortment among genetically related altruists, but lowers the probability of adopting altruism via anti-conformity. Compared to conditions for invasion under genetic transmission, e.g., Hamilton's rule, we show that invasion can be easier with sufficiently strong anti-conformity, and in some models, with sufficiently high assortment even if oblique transmission is conformist. We also explore invasion by an allele A that increases individuals' content bias for altruism, in the absence of other forms of cultural transmission. If costs and benefits combine additively, A invades under previously known conditions. If costs and benefits combine multiplicatively, invasion by A and by altruism become more difficult than in the corresponding additive models.}, } @article {pmid34702072, year = {2021}, author = {Grof-Tisza, P and Karban, R and Rasheed, MU and Saunier, A and Blande, JD}, title = {Risk of herbivory negatively correlates with the diversity of volatile emissions involved in plant communication.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1961}, pages = {20211790}, pmid = {34702072}, issn = {1471-2954}, mesh = {Animals ; *Artemisia ; Herbivory ; Humans ; Insecta ; Plants ; *Volatile Organic Compounds ; }, abstract = {Plant-to-plant volatile-mediated communication and subsequent induced resistance to insect herbivores is common. Less clear is the adaptive significance of these interactions; what selective mechanisms favour plant communication and what conditions allow individuals to benefit by both emitting and responding to cues? We explored the predictions of two non-exclusive hypotheses to explain why plants might emit cues, the kin selection hypothesis (KSH) and the mutual benefit hypothesis (MBH). We examined 15 populations of sagebrush that experience a range of naturally occurring herbivory along a 300 km latitudinal transect. As predicted by the KSH, we found several uncommon chemotypes with some chemotypes occurring only within a single population. Consistent with the MBH, chemotypic diversity was negatively correlated with herbivore pressure; sites with higher levels of herbivory were associated with a few common cues broadly recognized by most individuals. These cues varied among different populations. Our results are similar to those reported for anti-predator signalling in vertebrates.}, } @article {pmid34669158, year = {2021}, author = {Fisktjønmo, GLH and Næss, MW and Bårdsen, BJ}, title = {The Relative Importance of "Cooperative Context" and Kinship in Structuring Cooperative Behavior : A Comparative Study of Saami Reindeer Herders.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {32}, number = {4}, pages = {677-705}, pmid = {34669158}, issn = {1936-4776}, support = {240280//Norges Forskningsråd/ ; 76915//Nordic Centre of Excellence/ ; 362257//The Terrestrial flagship, Fram Centre/ ; 369902//The Terrestrial flagship, Fram Centre/ ; }, mesh = {Animals ; *Cooperative Behavior ; Farmers ; Humans ; *Reindeer ; }, abstract = {Kin relations have a strong theoretical and empirical basis for explaining cooperative behavior. Nevertheless, there is growing recognition that context-the cooperative environment of an individual-also shapes the willingness of individuals to cooperate. For nomadic pastoralists in Norway, cooperation among both kin and non-kin is an essential predictor for success. The northern parts of the country are characterized by a history of herder-herder competition exacerbating between-herder conflict, lack of trust, and subsequent coordination problems. In contrast, because of a history of herder-farmer competition, southern Norway is characterized by high levels of between-herder coordination and trust. This comparative study investigates the relative importance of "cooperative context" and kinship in structuring cooperative behavior using an experimental gift game. The main findings from this study were that in the South, a high level of cooperation around an individual pushes gifts to be distributed evenly among other herders. Nevertheless, kinship matters, since close kin give and receive larger gifts. In contrast, kinship seems to be the main factor affecting gift distribution in the North. Herders in the North are also concerned with distributing gifts equally, albeit limiting them to close kin: the level of intragroup cooperation drives gifts to be distributed evenly among other closely related herders. The observed regional contrasts in cooperative decisions fit with the different historical levels of conflict and trust in the two regions: whereas herders in the South are affected by both cooperative context and kinship, kinship seems to be the main determinant of cooperation in the North.}, } @article {pmid34657470, year = {2021}, author = {Zwolak, R and Clement, D and Sih, A and Schreiber, SJ}, title = {Mast seeding promotes evolution of scatter-hoarding.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {376}, number = {1839}, pages = {20200375}, pmid = {34657470}, issn = {1471-2970}, mesh = {Animals ; *Fagus ; Feeding Behavior ; *Hoarding ; Mice ; Reproduction ; Seeds ; }, abstract = {Many plant species worldwide are dispersed by scatter-hoarding granivores: animals that hide seeds in numerous, small caches for future consumption. Yet, the evolution of scatter-hoarding is difficult to explain because undefended caches are at high risk of pilferage. Previous models have attempted to solve this problem by giving cache owners large advantages in cache recovery, by kin selection, or by introducing reciprocal pilferage of 'shared' seed resources. However, the role of environmental variability has been so far overlooked in this context. One important form of such variability is masting, which is displayed by many plant species dispersed by scatterhoarders. We use a mathematical model to investigate the influence of masting on the evolution of scatter-hoarding. The model accounts for periodically varying annual seed fall, caching and pilfering behaviour, and the demography of scatterhoarders. The parameter values are based mostly on research on European beech (Fagus sylvatica) and yellow-necked mice (Apodemus flavicollis). Starvation of scatterhoarders between mast years decreases the population density that enters masting events, which leads to reduced seed pilferage. Satiation of scatterhoarders during mast events lowers the reproductive cost of caching (i.e. the cost of caching for the future rather than using seeds for current reproduction). These reductions promote the evolution of scatter-hoarding behaviour especially when interannual variation in seed fall and the period between masting events are large. This article is part of the theme issue 'The ecology and evolution of synchronized seed production in plants'.}, } @article {pmid34627803, year = {2021}, author = {Lessard, S and Li, C and Zheng, XD and Tao, Y}, title = {Inclusive fitness and Hamilton's rule in a stochastic environment.}, journal = {Theoretical population biology}, volume = {142}, number = {}, pages = {91-99}, doi = {10.1016/j.tpb.2021.09.007}, pmid = {34627803}, issn = {1096-0325}, mesh = {*Biological Evolution ; Cooperative Behavior ; Game Theory ; Haploidy ; *Prisoner Dilemma ; Probability ; }, abstract = {The evolution of cooperation in Prisoner's Dilemmas with additive random cost and benefit for cooperation cannot be accounted for by Hamilton's rule based on mean effects transferred from recipients to donors weighted by coefficients of relatedness, which defines inclusive fitness in a constant environment. Extensions that involve higher moments of stochastic effects are possible, however, and these are connected to a concept of random inclusive fitness that is frequency-dependent. This is shown in the setting of pairwise interactions in a haploid population with the same coefficient of relatedness between interacting players. In an infinite population, fixation of cooperation is stochastically stable if a mean geometric inclusive fitness of defection when rare is negative, while fixation of defection is stochastically unstable if a mean geometric inclusive fitness of cooperation when rare is positive, and these conditions are generally not equivalent. In a finite population, the probability for cooperation to ultimately fix when represented once exceeds the probability under neutrality or the corresponding probability for defection if the mean inclusive fitness of cooperation when its frequency is 1/3 or 1/2, respectively, exceeds 1. All these results rely on the simplifying assumption of a linear fitness function. It is argued that meaningful applications of random inclusive fitness in complex settings (multi-player game, diploidy, population structure) would generally require conditions of weak selection and additive gene action.}, } @article {pmid34616345, year = {2021}, author = {Tanskanen, AO and Danielsbacka, M and Hämäläinen, H and Solé-Auró, A}, title = {Does Transition to Retirement Promote Grandchild Care? Evidence From Europe.}, journal = {Frontiers in psychology}, volume = {12}, number = {}, pages = {738117}, pmid = {34616345}, issn = {1664-1078}, abstract = {Evolutionary theory posits that grandparents can increase their inclusive fitness by investing in their grandchildren. This study explored whether the transition to retirement affected the amount of grandchild care that European grandparents provided to their descendants. Data from five waves of the longitudinal Survey of Health, Aging, and Retirement in Europe collected between 2004 and 2015 from 15 countries were used. We executed within-person (or fixed-effect) regression models, which considered individual variations and person-specific changes over time. It was detected that transition to retirement was associated with increased grandchild care among both grandmothers and grandfathers. However, the effect of retirement was stronger for grandfathers than for grandmothers. Moreover, transition to retirement was associated with increased grandchild care among both maternal and paternal grandparents, but there was no significant difference between lineages in the magnitude of the effect of transition to retirement on grandchild care. In public debate retirees are often considered a burden to society but the present study indicated that when grandparents retire, their investment in grandchildren increased. The findings are discussed with reference to key evolutionary theories that consider older adults' tendency to invest time and resources in their grandchildren.}, } @article {pmid34592345, year = {2021}, author = {Leonardo, DE and Nogueira-Filho, SLG and de Góes Maciel, F and Biondo, C and Mendl, M and Nogueira, SSDC}, title = {Third-party conflict interventions are kin biased in captive white-lipped peccaries (Mammalia, Tayassuidae).}, journal = {Behavioural processes}, volume = {193}, number = {}, pages = {104524}, doi = {10.1016/j.beproc.2021.104524}, pmid = {34592345}, issn = {1872-8308}, mesh = {Aggression ; Animals ; *Artiodactyla ; Humans ; Male ; Mammals ; Social Behavior ; }, abstract = {Third-party interventions may regulate conflicts to reduce aggression and promote cohesion amongst group members, but are rarely documented in ungulates. The white-lipped peccary (Tayassu pecari) lives in mixed-sex herds of hundreds of individuals in Neotropical forests, which are likely to benefit from mechanisms that sustain social cohesiveness. We examined third-party conflict interventions between individuals in captive groups of white-lipped peccaries. During a period of 60 days, we recorded agonistic interactions and occurrences of third-party conflict interventions, and estimated the genetic relatedness between the individuals involved using multilocus microsatellite genotypes. Most third-party conflict interventions were by the dominant male of each group, resulting in conflict termination 100% of the time. Our results also revealed that white-lipped peccaries favour their closest relatives and that individuals showed lower levels of aggression towards kin than to non-kin, and interventions on behalf of kin were more frequent than on behalf of non-kin. Our findings support the idea that genetic relatedness is fundamental in both social structure and third-party conflict interventions in this species, allowing us to suggest that kin selection could have a key role in the evolution of social behaviour of white-lipped peccaries.}, } @article {pmid34555177, year = {2021}, author = {Josi, D and Heg, D and Takeyama, T and Bonfils, D and Konovalov, DA and Frommen, JG and Kohda, M and Taborsky, M}, title = {Age- and sex-dependent variation in relatedness corresponds to reproductive skew, territory inheritance, and workload in cooperatively breeding cichlids.}, journal = {Evolution; international journal of organic evolution}, volume = {75}, number = {11}, pages = {2881-2897}, pmid = {34555177}, issn = {1558-5646}, mesh = {Animals ; Breeding ; *Cichlids/genetics ; Humans ; Social Structure ; Workload ; }, abstract = {Kin selection plays a major role in the evolution of cooperative systems. However, many social species exhibit complex within-group relatedness structures, where kin selection alone cannot explain the occurrence of cooperative behavior. Understanding such social structures is crucial to elucidate the evolution and maintenance of multi-layered cooperative societies. In lamprologine cichlids, intragroup relatedness seems to correlate positively with reproductive skew, suggesting that in this clade dominants tend to provide reproductive concessions to unrelated subordinates to secure their participation in brood care. We investigate how patterns of within-group relatedness covary with direct and indirect fitness benefits of cooperation in a highly social vertebrate, the cooperatively breeding, polygynous lamprologine cichlid Neolamprologus savoryi. Behavioral and genetic data from 43 groups containing 578 individuals show that groups are socially and genetically structured into subgroups. About 17% of group members were unrelated immigrants, and average relatedness between breeders and brood care helpers declined with helper age due to group membership dynamics. Hence the relative importance of direct and indirect fitness benefits of cooperation depends on helper age. Our findings highlight how both direct and indirect fitness benefits of cooperation and group membership can select for cooperative behavior in societies comprising complex social and relatedness structures.}, } @article {pmid34530032, year = {2021}, author = {Priklopil, T and Lehmann, L}, title = {Metacommunities, fitness and gradual evolution.}, journal = {Theoretical population biology}, volume = {142}, number = {}, pages = {12-35}, doi = {10.1016/j.tpb.2021.09.002}, pmid = {34530032}, issn = {1096-0325}, mesh = {*Biological Evolution ; *Models, Genetic ; Phenotype ; Population Dynamics ; Selection, Genetic ; }, abstract = {We analyze the evolution of a multidimensional quantitative trait in a class-structured focal species interacting with other species in a wider metacommunity. The evolutionary dynamics in the focal species as well as the ecological dynamics of the whole metacommunity is described as a continuous-time process with birth, physiological development, dispersal, and death given as rates that can depend on the state of the whole metacommunity. This can accommodate complex local community and global metacommunity environmental feedbacks owing to inter- and intra-specific interactions, as well as local environmental stochastic fluctuations. For the focal species, we derive a fitness measure for a mutant allele affecting class-specific trait expression. Using classical results from geometric singular perturbation theory, we provide a detailed proof that if the effect of the mutation on phenotypic expression is small ("weak selection"), the large system of dynamical equations needed to describe selection on the mutant allele in the metacommunity can be reduced to a single ordinary differential equation on the arithmetic mean mutant allele frequency that is of constant sign. This invariance on allele frequency entails the mutant either dies out or will out-compete the ancestral resident (or wild) type. Moreover, the directional selection coefficient driving arithmetic mean allele frequency can be expressed as an inclusive fitness effect calculated from the resident metacommunity alone, and depends, as expected, on individual fitness differentials, relatedness, and reproductive values. This formalizes the Darwinian process of gradual evolution driven by random mutation and natural selection in spatially and physiologically class-structured metacommunities.}, } @article {pmid34424594, year = {2021}, author = {Premate, E and Borko, Š and Kralj-Fišer, S and Jennions, M and Fišer, Ž and Balázs, G and Bíró, A and Bračko, G and Copilaş-Ciocianu, D and Hrga, N and Herczeg, G and Rexhepi, B and Zagmajster, M and Zakšek, V and Fromhage, L and Fišer, C}, title = {No room for males in caves: Female-biased sex ratio in subterranean amphipods of the genus Niphargus.}, journal = {Journal of evolutionary biology}, volume = {34}, number = {10}, pages = {1653-1661}, doi = {10.1111/jeb.13917}, pmid = {34424594}, issn = {1420-9101}, mesh = {*Amphipoda/genetics ; Animals ; Caves ; Ecosystem ; Female ; Male ; Phylogeny ; Sex Ratio ; }, abstract = {Sex allocation theory predicts that the proportion of daughters to sons will evolve in response to ecological conditions that determine the costs and benefits of producing each sex. All else being equal, the adult sex ratio (ASR) should also vary with ecological conditions. Many studies of subterranean species reported female-biased ASR, but no systematic study has yet been conducted. We test the hypothesis that the ASR becomes more female-biased with increased isolation from the surface. We compiled a data set of ASRs of 35 species in the subterranean amphipod Niphargus, each living in one of three distinct habitats (surface-subterranean boundary, cave streams, phreatic lakes) representing an environmental gradient of increased isolation underground. The ASR was female-biased in 27 of 35 species; the bias was statistically significant in 12 species. We found a significant difference in the ASR among habitats after correction for phylogeny. It is most weakly female-biased at the surface-subterranean boundary and most strongly female-biased in phreatic lakes. Additional modelling suggests that the ASR has evolved towards a single value for both surface-subterranean boundary and cave stream-dwelling species, and another value for 9 of 11 phreatic lake dwellers. We suggest that a history of inbreeding in subterranean populations might lower inbreeding depression such that kin selection favours mating with siblings. This could select for a female-biased offspring sex ratio due to local mate competition among brothers. The observed patterns in sex ratios in subterranean species make them a group worthy of more attention from those interested in sex allocation theory.}, } @article {pmid34403632, year = {2021}, author = {Croft, DP and Weiss, MN and Nielsen, MLK and Grimes, C and Cant, MA and Ellis, S and Franks, DW and Johnstone, RA}, title = {Kinship dynamics: patterns and consequences of changes in local relatedness.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1957}, pages = {20211129}, pmid = {34403632}, issn = {1471-2954}, mesh = {Female ; Humans ; *Menopause ; *Social Behavior ; Social Evolution ; }, abstract = {Mounting evidence suggests that patterns of local relatedness can change over time in predictable ways, a process termed kinship dynamics. Kinship dynamics may occur at the level of the population or social group, where the mean relatedness across all members of the population or group changes over time, or at the level of the individual, where an individual's relatedness to its local group changes with age. Kinship dynamics are likely to have fundamental consequences for the evolution of social behaviour and life history because they alter the inclusive fitness payoffs to actions taken at different points in time. For instance, growing evidence suggests that individual kinship dynamics have shaped the evolution of menopause and age-specific patterns of helping and harming. To date, however, the consequences of kinship dynamics for social evolution have not been widely explored. Here we review the patterns of kinship dynamics that can occur in natural populations and highlight how taking a kinship dynamics approach has yielded new insights into behaviour and life-history evolution. We discuss areas where analysing kinship dynamics could provide new insight into social evolution, and we outline some of the challenges in predicting and quantifying kinship dynamics in natural populations.}, } @article {pmid34391806, year = {2021}, author = {He, QQ and Zheng, XD and Mace, R and Tao, Y and Ji, T}, title = {Hamilton's rule and kin competition in a finite kin population.}, journal = {Journal of theoretical biology}, volume = {529}, number = {}, pages = {110862}, doi = {10.1016/j.jtbi.2021.110862}, pmid = {34391806}, issn = {1095-8541}, mesh = {*Altruism ; *Biological Evolution ; Humans ; }, abstract = {Kin selection means that individuals can increase their own inclusive fitness through displaying more altruistically toward their relatives. So, Hamilton's rule says kin selection will work if the coefficient of relatedness exceeds the cost-to-benefit ratio of the altruistic act. However, some studies have shown that the kin competition due to the altruism among relatives can reduce, and even totally negate, the kin-selected benefits of altruism toward relatives. In order to understand how the evolution of cooperation is influenced by both kin selection and kin competition under a general theoretical framework, we here consider the evolutionary dynamics of cooperation in a finite kin population, where kin competition is incorporated into a simple Prisoner's Dilemma game between relatives. Differently from the previous studies, we emphasize that the difference between the effects of mutually and unilaterally altruistic acts on kin competition may play an important role for the evolution of cooperation. The main results not only show the conditions that Hamilton's rule still works under the kin competition but also reveal the evolutionary biological mechanism driving the evolution of cooperation in a finite kin population.}, } @article {pmid34367662, year = {2021}, author = {Iritani, R and West, SA and Abe, J}, title = {Cooperative interactions among females can lead to even more extraordinary sex ratios.}, journal = {Evolution letters}, volume = {5}, number = {4}, pages = {370-384}, pmid = {34367662}, issn = {2056-3744}, abstract = {Hamilton's local mate competition theory provided an explanation for extraordinary female-biased sex ratios in a range of organisms. When mating takes place locally, in structured populations, a female-biased sex ratio is favored to reduce competition between related males, and to provide more mates for males. However, there are a number of wasp species in which the sex ratios appear to more female biased than predicted by Hamilton's theory. It has been hypothesized that the additional female bias in these wasp species results from cooperative interactions between females. We investigated theoretically the extent to which cooperation between related females can interact with local mate competition to favor even more female-biased sex ratios. We found that (i) cooperation between females can lead to sex ratios that are more female biased than predicted by local competition theory alone, and (ii) sex ratios can be more female biased when the cooperation occurs from offspring to mothers before dispersal, rather than cooperation between siblings after dispersal. Our models formally confirm the verbal predictions made in previous experimental studies, which could be applied to a range of organisms. Specifically, cooperation can help explain sex ratio biases in Sclerodermus and Melittobia wasps, although quantitative comparisons between predictions and data suggest that some additional factors may be operating.}, } @article {pmid34366975, year = {2021}, author = {Novakova, J and Machová, K and Sýkorová, K and Zíka, V and Flegr, J}, title = {Looking Like a Million Dollars: Does Attractiveness Priming Increase Altruistic Behavior in Experimental Games?.}, journal = {Frontiers in psychology}, volume = {12}, number = {}, pages = {658466}, pmid = {34366975}, issn = {1664-1078}, abstract = {The emergence of altruistic behavior constitutes one of the most widely studied problems in evolutionary biology and behavioral science. Multiple explanations have been proposed, most importantly including kin selection, reciprocity, and costly signaling in sexual selection. In order to test the latter, this study investigated whether people behave more altruistically when primed by photographs of attractive faces and whether more or less altruistic people differ in the number of sexual and romantic partners. Participants in the general population (N = 158, 84 F, 74 M) first rated the attractiveness of photographs of 20 faces of the opposite (sexually preferred) sex and then played the Dictator and Ultimatum Games (DG and UG). The photograph rating acted as priming; half the participants received photographs of people rated as more attractive than average in an earlier study, and the other half received photographs previously rated as less attractive. The attractiveness-primed participants, especially men, were expected to behave more altruistically-signaling that they are desirable, resource-possessing partners. We also expected altruists to self-report more sexual and romantic partners. The observed difference between altruistic behaviors in the attractiveness- and unattractiveness-primed groups occurred in UG offers, however, in the opposite than expected direction in women. The number of sexual partners was positively correlated to minimum acceptable offers (MAOs) in the UG, in line with expectations based on the theory of costly signaling.}, } @article {pmid34344179, year = {2021}, author = {Lymbery, SJ and Tomkins, JL and Buzatto, BA and Hosken, DJ}, title = {Kin-mediated plasticity in alternative reproductive tactics.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1956}, pages = {20211069}, pmid = {34344179}, issn = {1471-2954}, mesh = {*Acaridae ; Animals ; Humans ; Male ; *Mites ; Phenotype ; Population Density ; Reproduction ; Sexual Behavior, Animal ; }, abstract = {Conditional strategies occur when the relative fitness pay-off from expressing a given phenotype is contingent upon environmental circumstances. This conditional strategy model underlies cases of alternative reproductive tactics, in which individuals of one sex employ different means to obtain reproduction. How kin structure affects the expression of alternative reproductive tactics remains unexplored. We address this using the mite Rhizoglyphus echinopus, in which large males develop into aggressive 'fighters' and small males develop into non-aggressive 'scramblers.' Because only fighters kill their rivals, they should incur a greater indirect fitness cost when competing with their relatives, and thus fighter expression could be reduced in the presence of relatives. We raised mites in full-sibling or mixed-sibship groups and found that fighters were more common at higher body weights in full-sibling groups, not less common as we predicted (small individuals were almost exclusively scramblers in both treatments). This result could be explained if relatedness and cue variability are interpreted signals of population density, since fighters are more common at low densities in this species. Alternatively, our results may indicate that males compete more intensely with relatives in this species. We provide the first evidence of kin-mediated plasticity in the expression of alternative reproductive tactics.}, } @article {pmid34330328, year = {2021}, author = {Nikolajsen, H and Richardson, EV and Sandal, LF and Juul-Kristensen, B and Troelsen, J}, title = {Fitness for all: how do non-disabled people respond to inclusive fitness centres?.}, journal = {BMC sports science, medicine & rehabilitation}, volume = {13}, number = {1}, pages = {81}, pmid = {34330328}, issn = {2052-1847}, abstract = {BACKGROUND: Representation of people with disabilities in fitness centres is lacking, despite initiatives to promote inclusion mainly in the UK and USA. Success creating these inclusive spaces is mixed and few were crafted taking into account attitudes and biases of non-disabled co-members. Inclusive fitness centres have not gained much attention in Denmark, and the campaign 'Fitness for All - fitness for people with physical disabilities' was initiated. The aim of this study was shaped by two key questions; 1) what is the ideal fitness space from the perception of non-disabled fitness users? and 2) how might their dis/ableist attitudes negate inclusion in three future pilot inclusive fitness centres across Denmark?

METHOD: Three focus groups involving 5-7 (total n = 18) adult non-disabled participants were conducted. Aged ranged between 19 and 75 years, both men and women were involved, with fitness centre experiences ranging from 0 to 20+ years. Interviews were transcribed and analysed using Malterud's four-step method of systematic text condensation.

RESULTS: Of most importance was a pleasant atmosphere which should make them feel welcome and comfortable. Good social relations within the space were also highly valued. Participants welcomed people with physical disabilities but predicted many challenges with an inclusive fitness centre and expressed unconscious ableist attitudes.

CONCLUSION: The current study adds essential knowledge regarding how non-disabled people perceive the ideal inclusive fitness centre. A welcoming and inviting atmosphere is essential whereas social skills, ableism, ignorance, and preconceptions are important barriers that may hinder inclusion of participants with disabilities in inclusive fitness centres.}, } @article {pmid34309511, year = {2021}, author = {Bensch, HM and O'Connor, EA and Cornwallis, CK}, title = {Living with relatives offsets the harm caused by pathogens in natural populations.}, journal = {eLife}, volume = {10}, number = {}, pages = {}, pmid = {34309511}, issn = {2050-084X}, mesh = {Animals ; *Behavior, Animal ; Ecology ; *Genetic Variation ; Microsatellite Repeats ; Phylogeny ; Reproduction ; *Social Behavior ; Survival ; }, abstract = {Living with relatives can be highly beneficial, enhancing reproduction and survival. High relatedness can, however, increase susceptibility to pathogens. Here, we examine whether the benefits of living with relatives offset the harm caused by pathogens, and if this depends on whether species typically live with kin. Using comparative meta-analysis of plants, animals, and a bacterium (nspecies = 56), we show that high within-group relatedness increases mortality when pathogens are present. In contrast, mortality decreased with relatedness when pathogens were rare, particularly in species that live with kin. Furthermore, across groups variation in mortality was lower when relatedness was high, but abundances of pathogens were more variable. The effects of within-group relatedness were only evident when pathogens were experimentally manipulated, suggesting that the harm caused by pathogens is masked by the benefits of living with relatives in nature. These results highlight the importance of kin selection for understanding disease spread in natural populations.}, } @article {pmid34305981, year = {2021}, author = {Subrahmaniam, HJ and Roby, D and Roux, F}, title = {Toward Unifying Evolutionary Ecology and Genomics to Understand Positive Plant-Plant Interactions Within Wild Species.}, journal = {Frontiers in plant science}, volume = {12}, number = {}, pages = {683373}, pmid = {34305981}, issn = {1664-462X}, abstract = {In a local environment, plant networks include interactions among individuals of different species and among genotypes of the same species. While interspecific interactions are recognized as main drivers of plant community patterns, intraspecific interactions have recently gained attention in explaining plant community dynamics. However, an overview of intraspecific genotype-by-genotype interaction patterns within wild plant species is still missing. From the literature, we identified 91 experiments that were mainly designed to investigate the presence of positive interactions based on two contrasting hypotheses. Kin selection theory predicts partisan help given to a genealogical relative. The rationale behind this hypothesis relies on kin/non-kin recognition, with the positive outcome of kin cooperation substantiating it. On the other hand, the elbow-room hypothesis supports intraspecific niche partitioning leading to positive outcome when genetically distant genotypes interact. Positive diversity-productivity relationship rationalizes this hypothesis, notably with the outcome of overyielding. We found that both these hypotheses have been highly supported in experimental studies despite their opposite predictions between the extent of genetic relatedness among neighbors and the level of positive interactions. Interestingly, we identified a highly significant effect of breeding system, with a high proportion of selfing species associated with the presence of kin cooperation. Nonetheless, we identified several shortcomings regardless of the species considered, such as the lack of a reliable estimate of genetic relatedness among genotypes and ecological characterization of the natural habitats from which genotypes were collected, thereby impeding the identification of selective drivers of positive interactions. We therefore propose a framework combining evolutionary ecology and genomics to establish the eco-genomic landscape of positive GxG interactions in wild plant species.}, } @article {pmid34302740, year = {2021}, author = {Teunissen, N and Kingma, SA and Fan, M and Roast, MJ and Peters, A}, title = {Context-dependent social benefits drive cooperative predator defense in a bird.}, journal = {Current biology : CB}, volume = {31}, number = {18}, pages = {4120-4126.e4}, doi = {10.1016/j.cub.2021.06.070}, pmid = {34302740}, issn = {1879-0445}, mesh = {Animals ; Biological Evolution ; Cooperative Behavior ; Humans ; *Passeriformes/physiology ; Reproduction/physiology ; Social Behavior ; *Songbirds/physiology ; }, abstract = {Understanding the major evolutionary transition from solitary individuals to complex societies is hampered by incomplete insight into the drivers of living in cooperative groups.[1-3] This may be because the benefits of sociality can derive from group living itself (e.g., dilution of predation risk),[4][,][5] or depend on social context (e.g., kin or potential mates represent beneficial group members).[6-8] Cooperative breeders, where non-breeding subordinates assist breeders, have provided important insights into the drivers of cooperation, but comprehensive assessment of diverse potential benefits has been hindered by a prevailing focus on benefits deriving from raising offspring.[9-11] We propose a novel paradigm to tease apart different benefits by comparing cooperative responses to predators threatening dependent young and adult group members according to their value for the responding individual. Applying this approach in purple-crowned fairy-wrens, Malurus coronatus, we show that non-breeding subordinates are more responsive to nest predators-a threat to offspring-when their probability of inheriting a breeding position is greater-irrespective of group size, relatedness to offspring, or opportunity to showcase individual quality to potential mates. This suggests that offspring defense is modulated according to the benefits of raising future helpers. Conversely, when predators pose a threat to adults, responsiveness depends on social context: subordinates respond more often when kin or potential mates are under threat, or when group members are associated with mutualistic social bonds, indirect genetic benefits, and future reproductive benefits.[9][,][12][,][13] Our results demonstrate that direct and kin-selected benefits of sociality are context dependent, and highlight the importance of predation risk in driving complex sociality.}, } @article {pmid34290628, year = {2021}, author = {Hollon, SD and Andrews, PW and Thomson, JA}, title = {Cognitive Behavior Therapy for Depression From an Evolutionary Perspective.}, journal = {Frontiers in psychiatry}, volume = {12}, number = {}, pages = {667592}, pmid = {34290628}, issn = {1664-0640}, abstract = {Evolutionary medicine attempts to solve a problem with which traditional medicine has struggled historically; how do we distinguish between diseased states and "healthy" responses to disease states? Fever and diarrhea represent classic examples of evolved adaptations that increase the likelihood of survival in response to the presence of pathogens in the body. Whereas, the severe mental disorders like psychotic mania or the schizophrenias may involve true "disease" states best treated pharmacologically, most non-psychotic "disorders" that revolve around negative affects like depression or anxiety are likely adaptations that evolved to serve a function that increased inclusive fitness in our ancestral past. What this likely means is that the proximal mechanisms underlying the non-psychotic "disorders" are "species typical" and neither diseases nor disorders. Rather, they are coordinated "whole body" responses that prepare the individual to respond in a maximally functional fashion to the variety of different challenges that our ancestors faced. A case can be made that depression evolved to facilitate a deliberate cognitive style (rumination) in response to complex (often social) problems. What this further suggests is that those interventions that best facilitate the functions that those adaptations evolved to serve (such as rumination) are likely to be preferred over those like medications that simply anesthetize the distress. We consider the mechanisms that evolved to generate depression and the processes utilized in cognitive behavior therapy to facilitate those functions from an adaptationist evolutionary perspective.}, } @article {pmid34270793, year = {2021}, author = {Barra, T and Viblanc, VA and Saraux, C and Murie, JO and Dobson, FS}, title = {Parental investment in the Columbian ground squirrel: empirical tests of sex allocation models.}, journal = {Ecology}, volume = {102}, number = {11}, pages = {e03479}, doi = {10.1002/ecy.3479}, pmid = {34270793}, issn = {1939-9170}, mesh = {Animals ; Biological Evolution ; Female ; Male ; *Reproduction ; Sciuridae ; Selection, Genetic ; *Sex Ratio ; }, abstract = {Parental allocation of resources into male or female offspring and differences in the balance of offspring sexes in natural populations are central research topics in evolutionary ecology. Fisher (Fisher, R. A. 1930. The genetical theory of natural selection, Clarendon Press, Oxford, UK) identified frequency-dependent selection as the mechanism responsible for an equal investment in the sexes of offspring at the end of parental care. Three main theories have been proposed for explaining departures from Fisherian sex ratios in light of variation in environmental (social) and individual (maternal condition) characteristics. The Trivers-Willard model (Trivers, R., and D. Willard. 1973. Natural selection of parental ability to vary the sex ratio of offspring. Science 179:90-92) of male-biased sex allocation by mothers in the best body condition is based on the competitive ability of male offspring for future access to mates and thus superior reproduction. The local resource competition model is based on competitive interactions in matrilines, as occur in many mammal species, where producing sons reduces future intrasexual competition with daughters. A final model invokes advantages of maintaining matrilines for philopatric females, despite any increased competition among females. We used 29 yr of pedigree and demographic data to evaluate these hypotheses in the Colombian ground squirrel (Urocitellus columbianus), a semisocial species characterized by strong female philopatry. Overall, male offspring were heavier than female offspring at birth and at weaning, suggesting a higher production cost. With more local kin present, mothers in the best condition biased their offspring sex ratio in favor of males, and mothers in poor condition biased offspring sex ratio in favor of females. Without co-breeding close kin, the pattern was reversed, with mothers in the best condition producing more daughters, and mothers in poor condition producing more sons. Our results do not provide strong support for any of the single-factor models of allocation to the sexes of offspring, but rather suggest combined influences of relative maternal condition and matriline dominance on offspring sex ratio.}, } @article {pmid34238997, year = {2021}, author = {Arnot, M and Mace, R}, title = {An evolutionary perspective on kin care directed up the generations.}, journal = {Scientific reports}, volume = {11}, number = {1}, pages = {14163}, pmid = {34238997}, issn = {2045-2322}, mesh = {Adolescent ; Adult ; *Biological Evolution ; *Caregivers ; Child ; *Family ; Female ; Fertility ; Humans ; Middle Aged ; Models, Biological ; Parents ; Young Adult ; }, abstract = {Within evolutionary sciences, care towards younger kin is well understood from an inclusive fitness framework, but why adults would care for older relatives has been less well researched. One existing model has argued that care directed towards elderly parents might be adaptive because of their benefits as carers themselves, with their help freeing up the middle generations' energy which can then be invested into direct reproduction. However, in this model, elder care is more beneficial to fitness if the carer is fecund. To offer an initial test of this hypothesis, we look at caring behaviour relative to fecundity status in a contemporary dataset from the United Kingdom. If elder care is contingent on possible direct fitness benefits, we would expect women who are still menstruating to care more for their parents than women who can no longer reproduce. Based on this, we also predict that women who are physiologically post-reproductive would invest more in their grandchildren, through whom they can increase their inclusive fitness. After controlling for age and other relevant factors, we find that women who are still menstruating spend more time caring for their parents than those who are not, and the reverse is true when looking at time spent caring for grandchildren. These findings demonstrate that potential inclusive fitness outcomes influence how women allocate care up and down the generations.}, } @article {pmid34201317, year = {2021}, author = {Ando, J and Kawamoto, T}, title = {Genetic and Environmental Structure of Altruism Characterized by Recipients in Relation to Personality.}, journal = {Medicina (Kaunas, Lithuania)}, volume = {57}, number = {6}, pages = {}, pmid = {34201317}, issn = {1648-9144}, support = {FY2013-FY2015//TopicSetting Program to Advanced Cutting-Edge Humanities and Social Sciences Research/ ; }, mesh = {Adult ; *Altruism ; Family ; Humans ; *Personality/genetics ; Self Report ; }, abstract = {Background and Objectives: Altruism is a form of prosocial behavior with the goal of increasing the fitness of another individual as a recipient while reducing the fitness of the actor. Although there are many studies on its heterogeneity, only a few behavioral genetic studies have been conducted to examine different recipient types: family members favored by kin selection, the dynamic network of friends and acquaintances as direct reciprocity, and strangers as indirect reciprocity. Materials and Methods: This study investigated the genetic and environmental structure of altruism with reference to recipient types measured by the self-report altruism scale distinguished by the recipient (the SRAS-DR) and examine the relationship to personality dimensions measured by the NEO-FFI with a sample of 461 adult Japanese twin pairs. Results: The present study shows that there is a single common factor of altruism: additive genetic effects explain 51% of altruism without a shared environmental contribution. The genetic contribution of this single common factor is explained by the genetic factors of neuroticism (N), extraversion (E), openness to experience (O), and conscientiousness (C), as well as a common genetic factor specific to altruism. Only altruism toward strangers is affected by shared environmental factors. Conclusions: Different types of altruistic personality are constructed by specific combinational profiles of general personality traits such as the Big Five as well as a genetic factor specific to altruism in each specific way.}, } @article {pmid34193863, year = {2021}, author = {He, Y and Xu, H and Liu, H and Luo, M and Chu, C and Fang, S}, title = {Sexual competition and kin recognition co-shape the traits of neighboring dioecious Diospyros morrisiana seedlings.}, journal = {Horticulture research}, volume = {8}, number = {1}, pages = {162}, pmid = {34193863}, issn = {2662-6810}, support = {31370441//National Science Foundation of China | National Natural Science Foundation of China-Yunnan Joint Fund (NSFC-Yunnan Joint Fund)/ ; 31670628//National Science Foundation of China | National Natural Science Foundation of China-Yunnan Joint Fund (NSFC-Yunnan Joint Fund)/ ; }, abstract = {Plants respond differently to the identity of their neighbors, such as their sex and kinship, showing plasticity in their traits. However, how the functional traits of dioecious trees are shaped by the recognition of neighbors with different sex and kinship remains unknown. In this study, we set up an experiment with different kin/nonkin and inter/intrasexual combinations for a dioecious tree species, Diospyros morrisiana. The results showed that plants grew better with nonkin and intrasexual neighbors than with kin and intersexual neighbors. Kin combinations had significantly shorter root length in the resource-overlapping zone than nonkin combinations, suggesting that kin tended to reduce competition by adjusting their root distribution, especially among female siblings. Our study suggested that the seedling growth of D. morrisiana was affected by both the relatedness and sexual identity of neighboring plants. Further analysis by gas chromatography-mass spectrometry showed that the root exudate composition of female seedlings differed from that of male seedlings. Root exudates may play important roles in sex competition in dioecious plants. This study indicates that sex-specific competition and kin recognition interact and co-shape the traits of D. morrisiana seedlings, while intrasexual and nonkin neighbors facilitate the growth of seedlings. Our study implies that kin- and sex-related interactions depend on different mechanisms, kin selection, and niche partitioning, respectively. These results are critical for understanding how species coexist and how traits are shaped in nature.}, } @article {pmid34150907, year = {2021}, author = {Daly, M and Perry, G}, title = {In-Law Relationships in Evolutionary Perspective: The Good, the Bad, and the Ugly.}, journal = {Frontiers in sociology}, volume = {6}, number = {}, pages = {683501}, pmid = {34150907}, issn = {2297-7775}, abstract = {In-laws (relatives by marriage) are true kin because the descendants that they have in common make them "vehicles" of one another's inclusive fitness. From this shared interest flows cooperation and mutual valuation: the good side of in-law relationships. But there is also a bad side. Recent theoretical models err when they equate the inclusive fitness value of corresponding pairs of genetic and affinal (marital) relatives-brother and brother-in-law, daughter and daughter-in-law-partly because a genetic relative's reproduction always replicates ego's genes whereas reproduction by an affine may not, and partly because of distinct avenues for nepotism. Close genetic relatives compete, often fiercely, over familial property, but the main issues in conflict among marital relatives are different and diverse: fidelity and paternity, divorce and autonomy, and inclinations to invest in distinct natal kindreds. These conflicts can get ugly, even lethal. We present the results of a pilot study conducted in Bangladesh which suggests that heightened mortality arising from mother-in-law/daughter-in-law conflict may be a two-way street, and we urge others to replicate and extend these analyses.}, } @article {pmid34067982, year = {2021}, author = {Kalbarczyk, M}, title = {Non-Financial Support Provided to Parents in Stepfamilies: Empirical Examination of Europeans 50.}, journal = {International journal of environmental research and public health}, volume = {18}, number = {10}, pages = {}, pmid = {34067982}, issn = {1660-4601}, mesh = {Child ; *Divorce ; Ethnicity ; Europe ; Humans ; *Marriage ; White People ; }, abstract = {The aging of the population, coupled with increasing divorce and remarriage rates, are changing the structure of potential non-financial support for older parents. The purpose of this study was to examine support provided to parents aged 50+ in stepfamilies and to determine if the difference existed between help provided by natural children and stepchildren. The primary objective was to investigate whether blood ties were a significant determinant of the support if the quality of the relationship between the parent and a natural child or a stepchild was taken into account. The secondary objective was to answer the question to what extent the reciprocal exchange motive of support was observed in stepfamilies. The probability of non-financial support from children and stepchildren was estimated based on the sixth wave of the SHARE (Survey on Health, Ageing, and Retirement in Europe) database for European countries. Children in stepfamilies provided less non-financial help to parents than those in intact families. Stepchildren were less likely to be in stepparents' social networks, and stepparents provided less help with childcare for grandchildren than they did to their biological children. Relationship closeness and looking after grandchildren increased the probability of non-financial support to older parents, regardless of whether the donor was a natural child or a stepchild.}, } @article {pmid37588530, year = {2021}, author = {Kerry, N and Blake, KR and Murray, DR and Brooks, RC}, title = {Male descendant kin promote conservative views on gender issues and conformity to traditional norms.}, journal = {Evolutionary human sciences}, volume = {3}, number = {}, pages = {e34}, pmid = {37588530}, issn = {2513-843X}, abstract = {Political and social attitudes have been shown to differ by sex in a way that tracks individual self-interest. We propose that these attitudes also change strategically to serve the best interests of either male or female kin. To test this hypothesis, we developed a measure of gendered fitness interests (GFI) - an index which reflects the sex, relatedness and residual reproductive value of close kin. We predicted that people with male-biased GFI (i.e. people with more male kin of a reproductive age) would have more conservative attitudes towards gender-related issues (e.g. gender roles, women's rights, abortion rights). An online study using an American sample (N = 560) found support for this hypothesis. Further analyses revealed that this relationship was driven not only by people's own sex and reproductive value but also by those of their descendant kin. Exploratory analyses also found a positive association between male-biased GFI and a measure of conformity, as well as a smaller association between male-biased GFI and having voted Republican in the last election. Both of these associations were statistically mediated by gender-related conservatism. These findings are consistent with the hypothesis that GFI influences sociopolitical attitudes.}, } @article {pmid34039054, year = {2021}, author = {Rezvani Nejad, S and Borjali, A and Khanjani, M and Kruger, DJ}, title = {Belief in an Afterlife Influences Altruistic Helping Intentions in Alignment With Adaptive Tendencies.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {19}, number = {2}, pages = {14747049211011745}, pmid = {34039054}, issn = {1474-7049}, mesh = {*Altruism ; Biological Evolution ; Humans ; *Intention ; Iran ; Reproduction ; Selection, Genetic ; }, abstract = {Evolutionary definitions of altruism are only concerned with reproductive consequences and not motives or other psychological mechanisms, making them ideal for generalization to all forms of organisms. Hamilton's inclusive fitness theory explains altruistic behavior toward genetic relatives and has generated extensive empirical support. Trivers' theory of reciprocal altruism helps explain patterns of helping among non-kin, and other research has demonstrated that human helping intentions follow fitness consequences from age-based reproductive value on altruism. The current study examines a novel psychological factor, belief in the afterlife, which may influence altruistic helping intentions. Belief in the afterlife was incorporated into a previous study design assessing the effects of a target's genetic relatedness and age-based reproductive value. The influences of inclusive fitness and target age were reproduced in a non-Western sample of participants (N = 300) in Iran. Belief in the afterlife predicted the overall confidence of risking one's life to save another across all targets, and also moderated the effects of genetic relatedness and target age. Rather than promoting altruism equitably or advantaging those favored by adaptive tendencies, higher belief in an afterlife aligned with these tendencies in promoting further favoritism toward close kin and younger targets with higher reproductive value.}, } @article {pmid34007461, year = {2021}, author = {Caicoya, AL and Colell, M and Ensenyat, C and Amici, F}, title = {Problem solving in European bison (Bison bonasus): two experimental approaches.}, journal = {Royal Society open science}, volume = {8}, number = {4}, pages = {201901}, pmid = {34007461}, issn = {2054-5703}, abstract = {The ability to solve novel problems is crucial for individual fitness. However, studies on problem solving are usually done on few taxa, with species with low encephalization quotient being rarely tested. Here, we aimed to study problem solving in a non-domesticated ungulate species, European bison, with two experimental tasks. In the first task, five individuals were presented with a hanging barrel filled with food, which could either be directly accessed (control condition) or which could only be reached by pushing a tree stump in the enclosure below it and stepping on it (experimental condition). In the second task, five individuals were repeatedly fed by an experimenter using a novel bucket to retrieve food from a bag. Then, three identical buckets were placed in the enclosure, while the experimenter waited outside with the bag without feeding the bison, either with a bucket (control condition) or without it (experimental condition). In the first task, no bison moved the stump behind the barrel and/or stepped on it to reach the food. In the second task, two individuals solved the task by pushing the bucket within the experimenter's reach, twice in the experimental and twice in the control condition. We suggest that bison showed a limited ability to solve novel problems, and discuss the implications for their understanding of the functional aspects of the tasks.}, } @article {pmid34004128, year = {2021}, author = {Smith, J and Inglis, RF}, title = {Evaluating kin and group selection as tools for quantitative analysis of microbial data.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1951}, pages = {20201657}, pmid = {34004128}, issn = {1471-2954}, mesh = {*Biological Evolution ; *Selection, Genetic ; Social Behavior ; Social Evolution ; }, abstract = {Kin selection and multilevel selection theory are often used to interpret experiments about the evolution of cooperation and social behaviour among microbes. But while these experiments provide rich, detailed fitness data, theory is mostly used as a conceptual heuristic. Here, we evaluate how kin and multilevel selection theory perform as quantitative analysis tools. We reanalyse published microbial datasets and show that the canonical fitness models of both theories are almost always poor fits because they use statistical regressions misspecified for the strong selection and non-additive effects we show are widespread in microbial systems. We identify analytical practices in empirical research that suggest how theory might be improved, and show that analysing both individual and group fitness outcomes helps clarify the biology of selection. A data-driven approach to theory thus shows how kin and multilevel selection both have untapped potential as tools for quantitative understanding of social evolution in all branches of life.}, } @article {pmid33972440, year = {2021}, author = {Abe, J and Iritani, R and Tsuchida, K and Kamimura, Y and West, SA}, title = {A solution to a sex ratio puzzle in Melittobia wasps.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {118}, number = {20}, pages = {}, pmid = {33972440}, issn = {1091-6490}, mesh = {Animal Distribution/*physiology ; Animals ; Clutch Size/*genetics ; Competitive Behavior/physiology ; Cooperative Behavior ; Female ; Male ; Oviposition/*genetics ; *Sex Ratio ; Wasps/*genetics ; Zygote/growth & development ; }, abstract = {The puzzling sex ratio behavior of Melittobia wasps has long posed one of the greatest questions in the field of sex allocation. Laboratory experiments have found that, in contrast to the predictions of theory and the behavior of numerous other organisms, Melittobia females do not produce fewer female-biased offspring sex ratios when more females lay eggs on a patch. We solve this puzzle by showing that, in nature, females of Melittobia australica have a sophisticated sex ratio behavior, in which their strategy also depends on whether they have dispersed from the patch where they emerged. When females have not dispersed, they lay eggs with close relatives, which keeps local mate competition high even with multiple females, and therefore, they are selected to produce consistently female-biased sex ratios. Laboratory experiments mimic these conditions. In contrast, when females disperse, they interact with nonrelatives, and thus adjust their sex ratio depending on the number of females laying eggs. Consequently, females appear to use dispersal status as an indirect cue of relatedness and whether they should adjust their sex ratio in response to the number of females laying eggs on the patch.}, } @article {pmid33970458, year = {2021}, author = {Singletary, B}, title = {Learning Through Shared Care : Allomaternal Care Impacts Cognitive Development in Early Infancy in a Western Population.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {32}, number = {2}, pages = {326-362}, pmid = {33970458}, issn = {1936-4776}, support = {BCS-1752542//Division of Behavioral and Cognitive Sciences/ ; Reicker Grants and W & N Sullivan Scholarship Fund//School of Anthropology, University of Arizona/ ; Graduate Fellowship//Confluencenter for Creative Inquiry, University of Arizona/ ; Dissertation Research Grant//Social and Behavioral Sciences Research Institute, University of Arizona (US)/ ; Research and Project Grant//Graduate and Professional Student Council, University of Arizona (US)/ ; }, mesh = {*Cognition ; Female ; Humans ; Infant ; *Learning ; Mothers ; Surveys and Questionnaires ; }, abstract = {This study investigates how allomaternal care (AMC) impacts human development outside of energetics by evaluating relations between important qualitative and quantitative aspects of AMC and developmental outcomes in a Western population. This study seeks to determine whether there are measurable differences in cognitive and language outcomes as predicted by differences in exposure to AMC via formal (e.g., childcare facilities) and informal (e.g., family and friends) networks. Data were collected from 102 mothers and their typically developing infants aged 13-18 months. AMC predictor data were collected using questionnaires, structured daily diaries, and longitudinal interviews. Developmental outcomes were assessed using the Cognitive, Receptive Language, and Expressive Language subtests of the Bayley III Screening Test. Additional demographic covariates were also evaluated. Akaike Information Criterion (AIC)-informed model selection was used to identify the best-fitting model for each outcome across three working linear regression models. Although AMC variables had no significant effects on Receptive and Expressive Language subtest scores, highly involved familial AMC had a significant medium effect on Cognitive subtest score (β = 0.23, p < 0.01, semi-partial r = 0.28). Formal childcare had no effect on any outcome. This study provides preliminary evidence that there is a measurable connection between AMC and cognitive development in some populations and provides a methodological base from which to assess these connections cross-culturally through future studies. As these effects are attributable to AMC interactions with networks of mostly related individuals, these findings present an area for further investigation regarding the kin selection hypothesis for AMC.}, } @article {pmid33957580, year = {2021}, author = {Minnameyer, A and Strobl, V and Bruckner, S and Camenzind, DW and Van Oystaeyen, A and Wäckers, F and Williams, GR and Yañez, O and Neumann, P and Straub, L}, title = {Eusocial insect declines: Insecticide impairs sperm and feeding glands in bumblebees.}, journal = {The Science of the total environment}, volume = {785}, number = {}, pages = {146955}, doi = {10.1016/j.scitotenv.2021.146955}, pmid = {33957580}, issn = {1879-1026}, mesh = {Animals ; Bees ; Female ; Humans ; Insecta ; *Insecticides/toxicity ; Male ; Neonicotinoids/toxicity ; Nitro Compounds/toxicity ; Reproduction ; Spermatozoa ; Thiamethoxam ; }, abstract = {Insecticides are contributing to global insect declines, thereby creating demand to understand the mechanisms underlying reduced fitness. In the eusocial Hymenoptera, inclusive fitness depends on successful mating of male sexuals (drones) and efficient collaborative brood care by female workers. Therefore, sublethal insecticide effects on sperm and glands used in larval feeding (hypopharyngeal glands (HPG)) would provide key mechanisms for population declines in eusocial insects. However, while negative impacts for bumblebee colony fitness have been documented, the effects of insecticide exposure on individual physiology are less well understood. Here, we show that field-realistic concentrations (4.5-40 ng ml[-1]) of the neonicotinoid insecticide thiamethoxam significantly impair Bombus terrestris sperm and HPGs, thereby providing plausible mechanisms underlying bumblebee population decline. In the laboratory, drones and workers were exposed to five thiamethoxam concentrations (4.5 to 1000 ng ml[-1]). Then, survival, food consumption, body mass, HPG development, sperm quantity and viability were assessed. At all concentrations, drones were more exposed than workers due to higher food consumption. Increased body mass was observed in drones starting at 20 ng ml[-1] and in workers at 100 ng ml[-1]. Furthermore, environmentally realistic concentrations (4.5-40 ng ml[-1]) did not significantly affect survival or consumption for either sex. However, thiamethoxam exposure significantly negatively affected both sperm viability and HPG development at all tested concentrations. Therefore, the results indicate a trade-off between survival and fitness components, possibly due to costly detoxification. Since sperm and HPG are corner stones of colony fitness, the data offer plausible mechanisms for bumblebee population declines. To adequately mitigate ongoing biodiversity declines for the eusocial insects, this study suggests it is essential to evaluate the impact of insecticides on fitness parameters of both sexuals and workers.}, } @article {pmid33941905, year = {2021}, author = {de Boer, RA and Vega-Trejo, R and Kotrschal, A and Fitzpatrick, JL}, title = {Meta-analytic evidence that animals rarely avoid inbreeding.}, journal = {Nature ecology & evolution}, volume = {5}, number = {7}, pages = {949-964}, pmid = {33941905}, issn = {2397-334X}, mesh = {Animals ; Female ; Humans ; *Inbreeding ; Male ; *Mating Preference, Animal ; Reproduction ; }, abstract = {Animals are usually expected to avoid mating with relatives (kin avoidance) as incestuous mating can lead to the expression of inbreeding depression. Yet, theoretical models predict that unbiased mating with regards to kinship should be common, and that under some conditions, the inclusive fitness benefits associated with inbreeding can even lead to a preference for mating with kin. This mismatch between empirical and theoretical expectations generates uncertainty as to the prevalence of inbreeding avoidance in animals. Here, we synthesized 677 effect sizes from 139 experimental studies of mate choice for kin versus non-kin in diploid animals, representing 40 years of research, using a meta-analytical approach. Our meta-analysis revealed little support for the widely held view that animals avoid mating with kin, despite clear evidence of publication bias. Instead, unbiased mating with regards to kinship appears widespread across animals and experimental conditions. The significance of a variety of moderators was explored using meta-regressions, revealing that the degree of relatedness and prior experience with kin explained some variation in the effect sizes. Yet, we found no difference in kin avoidance between males and females, choice and no-choice experiments, mated and virgin animals or between humans and animals. Our findings highlight the need to rethink the widely held view that inbreeding avoidance is a given in experimental studies.}, } @article {pmid33938278, year = {2021}, author = {Schacht, R and Meeks, H and Fraser, A and Smith, KR}, title = {Was Cinderella just a fairy tale? Survival differences between stepchildren and their half-siblings.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {376}, number = {1827}, pages = {20200032}, pmid = {33938278}, issn = {1471-2970}, support = {R01 AG022095/AG/NIA NIH HHS/United States ; }, mesh = {Adolescent ; Child ; Child, Preschool ; *Family Characteristics ; Fathers/*statistics & numerical data ; Female ; Humans ; Infant ; Male ; Marriage/*statistics & numerical data ; Mortality ; Mothers/*statistics & numerical data ; Siblings/*psychology ; *Social Support ; Utah ; }, abstract = {The death of a parent, particularly the mother, is linked to a suite of negative outcomes across the life-course. Compounding concerns for child outcomes are expectations of poor treatment by step-parents after parental remarriage. Indeed, folk tales of step-parental abuse abound cross-culturally and are embedded into stories taught to children. To understand why child outcomes might be sensitive to levels of relatedness within the household, evolutionary-oriented research targets patterning in parental expenditure in ways predicted to maximize inclusive fitness. In particular, parents are expected to prioritize investments in their biological children. However, stepfamilies are only formed after children experience multiple unfortunate events (e.g. parental loss, poverty), blurring causal interpretations between step-parental presence and stepchild outcomes. Moreover, stepchildren have been shown to be integral to household functioning, caring for their half-siblings and stabilizing relationships. These results challenge narrow views of adaptive behaviour; specifically, that step-parents, unlike biological parents, do no stand to reap fitness benefits from the care that they provide to their stepchildren. To evaluate these critiques, we analyse the survival outcomes of stepchildren. We include over 400 000 individuals from across a natural fertility period (1847-1940) in the United States state of Utah and examine the consequences of parental loss and step-parental introduction. Our analyses yield three key results: (i) exposure to maternal loss in childhood is associated with elevated mortality risk, (ii) parental remarriage does not increase the risk of mortality among stepchildren compared to non-stepchildren who too had lost a parent, and (iii) stepchildren enjoy higher survival than their half-siblings within the same family. Ultimately, this work contributes to the increasingly recognized importance of cooperative relationships among non-kin for childcare and household functioning. This article is part of the theme issue 'Multidisciplinary perspectives on social support and maternal-child health'.}, } @article {pmid33934419, year = {2021}, author = {Garcia-Costoya, G and Fromhage, L}, title = {Realistic genetic architecture enables organismal adaptation as predicted under the folk definition of inclusive fitness.}, journal = {Journal of evolutionary biology}, volume = {34}, number = {7}, pages = {1087-1094}, doi = {10.1111/jeb.13795}, pmid = {33934419}, issn = {1420-9101}, mesh = {Altruism ; Biological Evolution ; Genetic Fitness ; *Models, Genetic ; Phenotype ; *Selection, Genetic ; }, abstract = {A fundamental task of evolutionary biology is to explain the pervasive impression of organismal design in nature, including traits benefiting kin. Inclusive fitness is considered by many to be a crucial piece in this puzzle, despite ongoing discussion about its scope and limitations. Here, we use individual-based simulations to study what quantity (if any) individual organisms become adapted to maximize when genetic architectures are more or less suitable for the presumed main driver of biological adaptation, namely cumulative multi-locus evolution. As an expository device, we focus on a hypothetical situation called Charlesworth's paradox, in which altruism is seemingly predicted to evolve, yet altruists immediately perish along with their altruistic genes. Our results support a recently proposed re-definition of inclusive fitness, which is concerned with the adaptive design of whole organisms as shaped by multi-locus evolution, rather than with selection for any focal gene. They also illustrate how our conceptual understanding of adaptation at the phenotypic level should inform our choice of genetic assumptions in abstract simplified models.}, } @article {pmid33908829, year = {2021}, author = {Flintham, EO and Savolainen, V and Mullon, C}, title = {Dispersal Alters the Nature and Scope of Sexually Antagonistic Variation.}, journal = {The American naturalist}, volume = {197}, number = {5}, pages = {543-559}, doi = {10.1086/713739}, pmid = {33908829}, issn = {1537-5323}, mesh = {Alleles ; *Animal Distribution ; Animals ; Female ; Genetic Drift ; *Genetic Variation ; Male ; *Selection, Genetic ; Sex Characteristics ; }, abstract = {AbstractIntralocus sexual conflict, or sexual antagonism, occurs when alleles have opposing fitness effects in the two sexes. Previous theory suggests that sexual antagonism is a driver of genetic variation by generating balancing selection. However, most of these studies assume that populations are well mixed, neglecting the effects of spatial subdivision. Here, we use mathematical modeling to show that limited dispersal changes evolution at sexually antagonistic autosomal and X-linked loci as a result of inbreeding and sex-specific kin competition. We find that if the sexes disperse at different rates, kin competition within the philopatric sex biases intralocus conflict in favor of the more dispersive sex. Furthermore, kin competition diminishes the strength of balancing selection relative to genetic drift, reducing genetic variation in small subdivided populations. Meanwhile, by decreasing heterozygosity, inbreeding reduces the scope for sexually antagonistic polymorphism due to nonadditive allelic effects, and this occurs to a greater extent on the X chromosome than autosomes. Overall, our results indicate that spatial structure is a relevant factor in predicting where sexually antagonistic alleles might be observed. We suggest that sex-specific dispersal ecology and demography can contribute to interspecific and intragenomic variation in sexual antagonism.}, } @article {pmid33878926, year = {2021}, author = {González-Forero, M and Peña, J}, title = {Eusociality through conflict dissolution.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1949}, pages = {20210386}, pmid = {33878926}, issn = {1471-2954}, mesh = {*Biological Evolution ; Female ; Pheromones ; Reproduction ; *Social Behavior ; Solubility ; }, abstract = {Eusociality, where largely unreproductive offspring help their mothers reproduce, is a major form of social organization. An increasingly documented feature of eusociality is that mothers induce their offspring to help by means of hormones, pheromones or behavioural displays, with evidence often indicating that offspring help voluntarily. The co-occurrence of maternal influence and offspring voluntary help may be explained by what we call the converted helping hypothesis, whereby maternally manipulated helping subsequently becomes voluntary. Such hypothesis requires that parent-offspring conflict is eventually dissolved-for instance, if the benefit of helping increases sufficiently over evolutionary time. We show that help provided by maternally manipulated offspring can enable the mother to sufficiently increase her fertility to transform parent-offspring conflict into parent-offspring agreement. This conflict-dissolution mechanism requires that helpers alleviate maternal life-history trade-offs, and results in reproductive division of labour, high queen fertility and honest queen signalling suppressing worker reproduction-thus exceptionally recovering diverse features of eusociality. As such trade-off alleviation seemingly holds widely across eusocial taxa, this mechanism offers a potentially general explanation for the origin of eusociality, the prevalence of maternal influence, and the offspring's willingness to help. Overall, our results explain how a major evolutionary transition can happen from ancestral conflict.}, } @article {pmid33866807, year = {2021}, author = {Oldroyd, BP and Yagound, B}, title = {Parent-of-origin effects, allele-specific expression, genomic imprinting and paternal manipulation in social insects.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {376}, number = {1826}, pages = {20200425}, pmid = {33866807}, issn = {1471-2970}, mesh = {Alleles ; Animals ; *Epigenesis, Genetic ; Genomic Imprinting ; Hymenoptera/*genetics ; Isoptera/*genetics ; *Maternal Inheritance ; *Paternal Inheritance ; Social Behavior ; }, abstract = {Haplo-diploidy and the relatedness asymmetries it generates mean that social insects are prime candidates for the evolution of genomic imprinting. In single-mating social insect species, some genes may be selected to evolve genomic mechanisms that enhance reproduction by workers when they are inherited from a female. This situation reverses in multiple mating species, where genes inherited from fathers can be under selection to enhance the reproductive success of daughters. Reciprocal crosses between subspecies of honeybees have shown strong parent-of-origin effects on worker reproductive phenotypes, and this could be evidence of such genomic imprinting affecting genes related to worker reproduction. It is also possible that social insect fathers directly affect gene expression in their daughters, for example, by placing small interfering RNA molecules in semen. Gene expression studies have repeatedly found evidence of parent-specific gene expression in social insects, but it is unclear at this time whether this arises from genomic imprinting, paternal manipulation, an artefact of cyto-nuclear interactions, or all of these. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'}, } @article {pmid33756043, year = {2021}, author = {Boots, M and Childs, D and Crossmore, J and Tidbury, H and Rudolf, V}, title = {Experimental evidence that local interactions select against selfish behaviour.}, journal = {Ecology letters}, volume = {24}, number = {6}, pages = {1187-1192}, doi = {10.1111/ele.13734}, pmid = {33756043}, issn = {1461-0248}, support = {NSF DEB- 0841686//National Science Foundation/ ; NSF DEB-1256860//National Science Foundation/ ; NIH/R01-GM122061-03/GM/NIGMS NIH HHS/United States ; NE/J009784/1//Natural Environment Research Council/ ; NIH/R01-GM122061-03/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biological Evolution ; *Cannibalism ; Larva ; Models, Biological ; *Social Behavior ; }, abstract = {How social behaviours evolve remains one of the most debated questions in evolutionary biology. An important theoretical prediction is that when organisms interact locally due to limited dispersal or strong social ties, the population structure that emerges may favour cooperation over antagonism. We carry out an experimental test of this theory by directly manipulating population spatial structure in an insect laboratory model system and measuring the impact on the evolution of the extreme selfish behaviour of cannibalism. We show that, as predicted by the theory, Indian meal moth larvae that evolved in environments with more limited dispersal are selected for lower rates of cannibalism. This is important because it demonstrates that local interactions select against selfish behaviour. Therefore, the ubiquitous variation in population structure that we see in nature is a simple mechanism that can help to explain the variation in selfish and cooperative behaviours that we see in nature.}, } @article {pmid33755538, year = {2021}, author = {Martyn, TE and Stouffer, DB and Godoy, O and Bartomeus, I and Pastore, AI and Mayfield, MM}, title = {Identifying "Useful" Fitness Models: Balancing the Benefits of Added Complexity with Realistic Data Requirements in Models of Individual Plant Fitness.}, journal = {The American naturalist}, volume = {197}, number = {4}, pages = {415-433}, doi = {10.1086/713082}, pmid = {33755538}, issn = {1537-5323}, mesh = {*Genetic Fitness ; *Models, Biological ; *Plants ; }, abstract = {AbstractDirect species interactions are commonly included in individual fitness models used for coexistence and local diversity modeling. Though widely considered important for such models, direct interactions alone are often insufficient for accurately predicting fitness, coexistence, or diversity outcomes. Incorporating higher-order interactions (HOIs) can lead to more accurate individual fitness models but also adds many model terms, which can quickly result in model overfitting. We explore approaches for balancing the trade-off between tractability and model accuracy that occurs when HOIs are added to individual fitness models. To do this, we compare models parameterized with data from annual plant communities in Australia and Spain, varying in the extent of information included about the focal and neighbor species. The best-performing models for both data sets were those that grouped neighbors based on origin status and life form, a grouping approach that reduced the number of model parameters substantially while retaining important ecological information about direct interactions and HOIs. Results suggest that the specific identity of focal or neighbor species is not necessary for building well-performing fitness models that include HOIs. In fact, grouping neighbors by even basic functional information seems sufficient to maximize model accuracy, an important outcome for the practical use of HOI-inclusive fitness models.}, } @article {pmid33755537, year = {2021}, author = {Patten, MM}, title = {On Being a Monkey's Uncle: Germline Chimerism in the Callitrichinae and the Evolution of Sibling Rivalry.}, journal = {The American naturalist}, volume = {197}, number = {4}, pages = {502-508}, doi = {10.1086/713110}, pmid = {33755537}, issn = {1537-5323}, mesh = {Animals ; *Biological Evolution ; Callitrichinae/*genetics ; *Chimerism ; Female ; Male ; *Models, Biological ; *Sibling Relations ; }, abstract = {AbstractA typical monkey of the subfamily Callitrichinae has two or more cell lineages occupying its tissues: one from "itself," and one from its co-twin(s). Chimerism originates in utero when the twin placentae fuse, vascular anastomoses form between them, and cells are exchanged between conceptuses through their shared circulation. Previously it was thought that chimerism was limited to tissues of the hematopoietic cell lineage and that the germline was clonal, but subsequent empirical work has shown that chimerism may extend to many tissues, including the germline. To explore how natural selection on chimeric organisms should shape their social behavior, I construct an inclusive fitness model of sibling interactions that permits differing degrees of chimerism in the soma and germline. The model predicts that somatic chimerism should diminish sibling rivalry but that germline chimerism should typically intensify it. A further implication of the model is the possibility for intraorganismal conflict over developing phenotypes; as tissues may differ in their extent of chimerism-for example, placenta versus brain-their respective inclusive fitness may be maximized by different phenotypes. Communication between tissues in chimeric organisms might therefore be noisy, rapidly evolving, and fraught, as is common in systems with internal evolutionary conflicts of interest.}, } @article {pmid33717435, year = {2021}, author = {Levin, SR and Grafen, A}, title = {Extending the range of additivity in using inclusive fitness.}, journal = {Ecology and evolution}, volume = {11}, number = {5}, pages = {1970-1983}, pmid = {33717435}, issn = {2045-7758}, abstract = {Inclusive fitness is a concept widely utilized by social biologists as the quantity organisms appear designed to maximize. However, inclusive fitness theory has long been criticized on the (uncontested) grounds that other quantities, such as offspring number, predict gene frequency changes accurately in a wider range of mathematical models. Here, we articulate a set of modeling assumptions that extend the range of scenarios in which inclusive fitness can be applied. We reanalyze recent formal analyses that searched for, but did not find, inclusive fitness maximization. We show (a) that previous models have not used Hamilton's definition of inclusive fitness, (b) a reinterpretation of Hamilton's definition that makes it usable in this context, and (c) that under the assumption of probabilistic mixing of phenotypes, inclusive fitness is indeed maximized in these models. We also show how to understand mathematically, and at an individual level, the definition of inclusive fitness, in an explicit population genetic model in which exact additivity is not assumed. We hope that in articulating these modeling assumptions and providing formal support for inclusive fitness maximization, we help bridge the gap between empiricists and theoreticians, which in some ways has been widening, demonstrating to mathematicians why biologists are content to use inclusive fitness, and offering one way to utilize inclusive fitness in general models of social behavior.}, } @article {pmid33678027, year = {2021}, author = {Galimov, ER and Gems, D}, title = {Death happy: adaptive ageing and its evolution by kin selection in organisms with colonial ecology.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {376}, number = {1823}, pages = {20190730}, pmid = {33678027}, issn = {1471-2970}, support = {/WT_/Wellcome Trust/United Kingdom ; 215574/Z/19/Z/WT_/Wellcome Trust/United Kingdom ; 098565/Z/12/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {*Adaptation, Biological ; *Aging ; Animals ; Biological Coevolution ; *Biological Evolution ; Caenorhabditis elegans/*physiology ; Fishes/*physiology ; Life History Traits ; *Selection, Genetic ; }, abstract = {Standard evolutionary theory, supported by mathematical modelling of outbred, dispersed populations predicts that ageing is not an adaptation. We recently argued that in clonal, viscous populations, programmed organismal death could promote fitness through social benefits and has, in some organisms (e.g. Caenorhabditis elegans), evolved to shorten lifespan. Here, we review previous adaptive death theory, including consumer sacrifice, biomass sacrifice and defensive sacrifice types of altruistic adaptive death. In addition, we discuss possible adaptive death in certain semelparous fish, coevolution of reproductive and adaptive death, and adaptive reproductive senescence in C. elegans. We also describe findings from recent tests for the existence of adaptive death in C. elegans using computer modelling. Such models have provided new insights into how trade-offs between fitness at the individual and colony levels mean that senescent changes can be selected traits. Exploring further the relationship between adaptive death and social interactions, we consider examples where adaptive death results more from action of kin than from self-destructive mechanisms and, to describe this, introduce the term adaptive killing of kin. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'}, } @article {pmid33678025, year = {2021}, author = {Heinze, J and Giehr, J}, title = {The plasticity of lifespan in social insects.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {376}, number = {1823}, pages = {20190734}, pmid = {33678025}, issn = {1471-2970}, mesh = {Animals ; Ants/*physiology ; Bees/*physiology ; Fertility ; Genetic Fitness ; *Life History Traits ; Longevity ; }, abstract = {One of the central questions of ageing research is why lifespans of organisms differ so tremendously among related taxa and, even more surprising, among members of the same species. Social insects provide a particularly pronounced example for this. Here, we review previously published information on lifespan plasticity in social insects and provide new data on worker lifespan in the ant Cardiocondyla obscurior, which because of its relatively short lifespan is a convenient model to study ageing. We show that individual lifespan may vary within species with several reproductive and social traits, such as egg-laying rate, queen number, task, colony size and colony composition. For example, in Cardiocondyla, highly fecund queens live longer than reproductively less active queens, and workers tend to live longer when transferred into a novel social environment or, as we show with new data, into small colonies. We hypothesize that this plasticity of lifespan serves to maximize the reproductive output of the colony as a whole and thus the inclusive fitness of all individuals. The underlying mechanisms that link the social environment or reproductive status with lifespan are currently unresolved. Several studies in honeybees and ants indicate an involvement of nutrient-sensing pathways, but the details appear to differ among species. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'}, } @article {pmid33667486, year = {2021}, author = {Wu, R and Wu, X and Li, S and Li, G and Jiang, Z and Zhong, H and Wang, B and Yang, S and Wei, W}, title = {Predator odor exposure increases social contact in adolescents and parental behavior in adulthood in Brandt's voles.}, journal = {Behavioural processes}, volume = {186}, number = {}, pages = {104372}, doi = {10.1016/j.beproc.2021.104372}, pmid = {33667486}, issn = {1872-8308}, mesh = {Animals ; *Arvicolinae ; Behavior, Animal ; Female ; Male ; *Odorants ; Rabbits ; Social Behavior ; Weaning ; }, abstract = {Research suggests that predation risk during adolescence can program adult stress response and emotional behavior; however, little is known about the short-term and lasting residual effects of this experience on social behavior. We explored this concept in social Brandt's voles (Lasiopodomys brandtii). Adolescent male and female voles were exposed to distilled water, rabbit urine (as a non-predator stimulus), and cat urine for 60 min daily from postnatal day (PND) 28-49. Social play tests were conducted immediately following exposure on PND 28, 35, 42, and 49. In the social play test, repeated cat odor (CO) exposure enhanced the contact behavior of voles with their cagemate. Adolescent exposure to CO did not affect behavioral responses toward unrelated pups in the alloparental behavior test or same-sex individuals in the social interaction test. However, exposure to CO significantly enhanced the licking/grooming behavior of voles towards their own pups in the home cage parental behavior test. Repeated CO exposure significantly inhibited weight gain in male voles during adolescence. This effect was transmitted to the next generation, with lower weight gain in offspring before weaning. Following repeated CO exposure, males tended to have more female offspring whereas females produced more offspring, suggesting an adaptive strategy to increase inclusive fitness under predatory risk. These findings demonstrate that adolescent exposure to predatory risk augments adolescent social contact and adult parental behavior and suggest a role for improved inclusive fitness in mediating long-term outcomes.}, } @article {pmid33589803, year = {2021}, author = {Kennedy, P and Sumner, S and Botha, P and Welton, NJ and Higginson, AD and Radford, AN}, title = {Diminishing returns drive altruists to help extended family.}, journal = {Nature ecology & evolution}, volume = {5}, number = {4}, pages = {468-479}, pmid = {33589803}, issn = {2397-334X}, support = {G0802413/MRC_/Medical Research Council/United Kingdom ; 682253/ERC_/European Research Council/International ; }, mesh = {*Altruism ; Animals ; Family ; Humans ; Social Interaction ; *Wasps ; }, abstract = {Altruism between close relatives can be easily explained. However, paradoxes arise when organisms divert altruism towards more distantly related recipients. In some social insects, workers drift extensively between colonies and help raise less related foreign brood, seemingly reducing inclusive fitness. Since being highlighted by W. D. Hamilton, three hypotheses (bet hedging, indirect reciprocity and diminishing returns to cooperation) have been proposed for this surprising behaviour. Here, using inclusive fitness theory, we show that bet hedging and indirect reciprocity could only drive cooperative drifting under improbable conditions. However, diminishing returns to cooperation create a simple context in which sharing workers is adaptive. Using a longitudinal dataset comprising over a quarter of a million nest cell observations, we quantify cooperative payoffs in the Neotropical wasp Polistes canadensis, for which drifting occurs at high levels. As the worker-to-brood ratio rises in a worker's home colony, the predicted marginal benefit of a worker for expected colony productivity diminishes. Helping related colonies can allow effort to be focused on related brood that are more in need of care. Finally, we use simulations to show that cooperative drifting evolves under diminishing returns when dispersal is local, allowing altruists to focus their efforts on related recipients. Our results indicate the power of nonlinear fitness effects to shape social organization, and suggest that models of eusocial evolution should be extended to include neglected social interactions within colony networks.}, } @article {pmid33583398, year = {2021}, author = {Wang, L and Cornell, SJ and Speed, MP and Arbuckle, K}, title = {Coevolution of group-living and aposematism in caterpillars: warning colouration may facilitate the evolution from group-living to solitary habits.}, journal = {BMC ecology and evolution}, volume = {21}, number = {1}, pages = {25}, pmid = {33583398}, issn = {2730-7182}, mesh = {Animals ; Biological Evolution ; *Biological Mimicry ; Habits ; Larva ; Phylogeny ; *Predatory Behavior ; }, abstract = {BACKGROUND: Animals use diverse antipredator mechanisms, including visual signalling of aversive chemical defence (aposematism). However, the initial evolution of aposematism poses the problem that the first aposematic individuals are conspicuous to predators who have not learned the significance of the warning colouration. In one scenario, aposematism evolves in group-living species and originally persisted due to kin selection or positive frequency-dependent selection in groups. Alternatively, group-living might evolve after aposematism because grouping can amplify the warning signal. However, our current understanding of the evolutionary dynamics of these traits is limited, leaving the relative merit of these scenarios unresolved.

RESULTS: We used a phylogenetic comparative approach to estimate phenotypic evolutionary models to enable inferences regarding ancestral states and trait dynamics of grouping and aposematic colouration in a classic model system (caterpillars). We find strong support for aposematism at the root of the clade, and some (but weaker) support for ancestral solitary habits. Transition rates between aposematism and crypsis are generally higher than those between group-living and solitary-living, suggesting that colouration is more evolutionarily labile than aggregation. We also find that the transition from group-living to solitary-living states can only happen in aposematic lineage, suggesting that aposematism facilitates the evolution of solitary caterpillars, perhaps due to the additional protection offered when the benefits of grouping are lost. We also find that the high frequency of solitary, cryptic caterpillars is because this state is particularly stable, in that the transition rates moving towards this state are substantially higher than those moving away from it, favouring its accumulation in the clade over evolutionary time.

CONCLUSIONS: Our results provide new insights into the coevolution of colour and aggregation in caterpillars. We find support for an aposematic caterpillar at the root of this major clade, and for the signal augmentation hypothesis as an explanation of the evolution of aposematic, group-living caterpillars. We find that colouration is more labile than aggregation behaviour, but that the combination of solitary and cryptic habits is particularly stable. Finally, our results reveal that the transitions from group-living to solitary-living could be facilitated by aposematism, providing a new link between these well-studied traits.}, } @article {pmid33563093, year = {2021}, author = {Barragan-Jason, G and Cauchoix, M and Regnier, A and Bourjade, M and Hopfensitz, A and Chaine, AS}, title = {Schoolchildren cooperate more successfully with non-kin than with siblings.}, journal = {Proceedings. Biological sciences}, volume = {288}, number = {1944}, pages = {20202951}, pmid = {33563093}, issn = {1471-2954}, mesh = {Adult ; Child ; Child, Preschool ; Cooperative Behavior ; Friends ; Humans ; *Interpersonal Relations ; *Siblings ; Social Networking ; }, abstract = {Cooperation plays a key role in the development of advanced societies and can be stabilized through shared genes (kinship) or reciprocation. In humans, cooperation among kin occurs more readily than cooperation among non-kin. In many organisms, cooperation can shift with age (e.g. helpers at the nest); however, little is known about developmental shifts between kin and non-kin cooperation in humans. Using a cooperative game, we show that 3- to 10-year-old French schoolchildren cooperated less successfully with siblings than with non-kin children, whether or not non-kin partners were friends. Furthermore, children with larger social networks cooperated better and the perception of friendship among non-friends improved after cooperating. These results contrast with the well-established preference for kin cooperation among adults and indicate that non-kin cooperation in humans might serve to forge and extend non-kin social relationships during middle childhood and create opportunities for future collaboration beyond kin. Our results suggest that the current view of cooperation in humans may only apply to adults and that future studies should focus on how and why cooperation with different classes of partners might change during development in humans across cultures as well as other long-lived organisms.}, } @article {pmid33526674, year = {2021}, author = {Simonet, C and McNally, L}, title = {Kin selection explains the evolution of cooperation in the gut microbiota.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {118}, number = {6}, pages = {}, pmid = {33526674}, issn = {1091-6490}, mesh = {Bacteria/classification/*genetics/growth & development ; Ecosystem ; *Evolution, Molecular ; Gastrointestinal Microbiome/*genetics ; Genetic Fitness/genetics ; Genome, Bacterial/genetics ; Humans ; Microbiota/*genetics ; Phylogeny ; Reproduction/genetics ; Selection, Genetic/genetics ; }, abstract = {Through the secretion of "public goods" molecules, microbes cooperatively exploit their habitat. This is known as a major driver of the functioning of microbial communities, including in human disease. Understanding why microbial species cooperate is therefore crucial to achieve successful microbial community management, such as microbiome manipulation. A leading explanation is that of Hamilton's inclusive-fitness framework. A cooperator can indirectly transmit its genes by helping the reproduction of an individual carrying similar genes. Therefore, all else being equal, as relatedness among individuals increases, so should cooperation. However, the predictive power of relatedness, particularly in microbes, is surrounded by controversy. Using phylogenetic comparative analyses across the full diversity of the human gut microbiota and six forms of cooperation, we find that relatedness is predictive of the cooperative gene content evolution in gut-microbe genomes. Hence, relatedness is predictive of cooperation over broad microbial taxonomic levels that encompass variation in other life-history and ecology details. This supports the generality of Hamilton's central insights and the relevance of relatedness as a key parameter of interest to advance microbial predictive and engineering science.}, } @article {pmid33523789, year = {2021}, author = {Kennedy, P and Radford, AN}, title = {Kin Blackmail as a Coercive Route to Altruism.}, journal = {The American naturalist}, volume = {197}, number = {2}, pages = {266-273}, doi = {10.1086/712349}, pmid = {33523789}, issn = {1537-5323}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; *Coercion ; Genetic Fitness ; Social Behavior ; }, abstract = {AbstractThe evolution of altruism (helping a recipient at personal cost) often involves conflicts of interest. Recipients frequently prefer greater altruism than actors are prepared to provide. Coercion by recipients normally involves limiting an actor's options. Here, we consider the possibility of a coercive recipient limiting its own options. Forty years ago, Amotz Zahavi suggested that nesting birds may be "blackmailed" into increased parental care if offspring threaten to harm themselves (and therefore jeopardize the direct fitness of their parents). In a simple kin selection model, we expand blackmail to indirect fitness and highlight that blackmail can occur between any kin to drive reproductive division of labor. In principle, a recipient may place its own fitness at risk (brinkmanship), imposing sanctions on a relative's indirect fitness if the relative fails to cooperate. To use its own survival or reproduction as leverage in a sequential game, a recipient must increase the extent to which its existing fitness depends on the actor's behavior and therefore credibly commit to a cost if the actor does not comply. As it requires opportunities for commitment, kin blackmail can arise only under stringent conditions, but existing kin blackmailers may pass unnoticed because of their strategic success.}, } @article {pmid33522615, year = {2021}, author = {Anten, NPR and Chen, BJW}, title = {Detect thy family: Mechanisms, ecology and agricultural aspects of kin recognition in plants.}, journal = {Plant, cell & environment}, volume = {44}, number = {4}, pages = {1059-1071}, pmid = {33522615}, issn = {1365-3040}, mesh = {Communication ; *Crop Production ; *Ecology ; Plant Physiological Phenomena ; Plant Roots/physiology ; Plants/*metabolism ; }, abstract = {The phenomenon that organisms can distinguish genetically related individuals from strangers (i.e., kin recognition) and exhibit more cooperative behaviours towards their relatives (i.e., positive kin discrimination) has been documented in a wide variety of organisms. However, its occurrence in plants has been considered only recently. Despite the concerns about some methodologies used to document kin recognition, there is sufficient evidence to state that it exists in plants. Effects of kin recognition go well beyond reducing resource competition between related plants and involve interactions with symbionts (e.g., mycorrhizal networks). Kin recognition thus likely has important implications for evolution of plant traits, diversity of plant populations, ecological networks and community structures. Moreover, as kin selection may result in less competitive traits and thus greater population performance, it holds potential promise for crop breeding. Exploration of these evo-ecological and agricultural implications requires adequate control and measurements of relatedness, sufficient replication at genotypic level and comprehensive measurements of performance/fitness effects of kin discrimination. The primary questions that need to be answered are: when, where and by how much positive kin discrimination improves population performance.}, } @article {pmid33508326, year = {2021}, author = {Avila, P and Priklopil, T and Lehmann, L}, title = {Hamilton's rule, gradual evolution, and the optimal (feedback) control of phenotypically plastic traits.}, journal = {Journal of theoretical biology}, volume = {526}, number = {}, pages = {110602}, doi = {10.1016/j.jtbi.2021.110602}, pmid = {33508326}, issn = {1095-8541}, mesh = {*Biological Evolution ; Feedback ; Game Theory ; Humans ; Phenotype ; *Selection, Genetic ; }, abstract = {Most traits expressed by organisms, such as gene expression profiles, developmental trajectories, behavioural sequences and reaction norms are function-valued traits (colloquially "phenotypically plastic traits"), since they vary across an individual's age and in response to various internal and/or external factors (state variables). Furthermore, most organisms live in populations subject to limited genetic mixing and are thus likely to interact with their relatives. We here formalise selection on genetically determined function-valued traits of individuals interacting in a group-structured population, by deriving the marginal version of Hamilton's rule for function-valued traits. This rule simultaneously gives a condition for the invasion of an initially rare mutant function-valued trait and its ultimate fixation in the population (invasion thus implies substitution). Hamilton's rule thus underlies the gradual evolution of function-valued traits and gives rise to necessary first-order conditions for their uninvadability (evolutionary stability). We develop a novel analysis using optimal control theory and differential game theory, to simultaneously characterise and compare the first-order conditions of (i) open-loop traits - functions of time (or age) only, and (ii) closed-loop (state-feedback) traits - functions of both time and state variables. We show that closed-loop traits can be represented as the simpler open-loop traits when individuals do not interact or when they interact with clonal relatives. Our analysis delineates the role of state-dependence and interdependence between individuals for trait evolution, which has implications to both life-history theory and social evolution.}, } @article {pmid33491804, year = {2021}, author = {Correia, HE and Abebe, A and Dobson, FS}, title = {Multiple paternity and the number of offspring: A model reveals two major groups of species.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {43}, number = {4}, pages = {e2000247}, doi = {10.1002/bies.202000247}, pmid = {33491804}, issn = {1521-1878}, mesh = {Animals ; Bayes Theorem ; Mammals ; *Microsatellite Repeats/genetics ; *Paternity ; Reproduction ; Sexual Behavior, Animal ; }, abstract = {Parentage analyses via microsatellite markers have revealed multiple paternity within the broods of polytocous species of mammals, reptiles, amphibians, fishes and invertebrates. The widespread phenomenon of multiple paternity may have attending relationships with such evolutionary processes as sexual selection and kin selection. However, just how much multiple paternity should a species exhibit? We developed Bayesian null models of how multiple paternity relates to brood sizes. For each of 114 species with published data on brood sizes and numbers of sires, we compared our null model estimates to published frequencies of multiple paternity. The majority of species fell close to our null model, especially among fish and invertebrate species. Some species, however, had low probabilities of multiple paternity, far from the predictions of the null model, likely due to sexual selection and environmental constraints. We suggest a major division among species' mating systems between those with close to random mating and high levels of multiple paternity, and those with constraints that produce low levels of multiple paternity.}, } @article {pmid33459427, year = {2021}, author = {Rueger, T and Buston, PM and Bogdanowicz, SM and Wong, MY}, title = {Genetic relatedness in social groups of the emerald coral goby Paragobiodon xanthosoma creates potential for weak kin selection.}, journal = {Molecular ecology}, volume = {30}, number = {5}, pages = {1311-1321}, doi = {10.1111/mec.15809}, pmid = {33459427}, issn = {1365-294X}, mesh = {Animals ; *Anthozoa ; Microsatellite Repeats/genetics ; Papua New Guinea ; *Perciformes/genetics ; Selection, Genetic ; Social Behavior ; *Xanthosoma ; }, abstract = {Animals forming social groups that include breeders and nonbreeders present evolutionary paradoxes; why do breeders tolerate nonbreeders? And why do nonbreeders tolerate their situation? Both paradoxes are often explained with kin selection. Kin selection is, however, assumed to play little or no role in social group formation of marine organisms with dispersive larval phases. Yet, in some marine organisms, recent evidence suggests small-scale patterns of relatedness, meaning that this assumption must always be tested. Here, we investigated the genetic relatedness of social groups of the emerald coral goby, Paragobiodon xanthosoma. We genotyped 73 individuals from 16 groups in Kimbe Bay, Papua New Guinea, at 20 microsatellite loci and estimated pairwise relatedness among all individuals. We found that estimated pairwise relatedness among individuals within groups was significantly higher than the pairwise relatedness among individuals from the same reef, and pairwise relatedness among individuals from the same reef was significantly higher than the pairwise relatedness among individuals from different reefs. This spatial signature suggests that there may be very limited dispersal in this species. The slightly positive relatedness within groups creates the potential for weak kin selection, which may help to resolve the paradox of why breeders tolerate subordinates in P. xanthosoma. The other paradox, why nonbreeders tolerate their situation, is better explained by alternative hypotheses such as territory inheritance, and ecological and social constraints. We show that even in marine animals with dispersive larval phases, kin selection needs to be considered to explain the evolution of complex social groups.}, } @article {pmid33457190, year = {2020}, author = {Seitz, BM and Polack, CW and Miller, RR}, title = {Adaptive Memory: Generality of the Parent Processing Effect and Effects of Biological Relatedness on Recall.}, journal = {Evolutionary psychological science}, volume = {6}, number = {3}, pages = {246-260}, pmid = {33457190}, issn = {2198-9885}, support = {R01 MH033881/MH/NIMH NIH HHS/United States ; }, abstract = {The adaptive memory framework posits that human memory is an evolved cognitive feature, in which stimuli relevant to fitness are better remembered than neutral stimuli. There is now substantial evidence that processing a neutral stimulus in terms of its relevancy to an imagined ancestral survival scenario enhances recall, although there is still disagreement concerning the proximate mechanisms responsible for this effect. Several other mnemonic biases have recently been discovered that similarly appear to reflect evolutionary pressures, including a bias to remember items relevant to an imagined parenting scenario. We tested the generality of this parent processing effect by varying the biological relatedness of the imagined child. We also varied the biological relatedness of a child during an imagined third-person survival processing scenario. Across four experiments, we found evidence that simply altering the described biological relatedness of a child in the parenting scenario and third-person survival processing scenario can affect recall, such that items are better remembered when made relevant to a biological child compared to an adopted child. How these findings inform the general adaptive memory framework is discussed.}, } @article {pmid33411951, year = {2021}, author = {Gutiérrez, EG and Vivas-Toro, I and Carmona-Ruíz, D and Villalobos-Chaves, D and Rodríguez-Herrera, B and Real-Monroy, MD and León-Avila, G and Ortega, J}, title = {Socio-spatial organization reveals paternity and low kinship in the Honduran white bat (Ectophylla alba) in Costa Rica.}, journal = {Integrative zoology}, volume = {16}, number = {5}, pages = {646-658}, doi = {10.1111/1749-4877.12514}, pmid = {33411951}, issn = {1749-4877}, mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; Chiroptera/*genetics/physiology ; Costa Rica ; Female ; Male ; *Paternity ; Social Behavior ; }, abstract = {Ectophylla alba is a tent-making bat that roosts in mixed-sex clusters comprising adults and offspring. Our goal was to determine the genetic identity of individuals belonging to different roosting groups. We tested the hypothesis of kin selection as a major force structuring group composition. We used 9 microsatellites designed for E. alba to determine the genetic identity and probability of parentage of individuals. We analyzed parentage and kinship using the software ML-Relate, GenAIEx, and Cervus. The obtained relationship probabilities (0.5) revealed a clear maternal relationship between female adults and offspring with allele compatibility, and at least 5 relationships between male adults and pups. We found a low degree of relatedness within roosting groups. Between roosting groups at different sites, the mean probability of a half-sibling relationship ranged from 0.214 to 0.244 and, for full-sibling relationship, from 0.383 to 0.553. Genetically, adult individuals were poorly related within clusters, and kinship as an evolutionary force could not explain group membership.}, } @article {pmid33338428, year = {2021}, author = {Siracusa, ER and Boutin, S and Dantzer, B and Lane, JE and Coltman, DW and McAdam, AG}, title = {Familiar Neighbors, but Not Relatives, Enhance Fitness in a Territorial Mammal.}, journal = {Current biology : CB}, volume = {31}, number = {2}, pages = {438-445.e3}, doi = {10.1016/j.cub.2020.10.072}, pmid = {33338428}, issn = {1879-0445}, mesh = {Animals ; *Evolution, Molecular ; Female ; *Genetic Fitness ; Homing Behavior ; Male ; Sciuridae/*physiology ; *Social Behavior ; }, abstract = {One of the outstanding questions in evolutionary biology is the extent to which mutually beneficial interactions and kin selection can facilitate the evolution of cooperation by mitigating conflict between interacting organisms. The indirect fitness benefits gained from associating with kin are an important pathway to conflict resolution,[1] but conflict can also be resolved if individuals gain direct benefits from cooperating with one another (e.g., mutualism or reciprocity).[2] Because of the kin-structured nature of many animal societies, it has been difficult for previous research to assess the relative importance of these mechanisms.[3-5] However, one area that might allow for the relative roles of kin selection and mutualistic benefits to be disentangled is in the resolution of conflict over territorial space.[6] Although much research has focused on group-living species, the question of how cooperation can first be favored in solitary, territorial species remains a key question. Using 22 years of data from a population of North American red squirrels, we assessed how kinship and familiarity with neighbors affected fitness in a territorial mammal. Although living near kin did not enhance fitness, familiarity with neighbors increased survival and annual reproductive success. These fitness benefits were strong enough to compensate for the effects of aging later in life and have potential consequences for the evolution of senescence. We suggest that such substantial fitness benefits provide the opportunity for the evolution of cooperation between adversarial neighbors, offering insight into the role that mutually beneficial behaviors might play in facilitating and stabilizing social systems.}, } @article {pmid33326651, year = {2021}, author = {Galbraith, DA and Ma, R and Grozinger, CM}, title = {Tissue-specific transcription patterns support the kinship theory of intragenomic conflict in honey bees (Apis mellifera).}, journal = {Molecular ecology}, volume = {30}, number = {4}, pages = {1029-1041}, doi = {10.1111/mec.15778}, pmid = {33326651}, issn = {1365-294X}, mesh = {Animals ; Bees/genetics ; Brain ; Gene Expression ; *Gene Regulatory Networks ; *Reproduction ; }, abstract = {Kin selection may act differently on genes inherited from parents (matrigenes and patrigenes), resulting in intragenomic conflict. This conflict can be observed as differential expression of matrigenes and patrigenes, or parent-specific gene expression (PSGE). In honey bees (Apis mellifera), intragenomic conflict is hypothesized to occur in multiple social contexts. Previously, we found that patrigene-biased expression in reproductive tissues was associated with increased reproductive potential in worker honey bees, consistent with the prediction that patrigenes are selected to promote selfish behaviour in this context. Here, we examined brain gene expression patterns to determine if PSGE is also found in other tissues. As before, the number of transcripts showing patrigene expression bias was significantly greater in the brains of reproductive vs. sterile workers, while the number of matrigene-biased transcripts was not significantly different. Twelve transcripts out of the 374 showing PSGE in either tissue showed PSGE in both brain and reproductive tissues; this overlap was significantly greater than expected by chance. However, the majority of transcripts show PSGE only in one tissue, suggesting the epigenetic mechanisms mediating PSGE exhibit plasticity between tissues. There was no significant overlap between transcripts that showed PSGE and transcripts that were significantly differentially expressed. Weighted gene correlation network analysis identified modules which were significantly enriched in both types of transcripts, suggesting that these genes may influence each other through gene networks. Our results provide further support for the kin selection theory of intragenomic conflict, and provide valuable insights into the mechanisms which may mediate this process.}, } @article {pmid33318799, year = {2020}, author = {Arnot, M and Brandl, E and Campbell, OLK and Chen, Y and Du, J and Dyble, M and Emmott, EH and Ge, E and Kretschmer, LDW and Mace, R and Micheletti, AJC and Nila, S and Peacey, S and Salali, GD and Zhang, H}, title = {How evolutionary behavioural sciences can help us understand behaviour in a pandemic.}, journal = {Evolution, medicine, and public health}, volume = {2020}, number = {1}, pages = {264-278}, pmid = {33318799}, issn = {2050-6201}, abstract = {The COVID-19 pandemic has brought science into the public eye and to the attention of governments more than ever before. Much of this attention is on work in epidemiology, virology and public health, with most behavioural advice in public health focusing squarely on 'proximate' determinants of behaviour. While epidemiological models are powerful tools to predict the spread of disease when human behaviour is stable, most do not incorporate behavioural change. The evolutionary basis of our preferences and the cultural evolutionary dynamics of our beliefs drive behavioural change, so understanding these evolutionary processes can help inform individual and government decision-making in the face of a pandemic. Lay summary: The COVID-19 pandemic has brought behavioural sciences into the public eye: Without vaccinations, stopping the spread of the virus must rely on behaviour change by limiting contact between people. On the face of it, "stop seeing people" sounds simple. In practice, this is hard. Here we outline how an evolutionary perspective on behaviour change can provide additional insights. Evolutionary theory postulates that our psychology and behaviour did not evolve to maximize our health or that of others. Instead, individuals are expected to act to maximise their inclusive fitness (i.e, spreading our genes) - which can lead to a conflict between behaviours that are in the best interests for the individual, and behaviours that stop the spread of the virus. By examining the ultimate explanations of behaviour related to pandemic-management (such as behavioural compliance and social distancing), we conclude that "good of the group" arguments and "one size fits all" policies are unlikely to encourage behaviour change over the long-term. Sustained behaviour change to keep pandemics at bay is much more likely to emerge from environmental change, so governments and policy makers may need to facilitate significant social change - such as improving life experiences for disadvantaged groups.}, } @article {pmid37588542, year = {2021}, author = {Gehrig, S and Mesoudi, A and Lamba, S}, title = {Banking on cooperation: an evolutionary analysis of microfinance loan repayment behaviour.}, journal = {Evolutionary human sciences}, volume = {3}, number = {}, pages = {e2}, pmid = {37588542}, issn = {2513-843X}, abstract = {Microfinance is an economic development tool that provides loans to low-income borrowers to stimulate economic growth and reduce financial hardship. Lenders typically require joint liability, where multiple borrowers share the responsibility of repaying a group loan. We propose that this lending practice creates a cooperation dilemma similar to that faced by humans and other organisms in nature across many domains. This could offer a real-world test case for evolutionary theories of cooperation from the biological sciences. In turn, such theories could provide new insights into loan repayment behaviour. We first hypothesise how group loan repayment efficacy should be affected by mechanisms of assortment from the evolutionary literature on cooperation, i.e. common ancestry (kin selection), prior interaction (reciprocity), partner choice, similarity of tags, social learning, and ecology and demography. We then assess selected hypotheses by reviewing 41 studies from 32 countries on micro-borrowers' loan repayment, evaluating which characteristics of borrowers are associated with credit repayment behaviour. Surprisingly, we find that kinship is mostly negatively associated with repayment efficacy, but prior interaction and partner choice are both more positively associated. Our work highlights the scope of evolutionary theory to provide systematic insight into how humans respond to novel economic institutions and interventions.}, } @article {pmid33283689, year = {2021}, author = {Tanskanen, AO and Danielsbacka, M}, title = {Grandmaternal investment and early childhood injury: the role of X-chromosomal relatedness.}, journal = {Journal of biosocial science}, volume = {53}, number = {6}, pages = {968-971}, doi = {10.1017/S0021932020000711}, pmid = {33283689}, issn = {1469-7599}, mesh = {Biological Evolution ; Child ; Child, Preschool ; Cohort Studies ; Family ; *Grandparents ; Humans ; Infant ; }, abstract = {Evolutionary theory posits that grandmothers can increase their inclusive fitness by investing time and resources in their grandchildren. According on the X-linked grandmother hypothesis, the asymmetric inheritance of X-chromosomes should be responsible for the biased effect of the investment by maternal and paternal grandmothers towards granddaughters and grandsons. The British Millennium Cohort Study (n=4445 children) was used to investigate the association between grandmaternal childcare and children's injuries between the ages of 9 months and 3 years. Support was found for the X-linked grandmother hypothesis predicting that the investment of paternal grandmothers benefits more granddaughters than grandsons, the investment of paternal grandmothers benefits granddaughters more than the investment of maternal grandmothers, and the investment of maternal grandmothers is similarly associated with the injuries of granddaughters and grandsons. However, no support was found for the prediction that maternal grandmothers benefit more grandsons than paternal grandmothers. Thus, some, although not univocal, evidence for the prediction that X-chromosomal relatedness shapes the grandmaternal effect on child outcomes was found.}, } @article {pmid33253458, year = {2021}, author = {Ndhlovu, A and Durand, PM and Ramsey, G}, title = {Programmed cell death as a black queen in microbial communities.}, journal = {Molecular ecology}, volume = {30}, number = {5}, pages = {1110-1119}, doi = {10.1111/mec.15757}, pmid = {33253458}, issn = {1365-294X}, mesh = {*Apoptosis ; *Microbiota/genetics ; }, abstract = {Programmed cell death (PCD) in unicellular organisms is in some instances an altruistic trait. When the beneficiaries are clones or close kin, kin selection theory may be used to explain the evolution of the trait, and when the trait evolves in groups of distantly related individuals, group or multilevel selection theory is invoked. In mixed microbial communities, the benefits are also available to unrelated taxa. But the evolutionary ecology of PCD in communities is poorly understood. Few hypotheses have been offered concerning the community role of PCD despite its far-reaching effects. The hypothesis we consider here is that PCD is a black queen. The Black Queen Hypothesis (BQH) outlines how public goods arising from a leaky function are exploited by other taxa in the community. Black Queen (BQ) traits are essential for community survival, but only some members bear the cost of possessing them, while others lose the trait In addition, BQ traits have been defined in terms of adaptive gene loss, and it is unknown whether this has occurred for PCD. Our conclusion is that PCD fulfils the two most important criteria of a BQ (leakiness and costliness), but that more empirical data are needed for assessing the remaining two criteria. In addition, we hold that for viewing PCD as a BQ, the original BQH needs to include social traits. Thus, despite some empirical and conceptual shortcomings, the BQH provides a helpful avenue for investigating PCD in microbial communities.}, } @article {pmid33238064, year = {2021}, author = {Rodrigues, AMM and Estrela, S and Brown, SP}, title = {Community lifespan, niche expansion and the evolution of interspecific cooperation.}, journal = {Journal of evolutionary biology}, volume = {34}, number = {2}, pages = {352-363}, doi = {10.1111/jeb.13739}, pmid = {33238064}, issn = {1420-9101}, mesh = {*Biological Evolution ; *Ecosystem ; *Models, Genetic ; Symbiosis/*genetics ; }, abstract = {Microbes live in dense and diverse communities where they deploy many traits that promote the growth and survival of neighbouring species, all the while also competing for shared resources. Because microbial communities are highly dynamic, the costs and benefits of species interactions change over the growth cycle of a community. How mutualistic interactions evolve under such demographic and ecological conditions is still poorly understood. Here, we develop an eco-evolutionary model to explore how different forms of helping with distinct fitness effects (rate-enhancing and yield-enhancing) affect the multiple phases of community growth, and its consequences for the evolution of mutualisms. We specifically focus on a form of yield-enhancing trait in which cooperation augments the common pool of resources, termed niche expansion. We show that although mutualisms in which cooperation increases partners growth rate are generally favoured at early stages of community growth, niche expansion can evolve at later stages where densities are high. Further, we find that niche expansion can promote the evolution of reproductive restraint, in which a focal species adaptively reduces its own growth rate to increase the density of partner species. Our findings suggest that yield-enhancing mutualisms are more prevalent in stable habitats with a constant supply of resources, and where populations typically live at high densities. In general, our findings highlight the need to integrate different components of population growth in the analysis of mutualisms to understand the composition and function of microbial communities.}, } @article {pmid33179250, year = {2020}, author = {Benler, S and Koonin, EV}, title = {Phage lysis-lysogeny switches and programmed cell death: Danse macabre.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {42}, number = {12}, pages = {e2000114}, doi = {10.1002/bies.202000114}, pmid = {33179250}, issn = {1521-1878}, mesh = {Apoptosis ; Bacteriophage lambda/genetics ; *Bacteriophages/genetics ; Clustered Regularly Interspaced Short Palindromic Repeats ; *Lysogeny ; Virus Latency ; }, abstract = {Exploration of immune systems in prokaryotes, such as restriction-modification or CRISPR-Cas, shows that both innate and adaptive systems possess programmed cell death (PCD) potential. The key outstanding question is how the immune systems sense and "predict" infection outcomes to "decide" whether to fight the pathogen or induce PCD. There is a striking parallel between this life-or-death decision faced by the cell and the decision by temperate viruses to protect or kill their hosts, epitomized by the lysis-lysogeny switch of bacteriophage Lambda. Immune systems and temperate phages sense the same molecular inputs, primarily, DNA damage, that determine whether the cell lives or dies. Because temperate (pro)phages are themselves components of prokaryotic genomes, their shared "interests" with the hosts result in coregulation of the lysis-lysogeny switch and immune systems that jointly provide the cell with the decision machinery to probe and predict infection outcomes, answering the life-or-death question.}, } @article {pmid33158025, year = {2020}, author = {Lecocq de Pletincx, N and Aron, S}, title = {Sociogenetic Organization of the Red Honey Ant (Melophorus bagoti).}, journal = {Insects}, volume = {11}, number = {11}, pages = {}, pmid = {33158025}, issn = {2075-4450}, support = {J.0151.16 and T.0140.18//Fonds De La Recherche Scientifique - FNRS/ ; }, abstract = {Kin selection and inclusive fitness are thought to be key factors explaining the reproductive altruism displayed by workers in eusocial insect species. However, when a colony's queen has mated with <2 males, workers may increase their fitness by producing their own male offspring. Conversely, when the queen has mated with ≥2 males, workers are expected to increase their inclusive fitness by eschewing the production of their sons and preventing other workers from reproducing as well. Here, we investigated sociogenetic structure and worker reproduction in the red honey ant, Melophorus bagoti. Morphometric analyses revealed that workers belong to one of two distinct subcastes: they are either majors or minors. Using DNA microsatellite markers, we showed that all the colonies had a single, multiple-mated queen and that there was no relationship between worker patriline and worker subcaste. Furthermore, we found that workers were producing males in the presence of the queen, which contrasts with the predictions of inclusive fitness theory. Although our results are based on a small sample, they can serve as the foundation for future research examining worker reproduction in M. bagoti.}, } @article {pmid33144958, year = {2020}, author = {Vitt, S and Hiller, J and Thünken, T}, title = {Intrasexual selection: Kin competition increases male-male territorial aggression in a monogamous cichlid fish.}, journal = {Ecology and evolution}, volume = {10}, number = {20}, pages = {11183-11191}, pmid = {33144958}, issn = {2045-7758}, abstract = {During intrasexual competition, individuals of the same sex compete for access to breeding sites and mating partners, often accompanied by aggressive behavior. Kin selection theory predicts different kin-directed social interactions ranging from cooperation to aggression depending on the context and the resource in question. Kin competition reducing indirect fitness might be avoided by actively expelling relatives from territories and by showing higher aggression against kin. The West-African cichlid Pelvicachromis taeniatus is a monogamous cave breeder with males occupying and defending breeding sites against rivals. This species is capable of kin recognition and shows kin-preference during juvenile shoaling and mate choice. However, subadults of P. taeniatus seem to avoid the proximity of same-sex kin. In the present study, we examined territorial aggression of territory holders against intruding related and unrelated males as well as intruder's behavior. We observed higher aggression among related competitors suggesting that related males are less tolerated as neighbors. Avoidance of intrasexual competition with relatives might increase indirect fitness of males in monogamous species.}, } @article {pmid33139540, year = {2020}, author = {Kay, T and Keller, L and Lehmann, L}, title = {The evolution of altruism and the serial rediscovery of the role of relatedness.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {46}, pages = {28894-28898}, pmid = {33139540}, issn = {1091-6490}, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Cooperative Behavior ; Humans ; Models, Genetic ; Selection, Genetic/genetics ; }, abstract = {The genetic evolution of altruism (i.e., a behavior resulting in a net reduction of the survival and/or reproduction of an actor to benefit a recipient) once perplexed biologists because it seemed paradoxical in a Darwinian world. More than half a century ago, W. D. Hamilton explained that when interacting individuals are genetically related, alleles for altruism can be favored by selection because they are carried by individuals more likely to interact with other individuals carrying the alleles for altruism than random individuals in the population ("kin selection"). In recent decades, a substantial number of supposedly alternative pathways to altruism have been published, leading to controversies surrounding explanations for the evolution of altruism. Here, we systematically review the 200 most impactful papers published on the evolution of altruism and identify 43 evolutionary models in which altruism evolves and where the authors attribute the evolution of altruism to a pathway other than kin selection and/or deny the role of relatedness. An analysis of these models reveals that in every case the life cycle assumptions entail local reproduction and local interactions, thereby leading to interacting individuals being genetically related. Thus, contrary to the authors' claims, Hamilton's relatedness drives the evolution to altruism in their models. The fact that several decades of investigating the evolution to altruism have resulted in the systematic and unwitting rediscovery of the same mechanism is testament to the fundamental importance of positive relatedness between actor and recipient for explaining the evolution of altruism.}, } @article {pmid33114592, year = {2020}, author = {Schausberger, P and Sato, Y}, title = {Kin-Mediated Male Choice and Alternative Reproductive Tactics in Spider Mites.}, journal = {Biology}, volume = {9}, number = {11}, pages = {}, pmid = {33114592}, issn = {2079-7737}, support = {L18534//Japan Society for the Promotion of Science/ ; }, abstract = {Optimal outbreeding and kin selection theories state that the degree of kinship is a fundamental determinant in any mating system. However, the role of kinship in male choice and alternative reproductive tactics (ARTs) is poorly known. We assessed the influence of kinship on male choice and expression of ARTs in two populations of two-spotted spider mites Tetranychus urticae. Male spider mites guard premature females, which is an indicator of mate choice, and may conditionally adopt fighting or sneaking tactics to secure access to females. Males competing with kin or non-kin were offered one kin or non-kin female (experiment 1) and single males were presented a choice of kin and non-kin females (experiment 2). Under kin competition, males of both populations were more prone to guard non-kin than kin females at a 3:1 fighter:sneaker ratio. Under non-kin competition, all males were fighters. Under no-choice, males used novelty as indicator of genetic dissimilarity, serving as absolute decision rule for outbreeding. Under choice, comparative evaluation allowed males to preferentially guard females with higher reproductive potential. Overall, our study suggests that male spider mites can assess kinship of rivals and prospective mates. Kin discrimination allows adaptive, context-specific non-random mating preference and adjustment of ARTs.}, } @article {pmid33078506, year = {2020}, author = {Gardner, A and Hardy, ICW}, title = {Adjustment of sex allocation to co-foundress number and kinship under local mate competition: An inclusive-fitness analysis.}, journal = {Journal of evolutionary biology}, volume = {33}, number = {12}, pages = {1806-1812}, pmid = {33078506}, issn = {1420-9101}, support = {771387/ERC_/European Research Council/International ; }, mesh = {Animals ; Biological Evolution ; Female ; *Inbreeding ; Male ; *Models, Genetic ; Ploidies ; *Sex Ratio ; *Sexual Behavior, Animal ; Wasps/*physiology ; }, abstract = {Hamilton's theory of local mate competition (LMC) describes how competition between male relatives for mating opportunities favours a female-biased parental investment. LMC theory has been extended in many ways to explore a range of genetic and life-history influences on sex allocation strategies, including showing that increasing genetic homogeneity within mating groups should favour greater female bias. However, there has been no quantitative theoretical prediction as to how females should facultatively adjust their sex allocation in response to co-foundress number and kinship. This shortfall has been highlighted recently by the finding that sex ratios produced by sub-social parasitoid wasps in the family Bethylidae are affected by the number of co-foundresses and by whether these are sisters or unrelated females. Here we close this gap in LMC theory by taking an inclusive-fitness approach to derive explicit theoretical predictions for this scenario. We find that, in line with the recent empirical results, females should adopt a more female-biased sex allocation when their co-foundresses are less numerous and are their sisters. Our model appears to predict somewhat more female bias than is observed empirically; we discuss a number of possible model extensions that would improve realism and that would be expected to result in a closer quantitative fit with experimental data.}, } @article {pmid33064592, year = {2020}, author = {Madgwick, PG}, title = {Spite and the Geometry of Negative Relatedness.}, journal = {The American naturalist}, volume = {196}, number = {5}, pages = {E119-E126}, doi = {10.1086/710764}, pmid = {33064592}, issn = {1537-5323}, mesh = {Altruism ; Animals ; Behavior, Animal ; Competitive Behavior ; Cooperative Behavior ; *Genetic Fitness ; Models, Genetic ; Selection, Genetic ; *Social Behavior ; }, abstract = {AbstractSpite is the most surprising prediction of inclusive fitness theory because it suggests that a gene can be favored by natural selection despite causing harm to both the individuals that carry it and those around them. A gene for spite can only be favored because of negative relatedness, which means that the actor that carries the gene is less likely to share the gene for spite with the surrounding recipients than the random expectation. While positive relatedness can be simply reduced to the intuitive concept of kinship, negative relatedness is deeply counterintuitive. Here I clarify that negative relatedness is frequency dependent, and I identify a hidden assumption in its widely used formula. Accordingly, while the well-studied "lighter" side of inclusive fitness (with helping behaviors and positive relatedness) is dominated by traits that are favored under kin selection, I predict that the understudied "darker" side of inclusive fitness (with harming behaviors and negative relatedness) is dominated by traits that are favored under greenbeard/kind selection-and I discuss the existing evidence that tentatively supports this hypothesis.}, } @article {pmid32979124, year = {2020}, author = {Revynthi, AM and van Pol, KE and Janssen, A and Egas, M}, title = {Males cannibalise and females disperse in the predatory mite Phytoseiulus persimilis.}, journal = {Experimental & applied acarology}, volume = {82}, number = {2}, pages = {185-198}, doi = {10.1007/s10493-020-00552-9}, pmid = {32979124}, issn = {1572-9702}, support = {Green Innovation Cluster VP4//European Regional Development Fund/ ; }, mesh = {*Animal Distribution ; Animals ; *Cannibalism ; Female ; Larva ; Male ; Mites/*physiology ; Predatory Behavior ; Sex Factors ; }, abstract = {Cannibalism is a widespread phenomenon in nature, often occurring when food is scarce, for example among predators that have overexploited a local prey population. Instead of cannibalising, predators can disperse, thereby avoiding being cannibalised or cannibalising related conspecifics, which results in inclusive fitness loss. Theory on prey exploitation in ephemeral predator-prey systems predicts that predators may be selected to display prudent predation by dispersing early, thus saving food for their remaining offspring. This is especially advantageous when average relatedness in the local population is high. Less prudent predators refrain from dispersing until all prey are exterminated. These prey exploitation strategies may also have repercussions for cannibalism, especially when it is driven by food shortage. We therefore investigated to what extent adult females and males cannibalise or disperse after prey have been exterminated locally. We used two lines of the haplodiploid predatory mite Phytoseiulus persimilis that were selected for early and late dispersal, respectively. In wind tunnels, we observed the cannibalistic and dispersal behaviour of individual adult predators of these lines on a rose leaf with only conspecific larvae as food. Both selection lines behaved similarly, indicating that selection on dispersal behaviour did not result in correlated effects on cannibalism behaviour. Male predators stayed significantly longer on the leaf and engaged more often in cannibalism than females. The results suggest that there might be gender-specific differences in cannibalistic tendency in relation to dispersal. Future theoretical studies on the evolution of cannibalism and dispersal should take differences between the genders into account.}, } @article {pmid32966826, year = {2021}, author = {Sun, S and Broom, M and Johanis, M and Rychtář, J}, title = {A mathematical model of kin selection in floral displays.}, journal = {Journal of theoretical biology}, volume = {509}, number = {}, pages = {110470}, doi = {10.1016/j.jtbi.2020.110470}, pmid = {32966826}, issn = {1095-8541}, mesh = {*Flowers ; Models, Theoretical ; Plants ; *Pollination ; Seeds ; }, abstract = {Plants can adjust their competitive traits for acquiring resources in response to the relatedness of their neighbours. Recently, it has been found that plants can alter their investment in traits of attracting pollinators based on kin-interaction. We build a mathematical model to study the optimal floral display to attract pollinators in a patch with kin structure. We show that when plants can attract pollinators to a whole patch through the magnet effect, the floral display should increase with the increasing relatedness of the plants in the patch. Our model also indicates that increasing investment into attracting pollinators is a form of altruism, reducing a plant's own seed production but increasing the contribution of other plants to its fitness. We also predict that seed production should increase with increasing relatedness in the patch. Our model provides the explicit conditions when resource allocation to attract pollinators in response to neighbour relatedness can be favoured by kin selection, and a possible mechanism for the plants to deal with the consequent loss of pollinator diversity and abundance.}, } @article {pmid32944998, year = {2020}, author = {Erb, WM and Porter, LM}, title = {Variable infant care contributions in cooperatively breeding groups of wild saddleback tamarins.}, journal = {American journal of primatology}, volume = {82}, number = {12}, pages = {e23190}, doi = {10.1002/ajp.23190}, pmid = {32944998}, issn = {1098-2345}, mesh = {Animals ; Bolivia ; Female ; Male ; *Maternal Behavior ; *Paternal Behavior ; Saguinus/*psychology ; Social Behavior ; }, abstract = {Among non-human primates, alloparental infant care is most extensive in callitrichines, and is thought to be particularly costly for tamarins whose helpers may suffer increased energy expenditure, weight loss, and reduced feeding time and mobility. The costs and benefits of infant care likely vary among group members yet very few wild studies have investigated variable infant care contributions. We studied infant care over an 8-month period in four wild groups of saddleback tamarins in Bolivia to evaluate: (a) what forms of infant care are provided, by whom, and when, (b) how individuals adjust their behavior (activity, vigilance, height) while caring for infants, and (c) whether individuals differ in their infant care contributions. We found that infant carrying, food sharing, and grooming varied among groups, and immigrant males-those who joined the group after infants were conceived-participated less in infant care compared to resident males. Adult tamarins fed less, rested more, and increased vigilance while carrying infants. Although we did not detect changes in overall activity budgets between prepartum and postpartum periods, tamarins spent more time scanning their environments postpartum, potentially reflecting increased predation risk to both carriers and infants during this period. Our study provides the first quantitative data on the timing and amount of infant carrying, grooming, and food transfer contributed by all individuals within and among multiple wild groups, filling a critical knowledge gap about the factors affecting infant care, and highlighting evolutionary hypotheses for cooperative breeding in tamarins.}, } @article {pmid32900316, year = {2020}, author = {Darden, SK and James, R and Cave, JM and Brask, JB and Croft, DP}, title = {Trinidadian guppies use a social heuristic that can support cooperation among non-kin.}, journal = {Proceedings. Biological sciences}, volume = {287}, number = {1934}, pages = {20200487}, pmid = {32900316}, issn = {1471-2954}, mesh = {Animals ; Biological Evolution ; Cooperative Behavior ; Heuristics ; Poecilia/*physiology ; }, abstract = {Cooperation among non-kin is well documented in humans and widespread in non-human animals, but explaining the occurrence of cooperation in the absence of inclusive fitness benefits has proven a significant challenge. Current theoretical explanations converge on a single point: cooperators can prevail when they cluster in social space. However, we know very little about the real-world mechanisms that drive such clustering, particularly in systems where cognitive limitations make it unlikely that mechanisms such as score keeping and reputation are at play. Here, we show that Trinidadian guppies (Poecilia reticulata) use a 'walk away' strategy, a simple social heuristic by which assortment by cooperativeness can come about among mobile agents. Guppies cooperate during predator inspection and we found that when experiencing defection in this context, individuals prefer to move to a new social environment, despite having no prior information about this new social group. Our results provide evidence in non-human animals that individuals use a simple social partner updating strategy in response to defection, supporting theoretical work applying heuristics to understanding the proximate mechanisms underpinning the evolution of cooperation among non-kin.}, } @article {pmid32882324, year = {2020}, author = {Guoth, AW and Chernyshova, AM and Thompson, GJ}, title = {Gene-regulatory context of honey bee worker sterility.}, journal = {Bio Systems}, volume = {198}, number = {}, pages = {104235}, doi = {10.1016/j.biosystems.2020.104235}, pmid = {32882324}, issn = {1872-8324}, mesh = {Animals ; Bees/*genetics/physiology ; Cluster Analysis ; Female ; Gene Expression Profiling/*methods ; *Gene Expression Regulation ; Gene Ontology ; *Gene Regulatory Networks ; Insect Proteins/classification/genetics/metabolism ; Male ; Models, Genetic ; Pheromones/metabolism/physiology ; Reproduction/genetics ; Social Behavior ; }, abstract = {The highly organized societies of the Western honey bee Apis mellifera feature a highly reproductive queen at the center of attention and a large cohort of daughters that suppress their own reproduction to help rear more sisters, some of whom become queens themselves. This reproductive altruism is peculiar because in theory it evolves via indirect selection on genes for altruism that are expressed in the sterile workers but not in the reproductive queens. In this study we attempt to situate lists of genes previously implicated in queenright worker sterility into a broader regulatory framework. To do so we use a model bee brain transcriptional regulatory network as a template to infer how sets of genes responsive to ovary-suppressing queen pheromone are functionally interconnected over the model's topology. We predict that genes jointly involved in the regulation of worker sterility should be tightly networked, relative to genes whose functions are unrelated to each other. We find that sets of mapped genes - ranging in size from 17 to 250 - are well dispersed across the network's substructural scaffolds, suggesting that ovary de-activation involves genes that reside within more than one transcriptional regulatory module. For some sets, however, this dispersion is biased into certain areas of the network's substructure. Our analysis identifies the regions enriched for sterility genes and likewise identifies local hub genes that are presumably critical to subnetwork function. Our work offers a glimpse into the gene regulatory context of honey bee worker sterility and uses this context to identify new candidate gene targets for functional analysis. Finally, to the extent that any sterility-related modules identified here have evolved via selection for worker altruism, we can assume that this selection was indirect and of the type specifically invoked by inclusive fitness theory.}, } @article {pmid32869398, year = {2020}, author = {Giehr, J and Wallner, J and Senninger, L and Ruhland, K and Krüger, T and Heinze, J}, title = {Substantial direct fitness gains of workers in a highly eusocial ant.}, journal = {Molecular ecology}, volume = {29}, number = {19}, pages = {3720-3730}, doi = {10.1111/mec.15586}, pmid = {32869398}, issn = {1365-294X}, mesh = {Animals ; *Ants/genetics ; Behavior, Animal ; Genotype ; Male ; Reproduction/genetics ; Social Behavior ; }, abstract = {Hamilton's theory of inclusive fitness suggests that helpers in animal societies gain fitness indirectly by increasing the reproductive performance of a related beneficiary. Helpers in cooperatively breeding birds, mammals and primitively eusocial wasps may additionally obtain direct fitness through inheriting the nest or mating partner of the former reproductive. Here, we show that also workers of a highly eusocial ant may achieve considerable direct fitness by producing males in both queenless and queenright colonies. We investigated the reproductive success of workers of the ant Temnothorax crassispinus in nature and the laboratory by dissecting workers and determining the origin of males by microsatellite analysis. We show that workers are capable of activating their ovaries and successfully producing their sons independently of the presence of a queen. Genotypes revealed that at least one fifth of the males in natural queenright colonies were not offspring of the queen. Most worker-produced males could be assigned to workers that were unrelated to the queen, suggesting egg-laying by drifting workers.}, } @article {pmid32814071, year = {2020}, author = {Ohtsuki, H and Rueffler, C and Wakano, JY and Parvinen, K and Lehmann, L}, title = {The components of directional and disruptive selection in heterogeneous group-structured populations.}, journal = {Journal of theoretical biology}, volume = {507}, number = {}, pages = {110449}, doi = {10.1016/j.jtbi.2020.110449}, pmid = {32814071}, issn = {1095-8541}, mesh = {Alleles ; Biological Evolution ; Models, Genetic ; Phenotype ; *Reproduction ; *Selection, Genetic ; }, abstract = {We derive how directional and disruptive selection operate on scalar traits in a heterogeneous group-structured population for a general class of models. In particular, we assume that each group in the population can be in one of a finite number of states, where states can affect group size and/or other environmental variables, at a given time. Using up to second-order perturbation expansions of the invasion fitness of a mutant allele, we derive expressions for the directional and disruptive selection coefficients, which are sufficient to classify the singular strategies of adaptive dynamics. These expressions include first- and second-order perturbations of individual fitness (expected number of settled offspring produced by an individual, possibly including self through survival); the first-order perturbation of the stationary distribution of mutants (derived here explicitly for the first time); the first-order perturbation of pairwise relatedness; and reproductive values, pairwise and three-way relatedness, and stationary distribution of mutants, each evaluated under neutrality. We introduce the concept of individual k-fitness (defined as the expected number of settled offspring of an individual for which k-1 randomly chosen neighbors are lineage members) and show its usefulness for calculating relatedness and its perturbation. We then demonstrate that the directional and disruptive selection coefficients can be expressed in terms individual k-fitnesses with k=1,2,3 only. This representation has two important benefits. First, it allows for a significant reduction in the dimensions of the system of equations describing the mutant dynamics that needs to be solved to evaluate explicitly the two selection coefficients. Second, it leads to a biologically meaningful interpretation of their components. As an application of our methodology, we analyze directional and disruptive selection in a lottery model with either hard or soft selection and show that many previous results about selection in group-structured populations can be reproduced as special cases of our model.}, } @article {pmid32781951, year = {2020}, author = {Hitchcock, TJ and Gardner, A}, title = {A gene's-eye view of sexual antagonism.}, journal = {Proceedings. Biological sciences}, volume = {287}, number = {1932}, pages = {20201633}, pmid = {32781951}, issn = {1471-2954}, mesh = {Alleles ; Animals ; Biological Evolution ; Dosage Compensation, Genetic ; Female ; Male ; Reproduction ; *Selection, Genetic ; Sex ; *Sex Characteristics ; X Chromosome ; }, abstract = {Females and males may face different selection pressures. Accordingly, alleles that confer a benefit for one sex often incur a cost for the other. Classic evolutionary theory holds that the X chromosome, whose sex-biased transmission sees it spending more time in females, should value females more than males, whereas autosomes, whose transmission is unbiased, should value both sexes equally. However, recent mathematical and empirical studies indicate that male-beneficial alleles may be more favoured by the X chromosome than by autosomes. Here we develop a gene's-eye-view approach that reconciles the classic view with these recent discordant results, by separating a gene's valuation of female versus male fitness from its ability to induce fitness effects in either sex. We use this framework to generate new comparative predictions for sexually antagonistic evolution in relation to dosage compensation, sex-specific mortality and assortative mating, revealing how molecular mechanisms, ecology and demography drive variation in masculinization versus feminization across the genome.}, } @article {pmid32779763, year = {2020}, author = {Port, M and Hildenbrandt, H and Pen, I and Schülke, O and Ostner, J and Weissing, FJ}, title = {The evolution of social philopatry in female primates.}, journal = {American journal of physical anthropology}, volume = {173}, number = {3}, pages = {397-410}, doi = {10.1002/ajpa.24123}, pmid = {32779763}, issn = {1096-8644}, mesh = {Animals ; Anthropology, Physical ; Female ; Homing Behavior/*physiology ; Male ; *Models, Biological ; Primates/*physiology ; *Social Behavior ; *Social Evolution ; }, abstract = {The transition from solitary life to sociality is considered one of the major transitions in evolution. In primates, this transition is currently not well understood. Traditional verbal models appear insufficient to unravel the complex interplay of environmental and demographic factors involved in the evolution of primate sociality, and recent phylogenetic reconstructions have produced conflicting results. We therefore analyze a theoretical model for the evolution of female social philopatry that sheds new light on the question why most primates live in groups. In individual-based simulations, we study the evolution of dispersal strategies of both resident females and their offspring. The model reveals that social philopatry can evolve through kin selection, even if retention of offspring is costly in terms of within-group resource competition and provides no direct benefits. Our model supports the role of predator avoidance as a selective pressure for group-living in primates, but it also suggests that a second benefit of group-living, communal resource defense, might be required to trigger the evolution of sizable groups. Lastly, our model reveals that seemingly small differences in demographic parameters can have profound effects on primate social evolution.}, } @article {pmid32688434, year = {2020}, author = {De Moor, D and Roos, C and Ostner, J and Schülke, O}, title = {Bonds of bros and brothers: Kinship and social bonding in postdispersal male macaques.}, journal = {Molecular ecology}, volume = {29}, number = {17}, pages = {3346-3360}, doi = {10.1111/mec.15560}, pmid = {32688434}, issn = {1365-294X}, mesh = {Animals ; Female ; Male ; *Macaca ; Microsatellite Repeats ; *Social Behavior ; }, abstract = {Group-living animals often maintain a few very close affiliative relationships-social bonds-that can buffer them against many of the inevitable costs of gregariousness. Kinship plays a central role in the development of such social bonds. The bulk of research on kin biases in sociality has focused on philopatric females, who typically live in deeply kin-structured systems, with matrilineal dominance rank inheritance and life-long familiarity between kin. Closely related males, in contrast, are usually not close in rank or familiar, which offers the opportunity to test the importance of kinship per se in the formation of social bonds. So far, however, kin biases in male social bonding have only been tested in philopatric males, where familiarity remains a confounding factor. Here, we studied bonds between male Assamese macaques, a species in which males disperse from their natal groups and in which male bonds are known to affect fitness. Combining extensive behavioural data on 43 adult males over a 10-year period with DNA microsatellite relatedness analyses, we find that postdispersal males form stronger relationships with the few close kin available in the group than with the average nonkin. However, males form the majority of their bonds with nonkin and may choose nonkin over available close kin to bond with. Our results show that kinship facilitates bond formation, but is not a prerequisite for it, which suggests that strong bonds are not restricted to kin in male mammals and that animals cooperate for both direct and indirect fitness benefits.}, } @article {pmid32674869, year = {2020}, author = {Yamamichi, M and Kyogoku, D and Iritani, R and Kobayashi, K and Takahashi, Y and Tsurui-Sato, K and Yamawo, A and Dobata, S and Tsuji, K and Kondoh, M}, title = {Intraspecific Adaptation Load: A Mechanism for Species Coexistence.}, journal = {Trends in ecology & evolution}, volume = {35}, number = {10}, pages = {897-907}, doi = {10.1016/j.tree.2020.05.011}, pmid = {32674869}, issn = {1872-8383}, mesh = {Acclimatization ; *Adaptation, Physiological/genetics ; *Biological Evolution ; Humans ; Population Dynamics ; Reproduction ; }, abstract = {Evolutionary ecological theory suggests that selection arising from interactions with conspecifics, such as sexual and kin selection, may result in evolution of intraspecific conflicts and evolutionary 'tragedy of the commons'. Here, we propose that such an evolution of conspecific conflicts may affect population dynamics in a way that enhances species coexistence. Empirical evidence and theoretical models suggest that more abundant species is more susceptible to invasion of 'selfish' individuals that increase their own reproductive success at the expense of population growth (intraspecific adaptation load). The density-dependent intraspecific adaptation load gives rise to a self-regulation mechanism at the population level, and stabilizes species coexistence at the community level by negative frequency-dependence.}, } @article {pmid32673089, year = {2020}, author = {Ducouret, P and Romano, A and Dreiss, AN and Marmaroli, P and Falourd, X and Bincteux, M and Roulin, A}, title = {Elder Barn Owl Nestlings Flexibly Redistribute Parental Food according to Siblings' Need or in Return for Allopreening.}, journal = {The American naturalist}, volume = {196}, number = {2}, pages = {257-269}, doi = {10.1086/709106}, pmid = {32673089}, issn = {1537-5323}, mesh = {Animals ; Behavior, Animal ; Competitive Behavior ; Cooperative Behavior ; *Feeding Behavior ; Female ; Grooming ; Male ; Nesting Behavior ; *Siblings ; Strigiformes/*physiology ; Switzerland ; Vocalization, Animal ; }, abstract = {Kin selection and reciprocation of biological services are distinct theories invoked to explain the origin and evolutionary maintenance of altruistic and cooperative behaviors. Although these behaviors are not considered to be mutually exclusive, the cost-benefit balance of behaving altruistically or cooperating reciprocally and the conditions promoting a switch between such different strategies have rarely been tested. Here, we examine the association between allofeeding, allopreening, and vocal solicitations in wild barn owl (Tyto alba) broods under different food abundance conditions: natural food provisioning and after an experimental food supplementation. Allofeeding was performed mainly by elder nestlings (hatching is asynchronous) in prime condition, especially when the cost of forgoing a prey was small (when parents allocated more prey to the food donor and after food supplementation). Nestlings preferentially shared food with the siblings that emitted very intense calls, thus potentially increasing indirect fitness benefits, or with the siblings that provided extensive allopreening to the donor, thus possibly promoting direct benefits from reciprocation. Finally, allopreening was mainly directed toward older siblings, perhaps to maximize the probability of being fed in return. Helping behavior among relatives can therefore be driven by both kin selection and direct cooperation, although it is dependent on the contingent environmental conditions.}, } @article {pmid32665274, year = {2020}, author = {Kogay, R and Wolf, YI and Koonin, EV and Zhaxybayeva, O}, title = {Selection for Reducing Energy Cost of Protein Production Drives the GC Content and Amino Acid Composition Bias in Gene Transfer Agents.}, journal = {mBio}, volume = {11}, number = {4}, pages = {}, pmid = {32665274}, issn = {2150-7511}, mesh = {Alphaproteobacteria/*genetics ; Amino Acids ; Bacterial Proteins/*genetics ; Bacteriophages/genetics ; Base Composition ; *Gene Transfer, Horizontal ; Genes, Viral ; Genome, Bacterial ; Prophages/genetics ; }, abstract = {Gene transfer agents (GTAs) are virus-like elements integrated into bacterial genomes, particularly, those of Alphaproteobacteria The GTAs can be induced under conditions of nutritional stress, incorporate random fragments of bacterial DNA into miniphage particles, lyse the host cells, and infect neighboring bacteria, thus enhancing horizontal gene transfer. We show that GTA genes evolve under conditions of pronounced positive selection for the reduction of the energy cost of protein production as shown by comparison of the amino acid compositions with those of both homologous viral genes and host genes. The energy saving in GTA genes is comparable to or even more pronounced than that in the genes encoding the most abundant, essential bacterial proteins. In cases in which viruses acquire genes from GTAs, the bias in amino acid composition disappears in the course of evolution, showing that reduction of the energy cost of protein production is an important factor of evolution of GTAs but not bacterial viruses. These findings strongly suggest that GTAs represent bacterial adaptations rather than selfish, virus-like elements. Because GTA production kills the host cell and does not propagate the GTA genome, it appears likely that the GTAs are retained in the course of evolution via kin or group selection. Therefore, we hypothesize that GTAs facilitate the survival of bacterial populations under energy-limiting conditions through the spread of metabolic and transport capabilities via horizontal gene transfer and increases in nutrient availability resulting from the altruistic suicide of GTA-producing cells.IMPORTANCE Kin selection and group selection remain controversial topics in evolutionary biology. We argue that these types of selection are likely to operate in bacterial populations by showing that bacterial gene transfer agents (GTAs), but not related viruses, evolve under conditions of positive selection for the reduction of the energy cost of GTA particle production. We hypothesize that GTAs are dedicated devices mediating the survival of bacteria under conditions of nutrient limitation. The benefits conferred by GTAs under nutritional stress conditions appear to include horizontal dissemination of genes that could provide bacteria with enhanced capabilities for nutrient utilization and increases of nutrient availability occurring through the lysis of GTA-producing bacteria.}, } @article {pmid32651398, year = {2020}, author = {O'Corry-Crowe, G and Suydam, R and Quakenbush, L and Smith, TG and Lydersen, C and Kovacs, KM and Orr, J and Harwood, L and Litovka, D and Ferrer, T}, title = {Group structure and kinship in beluga whale societies.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {11462}, pmid = {32651398}, issn = {2045-2322}, abstract = {Evolutionary explanations for mammalian sociality typically center on inclusive-fitness benefits of associating and cooperating with close kin, or close maternal kin as in some whale societies, including killer and sperm whales. Their matrilineal structure has strongly influenced the thinking about social structure in less well-studied cetaceans, including beluga whales. In a cross-sectional study of group structure and kinship we found that belugas formed a limited number of distinct group types, consistently observed across populations and habitats. Certain behaviours were associated with group type, but group membership was often dynamic. MtDNA-microsatellite profiling combined with relatedness and network analysis revealed, contrary to predictions, that most social groupings were not predominantly organized around close maternal relatives. They comprised both kin and non-kin, many group members were paternal rather than maternal relatives, and unrelated adult males often traveled together. The evolutionary mechanisms that shape beluga societies are likely complex; fitness benefits may be achieved through reciprocity, mutualism and kin selection. At the largest scales these societies are communities comprising all ages and both sexes where multiple social learning pathways involving kin and non-kin can foster the emergence of cultures. We explore the implications of these findings for species management and the evolution of menopause.}, } @article {pmid32637404, year = {2020}, author = {Hockings, N and Howard, D}, title = {New Biological Morphogenetic Methods for Evolutionary Design of Robot Bodies.}, journal = {Frontiers in bioengineering and biotechnology}, volume = {8}, number = {}, pages = {621}, pmid = {32637404}, issn = {2296-4185}, abstract = {We present some currently unused morphogenetic mechanisms from evolutionary biology and guidelines for transfer to evolutionary robotics. (1) DNA patterns providing mutation of mutability, lead to canalization of evolvable bauplans, via kin selection. (2) Morphogenetic mechanisms (i) Epigenetic cell lines provide functional cell types, and identification of cell descent. (ii) Local anatomical coordinates based on diffusion of morphogens, facilitate evolvable genetic parameterizations of complex phenotypes (iii) Remodeling in response to mechanical forces facilitates robust production of well-integrated phenotypes of greater complexity than the genome. An approach is proposed for the tractable application of mutation-of-mutability and morphogenetic mechanisms in evolutionary robotics. The purpose of these methods, is to facilitate production of robot mechanisms of the subtlety, efficiency, and efficacy of the musculoskeletal and dermal systems of animals.}, } @article {pmid32627189, year = {2020}, author = {Araya-Ajoy, YG and Westneat, DF and Wright, J}, title = {Pathways to social evolution and their evolutionary feedbacks.}, journal = {Evolution; international journal of organic evolution}, volume = {74}, number = {9}, pages = {1894-1907}, doi = {10.1111/evo.14054}, pmid = {32627189}, issn = {1558-5646}, mesh = {Animals ; *Biological Evolution ; *Phenotype ; *Social Evolution ; }, abstract = {In the context of social evolution, the ecological drivers of selection are the phenotypes of other individuals. The social environment can thus evolve, potentially changing the adaptive value for different social strategies. Different branches of evolutionary biology have traditionally focused on different aspects of these feedbacks. Here, we synthesize behavioral ecology theory concerning evolutionarily stable strategies when fitness is frequency dependent with quantitative genetic models providing statistical descriptions of evolutionary responses to social selection. Using path analyses, we review how social interactions influence the strength of selection and how social responsiveness, social impact, and non-random social assortment affect responses to social selection. We then detail how the frequency-dependent nature of social interactions fits into this framework and how it imposes selection on traits mediating social responsiveness, social impact, and social assortment, further affecting evolutionary dynamics. Throughout, we discuss the parameters in quantitative genetics models of social evolution from a behavioral ecology perspective and identify their statistical counterparts in empirical studies. This integration of behavioral ecology and quantitative genetic perspectives should lead to greater clarity in the generation of hypotheses and more focused empirical research regarding evolutionary pathways and feedbacks inherent in specific social interactions.}, } @article {pmid32614977, year = {2020}, author = {Lee, DS and Mandalaywala, TM and Dubuc, C and Widdig, A and Higham, JP}, title = {Higher early life mortality with lower infant body mass in a free-ranging primate.}, journal = {The Journal of animal ecology}, volume = {89}, number = {10}, pages = {2300-2310}, doi = {10.1111/1365-2656.13291}, pmid = {32614977}, issn = {1365-2656}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Animals ; Female ; Humans ; Macaca mulatta ; *Mothers ; Phenotype ; Puerto Rico ; *Reproduction ; }, abstract = {Traits that reflect the amount of energy allocated to offspring by mothers, such as infant body mass, are predicted to have long-lasting effects on offspring fitness. In very long-lived species, such as anthropoid primates, where long-lasting and obligate parental care is required for successful recruitment of offspring, there are few studies on the fitness implications of low body mass among infants. Using body mass data collected from 253 free-ranging rhesus macaque Macaca mulatta infants on Cayo Santiago, Puerto Rico, we examined if lower infant body mass predicts lower chance of survival through to reproductive maturation (4th year of life). We also used data on inter-birth intervals and suckling behaviours to determine whether the duration of maternal care was adjusted to infant body mass. Rhesus macaque infants experienced on average 5% reduced hazard of death for an increase in body mass of 0.1 SD (~100 g) above the mean within their age-sex class. The positive association between body mass and early life survival was most pronounced in the 1st year of life. Infant body mass tended to be lower if mothers were young or old, but the link between infant body mass and early life survival remained after controlling for maternal age. This finding suggests that maternal effects on early life survival such as maternal age may act through their influence on infant body mass. Mothers of heavier infants were less likely to be delayed in subsequent reproduction, but the estimated association slightly overlapped with zero. The timing of the last week of suckling did not differ by infant body mass. Using infant body mass data that has been rarely available from free-ranging primates, our study provides comparative evidence to strengthen the existing body of literature on the fitness implications of variation in infant body mass.}, } @article {pmid32605521, year = {2020}, author = {Keaney, TA and Wong, HWS and Dowling, DK and Jones, TM and Holman, L}, title = {Sibling rivalry versus mother's curse: can kin competition facilitate a response to selection on male mitochondria?.}, journal = {Proceedings. Biological sciences}, volume = {287}, number = {1930}, pages = {20200575}, pmid = {32605521}, issn = {1471-2954}, mesh = {Animals ; Drosophila melanogaster ; Female ; Haplotypes ; Male ; Maternal Inheritance ; *Mitochondria ; *Selection, Genetic ; Siblings ; }, abstract = {Assuming that fathers never transmit mitochondrial DNA (mtDNA) to their offspring, mitochondrial mutations that affect male fitness are invisible to direct selection on males, leading to an accumulation of male-harming alleles in the mitochondrial genome (mother's curse). However, male phenotypes encoded by mtDNA can still undergo adaptation via kin selection provided that males interact with females carrying related mtDNA, such as their sisters. Here, using experiments with Drosophila melanogaster carrying standardized nuclear DNA but distinct mitochondrial DNA, we test whether the mitochondrial haplotype carried by interacting pairs of larvae affects survival to adulthood, as well as the fitness of the adults. Although mtDNA had no detectable direct or indirect genetic effect on larva-to-adult survival, the fitness of male and female adults was significantly affected by their own mtDNA and the mtDNA carried by their social partner in the larval stage. Thus, mtDNA mutations that alter the effect of male larvae on nearby female larvae (which often carry the same mutation, due to kinship) could theoretically respond to kin selection. We discuss the implications of our findings for the evolution of mitochondria and other maternally inherited endosymbionts.}, } @article {pmid32581916, year = {2020}, author = {Gyuris, P and Kozma, L and Kisander, Z and Láng, A and Ferencz, T and Kocsor, F}, title = {Sibling Relations in Patchwork Families: Co-residence Is More Influential Than Genetic Relatedness.}, journal = {Frontiers in psychology}, volume = {11}, number = {}, pages = {993}, pmid = {32581916}, issn = {1664-1078}, abstract = {In "patchwork" families, full siblings, maternal and paternal half-siblings, and non-related children are raised together, and sometimes, genetically related children are separated. As their number is steadily growing, the investigation of the factors that influence within-family relations is becoming more important. Our aim was to explore whether people differentiate between half- and full-siblings in their social relations as implied by the theory of inclusive fitness, and to test whether co-residence or genetic relatedness improves sibling relations to a larger extent. We administered the Sibling Relationship Questionnaire to 196 individuals who were in contact with full-, half-, or step-siblings in their childhood. We built Generalized Linear Mixed Models models to test for the effects of relatedness and co-residence on sibling relations. In general, a higher degree of relatedness was associated with better sibling relations, but only among those who did not live together during childhood. Co-resident siblings' overall pattern of relation quality was not influenced by the actual level of genetic relatedness. In contrast to this, full siblings reported having experienced more conflicts during childhood than half-siblings, possibly resulting from enhanced competition for the same parental resources. The results suggest that inclusive fitness drives siblings' relations even in recent industrial societies. However, among individuals who live together, the effect of relatedness might be obscured by fitness interdependence and the subjective feeling of kinship.}, } @article {pmid32537201, year = {2020}, author = {Pang, TY}, title = {On age-specific selection and extensive lifespan beyond menopause.}, journal = {Royal Society open science}, volume = {7}, number = {5}, pages = {191972}, pmid = {32537201}, issn = {2054-5703}, abstract = {Standard evolutionary theory of ageing predicts weaker purifying selection on genes critical to later life stages. Prolonged post-reproductive lifespan (PPRLS), observed only in a few species like humans, is likely a result of disparate relaxation of purifying selection on survival and reproduction in late life stages. While the exact origin of PPRLS is under debate, many researchers agree on hypotheses like mother-care and grandmother-care, which ascribe PPRLS to investment into future generations-provision to one's descendants to enhance their overall reproductive success. Here, we simulate an agent-based model, which properly accounts for age-specific selection, to examine how different investment strategies affect the strength of purifying selection on survival and reproduction. We observed in the simulations that investment strategies that allow a female individual to remain contributive to its own descendants (infants and adults) at late life stages may lead to differential relaxation of selection on survival and reproduction, and incur the adaptive evolution of PPRLS.}, } @article {pmid32502408, year = {2020}, author = {Granato, ET and Foster, KR}, title = {The Evolution of Mass Cell Suicide in Bacterial Warfare.}, journal = {Current biology : CB}, volume = {30}, number = {14}, pages = {2836-2843.e3}, pmid = {32502408}, issn = {1879-0445}, support = {/WT_/Wellcome Trust/United Kingdom ; 209397/Z/17/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Bacterial Toxins/*metabolism/*toxicity ; *Biological Evolution ; Cell Death/*drug effects ; Colicins/*metabolism/*toxicity ; Escherichia coli/drug effects/*metabolism/pathogenicity/*physiology ; }, abstract = {Behaviors that cause the death of an actor are typically strongly disfavored by natural selection, and yet many bacteria undergo cell lysis to release anti-competitor toxins [1-5]. This behavior is most easily explained if only a small proportion of cells die to release toxins and help their clonemates, but the frequency of cells that actually lyse during bacterial warfare is unknown. The challenge is finding a way to distinguish cells that have undergone programmed suicide from those that were simply killed by a competitor's toxin. We developed a two-color fluorescence reporter assay in Escherichia coli to overcome this problem. This revealed conditions where nearly all cells undergo programmed lysis. Specifically, adding a DNA-damaging toxin (DNase colicin) from another strain induced mass cell suicide where ∼85% of cells lysed to release their own toxins. Time-lapse 3D confocal microscopy showed that self-lysis occurs locally at even higher frequencies (∼94%) at the interface between toxin-producing colonies. By exposing E. coli that do not perform lysis to the DNase colicin, we found that mass lysis occurs when cells are going to die anyway from toxin exposure. From an evolutionary perspective, this renders the behavior cost-free as these cells have zero reproductive potential. This helps to explain how mass cell suicide can evolve, as any small benefit to surviving clonemates can lead to this retaliatory strategy being favored by natural selection. Our findings have parallels to the suicidal attacks of social insects [6-9], which are also performed by individuals with low reproductive potential.}, } @article {pmid32469661, year = {2020}, author = {Downing, PA and Griffin, AS and Cornwallis, CK}, title = {The Benefits of Help in Cooperative Birds: Nonexistent or Difficult to Detect?.}, journal = {The American naturalist}, volume = {195}, number = {6}, pages = {1085-1091}, doi = {10.1086/708515}, pmid = {32469661}, issn = {1537-5323}, mesh = {Animals ; Behavior, Animal ; *Cooperative Behavior ; Nesting Behavior/physiology ; Passeriformes/*physiology ; Reproduction/*physiology ; }, abstract = {In birds that breed cooperatively in family groups, adult offspring often delay dispersal to assist the breeding pair in raising their young. Kin selection is thought to play an important role in the evolution of this breeding system. However, evidence supporting the underlying assumption that helpers increase the reproductive success of breeders is inconsistent. In 10 out of 19 species where the effect of helpers on breeder reproductive success has been estimated while controlling for the effects of breeder and territory quality, no benefits of help were detected. Here, we use phylogenetic meta-analysis to show that the inconsistent evidence for helper benefits across species is explained by study design. After accounting for low sample sizes and the different study designs used to control for breeder and territory quality, we found that helpers consistently enhanced the reproductive success of breeders. Therefore, the assumption that helpers increase breeder reproductive success is supported by evidence across cooperatively breeding birds.}, } @article {pmid32451427, year = {2020}, author = {Faria, GS and Gardner, A and Carazo, P}, title = {Kin discrimination and demography modulate patterns of sexual conflict.}, journal = {Nature ecology & evolution}, volume = {4}, number = {8}, pages = {1141-1148}, pmid = {32451427}, issn = {2397-334X}, support = {771387/ERC_/European Research Council/International ; }, mesh = {Animals ; Demography ; Male ; *Models, Theoretical ; *Sexual Behavior, Animal ; }, abstract = {Recent years have seen an explosion of interest in the overlap between kin selection and sexual selection, particularly concerning how kin selection can put the brakes on harmful sexual conflict. However, there remains a significant disconnect between theory and empirical research. Whilst empirical work has focused on kin-discriminating behaviour, theoretical models have assumed indiscriminating behaviour. Additionally, theoretical work makes particular demographic assumptions that constrain the relationship between genetic relatedness and the scale of competition, and it is not clear that these assumptions reflect the natural setting in which sexual conflict has been empirically studied. Here, we plug this gap between current theoretical and empirical understanding by developing a mathematical model of sexual conflict that incorporates kin discrimination and different patterns of dispersal. We find that kin discrimination and group dispersal inhibit harmful male behaviours at an individual level, but kin discrimination intensifies sexual conflict at the population level.}, } @article {pmid32445518, year = {2021}, author = {Timming, AR and French, MT}, title = {The effect of genetic vs nongenetic parental care on adult children's income and wealth in later life: An evolutionary analysis.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {33}, number = {1}, pages = {e23431}, doi = {10.1002/ajhb.23431}, pmid = {32445518}, issn = {1520-6300}, mesh = {Adult ; Adult Children/*statistics & numerical data ; *Biological Evolution ; Female ; Humans ; Income/*statistics & numerical data ; Longitudinal Studies ; Male ; *Maternal Behavior ; *Parents ; *Paternal Behavior ; United States ; Young Adult ; }, abstract = {OBJECTIVE: Using Wave IV of the National Longitudinal Study of Adolescent to Adult Health data set, this preregistered study set out to investigate the effect of parental care arrangements (eg, genetically related parents, adoptive, step/ foster, genetic nonparental relative, and no parental figure) on adult children's income and wealth in later life.

METHODS: Consistent with the preregistration plan, multivariate analyses of covariance were first used to examine, separately, the effects of paternal and maternal care arrangements on children's income and wealth in later life. Further post hoc exploratory analyses were carried out to evaluate the robustness of the findings.

RESULTS: The results indicate that individual earnings in later life are unrelated to paternal care arrangements, thus questioning a key tenet of kin selection theory. However, children raised by biological fathers and adoptive fathers still enjoy significant economic advantages over nongenetic father figures and homes without fathers in relation to household income and wealth.

CONCLUSIONS: Prevailing theories suggest that children raised by relatives, nongenetically related parents, and no father or mother suffer from a lack of parental investment that should manifest itself in reduced earnings and assets in adulthood. These theories are only partially correct, with evidence pointing to no deleterious effect of variable parental arrangements on individual earnings.}, } @article {pmid32440290, year = {2020}, author = {Termignoni-Garcia, F and Louder, MIM and Balakrishnan, CN and O'Connell, L and Edwards, SV}, title = {Prospects for sociogenomics in avian cooperative breeding and parental care.}, journal = {Current zoology}, volume = {66}, number = {3}, pages = {293-306}, pmid = {32440290}, issn = {1674-5507}, abstract = {For the last 40 years, the study of cooperative breeding (CB) in birds has proceeded primarily in the context of discovering the ecological, geographical, and behavioral drivers of helping. The advent of molecular tools in the early 1990s assisted in clarifying the relatedness of helpers to those helped, in some cases, confirming predictions of kin selection theory. Methods for genome-wide analysis of sequence variation, gene expression, and epigenetics promise to add new dimensions to our understanding of avian CB, primarily in the area of molecular and developmental correlates of delayed breeding and dispersal, as well as the ontogeny of achieving parental status in nature. Here, we outline key ways in which modern -omics approaches, in particular genome sequencing, transcriptomics, and epigenetic profiling such as ATAC-seq, can be used to add a new level of analysis of avian CB. Building on recent and ongoing studies of avian social behavior and sociogenomics, we review how high-throughput sequencing of a focal species or clade can provide a robust foundation for downstream, context-dependent destructive and non-destructive sampling of specific tissues or physiological states in the field for analysis of gene expression and epigenetics. -Omics approaches have the potential to inform not only studies of the diversification of CB over evolutionary time, but real-time analyses of behavioral interactions in the field or lab. Sociogenomics of birds represents a new branch in the network of methods used to study CB, and can help clarify ways in which the different levels of analysis of CB ultimately interact in novel and unexpected ways.}, } @article {pmid32402118, year = {2020}, author = {Sapp, JR and Yost, J and Lyon, BE}, title = {The socially parasitic ant Polyergus mexicanus has host-associated genetic population structure and related neighbouring colonies.}, journal = {Molecular ecology}, volume = {29}, number = {11}, pages = {2050-2062}, doi = {10.1111/mec.15468}, pmid = {32402118}, issn = {1365-294X}, mesh = {Animals ; *Ants/genetics ; *Genetics, Population ; Host-Parasite Interactions/genetics ; Microsatellite Repeats ; *Parasites/genetics ; }, abstract = {The genetic structure of populations can be both a cause and a consequence of ecological interactions. For parasites, genetic structure may be a consequence of preferences for host species or of mating behaviour. Conversely, genetic structure can influence where conspecific interactions among parasites lay on a spectrum from cooperation to conflict. We used microsatellite loci to characterize the genetic structure of a population of the socially parasitic dulotic (aka "slave-making") ant (Polyergus mexicanus), which is known for its host-specificity and conspecific aggression. First, we assessed whether the pattern of host species use by the parasite has influenced parasite population structure. We found that host species use was correlated with subpopulation structure, but this correlation was imperfect: some subpopulations used one host species nearly exclusively, while others used several. Second, we examined the viscosity of the parasite population by measuring the relatedness of pairs of neighbouring parasitic ant colonies at varying distances from each other. Although natural history observations of local dispersal by queens suggested the potential for viscosity, there was no strong correlation between relatedness and distance between colonies. However, 35% of colonies had a closely related neighbouring colony, indicating that kinship could potentially affect the nature of some interactions between colonies of this social parasite. Our findings confirm that ecological forces like host species selection can shape the genetic structure of parasite populations, and that such genetic structure has the potential to influence parasite-parasite interactions in social parasites via inclusive fitness.}, } @article {pmid32398794, year = {2020}, author = {Schausberger, P and Çekin, D}, title = {Plastic female choice to optimally balance (k)in- and out-breeding in a predatory mite.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {7861}, pmid = {32398794}, issn = {2045-2322}, mesh = {Acrylates ; Animals ; Breeding ; Female ; Greece ; Inbreeding ; Male ; Mites/classification/*physiology ; Plastics ; Predatory Behavior/physiology ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; Sicily ; *Social Behavior ; }, abstract = {Both close inbreeding and extreme outbreeding may negatively affect direct fitness. Optimal outbreeding theory suggests that females should preferentially mate with distantly related males. (K)in breeding theory suggests that, at similar direct fitness costs of close inbreeding and extreme outbreeding, females should prefer close kin to non-kin. Empirical evidence of plastic female choice for an optimal balance between close inbreeding and extreme outbreeding remains elusive. We tested the combined predictions of optimal outbreeding and (k)in breeding theories in predatory mites Phytoseiulus persimilis from two origins, Sicily and Greece, which suffer from both close inbreeding and extreme outbreeding depression. In three separate experiments, virgin females were presented binary choices between familiar and unfamiliar brothers, and between familiar/unfamiliar brothers and distant kin or non-kin. Females of Greece but not Sicily preferred unfamiliar to familiar brothers. Females of both origins preferred distant kin to unfamiliar and familiar brothers but preferred unfamiliar brothers to non-kin. Females of Sicily but not Greece preferred familiar brothers to non-kin. The suggested kin recognition mechanisms are phenotype matching and direct familiarity, with finer-tuned recognition abilities of Greece females. Overall, our experiments suggest that flexible mate choice by P. persimilis females allows optimally balancing inclusive fitness trade-offs.}, } @article {pmid32369588, year = {2020}, author = {Bhattacharjee, S and Mishra, AK}, title = {The tale of caspase homologues and their evolutionary outlook: deciphering programmed cell death in cyanobacteria.}, journal = {Journal of experimental botany}, volume = {71}, number = {16}, pages = {4639-4657}, pmid = {32369588}, issn = {1460-2431}, mesh = {*Apoptosis ; Biological Evolution ; Caspases/genetics/metabolism ; *Cyanobacteria/genetics/metabolism ; Proteolysis ; }, abstract = {Programmed cell death (PCD), a genetically orchestrated mechanism of cellular demise, is paradoxically required to support life. As in lower eukaryotes and bacteria, PCD in cyanobacteria is poorly appreciated, despite recent biochemical and molecular evidence that supports its existence. Cyanobacterial PCD is an altruistic reaction to stressful conditions that significantly enhances genetic diversity and inclusive fitness of the population. Recent bioinformatic analysis has revealed an abundance of death-related proteases, i.e. orthocaspases (OCAs) and their mutated variants, in cyanobacteria, with the larger genomes of morphologically complex strains harbouring most of them. Sequence analysis has depicted crucial accessory domains along with the proteolytic p20-like sub-domain in OCAs, predicting their functional versatility. However, the cascades involved in sensing death signals, their transduction, and the downstream expression and activation of OCAs remain to be elucidated. Here, we provide a comprehensive description of the attempts to identify mechanisms of PCD and the existence and importance of OCAs based on in silico approaches. We also review the evolutionary and ecological significance of PCD in cyanobacteria. In the future, the analysis of cyanobacterial PCD will identify novel proteins that have varied functional roles in signalling cascades and also help in understanding the incipient mechanism of PCD morphotype(s) from where eukaryotic PCD might have originated.}, } @article {pmid32364789, year = {2020}, author = {Thünken, T and Hesse, S and Meuthen, D}, title = {Increased Levels of Perceived Competition Decrease Juvenile Kin-Shoaling Preferences in a Cichlid Fish.}, journal = {The American naturalist}, volume = {195}, number = {5}, pages = {868-875}, doi = {10.1086/707747}, pmid = {32364789}, issn = {1537-5323}, mesh = {Animals ; Cichlids/*physiology ; Competitive Behavior ; Food Deprivation ; Genetic Fitness ; Siblings ; *Social Behavior ; }, abstract = {Inclusive fitness theory predicts that individuals can increase their indirect fitness by grouping with kin. However, kin grouping also increases competition between kin, which potentially outweighs its benefits. The level of kin competition is contingent on environmental conditions and thus highly variable. Hence, individuals should benefit from plastically adjusting kin discrimination according to the expected level of kin competition. Here, we investigate whether perceived high competition affects juvenile kin-shoaling preferences in the cichlid Pelvicachromis taeniatus. Juveniles were given the choice between two shoals consisting of either kin or nonkin. Levels of perceived competition were manipulated through food limitation in the face of the differential energy expenditure of differently sized fish. The preference to shoal with kin decreased with increasing levels of perceived competition; small food-deprived individuals avoided kin. Shoaling with kin under strong competition may reduce individual indirect fitness. Hence, individuals can likely improve their inclusive fitness by plastically adjusting their kin-grouping preferences.}, } @article {pmid32332728, year = {2020}, author = {Makarenko, R and Denis, C and Francesconi, S and Gangloff, S and Arcangioli, B}, title = {Nitrogen starvation reveals the mitotic potential of mutants in the S/MAPK pathways.}, journal = {Nature communications}, volume = {11}, number = {1}, pages = {1973}, pmid = {32332728}, issn = {2041-1723}, mesh = {Coculture Techniques ; DNA/metabolism ; Flow Cytometry ; Genetic Variation ; Genotype ; *MAP Kinase Signaling System ; *Mitosis ; *Mutation ; Nitrogen/*physiology ; Phenotype ; Protein Serine-Threonine Kinases/genetics ; Saccharomyces cerevisiae/genetics/physiology ; Schizosaccharomyces/*genetics/*physiology ; Schizosaccharomyces pombe Proteins/genetics ; Sequence Analysis, DNA ; Signal Transduction ; Stochastic Processes ; }, abstract = {The genetics of quiescence is an emerging field compared to that of growth, yet both states generate spontaneous mutations and genetic diversity fueling evolution. Reconciling mutation rates in dividing conditions and mutation accumulation as a function of time in non-dividing situations remains a challenge. Nitrogen-starved fission yeast cells reversibly arrest proliferation, are metabolically active and highly resistant to a variety of stresses. Here, we show that mutations in stress- and mitogen-activated protein kinase (S/MAPK) signaling pathways are enriched in aging cultures. Targeted resequencing and competition experiments indicate that these mutants arise in the first month of quiescence and expand clonally during the second month at the expense of the parental population. Reconstitution experiments show that S/MAPK modules mediate the sacrifice of many cells for the benefit of some mutants. These findings suggest that non-dividing conditions promote genetic diversity to generate a social cellular environment prone to kin selection.}, } @article {pmid37588364, year = {2020}, author = {van Veelen, M}, title = {The group selection-inclusive fitness equivalence claim: not true and not relevant.}, journal = {Evolutionary human sciences}, volume = {2}, number = {}, pages = {e11}, pmid = {37588364}, issn = {2513-843X}, abstract = {The debate on (cultural) group selection regularly suffers from an inclusive fitness overdose. The classical view is that all group selection is kin selection, and that Hamilton's rule works for all models. I claim that not all group selection is kin selection, and that Hamilton's rule does not always get the direction of selection right. More importantly, I will argue that the paper by Smith (2020; Cultural group selection and human cooperation: a conceptual and empirical review. Evolutionary Human Sciences, 2) shows that inclusive fitness is not particularly relevant for much of the empirical evidence relating to the question whether or not cultural group selection shaped human behaviour.}, } @article {pmid32313691, year = {2020}, author = {Madgwick, PG and Wolf, JB}, title = {Evolution of strategic cooperation.}, journal = {Evolution letters}, volume = {4}, number = {2}, pages = {164-175}, pmid = {32313691}, issn = {2056-3744}, abstract = {Group-beneficial behaviors have presented a long-standing challenge for evolutionary theory because, although their benefits are available to all group members, their costs are borne by individuals. Consequently, an individual could benefit from "cheating" their group mates by not paying the costs while still reaping the benefits. There have been many proposed evolutionary mechanisms that could favor cooperation (and disfavor cheating) in particular circumstances. However, if cooperation is still favored in some circumstances, then we might expect evolution to favor strategic cooperation, where the level of contribution toward group-beneficial behavior is varied in response to the social context. To uncover how and why individuals should contribute toward group-beneficial behavior across social contexts, we model strategic cooperation as an evolutionary game where players can quantitatively adjust the amount they contribute toward group-beneficial behavior. We find that the evolutionarily stable strategy (ESS) predicts, unsurprisingly, that players should contribute in relation to their relatedness to the group. However, we surprisingly find that players often contribute to cooperation in such a way that their fitness is inverse to their relatedness to the group such that those that contribute to cooperation end up with the same return from group-beneficial behavior, essentially removing any potential advantage of higher relatedness. These results bring to light a paradox of group-beneficial cooperation: groups do best when they contain highly related individuals, but those with the highest relatedness to the group will often have the lowest fitness within the group.}, } @article {pmid32301222, year = {2020}, author = {Galimov, ER and Gems, D}, title = {Shorter life and reduced fecundity can increase colony fitness in virtual Caenorhabditis elegans.}, journal = {Aging cell}, volume = {19}, number = {5}, pages = {e13141}, pmid = {32301222}, issn = {1474-9726}, support = {BB/R01356X/1//BBSRC equipment grant/International ; 098565/Z/12/Z//Wellcome Trust Strategic Award/International ; }, mesh = {Animals ; Caenorhabditis elegans/*genetics ; Cellular Senescence/*genetics ; Fertility/*genetics ; Longevity/*genetics ; }, abstract = {In the nematode Caenorhabditis elegans, loss of function of many genes leads to increases in lifespan, sometimes of a very large magnitude. Could this reflect the occurrence of programmed death that, like apoptosis of cells, promotes fitness? The notion that programmed death evolves as a mechanism to remove worn out, old individuals in order to increase food availability for kin is not supported by classic evolutionary theory for most species. However, it may apply in organisms with colonies of closely related individuals such as C. elegans in which largely clonal populations subsist on spatially limited food patches. Here, we ask whether food competition between nonreproductive adults and their clonal progeny could favor programmed death by using an in silico model of C. elegans. Colony fitness was estimated as yield of dauer larva propagules from a limited food patch. Simulations showed that not only shorter lifespan but also shorter reproductive span and reduced adult feeding rate can increase colony fitness, potentially by reducing futile food consumption. Early adult death was particularly beneficial when adult food consumption rate was high. These results imply that programmed, adaptive death could promote colony fitness in C. elegans through a consumer sacrifice mechanism. Thus, C. elegans lifespan may be limited not by aging in the usual sense but rather by apoptosis-like programmed death.}, } @article {pmid32279381, year = {2020}, author = {Lymbery, SJ and Wyber, B and Tomkins, JL and Simmons, LW}, title = {No evidence for divergence in male harmfulness or female resistance in response to changes in the opportunity for dispersal.}, journal = {Journal of evolutionary biology}, volume = {33}, number = {7}, pages = {966-978}, doi = {10.1111/jeb.13628}, pmid = {32279381}, issn = {1420-9101}, mesh = {*Animal Distribution ; Animals ; *Biological Evolution ; *Coleoptera ; Female ; Male ; Models, Genetic ; Selection, Genetic ; *Sexual Behavior, Animal ; }, abstract = {The outcome of sexual conflict can depend on the social environment, as males respond to changes in the inclusive fitness payoffs of harmfulness and harm females less when they compete with familiar relatives. Theoretical models also predict that if limited male dispersal predictably enhances local relatedness while maintaining global competition, kin selection can produce evolutionary divergences in male harmfulness among populations. Experimental tests of these predictions, however, are rare. We assessed rates of dispersal in female and male seed beetles Callosobruchus maculatus, a model species for studies of sexual conflict, in an experimental setting. Females dispersed significantly more often than males, but dispersing males travelled just as far as dispersing females. Next, we used experimental evolution to test whether limiting dispersal allowed the action of kin selection to affect divergence in male harmfulness and female resistance. Populations of C. maculatus were evolved for 20 and 25 generations under one of three dispersal regimens: completely free dispersal, limited dispersal and no dispersal. There was no divergence among treatments in female reproductive tract scarring, ejaculate size, mating behaviour, fitness of experimental females mated to stock males or fitness of stock females mated to experimental males. We suggest that this is likely due to insufficient strength of kin selection rather than a lack of genetic variation or time for selection. Limited dispersal alone is therefore not sufficient for kin selection to reduce male harmfulness in this species, consistent with general predictions that limited dispersal will only allow kin selection if local relatedness is independent of the intensity of competition among kin.}, } @article {pmid32220095, year = {2020}, author = {Smith, NMA and Yagound, B and Remnant, EJ and Foster, CSP and Buchmann, G and Allsopp, MH and Kent, CF and Zayed, A and Rose, SA and Lo, K and Ashe, A and Harpur, BA and Beekman, M and Oldroyd, BP}, title = {Paternally-biased gene expression follows kin-selected predictions in female honey bee embryos.}, journal = {Molecular ecology}, volume = {29}, number = {8}, pages = {1523-1533}, doi = {10.1111/mec.15419}, pmid = {32220095}, issn = {1365-294X}, mesh = {Alleles ; Animals ; Bees/genetics ; Female ; Gene Expression ; *Genomic Imprinting ; Male ; Phenotype ; *Reproduction ; }, abstract = {The Kinship Theory of Genomic Imprinting (KTGI) posits that, in species where females mate with multiple males, there is selection for a male to enhance the reproductive success of his offspring at the expense of other males and his mating partner. Reciprocal crosses between honey bee subspecies show parent-of-origin effects for reproductive traits, suggesting that males modify the expression of genes related to female function in their female offspring. This effect is likely to be greater in the Cape honey bee (Apis mellifera capensis), because a male's daughters have the unique ability to produce female offspring that can develop into reproductive workers or the next queen without mating. We generated reciprocal crosses between Capensis and another subspecies and used RNA-seq to identify transcripts that are over- or underexpressed in the embryos, depending on the parental origin of the gene. As predicted, 21 genes showed expression bias towards the Capensis father's allele in colonies with a Capensis father, with no such bias in the reciprocal cross. A further six genes showed a consistent bias towards expression of the father's allele across all eight colonies examined, regardless of the direction of the cross. Consistent with predictions of the KTGI, six of the 21 genes are associated with female reproduction. No gene consistently showed overexpression of the maternal allele.}, } @article {pmid32216664, year = {2020}, author = {Lehmann, L and Rousset, F}, title = {When Do Individuals Maximize Their Inclusive Fitness?.}, journal = {The American naturalist}, volume = {195}, number = {4}, pages = {717-732}, doi = {10.1086/707561}, pmid = {32216664}, issn = {1537-5323}, mesh = {Adaptation, Biological/*genetics ; Biological Evolution ; *Genetic Fitness ; Genetics, Population ; *Models, Genetic ; Selection, Genetic ; }, abstract = {Adaptation is often described in behavioral ecology as individuals maximizing their inclusive fitness. Under what conditions does this hold, and how does this relate to the gene-centered perspective of adaptation? We unify and extend the literature on these questions to class-structured populations. We demonstrate that the maximization (in the best-response sense) of class-specific inclusive fitness obtains in uninvadable population states (meaning that all deviating mutants become extinct). This defines a genuine actor-centered perspective on adaptation. But this inclusive fitness is assigned to all bearers of a mutant allele in a given class and depends on distributions of demographic and genetic contexts. These distributions, in turn, usually depend on events in previous generations and are thus not under individual control. This prevents, in general, envisioning individuals themselves as autonomous fitness maximizers, each with its own inclusive fitness. For weak selection, however, the dependence on earlier events can be neglected. We then show that each individual in each class appears to maximize its own inclusive fitness when all other individuals exhibit inclusive fitness-maximizing behavior. This defines a genuine individual-centered perspective of adaptation and justifies formally, as a first-order approximation, the long-heralded view of individuals appearing to maximize their own inclusive fitness.}, } @article {pmid32210525, year = {2020}, author = {Gerber, L and Connor, RC and King, SL and Allen, SJ and Wittwer, S and Bizzozzero, MR and Friedman, WR and Kalberer, S and Sherwin, WB and Wild, S and Willems, EP and Krützen, M}, title = {Affiliation history and age similarity predict alliance formation in adult male bottlenose dolphins.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {31}, number = {2}, pages = {361-370}, pmid = {32210525}, issn = {1045-2249}, abstract = {Male alliances are an intriguing phenomenon in the context of reproduction since, in most taxa, males compete over an indivisible resource, female fertilization. Adult male bottlenose dolphins (Tursiops aduncus) in Shark Bay, Western Australia, form long-term, multilevel alliances to sequester estrus females. These alliances are therefore critical to male reproductive success. Yet, the long-term processes leading to the formation of such complex social bonds are still poorly understood. To identify the criteria by which male dolphins form social bonds with other males, we adopted a long-term approach by investigating the ontogeny of alliance formation. We followed the individual careers of 59 males for 14 years while they transitioned from adolescence (8-14 years of age) to adulthood (15-21 years old). Analyzing their genetic relationships and social associations in both age groups, we found that the vast majority of social bonds present in adolescence persisted through time. Male associations in early life predict alliance partners as adults. Kinship patterns explained associations during adolescence but not during adulthood. Instead, adult males associated with males of similar age. Our findings suggest that social bonds among peers, rather than kinship, play a central role in the development of adult male polyadic cooperation in dolphins.}, } @article {pmid32203476, year = {2020}, author = {Daniel, MJ and Williamson, RJ}, title = {Males optimally balance selfish and kin-selected strategies of sexual competition in the guppy.}, journal = {Nature ecology & evolution}, volume = {4}, number = {5}, pages = {745-752}, pmid = {32203476}, issn = {2397-334X}, mesh = {Animals ; Female ; Male ; *Poecilia ; Reproduction ; Sexual Behavior, Animal ; }, abstract = {Resolving the strategies by which organisms compete for limited resources is key to understanding behavioural and social evolution. When competing for matings, males in many species allocate mating effort preferentially towards higher-quality females. How males balance this against avoiding competition with rival males, who should also prefer high-quality females, is poorly understood. Kin selection theory further complicates these dynamics: males should avoid competition with close relatives especially because of added, indirect fitness costs. However, whether between-male relatedness modulates the intensity of intrasexual competition is equivocal. Here, we develop and test an analytical model describing how males should optimally allocate their mating efforts in response to information about differences in female quality, competitor presence/absence and competitor relatedness. Using freely interacting groups of Trinidadian guppies (Poecilia reticulata), we show concordance between observed and predicted mating effort allocation across all combinations of these factors. Thus, male mating effort is sensitive to variation in female quality, competitor presence and competitor relatedness, which is consistent with a kin-selected strategy of male-male competition. The fit of our model's predictions demonstrates that males integrate assessments of female quality and competitive context in a quantitatively meaningful way, implicating a competitive strategy that has been fine-tuned to maximize inclusive fitness gains.}, } @article {pmid32183635, year = {2020}, author = {Faria, GS and Gardner, A}, title = {Does kin discrimination promote cooperation?.}, journal = {Biology letters}, volume = {16}, number = {3}, pages = {20190742}, pmid = {32183635}, issn = {1744-957X}, mesh = {Altruism ; *Biological Evolution ; Humans ; *Social Behavior ; }, abstract = {Genetic relatedness is a key driver of the evolution of cooperation. One mechanism that may ensure social partners are genetically related is kin discrimination, in which individuals are able to distinguish kin from non-kin and adjust their behaviour accordingly. However, the impact of kin discrimination upon the overall level of cooperation remains obscure. Specifically, while kin discrimination allows an individual to help more-related social partners over less-related social partners, it is unclear whether and how the population average level of cooperation that is evolutionarily favoured should differ under kin discrimination versus indiscriminate social behaviour. Here, we perform a general mathematical analysis in order to assess whether, when and in which direction kin discrimination changes the average level of cooperation in an evolving population. We find that kin discrimination may increase, decrease or leave unchanged the average level of cooperation, depending upon whether the optimal level of cooperation is a convex, concave or linear function of genetic relatedness. We develop an extension of the classic 'tragedy of the commons' model of cooperation in order to provide an illustration of these results. Our analysis provides a method to guide future research on the evolutionary consequences of kin discrimination.}, } @article {pmid32183634, year = {2020}, author = {Kennedy, P and Radford, AN}, title = {Sibling quality and the haplodiploidy hypothesis.}, journal = {Biology letters}, volume = {16}, number = {3}, pages = {20190764}, pmid = {32183634}, issn = {1744-957X}, mesh = {Animals ; Bees ; *Biological Evolution ; Female ; Humans ; Male ; Models, Biological ; Sex Ratio ; *Siblings ; Social Behavior ; }, abstract = {The 'haplodiploidy hypothesis' argues that haplodiploid inheritance in bees, wasps, and ants generates relatedness asymmetries that promote the evolution of altruism by females, who are less related to their offspring than to their sisters ('supersister' relatedness). However, a consensus holds that relatedness asymmetry can only drive the evolution of eusociality if workers can direct their help preferentially to sisters over brothers, either through sex-ratio biases or a pre-existing ability to discriminate sexes among the brood. We show via a kin selection model that a simple feature of insect biology can promote the origin of workers in haplodiploids without requiring either condition. In insects in which females must found and provision new nests, body quality may have a stronger influence on female fitness than on male fitness. If altruism boosts the quality of all larval siblings, sisters may, therefore, benefit more than brothers from receiving the same amount of help. Accordingly, the benefits of altruism would fall disproportionately on supersisters in haplodiploids. Haplodiploid females should be more prone to altruism than diplodiploid females or males of either ploidy when altruism elevates female fitness especially, and even when altruists are blind to sibling sex.}, } @article {pmid32180428, year = {2020}, author = {Tanskanen, AO and Danielsbacka, M and Rotkirch, A}, title = {Grandparental Childcare for Biological, Adopted, and Step-Offspring: Findings From Cross-National Surveys.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {18}, number = {1}, pages = {1474704920907894}, pmid = {32180428}, issn = {1474-7049}, support = {HHSN271201300071C/AG/NIA NIH HHS/United States ; }, mesh = {Adult ; Aged ; Female ; Humans ; Male ; Middle Aged ; *Adult Children/statistics & numerical data ; *Child Rearing ; *Child, Adopted/statistics & numerical data ; Europe ; *Grandparents ; *Intergenerational Relations ; }, abstract = {Based on kin selection theory, amounts of grandparental investment should reflect the probability to share common genes with offspring. Adoption may represent a special case, however, yet grandparental investment in adopted children has previously been both theoretically misconstrued and little investigated. Here, we study for the first time how grandparental childcare provision is distributed between biological, adopted, and step-offspring. Using Generations and Gender Surveys (n = 15,168 adult child-grandmother and 12,193 adult child-grandfather dyads) and the Survey of Health, Ageing, and Retirement in Europe (n = 17,233 grandmother-adult child and 13,000 grandfather-adult child dyads), we find that grandparents were less likely to provide care to stepchildren than to adopted and biological children, but no difference between adopted and biological children. These findings were present in both data sets and for both grandmothers and grandfathers, after several potentially confounding factors were taken into account. The stepchild disadvantage is in line with kin selection theory. The congruent amounts of care provided to adopted and biological children may reflect similar levels of adult-child attachment, selection effects, and greater need in adoptive families, as well as some degree of genetical relatedness in the case of kin adoption. The study provides new evidence of biased kin investments in contemporary societies and stresses the importance of psychological motivation and attachment in evolutionary studies of kin investment.}, } @article {pmid32166391, year = {2020}, author = {Ruf, T and Bieber, C}, title = {Use of social thermoregulation fluctuates with mast seeding and reproduction in a pulsed resource consumer.}, journal = {Oecologia}, volume = {192}, number = {4}, pages = {919-928}, pmid = {32166391}, issn = {1432-1939}, support = {P 20534//Austrian Science Fund/ ; P 25023//Austrian Science Fund/ ; }, mesh = {Animals ; Body Temperature Regulation ; Female ; Horses ; Male ; *Myoxidae ; Reproduction ; Social Behavior ; }, abstract = {Edible dormice (Glis glis) can remain entirely solitary but frequently share sleeping sites with conspecifics in groups of up to 16 adults and yearlings. Here, we analysed grouping behaviour of 4564 marked individuals, captured in a 13-year study in nest boxes in a deciduous forest. We aimed to clarify (i) whether social thermoregulation is the primary cause for group formation and (ii) which factors affect group size and composition. Dormice temporarily formed both mixed and single-sex groups in response to acute cold ambient temperatures, especially those individuals with small body mass. Thus, thermoregulatory huddling appears to be the driving force for group formation in this species. Huddling was avoided-except for conditions of severe cold load-in years of full mast seeding, which is associated with reproduction and high foraging activity. Almost all females remained solitary during reproduction and lactation. Hence, entire populations of dormice switched between predominantly solitary lives in reproductive years to social behaviour in non-reproductive years. Non-social behaviour pointed to costs of huddling in terms of competition for local food resources even when food is generally abundant. The impact of competition was mitigated by a sex ratio that was biased towards males, which avoids sharing of food resources with related females that have extremely high energy demands during lactation. Importantly, dormice preferentially huddled in male-biased groups with litter mates from previous years. The fraction of related individuals increased with group size. Hence, group composition partly offsets the costs of shared food resources via indirect fitness benefits.}, } @article {pmid32165158, year = {2020}, author = {Van Cleve, J}, title = {Building a synthetic basis for kin selection and evolutionary game theory using population genetics.}, journal = {Theoretical population biology}, volume = {133}, number = {}, pages = {65-70}, doi = {10.1016/j.tpb.2020.03.001}, pmid = {32165158}, issn = {1096-0325}, mesh = {*Biological Evolution ; *Game Theory ; Genetics, Population ; Population Dynamics ; Selection, Genetic ; }, } @article {pmid32146892, year = {2020}, author = {Lehtonen, J}, title = {The Price equation and the unity of social evolution theory.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {375}, number = {1797}, pages = {20190362}, pmid = {32146892}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; Genetics, Population/*methods ; *Models, Genetic ; *Selection, Genetic ; *Social Evolution ; }, abstract = {The Price equation has been entangled with social evolution theory from the start. It has been used to derive the most general versions of kin selection theory, and Price himself produced a multilevel equation that provides an alternative formulation of social evolution theory, dividing selection into components between and within groups. In this sense, the Price equation forms a basis for both kin and group selection, so often pitted against each other in the literature. Contextual analysis and the neighbour approach are prominent alternatives for analysing group selection. I discuss these four approaches to social evolution theory and their connections to the Price equation, focusing on their similarities and common mathematical structure. Despite different notations and modelling traditions, all four approaches are ultimately linked by a common set of mathematical components, revealing their underlying unity in a transparent way. The Price equation can similarly be used in the derivation of streamlined, weak selection social evolution modelling methods. These weak selection models are practical and powerful methods for constructing models in evolutionary and behavioural ecology; they can clarify the causal structure of models, and can be easily converted between the four social evolution approaches just like their regression counterparts. This article is part of the theme issue 'Fifty years of the Price equation'.}, } @article {pmid32123093, year = {2020}, author = {Criscione, CD and van Paridon, BJ and Gilleard, JS and Goater, CP}, title = {Clonemate cotransmission supports a role for kin selection in a puppeteer parasite.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {117}, number = {11}, pages = {5970-5976}, pmid = {32123093}, issn = {1091-6490}, mesh = {Animals ; Ants/parasitology/physiology ; Behavior, Animal ; *Biological Evolution ; Dicrocoelium/parasitology ; Host-Parasite Interactions/genetics/*physiology ; Larva ; Parasites/*physiology ; Pedigree ; Snails/parasitology ; Trematoda/genetics/physiology ; }, abstract = {Host manipulation by parasites is a fascinating evolutionary outcome, but adaptive scenarios that often accompany even iconic examples in this popular field of study are speculative. Kin selection has been invoked as a means of explaining the evolution of an altruistic-based, host-manipulating behavior caused by larvae of the lancet fluke Dicrocoelium dendriticum in ants. Specifically, cotransmission of larval clonemates from a snail first host to an ant second host is presumed to lead to a puppeteer parasite in the ant's brain that has clonemates in the ant abdomen. Clonal relatedness between the actor (brain fluke) and recipients (abdomen flukes) enables kin selection of the parasite's host-manipulating trait, which facilitates transmission of the recipients to the final host. However, the hypothesis that asexual reproduction in the snail leads to a high abundance of clonemates in the same ant is untested. Clonal relationships between the manipulator in the brain and the nonmanipulators in the abdomen are also untested. We provide empirical data on the lancet fluke's clonal diversity within its ant host. In stark contrast to other trematodes, which do not exhibit the same host-manipulating behavioral trait, the lancet fluke has a high abundance of clonemates. Moreover, our data support existing theory that indicates that the altruistic behavior can evolve even in the presence of multiple clones within the same ant host. Importantly, our analyses conclusively show clonemate cotransmission into ants, and, as such, we find support for kin selection to drive the evolution and maintenance of this iconic host manipulation.}, } @article {pmid32117125, year = {2020}, author = {Kaundal, S and Deep, A and Kaur, G and Thakur, KG}, title = {Molecular and Biochemical Characterization of YeeF/YezG, a Polymorphic Toxin-Immunity Protein Pair From Bacillus subtilis.}, journal = {Frontiers in microbiology}, volume = {11}, number = {}, pages = {95}, pmid = {32117125}, issn = {1664-302X}, abstract = {Polymorphic toxins are important and widespread elements of bacterial warfare that help in restricting the growth of competitors, aiding kin selection, and shaping the bacterial communities. Although widespread, polymorphic toxin systems (PTS) have been extensively studied in Gram-negative bacteria, there are limited studies describing PTS in Gram-positive bacteria. The present study characterizes YeeF/YezG, a predicted member of a PF04740 family of the polymorphic toxin-immunity system from a Gram-positive bacteria Bacillus subtilis. The expression of the C-terminal toxic domain of YeeF (YeeF-CT) causes growth inhibition and gross morphological changes in Escherichia coli. The observed toxic effects are neutralized by the co-expression of yezG, a gene present downstream of yeeF, confirming YeeF-CT/YezG as a toxin/immunity protein pair. Biochemical and in vivo studies reveal that YeeF-CT causes toxicity due to its non-specific metal-dependent DNase activity. This is different from the previously reported RNase activity from the three B. subtilis toxins belonging to PF04740 family. Isothermal titration calorimetry (ITC) data analysis suggests that YeeF-CT binds YezG with a dissociation constant in the nanomolar range. Analytical ultracentrifugation studies revealed that YeeF-CT forms a homodimer and binds with two molecules of monomeric YezG immunity protein to form a 2:2 stochiometric heterotetrameric complex. Biolayer interferometry and electrophoretic mobility shift assays show that YeeF-CT/YezG/DNA forms a stable ternary complex implicating that YezG is an exosite inhibitor of YeeF-CT. This study extends the molecular targets of the toxins in the PF04740 family and thus, this family of toxins can be broadly classified as nucleases harboring either DNases or RNases activities.}, } @article {pmid32108343, year = {2020}, author = {Stockmaier, S and Bolnick, DI and Page, RA and Carter, GG}, title = {Sickness effects on social interactions depend on the type of behaviour and relationship.}, journal = {The Journal of animal ecology}, volume = {89}, number = {6}, pages = {1387-1394}, doi = {10.1111/1365-2656.13193}, pmid = {32108343}, issn = {1365-2656}, mesh = {Animals ; *Chiroptera ; Food ; Grooming ; Social Behavior ; *Social Interaction ; }, abstract = {Infections can change social behaviour in multiple ways, with profound impacts on pathogen transmission. However, these impacts might depend on the type of behaviour, how sociality as a biological trait is defined (e.g. network degree vs. mean edge strength) and the type of social relationship between the interacting individuals. We used the highly social common vampire bat Desmodus rotundus to test how an immune challenge by lipopolysaccharide (LPS) injections affects two different social behaviours and three alternate measures of sociality, and whether the LPS effect differs by kinship relationship. Effects of sickness should be lower for social behaviours that bestow greater benefits to inclusive fitness, such as food sharing. As predicted, immune-challenged bats experienced a greater reduction in allogrooming received than food sharing received. Sickness effects might also depend on how a social interaction is defined (e.g. the number of grooming partners vs. the duration of grooming events). We predicted that sickness would impact both the number and duration of social encounters, but we only detected a decrease in the number of grooming partners. Finally, sickness effects might vary with social relationship type. We predicted that sickness effects should be smaller for interactions among close kin. As expected, the immune challenge had smaller effects on mother-offspring interactions. In conclusion, our results highlight the need to explicitly consider how the effects of sickness on social network structure can differ depending on the 'who, what, and how' of social interactions, because these factors are likely to influence how sickness behaviour alters pathogen transmission.}, } @article {pmid32099082, year = {2020}, author = {Lobmaier, JS and Probst, F and Fischbacher, U and Wirthmüller, U and Knoch, D}, title = {Pleasant body odours, but not genetic similarity, influence trustworthiness in a modified trust game.}, journal = {Scientific reports}, volume = {10}, number = {1}, pages = {3388}, pmid = {32099082}, issn = {2045-2322}, mesh = {Adult ; HLA Antigens/*genetics/metabolism ; Humans ; Linear Models ; Male ; *Smell ; Trust ; Young Adult ; }, abstract = {Identifying trustworthy partners is an important adaptive challenge for establishing mutually cooperative relationships. Previous studies have demonstrated a marked relationship between a person's attractiveness and his apparent trustworthiness (beauty premium). Kin selection theory, however, suggests that cues to kinship enhance trustworthiness. Here we directly tested predictions of the beauty premium and kin selection theory by using body odours as cues to trustworthiness. Body odours reportedly portray information about an individuals' genotype at the human leucocyte antigen system (HLA) and thus olfactory cues in body odours serve as a promising means for kin recognition. Ninety men played trust games in which they divided uneven sums of monetary units between two male trustees represented by their body odour and rated each body odour for pleasantness. Half of the odours came from HLA-similar men (suggesting closer kin) and half from HLA dissimilar men (suggesting non-kin). We found that the amount of money the players transferred was not related to HLA-similarity, but to the pleasantness of the trustee's body odour. By showing that people with more pleasant body odours are trusted more than people with unpleasant body odour we provide evidence for a "beauty-premium" that overrides any putative effect of kin.}, } @article {pmid32097598, year = {2020}, author = {Poirotte, C and Charpentier, MJE}, title = {Unconditional care from close maternal kin in the face of parasites.}, journal = {Biology letters}, volume = {16}, number = {2}, pages = {20190869}, pmid = {32097598}, issn = {1744-957X}, mesh = {Animals ; Family ; Grooming ; *Parasites ; Primates ; Social Behavior ; }, abstract = {Several species mitigate relationships according to their conspecifics' parasite status. Yet, this defence strategy comes with the costs of depriving individuals from valuable social bonds. Animals therefore face a trade-off between the costs of pathogen exposure and the benefits of social relationships. According to the models of social evolution, social bonds are highly kin-biased. However, whether kinship mitigates social avoidance of contagious individuals has never been tested so far. Here, we build on previous research to demonstrate that mandrills (Mandrillus sphinx) modulate social avoidance of contagious individuals according to kinship: individuals do not avoid grooming their close maternal kin when contagious (parasitized with oro-faecally transmitted protozoa), although they do for more distant or non-kin. While individuals' parasite status has seldom been considered as a trait impacting social relationships in animals, this study goes a step beyond by showing that kinship balances the effect of health status on social behaviour in a non-human primate.}, } @article {pmid37588371, year = {2020}, author = {Micheletti, AJC and Ruxton, GD and Gardner, A}, title = {The demography of human warfare can drive sex differences in altruism.}, journal = {Evolutionary human sciences}, volume = {2}, number = {}, pages = {e7}, pmid = {37588371}, issn = {2513-843X}, abstract = {Recent years have seen great interest in the suggestion that between-group aggression and within-group altruism have coevolved. However, these efforts have neglected the possibility that warfare - via its impact on demography - might influence human social behaviours more widely, not just those directly connected to success in war. Moreover, the potential for sex differences in the demography of warfare to translate into sex differences in social behaviour more generally has remained unexplored. Here, we develop a kin-selection model of altruism performed by men and women for the benefit of their groupmates in a population experiencing intergroup conflict. We find that warfare can promote altruistic, helping behaviours as the additional reproductive opportunities winners obtain in defeated groups decrease harmful competition between kin. Furthermore, we find that sex can be a crucial modulator of altruism, with there being a tendency for the sex that competes more intensely with relatives to behave more altruistically and for the sex that competes more intensely with non-relatives in defeated groups to receive more altruism. In addition, there is also a tendency for the less-dispersing sex to both give and receive more altruism. We discuss implications for our understanding of observed sex differences in cooperation in human societies.}, } @article {pmid32064318, year = {2019}, author = {Kappeler, PM and Pozzi, L}, title = {Evolutionary transitions toward pair living in nonhuman primates as stepping stones toward more complex societies.}, journal = {Science advances}, volume = {5}, number = {12}, pages = {eaay1276}, pmid = {32064318}, issn = {2375-2548}, mesh = {Animals ; Behavior, Animal ; *Biological Evolution ; Evolution, Molecular ; Phylogeny ; *Primates/classification/genetics ; Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {Nonhuman primate societies vary tremendously in size and composition, but how and why evolutionary transitions among different states occurred remains highly controversial. In particular, how many times pair living evolved and the social states of the ancestors of pair- and group-living species remains contentious. We examined evolutionary transitions in primate social evolution by using new, independent categorizations of sociality and different phylogenetic hypotheses with a vastly expanded dataset. Using Bayesian phylogenetic comparative methods, we consistently found the strongest support for a model that invokes frequent transitions between solitary ancestors and pair-living descendants, with the latter giving rise to group-living species. This result was robust to systematic variation in social classification, sample size, and phylogeny. Our analyses therefore indicate that pair living was a stepping stone in the evolution of structurally more complex primate societies, a result that bolsters the role of kin selection in social evolution.}, } @article {pmid32055412, year = {2020}, author = {Patel, M and West, SA and Biernaskie, JM}, title = {Kin discrimination, negative relatedness, and how to distinguish between selfishness and spite.}, journal = {Evolution letters}, volume = {4}, number = {1}, pages = {65-72}, pmid = {32055412}, issn = {2056-3744}, support = {BB/M011224/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Spiteful behaviors occur when an actor harms its own fitness to inflict harm on the fitness of others. Several papers have predicted that spite can be favored in sufficiently small populations, even when the harming behavior is directed indiscriminately at others. However, it is not clear that truly spiteful behavior could be favored without the harm being directed at a subset of social partners with relatively low genetic similarity to the actor (kin discrimination, causing a negative relatedness between actor and harmed recipient). Using mathematical models, we show that (1) the evolution of spite requires kin discrimination; (2) previous models suggesting indiscriminate spite involve scenarios where the actor gains a direct feedback benefit from harming others, and so the harming is selfish rather than spiteful; (3) extreme selfishness can be favored in small populations (or, more generally, under local competition) because this is where the direct feedback benefit of harming is greatest.}, } @article {pmid31964305, year = {2020}, author = {Montazeaud, G and Rousset, F and Fort, F and Violle, C and Fréville, H and Gandon, S}, title = {Farming plant cooperation in crops.}, journal = {Proceedings. Biological sciences}, volume = {287}, number = {1919}, pages = {20191290}, pmid = {31964305}, issn = {1471-2954}, mesh = {*Agriculture ; Biological Evolution ; Crops, Agricultural/*genetics ; Domestication ; Farms ; Phenotype ; Selection, Genetic ; }, abstract = {Selection of the fittest can promote individual competitiveness but often results in the erosion of group performance. Recently, several authors revisited this idea in crop production and proposed new practices based on selection for cooperative phenotypes, i.e. phenotypes that increase crop yield through decreased competitiveness. These recommendations, however, remain difficult to evaluate without a formal description of crop evolutionary dynamics under different selection strategies. Here, we develop a theoretical framework to investigate the evolution of cooperation-related traits in crops, using plant height as a case study. Our model is tailored to realistic agricultural practices and shows that combining high plant density, high relatedness and selection among groups favours the evolution of shorter plants that maximize grain yield. Our model allows us to revisit past and current breeding practices in light of kin selection theory, and yields practical recommendations to increase cooperation among crops and promote sustainable agriculture.}, } @article {pmid31945069, year = {2020}, author = {Komatsu, H and Kubota, H and Tanaka, N and Ohashi, H}, title = {Designing information provision to serve as a reminder of altruistic benefits: A case study of the risks of air pollution caused by industrialization.}, journal = {PloS one}, volume = {15}, number = {1}, pages = {e0227024}, pmid = {31945069}, issn = {1932-6203}, mesh = {Adult ; Air Pollution/*adverse effects ; *Altruism ; Attitude ; Family/psychology ; Humans ; *Industrial Development ; Internet ; Middle Aged ; *Risk Assessment ; Surveys and Questionnaires ; }, abstract = {A well-known phenomenon is that humans perceive risks to threaten future generations as more dangerous in many cases. However, this tendency could be changed depending on certain conditions and could potentially be explained by the evolution of altruism. Our multi-agent simulation model, which was constructed to identify attributes contributing to subjective assessment of a risk source based on kin selection theory, showed that support from relatives can affect the agents' subjective risk assessment. We utilize this insight, which has never been explored in the context of nudge, to show that real-world messages reminding respondents that they are supported by their relatives can moderate the perception of a risk source as extremely dangerous. A randomized control trial based on an internet questionnaire survey was conducted to identify the intervention effect of such messages, using air pollution caused by industrialization as the risk source for the case study. Our analysis suggests that messages moderate extreme attitudes. Presentation of additional visual information can boost the sense of familial support and increase the effect of a message compared with a message comprising only textual information. The attributes and personality traits of the respondents who are responsive to the intervention message are also discussed.}, } @article {pmid31928868, year = {2020}, author = {Brucks, D and von Bayern, AMP}, title = {Parrots Voluntarily Help Each Other to Obtain Food Rewards.}, journal = {Current biology : CB}, volume = {30}, number = {2}, pages = {292-297.e5}, doi = {10.1016/j.cub.2019.11.030}, pmid = {31928868}, issn = {1879-0445}, mesh = {Animals ; Behavior, Animal ; Female ; Food ; Male ; *Parrots ; *Reward ; *Social Behavior ; Species Specificity ; }, abstract = {Helping others to obtain benefits, even at a cost to oneself, poses an evolutionary puzzle [1]. While kin selection explains such "selfless" acts among relatives, only reciprocity (paying back received favors) entails fitness benefits for unrelated individuals [2]. So far, experimental evidence for both prosocial helping (providing voluntary assistance for achieving an action-based goal) and reciprocity has been reported in a few mammals but no avian species [3]. In order to gain insights into the evolutionary origins of these behaviors, the capacity of non-mammalian species for prosociality and for reciprocity needs to be investigated. We tested two parrot species in an instrumental-helping paradigm involving "token transfer." Here, actors could provide tokens to their neighbor, who could exchange them with an experimenter for food. To verify whether the parrots understood the task's contingencies, we systematically varied the presence of a partner and the possibility for exchange. We found that African grey parrots voluntarily and spontaneously transferred tokens to conspecific partners, whereas significantly fewer transfers occurred in the control conditions. Transfers were affected by the strength of the dyads' affiliation and partially by the receivers' attention-getting behaviors. Furthermore, the birds reciprocated the help once the roles were reversed. Blue-headed macaws, in contrast, transferred hardly any tokens. Species differences in social tolerance might explain this discrepancy. These findings show that instrumental helping based on a prosocial attitude, accompanied but potentially not sustained by reciprocity, is present in parrots, suggesting that this capacity evolved convergently in this avian group and mammals.}, } @article {pmid31897909, year = {2020}, author = {Chaves, ÓM and Martins, V and Camaratta, D and Bicca-Marques, JC}, title = {Successful adoption of an orphan infant in a wild group of brown howler monkeys.}, journal = {Primates; journal of primatology}, volume = {61}, number = {2}, pages = {301-307}, pmid = {31897909}, issn = {1610-7365}, support = {PQ # 303154/2009-8, 303306/2013-0 and 304475/2018-1//Brazilian National Research Council/ ; 2755/2010//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; 1464332//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; }, mesh = {Alouatta/*physiology ; Animal Nutritional Physiological Phenomena ; Animals ; Brazil ; Diet/veterinary ; Feeding Behavior ; Female ; Lactation ; Male ; *Maternal Behavior ; Plant Leaves ; }, abstract = {The rarity of infant adoption in wild primates compromises our understanding of its consequences for the participating individuals. We report the first case of successful infant adoption in a wild group of brown howler monkeys (Alouatta guariba clamitans). We evaluated the potential costs of the behavior for the adoptive mother by comparing her activity budget and diet before and after the adoption. On 18 June 2013, a domestic dog killed the mother of a 2-month-old male infant (Victorio) as she attempted to cross a canopy gap. Victorio was immediately rescued from her belly by a researcher and released in a climber near another infant-carrying female (Sofia, his likely grandmother). Sofia recovered him 2 min later. She carried and breastfed both infants during the next 4 weeks, when her own infant disappeared. We monitored Victorio until he reached adulthood in March 2018. Sofia fed more (mainly on immature leaves) when she nursed only Victorio than when nursing only her own or both infants. Assuming that the disappearance of Sofia's own infant was unrelated to the adoption of Victorio, we conclude that his successful adoption may contribute to Sofia's inclusive fitness if he sires his own infants.}, } @article {pmid31833181, year = {2020}, author = {Martinig, AR and McAdam, AG and Dantzer, B and Lane, JE and Coltman, DW and Boutin, S}, title = {The new kid on the block: immigrant males win big whereas females pay fitness cost after dispersal.}, journal = {Ecology letters}, volume = {23}, number = {3}, pages = {430-438}, doi = {10.1111/ele.13436}, pmid = {31833181}, issn = {1461-0248}, mesh = {Breeding ; Canada ; *Emigrants and Immigrants ; Female ; Humans ; Male ; *Reproduction ; }, abstract = {Dispersal is nearly universal; yet, which sex tends to disperse more and their success thereafter depends on the fitness consequences of dispersal. We asked if lifetime fitness differed between residents and immigrants (successful between-population dispersers) and their offspring using 29 years of monitoring from North American red squirrels (Tamiasciurus hudsonicus) in Canada. Compared to residents, immigrant females had 23% lower lifetime breeding success (LBS), while immigrant males had 29% higher LBS. Male immigration and female residency were favoured. Offspring born to immigrants had 15-43% lower LBS than offspring born to residents. We conclude that immigration benefitted males, but not females, which appeared to be making the best of a bad lot. Our results are in line with male-biased dispersal being driven by local mate competition and local resource enhancement, while the intergenerational cost to immigration is a new complication in explaining the drivers of sex-biased dispersal.}, } @article {pmid31818941, year = {2019}, author = {Nattrass, S and Croft, DP and Ellis, S and Cant, MA and Weiss, MN and Wright, BM and Stredulinsky, E and Doniol-Valcroze, T and Ford, JKB and Balcomb, KC and Franks, DW}, title = {Postreproductive killer whale grandmothers improve the survival of their grandoffspring.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {52}, pages = {26669-26673}, pmid = {31818941}, issn = {1091-6490}, abstract = {Understanding why females of some mammalian species cease ovulation prior to the end of life is a long-standing interdisciplinary and evolutionary challenge. In humans and some species of toothed whales, females can live for decades after stopping reproduction. This unusual life history trait is thought to have evolved, in part, due to the inclusive fitness benefits that postreproductive females gain by helping kin. In humans, grandmothers gain inclusive fitness benefits by increasing their number of surviving grandoffspring, referred to as the grandmother effect. Among toothed whales, the grandmother effect has not been rigorously tested. Here, we test for the grandmother effect in killer whales, by quantifying grandoffspring survival with living or recently deceased reproductive and postreproductive grandmothers, and show that postreproductive grandmothers provide significant survival benefits to their grandoffspring above that provided by reproductive grandmothers. This provides evidence of the grandmother effect in a nonhuman menopausal species. By stopping reproduction, grandmothers avoid reproductive conflict with their daughters, and offer increased benefits to their grandoffspring. The benefits postreproductive grandmothers provide to their grandoffspring are shown to be most important in difficult times where the salmon abundance is low to moderate. The postreproductive grandmother effect we report, together with the known costs of late-life reproduction in killer whales, can help explain the long postreproductive life spans of resident killer whales.}, } @article {pmid31805037, year = {2019}, author = {Thomas, F and Giraudeau, M and Renaud, F and Ujvari, B and Roche, B and Pujol, P and Raymond, M and Lemaitre, JF and Alvergne, A}, title = {Can postfertile life stages evolve as an anticancer mechanism?.}, journal = {PLoS biology}, volume = {17}, number = {12}, pages = {e3000565}, pmid = {31805037}, issn = {1545-7885}, mesh = {Adaptation, Physiological/*physiology ; Animals ; Biological Evolution ; Female ; Humans ; Menopause/metabolism/*physiology ; Neoplasms/physiopathology/*prevention & control ; Reproduction/physiology ; }, abstract = {Why a postfertile stage has evolved in females of some species has puzzled evolutionary biologists for over 50 years. We propose that existing adaptive explanations have underestimated in their formulation an important parameter operating both at the specific and the individual levels: the balance between cancer risks and cancer defenses. During their life, most multicellular organisms naturally accumulate oncogenic processes in their body. In parallel, reproduction, notably the pregnancy process in mammals, exacerbates the progression of existing tumors in females. When, for various ecological or evolutionary reasons, anticancer defenses are too weak, given cancer risk, older females could not pursue their reproduction without triggering fatal metastatic cancers, nor even maintain a normal reproductive physiology if the latter also promotes the growth of existing oncogenic processes, e.g., hormone-dependent malignancies. At least until stronger anticancer defenses are selected for in these species, females could achieve higher inclusive fitness by ceasing their reproduction and/or going through menopause (assuming that these traits are easier to select than anticancer defenses), thereby limiting the risk of premature death due to metastatic cancers. Because relatively few species experience such an evolutionary mismatch between anticancer defenses and cancer risks, the evolution of prolonged life after reproduction could also be a rare, potentially transient, anticancer adaptation in the animal kingdom.}, } @article {pmid31795864, year = {2019}, author = {Gow, EA and Arcese, P and Dagenais, D and Sardell, RJ and Wilson, S and Reid, JM}, title = {Testing predictions of inclusive fitness theory in inbreeding relatives with biparental care.}, journal = {Proceedings. Biological sciences}, volume = {286}, number = {1916}, pages = {20191933}, pmid = {31795864}, issn = {1471-2954}, mesh = {Animals ; Female ; *Inbreeding ; Male ; Passeriformes/*physiology ; *Sexual Behavior, Animal ; }, abstract = {Inclusive fitness theory predicts that parental care will vary with relatedness between potentially caring parents and offspring, potentially shaping mating system evolution. Systems with extra-pair paternity (EPP), and hence variable parent-brood relatedness, provide valuable opportunities to test this prediction. However, existing theoretical and empirical studies assume that a focal male is either an offspring's father with no inbreeding, or is completely unrelated. We highlight that this simple dichotomy does not hold given reproductive interactions among relatives, complicating the effect of EPP on parent-brood relatedness yet providing new opportunities to test inclusive fitness theory. Accordingly, we tested hierarchical hypotheses relating parental feeding rate to parent-brood relatedness, parent kinship and inbreeding, using song sparrows (Melospiza melodia) experiencing natural variation in relatedness. As predicted, male and female feeding rates increased with relatedness to a dependent brood, even controlling for brood size. Male feeding rate tended to decrease as paternity loss increased, and increased with increasing kinship and hence inbreeding between socially paired mates. We thereby demonstrate that variation in a key component of parental care concurs with subtle predictions from inclusive fitness theory. We additionally highlight that such effects can depend on the underlying social mating system, potentially generating status-specific costs of extra-pair reproduction.}, } @article {pmid31790440, year = {2019}, author = {Fumagalli, SE and Rice, SH}, title = {Stochasticity and non-additivity expose hidden evolutionary pathways to cooperation.}, journal = {PloS one}, volume = {14}, number = {12}, pages = {e0225517}, pmid = {31790440}, issn = {1932-6203}, mesh = {Animals ; Behavior, Animal ; *Biological Evolution ; *Cooperative Behavior ; *Models, Biological ; Stochastic Processes ; }, abstract = {Cooperation is widespread across the tree of life, with examples ranging from vertebrates to lichens to multispecies biofilms. The initial evolution of such cooperation is likely to involve interactions that produce non-additive fitness effects among small groups of individuals in local populations. However, most models for the evolution of cooperation have focused on genealogically related individuals, assume that the factors influencing individual fitness are deterministic, that populations are very large, and that the benefits of cooperation increase linearly with the number of cooperative interactions. Here we show that stochasticity and non-additive interactions can facilitate the evolution of cooperation in small local groups. We derive a generalized model for the evolution of cooperation and show that if cooperation reduces the variance in individual fitness (separate from its effect on average fitness), this can aid in the evolution of cooperation through directional stochastic effects. In addition, we show that the potential for the evolution of cooperation is influenced by non-additivity in benefits with cooperation being more likely to evolve when the marginal benefit of a cooperative act increases with the number of such acts. Our model compliments traditional cooperation models (kin selection, reciprocal cooperation, green beard effect, etc.) and applies to a broad range of cooperative interactions seen in nature.}, } @article {pmid31729694, year = {2019}, author = {Clech, L and Hazel, A and Gibson, MA}, title = {Does Kin-Selection Theory Help to Explain Support Networks among Farmers in South-Central Ethiopia?.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {30}, number = {4}, pages = {422-447}, pmid = {31729694}, issn = {1936-4776}, support = {F/00182/BI//Leverhulme Trust Research Grant/ ; }, mesh = {Adult ; *Birth Order ; *Competitive Behavior ; Ethiopia/ethnology ; Family Relations/*ethnology ; *Farmers ; Humans ; Psychological Theory ; *Psychosocial Support Systems ; Sibling Relations/ethnology ; }, abstract = {Social support networks play a key role in human livelihood security, especially in vulnerable communities. Here we explore how evolutionary ideas of kin selection and intrahousehold resource competition can explain individual variation in daily support network size and composition in a south-central Ethiopian agricultural community. We consider both domestic and agricultural help across two generations with different wealth-transfer norms that yield different contexts for sibling competition. For farmers who inherited land rights from family, firstborns were more likely to report daily support from parents and to have larger nonparental kin networks (n = 180). Compared with other farmers, firstborns were also more likely to reciprocate their parents' support, and to help nonparental kin without reciprocity. For farmers who received land rights from the government (n = 151), middle-born farmers reported more nonparental kin in their support networks compared with other farmers; nonreciprocal interactions were particularly common in both directions. This suggests a diversification of adult support networks to nonparental kin, possibly in response to a long-term parental investment disadvantage of being middle-born sons. In all instances, regardless of inheritance, lastborn farmers were the most disadvantaged in terms of kin support. Overall, we found that nonreciprocal interactions among farmers followed kin selection predictions. Direct reciprocity explained a substantial part of the support received from kin, suggesting the importance of the combined effects of kin selection and reciprocity for investment from kin.}, } @article {pmid31729693, year = {2019}, author = {Boesch, L and Berger, R}, title = {Explaining Fairness : Results from an Experiment in Guinea.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {30}, number = {4}, pages = {398-421}, pmid = {31729693}, issn = {1936-4776}, mesh = {Adult ; Family/*ethnology ; *Group Processes ; Guinea/ethnology ; Humans ; *Morals ; *Social Behavior ; *Social Perception ; }, abstract = {Fairness is undoubtedly an essential normative concept in humans and promotes cooperation in human societies. The fact that fairness exists is puzzling, however, because it works against the short-term interest of individuals. Theories of genetic evolution, cultural evolution, and gene-culture coevolution identify plausible mechanisms for the evolution of fairness in humans. Such mechanisms include kin selection, the support of group-beneficial moral norms through ethnic markers, free partner choice with equal outside options, and free partner choice with reputation as well as spite in small populations. Here, we present the results of a common-pool resource game experiment on sharing. Based on data from 37 multiethnic villages in a subsistence agricultural population in Foutah Djallon, Guinea, we show that fair behavior in our experiment increased with increasing ethnic homogeneity and market integration. Group size and kinship had the opposite effect. Overall, fair behavior was not conditional on reputation. Instead, the ability of the different village populations to support individuals' fairness in situations lacking the opportunity to build a positive reputation varied significantly. Our results suggest that evolutionary theory provides a useful framework for the analysis of fairness in humans.}, } @article {pmid31713849, year = {2020}, author = {Winnicki, SK and Munguía, SM and Williams, EJ and Boyle, WA}, title = {Social interactions do not drive territory aggregation in a grassland songbird.}, journal = {Ecology}, volume = {101}, number = {2}, pages = {e02927}, doi = {10.1002/ecy.2927}, pmid = {31713849}, issn = {1939-9170}, support = {DBI-140802//Kansas State University (KSU) Biology National Science Foundation (NSF) REU Program/International ; //EPSCoR 1st Award/International ; DEB-175449//NSF/International ; //NSF Graduate Research Fellowship/International ; //Sigma Xi Grant-in-Aid of Research/International ; //Kansas Ornithological Society/International ; }, mesh = {Animals ; Ecosystem ; Grassland ; Interpersonal Relations ; Male ; *Passeriformes ; *Songbirds ; }, abstract = {Understanding the drivers of animal distributions is a fundamental goal of ecology and informs habitat management. The costs and benefits of colonial aggregations in animals are well established, but the factors leading to aggregation in territorial animals remain unclear. Territorial animals might aggregate to facilitate social behavior such as (1) group defense from predators and/or parasites, (2) cooperative care of offspring, (3) extra-pair mating, and/or (4) mitigating costs of extra-pair mating through kin selection. Using experimental and observational methods, we tested predictions of all four hypotheses in a tallgrass prairie in northeast Kansas, United States. Grasshopper Sparrow (Ammodramus savannarum) males formed clumps of territories in some parts of the site while leaving other apparently suitable areas unoccupied. Despite substantial sampling effort (653 territories and 223 nests), we found no support for any hypothesized social driver of aggregation, nor evidence that aggregation increases nest success. Our results run counter to previous evidence that conspecific interactions shape territory distributions. These results suggest one of the following alternatives: (1) the benefits of aggregation accrue to different life-history stages, or (2) the benefits of territory aggregation may be too small to detect in short-term studies and/or the consequences of aggregation are sufficiently temporally and spatially variable that they do not always appear to be locally adaptive, perhaps exacerbated by changing landscape contexts and declining population sizes.}, } @article {pmid31690488, year = {2020}, author = {Paternotte, C}, title = {Social evolution and the individual-as-maximising-agent analogy.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {79}, number = {}, pages = {101225}, doi = {10.1016/j.shpsc.2019.101225}, pmid = {31690488}, issn = {1879-2499}, mesh = {*Biological Evolution ; *Genetic Fitness ; Models, Biological ; Models, Genetic ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Does natural selection tend to maximise something? Does it produce individuals who act as if they maximised something? These questions have long occupied evolutionary theorists, and have proven especially tricky in the case of social evolution, which is known for leading to apparently suboptimal states. This paper investigates recent results about maximising analogies - especially regarding whether individuals should be considered as if they maximised their inclusive fitness - and compares the fruitfulness of global and local approaches. I assess Okasha & Martens's recent local approach to the individual-as-maximising-agent analogy and its robustness with respect to interactive situations. I then defend the relative merits of a comparable global approach, arguing that it is conceptually on a par and heuristically advantageous.}, } @article {pmid31650630, year = {2020}, author = {Keaney, TA and Wong, HWS and Dowling, DK and Jones, TM and Holman, L}, title = {Mother's curse and indirect genetic effects: Do males matter to mitochondrial genome evolution?.}, journal = {Journal of evolutionary biology}, volume = {33}, number = {2}, pages = {189-201}, doi = {10.1111/jeb.13561}, pmid = {31650630}, issn = {1420-9101}, mesh = {Animals ; Drosophila melanogaster/*genetics ; Female ; Genome, Mitochondrial/*genetics ; Male ; *Maternal Inheritance ; Selection, Genetic ; }, abstract = {Maternal inheritance of mitochondrial DNA (mtDNA) was originally thought to prevent any response to selection on male phenotypic variation attributable to mtDNA, resulting in a male-biased mtDNA mutation load ("mother's curse"). However, the theory underpinning this claim implicitly assumes that a male's mtDNA has no effect on the fitness of females he comes into contact with. If such "mitochondrially encoded indirect genetics effects" (mtIGEs) do in fact exist, and there is relatedness between the mitochondrial genomes of interacting males and females, male mtDNA-encoded traits can undergo adaptation after all. We tested this possibility using strains of Drosophila melanogaster that differ in their mtDNA. Our experiments indicate that female fitness is influenced by the mtDNA carried by males that the females encounter, which could plausibly allow the mitochondrial genome to evolve via kin selection. We argue that mtIGEs are probably common, and that this might ameliorate or exacerbate mother's curse.}, } @article {pmid31636937, year = {2019}, author = {Levin, SR and Caro, SM and Griffin, AS and West, SA}, title = {Honest signaling and the double counting of inclusive fitness.}, journal = {Evolution letters}, volume = {3}, number = {5}, pages = {428-433}, pmid = {31636937}, issn = {2056-3744}, abstract = {Inclusive fitness requires a careful accounting of all the fitness effects of a particular behavior. Verbal arguments can potentially exaggerate the inclusive fitness consequences of a behavior by including the fitness of relatives that was not caused by that behavior, leading to error. We show how this "double-counting" error can arise, with a recent example from the signaling literature. In particular, we examine the recent debate over whether parental divorce increases parent-offspring conflict, selecting for less honest signaling. We found that, when all the inclusive fitness consequences are accounted for, parental divorce increases conflict between siblings, in a way that they can select for less honest signaling. This prediction is consistent with the empirical data. More generally, our results illustrate how verbal arguments can be misleading, emphasizing the advantage of formal mathematical models.}, } @article {pmid31629289, year = {2019}, author = {Swedell, L and Plummer, T}, title = {Social evolution in Plio-Pleistocene hominins: Insights from hamadryas baboons and paleoecology.}, journal = {Journal of human evolution}, volume = {137}, number = {}, pages = {102667}, doi = {10.1016/j.jhevol.2019.102667}, pmid = {31629289}, issn = {1095-8606}, mesh = {Animals ; *Biological Evolution ; Female ; Hominidae/*psychology ; Kenya ; Male ; Papio hamadryas/*psychology ; *Social Behavior ; }, abstract = {Reconstructions of hominin evolution have long benefited from comparisons with nonhuman primates, especially baboons and chimpanzees. The hamadryas baboon (Papio hamadryas) is arguably one of the best such models, as it exhibits both the male kin bonding and the cross-sex pair bonding thought to have been important in hominin evolution. Here we link processes of behavioral evolution in hamadryas baboons with those in a Plio-Pleistocene hominin, provisionally identified as Homo erectus (sensu lato) - a pivotal species in that its larger body and brain size and wider ranging patterns increased female costs of reproduction, increasing the importance of sociality. The combination of these higher costs of reproduction and shifts in diet and food acquisition have previously been argued to have been alleviated either via strengthening of male-female bonds (involving male provisioning and the evolution of monogamy) or via the assistance of older, post-reproductive females (leading to post-reproductive longevity in females, i.e., the grandmother hypothesis). We suggest that both arrangements could have been present in Plio-Pleistocene hominins if they lived in multilevel societies. Here we expand on our earlier scenario with two sets of recent data in support of it, (1) archaeological data from the 2 million year old Oldowan site of Kanjera South, Kenya and other sites that are suggestive of tool dependent foraging on nutrient dense resources (animal carcasses and plant underground storage organs), cooperation, and food sharing; and (2) a pattern of genetic variation in hamadryas baboons that suggests the operation of kin selection among both males and females at multiple levels of society. Taken together, these two sets of data strengthen our model and support the idea of a complex society linked by male-male, male-female, and female-female bonds at multiple levels of social organization in Plio-Pleistocene hominins.}, } @article {pmid31624543, year = {2019}, author = {Nonacs, P}, title = {Reproductive skew in cooperative breeding: Environmental variability, antagonistic selection, choice, and control.}, journal = {Ecology and evolution}, volume = {9}, number = {18}, pages = {10163-10175}, pmid = {31624543}, issn = {2045-7758}, abstract = {A multitude of factors may determine reproductive skew among cooperative breeders. One explanation, derived from inclusive fitness theory, is that groups can partition reproduction such that subordinates do at least as well as noncooperative solitary individuals. The majority of recent data, however, fails to support this prediction; possibly because inclusive fitness models cannot easily incorporate multiple factors simultaneously to predict skew. Notable omissions are antagonistic selection (across generations, genes will be in both dominant and subordinate bodies), constraints on the number of sites suitable for successful reproduction, choice in which group an individual might join, and within-group control or suppression of competition. All of these factors and more are explored through agent-based evolutionary simulations. The results suggest the primary drivers for the initial evolution of cooperative breeding may be a combination of limited suitable sites, choice across those sites, and parental manipulation of offspring into helping roles. Antagonistic selection may be important when subordinates are more frequent than dominants. Kinship matters, but its main effect may be in offspring being available for manipulation while unrelated individuals are not. The greater flexibility of evolutionary simulations allows the incorporation of species-specific life histories and ecological constraints to better predict sociobiology.}, } @article {pmid31616483, year = {2019}, author = {Deng, K and Liu, W and Wang, DH}, title = {Relatedness and spatial distance modulate intergroup interactions: experimental evidence from a social rodent.}, journal = {Current zoology}, volume = {65}, number = {5}, pages = {527-534}, pmid = {31616483}, issn = {1674-5507}, abstract = {Kin selection theory predicts that individuals should generally behave less aggressively or more amicably towards relatives than nonkin. However, how individuals treat conspecifics depends on genetic relatedness but also on the ecological context, which influences the benefits and costs of their interactions. In this study, we used microsatellite DNA markers and behavioral tests to examine the influence of kinship and proximity on the social behavior of Mongolian gerbils Meriones unguiculatus living in different social groups, and whether these effects varied with sex and season. We recorded the duration of 4 behavioral categories (investigative, neutral, amicable, and agonistic) during a 10-min pairwise test. We found that genetic relatedness had significant effects on the duration of investigative, neutral, and amicable behavior, but not on agonistic behavior. We also found significant interaction effects of relatedness and distance between burrow systems (i.e., spatial distance) on investigative, neutral, and amicable behavior, which suggests that the effects of kinship on social behavior were restricted by spatial proximity. The interaction effect between sex and relatedness on amicable behavior showed that male gerbils became more intimate with individuals of the same sex that had higher pairwise relatedness than females. Furthermore, both male and female gerbils enhanced their aggression during the food-hoarding season, but the intensity of these changes was significantly higher in females. Overall, our results suggest that the effects of kinship and spatial proximity on social behavior exhibit sexual or seasonal patterns, thereby implying ecological context-dependent responses to out-group individuals in Mongolian gerbils.}, } @article {pmid31598313, year = {2019}, author = {Freeman, AR and Wood, TJ and Bairos-Novak, KR and Anderson, WG and Hare, JF}, title = {Gone girl: Richardson's ground squirrel offspring and neighbours are resilient to female removal.}, journal = {Royal Society open science}, volume = {6}, number = {9}, pages = {190904}, pmid = {31598313}, issn = {2054-5703}, abstract = {Within matrilineal societies, the presence of mothers and female kin can greatly enhance survival and reproductive success owing to kin-biased alarm calling, cooperation in territory defence, protection from infanticidal conspecifics, joint care of young and enhanced access to resources. The removal of mothers by predators or disease is expected to increase the stress experienced by offspring via activation of their hypothalamic-pituitary-adrenal axis, increasing circulating glucocorticoids and reducing offspring survival and reproductive success. Yet, few studies have removed mothers in the post-weaning period to examine the assumed physiological and fitness consequences associated with these mortality events. We examined how the loss of a mother affects juvenile Richardson's ground squirrels' (Urocitellus richardsonii) faecal glucocorticoid metabolites and their survival. Given that neighbours are often close kin, we further hypothesized that conspecific removal would similarly diminish the fitness of neighbouring individuals. Upon removing the mother, we detected no impact on offspring or neighbouring conspecific faecal glucocorticoid metabolites in the removal year, or on overwinter survival in the following year. Furthermore, no impact on neighbour reproductive success was detected. Given the high predation rates of ground squirrels in wild populations, resilience to a changing social environment would prove adaptive for both surviving kin and non-kin.}, } @article {pmid31578780, year = {2019}, author = {Hervey, SD and Barnas, AF and Stechmann, TJ and Rockwell, RF and Ellis-Felege, SN and Darby, BJ}, title = {Kin grouping is insufficient to explain the inclusive fitness gains of conspecific brood parasitism in the common eider.}, journal = {Molecular ecology}, volume = {28}, number = {21}, pages = {4825-4838}, doi = {10.1111/mec.15258}, pmid = {31578780}, issn = {1365-294X}, mesh = {Animals ; Aquatic Organisms/genetics/parasitology ; Canada ; Ducks/genetics/*parasitology ; Female ; Genotype ; Host-Parasite Interactions/*genetics ; Nesting Behavior/physiology ; Reproduction/genetics ; Symbiosis/*genetics ; }, abstract = {Conspecific brood parasitism allows females to exploit other females' nests and enhance their reproductive output. Here, we test a recent theoretical model of how host females gain inclusive fitness from brood parasitism. High levels of relatedness between host and parasitizer can be maintained either by: (a) kin recognizing and parasitizing each other as a form of cooperative breeding or (b) natal philopatry and nest site fidelity facilitating the formation of kin groups, thereby increasing the probability of parasitism between relatives nesting in close proximity. To address these two hypotheses we genotyped feathers and hatch membranes of common eiders (Somateria mollissima) from western Hudson Bay, Canada, using a noninvasive sampling methodology. We found that most instances of brood parasitism do result in inclusive fitness gains. Furthermore, females with failed nests moved an average of 492 m from their previous year's nest site, while successful females only moved an average of 13 m. Therefore, we observed host-parasite relatedness can occur at levels higher than would be expected by chance even in the absence of kin grouping, suggesting that closely related females nesting near one another is not essential to maintain high host-parasitizer relatedness. In addition, kin grouping is only a transient phenomenon that cannot occur every year due to the propensity for females of failed nests to nest farther away from their nest site in subsequent years than females with successful nests, which provides support for kin recognition as a more likely mechanism to maintain high host-parasitizer relatedness over time.}, } @article {pmid31548861, year = {2019}, author = {Fréville, H and Roumet, P and Rode, NO and Rocher, A and Latreille, M and Muller, MH and David, J}, title = {Preferential helping to relatives: A potential mechanism responsible for lower yield of crop variety mixtures?.}, journal = {Evolutionary applications}, volume = {12}, number = {9}, pages = {1837-1849}, pmid = {31548861}, issn = {1752-4571}, abstract = {Variety mixtures, the cultivation of different genotypes within a field, have been proposed as a way to increase within-crop diversity, allowing the development of more sustainable agricultural systems with reduced environmental costs. Although mixtures have often been shown to over-yield the average of component varieties in pure stands, decreased yields in mixtures have also been documented. Kin selection may explain such pattern, whenever plants direct helping behaviors preferentially toward relatives and thus experience stronger competition when grown with less related neighbors, lowering seed production of mixtures. Using varieties of durum wheat originating from traditional Moroccan agrosystems, we designed a greenhouse experiment to address whether plants reduced competition for light by limiting stem elongation when growing with kin and whether such phenotypic response resulted in higher yield of kin groups. Seeds were sown in groups of siblings and nonkin, each group containing a focal plant surrounded by four neighbors. At the group level, mean plant height and yield did not depend upon relatedness among competing plants. At the individual level, plant height was not affected by genetic relatedness to neighbors, after accounting for direct genetic effects that might induce among-genotype differences in the ability to capture resources that do not depend on relatedness. Moreover, in contrast to our predictions, shorter plants had lower inclusive fitness. Phenotypic plasticity in height was very limited in response to neighbor genotypes. This suggests that human selection in crops may have attenuated shade-avoidance responses to competition for light. Future research on preferential helping to relatives in crops might thus target social traits that drive competition for other resources than light. Overall, our study illustrates the relevance of tackling agricultural issues from an evolutionary standpoint and calls for extending such approaches to a larger set of crop species.}, } @article {pmid31533478, year = {2019}, author = {Tanskanen, AO and Danielsbacka, M and Coall, DA and Jokela, M}, title = {Transition to Grandparenthood and Subjective Well-Being in Older Europeans: A Within-Person Investigation Using Longitudinal Data.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {17}, number = {3}, pages = {1474704919875948}, pmid = {31533478}, issn = {1474-7049}, support = {HHSN271201300071C/AG/NIA NIH HHS/United States ; }, mesh = {Aged ; Europe ; Female ; Grandparents/*psychology ; Humans ; *Intergenerational Relations ; Longitudinal Studies ; Male ; Middle Aged ; *Personal Satisfaction ; Quality of Life/*psychology ; }, abstract = {The transition to grandparenthood, that is the birth of the first grandchild, is often assumed to increase the subjective well-being of older adults; however, prior studies are scarce and have provided mixed results. Investigation of the associations between grandparenthood and subjective well-being, measured by self-rated life satisfaction, quality of life scores, and depressive symptoms, used the longitudinal Survey of Health, Ageing and Retirement in Europe from 13 countries, including follow-up waves between 2006 and 2015 (n = 64,940 person-observations from 38,456 unique persons of whom 18,207 had two or more measurement times). Both between-person and within-person (or fixed-effect) regression models were executed, where between-person associations represent results across individuals, that is, between grandparents and non-grandparents; within-person associations represent an individual's variation over time, that is, they consider whether the transition to grandparenthood increases or decreases subjective well-being. According to the between-person models, both grandmothers and grandfathers reported higher rate of life satisfaction and quality of life than non-grandparents. Moreover, grandmothers reported fewer depressive symptoms than women without grandchildren. The within-person models indicated that entry into grandmotherhood was associated with both improved quality of life scores and improved life satisfaction. These findings are discussed with reference to inclusive fitness theory, parental investment theory, and the grandmother hypothesis.}, } @article {pmid31522939, year = {2019}, author = {Kalske, A and Shiojiri, K and Uesugi, A and Sakata, Y and Morrell, K and Kessler, A}, title = {Insect Herbivory Selects for Volatile-Mediated Plant-Plant Communication.}, journal = {Current biology : CB}, volume = {29}, number = {18}, pages = {3128-3133.e3}, doi = {10.1016/j.cub.2019.08.011}, pmid = {31522939}, issn = {1879-0445}, mesh = {Animals ; Cues ; Genotype ; Herbivory/*physiology ; Insecta/physiology ; Pheromones/metabolism/*physiology ; Plants/*chemistry/metabolism ; Solidago/metabolism ; Volatile Organic Compounds/chemistry ; }, abstract = {Plant volatile organic compounds (VOCs) are major vehicles of information transfer between organisms and mediate many ecological interactions [1-3]. Altering VOC emission in response to herbivore damage has been hypothesized to be adaptive, as it can deter subsequent herbivores [4], attract natural enemies of herbivores [5], or transmit information about attacks between distant parts of the same plant [6-9]. Neighboring plants may also respond to these VOC cues by priming their own defenses against oncoming herbivory, thereby reducing future damage [10-12]. However, under which conditions such information sharing provides fitness benefits to emitter plants, and, therefore, whether selection by herbivores affects the evolution of such VOC signaling, is still unclear [13]. Here, we test the predictions of two alternative hypotheses, the kin selection and mutual benefits hypotheses [14], to uncover the selective environment that may favor information sharing in plants. Measuring the response to natural selection in Solidago altissima, we found strong effects of herbivory on the way plants communicated with neighbors. Plants from populations that experienced selection by insect herbivory induced resistance in all neighboring conspecifics by airborne cues, whereas those from populations experiencing herbivore exclusion induced resistance only in neighbors of the same genotype. Furthermore, the information-sharing plants converged on a common, airborne VOC signal upon damage. We demonstrate that herbivory can drive the evolution of plant-plant communication via induction of airborne cues and suggest plants as a model system for understanding information sharing and communication among organisms in general.}, } @article {pmid31506055, year = {2019}, author = {Berg, EC and Lind, MI and Monahan, S and Bricout, S and Maklakov, AA}, title = {Kin but less than kind: within-group male relatedness does not increase female fitness in seed beetles.}, journal = {Proceedings. Biological sciences}, volume = {286}, number = {1910}, pages = {20191664}, pmid = {31506055}, issn = {1471-2954}, mesh = {Animals ; Coleoptera/*physiology ; Female ; Male ; Reproduction ; *Sexual Behavior, Animal ; }, abstract = {Theory maintains within-group male relatedness can mediate sexual conflict by reducing male-male competition and collateral harm to females. We tested whether male relatedness can lessen female harm in the seed beetle Callosobruchus maculatus. Male relatedness did not influence female lifetime reproductive success or individual fitness across two different ecologically relevant scenarios of mating competition. However, male relatedness marginally improved female survival. Because male relatedness improved female survival in late life when C. maculatus females are no longer producing offspring, our results do not provide support for the role of within-group male relatedness in mediating sexual conflict. The fact that male relatedness improves the post-reproductive part of the female life cycle strongly suggests that the effect is non-adaptive. We discuss adaptive and non-adaptive mechanisms that could result in reduced female harm in this and previous studies, and suggest that cognitive error is a likely explanation.}, } @article {pmid31490727, year = {2019}, author = {Smith, AL and Atwater, DZ and Callaway, RM}, title = {Early Sibling Conflict May Ultimately Benefit the Family.}, journal = {The American naturalist}, volume = {194}, number = {4}, pages = {482-487}, doi = {10.1086/704773}, pmid = {31490727}, issn = {1537-5323}, mesh = {Aegilops/*growth & development/physiology ; Fertilizers ; Seedlings/*growth & development/physiology ; Seeds ; Soil ; }, abstract = {Relatives often interact differently with each other than with nonrelatives, and whether kin cooperate or compete has important consequences for the evolution of mating systems, seed size, dispersal, and competition. Previous research found that the larger of the size dimorphic seeds produced by the annual plant Aegilops triuncialis suppressed germination of their smaller sibs by 25%-60%. Here, we found evidence for kin recognition and sibling rivalry later in life among Aegilops seedlings that places seed-seed interactions in a broader context. In experiments with size dimorphic seeds, seedlings reduced the growth of sibling seedlings by ∼40% but that of nonsibling seedlings by ∼25%. These sequential antagonistic interactions between seeds and then seedlings provide insight into conflict and cooperation among kin. Kin-based conflict among seeds may maintain dormancy for some seeds until the coast is clear of more competitive siblings. If so, biotically induced seed dormancy may be a unique form of cooperation, which increases the inclusive fitness of maternal plants and offspring by minimizing competition among kin.}, } @article {pmid31488327, year = {2019}, author = {Madgwick, PG and Belcher, LJ and Wolf, JB}, title = {Greenbeard Genes: Theory and Reality.}, journal = {Trends in ecology & evolution}, volume = {34}, number = {12}, pages = {1092-1103}, doi = {10.1016/j.tree.2019.08.001}, pmid = {31488327}, issn = {1872-8383}, support = {BB/M01035X/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Altruism ; *Biological Evolution ; Cooperative Behavior ; }, abstract = {Greenbeard genes were proposed as a cartoonish thought experiment to explain why altruism can be a selfish strategy from the perspective of genes. The likelihood of finding a real greenbeard gene in nature was thought to be remote because they were believed to require a set of improbable properties. Yet, despite this expectation, there is an ongoing explosion in claimed discoveries of greenbeard genes. Bringing together the latest theory and experimental findings, we argue that there is a need to dispose of the cartoon presentation of a greenbeard to refocus their burgeoning empirical study on the more fundamental concept that the thought experiment was designed to illustrate.}, } @article {pmid31474495, year = {2019}, author = {Martens, J}, title = {Hamilton meets causal decision theory.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {77}, number = {}, pages = {101187}, doi = {10.1016/j.shpsc.2019.101187}, pmid = {31474495}, issn = {1879-2499}, mesh = {*Altruism ; *Biological Evolution ; *Decision Theory ; *Genetic Fitness ; Models, Biological ; }, abstract = {In this paper, I contrast two mathematically equivalent ways of modeling the evolution of altruism, namely the classical inclusive fitness approach and a more recent, "direct fitness" approach. Though both are usually considered by evolutionists as mere different ways of representing the same causal process (i.e. that of kin selection), I argue that this consensus is misleading, for there is a fundamental ambiguity concerning the causal interpretation of the DF approach. Drawing on an analogy between the structure of inclusive fitness theory and that of causal decision theory (Stalnaker, 1972), I show that only the inclusive fitness framework can provide us with a proper, and unambiguous causal partition of the relevant variables involved in the evolution of altruism.}, } @article {pmid31463010, year = {2019}, author = {Vostinar, AE and Goldsby, HJ and Ofria, C}, title = {Suicidal selection: Programmed cell death can evolve in unicellular organisms due solely to kin selection.}, journal = {Ecology and evolution}, volume = {9}, number = {16}, pages = {9129-9136}, pmid = {31463010}, issn = {2045-7758}, abstract = {ABSTRACT: Unicellular organisms can engage in a process by which a cell purposefully destroys itself, termed programmed cell death (PCD). While it is clear that the death of specific cells within a multicellular organism could increase inclusive fitness (e.g., during development), the origin of PCD in unicellular organisms is less obvious. Kin selection has been shown to help maintain instances of PCD in existing populations of unicellular organisms; however, competing hypotheses exist about whether additional factors are necessary to explain its origin. Those factors could include an environmental shift that causes latent PCD to be expressed, PCD hitchhiking on a large beneficial mutation, and PCD being simply a common pathology. Here, we present results using an artificial life model to demonstrate that kin selection can, in fact, be sufficient to give rise to PCD in unicellular organisms. Furthermore, when benefits to kin are direct-that is, resources provided to nearby kin-PCD is more beneficial than when benefits are indirect-that is, nonkin are injured, thus increasing the relative amount of resources for kin. Finally, when considering how strict organisms are in determining kin or nonkin (in terms of mutations), direct benefits are viable in a narrower range than indirect benefits.

OPEN RESEARCH BADGES: This article has been awarded Open Data and Open Materials Badges. All materials and data are publicly accessible via the Open Science Framework at https://github.com/anyaevostinar/SuicidalAltruismDissertation/tree/master/LongTerm.}, } @article {pmid31454451, year = {2019}, author = {Khodaei, L and Long, TAF}, title = {Kin recognition and co-operative foraging in Drosophila melanogaster larvae.}, journal = {Journal of evolutionary biology}, volume = {32}, number = {12}, pages = {1352-1361}, doi = {10.1111/jeb.13531}, pmid = {31454451}, issn = {1420-9101}, mesh = {Animals ; Behavior, Animal/physiology ; *Cooperative Behavior ; Drosophila melanogaster/*physiology ; Female ; Larva/physiology ; Male ; }, abstract = {A long-standing goal for biologists and social scientists is to understand the factors that lead to the evolution and maintenance of co-operative behaviour between conspecifics. To that end, the fruit fly, Drosophila melanogaster, is becoming an increasingly popular model species to study sociality; however, most of the research to date has focused on adult behaviours. In this study, we set out to examine group-feeding behaviour by larvae and to determine whether the degree of relatedness between individuals mediates the expression co-operation. In a series of assays, we manipulated the average degree of relatedness in groups of third-instar larvae that were faced with resource scarcity, and measured the size, frequency and composition of feeding clusters, as well as the fitness benefits associated with co-operation. Our results suggest that larval D. melanogaster are capable of kin recognition (something that has not been previously described in this species), as clusters were more numerous, larger and involved more larvae, when more closely related kin were present in the social environment. These findings are discussed in the context of the correlated fitness-associated benefits of co-operation, the potential mechanisms by which individuals may recognize kin, and how that kinship may play an important role in facilitating the manifestation of this co-operative behaviour.}, } @article {pmid31422471, year = {2019}, author = {Cayuela, H and Boualit, L and Laporte, M and Prunier, JG and Preiss, F and Laurent, A and Foletti, F and Clobert, J and Jacob, G}, title = {Kin-dependent dispersal influences relatedness and genetic structuring in a lek system.}, journal = {Oecologia}, volume = {191}, number = {1}, pages = {97-112}, pmid = {31422471}, issn = {1432-1939}, mesh = {Animals ; Birds ; *Breeding ; Female ; France ; Male ; *Microsatellite Repeats ; }, abstract = {Kin selection and dispersal play a critical role in the evolution of cooperative breeding systems. Limited dispersal increases relatedness in spatially structured populations (population viscosity), with the result that neighbours tend to be genealogical relatives. Yet the increase in neighbours' fitness-related performance through altruistic interaction may also result in habitat saturation and thus exacerbate local competition between kin. Our goal was to detect the footprint of kin selection and competition by examining the spatial structure of relatedness and by comparing non-effective and effective dispersal in a population of a lekking bird, Tetrao urogallus. For this purpose, we analysed capture-recapture and genetic data collected over a 6-year period on a spatially structured population of T. urogallus in France. Our findings revealed a strong spatial structure of relatedness in males. They also indicated that the population viscosity could allow male cooperation through two non-exclusive mechanisms. First, at their first lek attendance, males aggregate in a lek composed of relatives. Second, the distance corresponding to non-effective dispersal dramatically outweighed effective dispersal distance, which suggests that dispersers incur high post-settlement costs. These two mechanisms result in strong population genetic structuring in males. In females, our findings revealed a lower level of spatial structure of relatedness and genetic structure in respect to males. Additionally, non-effective dispersal and effective dispersal distances in females were highly similar, which suggests limited post-settlement costs. These results indicate that kin-dependent dispersal decisions and costs have a genetic footprint in wild populations and are factors that may be involved in the evolution of cooperative courtship.}, } @article {pmid31406338, year = {2019}, author = {Page, AE and Thomas, MG and Smith, D and Dyble, M and Viguier, S and Chaudhary, N and Salali, GD and Thompson, J and Mace, R and Migliano, AB}, title = {Testing adaptive hypotheses of alloparenting in Agta foragers.}, journal = {Nature human behaviour}, volume = {3}, number = {11}, pages = {1154-1163}, pmid = {31406338}, issn = {2397-3374}, support = {MR/P014216/1/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Adolescent ; Adult ; Aged ; Anthropology, Cultural ; *Caregivers ; Child ; *Child Care ; Child, Preschool ; Cooperative Behavior ; Family ; Female ; Humans ; Infant ; Male ; Middle Aged ; *Parenting ; *Parents ; Philippines ; Social Behavior ; Young Adult ; }, abstract = {Human children are frequently cared for by non-parental caregivers (alloparents), yet few studies have conducted systematic alternative hypothesis tests of why alloparents help. Here we explore whether predictions from kin selection, reciprocity, learning-to-mother and costly signalling hypotheses explain non-parental childcare among Agta hunter-gatherers from the Philippines. To test these hypotheses, we used high-resolution proximity data from 1,701 child-alloparent dyads. Our results indicated that reciprocity and relatedness were positively associated with the number of interactions with a child (our proxy for childcare). Need appeared more influential in close kin, suggesting indirect benefits, while reciprocity proved to be a stronger influence in non-kin, pointing to direct benefits. However, despite shared genes, close and distant kin interactions were also contingent on reciprocity. Compared with other apes, humans are unique in rapidly producing energetically demanding offspring. Our results suggest that the support that mothers require is met through support based on kinship and reciprocity.}, } @article {pmid31392902, year = {2019}, author = {Schriver, J and Perunovic, WQE and Brymer, K and Hachey, T}, title = {Do Relatives With Greater Reproductive Potential Get Help First?: A Test of the Inclusive Fitness Explanation of Kin Altruism.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {17}, number = {3}, pages = {1474704919867094}, pmid = {31392902}, issn = {1474-7049}, mesh = {Adult ; Aged ; *Altruism ; Emotions/physiology ; Family/*psychology ; Family Relations/*psychology ; Female ; Helping Behavior ; Humans ; Male ; Middle Aged ; Reproduction/*physiology ; Young Adult ; }, abstract = {According to inclusive fitness theory, people are more willing to help those they are genetically related to because relatives share a kin altruism gene and are able to pass it along. We tested this theory by examining the effect of reproductive potential on altruism. Participants read hypothetical scenarios and chose between cousins (Studies 1 and 2) and cousins and friends (Study 3) to help with mundane chores or a life-or-death rescue. In life-or-death situations, participants were more willing to help a cousin preparing to conceive rather than adopt a child (Study 1) and a cousin with high rather than low chance of reproducing (Studies 2 and 3). Patterns in the mundane condition were less consistent. Emotional closeness also contributed to helping intentions (Studies 1 and 2). By experimentally manipulating reproductive potential while controlling for genetic relatedness and emotional closeness, we provide a demonstration of the direct causal effects of reproductive potential on helping intentions, supporting the inclusive fitness explanation of kin altruism.}, } @article {pmid31381581, year = {2019}, author = {Berkowic, D and Markman, S}, title = {Weighing density and kinship: Aggressive behavior and time allocation in fire salamander (Salamandra infraimmaculata).}, journal = {PloS one}, volume = {14}, number = {8}, pages = {e0220499}, pmid = {31381581}, issn = {1932-6203}, mesh = {Aggression ; Animals ; Behavior, Animal ; Cannibalism ; Female ; Larva/physiology ; Population Density ; Salamandra/*physiology ; }, abstract = {Kin-biased behavior (that is responding differentially to kin and non-kin) is thought to be adaptive in many social interactions. One example of this kin bias is behaving less aggressively toward a relative than a non-relative, a behavior which yields inclusive fitness benefits. However, data are lacking about the ability of animals to weigh their preference for kinship and the density of conspecifics simultaneously and to respond accordingly. Fire salamanders (Salamandra infraimmaculata) larviposit in high densities in ponds. Thus, larvae of different females confront competition and predation by other larvae. We studied whether larvae prefer their kin over particular density or vice versa. We experimentally used a transparent glass aquarium with inner chambers to test the responses of a focal larva toward its siblings and non-siblings. Specifically, we quantified the time a focal larva spent near its siblings or non-siblings, presented in varying densities, and the aggression level it demonstrated. We found that focal larvae spent more time near non-siblings if non-sibling and sibling groups were of equal density. The focal larvae were also more aggressive toward non-siblings. The results may be explained by the cannibalistic nature of these larvae: high density may provide more opportunities for food, especially when non-siblings are present. Further explanations for these findings may include other advantages of staying in a larger group and/or the stronger olfactory and visual stimulation offered by groups compared to a single individual. These findings suggest that larvae make differential responses toward conspecifics depending simultaneously on the level of relatedness and the density of the group. Such responses have important implications for social-aggregation decisions and may especially affect the fitness of cannibalistic species.}, } @article {pmid31358195, year = {2019}, author = {Spivak, M and Goblirsch, M and Simone-Finstrom, M}, title = {Social-medication in bees: the line between individual and social regulation.}, journal = {Current opinion in insect science}, volume = {33}, number = {}, pages = {49-55}, doi = {10.1016/j.cois.2019.02.009}, pmid = {31358195}, issn = {2214-5753}, mesh = {Animals ; Bees/microbiology/parasitology/*physiology ; Behavior, Animal ; *Feeding Behavior ; Plants/chemistry ; *Social Behavior ; }, abstract = {We use the term social-medication to describe the deliberate consumption or use of plant compounds by social insects that are detrimental to a pathogen or parasite at the colony level, result in increased inclusive fitness to the colony, and have potential costs either at the individual or colony level in the absence of parasite infection. These criteria for social-medication differ from those for self-medication in that inclusive fitness costs and benefits are distinguished from individual costs and benefits. The consumption of pollen and nectar may be considered a form of social immunity if they help fight infection, resulting in a demonstrated increase in colony health and survival. However, the dietary use of pollen and nectar per se is likely not a form of social-medication unless there is a detriment or cost to their consumption in the absence of parasite infection, such as when they contain phytochemicals that are toxic at certain doses. We provide examples among social bees (bumblebees, stingless bees and honey bees) in which the consumption or use of plant compounds have a demonstrated role in parasite defense and health of the colony. We indicate where more work is needed to distinguish between prophylactic and therapeutic effects of these compounds, and whether the effects are observed at the individual or colony level.}, } @article {pmid31326325, year = {2019}, author = {Birch, J}, title = {Inclusive fitness as a criterion for improvement.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {76}, number = {}, pages = {101186}, doi = {10.1016/j.shpsc.2019.101186}, pmid = {31326325}, issn = {1879-2499}, mesh = {*Biological Evolution ; Biology/*methods ; *Gene Frequency ; *Genetic Fitness ; Models, Genetic ; Philosophy ; }, abstract = {I distinguish two roles for a fitness concept in the context of explaining cumulative adaptive evolution: fitness as a predictor of gene frequency change, and fitness as a criterion for phenotypic improvement. Critics of inclusive fitness argue, correctly, that it is not an ideal fitness concept for the purpose of predicting gene-frequency change, since it relies on assumptions about the causal structure of social interaction that are unlikely to be exactly true in real populations, and that hold as approximations only given a specific type of weak selection. However, Hamilton took this type of weak selection, on independent grounds, to be responsible for cumulative assembly of complex adaptations. In this special context, I argue that inclusive fitness is distinctively valuable as a criterion for improvement and a standard for optimality. Yet to call inclusive fitness a criterion for improvement and a standard for optimality is not to make any claim about the frequency with which inclusive fitness optimization actually occurs in nature. This is an empirical question that cannot be settled by theory alone. I close with some reflections on the place of inclusive fitness in the long running clash between 'causalist' and 'statisticalist' conceptions of fitness.}, } @article {pmid31326324, year = {2019}, author = {Huneman, P}, title = {Revisiting darwinian teleology: A case for inclusive fitness as design explanation.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {76}, number = {}, pages = {101188}, doi = {10.1016/j.shpsc.2019.101188}, pmid = {31326324}, issn = {1879-2499}, mesh = {*Biological Evolution ; Biology/*methods ; *Genetic Fitness ; Models, Genetic ; Philosophy ; }, abstract = {This paper elaborates a general framework to make sense of teleological explanations in Darwinian evolutionary biology. It relies on an attempt to tie natural selection to a sense of optimization. First, after assessing the objections made by any attempt to view selection as a maximising process within population genetics, it understands Grafen's Formal Darwinism (FD) as a conceptual link established between population genetics and behavioral ecology's adaptationist framework (without any empirical commitments). Thus I suggest that this provides a way to make sense of teleological explanations in biology under their various modes. Then the paper criticizes two major ways of accounting for teleology: a Darwinian one, the etiological view of biological functions, and a non-Darwinian one, here labeled "intrinsic teleology" view, which covers several subtypes of accounts, including plasticity-oriented conceptions of evolution or organizational views of function. The former is centered on traits while the latter is centered on organisms; this is shown to imply that both accounts are unable to provide a systematic understanding of biological teleology. Finally the paper argues that viewing teleology as maximization of inclusive fitness along the FD lines as understood here allows one to make sense of both the design of organisms and the individual traits as adaptions. Such notion is thereby claimed to be the proper meaning of teleology in evolutionary biology, since it avoids the opposed pitfalls of etiological views and intrinsic-teleology view, while accounting for the same features as they do.}, } @article {pmid31325322, year = {2019}, author = {Mullon, C and Lehmann, L}, title = {An evolutionary quantitative genetics model for phenotypic (co)variances under limited dispersal, with an application to socially synergistic traits.}, journal = {Evolution; international journal of organic evolution}, volume = {73}, number = {9}, pages = {1695-1728}, doi = {10.1111/evo.13803}, pmid = {31325322}, issn = {1558-5646}, support = {PP00P3-123344//Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung/International ; }, mesh = {Animals ; *Biological Evolution ; Breeding ; Genetic Fitness ; Haploidy ; Humans ; *Models, Genetic ; Multivariate Analysis ; Mutation ; *Phenotype ; Probability ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Darwinian evolution consists of the gradual transformation of heritable traits due to natural selection and the input of random variation by mutation. Here, we use a quantitative genetics approach to investigate the coevolution of multiple quantitative traits under selection, mutation, and limited dispersal. We track the dynamics of trait means and of variance-covariances between traits that experience frequency-dependent selection. Assuming a multivariate-normal trait distribution, we recover classical dynamics of quantitative genetics, as well as stability and evolutionary branching conditions of invasion analyses, except that due to limited dispersal, selection depends on indirect fitness effects and relatedness. In particular, correlational selection that associates different traits within-individuals depends on the fitness effects of such associations between-individuals. We find that these kin selection effects can be as relevant as pleiotropy for the evolution of correlation between traits. We illustrate this with an example of the coevolution of two social traits whose association within-individuals is costly but synergistically beneficial between-individuals. As dispersal becomes limited and relatedness increases, associations between-traits between-individuals become increasingly targeted by correlational selection. Consequently, the trait distribution goes from being bimodal with a negative correlation under panmixia to unimodal with a positive correlation under limited dispersal.}, } @article {pmid31324139, year = {2019}, author = {Garay, J and Garay, BM and Varga, Z and Csiszár, V and Móri, TF}, title = {To save or not to save your family member's life? Evolutionary stability of self-sacrificing life history strategy in monogamous sexual populations.}, journal = {BMC evolutionary biology}, volume = {19}, number = {1}, pages = {147}, pmid = {31324139}, issn = {1471-2148}, mesh = {Animals ; *Biological Evolution ; Genetics, Population ; Genotype ; Humans ; *Life Cycle Stages ; Mutation/genetics ; Phenotype ; *Sexual Behavior ; }, abstract = {BACKGROUND: For the understanding of human nature, the evolutionary roots of human moral behaviour are a key precondition. Our question is as follows: Can the altruistic moral rule "Risk your life to save your family members, if you want them to save your life" be evolutionary stable? There are three research approaches to investigate this problem: kin selection, group selection and population genetics modelling. The present study is strictly based on the last approach.

RESULTS: We consider monogamous and exogamous families, where at an autosomal locus, dominant-recessive alleles determine the phenotypes in a sexual population. Since all individuals' survival rate is determined by their altruistic family members, we introduce a new population genetics model based on the mating table approach and adapt the verbal definition of evolutionary stability to genotypes. In general, when the resident is recessive, a homozygote is an evolutionarily stable genotype (ESG), if the number of survivors of the resident genotype of the resident homozygote family is greater than that of non-resident heterozygote survivors of the family of the resident homozygote and mutant heterozygote genotypes. Using the introduced genotype dynamics we proved that in the recessive case ESG implies local stability of the altruistic genotype. We apply our general ESG conditions for self-sacrificing life history strategy when the number of new-born offspring does not depend on interactions within the family and the interactions are additive. We find that in this case our ESG conditions give back Hamilton's rule for evolutionary stability of the self-sacrificing life history strategy.

CONCLUSIONS: In spite of the fact that the kidney transplantations was not a selection factor during the earlier human evolution, nowadays "self-sacrificing" can be observed in the live donor kidney transplantations, when the donor is one of the family members. It seems that selection for self-sacrificing in family produced an innate moral tendency in modulating social cognition in human brain.}, } @article {pmid31312507, year = {2019}, author = {Woodford, P}, title = {Evaluating inclusive fitness.}, journal = {Royal Society open science}, volume = {6}, number = {6}, pages = {190644}, pmid = {31312507}, issn = {2054-5703}, } @article {pmid31303163, year = {2019}, author = {Koster, J and Lukas, D and Nolin, D and Power, E and Alvergne, A and Mace, R and Ross, CT and Kramer, K and Greaves, R and Caudell, M and MacFarlan, S and Schniter, E and Quinlan, R and Mattison, S and Reynolds, A and Yi-Sum, C and Massengill, E}, title = {Kinship ties across the lifespan in human communities.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1780}, pages = {20180069}, pmid = {31303163}, issn = {1471-2970}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; Child, Preschool ; Emigrants and Immigrants/psychology ; Female ; Humans ; Infant ; *Longevity ; Male ; Middle Aged ; Reproduction ; Residence Characteristics/statistics & numerical data ; *Social Behavior ; Young Adult ; }, abstract = {A hypothesis for the evolution of long post-reproductive lifespans in the human lineage involves asymmetries in relatedness between young immigrant females and the older females in their new groups. In these circumstances, inter-generational reproductive conflicts between younger and older females are predicted to resolve in favour of the younger females, who realize fewer inclusive fitness benefits from ceding reproduction to others. This conceptual model anticipates that immigrants to a community initially have few kin ties to others in the group, gradually showing greater relatedness to group members as they have descendants who remain with them in the group. We examine this prediction in a cross-cultural sample of communities, which vary in their sex-biased dispersal patterns and other aspects of social organization. Drawing on genealogical and demographic data, the analysis provides general but not comprehensive support for the prediction that average relatedness of immigrants to other group members increases as they age. In rare cases, natal members of the community also exhibit age-related increases in relatedness. We also find large variation in the proportion of female group members who are immigrants, beyond simple traditional considerations of patrilocality or matrilocality, which raises questions about the circumstances under which this hypothesis of female competition are met. We consider possible explanations for these heterogenous results, and we address methodological considerations that merit increased attention for research on kinship and reproductive conflict in human societies. This article is part of the theme issue 'The evolution of female-biased kinship in humans and other mammals'.}, } @article {pmid31303162, year = {2019}, author = {Lynch, EC and Lummaa, V and Htut, W and Lahdenperä, M}, title = {Evolutionary significance of maternal kinship in a long-lived mammal.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1780}, pages = {20180067}, pmid = {31303162}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; Elephants/genetics/*physiology ; Family ; Female ; Male ; Reproduction ; Social Behavior ; }, abstract = {Preferential treatment of kin is widespread across social species and is considered a central prerequisite to the evolution of cooperation through kin selection. Though it is well known that, among most social mammals, females will remain within their natal group and often bias social behaviour towards female maternal kin, less is known about the fitness consequences of these relationships. We test the fitness benefits of living with maternal sisters, measured by age-specific female reproduction, using an unusually large database of a semi-captive Asian elephant (Elephas maximus) population. This study system is particularly valuable to an exploration of reproductive trends in a long-lived mammal, because it includes life-history data that span multiple generations, enabling a study of the effects of kinship across a female's lifespan. We find that living near a sister significantly increased the likelihood of annual reproduction among young female elephants, and this effect was strongest when living near a sister 0-5 years younger. Our results show that fitness benefits gained from relationships with kin are age-specific, establish the basis necessary for the formation and maintenance of close social relationships with female kin, and highlight the adaptive importance of matriliny in a long-lived mammal. This article is part of the theme issue 'The evolution of female-biased kinship in humans and other mammals'.}, } @article {pmid31303158, year = {2019}, author = {Holekamp, KE and Sawdy, MA}, title = {The evolution of matrilineal social systems in fissiped carnivores.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1780}, pages = {20180065}, pmid = {31303158}, issn = {1471-2970}, mesh = {Animals ; Behavior, Animal ; *Biological Evolution ; Carnivora/genetics/*physiology ; Female ; Hyaenidae/genetics/*physiology ; Lions/genetics/*physiology ; Male ; *Social Behavior ; }, abstract = {We review matrilineal relationships in the societies of fissiped mammalian carnivores, focusing on how the most complex of these may have evolved from simpler systems. Although competition for food is very intense at the trophic level occupied by most carnivores, and although most species of extant fissiped carnivores therefore lead solitary lives, some species show at least rudimentary clustering of maternal kin and matrilineal resource-sharing or transmission of critical resources between generations. The resources shared or transmitted range from individual food items and territories to entire networks of potential allies. The greatest elaboration of matrilineal relationships has occurred in two large carnivores, lions and spotted hyenas, which occur sympatrically throughout much of Africa. The societies of both these species apparently evolved in response to a shared suite of ecological conditions. The highly matrilineal societies of spotted hyenas are unique among carnivores and closely resemble the societies of many cercopithecine primates. The conditions favouring the evolution of matrilineal societies in carnivores include male-biased dispersal, female philopatry, the need for assistance in protecting or provisioning offspring, reliance on large or abundant prey, particularly in open habitat, high population density and kin-structured cooperative interactions that have strong positive effects on fitness. This article is part of the theme issue 'The evolution of female-biased kinship in humans and other mammals'.}, } @article {pmid31289691, year = {2019}, author = {Ross, L and Davies, NG and Gardner, A}, title = {How to make a haploid male.}, journal = {Evolution letters}, volume = {3}, number = {2}, pages = {173-184}, pmid = {31289691}, issn = {2056-3744}, abstract = {Haplodiploidy has evolved repeatedly among invertebrates, and appears to be associated with inbreeding. Evolutionary biologists have long debated the possible benefits for females in diplodiploid species to produce haploid sons-beginning their population's transition to haplodiploidy-and whether inbreeding promotes or inhibits this transition. However, little attention has been given to what makes a haploid individual male rather than female, and whether the mechanism of sex determination may modulate the costs and benefits of male haploidy. We remedy this by performing a theoretical analysis of the origin and invasion of male haploidy across the full range of sex-determination mechanisms and sib-mating rates. We find that male haploidy is facilitated by three different mechanisms of sex determination-all involving male heterogamety-and impeded by the others. We also find that inbreeding does not pose an obvious evolutionary barrier, on account of a previously neglected sex-ratio effect whereby the production of haploid sons leads to an abundance of granddaughters that is advantageous in the context of inbreeding. We find empirical support for these predictions in a survey of sex determination and inbreeding across haplodiploids and their sister taxa.}, } @article {pmid31272291, year = {2020}, author = {Ng, YL}, title = {Active and Passive Facebook Use and Associated Costly Off-line Helping Behavior.}, journal = {Psychological reports}, volume = {123}, number = {6}, pages = {2562-2581}, doi = {10.1177/0033294119860262}, pmid = {31272291}, issn = {1558-691X}, mesh = {Adolescent ; Adult ; Aged ; *Altruism ; Female ; Friends/psychology ; *Helping Behavior ; Humans ; Male ; Middle Aged ; Social Media/*statistics & numerical data ; Young Adult ; }, abstract = {This study examined active and passive Facebook use and the associated costly altruistic behavior. Results supported the hypothesis that social media use, particularly active use, can enhance the perceived relatedness of individuals in need and reduce the influence of genetic relatedness in helping. Passive social media users tended to help kin in both situations involving low and high biological cost, whereas they were less likely to risk themselves to help social media friends and strangers in extraordinary situations involving high biological cost. However, active social media users, who had a broader sense of connectedness with genetically unrelated individuals, were more willing to help social media friends and strangers in both situations involving high and low biological cost.}, } @article {pmid31271473, year = {2019}, author = {Leeks, A and Dos Santos, M and West, SA}, title = {Transmission, relatedness, and the evolution of cooperative symbionts.}, journal = {Journal of evolutionary biology}, volume = {32}, number = {10}, pages = {1036-1045}, pmid = {31271473}, issn = {1420-9101}, support = {BB/M011224/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Biological Evolution ; Computer Simulation ; *Models, Biological ; Symbiosis/*genetics ; }, abstract = {Cooperative interactions between species, termed mutualisms, play a key role in shaping natural ecosystems, economically important agricultural systems, and in influencing human health. Across different mutualisms, there is significant variation in the benefit that hosts receive from their symbionts. Empirical data suggest that transmission mode can help explain this variation: vertical transmission, where symbionts infect their host's offspring, leads to symbionts that provide greater benefits to their hosts than horizontal transmission, where symbionts leave their host and infect other hosts in the population. However, two different theoretical explanations have been given for this pattern: firstly, vertical transmission aligns the fitness interests of hosts and their symbionts; secondly, vertical transmission leads to increased relatedness between symbionts sharing a host, favouring cooperation between symbionts. We used a combination of analytical models and dynamic simulations to tease these factors apart, in order to compare their separate influences and see how they interact. We found that relatedness between symbionts sharing a host, rather than transmission mode per se, was the most important factor driving symbiont cooperation. Transmission mode mattered mainly because it determined relatedness. We also found evolutionary branching throughout much of our simulation, suggesting that a combination of transmission mode and multiplicity of infections could lead to the stable coexistence of different symbiont strategies.}, } @article {pmid31247419, year = {2019}, author = {Bourke, AF}, title = {Inclusive fitness and the major transitions in evolution.}, journal = {Current opinion in insect science}, volume = {34}, number = {}, pages = {61-67}, doi = {10.1016/j.cois.2019.03.008}, pmid = {31247419}, issn = {2214-5753}, mesh = {Animals ; *Biological Evolution ; *Genetic Fitness ; }, abstract = {Inclusive fitness theory is the leading framework for explaining the major transitions in evolution, whereby free-living subunits (e.g. cells, organisms) have cooperated to form new, higher-level units (e.g. organisms, eusocial societies). The theory has attracted considerable controversy. From a brief survey of the controversy's present status, I conclude that inclusive fitness theory continues to provide both a concept and a principled modelling tool of value for understanding social evolution, including major transitions. Turning to new developments in the study of major transitions, I describe work defining the point of occurrence of major transitions and, from inclusive fitness theory, the required conditions. I also suggest that it remains important to understand the evolution of individuality that occurs beyond such thresholds.}, } @article {pmid31185857, year = {2019}, author = {Fromhage, L and Jennions, MD}, title = {The strategic reference gene: an organismal theory of inclusive fitness.}, journal = {Proceedings. Biological sciences}, volume = {286}, number = {1904}, pages = {20190459}, pmid = {31185857}, issn = {1471-2954}, mesh = {*Biological Evolution ; Genetic Fitness ; Models, Genetic ; Phenotype ; Reproduction ; Selection, Genetic/*genetics ; }, abstract = {How to define and use the concept of inclusive fitness is a contentious topic in evolutionary theory. Inclusive fitness can be used to calculate selection on a focal gene, but it is also applied to whole organisms. Individuals are then predicted to appear designed as if to maximize their inclusive fitness, provided that certain conditions are met (formally when interactions between individuals are 'additive'). Here we argue that applying the concept of inclusive fitness to organisms is justified under far broader conditions than previously shown, but only if it is appropriately defined. Specifically, we propose that organisms should maximize the sum of their offspring (including any accrued due to the behaviour/phenotype of relatives), plus any effects on their relatives' offspring production, weighted by relatedness. By contrast, most theoreticians have argued that a focal individual's inclusive fitness should exclude any offspring accrued due to the behaviour of relatives. Our approach is based on the notion that long-term evolution follows the genome's 'majority interest' of building coherent bodies that are efficient 'vehicles' for gene propagation. A gene favoured by selection that reduces the propagation of unlinked genes at other loci (e.g. meiotic segregation distorters that lower sperm production) is eventually neutralized by counter-selection throughout the rest of the genome. Most phenotypes will therefore appear as if designed to maximize the propagation of any given gene in a focal individual and its relatives.}, } @article {pmid31171982, year = {2019}, author = {Rautiala, P and Helanterä, H and Puurtinen, M}, title = {Extended haplodiploidy hypothesis.}, journal = {Evolution letters}, volume = {3}, number = {3}, pages = {263-270}, pmid = {31171982}, issn = {2056-3744}, abstract = {Evolution of altruistic behavior was a hurdle for the logic of Darwinian evolution. Soon after Hamilton formalized the concept of inclusive fitness, which explains how altruism can evolve, he suggested that the high sororal relatedness brought by haplodiploidy could be why Hymenopterans have a high prevalence in eusocial species, and why helpers in Hymenoptera are always female. Later it was noted that in order to capitalize on the high sororal relatedness, helpers would need to direct help toward sisters, and this would bias the population sex ratio. Under a 1:3 males:females sex ratio, the inclusive fitness valuation a female places on her sister, brother, and an own offspring are equal-apparently removing the benefit of helping over independent reproduction. Based on this argumentation, haplodiploidy hypothesis has been considered a red herring. However, here we show that when population sex ratio, cost of altruism, and population growth rate are considered together, haplodiploidy does promote female helping even with female-biased sex ratio, due the lowered cost of altruism in such populations. Our analysis highlights the need to re-evaluate the role of haplodiploidy in the evolution of helping, and the importance of fully exploring the model assumptions when comparing interactions of population sex ratios and social behaviors.}, } @article {pmid31164060, year = {2019}, author = {Lenárt, P and Zlámal, F and Kukla, L and Jarkovský, J and Bienertová-Vašků, J}, title = {Sibling relatedness rather than father absence predicts earlier age at menarche in ELSPAC cohort.}, journal = {Biology letters}, volume = {15}, number = {6}, pages = {20190091}, pmid = {31164060}, issn = {1744-957X}, support = {G9815508/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Age Factors ; Child ; *Fathers ; Female ; Humans ; Longitudinal Studies ; Male ; *Menarche ; Pregnancy ; Siblings ; }, abstract = {Many studies during the past 50 years have found an association between father absence and earlier menarche. In connection with these findings, several evolutionary theories assume that father absence is a causal factor accelerating reproductive development. However, a recent study analysing data from the Avon Longitudinal Study of Parents and Children (ALSPAC) found that father absence does not predict age at menarche when adjusted for sibling relatedness. In this study, we have replicated these results in the Czech section of the European Longitudinal Study of Pregnancy and Childhood (ELSPAC), which used the same questionnaires as ALSPAC to study a geographically distinct population. Our results support the conclusion that sibling relatedness rather than father absence predicts age at menarche. Furthermore, our results show that age at menarche in 1990s UK and Czech cohorts is very similar despite socioeconomic differences between the two countries.}, } @article {pmid31163162, year = {2019}, author = {Ostrowski, EA}, title = {Enforcing Cooperation in the Social Amoebae.}, journal = {Current biology : CB}, volume = {29}, number = {11}, pages = {R474-R484}, doi = {10.1016/j.cub.2019.04.022}, pmid = {31163162}, issn = {1879-0445}, mesh = {*Biological Evolution ; Dictyostelium/*physiology ; *Microbial Interactions ; }, abstract = {Cooperation has been essential to the evolution of biological complexity, but many societies struggle to overcome internal conflicts and divisions. Dictyostelium discoideum, or the social amoeba, has been a useful model system for exploring these conflicts and how they can be resolved. When starved, these cells communicate, gather into groups, and build themselves into a multicellular fruiting body. Some cells altruistically die to form the rigid stalk, while the remainder sit atop the stalk, become spores, and disperse. Evolutionary theory predicts that conflict will arise over which cells die to form the stalk and which cells become spores and survive. The power of the social amoeba lies in the ability to explore how cooperation and conflict work across multiple levels, ranging from proximate mechanisms (how does it work?) to ultimate evolutionary answers (why does it work?). Recent studies point to solutions to the problem of ensuring fairness, such as the ability to suppress selfishness and to recognize and avoid unrelated individuals. This work confirms a central role for kin selection, but also suggests new explanations for how social amoebae might enforce cooperation. New approaches based on genomics are also enabling researchers to decipher for the first time the evolutionary history of cooperation and conflict and to determine its role in shaping the biology of multicellular organisms.}, } @article {pmid31163155, year = {2019}, author = {Apicella, CL and Silk, JB}, title = {The evolution of human cooperation.}, journal = {Current biology : CB}, volume = {29}, number = {11}, pages = {R447-R450}, doi = {10.1016/j.cub.2019.03.036}, pmid = {31163155}, issn = {1879-0445}, mesh = {*Altruism ; *Biological Evolution ; *Cooperative Behavior ; Humans ; }, abstract = {Darwin viewed cooperation as a perplexing challenge to his theory of natural selection. Natural selection generally favors the evolution of behaviors that enhance the fitness of individuals. Cooperative behavior, which increases the fitness of a recipient at the expense of the donor, contradicts this logic. William D. Hamilton helped to solve the puzzle when he showed that cooperation can evolve if cooperators direct benefits selectively to other cooperators (i.e. assortment). Kinship, group selection and the previous behavior of social partners all provide mechanisms for assortment (Figure 1), and kin selection and reciprocal altruism are the foundation of the kinds of cooperative behavior observed in many animals. Humans also bias cooperation in favor of kin and reciprocating partners, but the scope, scale, and variability of human cooperation greatly exceed that of other animals. Here, we introduce derived features of human cooperation in the context in which they originally evolved, and discuss the processes that may have shaped the evolution of our remarkable capacity for cooperation. We argue that culturally-evolved norms that specify how people should behave provide an evolutionarily novel mechanism for assortment, and play an important role in sustaining derived properties of cooperation in human groups.}, } @article {pmid31163153, year = {2019}, author = {Kay, T and Lehmann, L and Keller, L}, title = {Kin selection and altruism.}, journal = {Current biology : CB}, volume = {29}, number = {11}, pages = {R438-R442}, doi = {10.1016/j.cub.2019.01.067}, pmid = {31163153}, issn = {1879-0445}, mesh = {*Alleles ; *Altruism ; *Biological Evolution ; *Genetic Fitness ; *Selection, Genetic ; Social Behavior ; }, abstract = {Natural selection is predicated on the 'struggle for existence': life is short, cruel and, whether through predation, disease or starvation, often ends traumatically. It would seem that in such a dog-eat-dog world, organisms ought to act selfishly, and avoid reducing their fitness (expected survival and reproductive success) by expending time and energy helping others. Put another way, alleles that increase the probability of altruism - a behavior whose expression increases the fitness of recipients while decreasing that of the actor - should decrease in frequency across generations and ultimately disappear.}, } @article {pmid31163152, year = {2019}, author = {Birch, J}, title = {Are kin and group selection rivals or friends?.}, journal = {Current biology : CB}, volume = {29}, number = {11}, pages = {R433-R438}, doi = {10.1016/j.cub.2019.01.065}, pmid = {31163152}, issn = {1879-0445}, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Selection, Genetic ; }, abstract = {Kin selection and group selection were once seen as competing explanatory hypotheses but now tend to be seen as equivalent ways of describing the same basic idea. Yet this 'equivalence thesis' seems not to have brought proponents of kin selection and group selection any closer together. This may be because the equivalence thesis merely shows the equivalence of two statistical formalisms without saying anything about causality. W.D. Hamilton was the first to derive an equivalence result of this type. Yet Hamilton was aware of its limitations, and saw that, while illuminating, it papered over some biologically important distinctions. Attending to these distinctions leads to the concept of 'K-G space', which helps us see where the biological disagreements between proponents of kin selection and group selection really lie.}, } @article {pmid31141235, year = {2019}, author = {Southon, RJ and Bell, EF and Graystock, P and Wyatt, CDR and Radford, AN and Sumner, S}, title = {High indirect fitness benefits for helpers across the nesting cycle in the tropical paper wasp Polistes canadensis.}, journal = {Molecular ecology}, volume = {28}, number = {13}, pages = {3271-3284}, doi = {10.1111/mec.15137}, pmid = {31141235}, issn = {1365-294X}, mesh = {Animals ; Female ; *Genetic Fitness ; Genetic Markers ; Genotype ; *Helping Behavior ; Male ; Microsatellite Repeats ; *Nesting Behavior ; Panama ; Polymorphism, Single Nucleotide ; Reproduction ; Wasps/genetics/*physiology ; }, abstract = {Explaining the evolution of helping behaviour in the eusocial insects where nonreproductive ("worker") individuals help raise the offspring of other individuals ("queens") remains one of the most perplexing phenomena in the natural world. Polistes paper wasps are popular study models, as workers retain the ability to reproduce: such totipotency is likely representative of the early stages of social evolution. Polistes is thought to have originated in the tropics, where seasonal constraints on reproductive options are weak and social groups are effectively perennial. Yet, most Polistes research has focused on nontropical species, where seasonality causes family groups to disperse; cofoundresses forming new nests the following spring are often unrelated, leading to the suggestion that direct fitness through nest inheritance is key in the evolution of helping behaviour. Here, we present the first comprehensive genetic study of social structure across the perennial nesting cycle of a tropical Polistes-Polistes canadensis. Using both microsatellites and newly developed single nucleotide polymorphism markers, we show that adult cofoundresses are highly related and that brood production is monopolized by a single female across the nesting cycle. Nonreproductive cofoundresses in tropical Polistes therefore have the potential to gain high indirect fitness benefits as helpers from the outset of group formation, and these benefits persist through the nesting cycle. Direct fitness may have been less important in the origin of Polistes sociality than previously suggested. These findings stress the importance of studying a range of species with diverse life history and ecologies when considering the evolution of reproductive strategies.}, } @article {pmid31132171, year = {2019}, author = {Hitchcock, TJ and Paracchini, S and Gardner, A}, title = {Genomic Imprinting As a Window into Human Language Evolution.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {41}, number = {6}, pages = {e1800212}, doi = {10.1002/bies.201800212}, pmid = {31132171}, issn = {1521-1878}, mesh = {Adaptation, Physiological/genetics ; Altruism ; *Biological Evolution ; Ethics ; Genetic Loci ; Genomic Imprinting/*genetics ; Humans ; Interpersonal Relations ; *Language ; Models, Genetic ; Models, Theoretical ; Phenotype ; }, abstract = {Humans spend large portions of their time and energy talking to one another, yet it remains unclear whether this activity is primarily selfish or altruistic. Here, it is shown how parent-of-origin specific gene expression-or "genomic imprinting"-may provide an answer to this question. First, it is shown why, regarding language, only altruistic or selfish scenarios are expected. Second, it is pointed out that an individual's maternal-origin and paternal-origin genes may have different evolutionary interests regarding investment into language, and that this intragenomic conflict may drive genomic imprinting which-as the direction of imprint depends upon whether investment into language is relatively selfish or altruistic-may be used to discriminate between these two possibilities. Third, predictions concerning the impact of various mutations and epimutations at imprinted loci on language pathologies are derived. In doing so, a framework is developed that highlights avenues for using intragenomic conflicts to investigate the evolutionary drivers of language.}, } @article {pmid31130904, year = {2019}, author = {Shakhar, K}, title = {The Inclusive Behavioral Immune System.}, journal = {Frontiers in psychology}, volume = {10}, number = {}, pages = {1004}, pmid = {31130904}, issn = {1664-1078}, abstract = {Although living in social groups offers many advantages, it comes at a cost of increased transmissible disease. The behavioral immune system (BIS) is thought to have evolved as a first line of defense against such infections. It acts by minimizing the contact of yet uninfected hosts with potential pathogens. The BIS has been observed in a wide range of animals including insects, amphibians and mammals, but most research has focused on humans where the BIS is guided by complex cognitive and emotional processing. When researchers discuss the evolutionary origin of the BIS, they assess how it raises individual fitness. What would happen though if we shift our attention to the evolutionary unit of selection - the gene? Success would be measured as the change in the gene's prevalence in the entire population, and additional behaviors would come to our attention - those that benefit relatives, i.e., behaviors that raise inclusive fitness. One widely-recognized example of the inclusive BIS is social immunity, which is prevalent among eusocial organisms such as bees and ants. Their colonies engage in a collaborative protective behavior such as grooming and the removal of infected members from the nest. Another example may be sickness behavior, which includes the behavioral, cognitive and emotional symptoms that accompany infection, such as fatigue, and loss of appetite and social interest. My colleague and I recently suggested that sickness behavior has evolved because it reduces the direct and indirect contact between an infected host and its healthy kin - improving inclusive fitness. These additional behaviors are not carried out by the healthy individuals, but rather by whole communities in the first case, and by already infected individuals in the second. Since they step beyond the classical definition of BIS, it may be useful to broaden the term to the inclusive behavioral immune system.}, } @article {pmid31094597, year = {2019}, author = {Duncan, C and Gaynor, D and Clutton-Brock, T and Dyble, M}, title = {The Evolution of Indiscriminate Altruism in a Cooperatively Breeding Mammal.}, journal = {The American naturalist}, volume = {193}, number = {6}, pages = {841-851}, doi = {10.1086/703113}, pmid = {31094597}, issn = {1537-5323}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Carnivora/*genetics/psychology ; *Cooperative Behavior ; Female ; Male ; *Models, Genetic ; }, abstract = {Kin selection theory suggests that altruistic behaviors can increase the fitness of altruists when recipients are genetic relatives. Although selection can favor the ability of organisms to preferentially cooperate with close kin, indiscriminately helping all group mates may yield comparable fitness returns if relatedness within groups is very high. Here, we show that meerkats (Suricata suricatta) are largely indiscriminate altruists who do not alter the amount of help provided to pups or group mates in response to their relatedness to them. We present a model showing that indiscriminate altruism may yield greater fitness payoffs than kin discrimination where most group members are close relatives and errors occur in the estimation of relatedness. The presence of errors in the estimation of relatedness provides a feasible explanation for associations between kin discriminative helping and group relatedness in eusocial and cooperatively breeding animals.}, } @article {pmid31094019, year = {2019}, author = {Jänig, S and Weiß, BM and Birkemeyer, C and Widdig, A}, title = {Comparative chemical analysis of body odor in great apes.}, journal = {American journal of primatology}, volume = {81}, number = {6}, pages = {e22976}, doi = {10.1002/ajp.22976}, pmid = {31094019}, issn = {1098-2345}, support = {WI 1808/3-1//Deutsche Forschungsgemeinschaft/International ; R00061//Universität Leipzig/International ; }, mesh = {Age Factors ; Animals ; Female ; Gas Chromatography-Mass Spectrometry ; Gorilla gorilla/*physiology ; Male ; Odorants/*analysis ; Pan paniscus/*physiology ; Pan troglodytes/*physiology ; Pongo abelii/*physiology ; Sex Factors ; }, abstract = {Olfaction is important across the animal kingdom for transferring information on, for example, species, sex, group membership, or reproductive parameters. Its relevance has been established in primates including humans, yet research on great apes still is fragmentary. Observational evidence indicates that great apes use their sense of smell in various contexts, but the information content of their body odor has not been analyzed. Our aim was therefore to compare the chemical composition of body odor in great ape species, namely Sumatran orangutans (Pongo abelii (Lesson, 1827), one adult male, five adult females, four nonadults), Western lowland gorillas (Gorilla gorilla gorilla (Savage, 1847), one adult male, two adult females, one nonadult), common chimpanzees (Pan troglodytes (Blumenbach, 1775), four adult males, nine adult females, four nonadults), and bonobos (Pan paniscus (Schwarz, 1929), two adult males, four adult females, two nonadults). We collected 195 samples (five per individual) of 39 captive individuals using cotton swabs and analyzed them using gas chromatography mass spectrometry. We compared the sample richness and intensity, similarity of chemical composition, and relative abundance of compounds. Results show that species, age, and potentially sex have an impact on the variance between odor profiles. Richness and intensity varied significantly between species (gorillas having the highest, bonobos the lowest richness and intensity), and with age (both increasing with age). Richness and intensity did not vary between sexes. Odor samples of the same species were more similar to each other than samples of different species. Among all compounds identified some were associated with age (N = 7), sex (N = 6), and species-related (N = 37) variance. Our study contributes to the basic understanding of olfactory communication in hominids by showing that the chemical composition of body odor varies across species and individuals, containing potentially important information for social communication.}, } @article {pmid31023888, year = {2019}, author = {Geist, KS and Strassmann, JE and Queller, DC}, title = {Family quarrels in seeds and rapid adaptive evolution in Arabidopsis.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {116}, number = {19}, pages = {9463-9468}, pmid = {31023888}, issn = {1091-6490}, mesh = {*Adaptation, Physiological ; Arabidopsis/*physiology ; *Biological Evolution ; Endosperm/*physiology ; }, abstract = {Evolutionary conflict can drive rapid adaptive evolution, sometimes called an arms race, because each party needs to respond continually to the adaptations of the other. Evidence for such arms races can sometimes be seen in morphology, in behavior, or in the genes underlying sexual interactions of host-pathogen interactions, but is rarely predicted a priori. Kin selection theory predicts that conflicts of interest should usually be reduced but not eliminated among genetic relatives, but there is little evidence as to whether conflict within families can drive rapid adaptation. Here we test multiple predictions about how conflict over the amount of resources an offspring receives from its parent would drive rapid molecular evolution in seed tissues of the flowering plant Arabidopsis As predicted, there is more adaptive evolution in genes expressed in Arabidopsis seeds than in other specialized organs, more in endosperms and maternal tissues than in embryos, and more in the specific subtissues involved in nutrient transfer. In the absence of credible alternative hypotheses, these results suggest that kin selection and conflict are important in plants, that the conflict includes not just the mother and offspring but also the triploid endosperm, and that, despite the conflict-reducing role of kinship, family members can engage in slow but steady tortoise-like arms races.}, } @article {pmid31002764, year = {2019}, author = {Sbarra, DA and Briskin, JL and Slatcher, RB}, title = {Smartphones and Close Relationships: The Case for an Evolutionary Mismatch.}, journal = {Perspectives on psychological science : a journal of the Association for Psychological Science}, volume = {14}, number = {4}, pages = {596-618}, doi = {10.1177/1745691619826535}, pmid = {31002764}, issn = {1745-6924}, mesh = {Biological Evolution ; Humans ; *Interpersonal Relations ; *Object Attachment ; *Smartphone ; *Social Behavior ; Trust ; }, abstract = {This article introduces and outlines the case for an evolutionary mismatch between smartphones and the social behaviors that help form and maintain close social relationships. As psychological adaptations that enhance human survival and inclusive fitness, self-disclosure and responsiveness evolved in the context of small kin networks to facilitate social bonds, promote trust, and enhance cooperation. These adaptations are central to the development of attachment bonds, and attachment theory is a middle-level evolutionary theory that provides a robust account of the ways human bonding provides for reproductive and inclusive fitness. Evolutionary mismatches operate when modern contexts cue ancestral adaptations in a manner that does not provide for their adaptive benefits. We argue that smartphones and their affordances, although highly beneficial in many circumstances, cue humans' evolved needs for self-disclosure and responsiveness across broad virtual networks and, in turn, have the potential to undermine immediate interpersonal interactions. We review emerging evidence on the topic of technoference, which is defined as the ways in which smartphone use may interfere with or intrude into everyday social interactions. The article concludes with an empirical agenda for advancing the integrative study of smartphones, intimacy processes, and close relationships.}, } @article {pmid30993671, year = {2019}, author = {Levin, SR and Grafen, A}, title = {Inclusive fitness is an indispensable approximation for understanding organismal design.}, journal = {Evolution; international journal of organic evolution}, volume = {73}, number = {6}, pages = {1066-1076}, pmid = {30993671}, issn = {1558-5646}, support = {//Natural Environment Research Council/International ; //Clarendon Fund/International ; //Hertford College, University of Oxford/International ; }, mesh = {Gene Frequency ; *Genetic Fitness ; *Models, Biological ; Models, Genetic ; *Selection, Genetic ; }, abstract = {For some decades most biologists interested in design have agreed that natural selection leads to organisms acting as if they are maximizing a quantity known as "inclusive fitness." This maximization principle has been criticized on the (uncontested) grounds that other quantities, such as offspring number, predict gene frequency changes accurately in a wider range of mathematical models. Here, we adopt a resolution offered by Birch, who accepts the technical difficulties of establishing inclusive fitness maximization in a fully general model, while concluding that inclusive fitness is still useful as an organizing framework. We set out in more detail why inclusive fitness is such a practical and powerful framework, and provide verbal and conceptual arguments for why social biology would be more or less impossible without it. We aim to help mathematicians understand why social biologists are content to use inclusive fitness despite its theoretical weaknesses. Here, we also offer biologists practical advice for avoiding potential pitfalls.}, } @article {pmid30967090, year = {2019}, author = {Cotter, SC and Pincheira-Donoso, D and Thorogood, R}, title = {Defences against brood parasites from a social immunity perspective.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1769}, pages = {20180207}, pmid = {30967090}, issn = {1471-2970}, mesh = {Animals ; Biological Evolution ; *Birds/parasitology/physiology ; *Cues ; *Host-Parasite Interactions ; *Insecta/parasitology/physiology ; *Recognition, Psychology ; *Social Behavior ; }, abstract = {Parasitic interactions are so ubiquitous that all multicellular organisms have evolved a system of defences to reduce their costs, whether the parasites they encounter are the classic parasites which feed on the individual, or brood parasites which usurp parental care. Many parallels have been drawn between defences deployed against both types of parasite, but typically, while defences against classic parasites have been selected to protect survival, those against brood parasites have been selected to protect the parent's inclusive fitness, suggesting that the selection pressures they impose are fundamentally different. However, there is another class of defences against classic parasites that have specifically been selected to protect an individual's inclusive fitness, known as social immunity. Social immune responses include the anti-parasite defences typically provided for others in kin-structured groups, such as the antifungal secretions produced by termite workers to protect the brood. Defences against brood parasites, therefore, are more closely aligned with social immune responses. Much like social immunity, host defences against brood parasitism are employed by a donor (a parent) for the benefit of one or more recipients (typically kin), and as with social defences against classic parasites, defences have therefore evolved to protect the donor's inclusive fitness, not the survival or ultimately the fitness of individual recipients This can lead to severe conflicts between the different parties, whose interests are not always aligned. Here, we consider defences against brood parasitism in the light of social immunity, at different stages of parasite encounter, addressing where conflicts occur and how they might be resolved. We finish with considering how this approach could help us to address longstanding questions in our understanding of brood parasitism. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.}, } @article {pmid30967088, year = {2019}, author = {Gloag, R and Beekman, M}, title = {The brood parasite's guide to inclusive fitness theory.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1769}, pages = {20180198}, pmid = {30967088}, issn = {1471-2970}, mesh = {Animals ; Birds/genetics/parasitology/*physiology ; Female ; *Genetic Fitness ; *Host-Parasite Interactions ; Insecta/genetics/parasitology/*physiology ; *Nesting Behavior ; Reproduction ; Social Behavior ; }, abstract = {Hamilton's theory of inclusive fitness provides a framework for understanding the evolution of social behaviour between kin, including parental and alloparental care. Brood parasitism is a reproductive tactic in which parasites exploit the care of other individuals of the same species (conspecific parasitism) or different species (interspecific parasitism) to rear their brood. Here, drawing from examples in birds and social insects, we identify two insights into brood parasitism that stem from inclusive fitness theory. First, the kin structure within nests, or between neighbouring nests, can create a niche space favouring the evolution of conspecific parasitism. For example, low average relatedness within social insect nests can increase selection for reproductive cheats. Likewise, high average relatedness between adjacent nests of some birds can increase a female's tolerance of parasitism by her neighbour. Second, intrabrood conflict will be high in parasitized broods, from the perspective of both parasite and host young, relative to unparasitized broods. We also discuss offspring recognition by hosts as an example of discrimination in a kin-selected social behaviour. We conclude that the inclusive fitness framework is instructive for understanding aspects of brood parasite and host evolution. In turn, brood parasites present some unique opportunities to test the predictions of inclusive fitness theory. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.}, } @article {pmid30966878, year = {2019}, author = {Vitikainen, EIK and Thompson, FJ and Marshall, HH and Cant, MA}, title = {Live long and prosper: durable benefits of early-life care in banded mongooses.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1770}, pages = {20180114}, pmid = {30966878}, issn = {1471-2970}, mesh = {Animals ; Cooperative Behavior ; Female ; *Helping Behavior ; Herpestidae/growth & development/*physiology ; *Longevity ; Male ; *Reproduction ; }, abstract = {Kin selection theory defines the conditions for which altruism or 'helping' can be favoured by natural selection. Tests of this theory in cooperatively breeding animals have focused on the short-term benefits to the recipients of help, such as improved growth or survival to adulthood. However, research on early-life effects suggests that there may be more durable, lifelong fitness impacts to the recipients of help, which in theory should strengthen selection for helping. Here, we show in cooperatively breeding banded mongooses (Mungos mungo) that care received in the first 3 months of life has lifelong fitness benefits for both male and female recipients. In this species, adult helpers called 'escorts' form exclusive one-to-one caring relationships with specific pups (not their own offspring), allowing us to isolate the effects of being escorted on later reproduction and survival. Pups that were more closely escorted were heavier at sexual maturity, which was associated with higher lifetime reproductive success for both sexes. Moreover, for female offspring, lifetime reproductive success increased with the level of escorting received per se, over and above any effect on body mass. Our results suggest that early-life social care has durable benefits to offspring of both sexes in this species. Given the well-established developmental effects of early-life care in laboratory animals and humans, we suggest that similar effects are likely to be widespread in social animals more generally. We discuss some of the implications of durable fitness benefits for the evolution of intergenerational helping in cooperative animal societies, including humans. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.}, } @article {pmid30966877, year = {2019}, author = {Kuijper, B and Johnstone, RA}, title = {The evolution of early-life effects on social behaviour-why should social adversity carry over to the future?.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {374}, number = {1770}, pages = {20180111}, pmid = {30966877}, issn = {1471-2970}, mesh = {Adaptation, Physiological ; Animals ; *Biological Evolution ; *Helping Behavior ; Humans ; Invertebrates/physiology ; *Selection, Genetic ; *Social Behavior ; Vertebrates/physiology ; }, abstract = {Numerous studies have shown that social adversity in early life can have long-lasting consequences for social behaviour in adulthood, consequences that may in turn be propagated to future generations. Given these intergenerational effects, it is puzzling why natural selection might favour such sensitivity to an individual's early social environment. To address this question, we model the evolution of social sensitivity in the development of helping behaviours, showing that natural selection indeed favours individuals whose tendency to help others is dependent on early-life social experience. In organisms with non-overlapping generations, we find that natural selection can favour positive social feedbacks, in which individuals who received more help in early life are also more likely to help others in adulthood, while individuals who received no early-life help develop low tendencies to help others later in life. This positive social sensitivity is favoured because of an intergenerational relatedness feedback: patches with many helpers tend to be more productive, leading to higher relatedness within the local group, which in turn favours higher levels of help in the next generation. In organisms with overlapping generations, this positive feedback is less likely to occur, and those who received more help may instead be less likely to help others (negative social feedback). We conclude that early-life social influences can lead to strong between-individual differences in helping behaviour, which can take different forms dependent on the life history in question. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'.}, } @article {pmid30963887, year = {2018}, author = {Schindler, S and Radford, AN}, title = {Factors influencing within-group conflict over defence against conspecific outsiders seeking breeding positions.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1893}, pages = {20181669}, pmid = {30963887}, issn = {1471-2954}, mesh = {Animals ; Birds/*physiology ; *Conflict, Psychological ; Female ; Fishes/*physiology ; Male ; Mammals/*physiology ; Models, Biological ; *Reproduction ; }, abstract = {In social species, groups face a variety of threats from conspecific outsiders. Defensive actions are therefore common, but there is considerable variation in which individuals contribute and to what extent. There has been some theoretical exploration of this variation when the defence is of shared resources, but the relative contributions when a single intruder threatens a particular breeding position have received less attention. Defensive actions are costly, both for the individual and dependent young, and contributions are likely to differ depending on individual sex, rank and size, current breeding stage, infanticide risk and relatedness levels. Here, we model analytically the relative fitness benefits of different group members to engaging in defence against individual intruders and determine when within-group conflicts of interest might arise over these defensive contributions. Conflicts of interest between the challenged breeder and other group members depend on relatedness to the brood and the potential relatedness reduction if an intruder acquires breeding status. Conflicts are more likely to occur when there is a low chance of winning the contest, low infanticide rates, inefficient defence from helpers, a long remaining brood-dependency period and high external (non-contest-related) mortality. Our work can help explain variation in defensive actions against out-group threats.}, } @article {pmid30963856, year = {2019}, author = {Faria, GS and Varela, SAM and Gardner, A}, title = {The social evolution of sleep: sex differences, intragenomic conflicts and clinical pathologies.}, journal = {Proceedings. Biological sciences}, volume = {286}, number = {1894}, pages = {20182188}, pmid = {30963856}, issn = {1471-2954}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Female ; Humans ; Male ; Models, Genetic ; Sex Characteristics ; Sleep/*physiology ; *Social Behavior ; }, abstract = {Sleep appears to be essential for most animals, including humans. Accordingly, individuals who sacrifice sleep are expected to incur costs and so should only be evolutionarily favoured to do this when these costs are offset by other benefits. For instance, a social group might benefit from having some level of wakefulness during the sleeping period if this guards against possible threats. Alternatively, individuals might sacrifice sleep in order to gain an advantage over mate competitors. Here, we perform a theoretical analysis of the social evolutionary pressures that drive investment into sleep versus wakefulness. Specifically, we: investigate how relatedness between social partners may modulate sleeping strategies, depending upon whether sleep sacrifice is selfish or altruistic; determine the conditions under which the sexes are favoured to adopt different sleeping strategies; identify the potential for intragenomic conflict between maternal-origin versus paternal-origin genes regarding an individual's sleeping behaviour; translate this conflict into novel and readily testable predictions concerning patterns of gene expression; and explore the concomitant effects of different kinds of mutations, epimutations, and uniparental disomies in relation to sleep disorders and other clinical pathologies. Our aim is to provide a theoretical framework for future empirical data and stimulate further research on this neglected topic.}, } @article {pmid30958139, year = {2019}, author = {Humphreys, RK and Ruxton, GD}, title = {Adaptive suicide: is a kin-selected driver of fatal behaviours likely?.}, journal = {Biology letters}, volume = {15}, number = {2}, pages = {20180823}, pmid = {30958139}, issn = {1744-957X}, mesh = {Animals ; Biological Evolution ; Host-Parasite Interactions ; Insecta ; *Parasites ; *Suicide ; Symbiosis ; }, abstract = {While several manipulated host behaviours are accepted as extended phenotypes of parasites, there remains debate over whether other altered behaviours in hosts following parasitic invasion represent cases of parasite manipulation, host defence or the pathology of infection. One particularly controversial subject is 'suicidal behaviour' in infected hosts. The host-suicide hypothesis proposes that host death benefits hosts doomed to reduced direct fitness by protecting kin from parasitism and therefore increasing inclusive fitness. However, adaptive suicide has been difficult to demonstrate conclusively as a host adaptation in studies on social or clonal insects, for whom high relatedness should enable greater inclusive fitness benefits. Following discussion of empirical and theoretical works from a behavioural ecology perspective, this review finds that the most persuasive evidence for selection of adaptive suicide comes from bacteria. Despite a focus on parasites, driven by the existing literature, the potential for the evolution of adaptive suicidal behaviour in hosts is also considered to apply to cases of infection by pathogens, provided that the disease has a severe effect on direct fitness and that suicidal behaviour can affect pathogen transmission dynamics. Suggestions are made for future research and a broadening of the possible implications for coevolution between parasites and hosts.}, } @article {pmid30949227, year = {2019}, author = {Spring, S and Lehner, M and Huber, L and Ringler, E}, title = {Oviposition and father presence reduce clutch cannibalism by female poison frogs.}, journal = {Frontiers in zoology}, volume = {16}, number = {}, pages = {8}, pmid = {30949227}, issn = {1742-9994}, abstract = {BACKGROUND: The consumption of conspecific young by adult individuals is a common phenomenon across various animal taxa. Possible adaptive benefits of such behaviour include the acquisition of nutrients, decreased competition for one's own offspring, and/or increased mating opportunities. Clutch cannibalism has occasionally been observed in several species of Neotropical poison frogs, but the circumstances under which this behaviour occurs has rarely been investigated experimentally. Recent experiments with the poison frog Allobates femoralis have shown that males indiscriminately transport all clutches located inside their own territory to bodies of water, but become highly cannibalistic when taking over a new territory. Females are able to indirectly discriminate between their own and foreign clutches by location and take over transport duties of their own clutches only in the absence of the father. Cannibalism by A. femoralis females has not been previously observed. We thus asked if, and under which circumstances, cannibalism of unrelated clutches by female A. femoralis would occur, by manipulating the presence of the clutch's father, the female's own reproductive state, and the female's familiarity with the environment.

RESULTS: Females clearly cannibalize foreign clutches. Cannibalism was most pronounced when the female had not recently produced her own clutch and the father of the foreign clutch was absent. The female's familiarity with the area had no significant influence on the likelihood of cannibalism to occur.

CONCLUSIONS: Our data indicate that both previous oviposition and the father's presence reduce cannibalistic behaviour in A. femoralis females. Cannibalistic females may gain nutritional benefits or enhanced inclusive fitness by preying on other females' offspring. The finding that the father's presence at the clutch site/territory was sufficient to reduce cannibalism by females suggests a prominent role of male territoriality for the evolution of male parental care.}, } @article {pmid30940017, year = {2019}, author = {Smith, AR and Kapheim, KM and Kingwell, CJ and Wcislo, WT}, title = {A split sex ratio in solitary and social nests of a facultatively social bee.}, journal = {Biology letters}, volume = {15}, number = {4}, pages = {20180740}, pmid = {30940017}, issn = {1744-957X}, mesh = {Altruism ; Animals ; Bees ; Biological Evolution ; Female ; Male ; Reproduction ; *Sex Ratio ; *Social Behavior ; }, abstract = {A classic prediction of kin selection theory is that a mixed population of social and solitary nests of haplodiploid insects should exhibit a split sex ratio among offspring: female biased in social nests, male biased in solitary nests. Here, we provide the first evidence of a solitary-social split sex ratio, using the sweat bee Megalopta genalis (Halictidae). Data from 2502 offspring collected from naturally occurring nests across 6 years spanning the range of the M. genalis reproductive season show that despite significant yearly and seasonal variation, the offspring sex ratio of social nests is consistently more female biased than in solitary nests. This suggests that split sex ratios may facilitate the evolutionary origins of cooperation based on reproductive altruism via kin selection.}, } @article {pmid30795688, year = {2019}, author = {Atchison, BJ and Goodwin, DL}, title = {"My Child May Be Ready, but I Am Not": Parents' Experiences of Their Children's Transition to Inclusive Fitness Settings.}, journal = {Adapted physical activity quarterly : APAQ}, volume = {36}, number = {2}, pages = {282-301}, doi = {10.1123/apaq.2018-0101}, pmid = {30795688}, issn = {1543-2777}, mesh = {Adolescent ; Adult ; Child ; Disabled Persons ; *Exercise ; Fear ; Female ; Financing, Government ; Fitness Centers ; Government Programs ; Humans ; Internal-External Control ; Interviews as Topic ; Male ; Middle Aged ; Parents/*psychology ; Qualitative Research ; Young Adult ; }, abstract = {Parents play an essential role in the transition from separate physical activity programs to inclusive settings for their children. The purpose of this study was to explore experiences of parents as they anticipate and prepare for their children experiencing disability to transition, understand strategies used to address transition, and gain insights into the supports important to families during transition. Using an interpretative phenomenological analysis research approach, semistructured one-on-one interviews were conducted with 8 parents whose children were undergoing the transition from separate to inclusive community fitness contexts. Four themes described the experiences of parents as they anticipated, prepared for, and supported their child to transition: My child may be ready, but I am not; fear of outside judgment; playing by their rules; and reframing our thinking. Using Schlossberg's model, the tensions parents faced as they negotiated new roles, relationships, routines, and assumptions as they moved through the transition process were uncovered. The parents experienced transition alongside their children, providing insights for fitness and health-promotion professionals. Without preparation for transition, apprehensions and hesitancy may postpone or prevent their children's transition to community programs.}, } @article {pmid30787361, year = {2019}, author = {David-Barrett, T}, title = {Network Effects of Demographic Transition.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {2361}, pmid = {30787361}, issn = {2045-2322}, abstract = {Traditional human societies use two of biology's solutions to reduce free-riding: by collaborating with relatives, they rely on the mechanism of kin-selection, and by forming highly clustered social kin-networks, they can efficiently use reputation dynamics. Both of these solutions assume the presence of relatives. This paper shows how social networks change during demographic transition. With falling fertility, there are fewer children that could be relatives to one another. As the missing kin are replaced by non-kin friends, local clustering in the social network drops. This effect is compounded by increasing population size, characteristic of demographic transition. The paper also shows that the speed at which reputation spreads in the network slows down due to both falling fertility and increasing group size. Thus, demographic transition weakens both mechanisms for eliminating free-riders: there are fewer relatives around, and reputation spreads slower. This new link between falling fertility and the altered structure of the social network offers novel interpretations of the origins of legal institutions, the Small World phenomenon, the social impact of urbanisation, and the birds-of-a-feather friendship choice heuristic.}, } @article {pmid30744976, year = {2019}, author = {Engelhardt, SC and Bergeron, P and Gagnon, A and Dillon, L and Pelletier, F}, title = {Using Geographic Distance as a Potential Proxy for Help in the Assessment of the Grandmother Hypothesis.}, journal = {Current biology : CB}, volume = {29}, number = {4}, pages = {651-656.e3}, doi = {10.1016/j.cub.2019.01.027}, pmid = {30744976}, issn = {1879-0445}, mesh = {Aged ; Aged, 80 and over ; Family Characteristics/*history ; Female ; France/ethnology ; Genetic Fitness/*physiology ; Geography ; *Grandparents ; History, 17th Century ; History, 18th Century ; Humans ; *Longevity ; Middle Aged ; Mortality/*history ; Quebec ; }, abstract = {Life-history theory predicts that selection could favor the decoupling of somatic and reproductive senescence if post-reproductive lifespan (PRLS) provides additional indirect fitness benefits [1, 2]. The grandmother hypothesis proposes that prolonged PRLS evolved because post-reproductive grandmothers gain inclusive fitness benefits by helping their daughters and grandchildren [3, 4]. Because most historical human data do not report direct evidence of help, we hypothesized that geographic distance between individuals may be inversely related to their capacity to help. Using an exceptionally detailed dataset of pre-industrial French settlers in the St. Lawrence Valley during the 17[th] and 18[th] centuries, we assessed the potential for grandmothers to improve their inclusive fitness by helping their descendants, and we evaluated how this effect varied with geographic distance, ranging between 0 and 325 km, while accounting for potential familial genetic and environmental effects [5-9]. Grandmothers (F0) who were alive allowed their daughters (F1) to increase their number of offspring (F2) born by 2.1 and to increase their number of offspring surviving to 15 years of age by 1.1 compared to when grandmothers were dead. However, the age at first reproduction was not influenced by the life status (alive or dead) of grandmothers. As geographic distance increased, the number of offspring born and lifetime reproductive success decreased, while the age at first reproduction increased, despite the grandmother being alive in these analyses. Our study suggests that geographic proximity has the potential to modulate inclusive fitness, supporting the grandmother hypothesis, and to contribute to our understanding of the evolution of PRLS.}, } @article {pmid30744967, year = {2019}, author = {Chapman, SN and Pettay, JE and Lummaa, V and Lahdenperä, M}, title = {Limits to Fitness Benefits of Prolonged Post-reproductive Lifespan in Women.}, journal = {Current biology : CB}, volume = {29}, number = {4}, pages = {645-650.e3}, doi = {10.1016/j.cub.2018.12.052}, pmid = {30744967}, issn = {1879-0445}, mesh = {Aged ; Aged, 80 and over ; Family Characteristics ; Female ; Finland ; Genetic Fitness/*physiology ; *Grandparents ; Humans ; *Longevity ; Middle Aged ; Postmenopause/*physiology ; }, abstract = {Recent advances in medicine and life-expectancy gains have fueled multidisciplinary research into the limits of human lifespan [1-3]. Ultimately, how long humans can live for may depend on selection favoring extended longevity in our evolutionary past [4]. Human females have an unusually extended post-reproductive lifespan, which has been explained by the fitness benefits provided from helping to raise grandchildren following menopause [5, 6]. However, formal tests of whether such grandmothering benefits wane with grandmother age and explain the observed length of post-reproductive lifespan are missing. This is critical for understanding prevailing selection pressures on longevity but to date has been overlooked as a possible mechanism driving the evolution of lifespan. Here, we use extensive data from pre-industrial humans to show that fitness gains from grandmothering are dependent on grandmother age, affecting selection on the length of post-reproductive lifespan. We find both opportunities and ability to help grandchildren declined with age, while the hazard of death of women increased greatly in their late 60s and 70s compared to menopausal ages, together implying waning selection on subsequent longevity. The presence of maternal grandmothers aged 50-75 increased grandchild survival after weaning, confirming the fitness advantage of post-reproductive lifespan. However, co-residence with paternal grandmothers aged 75+ was detrimental to grandchild survival, with those grandmothers close to death and presumably in poorer health particularly associated with lower grandchild survival. The age limitations of gaining inclusive fitness from grandmothering suggests that grandmothering can select for post-reproductive longevity only up to a certain point.}, } @article {pmid30720369, year = {2019}, author = {Almond, EJ and Huggins, TJ and Crowther, LP and Parker, JD and Bourke, AFG}, title = {Queen Longevity and Fecundity Affect Conflict with Workers over Resource Inheritance in a Social Insect.}, journal = {The American naturalist}, volume = {193}, number = {2}, pages = {256-266}, doi = {10.1086/701299}, pmid = {30720369}, issn = {1537-5323}, mesh = {*Aggression ; Animals ; Bees/*physiology ; Female ; *Fertility ; *Longevity ; Male ; *Models, Biological ; Reproduction ; }, abstract = {Resource inheritance is a major source of conflict in animal societies. However, the assumptions and predictions of models of conflict over resource inheritance have not been systematically tested within a single system. We developed an inclusive fitness model for annual eusocial Hymenoptera that predicts a zone of conflict in which future reproductive workers are selected to enforce nest inheritance before the queen is selected to cede the nest. We experimentally tested key elements of this model in the bumblebee Bombus terrestris. In colonies from which queens were sequentially removed, queen tenure was significantly negatively associated with worker male production, confirming that workers gain direct fitness by usurping the queen. In unmanipulated colonies, queen fecundity decreased significantly over the latter part of the colony cycle, confirming that workers' indirect fitness from maintaining queens declines over time. Finally, in an experiment simulating loss of queen fecundity by removal of queens' eggs, worker-to-queen aggression increased significantly and aggressive workers were significantly more likely to become egg layers, consistent with workers monitoring queen fecundity to assess the net benefit of future reproduction. Overall, by upholding key assumptions and predictions of the model, our results provide novel empirical support for kin-selected conflict over resource inheritance.}, } @article {pmid30718704, year = {2019}, author = {Amici, F and Sánchez-Amaro, A and Sebastián-Enesco, C and Cacchione, T and Allritz, M and Salazar-Bonet, J and Rossano, F}, title = {The word order of languages predicts native speakers' working memory.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {1124}, pmid = {30718704}, issn = {2045-2322}, mesh = {Adolescent ; Adult ; Africa ; Asia ; Comprehension ; Europe ; Female ; Functional Laterality/*physiology ; Humans ; *Language ; Male ; Memory, Short-Term/*physiology ; Speech Perception ; Thinking/*physiology ; Young Adult ; }, abstract = {The relationship between language and thought is controversial. One hypothesis is that language fosters habits of processing information that are retained even in non-linguistic domains. In left-branching (LB) languages, modifiers usually precede the head, and real-time sentence comprehension may more heavily rely on retaining initial information in working memory. Here we presented a battery of working memory and short-term memory tasks to adult native speakers of four LB and four right-branching (RB) languages from Africa, Asia and Europe. In working memory tasks, LB speakers were better than RB speakers at recalling initial stimuli, but worse at recalling final stimuli. Our results show that the practice of parsing sentences in specific directions due to the syntax and word order of our native language not only predicts the way we remember words, but also other non-linguistic stimuli.}, } @article {pmid30706446, year = {2019}, author = {Grueter, CC and Hale, J and Jin, R and Judge, D and Stoinski, T}, title = {Infant handling by female mountain gorillas: Establishing its frequency, function, and (ir)relevance for life history evolution.}, journal = {American journal of physical anthropology}, volume = {168}, number = {4}, pages = {744-749}, doi = {10.1002/ajpa.23791}, pmid = {30706446}, issn = {1096-8644}, mesh = {Animals ; Animals, Newborn/physiology ; Anthropology, Physical ; Behavior, Animal/*physiology ; Female ; Gorilla gorilla/*physiology ; Male ; Maternal Behavior/*physiology ; Rwanda ; }, abstract = {OBJECTIVES: Infant handling describes cases in which youngsters are temporarily removed from the care of their mothers and "taken care of" (held, carried, etc.) by other conspecifics. Handlers may gain indirect fitness benefits from these actions and can practice mothering skills, thereby improving the odds of survival of their own infants. Great apes are notable for displaying little infant handling. Apart from anecdotal observations, no published data exist on infant handling in wild mountain gorillas. We tested two of the most pertinent explanations ("kin selection" and "learning to mother") in a wild population of mountain gorillas in Rwanda. We predicted that (a) nulliparous females would exhibit infant handling (i.e., carrying) more than parous females and (b) maternal kin would exhibit more infant handling than nonkin.

METHODS: We collated 8 years of data on infant carrying behavior collected in 13 groups monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center.

RESULTS: Infant handling is an infrequent behavior (1,783 instances over 25,600 observation hours). A strong positive effect of relatedness and handler parity on the frequency of infant handling emerged.

CONCLUSIONS: While the nature of handler-infant interactions (affiliative, abusive, etc.) remains unstudied, they could constitute alloparental care and could therefore attenuate maternal energetic burden and ultimately allow increased birth rates. However, the rarity of this behavior makes it an unlikely contributor to mountain gorillas' relatively short interbirth intervals.}, } @article {pmid30700283, year = {2019}, author = {Bose, APH and Henshaw, JM and Zimmermann, H and Fritzsche, K and Sefc, KM}, title = {Inclusive fitness benefits mitigate costs of cuckoldry to socially paired males.}, journal = {BMC biology}, volume = {17}, number = {1}, pages = {2}, pmid = {30700283}, issn = {1741-7007}, support = {P 27605/FWF_/Austrian Science Fund FWF/Austria ; }, mesh = {Animals ; Behavior, Animal/*physiology ; Cichlids/physiology ; Female ; Male ; Reproduction/*physiology ; Sexual Behavior, Animal/*physiology ; *Social Behavior ; }, abstract = {BACKGROUND: In socially monogamous species, reproduction is not always confined to paired males and females. Extra-pair males commonly also reproduce with paired females, which is traditionally thought to be costly to the females' social partners. However, we suggest that when the relatedness between reproducing individuals is considered, cuckolded males can suffer lower fitness losses than otherwise expected, especially when the rate of cuckoldry is high. We combine theoretical modeling with a detailed genetic study on a socially monogamous wild fish, Variabilichromis moorii, which displays biparental care despite exceptionally high rates of extra-pair paternity.

RESULTS: We measured the relatedness between all parties involved in V. moorii spawning events (i.e. between males and females in social pairs, females and their extra-pair partners, and paired males and their cuckolders), and we reveal that males are on average more related to their cuckolders than expected by chance. Queller-Goodnight estimates of relatedness between males and their cuckolders are on average r = 0.038 but can range up to r = 0.64. This also increases the relatedness between males and the extra-pair offspring under their care. These intriguing results are consistent with the predictions of our mathematical model, which shows that elevated relatedness between paired males and their cuckolders can be adaptive for both parties when competition for fertilizations is strong.

CONCLUSIONS: Our results show how cuckoldry by relatives can offset males' direct fitness losses with inclusive fitness gains, which can be substantial in systems where males face almost certain paternity losses.}, } @article {pmid30689139, year = {2019}, author = {Grodwohl, JB}, title = {Animal Behavior, Population Biology and the Modern Synthesis (1955-1985).}, journal = {Journal of the history of biology}, volume = {52}, number = {4}, pages = {597-633}, pmid = {30689139}, issn = {1573-0387}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Ethology/*history ; Genetics, Population/*history ; History, 20th Century ; Models, Biological ; *Selection, Genetic ; Sociobiology/history ; }, abstract = {This paper examines the history of animal behavior studies after the synthesis period. Three episodes are considered: the adoption of the theory of natural selection, the mathematization of ideas, and the spread of molecular methods in behavior studies. In these three episodes, students of behavior adopted practices and standards developed in population ecology and population genetics. While they borrowed tools and methods from these fields, they made distinct uses (inclusive fitness method, evolutionary theory of games, emphasis on individual selection) that set them relatively apart and led them to contribute, in their own way, to evolutionary theory. These episodes also highlight some limitations of "conjunction narratives" centered on the relation between a discipline and the modern synthesis. A trend in conjunction narratives is to interpret any development related to evolution in a discipline as an "extension," an "integration," or as a "delayed" synthesis. I here suggest that this can lead to underestimate discontinuities in the history of evolutionary biology.}, } @article {pmid30672052, year = {2019}, author = {Patel, M and Raymond, B and Bonsall, MB and West, SA}, title = {Crystal toxins and the volunteer's dilemma in bacteria.}, journal = {Journal of evolutionary biology}, volume = {32}, number = {4}, pages = {310-319}, pmid = {30672052}, issn = {1420-9101}, support = {BB/M011224/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Bacteria/metabolism ; *Bacterial Physiological Phenomena ; Bacterial Toxins/*biosynthesis/chemistry/toxicity ; Biological Evolution ; Host-Pathogen Interactions/*physiology ; *Models, Biological ; Population Density ; }, abstract = {The growth and virulence of the bacteria Bacillus thuringiensis depend on the production of Cry toxins, which are used to perforate the gut of its host. Successful invasion of the host relies on producing a threshold amount of toxin, after which there is no benefit from producing more toxin. Consequently, the production of Cry toxin appears to be a different type of social problem compared with the public goods scenarios that bacteria usually encounter. We show that selection for toxin production is a volunteer's dilemma. We make specific predictions that (a) selection for toxin production depends upon an interplay between the number of bacterial cells that each host ingests and the genetic relatedness between those cells; (b) cheats that do not produce toxin gain an advantage when at low frequencies, and at high bacterial density, allowing them to be maintained in a population alongside toxin-producing cells. More generally, our results emphasize the diversity of the social games that bacteria play.}, } @article {pmid30655189, year = {2019}, author = {Barstow, BA and Vice, J and Bowman, S and Mehta, T and Kringen, S and Axelson, P and Padalabalanarayanan, S}, title = {Examining perceptions of existing and newly created accessibility symbols.}, journal = {Disability and health journal}, volume = {12}, number = {2}, pages = {180-186}, doi = {10.1016/j.dhjo.2018.11.012}, pmid = {30655189}, issn = {1876-7583}, mesh = {Adult ; Aged ; Aged, 80 and over ; *Comprehension ; Disabled Persons/*psychology ; *Equipment Design ; Female ; Humans ; *Location Directories and Signs ; Male ; Middle Aged ; Surveys and Questionnaires ; United States ; }, abstract = {BACKGROUND: Symbols are used to convey messages in a clear, understandable manner, without the use of written language. The most widely recognized symbol used to denote access for persons with disabilities is the International Symbol of Access. This symbol has been criticized for its inadequate representation of disability diversity poorly representing universal design of space and products.

OBJECTIVE: This descriptive study explored individual comprehension and perceptions of nine existing and newly created accessibility pictograph symbols and identified one that represented universal access to fitness equipment.

METHODS: A survey was disseminated electronically and face-to-face to individuals, groups and organizations affiliated with inclusive fitness equipment, space and programming. Quantitative data was analyzed for descriptive statistics, rank order of symbols and group comparisons of rankings. Thematic analysis of open-ended question results revealed themes to enhance understanding of symbol rank order.

RESULTS: 981 participants completed the survey. Symbol four, shaped as a Venn diagram containing three icons representing individuals with varying ability levels, was ranked highest with no significant differences in group comparisons between participants with and without a disability and U.S. residents versus non-U.S. residents. 85.4% of participants demonstrated accurate comprehension of this symbol. Though symbol five had the same symbol rank median value, this symbol's distribution of scores was lower.

CONCLUSIONS: Participants accurately comprehended symbol four and it was identified as the highest ranked symbol representing universal access to fitness equipment. Because of symbol unfamiliarity, adoption will require education and consistency of use and placement.}, } @article {pmid30639341, year = {2019}, author = {Lohr, JN and Galimov, ER and Gems, D}, title = {Does senescence promote fitness in Caenorhabditis elegans by causing death?.}, journal = {Ageing research reviews}, volume = {50}, number = {}, pages = {58-71}, pmid = {30639341}, issn = {1872-9649}, support = {/WT_/Wellcome Trust/United Kingdom ; 098565/Z/12/Z/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Aging/pathology/*physiology ; Animals ; Apoptosis/physiology ; Biological Evolution ; Caenorhabditis elegans/*physiology ; Cellular Senescence/*physiology ; Physical Fitness/*physiology ; }, abstract = {A widely appreciated conclusion from evolutionary theory is that senescence (aging) is of no adaptive value to the individual that it afflicts. Yet studies of Caenorhabditis elegans and Saccharomyces cerevisiae are increasingly revealing the presence of processes which actively cause senescence and death, leading some biogerontologists to wonder about the established theory. Here we argue that programmed death that increases fitness could occur in C. elegans and S. cerevisiae, and that this is consistent with the classic evolutionary theory of aging. This is because of the special conditions under which these organisms have evolved, particularly the existence of clonal populations with limited dispersal and, in the case of C. elegans, the brevity of the reproductive period caused by protandrous hermaphroditism. Under these conditions, death-promoting mechanisms could promote worm fitness by enhancing inclusive fitness, or worm colony fitness through group selection. Such altruistic, adaptive death is not expected to evolve in organisms with outbred, dispersed populations (e.g. most vertebrate species). The plausibility of adaptive death in C. elegans is supported by computer modelling studies, and new knowledge about the ecology of this species. To support these arguments we also review the biology of adaptive death, and distinguish three forms: consumer sacrifice, biomass sacrifice and defensive sacrifice.}, } @article {pmid30629594, year = {2019}, author = {Narasimha, S and Nagornov, KO and Menin, L and Mucciolo, A and Rohwedder, A and Humbel, BM and Stevens, M and Thum, AS and Tsybin, YO and Vijendravarma, RK}, title = {Drosophila melanogaster cloak their eggs with pheromones, which prevents cannibalism.}, journal = {PLoS biology}, volume = {17}, number = {1}, pages = {e2006012}, pmid = {30629594}, issn = {1545-7885}, mesh = {Alkadienes/*metabolism ; Animals ; Cannibalism ; Drosophila Proteins/metabolism ; Drosophila melanogaster/metabolism ; Female ; Larva ; Ovum/*physiology ; Pheromones/*metabolism ; Predatory Behavior/physiology ; Sexual Behavior, Animal/physiology ; }, abstract = {Oviparous animals across many taxa have evolved diverse strategies that deter egg predation, providing valuable tests of how natural selection mitigates direct fitness loss. Communal egg laying in nonsocial species minimizes egg predation. However, in cannibalistic species, this very behavior facilitates egg predation by conspecifics (cannibalism). Similarly, toxins and aposematic signaling that deter egg predators are often inefficient against resistant conspecifics. Egg cannibalism can be adaptive, wherein cannibals may benefit through reduced competition and added nutrition, but since it reduces Darwinian fitness, the evolution of anticannibalistic strategies is rife. However, such strategies are likely to be nontoxic because deploying toxins against related individuals would reduce inclusive fitness. Here, we report how D. melanogaster use specific hydrocarbons to chemically mask their eggs from cannibal larvae. Using an integrative approach combining behavioral, sensory, and mass spectrometry methods, we demonstrate that maternally provisioned pheromone 7,11-heptacosadiene (7,11-HD) in the eggshell's wax layer deters egg cannibalism. Furthermore, we show that 7,11-HD is nontoxic, can mask underlying substrates (for example, yeast) when coated upon them, and its detection requires pickpocket 23 (ppk23) gene function. Finally, using light and electron microscopy, we demonstrate how maternal pheromones leak-proof the egg, consequently concealing it from conspecific larvae. Our data suggest that semiochemicals possibly subserve in deceptive functions across taxa, especially when predators rely on chemical cues to forage, and stimulate further research on deceptive strategies mediated through nonvisual sensory modules. This study thus highlights how integrative approaches can illuminate our understanding on the adaptive significance of deceptive defenses and the mechanisms through which they operate.}, } @article {pmid30624681, year = {2019}, author = {Aumer, D and Stolle, E and Allsopp, M and Mumoki, F and Pirk, CWW and Moritz, RFA}, title = {A Single SNP Turns a Social Honey Bee (Apis mellifera) Worker into a Selfish Parasite.}, journal = {Molecular biology and evolution}, volume = {36}, number = {3}, pages = {516-526}, pmid = {30624681}, issn = {1537-1719}, mesh = {Altruism ; Animals ; Bees/*genetics ; Female ; Parthenogenesis/*genetics ; Polymorphism, Single Nucleotide ; Selection, Genetic ; }, abstract = {The evolution of altruism in complex insect societies is arguably one of the major transitions in evolution and inclusive fitness theory plausibly explains why this is an evolutionary stable strategy. Yet, workers of the South African Cape honey bee (Apis mellifera capensis) can reverse to selfish behavior by becoming social parasites and parthenogenetically producing female offspring (thelytoky). Using a joint mapping and population genomics approach, in combination with a time-course transcript abundance dynamics analysis, we show that a single nucleotide polymorphism at the mapped thelytoky locus (Th) is associated with the iconic thelytokous phenotype. Th forms a linkage group with the ecdysis-triggering hormone receptor (Ethr) within a nonrecombining region under strong selection in the genome. A balanced detrimental allele system plausibly explains why the trait is specific to A. m. capensis and cannot easily establish itself into genomes of other honey bee subspecies.}, } @article {pmid30564400, year = {2018}, author = {Hare, D and Blossey, B and Reeve, HK}, title = {Value of species and the evolution of conservation ethics.}, journal = {Royal Society open science}, volume = {5}, number = {11}, pages = {181038}, pmid = {30564400}, issn = {2054-5703}, abstract = {The theory of evolution by natural selection can help explain why people care about other species. Building upon recent insights that morality evolves to secure fitness advantages of cooperation, we propose that conservation ethics (moral beliefs, attitudes, intuitions and norms regarding other species) could be adaptations that support cooperation between humans and non-humans. We present eco-evolutionary cost-benefit models of conservation behaviours as interspecific cooperation (altruism towards members of other species). We find that an evolutionary rule identical in structure to Hamilton's rule (which explains altruistic behaviour towards related conspecifics) can explain altruistic behaviour towards members of other species. Natural selection will favour traits for selectively altering the success of members of other species (e.g. conserving them) in ways that maximize inclusive fitness return benefits. Conservation behaviours and the ethics that evolve to reinforce them will be sensitive to local ecological and socio-cultural conditions, so will assume different contours in different places. Difficulties accurately assessing costs and benefits provided by other species, time required to adapt to ecological and socio-cultural change and barriers to collective action could explain the apparent contradiction between the widespread existence of conservation ethics and patterns of biodiversity decline globally.}, } @article {pmid30557568, year = {2019}, author = {Eshel, I}, title = {Mutual altruism and long-term optimization of the inclusive fitness in multilocus genetic systems.}, journal = {Theoretical population biology}, volume = {129}, number = {}, pages = {126-132}, doi = {10.1016/j.tpb.2018.10.005}, pmid = {30557568}, issn = {1096-0325}, mesh = {*Altruism ; *Genetic Fitness ; *Genetics, Population ; Humans ; Models, Statistical ; *Population Dynamics ; }, abstract = {The dynamics of long-term evolution in a complex genetically-structured population with a flux of random mutations is employed here to study the evolution of mutual altruism between relatives that are encountered repeatedly, where the level of altruism is measured by the risk one is willing to accept in order to save the life of one's relative. It is shown that regardless of the number of loci involved, of the rates of recombination among them, and of the intensity of the selection forces, the long-term dynamics can phenotypically converge only to a level of altruism that maximizes the individual inclusive fitness as it has previously defined by students of the individual approach to evolution. Except for the widely studied case of weak selection, however, the convergence to such a level of altruism is not necessarily generation-to-next monotone. It is further shown that, unlike the case of the one-shot encounter, repeated encounters between relatives allow for more than one level of altruism which may maximize the inclusive fitness, in which case not all such levels of altruism are evolutionarily accessible.}, } @article {pmid30464831, year = {2018}, author = {Clarke, PMR and McElreath, MB and Barrett, BJ and Mabry, KE and McElreath, R}, title = {The evolution of bequeathal in stable habitats.}, journal = {Ecology and evolution}, volume = {8}, number = {21}, pages = {10594-10607}, pmid = {30464831}, issn = {2045-7758}, abstract = {Adults sometimes disperse, while philopatric offspring inherit the natal site, a pattern known as bequeathal. Despite a decades-old empirical literature, little theoretical work has explored when natural selection may favor bequeathal. We present a simple mathematical model of the evolution of bequeathal in a stable environment, under both global and local dispersal. We find that natural selection favors bequeathal when adults are competitively advantaged over juveniles, baseline mortality is high, the environment is unsaturated, and when juveniles experience high dispersal mortality. However, frequently bequeathal may not evolve, because the fitness cost for the adult is too large relative to inclusive fitness benefits. Additionally, there are many situations for which bequeathal is an ESS, yet cannot invade the population. As bequeathal in real populations appears to be facultative, yet-to-be-modeled factors like timing of birth in the breeding season may strongly influence the patterns seen in natural populations.}, } @article {pmid30457220, year = {2019}, author = {Amici, F}, title = {An Evolutionary Approach to the Study of Collaborative Remembering?.}, journal = {Topics in cognitive science}, volume = {11}, number = {4}, pages = {811-816}, doi = {10.1111/tops.12398}, pmid = {30457220}, issn = {1756-8765}, mesh = {Adaptation, Psychological/physiology ; Biological Evolution ; *Cooperative Behavior ; Humans ; Knowledge ; Memory/*physiology ; Mental Recall/*physiology ; Social Behavior ; Social Learning/physiology ; }, abstract = {Hope and Gabbert (2008) and Jay and colleagues (in press) show us that collaborative remembering, in certain contexts, may result in incomplete and less accurate memories. Here, I will discuss the evolutionary origins of this behavior, linking it to phenomena such as social contagion, conformity, and social learning, which are highly adaptive and widespread across non-human taxa.}, } @article {pmid30455506, year = {2018}, author = {Ruiz-Lambides, AV and Weiß, BM and Kulik, L and Widdig, A}, title = {Which male and female characteristics influence the probability of extragroup paternities in rhesus macaques, Macaca mulatta?.}, journal = {Animal behaviour}, volume = {140}, number = {}, pages = {119-127}, pmid = {30455506}, issn = {0003-3472}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {Extragroup paternity (EGP) is found across a wide range of species and may entail reproductive benefits, but may also entail costs to both sexes. While population and group parameters affecting the degree of EGPs are relatively well established, less is known about the individual characteristics that make males and females engage in alternative reproductive tactics such as EGP. Applying a combination of long-term demographic and genetic data from the rhesus macaque population of Cayo Santiago (Puerto Rico, U.S.A.), we investigate which male and female characteristics influence the probability of EGP to better understand the circumstances that shape the distribution and occurrence of EGP. Our results show that, against our expectations, higher-ranking females were more likely to produce EGP offspring than lower- ranking females. The probability of producing extragroup offspring was not significantly related to female or male age, male tenure or previous reproductive success. Furthermore, genetic relatedness between the parents did not affect the production of extragroup offspring, but extragroup offspring were more frequently produced early rather than late in a given mating season. Altogether, our analysis suggests that individual attributes and seasonal aspects create different opportunities and preferences for engaging in EGP as an alternative reproductive tactic. The observed patterns of EGP in rhesus macaques appear to be consistent with female mate choice for genetic benefits, which needs to be confirmed in future studies.}, } @article {pmid30450066, year = {2018}, author = {Antfolk, J and Lieberman, D and Harju, C and Albrecht, A and Mokros, A and Santtila, P}, title = {Opposition to Inbreeding Between Close Kin Reflects Inclusive Fitness Costs.}, journal = {Frontiers in psychology}, volume = {9}, number = {}, pages = {2101}, pmid = {30450066}, issn = {1664-1078}, abstract = {Due to the intense selection pressure against inbreeding, humans are expected to possess psychological adaptations that regulate mate choice and avoid inbreeding. From a gene's-eye perspective, there is little difference in the evolutionary costs between situations where an individual him/herself is participating in inbreeding and inbreeding among other close relatives. The difference is merely quantitative, as fitness can be compromised via both routes. The question is whether humans are sensitive to the direct as well as indirect costs of inbreeding. Using responses from a large population-based sample (27,364 responses from 2,353 participants), we found that human motivations to avoid inbreeding closely track the theoretical costs of inbreeding as predicted by inclusive fitness theory. Participants were asked to select in a forced choice paradigm, which of two acts of inbreeding with actual family members they would want to avoid most. We found that the estimated fitness costs explained 83.6% of participant choices. Importantly, fitness costs explained choices also when the self was not involved. We conclude that humans intuit the indirect fitness costs of mating decisions made by close family members and that psychological inbreeding avoidance mechanisms extend beyond self-regulation.}, } @article {pmid30444662, year = {2018}, author = {Mullon, C and Lehmann, L}, title = {Eco-Evolutionary Dynamics in Metacommunities: Ecological Inheritance, Helping within Species, and Harming between Species.}, journal = {The American naturalist}, volume = {192}, number = {6}, pages = {664-686}, doi = {10.1086/700094}, pmid = {30444662}, issn = {1537-5323}, mesh = {Altruism ; Animals ; *Biological Evolution ; *Biota ; Demography ; Ecosystem ; Models, Theoretical ; Population Dynamics ; Selection, Genetic ; }, abstract = {Understanding selection on intra- and interspecific interactions that take place in dispersal-limited communities is a challenge for ecology and evolutionary biology. The problem is that local demographic stochasticity generates eco-evolutionary dynamics that are generally too complicated to make tractable analytical investigations. Here we circumvent this problem by approximating the selection gradient on a quantitative trait that influences local community dynamics, assuming that such dynamics are deterministic with a stable fixed point. The model nonetheless captures unavoidable kin selection effects arising from demographic stochasticity. Our approximation reveals that selection depends on how an individual expressing a trait change influences (1) its own fitness and the fitness of its current relatives and (2) the fitness of its downstream relatives through modifications of local ecological conditions (i.e., through ecological inheritance). Mathematically, the effects of ecological inheritance on selection are captured by dispersal-limited versions of press perturbations of community ecology. We use our approximation to investigate the evolution of helping within species and harming between species when these behaviors influence demography. We find that altruistic helping evolves more readily when intraspecific competition is for material resources rather than for space, because in this case the costs of kin competition tend to be paid by downstream relatives. Similarly, altruistic harming between species evolves when it alleviates downstream relatives from interspecific competition. Beyond these examples, our approximation can help better understand the influence of ecological inheritance on a variety of eco-evolutionary dynamics in metacommunities, from consumer-resource and predator-prey coevolution to selection on mating systems with demographic feedbacks.}, } @article {pmid30417945, year = {2019}, author = {Thomson, CE and Hadfield, JD}, title = {No evidence for sibling or parent-offspring coadaptation in a wild population of blue tits, despite high power.}, journal = {Evolution; international journal of organic evolution}, volume = {73}, number = {1}, pages = {28-41}, pmid = {30417945}, issn = {1558-5646}, support = {//EPSRC/International ; UF150696//Royal Society/International ; UF100660//Royal Society/International ; NE/F015275/1//Natural Environment Research Council/International ; NE/P000924/1//Natural Environment Research Council/International ; }, mesh = {Animals ; Female ; Male ; *Maternal Behavior ; *Paternal Behavior ; *Reproduction ; *Siblings ; Songbirds/*physiology ; }, abstract = {Parent and offspring behaviors are expected to act as both the agents and targets of selection. This may generate parent-offspring coadaptation in which parent and offspring behaviors become genetically correlated in a way that increases inclusive fitness. Cross-fostering has been used to study parent-offspring coadaptation, with the prediction that offspring raised by non-relatives, or parents raising non-relatives, should suffer fitness costs. Using long-term data from more than 400 partially crossed broods of blue tits (Cyanistes caeruleus), we show that there is no difference in mass or survival between crossed and non-crossed chicks. However, previous studies for which the evidence for parent-offspring coadaptation is strongest compare chicks from fully crossed broods with those from non-crossed broods. When parent-offspring coadaptation acts at the level of the brood then partial cross-fostering experiments are not expected to show evidence of coadaptation. To test this, we performed an additional experiment (163 broods) in which clutches were either fully crossed, non-crossed, or partially crossed. In agreement with the long-term data, there was no evidence for parent-offspring coadaptation on offspring fitness despite high power. In addition there was no evidence of effects on parental fitness, nor evidence of sibling coadaptation, although the power of these tests was more modest.}, } @article {pmid30401742, year = {2018}, author = {Wang, C and Lu, X}, title = {Reply to Engelhardt et al.: Inclusive fitness does maintain a heritable altruism polymorphism in Tibetan ground tits.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {48}, pages = {E11210-E11211}, pmid = {30401742}, issn = {1091-6490}, mesh = {*Altruism ; Game Theory ; *Genetic Fitness ; Tibet ; }, } @article {pmid30397131, year = {2018}, author = {Green, JP and Hatchwell, BJ}, title = {Inclusive fitness consequences of dispersal decisions in a cooperatively breeding bird, the long-tailed tit (Aegithalos caudatus).}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {47}, pages = {12011-12016}, pmid = {30397131}, issn = {1091-6490}, mesh = {Animal Migration/*physiology ; Animals ; Behavior, Animal/physiology ; Biological Evolution ; Breeding ; Cooperative Behavior ; Female ; Gene Flow/physiology ; Male ; Mating Preference, Animal/*physiology ; Passeriformes/physiology ; Population Dynamics ; Reproduction ; Sexual Behavior, Animal/*physiology ; Songbirds/physiology ; }, abstract = {Natal dispersal is a demographic trait with profound evolutionary, ecological, and behavioral consequences. However, our understanding of the adaptive value of dispersal patterns is severely hampered by the difficulty of measuring the relative fitness consequences of alternative dispersal strategies in natural populations. This is especially true in social species, in which natal philopatry allows kin selection to operate, so direct and indirect components of inclusive fitness have to be considered when evaluating selection on dispersal. Here, we use lifetime reproductive success data from a long-term study of a cooperative breeder, the long-tailed tit Aegithalos caudatus, to quantify the direct and indirect components of inclusive fitness. We show that dispersal has a negative effect on the accrual of indirect fitness, and hence inclusive fitness, by males. In contrast, the inclusive, predominantly direct, fitness of females increases with dispersal distance. We conclude that the conflicting fitness consequences of dispersal in this species result in sexually antagonistic selection on this key demographic parameter.}, } @article {pmid30381383, year = {2018}, author = {Macfarlan, SJ and Erickson, PI and Yost, J and Regalado, J and Jaramillo, L and Beckerman, S}, title = {Bands of brothers and in-laws: Waorani warfare, marriage and alliance formation.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1890}, pages = {}, pmid = {30381383}, issn = {1471-2954}, mesh = {Adolescent ; Adult ; Anthropology, Cultural ; Child ; *Cooperative Behavior ; Ecuador ; Family ; Female ; Humans ; Male ; Marriage/*psychology ; Middle Aged ; Warfare/*psychology ; }, abstract = {The root of modern human warfare lies in the lethal coalitionary violence of males in small-scale societies. However, there is a paucity of quantitative data concerning the form and function of coalitionary violence in this setting. Debates exist over how lethal coalitions are constituted, as well as the motivations and benefits for males to join such groups. Data from a lowland Amazonian population, the Waorani of Ecuador, illuminate three issues: (i) the degree to which raiding parties are composed of groups of fraternal kin as opposed to strategic alliances of actual or potential affinal kin; (ii) the extent to which individuals use pre-existing affinal ties to motivate others to participate in war or leverage warfare as a mechanism to create such ties; and (iii) the extent to which participation in raiding is driven by rewards associated with future marriage opportunities. Analyses demonstrate that Waorani raiding parties were composed of a mix of males who were potential affines, actual affines and fraternal kin, suggesting that men used pre-existing genetic, lineal and social kin ties for recruiting raid partners and used raiding as a venue to create novel social relationships. Furthermore, analyses demonstrate that males leveraged raiding alliances to achieve marriage opportunities for themselves as well as for their children. Overall, it appears that a complex set of motivations involving individual rewards, kin marriage opportunities, subtle coercion and the assessment of alliance strength promote violent intergroup conflict among the Waorani. These findings illustrate the complex inter-relationships among kin selection, coalition building and mating success in our species.}, } @article {pmid30381376, year = {2018}, author = {Holen, ØH and Johnstone, RA}, title = {Reciprocal mimicry: kin selection can drive defended prey to resemble their Batesian mimics.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1890}, pages = {}, pmid = {30381376}, issn = {1471-2954}, mesh = {Animals ; *Biological Evolution ; Biological Mimicry/*genetics ; Models, Biological ; *Predatory Behavior ; Selection, Genetic ; }, abstract = {Established mimicry theory predicts that Batesian mimics are selected to resemble their defended models, while models are selected to become dissimilar from their mimics. However, this theory has mainly considered individual selection acting on solitary organisms such as adult butterflies. Although Batesian mimicry of social insects is common, the few existing applications of kin selection theory to mimicry have emphasized relatedness among mimics rather than among models. Here, we present a signal detection model of Batesian mimicry in which the population of defended model prey is kin structured. Our analysis shows for most of parameter space that increased average dissimilarity from mimics has a twofold group-level cost for the model prey: it attracts more predators and these adopt more aggressive attack strategies. When mimetic resemblance and local relatedness are sufficiently high, such costs acting in the local neighbourhood may outweigh the individual benefits of dissimilarity, causing kin selection to drive the models to resemble their mimics. This requires model prey to be more common than mimics and/or well-defended, the conditions under which Batesian mimicry is thought most successful. Local relatedness makes defended prey easier targets for Batesian mimicry and is likely to stabilize the mimetic relationship over time.}, } @article {pmid30380919, year = {2018}, author = {Hernández Blasi, C and Mondéjar, L}, title = {Testing the Kundera Hypothesis: Does Every Woman (But Not Every Man) Prefer Her Child to Her Mate?.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {16}, number = {4}, pages = {1474704918808864}, pmid = {30380919}, issn = {1474-7049}, mesh = {Adult ; *Altruism ; Choice Behavior/*physiology ; Female ; Humans ; *Interpersonal Relations ; Male ; Maternal Behavior/*physiology ; *Morals ; *Parent-Child Relations ; *Sexual Partners ; Young Adult ; }, abstract = {The context of a famous novel by Milan Kundera (Immortality) suggests that when faced with a life-or-death situation, every woman would prefer to save her child than her husband, left hanging whether every man would do the same. We labeled this as the Kundera hypothesis, and the purpose of this study was to test it empirically as we believe it raises a thought-provoking question in evolutionary terms. Specifically, 197 college students (92 women) were presented a questionnaire where they had to make different decisions about four dilemmas about who to save (their mate or their offspring) in two hypothetical life-or-death situations: a home fire and a car crash. These dilemmas involved two different mate ages (a 25- or a 40-year-old mate) and two offspring ages (1- or a 6-year-old child). For comparative purposes, we also included complementary life-or-death dilemmas on both a sibling and an offspring, and a sibling and a cousin. The results generally supported the Kundera hypothesis: Although the majority of men and women made the decision to save their offspring instead of their mate, about 18% of men on average (unlike the 5% of women) consistently decided to save their mate across the four dilemmas in the two life-or-death situations. These data were interpreted with reference to Hamilton's inclusive fitness theory, the preferential role of women as kin keepers, and the evolution of altruism toward friends and mates.}, } @article {pmid30372557, year = {2018}, author = {Fortuna, TM and Namias, A and Snirc, A and Branca, A and Hood, ME and Raquin, C and Shykoff, JA and Giraud, T}, title = {Multiple infections, relatedness and virulence in the anther-smut fungus castrating Saponaria plants.}, journal = {Molecular ecology}, volume = {27}, number = {23}, pages = {4947-4959}, doi = {10.1111/mec.14911}, pmid = {30372557}, issn = {1365-294X}, mesh = {Basidiomycota/*genetics/*pathogenicity ; Flowers/microbiology ; Genetic Variation ; Genotype ; Microsatellite Repeats ; Plant Diseases/*microbiology ; Plant Infertility ; Saponaria/genetics/*microbiology ; Virulence ; }, abstract = {Multiple infections (co-occurrence of multiple pathogen genotypes within an individual host) can have important impacts on diseases. Relatedness among pathogens can affect the likelihood of multiple infections and their consequences through kin selection. Previous studies on the castrating anther-smut fungus Microbotryum lychnidis-dioicae have shown that multiple infections occur in its host plant Silene latifolia. Relatedness was high among fungal genotypes within plants, which could result from competitive exclusion between unrelated fungal genotypes, from population structure or from interactions between plant and fungal genotypes for infection ability. Here, we aimed at disentangling these hypotheses using M. saponariae and its host Saponaria officinalis, both experimentally tractable for these questions. By analysing populations using microsatellite markers, we also found frequent occurrence of multiple infections and high relatedness among strains within host plants. Infections resulting from experimental inoculations in the greenhouse also revealed high relatedness among strains co-infecting host plants, even in clonally replicated plant genotypes, indicating that high relatedness within plants did not result merely from plant x fungus interactions or population structure. Furthermore, hyphal growth in vitro was affected by the presence of a competitor growing nearby and by its genetic similarity, although this latter effect was strain-dependent. Altogether, our results support the hypothesis that relatedness-dependent competitive exclusion occurs in Microbotryum fungi within plants. These microorganisms can thus respond to competitors and to their level of relatedness.}, } @article {pmid30359363, year = {2018}, author = {Dos Santos, M and Ghoul, M and West, SA}, title = {Pleiotropy, cooperation, and the social evolution of genetic architecture.}, journal = {PLoS biology}, volume = {16}, number = {10}, pages = {e2006671}, pmid = {30359363}, issn = {1545-7885}, mesh = {Computer Simulation ; *Evolution, Molecular ; *Genetic Pleiotropy/physiology ; Genotype ; Microbial Interactions/*genetics/physiology ; Microbiota/*genetics/physiology ; *Models, Genetic ; Mutation ; }, abstract = {Pleiotropy has been suggested as a novel mechanism for stabilising cooperation in bacteria and other microbes. The hypothesis is that linking cooperation with a trait that provides a personal (private) benefit can outweigh the cost of cooperation in situations when cooperation would not be favoured by mechanisms such as kin selection. We analysed the theoretical plausibility of this hypothesis, with analytical models and individual-based simulations. We found that (1) pleiotropy does not stabilise cooperation, unless the cooperative and private traits are linked via a genetic architecture that cannot evolve (mutational constraint); (2) if the genetic architecture is constrained in this way, then pleiotropy favours any type of trait and not especially cooperation; (3) if the genetic architecture can evolve, then pleiotropy does not favour cooperation; and (4) there are several alternative explanations for why traits may be linked, and causality can even be predicted in the opposite direction, with cooperation favouring pleiotropy. Our results suggest that pleiotropy could only explain cooperation under restrictive conditions and instead show how social evolution can shape the genetic architecture.}, } @article {pmid30353655, year = {2019}, author = {Li, XY and Kokko, H}, title = {Sex-biased dispersal: a review of the theory.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {94}, number = {2}, pages = {721-736}, pmid = {30353655}, issn = {1469-185X}, mesh = {Animal Distribution/*physiology ; Animals ; Biological Evolution ; Female ; Genetic Fitness ; Inbreeding ; Male ; *Sex Characteristics ; Sex Factors ; Sex Ratio ; Sexual Behavior, Animal ; }, abstract = {Dispersal is ubiquitous throughout the tree of life: factors selecting for dispersal include kin competition, inbreeding avoidance and spatiotemporal variation in resources or habitat suitability. These factors differ in whether they promote male and female dispersal equally strongly, and often selection on dispersal of one sex depends on how much the other disperses. For example, for inbreeding avoidance it can be sufficient that one sex disperses away from the natal site. Attempts to understand sex-specific dispersal evolution have created a rich body of theoretical literature, which we review here. We highlight an interesting gap between empirical and theoretical literature. The former associates different patterns of sex-biased dispersal with mating systems, such as female-biased dispersal in monogamous birds and male-biased dispersal in polygynous mammals. The predominant explanation is traceable back to Greenwood's () ideas of how successful philopatric or dispersing individuals are at gaining mates or the resources required to attract them. Theory, however, has developed surprisingly independently of these ideas: models typically track how immigration and emigration change relatedness patterns and alter competition for limiting resources. The limiting resources are often considered sexually distinct, with breeding sites and fertilizable females limiting reproductive success for females and males, respectively. We show that the link between mating system and sex-biased dispersal is far from resolved: there are studies showing that mating systems matter, but the oft-stated association between polygyny and male-biased dispersal is not a straightforward theoretical expectation. Here, an important understudied factor is the extent to which movement is interpretable as an extension of mate-searching (e.g. are matings possible en route or do they only happen after settling in new habitat - or can females perhaps move with stored sperm). We also point out other new directions for bridging the gap between empirical and theoretical studies: there is a need to build Greenwood's influential yet verbal explanation into formal models, which also includes the possibility that an individual benefits from mobility as it leads to fitness gains in more than one final breeding location (a possibility not present in models with a very rigid deme structure). The order of life-cycle events is likewise important, as this impacts whether a departing individual leaves behind important resources for its female or male kin, or perhaps both, in the case of partially overlapping resource use.}, } @article {pmid30338460, year = {2019}, author = {Amici, F}, title = {Memories of emotional expressions in horses.}, journal = {Learning & behavior}, volume = {47}, number = {3}, pages = {191-192}, pmid = {30338460}, issn = {1543-4508}, mesh = {Animals ; Attention ; Horses ; Humans ; Interpersonal Relations ; *Memory ; *Mental Recall ; }, abstract = {Proops, Grounds, Smith, and McComb (2018) suggest that horses remember previous emotional expressions of specific humans, and use these memories to adjust their behavior in future social interactions. Despite some methodological shortcomings, this study raises important questions on the complexity of social interactions in nonhuman animals, which surely deserve further attention.}, } @article {pmid30320554, year = {2018}, author = {van Veelen, M}, title = {Can Hamilton's rule be violated?.}, journal = {eLife}, volume = {7}, number = {}, pages = {}, pmid = {30320554}, issn = {2050-084X}, mesh = {*Altruism ; *Models, Biological ; *Models, Statistical ; }, abstract = {How generally Hamilton's rule holds is a much debated question. The answer to that question depends on how costs and benefits are defined. When using the regression method to define costs and benefits, there is no scope for violations of Hamilton's rule. We introduce a general model for assortative group compositions to show that, when using the counterfactual method for computing costs and benefits, there is room for violations. The model also shows that there are limitations to observing violations in equilibrium, as the discrepancies between Hamilton's rule and the direction of selection may imply that selection will take the population out of the region of disagreement, precluding observations of violations in equilibrium. Given what it takes to create a violation, empirical tests of Hamilton's rule, both in and out of equilibrium, require the use of statistical models that allow for identifying non-linearities in the fitness function.}, } @article {pmid30310732, year = {2018}, author = {Rodrigues, AMM}, title = {Resource availability and adjustment of social behaviour influence patterns of inequality and productivity across societies.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e5488}, pmid = {30310732}, issn = {2167-8359}, abstract = {Animal societies vary widely in the diversity of social behaviour and the distribution of reproductive shares among their group members. It has been shown that individual condition can lead to divergent social roles and that social specialisation can cause an exacerbation or a mitigation of the inequality among group members within a society. This work, however, has not investigated cases in which resource availability varies between different societies, a factor that is thought to explain variation in the level of cooperation and the disparities in reproductive shares within each social group. In this study, I focus on how resource availability mediates the expression of social behaviour and how this, in turn, mediates inequality both within and between groups. I find that when differences in resource availability between societies persist over time, resource-rich societies become more egalitarian. Because lower inequality improves the productivity of a society, the inequality between resource-rich and resource-poor societies rises. When resource availability fluctuates over time, resource-rich societies tend to become more unequal. Because inequality hinders the productivity of a society, the inequality between resource-rich and resource-poor societies falls. From the evolutionary standpoint, my results show that spatial and temporal variation in resource availability may exert a strong influence on the level of inequality both within and between societies.}, } @article {pmid30306126, year = {2018}, author = {Ohkubo, Y and Yamamoto, T and Ogusu, N and Watanabe, S and Murakami, Y and Yagi, N and Hasegawa, E}, title = {The benefits of grouping as a main driver of social evolution in a halictine bee.}, journal = {Science advances}, volume = {4}, number = {10}, pages = {e1700741}, pmid = {30306126}, issn = {2375-2548}, mesh = {Animals ; Bees ; Behavior, Animal/*physiology ; Diploidy ; Female ; Flight, Animal ; Genetic Fitness ; Haploidy ; Japan ; Male ; Models, Biological ; Nesting Behavior ; *Social Behavior ; Time Factors ; }, abstract = {Over the past decade, the cause of sociality has been much debated. Inclusive fitness [br in Hamilton's rule (br - c > 0)] has been criticized but is still useful in the organization of a framework by elucidating mechanisms through which br (benefit × relatedness) becomes larger than c (cost). The bee Lasioglossum baleicum is suitable for investigation of this issue because of the sympatric occurrence of both social and solitary nesting in its populations. We show that a large part (approximately 92%) of the inclusive fitness of a eusocial worker can be attributed to the benefits of grouping. A 1.5-fold relatedness asymmetry benefit in singly mated haplo-diploids explains a small part (approximately 8.5%) of the observed inclusive fitness. Sociality enables this species to conduct foraging and nest defense simultaneously, which is not the case in solitary nests. Our results indicate that this benefit of grouping is the main source of the increased inclusive fitness of eusocial workers.}, } @article {pmid30305461, year = {2018}, author = {Dyble, M and Gardner, A and Vinicius, L and Migliano, AB}, title = {Inclusive fitness for in-laws.}, journal = {Biology letters}, volume = {14}, number = {10}, pages = {}, pmid = {30305461}, issn = {1744-957X}, mesh = {Altruism ; Cooperative Behavior ; *Family ; Female ; *Genetic Fitness ; Humans ; Male ; Reproduction ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Cooperation among kin is common across the natural world and can be explained in terms of inclusive fitness theory, which holds that individuals can derive indirect fitness benefits from aiding genetically related individuals. However, human kinship includes not only genetic kin but also kin by marriage: our affines (in-laws) and spouses. Can cooperation between these genetically unrelated kin be reconciled with inclusive fitness theory? Here, we argue that although affinal kin and spouses do not necessarily share genetic ancestry, they may have shared genetic interests in future reproduction and, as such, can derive indirect fitness benefits though cooperating. We use standard inclusive fitness theory to derive a coefficient of shared reproductive interest (s) that predicts altruistic investment both in genetic kin and in spouses and affines. Specifically, a behaviour that reduces the fitness of the actor by c and increases the fitness of the recipient by b will be favoured by natural selection when sb > c We suggest that the coefficient of shared reproductive interest may provide a valuable tool for understanding not only the evolution of human kinship but also cooperation and conflict across the natural world more generally.}, } @article {pmid30272235, year = {2018}, author = {Minkner, MMI and Young, C and Amici, F and McFarland, R and Barrett, L and Grobler, JP and Henzi, SP and Widdig, A}, title = {Assessment of Male Reproductive Skew via Highly Polymorphic STR Markers in Wild Vervet Monkeys, Chlorocebus pygerythrus.}, journal = {The Journal of heredity}, volume = {109}, number = {7}, pages = {780-790}, doi = {10.1093/jhered/esy048}, pmid = {30272235}, issn = {1465-7333}, mesh = {Animals ; Chlorocebus aethiops/*genetics/*physiology ; Female ; *Genetic Markers ; Heterozygote ; Male ; Microsatellite Repeats/*genetics ; *Polymorphism, Genetic ; Reproduction/*genetics ; Seasons ; South Africa ; }, abstract = {Male reproductive strategies have been well studied in primate species where the ability of males to monopolize reproductive access is high. Less is known about species where males cannot monopolize mating access. Vervet monkeys (Chlorocebus pygerythrus) are interesting in this regard as female codominance reduces the potential for male monopolization. Under this condition, we assessed whether male dominance rank still influences male mating and reproductive success, by assigning paternities to infants in a population of wild vervets in the Eastern Cape, South Africa. To determine paternity, we established microsatellite markers from noninvasive fecal samples via cross-species amplification. In addition, we evaluated male mating and reproductive success for 3 groups over 4 mating seasons. We identified 21 highly polymorphic microsatellites (number of alleles = 7.5 ± 3.1 [mean ± SD], observed heterozygosity = 0.691 ± 0.138 [mean ± SD]) and assigned paternity to 94 of 97 sampled infants (96.9%) with high confidence. Matings pooled over 4 seasons were significantly skewed across 3 groups, although skew indices were low (B index = 0.023-0.030) and mating success did not correlate with male dominance. Paternities pooled over 4 seasons were not consistently significantly skewed (B index = 0.005-0.062), with high-ranking males siring more offspring than subordinates only in some seasons. We detected 6 cases of extra-group paternity (6.4%) and 4 cases of natal breeding (4.3%). Our results suggest that alternative reproductive strategies besides priority of access for dominant males are likely to affect paternity success, warranting further investigation into the determinants of paternity among species with limited male monopolization potential.}, } @article {pmid30225081, year = {2018}, author = {Konrad, CM and Gero, S and Frasier, T and Whitehead, H}, title = {Kinship influences sperm whale social organization within, but generally not among, social units.}, journal = {Royal Society open science}, volume = {5}, number = {8}, pages = {180914}, pmid = {30225081}, issn = {2054-5703}, abstract = {Sperm whales have a multi-level social structure based upon long-term, cooperative social units. What role kinship plays in structuring this society is poorly understood. We combined extensive association data (518 days, during 2005-2016) and genetic data (18 microsatellites and 346 bp mitochondrial DNA (mtDNA) control region sequences) for 65 individuals from 12 social units from the Eastern Caribbean to examine patterns of kinship and social behaviour. Social units were clearly matrilineally based, evidenced by greater relatedness within social units (mean r = 0.14) than between them (mean r = 0.00) and uniform mtDNA haplotypes within social units. Additionally, most individuals (82.5%) had a first-degree relative in their social unit, while we found no first-degree relatives between social units. Generally and within social units, individuals associated more with their closer relatives (matrix correlations: 0.18-0.25). However, excepting a highly related pair of social units that merged over the study period, associations between social units were not correlated with kinship (p > 0.1). These results are the first to robustly demonstrate kinship's contribution to social unit composition and association preferences, though they also reveal variability in association preferences that is unexplained by kinship. Comparisons with other matrilineal species highlight the range of possible matrilineal societies and how they can vary between and even within species.}, } @article {pmid30222228, year = {2019}, author = {Townsend, AK and Taff, CC and Jones, ML and Getman, KH and Wheeler, SS and Hinton, MG and Logsdon, RM}, title = {Apparent inbreeding preference despite inbreeding depression in the American crow.}, journal = {Molecular ecology}, volume = {28}, number = {5}, pages = {1116-1126}, doi = {10.1111/mec.14866}, pmid = {30222228}, issn = {1365-294X}, support = {(13-2735)//ANR Competitive Grant from the University of California at Davis/International ; 1555754//National Science Foundation/International ; }, mesh = {Animals ; California ; Crows/*genetics/physiology ; Heterozygote ; Inbreeding ; Inbreeding Depression/*genetics ; Microsatellite Repeats/*genetics ; New York ; Reproduction/*genetics ; Sexual Behavior, Animal ; }, abstract = {Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York, and Davis, California, USA) of the cooperatively breeding American crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: The observed heterozygosity among 396 sampled crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassortative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression.}, } @article {pmid30210320, year = {2018}, author = {Neupert, S and Hornung, M and Grenwille Millar, J and Kleineidam, CJ}, title = {Learning Distinct Chemical Labels of Nestmates in Ants.}, journal = {Frontiers in behavioral neuroscience}, volume = {12}, number = {}, pages = {191}, pmid = {30210320}, issn = {1662-5153}, abstract = {Colony coherence is essential for eusocial insects because it supports the inclusive fitness of colony members. Ants quickly and reliably recognize who belongs to the colony (nestmates) and who is an outsider (non-nestmates) based on chemical recognition cues (cuticular hydrocarbons: CHCs) which as a whole constitute a chemical label. The process of nestmate recognition often is described as matching a neural template with the label. In this study, we tested the prevailing view that ants use commonalities in the colony odor that are present in the CHC profile of all individuals of a colony or whether different CHC profiles are learned independently. We created and manipulated sub-colonies by adding one or two different hydrocarbons that were not present in the original colony odor of our Camponotus floridanus colony and later tested workers of the sub-colonies in one-on-one encounters for aggressive responses. We found that workers adjust their nestmate recognition by learning novel, manipulated CHC profiles, but still accept workers with the previous CHC profile. Workers from a sub-colony with two additional components showed aggression against workers with only one of the two components added to their CHC profile. Thus, additional components as well as the lack of a component can alter a label as "non-nestmate." Our results suggest that ants have multiple-templates to recognize nestmates carrying distinct labels. This finding is in contrast to what previously has been proposed, i.e., a widening of the acceptance range of one template. We conclude that nestmate recognition in ants is a partitioned (multiple-template) process of the olfactory system that allows discrimination and categorization of nestmates by differences in their CHC profiles. Our findings have strong implications for our understanding of the underlying mechanisms of colony coherence and task allocation because they illustrate the importance of individual experience and task associated differences in the CHC profiles that can be instructive for the organization of insect societies.}, } @article {pmid30209226, year = {2018}, author = {Kazem, AJN and Barth, Y and Pfefferle, D and Kulik, L and Widdig, A}, title = {Parent-offspring facial resemblance increases with age in rhesus macaques.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1886}, pages = {}, pmid = {30209226}, issn = {1471-2954}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Age Factors ; Animals ; Cues ; *Face ; Female ; Humans ; Macaca mulatta/*physiology ; Male ; *Phenotype ; *Visual Perception ; }, abstract = {Kin recognition is a key ability which facilitates the acquisition of inclusive fitness benefits and enables optimal outbreeding. In primates, phenotype matching is considered particularly important for the recognition of patrilineal relatives, as information on paternity is unlikely to be available via social familiarity. Phenotypic cues to both paternal and maternal relatedness exist in the facial features of humans and other primates. However, theoretical models suggest that in systems with uncertainty parentage it may be adaptive for offspring to conceal such cues when young, in order to avoid potential costs of being discriminated against by unrelated adults. Using experienced human raters, we demonstrate in a computer-based task that detection of parent-offspring resemblances in the faces of rhesus macaques (Macaca mulatta) increases significantly with offspring age. Moreover, this effect is specific to information about kinship, as raters were extremely successful at discriminating individuals even among the youngest animals. To our knowledge, this is the first evidence in non-humans for the age-dependent expression of visual cues used in kin recognition.}, } @article {pmid30165602, year = {2019}, author = {Bawa, KS and Ingty, T and Revell, LJ and Shivaprakash, KN}, title = {Correlated evolution of flower size and seed number in flowering plants (monocotyledons).}, journal = {Annals of botany}, volume = {123}, number = {1}, pages = {181-190}, pmid = {30165602}, issn = {1095-8290}, mesh = {*Biological Evolution ; Flowers/*anatomy & histology/growth & development ; Magnoliopsida/*anatomy & histology/growth & development/*physiology ; Phylogeny ; Seeds/*physiology ; }, abstract = {BACKGROUND AND AIMS: Kin selection theory predicts that a parent may minimize deleterious effects of competition among seeds developing within ovaries by increasing the genetic relatedness of seeds within an ovary. Alternatively, the number of developing seeds could be reduced to one or a few. It has also been suggested that single or few seeded fruits may be correlated with small flowers, and multi-ovulate ovaries or many seeded fruits may be associated with large flowers with specialized pollination mechanisms. We examined the correlation between flower size and seed number in 69 families of monocotyledons to assess if correlations are significant and independent of phylogeny.

METHODS: We first examined the effect of phylogenetic history on the evolution of these two traits, flower size and seed number, and then mapped correlations between them on the latest phylogenetic tree of monocotyledons.

RESULTS: The results provide phylogenetically robust evidence of strong correlated evolution between flower size and seed number and show that correlated evolution of traits is not constrained by phylogenetic history of taxa. Moreover, the two character combinations, small flowers and a single or few seeds per fruit, and large flowers and many seeded fruits, have persisted in monocotyledons longer than other trait combinations.

CONCLUSIONS: The analyses support the suggestion that most angiosperms may fall into two categories, one with large flowers and many seeded fruits and the other with small flowers and single or few seeded fruits, and kin selection within ovaries may explain the observed patterns.}, } @article {pmid30135160, year = {2018}, author = {Downing, PA and Griffin, AS and Cornwallis, CK}, title = {Sex differences in helping effort reveal the effect of future reproduction on cooperative behaviour in birds.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1885}, pages = {}, pmid = {30135160}, issn = {1471-2954}, mesh = {Animals ; Birds/*physiology ; Cooperative Behavior ; Female ; Helping Behavior ; Male ; *Nesting Behavior ; *Reproduction ; Sex Characteristics ; }, abstract = {The evolution of helping behaviour in species that breed cooperatively in family groups is typically attributed to kin selection alone. However, in many species, helpers go on to inherit breeding positions in their natal groups, but the extent to which this contributes to selection for helping is unclear as the future reproductive success of helpers is often unknown. To quantify the role of future reproduction in the evolution of helping, we compared the helping effort of female and male retained offspring across cooperative birds. The kin selected benefits of helping are equivalent between female and male helpers-they are equally related to the younger siblings they help raise-but the future reproductive benefits of helping differ because of sex differences in the likelihood of breeding in the natal group. We found that the sex which is more likely to breed in its natal group invests more in helping, suggesting that in addition to kin selection, helping in family groups is shaped by future reproduction.}, } @article {pmid30108624, year = {2018}, author = {Ren, Y and Huang, K and Guo, S and Pan, R and Derek, DW and Qi, X and Wang, X and Wang, C and Zhao, H and Yang, B and Li, F and Li, B}, title = {Kinship promotes affiliative behaviors in a monkey.}, journal = {Current zoology}, volume = {64}, number = {4}, pages = {441-447}, pmid = {30108624}, issn = {1674-5507}, abstract = {In social mammals, kinship is an important factor that often affects the interactions among individuals within groups. In primates that live in a multilevel society, kinship may affect affiliative patterns between individuals at different scales within the larger group. For this study, we use field observations and molecular methods to reveal the profiles of how kinship affects affiliative behaviors between individuals in a breeding band of wild golden snub-nosed monkeys (Rhinopithecus roxellana). We use a novel nonparametric test, the partition Mantel test, to measure independently the correlation between kinship and each of three affiliative behaviors. Our results show that more closely related females are more likely to groom each other. Average relatedness between adult females within the same one-male unit (OMU) is higher than that between adult females from different OMUs. We suggest that closely related females may reside in the same OMU in order to attain inclusive fitness benefits, and that kinship plays an important role in maintaining the social structure of this species.}, } @article {pmid30080237, year = {2018}, author = {D'Aloia, CC and Neubert, MG}, title = {The formation of marine kin structure: effects of dispersal, larval cohesion, and variable reproductive success.}, journal = {Ecology}, volume = {99}, number = {10}, pages = {2374-2384}, doi = {10.1002/ecy.2480}, pmid = {30080237}, issn = {0012-9658}, support = {DEB-1558904//US NSF/International ; }, mesh = {Animals ; *Genetics, Population ; Inbreeding ; Larva ; *Reproduction ; }, abstract = {The spatial distribution of relatives has profound effects on kin interactions, inbreeding, and inclusive fitness. Yet, in the marine environment, the processes that generate patterns of kin structure remain understudied because larval dispersal on ocean currents was historically assumed to disrupt kin associations. Recent genetic evidence of co-occurring siblings challenges this assumption and raises the intriguing question of how siblings are found together after a (potentially) disruptive larval phase. Here, we develop individual-based models to explore how stochastic processes operating at the individual level affect expected kinship at equilibrium. Specifically, we predict how limited dispersal, sibling cohesion, and variability in reproductive success differentially affect patterns of kin structure. All three mechanisms increase mean kinship within populations, but their spatial effects are markedly different. We find that (1) when dispersal is limited, kinship declines monotonically as a function of the distance between individuals; (2) when siblings disperse cohesively, kinship increases within a site relative to between sites; and (3) when reproductive success varies, kinship increases equally at all distances. The differential effects of these processes therefore only become apparent when individuals are sampled at multiple spatial scales. Notably, our models suggest that aggregative larval behaviors, such as sibling cohesion, are not necessary to explain documented levels of relatedness within marine populations. Together, these findings establish a theoretical framework for disentangling the drivers of marine kin structure.}, } @article {pmid30073752, year = {2019}, author = {Andersson, M and Åhlund, M and Waldeck, P}, title = {Brood parasitism, relatedness and sociality: a kinship role in female reproductive tactics.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {94}, number = {1}, pages = {307-327}, doi = {10.1111/brv.12455}, pmid = {30073752}, issn = {1469-185X}, abstract = {Conspecific brood parasitism (CBP) is a reproductive tactic in which parasitic females lay eggs in nests of other females of the same species that then raise the joint brood. Parasites benefit by increased reproduction, without costs of parental care for the parasitic eggs. CBP occurs in many egg-laying animals, among birds most often in species with large clutches and self-feeding young: two major factors facilitating successful parasitism. CBP is particularly common in waterfowl (Anatidae), a group with female-biased natal philopatry and locally related females. Theory suggests that relatedness between host and parasite can lead to inclusive fitness benefits for both, but if host costs are high, parasites should instead target unrelated females. Pairwise relatedness (r) in host-parasite (h-p) pairs of females has been estimated using molecular genetic methods in seven waterfowl (10 studies). In many h-p pairs, the two females were unrelated (with low r, near the local population mean). However, close relatives (r = 0.5) were over-represented in h-p pairs, which in all 10 studies had higher mean relatedness than other females. In one species where this was studied, h-p relatedness was higher than between nesting close neighbours, and hosts parasitized by non-relatives aggressively rejected other females. In another species, birth nest-mates (mother-daughters, sisters) associated in the breeding area as adults, and became h-p pairs more often than expected by chance. These and other results point to recognition of birth nest-mates and perhaps other close relatives. For small to medium host clutch sizes, addition of a few parasitic eggs need not reduce host offspring success. Estimates in two species suggest that hosts can then gain inclusive fitness if parasitized by relatives. Other evidence of female cooperation is incubation by old eider Somateria mollissima females of clutches laid by their relatives, and merging and joint care of broods of young. Merging females tended to be more closely related. Eiders associate with kin in many situations, and in some geese and swans, related females may associate over many years. Recent genetic evidence shows that also New World quails (Odontophoridae) have female-biased natal philopatry, CBP and brood merging, inviting further study and comparison with waterfowl. Kin-related parasitism also occurs in some insects, with revealing parallels and differences compared to birds. In hemipteran bugs, receiving extra eggs is beneficial for hosts by diluting offspring predation. In eggplant lace bugs Gargaphia solani, host and parasite are closely related, and kin selection favours egg donation to related females. Further studies of kinship in CBP, brood merging and other contexts can test if some of these species are socially more advanced than presently known.}, } @article {pmid30059691, year = {2018}, author = {Gleichsner, AM and Reinhart, K and Minchella, DJ}, title = {Of mice and worms: are co-infections with unrelated parasite strains more damaging to definitive hosts?.}, journal = {International journal for parasitology}, volume = {48}, number = {11}, pages = {881-885}, doi = {10.1016/j.ijpara.2018.05.004}, pmid = {30059691}, issn = {1879-0135}, mesh = {Animals ; Biomphalaria/*parasitology ; *Coinfection ; Host-Parasite Interactions ; Humans ; Mice ; Schistosoma mansoni/*classification/genetics/pathogenicity/physiology ; Schistosomiasis mansoni/*parasitology ; Virulence ; }, abstract = {Intraspecific competition between co-infecting parasites can influence the amount of virulence, or damage, they do to their host. Kin selection theory dictates that infections with related parasite individuals should have lower virulence than infections with unrelated individuals, because they benefit from inclusive fitness and increased host longevity. These predictions have been tested in a variety of microparasite systems, and in larval stage macroparasites within intermediate hosts, but the influence of adult macroparasite relatedness on virulence has not been investigated in definitive hosts. This study used the human parasite Schistosoma mansoni to determine whether definitive hosts infected with related parasites experience lower virulence than hosts infected with unrelated parasites, and to compare the results from intermediate host studies in this system. The presence of unrelated parasites in an infection decreased parasite infectivity, the ability of a parasite to infect a definitive host, and total worm establishment in hosts, impacting the less virulent parasite strain more severely. Unrelated parasite co-infections had similar virulence to the more virulent of the two parasite strains. We combine these findings with complementary studies of the intermediate snail host and describe trade-offs in virulence and selection within the life cycle. Damage to the host by the dominant strain was muted by the presence of a competitor in the intermediate host, but was largely unaffected in the definitive host. Our results in this host-parasite system suggest that unrelated infections may select for higher virulence in definitive hosts while selecting for lower virulence in intermediate hosts.}, } @article {pmid30055104, year = {2019}, author = {Espinosa, A and Paz-Y-Miño-C, G}, title = {Discrimination Experiments in Entamoeba and Evidence from Other Protists Suggest Pathogenic Amebas Cooperate with Kin to Colonize Hosts and Deter Rivals.}, journal = {The Journal of eukaryotic microbiology}, volume = {66}, number = {2}, pages = {354-368}, pmid = {30055104}, issn = {1550-7408}, support = {P20 GM103430/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Entamoeba/*physiology ; Entamoebiasis/parasitology ; *Microbial Interactions ; Species Specificity ; }, abstract = {Entamoeba histolytica is one of the least understood protists in terms of taxa, clone, and kin discrimination/recognition ability. However, the capacity to tell apart same or self (clone/kin) from different or nonself (nonclone/nonkin) has long been demonstrated in pathogenic eukaryotes like Trypanosoma and Plasmodium, free-living social amebas (Dictyostelium, Polysphondylium), budding yeast (Saccharomyces), and in numerous bacteria and archaea (prokaryotes). Kin discrimination/recognition is explained under inclusive fitness theory; that is, the reproductive advantage that genetically closely related organisms (kin) can gain by cooperating preferably with one another (rather than with distantly related or unrelated individuals), minimizing antagonism and competition with kin, and excluding genetic strangers (or cheaters = noncooperators that benefit from others' investments in altruistic cooperation). In this review, we rely on the outcomes of in vitro pairwise discrimination/recognition encounters between seven Entamoeba lineages to discuss the biological significance of taxa, clone, and kin discrimination/recognition in a range of generalist and specialist species (close or distantly related phylogenetically). We then focus our discussion on the importance of these laboratory observations for E. histolytica's life cycle, host infestation, and implications of these features of the amebas' natural history for human health (including mitigation of amebiasis).}, } @article {pmid29998471, year = {2019}, author = {Minorsky, PV}, title = {The functions of foliar nyctinasty: a review and hypothesis.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {94}, number = {1}, pages = {216-229}, pmid = {29998471}, issn = {1469-185X}, abstract = {Foliar nyctinasty is a plant behaviour characterised by a pronounced daily oscillation in leaf orientation. During the day, the blades of nyctinastic plant leaves (or leaflets) assume a more or less horizontal position that optimises their ability to capture sunlight for photosynthesis. At night, the positions that the leaf blades assume, regardless of whether they arise by rising, falling or twisting, are essentially vertical. Among the ideas put forth to explain the raison d'être of foliar nyctinasty are that it: (i) improves the temperature relations of plants; (ii) helps remove surface water from foliage; (iii) prevents the disruption of photoperiodism by moonlight; and (iv) directly discourages insect herbivory. After discussing these previous hypotheses, a novel tritrophic hypothesis is introduced that proposes that foliar nyctinasty constitutes an indirect plant defence against nocturnal herbivores. It is suggested that the reduction in physical clutter that follows from nocturnal leaf closure may increase the foraging success of many types of animals that prey upon or parasitise herbivores. Predators and parasitoids generally use some combination of visual, auditory or olfactory cues to detect prey. In terrestrial environments, it is hypothesised that the vertical orientation of the blades of nyctinastic plants at night would be especially beneficial to flying nocturnal predators (e.g. bats and owls) and parasitoids whose modus operandi is death from above. The movements of prey beneath a plant with vertically oriented foliage would be visually more obvious to gleaning or swooping predators under nocturnal or crepuscular conditions. Such predators could also detect sounds made by prey better without baffling layers of foliage overhead to damp and disperse the signal. Moreover, any volatiles released by the prey would diffuse more directly to the awaiting olfactory apparatus of the predators or parasitoids. In addition to facilitating the demise of herbivores by carnivores and parasitoids, foliar nyctinasty, much like the enhanced illumination of the full moon, may mitigate feeding by nocturnal herbivores by altering their foraging behaviour. Foliar nyctinasty could also provide a competitive advantage by encouraging herbivores, seeking more cover, to forage on or around non-nyctinastic species. As an added advantage, foliar nyctinasty, by decreasing the temperature between plants through its effects on re-radiation, may slow certain types of ectothermic herbivores making them more vulnerable to predation. Foliar nyctinasty also may not solely be a behavioural adaptation against folivores; by discouraging foraging by granivores, the inclusive fitness of nyctinastic plants may be increased.}, } @article {pmid29943825, year = {2018}, author = {Bovet, J and Raiber, E and Ren, W and Wang, C and Seabright, P}, title = {Parent-offspring conflict over mate choice: An experimental study in China.}, journal = {British journal of psychology (London, England : 1953)}, volume = {109}, number = {4}, pages = {674-693}, doi = {10.1111/bjop.12319}, pmid = {29943825}, issn = {2044-8295}, support = {71540032//National Natural Science Foundation of China/ ; //ANR - Labex IAST/ ; }, mesh = {Adult ; China ; *Family Conflict ; Female ; Humans ; Male ; Marriage/*psychology ; *Parent-Child Relations ; Parents ; Young Adult ; }, abstract = {Both parents and offspring have evolved mating preferences that enable them to select mates and children-in-law to maximize their inclusive fitness. The theory of parent-offspring conflict predicts that preferences for potential mates may differ between parents and offspring: individuals are expected to value biological quality more in their own mates than in their offspring's mates and to value investment potential more in their offspring's mates than in their own mates. We tested this hypothesis in China using a naturalistic 'marriage market' where parents actively search for marital partners for their offspring. Parents gather at a public park to advertise the characteristics of their adult children, looking for a potential son or daughter-in-law. We presented 589 parents and young adults from the city of Kunming (Yunnan, China) with hypothetical mating candidates varying in their levels of income (proxy for investment potential) and physical attractiveness (proxy for biological quality). We found some evidence of a parent-offspring conflict over mate choice, but only in the case of daughters, who evaluated physical attractiveness as more important than parents. We also found an effect of the mating candidate's sex, as physical attractiveness was deemed more valuable in a female potential mate by parents and offspring alike.}, } @article {pmid29924339, year = {2018}, author = {Piekarski, PK and Carpenter, JM and Lemmon, AR and Moriarty Lemmon, E and Sharanowski, BJ}, title = {Phylogenomic Evidence Overturns Current Conceptions of Social Evolution in Wasps (Vespidae).}, journal = {Molecular biology and evolution}, volume = {35}, number = {9}, pages = {2097-2109}, pmid = {29924339}, issn = {1537-1719}, mesh = {Animals ; *Biological Evolution ; Female ; Nesting Behavior ; *Social Behavior ; Wasps/*genetics ; }, abstract = {The hypothesis that eusociality originated once in Vespidae has shaped interpretation of social evolution for decades and has driven the supposition that preimaginal morphophysiological differences between castes were absent at the outset of eusociality. Many researchers also consider casteless nest-sharing an antecedent to eusociality. Together, these ideas endorse a stepwise progression of social evolution in wasps (solitary → casteless nest-sharing → eusociality with rudimentary behavioral castes → eusociality with preimaginal caste-biasing (PCB) → morphologically differentiated castes). Here, we infer the phylogeny of Vespidae using sequence data generated via anchored hybrid enrichment from 378 loci across 136 vespid species and perform ancestral state reconstructions to test whether rudimentary and monomorphic castes characterized the initial stages of eusocial evolution. Our results reject the single origin of eusociality hypothesis, contest the supposition that eusociality emerged from a casteless nest-sharing ancestor, and suggest that eusociality in Polistinae + Vespinae began with castes having morphological differences. An abrupt appearance of castes with ontogenetically established morphophysiological differences conflicts with the current conception of stepwise social evolution and suggests that the climb up the ladder of sociality does not occur through sequential mutation. Phenotypic plasticity and standing genetic variation could explain how cooperative brood care evolved in concert with nest-sharing and how morphologically dissimilar castes arose without a rudimentary intermediate. Furthermore, PCB at the outset of eusociality implicates a subsocial route to eusociality in Polistinae + Vespinae, emphasizing the role of mother-daughter interactions and subfertility (i.e. the cost component of kin selection) in the origin of workers.}, } @article {pmid29904961, year = {2018}, author = {Rodrigues, AMM}, title = {Demography, life history and the evolution of age-dependent social behaviour.}, journal = {Journal of evolutionary biology}, volume = {31}, number = {9}, pages = {1340-1353}, doi = {10.1111/jeb.13308}, pmid = {29904961}, issn = {1420-9101}, mesh = {*Aging ; Biological Evolution ; *Cooperative Behavior ; Fertility ; *Models, Biological ; Phenotype ; *Social Behavior ; }, abstract = {Since the inception of modern social evolution theory, a vast majority of studies have sought to explain cooperation using relatedness-driven hypotheses. Natural populations, however, show a substantial amount of variation in social behaviour that is uncorrelated with relatedness. Age offers a major alternative explanation for variation in behaviour that remains unaccounted for. Most natural populations are structured into age-classes, with ageing being a nearly universal feature of most major taxa, including eukaryotic and prokaryotic organisms. Despite this, the theoretical underpinnings of age-dependent social behaviour remain limited. Here, I investigate how group age-composition, demography and life history shape trajectories of age-dependent behaviours that are expressed conditionally on an actor and recipient's age. I show that demography introduces novel age-dependent selective pressures acting on social phenotypes. Furthermore, I find that life history traits influence the costs and benefits of cooperation directly, but also indirectly. Life history has a strong impact not only on the genetic structure of the population but also on the distribution of group age-compositions, with both of these processes influencing the expression of age-dependent cooperation. Age of peak reproductive performance, in particular, is of chief importance for the evolution of cooperation, as this will largely determine the age and relatedness of social partners. Moreover, my results suggest that later-life reproductive senescence may occur because of demographic effects alone, which opens new vistas on the evolution of menopause and related phenomena.}, } @article {pmid29892408, year = {2018}, author = {Davies, NG and Gardner, A}, title = {Monogamy promotes altruistic sterility in insect societies.}, journal = {Royal Society open science}, volume = {5}, number = {5}, pages = {172190}, pmid = {29892408}, issn = {2054-5703}, abstract = {Monogamy is associated with sibling-directed altruism in multiple animal taxa, including insects, birds and mammals. Inclusive-fitness theory readily explains this pattern by identifying high relatedness as a promoter of altruism. In keeping with this prediction, monogamy should promote the evolution of voluntary sterility in insect societies if sterile workers make for better helpers. However, a recent mathematical population-genetics analysis failed to identify a consistent effect of monogamy on voluntary worker sterility. Here, we revisit that analysis. First, we relax genetic assumptions, considering not only alleles of extreme effect-encoding either no sterility or complete sterility-but also alleles with intermediate effects on worker sterility. Second, we broaden the stability analysis-which focused on the invasibility of populations where either all workers are fully sterile or all workers are fully reproductive-to identify where intermediate pure or mixed evolutionarily stable states may occur. Third, we consider a broader range of demographically explicit ecological scenarios relevant to altruistic worker non-reproduction and to the evolution of eusociality more generally. We find that, in the absence of genetic constraints, monogamy always promotes altruistic worker sterility and may inhibit spiteful worker sterility. Our extended analysis demonstrates that an exact population-genetics approach strongly supports the prediction of inclusive-fitness theory that monogamy promotes sib-directed altruism in social insects.}, } @article {pmid29848655, year = {2018}, author = {Dos Santos, M and West, SA}, title = {The coevolution of cooperation and cognition in humans.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1879}, pages = {}, pmid = {29848655}, issn = {1471-2954}, mesh = {*Biological Evolution ; *Cognition ; *Cooperative Behavior ; Humans ; Models, Biological ; }, abstract = {Cooperative behaviours in archaic hunter-gatherers could have been maintained partly due to the gains from cooperation being shared with kin. However, the question arises as to how cooperation was maintained after early humans transitioned to larger groups of unrelated individuals. We hypothesize that after cooperation had evolved via benefits to kin, the consecutive evolution of cognition increased the returns from cooperating, to the point where benefits to self were sufficient for cooperation to remain stable when group size increased and relatedness decreased. We investigate the theoretical plausibility of this hypothesis, with both analytical modelling and simulations. We examine situations where cognition either (i) increases the benefits of cooperation, (ii) leads to synergistic benefits between cognitively enhanced cooperators, (iii) allows the exploitation of less intelligent partners, and (iv) the combination of these effects. We find that cooperation and cognition can coevolve-cooperation initially evolves, favouring enhanced cognition, which favours enhanced cooperation, and stabilizes cooperation against a drop in relatedness. These results suggest that enhanced cognition could have transformed the nature of cooperative dilemmas faced by early humans, thereby explaining the maintenance of cooperation between unrelated partners.}, } @article {pmid29802804, year = {2018}, author = {Wade, MJ and Fitzpatrick, CL and Lively, CM}, title = {50-year anniversary of Lloyd's "mean crowding": Ideas on patchy distributions.}, journal = {The Journal of animal ecology}, volume = {87}, number = {5}, pages = {1221-1226}, pmid = {29802804}, issn = {1365-2656}, support = {T32 HD049336/HD/NICHD NIH HHS/United States ; }, mesh = {Animals ; *Anniversaries and Special Events ; *Biological Evolution ; }, abstract = {This year marks the 50th anniversary of Monte B. Lloyd's "Mean Crowding" (1967) paper, in which he introduced a metric that accounts for an individual's experience of conspecific density. Mean crowding allows ecologists to measure the degree of spatial aggregation of individuals in a manner relevant to intraspecific competition for resources. We take the concept of mean crowding a step beyond its most common usage and that it has a mathematical relationship to many of the most important concepts in ecology and evolutionary biology. Mean crowding, a first-order approximation of the degree of nonrandomness in a distribution, can function as a powerful heuristic that can unify concepts across disciplines in a more general way that Lloyd originally envisioned.}, } @article {pmid29797146, year = {2018}, author = {Nila, S and Barthes, J and Crochet, PA and Suryobroto, B and Raymond, M}, title = {Kin Selection and Male Homosexual Preference in Indonesia.}, journal = {Archives of sexual behavior}, volume = {47}, number = {8}, pages = {2455-2465}, doi = {10.1007/s10508-018-1202-y}, pmid = {29797146}, issn = {1573-2800}, mesh = {Biological Evolution ; Family/*psychology ; Female ; Homosexuality, Male/*psychology ; Humans ; Indonesia ; Male ; *Reproduction ; *Selection, Genetic ; Sexual Behavior ; Sexual and Gender Minorities/psychology/*statistics & numerical data ; }, abstract = {Male homosexual preference (MHP) challenges evolutionary thinking because the preference for male-male relationships is heritable, implies a fertility cost (lower offspring number), and is relatively frequent in some societies (2-6% in Western countries) for a costly trait. It has been proposed that individuals with a MHP counterbalance reproductive costs through the transfer of resources to kin, thereby improving their indirect reproduction through kin's reproductive success. This kin selection hypothesis is not supported in Western countries and Japan, although consistent evidence has been obtained in Samoa. In this study, data from Java (Indonesia) were obtained to assess the avuncular tendencies of men with contrasting sexual orientation to measure possible resource transfer. Consistent with the kin selection hypothesis, males with a homosexual orientation reported an increased willingness to transfer resources toward nephews and nieces and declared having transferred more money to nephews and nieces. We developed a method to quantitatively estimate the contribution of kin selection on inclusive reproduction associated to sexual orientation, taking into account various possible biases. Kin selection reduced the direct reproductive cost of homosexual men by 20%, so suggesting that kin selection alone is insufficient to explain the maintenance of male homosexuality. Other potential factors are discussed, as well as the limitations of the study and the social determinant operating for the expression of increased avuncular tendencies of homosexual men.}, } @article {pmid29792446, year = {2019}, author = {Lang, SF and Fowers, BJ}, title = {An expanded theory of Alzheimer's caregiving.}, journal = {The American psychologist}, volume = {74}, number = {2}, pages = {194-206}, doi = {10.1037/amp0000323}, pmid = {29792446}, issn = {1935-990X}, mesh = {Alzheimer Disease/*nursing/*psychology ; Caregivers/*psychology ; Humans ; }, abstract = {The ancient and cross-culturally prevalent pattern of caregiving suggests that long-term caregiving is species characteristic for humans. If so, then an evolutionary account of the adaptation(s) that underwrite this caregiving is necessary, particularly for the one-sided and long-term nature of Alzheimer's caregiving. Four standard evolutionary explanations are evaluated: kin selection theory, the grandmother hypothesis, direct reciprocity, and indirect reciprocity. Each is found inadequate to explain caregiving because of the lack of reproductive benefits. These evolutionary accounts also assume that relationships are only valuable to the degree that they provide benefits and that relationship partners are predominantly motivated by self-interest. Attachment provides another explanation, which evolved initially to ensure infant protection and nurturance, but was exapted for important adult relationships. Attachment relationships naturally include caregiving and engender long-term relational commitment. Yet attachment theory is ambiguous about whether relationships are maintained for the sake of security benefits or because they have inherent value. This ambiguity undermines the explanatory value of attachment theory for Alzheimer's caregiving. Therefore, a shared identity theory is offered that highlights the inherent value of the relationship and the loved one, transcending the predominant focus on beneficial individual outcomes. The theory emphasizes the frequent human motivation to benefit others because of their mutual commitment, shared identity, and shared goals. The conclusion is that fully understanding and supporting the arduous efforts of caregiving for loved ones with Alzheimer's requires psychologists to fully appreciate and support the deep and meaningful motivations that often inspire the humanity seen in caregiving. (PsycINFO Database Record (c) 2019 APA, all rights reserved).}, } @article {pmid29765670, year = {2018}, author = {Koster, J}, title = {Family ties: the multilevel effects of households and kinship on the networks of individuals.}, journal = {Royal Society open science}, volume = {5}, number = {4}, pages = {172159}, pmid = {29765670}, issn = {2054-5703}, abstract = {Among social mammals, humans uniquely organize themselves into communities of households that are centred around enduring, predominantly monogamous unions of men and women. As a consequence of this social organization, individuals maintain social relationships both within and across households, and potentially there is conflict among household members about which social ties to prioritize or de-emphasize. Extending the logic of structural balance theory, I predict that there will be considerable overlap in the social networks of individual household members, resulting in a pattern of group-level reciprocity. To test this prediction, I advance the Group-Structured Social Relations Model, a generalized linear mixed model that tests for group-level effects in the inter-household social networks of individuals. The empirical data stem from social support interviews conducted in a community of indigenous Nicaraguan horticulturalists, and model results show high group-level reciprocity among households. Although support networks are organized around kinship, covariates that test predictions of kin selection models do not receive strong support, potentially because most kin-directed altruism occurs within households, not between households. In addition, the models show that households with high genetic relatedness in part from children born to adulterous relationships are less likely to assist each other.}, } @article {pmid29756687, year = {2018}, author = {Jänig, S and Weiß, BM and Widdig, A}, title = {Comparing the sniffing behavior of great apes.}, journal = {American journal of primatology}, volume = {80}, number = {6}, pages = {e22872}, doi = {10.1002/ajp.22872}, pmid = {29756687}, issn = {1098-2345}, mesh = {Age Factors ; Animals ; Behavior, Animal/physiology ; Female ; Food ; Gorilla gorilla/*physiology ; Male ; Pan paniscus/*physiology ; Pan troglodytes/*physiology ; Pongo abelii/*physiology ; Sex Factors ; Smell/*physiology ; Social Behavior ; }, abstract = {The importance of smell in humans is well established but we know little about it in regard to our closest relatives, the great apes, as systematic studies on their olfactory behavior are still lacking. Olfaction has long been considered to be of lesser importance in hominids given their relatively smaller olfactory bulbs, fewer functional olfactory receptor genes than other species and absence of a functional vomeronasal organ. Therefore, the aim of this study was to evaluate the use of olfaction in hominids. In particular, we observed sniffing behavior in captive groups of four species (Sumatran orangutans, Pongo abelii; Western lowland gorillas, Gorilla gorilla gorilla; Western chimpanzees, Pan troglodytes verus; bonobos, Pan paniscus) and evaluated in which contexts sniffing was used. Our results show that all investigated species frequently used the sense of smell, and that the sniffing frequency varied with species, sex, age, and context. Most sniffing events were observed in gorillas in comparison to the three other species. Sniffing frequencies were also influenced by sex, with males sniffing slightly more often than females. Furthermore, our results revealed an effect of age, with younger individuals sniffing more often than older individuals. All species mainly sniffed in the non-social context (i.e., toward food and other environmental items) rather than in the social context (i.e., at conspecifics), suggesting that the evaluation of the environment and the nutritional value of food items is of major importance to all great ape species investigated here. In contrast to the other species and female chimpanzees, however, male chimpanzees most often used olfaction to inspect their conspecifics. Together, our study suggests that olfaction is likely to be more important in great apes than previously appreciated.}, } @article {pmid29753459, year = {2018}, author = {Boose, K and White, F and Brand, C and Meinelt, A and Snodgrass, J}, title = {Infant handling in bonobos (Pan paniscus): Exploring functional hypotheses and the relationship to oxytocin.}, journal = {Physiology & behavior}, volume = {193}, number = {Pt A}, pages = {154-166}, doi = {10.1016/j.physbeh.2018.04.012}, pmid = {29753459}, issn = {1873-507X}, mesh = {Animals ; Behavior, Animal/*physiology ; Female ; Humans ; Learning/physiology ; Male ; Maternal Behavior/*physiology/psychology ; Models, Biological ; Oxytocin/*urine ; Pan paniscus/*metabolism/psychology ; Paternal Behavior/physiology/psychology ; *Social Behavior ; }, abstract = {Infant handling describes interactions between infants and non-maternal group members and is widespread across mammalian taxa. The expression of infant handling behaviors, defined as any affiliative or agonistic interaction between a group member and an infant, varies considerably among primate species. Several functional hypotheses may explain the adaptive value of infant handling including the Kin Selection hypothesis, which describes handling as a mechanism through which indirect fitness is increased and predicts a bias in handling behaviors directed toward related (genetic) infants; the Alliance Formation hypothesis, which describes handling as a social commodity and predicts females with infants will support handlers during conflict; and the Learning-to-Mother hypothesis, which describes handling as a mechanism through which handlers learn species-specific maternal behaviors and predicts that handling will occur most frequently in immature and nulliparous females. Using behavioral observation and data on urinary oxytocin, a neuropeptide hormone known to modulate maternal care and social bonds in mammals, the purpose of this study was to describe the pattern of infant handling in bonobos (Pan paniscus) and to explore proposed functional hypotheses. Data show that related infant-handler dyads occurred significantly more frequently than unrelated infant-handler dyads during some of the study period and that handling was positively correlated with support during conflict. Data also showed that immature and nulliparous females handled infants significantly more than other age-sex categories and exhibited higher post handling oxytocin values than other age-sex class. The trends identified in this data set provide insight into the role oxytocin may play in facilitating care-giving behaviors in young female bonobos and help to narrow the focus of future research efforts, particularly those associated with the Kin Selection, Alliance Formation, and Learning-to-Mother functional hypotheses.}, } @article {pmid29745213, year = {2017}, author = {Lai, BM and Wang, MZ and Shen, DS}, title = {[Bacterial quorum sensing: Cooperation and cheating].}, journal = {Ying yong sheng tai xue bao = The journal of applied ecology}, volume = {28}, number = {5}, pages = {1735-1742}, doi = {10.13287/j.1001-9332.201705.018}, pmid = {29745213}, issn = {1001-9332}, mesh = {*Bacteria ; Biofilms ; Ecological and Environmental Phenomena ; *Quorum Sensing ; }, abstract = {Quorum sensing (QS), a cell-to-cell communication, regulates a variety of social beha-viors, such as biofilm formation, public goods produce and gene horizontal transfer of bacteria. In the process of quorum sensing, public goods could be utilized by any members in the population, which was termed as cooperation. Notably, public goods also could be shared by the individuals who could not produce them, which was termed as cheating. Once cheaters come up, they possibly maintain equilibrium with cooperators, meanwhile they also possibly induce the collapse of population due to their rapid growth and shortage of public goods. Therefore, invasion of cheaters arouses wide attentions in medicine, agriculture, food science and so on regarded as a new strategy to control pathogens. In this study, based on the introduction about the theory of bacterial quorum sensing cooperation and cheating, we analyzed the factors influencing the formation and development of the relationship between cooperator and cheater. Moreover, we discussed the mechanism of stabilization in the relationship between cooperator and cheater, including kin selection, metabolic prudence, metabolic constraint (gene pleiotropy) and policing quorum sensing. Finally, some problems in current researches of quorum sensing cooperation and cheating were presented as well as the future research directions. We hoped this paper could deepen the understanding of bacterial quorum sen-sing and ecology of bacterial population.}, } @article {pmid29735672, year = {2018}, author = {Madgwick, PG and Stewart, B and Belcher, LJ and Thompson, CRL and Wolf, JB}, title = {Strategic investment explains patterns of cooperation and cheating in a microbe.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {21}, pages = {E4823-E4832}, pmid = {29735672}, issn = {1091-6490}, support = {//Wellcome Trust/United Kingdom ; BB/M01035X/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/M007146/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; WT095643AIA//Wellcome Trust/United Kingdom ; }, mesh = {*Biological Evolution ; *Cooperative Behavior ; Dictyostelium/*physiology ; *Game Theory ; Individuality ; *Models, Biological ; Spores, Protozoan/*physiology ; }, abstract = {Contributing to cooperation is typically costly, while its rewards are often available to all members of a social group. So why should individuals be willing to pay these costs, especially if they could cheat by exploiting the investments of others? Kin selection theory broadly predicts that individuals should invest more into cooperation if their relatedness to group members is high (assuming they can discriminate kin from nonkin). To better understand how relatedness affects cooperation, we derived the ‟Collective Investment" game, which provides quantitative predictions for patterns of strategic investment depending on the level of relatedness. We then tested these predictions by experimentally manipulating relatedness (genotype frequencies) in mixed cooperative aggregations of the social amoeba Dictyostelium discoideum, which builds a stalk to facilitate spore dispersal. Measurements of stalk investment by natural strains correspond to the predicted patterns of relatedness-dependent strategic investment, wherein investment by a strain increases with its relatedness to the group. Furthermore, if overall group relatedness is relatively low (i.e., no strain is at high frequency in a group) strains face a scenario akin to the "Prisoner's Dilemma" and suffer from insufficient collective investment. We find that strains employ relatedness-dependent segregation to avoid these pernicious conditions. These findings demonstrate that simple organisms like D. discoideum are not restricted to being ‟cheaters" or ‟cooperators" but instead measure their relatedness to their group and strategically modulate their investment into cooperation accordingly. Consequently, all individuals will sometimes appear to cooperate and sometimes cheat due to the dynamics of strategic investing.}, } @article {pmid29734799, year = {2018}, author = {Peters, K and Worrich, A and Weinhold, A and Alka, O and Balcke, G and Birkemeyer, C and Bruelheide, H and Calf, OW and Dietz, S and Dührkop, K and Gaquerel, E and Heinig, U and Kücklich, M and Macel, M and Müller, C and Poeschl, Y and Pohnert, G and Ristok, C and Rodríguez, VM and Ruttkies, C and Schuman, M and Schweiger, R and Shahaf, N and Steinbeck, C and Tortosa, M and Treutler, H and Ueberschaar, N and Velasco, P and Weiß, BM and Widdig, A and Neumann, S and Dam, NMV}, title = {Current Challenges in Plant Eco-Metabolomics.}, journal = {International journal of molecular sciences}, volume = {19}, number = {5}, pages = {}, pmid = {29734799}, issn = {1422-0067}, mesh = {*Ecology ; Metabolomics/*trends ; Plants/*genetics/metabolism ; }, abstract = {The relatively new research discipline of Eco-Metabolomics is the application of metabolomics techniques to ecology with the aim to characterise biochemical interactions of organisms across different spatial and temporal scales. Metabolomics is an untargeted biochemical approach to measure many thousands of metabolites in different species, including plants and animals. Changes in metabolite concentrations can provide mechanistic evidence for biochemical processes that are relevant at ecological scales. These include physiological, phenotypic and morphological responses of plants and communities to environmental changes and also interactions with other organisms. Traditionally, research in biochemistry and ecology comes from two different directions and is performed at distinct spatiotemporal scales. Biochemical studies most often focus on intrinsic processes in individuals at physiological and cellular scales. Generally, they take a bottom-up approach scaling up cellular processes from spatiotemporally fine to coarser scales. Ecological studies usually focus on extrinsic processes acting upon organisms at population and community scales and typically study top-down and bottom-up processes in combination. Eco-Metabolomics is a transdisciplinary research discipline that links biochemistry and ecology and connects the distinct spatiotemporal scales. In this review, we focus on approaches to study chemical and biochemical interactions of plants at various ecological levels, mainly plant[-]organismal interactions, and discuss related examples from other domains. We present recent developments and highlight advancements in Eco-Metabolomics over the last decade from various angles. We further address the five key challenges: (1) complex experimental designs and large variation of metabolite profiles; (2) feature extraction; (3) metabolite identification; (4) statistical analyses; and (5) bioinformatics software tools and workflows. The presented solutions to these challenges will advance connecting the distinct spatiotemporal scales and bridging biochemistry and ecology.}, } @article {pmid29728393, year = {2018}, author = {Bruger, EL and Waters, CM}, title = {Maximizing Growth Yield and Dispersal via Quorum Sensing Promotes Cooperation in Vibrio Bacteria.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {14}, pages = {}, pmid = {29728393}, issn = {1098-5336}, support = {R01 GM109259/GM/NIGMS NIH HHS/United States ; R01 GM110444/GM/NIGMS NIH HHS/United States ; R03 AI130554/AI/NIAID NIH HHS/United States ; }, mesh = {Culture Media/chemistry ; Evolution, Molecular ; Genotype ; *Models, Biological ; *Quorum Sensing ; Vibrio/*physiology ; }, abstract = {Quorum sensing (QS) is a form of bacterial chemical communication that regulates cellular phenotypes, including certain cooperative behaviors, in response to environmental and demographic changes. Despite the existence of proposed mechanisms that stabilize QS against defector exploitation, it is unclear if or how QS cooperators can proliferate in some model systems in populations mostly consisting of defectors. We predicted that growth in fragmented subpopulations could allow QS cooperators to invade a QS defector population. This could occur despite cooperators having lower relative fitnesses than defectors due to favored weighting of genotypes that produce larger populations of bacteria. Mixed metapopulations of Vibrio QS-proficient or unconditional cooperators and QS defectors were diluted and fragmented into isolated subpopulations in an environment that requires QS-regulated public good production to achieve larger population yields. Under these conditions, we observed global invasions of both cooperator genotypes into populations composed of primarily defectors. This spatially dependent increase in cooperator frequency was replicated for QS cooperators when mixed populations were competed in soft agar motility plates under conditions that allowed cooperators to disperse and outcompete defectors at the population edge, despite being less motile in isolation than defectors. These competition results show that the coordinated growth and dispersal of QS cooperators to additional resources is heavily favored in comparison to unconditional cooperation, and that dispersal of cooperators by motility into new environments, examined here in laboratory populations, constitutes a key mechanism for maintaining QS-regulated cooperation in the face of defection.IMPORTANCE Behaviors that are cooperative in nature are at risk of exploitation by cheating and are thus difficult to maintain by natural selection alone. While bacterial cell-cell communication, known as quorum sensing (QS), can stabilize microbial cooperative behaviors and is widespread in Vibrio species, it is unclear how QS can increase the frequency of cooperative strains in the presence of defectors without additional mechanisms. In this study, we demonstrate under multiple conditions that QS-mediated cooperation can increase in populations of Vibrio strains when cells experience narrow population bottlenecks or disperse from defectors. This occurred for both conditional cooperation mediated by QS and for unconditional cooperation, although conditional cooperators were better able to stabilize cooperation over a much wider range of conditions. Thus, we observed that population structuring allowed for assortment of competing genotypes and promoted cooperation via kin selection in microbes in a QS-dependent manner.}, } @article {pmid29717496, year = {2018}, author = {Cords, M and Minich, T and Roberts, SJ and Sleator, C}, title = {Evidence for paternal kin bias in the social affiliation of adult female blue monkeys.}, journal = {American journal of primatology}, volume = {80}, number = {5}, pages = {e22761}, doi = {10.1002/ajp.22761}, pmid = {29717496}, issn = {1098-2345}, mesh = {Animals ; *Behavior, Animal ; Cercopithecidae/*physiology ; Family ; Female ; Grooming ; Male ; *Social Behavior ; }, abstract = {If animals increase inclusive fitness by cooperating with relatives, nepotism should involve maternal and paternal kin equally, all else being equal. Evidence of a behavioral bias toward paternal half-siblings in primates is both limited and mixed, with most positive reports from papionins. To expand knowledge of paternal kin recognition, particularly in cercopithecine monkeys, we examined evidence for paternal kin bias in wild blue monkeys (Cercopithecus mitis), a species living mostly in one-male groups. Seasonal breeding and the amount of male reproductive skew in blue monkeys suggests that opportunities to distinguish paternal kin are plentiful, and their social system would make such discrimination beneficial. We compared spatial association and social contact (grooming and contact-sitting) of 20 adult females with at least one paternal half-sibling and at least one non-relative that were present at the same time. We used two data sets, one in which social partners were other parous females, the other in which they were juveniles. Data came from a 7-year period. When interacting with other adult females, subjects groomed and sat in contact with paternal half-siblings significantly more than with known non-kin, and there was a similar trend for spatial association. We detected no paternal kin bias in interactions with juvenile partners. Kin-biased affiliative contact with adult female partners did not appear to be based on age proximity, measured by birth cohort. The study species' social system suggests phenotype matching as the most likely alternative mechanism, though we could not test it directly. Across both behaviors, there was no significant relationship between the number of matrilineal kin a subject had and the degree to which she preferred paternal half-siblings over non-kin as affiliative partners. These findings contribute to a comparative understanding of paternal kin recognition in primates.}, } @article {pmid29679501, year = {2018}, author = {Rodrigues, AMM and Taylor, TB}, title = {Ecological and demographic correlates of cooperation from individual to budding dispersal.}, journal = {Journal of evolutionary biology}, volume = {31}, number = {7}, pages = {1058-1070}, doi = {10.1111/jeb.13286}, pmid = {29679501}, issn = {1420-9101}, mesh = {*Animal Distribution ; Animal Migration ; Animals ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; *Models, Biological ; Population Dynamics ; }, abstract = {Identifying the ecological and demographic factors that promote the evolution of cooperation is a major challenge for evolutionary biologists. Explanations for the adaptive evolution of cooperation seek to determine which factors make reproduction in cooperative groups more favourable than independent breeding or other selfish strategies. A vast majority of the hypotheses posit that cooperative groups emerge in the context of philopatry, high costs of dispersal, high population density and environmental stability. This route to cooperation, however, fails to explain a growing body of empirical evidence in which cooperation is not associated with one or more of these predictors. We propose an alternative evolutionary path towards the emergence of cooperation that accounts for the disparities observed in the current literature. We find that when dispersal is mediated by a group mode of dispersal, commonly termed budding dispersal, our mathematical model reveals an association between cooperation and immigration, lower costs of dispersal, low population density and environmental variability. Furthermore, by studying the continuum from the individual to the partial and full budding mode of dispersal, we can explicitly explain why the correlates of cooperation change under budding. This enables us to outline a general model for the evolution of cooperation that accounts for a substantial amount of empirical evidence. Our results suggest that natural selection may have favoured two major contrasting pathways for the evolution of cooperation depending on a set of key ecological and demographic factors.}, } @article {pmid29664006, year = {2018}, author = {Jiang, W and Wei, Y and Long, Y and Owen, A and Wang, B and Wu, X and Luo, S and Dang, Y and Ma, DK}, title = {A genetic program mediates cold-warming response and promotes stress-induced phenoptosis in C. elegans.}, journal = {eLife}, volume = {7}, number = {}, pages = {}, pmid = {29664006}, issn = {2050-084X}, support = {R01 AG032435/AG/NIA NIH HHS/United States ; R01 GM117461/GM/NIGMS NIH HHS/United States ; R00HL116654/HL/NHLBI NIH HHS/United States ; R00 HL116654/HL/NHLBI NIH HHS/United States ; R01GM117461/GM/NIGMS NIH HHS/United States ; R01AG032435/AG/NIA NIH HHS/United States ; }, mesh = {Animals ; Basic-Leucine Zipper Transcription Factors/*metabolism ; Caenorhabditis elegans/*physiology/*radiation effects ; Caenorhabditis elegans Proteins/*metabolism ; *Cold Temperature ; *Gene Expression Regulation ; Gene Regulatory Networks ; *Stress, Physiological ; }, abstract = {How multicellular organisms respond to and are impacted by severe hypothermic stress is largely unknown. From C. elegans screens for mutants abnormally responding to cold-warming stimuli, we identify a molecular genetic pathway comprising ISY-1, a conserved uncharacterized protein, and ZIP-10, a bZIP-type transcription factor. ISY-1 gatekeeps the ZIP-10 transcriptional program by regulating the microRNA mir-60. Downstream of ISY-1 and mir-60, zip-10 levels rapidly and specifically increase upon transient cold-warming exposure. Prolonged zip-10 up-regulation induces several protease-encoding genes and promotes stress-induced organismic death, or phenoptosis, of C. elegans. zip-10 deficiency confers enhanced resistance to prolonged cold-warming stress, more prominently in adults than larvae. We conclude that the ZIP-10 genetic program mediates cold-warming response and may have evolved to promote wild-population kin selection under resource-limiting and thermal stress conditions.}, } @article {pmid29657778, year = {2018}, author = {Mattison, SM and Seabright, E and Reynolds, AZ and Cao, JB and Brown, MJ and Feldman, MW}, title = {Adopted daughters and adopted daughters-in-law in Taiwan: a mortality analysis.}, journal = {Royal Society open science}, volume = {5}, number = {3}, pages = {171745}, pmid = {29657778}, issn = {2054-5703}, abstract = {Adoption is sometimes considered paradoxical from an evolutionary perspective because the costs spent supporting an adopted child would be better spent on rearing one's own. Kin selection theory is commonly used to solve this paradox, because the adoption of closely related kin contributes to the inclusive fitness of the adoptive parent. In this paper, we perform a novel test of kin selection theory in the context of adoption by asking whether adopted daughters-in-law, who contribute directly (i.e. genealogically) to the perpetuation of their adoptive families' lineages, experience lower mortality than daughters adopted for other purposes in historical Taiwan. We show that both classes of adopted daughter suffer lower mortality than biological daughters, but that the protective effect of adoption is stronger among daughters who were not adopted with the intention of perpetuating the family lineage. We speculate as to the possible benefits of such a pattern and emphasize the need to move beyond typological definitions of adoption to understand the specific costs and benefits involved in different forms of caring for others' children.}, } @article {pmid29624797, year = {2018}, author = {Yirmiya, K and Segal, NL and Bloch, G and Knafo-Noam, A}, title = {Prosocial and self-interested intra-twin pair behavior in monozygotic and dizygotic twins in the early to middle childhood transition.}, journal = {Developmental science}, volume = {21}, number = {6}, pages = {e12665}, doi = {10.1111/desc.12665}, pmid = {29624797}, issn = {1467-7687}, support = {//The Science of Generosity Initiative, funded by the Templeton Foundation/International ; 240994//European Research Council (ERC)/International ; }, mesh = {Child ; Child, Preschool ; Humans ; *Social Behavior ; Task Performance and Analysis ; Twins, Dizygotic/*psychology ; Twins, Monozygotic/*psychology ; Work Engagement ; }, abstract = {Several related and complementary theoretical frameworks have been proposed to explain the existence of prosocial behavior, despite its potential fitness cost to the individual. These include kin selection theory, proposing that organisms have a propensity to help those to whom they are genetically related, and reciprocity, referring to the benefit of being prosocial, depending on past and future mutual interactions. A useful paradigm to examine prosociality is to compare mean levels of this behavior between monozygotic (MZ) and dizygotic (DZ) twins. Here, we examined the performance of 883 6.5-year-old twins (139 MZ and 302 DZ same-sex 6.5-year-old full twin pairs) in the Differential Productivity Task. In this task, the twins' behaviors were observed under two conditions: working for themselves vs. working for their co-twin. There were no significant differences between the performances of MZ and DZ twins in the prosocial condition of the task. Correlations within the twin dyads were significantly higher in MZ than DZ twins in the self-interested condition. However, similar MZ and DZ correlations were found in the prosocial condition, supporting the role of reciprocity in twins' prosociality towards each other.}, } @article {pmid29622934, year = {2018}, author = {Bebbington, K and Fairfield, EA and Spurgin, LG and Kingma, SA and Dugdale, H and Komdeur, J and Richardson, DS}, title = {Joint care can outweigh costs of nonkin competition in communal breeders.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {29}, number = {1}, pages = {169-178}, pmid = {29622934}, issn = {1045-2249}, abstract = {Competition between offspring can greatly influence offspring fitness and parental investment decisions, especially in communal breeders where unrelated competitors have less incentive to concede resources. Given the potential for escalated conflict, it remains unclear what mechanisms facilitate the evolution of communal breeding among unrelated females. Resolving this question requires simultaneous consideration of offspring in noncommunal and communal nurseries, but such comparisons are missing. In the Seychelles warbler Acrocephalus sechellensis, we compare nestling pairs from communal nests (2 mothers) and noncommunal nests (1 mother) with singleton nestlings. Our results indicate that increased provisioning rate can act as a mechanism to mitigate the costs of offspring rivalry among nonkin. Increased provisioning in communal broods, as a consequence of having 2 female parents, mitigates any elevated costs of offspring rivalry among nonkin: per-capita provisioning and survival was equal in communal broods and singletons, but lower in noncommunal broods. Individual offspring costs were also more divergent in noncommunal broods, likely because resource limitation exacerbates differences in competitive ability between nestlings. It is typically assumed that offspring rivalry among nonkin will be more costly because offspring are not driven by kin selection to concede resources to their competitors. Our findings are correlational and require further corroboration, but may help explain the evolutionary maintenance of communal breeding by providing a mechanism by which communal breeders can avoid these costs.}, } @article {pmid29607032, year = {2018}, author = {Mukai, H and Hironaka, M and Tojo, S and Nomakuchi, S}, title = {Maternal hatching synchronization in a subsocial burrower bug mitigates the risk of future sibling cannibalism.}, journal = {Ecology and evolution}, volume = {8}, number = {6}, pages = {3376-3381}, pmid = {29607032}, issn = {2045-7758}, abstract = {Sibling cannibalism-the killing and consumption of conspecifics within broods-carries a high risk of direct and inclusive fitness loss for parents and offspring. We reported previously that a unique vibrational behavior shown by the mother of the subsocial burrower bug, Adomerus rotundus (Heteroptera: Cydnidae), induced synchronous hatching. Maternal regulation may be one of the most effective mechanisms for preventing or limiting sibling cannibalism. Here, we tested the hypothesis that synchronous hatching induced by maternal vibration in A. rotundus prevents sibling cannibalism. Mothers and their mature egg masses were allocated to three groups: synchronous hatching by maternal vibration (SHmv), synchronous hatching by artificial vibration (SHav), and asynchronous hatching (AH). We then investigated the influence of each hatching strategy on the occurrence of sibling cannibalism of eggs and early-instar nymphs in the laboratory. No difference in the proportion of eggs cannibalized was observed among the three groups. However, the proportion of nymphs cannibalized was higher in the AH group than in the SHmv group. The difference in the number of days to first molting within clutch was significantly higher in the AH group than in the SHmv group. Junior nymphs were sometimes eaten by senior nymphs. However, immediately after molting, senior nymphs were at a high risk of being eaten by junior nymphs. Our results indicate that synchronous hatching of A. rotundus is necessary to mitigate the risk of sibling cannibalism.}, } @article {pmid29607027, year = {2018}, author = {Best, R and Ruxton, GD and Gardner, A}, title = {Intragroup and intragenomic conflict over chemical defense against predators.}, journal = {Ecology and evolution}, volume = {8}, number = {6}, pages = {3322-3329}, pmid = {29607027}, issn = {2045-7758}, abstract = {Insects are often chemically defended against predators. There is considerable evidence for a group-beneficial element to their defenses, and an associated potential for individuals to curtail their own investment in costly defense while benefitting from the investments of others, termed "automimicry." Although females in chemically defended taxa often lay their eggs in clusters, leading to siblings living in close proximity, current models of automimicry have neglected kin-selection effects, which may be expected to curb the evolution of such selfishness. Here, we develop a general theory of automimicry that explicitly incorporates kin selection. We investigate how female promiscuity modulates intragroup and intragenomic conflicts overinvestment into chemical defense, finding that individuals are favored to invest less than is optimal for their group, and that maternal-origin genes favor greater investment than do paternal-origin genes. We translate these conflicts into readily testable predictions concerning gene expression patterns and the phenotypic consequences of genomic perturbations, and discuss how our results may inform gene discovery in relation to economically important agricultural products.}, } @article {pmid29606788, year = {2018}, author = {Weiß, BM and Kücklich, M and Thomsen, R and Henkel, S and Jänig, S and Kulik, L and Birkemeyer, C and Widdig, A}, title = {Chemical composition of axillary odorants reflects social and individual attributes in rhesus macaques.}, journal = {Behavioral ecology and sociobiology}, volume = {72}, number = {4}, pages = {65}, pmid = {29606788}, issn = {0340-5443}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {ABSTRACT: Scents play an important role in the life of most terrestrial mammals and may transmit valuable information about conspecifics. Olfaction was long considered of low importance in Old World monkeys due to their relative reduction of olfactory structures and low incidence of scent-marking behavior but has been increasingly recognized for mediating social relationships in recent years. Yet, studies investigating the composition of their chemical cues remain scarce. In the present study, we analyzed the potential information content of chemicals present on the skin of rhesus macaques (Macaca mulatta). We collected axillary secretions from 60 animals of the semifree-ranging population on Cayo Santiago (Puerto Rico, USA) with precleaned cotton swabs from which the secretions were subsequently extracted and analyzed by gas chromatography-mass spectrometry. Rhesus macaque axillary odorants varied in their overall similarity and composition. This variation was attributable to differences in sex, group membership, and kinship and further appeared to reflect age and rank in parts of our sample. The compounds most strongly associated with this variation primarily comprised larger molecular weight aldehydes and steroids. Such compounds are considered to be perceivable by the primate olfactory system through close-range interactions or through breakdown into smaller molecules by bacterial fermentation. Overall, our results provide additional evidence that odors of Old World monkeys reflect a wealth of potential information about their carrier, which provides the basis for chemical communication via body odors; however, its use by conspecifics needs to be confirmed in bioassays.

SIGNIFICANCE STATEMENT: One prerequisite for olfactory communication is the presence of systematic variation in animal odors that is related to attributes such as age, sex, or kinship. The composition of odors has been examined in numerous mammals but, with the exception of humans, remains poorly understood in Old World monkeys and apes, taxonomic groups in which most species do not show scent-marking behavior. In the present study, we show that the composition of axillary secretions of an Old World monkey, the rhesus macaque, reflects sex, group membership, relatedness, and possibly also age and rank. This variation thus provides a basis for olfactory communication in Old World monkeys.}, } @article {pmid29593107, year = {2018}, author = {Shimoji, H and Kikuchi, T and Ohnishi, H and Kikuta, N and Tsuji, K}, title = {Social enforcement depending on the stage of colony growth in an ant.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1875}, pages = {}, pmid = {29593107}, issn = {1471-2954}, mesh = {*Altruism ; Animals ; Ants/genetics/*physiology ; Behavior, Animal/*physiology ; Biological Evolution ; DNA/genetics ; Female ; Genetic Variation/genetics ; Genotype ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; Reproduction/genetics/physiology ; Selection, Genetic ; }, abstract = {Altruism is a paradox in Darwinian evolution. Policing is an important mechanism of the evolution and maintenance of altruism. A recently developed dynamic game model incorporating colony demography and inclusive fitness predicts that, in hymenopteran social insects, policing behaviour enforcing reproductive altruism in group members depends strongly on the colony growth stage, with strong policing as the colony develops and a relaxation of policing during the reproductive phase. Here, we report clear evidence supporting this prediction. In the ant Diacamma sp., reproduction by workers was suppressed by worker policing when the colony was small, whereas in large, mature colonies worker policing was relaxed and worker-produced males emerged. Conditional expression of traits can provide strong empirical evidence for natural selection theory if the expression pattern is precisely predicted by the theory, and our results illustrate the importance of intracolony population dynamics in the evolution of social systems.}, } @article {pmid29593076, year = {2018}, author = {Brügger, RK and Kappeler-Schmalzriedt, T and Burkart, JM}, title = {Reverse audience effects on helping in cooperatively breeding marmoset monkeys.}, journal = {Biology letters}, volume = {14}, number = {3}, pages = {}, pmid = {29593076}, issn = {1744-957X}, mesh = {Animals ; Callithrix/*physiology/psychology ; *Cooperative Behavior ; *Helping Behavior ; *Reproduction ; }, abstract = {Cooperatively breeding common marmosets show substantial variation in the amount of help they provide. Pay-to-stay and social prestige models of helping attribute this variation to audience effects, i.e. that individuals help more if group members can witness their interactions with immatures, whereas models of kin selection, group augmentation or those stressing the need to gain parenting experience do not predict any audience effects. We quantified the readiness of adult marmosets to share food in the presence or absence of other group members. Contrary to both predictions, we found a reverse audience effect on food-sharing behaviour: marmosets would systematically share more food with immatures when no audience was present. Thus, helping in common marmosets, at least in related family groups, does not support the pay-to-stay or the social prestige model, and helpers do not take advantage of the opportunity to engage in reputation management. Rather, the results appear to reflect a genuine concern for the immatures' well-being, which seems particularly strong when solely responsible for the immatures.}, } @article {pmid29559642, year = {2018}, author = {Towers, JR and Hallé, MJ and Symonds, HK and Sutton, GJ and Morton, AB and Spong, P and Borrowman, JP and Ford, JKB}, title = {Infanticide in a mammal-eating killer whale population.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {4366}, pmid = {29559642}, issn = {2045-2322}, mesh = {Animals ; *Animals, Newborn ; *Behavior, Animal ; Bottle-Nosed Dolphin/psychology ; Drowning/*etiology ; Feeding Behavior/psychology ; Female ; Male ; Mothers/psychology ; Sexual Behavior, Animal ; Skin/injuries ; *Social Behavior ; Video Recording ; Vocalization, Animal ; Whale, Killer/*psychology ; Whales/psychology ; Wounds, Penetrating ; }, abstract = {Infanticide can be an extreme result of sexual conflict that drives selection in species in which it occurs. It is a rarely observed behaviour but some evidence for its occurrence in cetaceans exists in three species of dolphin. Here we describe observations of an adult male killer whale (Orcinus orca) and his post-reproductive mother killing a neonate belonging to an unrelated female from the same population in the North Pacific. This is the first account of infanticide reported in killer whales and the only case committed jointly by an adult male and his mother outside of humans. Consistent with findings in other social mammals, we suggest that infanticide is a sexually selected behaviour in killer whales that could provide subsequent mating opportunities for the infanticidal male and thereby provide inclusive fitness benefits for his mother.}, } @article {pmid29558609, year = {2017}, author = {Schultner, E and Oettler, J and Helanterä, H}, title = {The Role of Brood in Eusocial Hymenoptera.}, journal = {The Quarterly review of biology}, volume = {92}, number = {1}, pages = {39-78}, doi = {10.1086/690840}, pmid = {29558609}, issn = {0033-5770}, mesh = {Animals ; *Behavior, Animal ; Female ; Hymenoptera/*physiology ; Male ; Population Dynamics ; *Social Behavior ; }, abstract = {Study of social traits in offspring traditionally reflects on interactions in simple family groups, with famous examples including parent-offspring conflict and sibling rivalry in birds and mammals. In contrast, studies of complex social groups such as the societies of ants, bees, and wasps focus mainly on adults and, in particular, on traits and interests of queens and workers. The social role of developing individuals in complex societies remains poorly understood. We attempt to fill this gap by illustrating that development in social Hymenoptera constitutes a crucial life stage with important consequences for the individual as well as the colony. We begin by describing the complex social regulatory network that modulates development in Hymenoptera societies. By highlighting the inclusive fitness interests of developing individuals, we show that they may differ from those of other colony members. We then demonstrate that offspring have evolved specialized traits that allow them to play a functional, cooperative role within colonies and give them the potential power to act toward increasing their inclusive fitness. We conclude by providing testable predictions for investigating the role of brood in colony interactions and giving a general outlook on what can be learned from studying offspring traits in hymenopteran societies.}, } @article {pmid29543401, year = {2018}, author = {Leedale, AE and Sharp, SP and Simeoni, M and Robinson, EJH and Hatchwell, BJ}, title = {Fine-scale genetic structure and helping decisions in a cooperatively breeding bird.}, journal = {Molecular ecology}, volume = {27}, number = {7}, pages = {1714-1726}, doi = {10.1111/mec.14553}, pmid = {29543401}, issn = {1365-294X}, mesh = {Animals ; *Breeding ; Female ; Male ; Nesting Behavior ; Passeriformes/*genetics ; Phylogeny ; }, abstract = {In animal societies, characteristic demographic and dispersal patterns may lead to genetic structuring of populations, generating the potential for kin selection to operate. However, even in genetically structured populations, social interactions may still require kin discrimination for cooperative behaviour to be directed towards relatives. Here, we use molecular genetics and long-term field data to investigate genetic structure in an adult population of long-tailed tits Aegithalos caudatus, a cooperative breeder in which helping occurs within extended kin networks, and relate this to patterns of helping with respect to kinship. Spatial autocorrelation analyses reveal fine-scale genetic structure within our population, such that related adults of either sex are spatially clustered following natal dispersal, with relatedness among nearby males higher than that among nearby females, as predicted by observations of male-biased philopatry. This kin structure creates opportunities for failed breeders to gain indirect fitness benefits via redirected helping, but crucially, most close neighbours of failed breeders are unrelated and help is directed towards relatives more often than expected by indiscriminate helping. These findings are consistent with the effective kin discrimination mechanism known to exist in long-tailed tits and support models identifying kin selection as the driver of cooperation.}, } @article {pmid29525917, year = {2018}, author = {Haemmerli, S and Thill, C and Amici, F and Cacchione, T}, title = {Domestic horses (Equus ferus caballus) fail to intuitively reason about object properties like solidity and weight.}, journal = {Animal cognition}, volume = {21}, number = {3}, pages = {441-446}, doi = {10.1007/s10071-018-1177-z}, pmid = {29525917}, issn = {1435-9456}, mesh = {Animals ; *Cognition ; Female ; Form Perception ; Horses/*psychology ; Learning ; Male ; Reward ; *Visual Perception ; }, abstract = {From early infancy, humans reason about the external world in terms of identifiable, solid, cohesive objects persisting in space and time. This is one of the most fundamental human skills, which may be part of our innate conception of object properties. Although object permanence has been extensively studied across a variety of taxa, little is known about how non-human animals reason about other object properties. In this study, we therefore tested how domestic horses (Equus ferus caballus) intuitively reason about object properties like solidity and height, to locate hidden food. Horses were allowed to look for a food reward behind two opaque screens, only one of which had either the proper height or inclination to hide food rewards. Our results suggest that horses could not intuitively reason about physical object properties, but rather learned to select the screen with the proper height or inclination from the second set of 5 trials.}, } @article {pmid29515868, year = {2018}, author = {Thomas, MG and Ji, T and Wu, J and He, Q and Tao, Y and Mace, R}, title = {Kinship underlies costly cooperation in Mosuo villages.}, journal = {Royal Society open science}, volume = {5}, number = {2}, pages = {171535}, pmid = {29515868}, issn = {2054-5703}, abstract = {The relative importance of social evolution theories such as kin selection, direct reciprocity and need-based transfers in explaining real-world cooperation is the source of much debate. Previous field studies of cooperation in human communities have revealed variability in the extent to which each of these theories explains human sociality in different contexts. We conducted multivariate social network analyses predicting costly cooperation-labouring on another household's farm-in 128 082 dyads of Mosuo farming households in southwest China. Through information-theoretic model selection, we tested the roles played by genealogical relatedness, affinal relationships (including reproductive partners), reciprocity, relative need, wealth, household size, spatial proximity and gift-giving in an economic game. The best-fitting model included all factors, along with interactions between relatedness and (i) reciprocity, (ii) need, (iii) the presence of own children in another household and (iv) proximity. Our results show how a real-world form of cooperation was driven by kinship. Households tended to help kin in need (but not needy non-kin) and travel further to help spatially distant relatives. Households were more likely to establish reciprocal relationships with distant relatives and non-kin but closer kin cooperated regardless of reciprocity. These patterns of kin-driven cooperation show the importance of inclusive fitness in understanding human social behaviour.}, } @article {pmid29515836, year = {2018}, author = {Lehtonen, J and Schwanz, LE}, title = {Mate limitation and sex ratio evolution.}, journal = {Royal Society open science}, volume = {5}, number = {2}, pages = {171135}, pmid = {29515836}, issn = {2054-5703}, abstract = {Sex ratio evolution has been one of the most successful areas of evolutionary theory. Pioneered by Düsing and Fisher under panmixia, and later extended by Hamilton to cover local mate competition (LMC), these models often assume, either implicitly or explicitly, that all females are fertilized. Here, we examine the effects of relaxing this assumption, under both panmictic and LMC models with diploid genetics. We revisit the question of the mathematical relationship between sex ratio and probability of fertilization, and use these results to model sex ratio evolution under risk of incomplete fertilization. We find that (i) under panmixia, mate limitation has no effect on the evolutionarily stable strategy (ESS) sex allocation; (ii) under LMC, mate limitation can make sex allocation less female-biased than under complete fertilization; (iii) contrary to what is occasionally stated, a significant fraction of daughters can remain unfertilized at the ESS in LMC with mate limitation; (iv) with a commonly used mating function, the fraction of unfertilized daughters can be quite large, and (v) with more realistic fertilization functions, the deviation becomes smaller. The models are presented in three equivalent forms: individual selection, kin selection and group selection. This serves as an example of the equivalence of the methods, while each approach has their own advantages. We discuss possible extensions of the model to haplodiploidy.}, } @article {pmid29514963, year = {2018}, author = {Schweinfurth, MK and Taborsky, M}, title = {Relatedness decreases and reciprocity increases cooperation in Norway rats.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1874}, pages = {}, pmid = {29514963}, issn = {1471-2954}, mesh = {Animals ; *Cooperative Behavior ; *Decision Making ; Male ; Rats/*genetics/*psychology ; *Social Behavior ; }, abstract = {Kin selection and reciprocity are two mechanisms underlying the evolution of cooperation, but the relative importance of kinship and reciprocity for decisions to cooperate are yet unclear for most cases of cooperation. Here, we experimentally tested the relative importance of relatedness and received cooperation for decisions to help a conspecific in wild-type Norway rats (Rattus norvegicus). Test rats provided more food to non-kin than to siblings, and they generally donated more food to previously helpful social partners than to those that had refused help. The rats thus applied reciprocal cooperation rules irrespective of relatedness, highlighting the importance of reciprocal help for cooperative interactions among both related and unrelated conspecifics.}, } @article {pmid29513655, year = {2018}, author = {Kennedy, P and Higginson, AD and Radford, AN and Sumner, S}, title = {Altruism in a volatile world.}, journal = {Nature}, volume = {555}, number = {7696}, pages = {359-362}, pmid = {29513655}, issn = {1476-4687}, support = {682253/ERC_/European Research Council/International ; }, mesh = {*Altruism ; Animals ; *Biological Evolution ; Genetic Fitness ; Genotype ; Models, Biological ; Reproduction/genetics/physiology ; Selection, Genetic ; Stochastic Processes ; }, abstract = {The evolution of altruism-costly self-sacrifice in the service of others-has puzzled biologists since The Origin of Species. For half a century, attempts to understand altruism have developed around the concept that altruists may help relatives to have extra offspring in order to spread shared genes. This theory-known as inclusive fitness-is founded on a simple inequality termed Hamilton's rule. However, explanations of altruism have typically not considered the stochasticity of natural environments, which will not necessarily favour genotypes that produce the greatest average reproductive success. Moreover, empirical data across many taxa reveal associations between altruism and environmental stochasticity, a pattern not predicted by standard interpretations of Hamilton's rule. Here we derive Hamilton's rule with explicit stochasticity, leading to new predictions about the evolution of altruism. We show that altruists can increase the long-term success of their genotype by reducing the temporal variability in the number of offspring produced by their relatives. Consequently, costly altruism can evolve even if it has a net negative effect on the average reproductive success of related recipients. The selective pressure on volatility-suppressing altruism is proportional to the coefficient of variation in population fitness, and is therefore diminished by its own success. Our results formalize the hitherto elusive link between bet-hedging and altruism, and reveal missing fitness effects in the evolution of animal societies.}, } @article {pmid29507206, year = {2018}, author = {Noh, S and Geist, KS and Tian, X and Strassmann, JE and Queller, DC}, title = {Genetic signatures of microbial altruism and cheating in social amoebas in the wild.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {12}, pages = {3096-3101}, pmid = {29507206}, issn = {1091-6490}, mesh = {Adaptation, Physiological ; Dictyostelium/*genetics/*physiology ; Evolution, Molecular ; Gene Expression Regulation ; Genetic Variation ; Genome, Protozoan ; Selection, Genetic ; }, abstract = {Many microbes engage in social interactions. Some of these have come to play an important role in the study of cooperation and conflict, largely because, unlike most animals, they can be genetically manipulated and experimentally evolved. However, whereas animal social behavior can be observed and assessed in natural environments, microbes usually cannot, so we know little about microbial social adaptations in nature. This has led to some difficult-to-resolve controversies about social adaptation even for well-studied traits such as bacterial quorum sensing, siderophore production, and biofilms. Here we use molecular signatures of population genetics and molecular evolution to address controversies over the existence of altruism and cheating in social amoebas. First, we find signatures of rapid adaptive molecular evolution that are consistent with social conflict being a significant force in nature. Second, we find population-genetic signatures of purifying selection to support the hypothesis that the cells that form the sterile stalk evolve primarily through altruistic kin selection rather than through selfish direct reproduction. Our results show how molecular signatures can provide insight into social adaptations that cannot be observed in their natural context, and they support the hypotheses that social amoebas in the wild are both altruists and cheaters.}, } @article {pmid29494630, year = {2018}, author = {Garay, J and Csiszár, V and Móri, TF and Szilágyi, A and Varga, Z and Számadó, S}, title = {Juvenile honest food solicitation and parental investment as a life history strategy: A kin demographic selection model.}, journal = {PloS one}, volume = {13}, number = {3}, pages = {e0193420}, pmid = {29494630}, issn = {1932-6203}, mesh = {Animals ; Feeding Behavior ; *Life History Traits ; Markov Chains ; *Models, Theoretical ; Phenotype ; Seasons ; }, abstract = {Parent-offspring communication remains an unresolved challenge for biologist. The difficulty of the challenge comes from the fact that it is a multifaceted problem with connections to life-history evolution, parent-offspring conflict, kin selection and signalling. Previous efforts mainly focused on modelling resource allocation at the expense of the dynamic interaction during a reproductive season. Here we present a two-stage model of begging where the first stage models the interaction between nestlings and parents within a nest and the second stage models the life-history trade-offs. We show in an asexual population that honest begging results in decreased variance of collected food between siblings, which leads to mean number of surviving offspring. Thus, honest begging can be seen as a special bet-hedging against informational uncertainty, which not just decreases the variance of fitness but also increases the arithmetic mean.}, } @article {pmid29492037, year = {2018}, author = {Wright, CM and Hyland, TD and Izzo, AS and McDermott, DR and Tibbetts, EA and Pruitt, JN}, title = {Polistes metricus queens exhibit personality variation and behavioral syndromes.}, journal = {Current zoology}, volume = {64}, number = {1}, pages = {45-52}, pmid = {29492037}, issn = {1674-5507}, abstract = {Consistent differences in behavior between individuals, otherwise known as animal personalities, have become a staple in behavioral ecology due to their ability to explain a wide range of phenomena. Social organisms are especially serviceable to animal personality techniques because they can be used to explore behavioral variation at both the individual and group level. Despite the success of personality research in social organisms generally, and social Hymenoptera in particular, social wasps (Vespidae) have received little to no attention in the personality literature. In the present study, we test Polistes metricus (Vespidae; Polistinae) paper wasp queens for the presence of repeatable variation in, and correlations ("behavioral syndromes") between, several commonly used personality metrics: boldness, aggressiveness, exploration, and activity. Our results indicate that P. metricus queens exhibit personalities for all measured traits and correlations between different behavioral measures. Given that paper wasps have served as a model organism for a wide range of phenomena such as kin selection, dominance hierarchies, mate choice, facial recognition, social parasitism, and chemical recognition, we hope that our results will motivate researchers to explore whether, or to what degree, queen personality is important in their research programs.}, } @article {pmid29491991, year = {2017}, author = {Dale, R and Marshall-Pescini, S and Range, F}, title = {Do females use their sexual status to gain resource access? Investigating food-for-sex in wolves and dogs.}, journal = {Current zoology}, volume = {63}, number = {3}, pages = {323-330}, pmid = {29491991}, issn = {1674-5507}, support = {311870/ERC_/European Research Council/International ; }, abstract = {While food sharing among related individuals can be explained by kin selection, food sharing between unrelated individuals has been more of an evolutionary puzzle. The food-for-sex hypothesis provides an explanation for the occurrence of food sharing among nonkin. However, little is known about the socio-ecological factors that can promote such a commodity exchange. A species mating system is a factor potentially influencing food-for-sex patterns of behavior. Here, we compared wolves, which form pair-bonds, with dogs, which are typically promiscuous in free-ranging contexts, to investigate the effect of reproductive stages on the behavior around a food source in 2 different contexts. Furthermore, we considered the roles of both the males and the females in the potential food-for-sex exchange. Results indicate that in both species and for both sexes the breeding period promotes decreased aggression. Additionally, females were more persistent in their attempts to access the food and were able to monopolize the resource more when in heat as compared to outside the breeding period. Finally, in dogs, but not wolves, females spent more time in proximity to the male's bone and had a shorter latency to start eating it when in heat. Overall, this study demonstrates that the food-for-sex hypothesis plays a part in intersexual food sharing in canids, and highlights the role of females in the interaction. These effects were especially the case in dogs, suggesting a potential effect of mating system on food-for-sex responses.}, } @article {pmid29449670, year = {2018}, author = {Amici, F and Call, J and Watzek, J and Brosnan, S and Aureli, F}, title = {Social inhibition and behavioural flexibility when the context changes: a comparison across six primate species.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {3067}, pmid = {29449670}, issn = {2045-2322}, mesh = {Animals ; Atelinae/psychology ; Behavior, Animal/*physiology ; Cebus/psychology ; Food ; Gorilla gorilla/psychology ; Hominidae/*psychology ; *Learning ; Pan paniscus/psychology ; Pan troglodytes/psychology ; Pongo/psychology ; }, abstract = {The ability to inhibit previously employed strategies and flexibly adjust behavioural responses to external conditions may be critical for individual survival. However, it is unclear which factors predict their distribution across species. Here, we investigated social inhibition and behavioural flexibility in six primate species (chimpanzees, bonobos, orangutans, gorillas, capuchin monkeys and spider monkeys) differing in terms of phylogenetic relatedness, foraging ecology and social organization. Depending on the social context, individuals could maximize their food intake by inhibiting the selection of a larger food reward in one condition (i.e. inhibition), but not in others, which required them to flexibly switching strategies across conditions (i.e. behavioural flexibility). Overall, our study revealed inter-specific differences in social inhibition and behavioural flexibility, which partially reflected differences in fission-fusion dynamics. In particular, orangutans and chimpanzees showed the highest level of inhibitory skills, while gorillas and capuchin monkeys showed the lowest one. In terms of behavioural flexibility, orangutans and spider monkeys were the best performers, while bonobos and capuchin monkeys were the worst ones. These results contribute to our understanding that inhibition and behavioural flexibility may be linked in more complex ways than usually thought, although both abilities play a crucial role in efficient problem solving.}, } @article {pmid29438052, year = {2018}, author = {Brahma, A and Mandal, S and Gadagkar, R}, title = {Current indirect fitness and future direct fitness are not incompatible.}, journal = {Biology letters}, volume = {14}, number = {2}, pages = {}, pmid = {29438052}, issn = {1744-957X}, mesh = {Animals ; Behavior, Animal/*physiology ; Feeding Behavior ; Female ; Genetic Fitness/*physiology ; Social Behavior ; Wasps/*physiology ; }, abstract = {In primitively eusocial insects, many individuals function as workers despite being capable of independent reproduction. Such altruistic behaviour is usually explained by the argument that workers gain indirect fitness by helping close genetic relatives. The focus on indirect fitness has left open the question of whether workers are also capable of getting direct fitness in the future in spite of working towards indirect fitness in the present. To investigate this question, we recorded behavioural profiles of all wasps on six naturally occurring nests of Ropalidia marginata, and then isolated all wasps in individual plastic boxes, giving them an opportunity to initiate nests and lay eggs. We found that 41% of the wasps successfully did so. Compared to those that failed to initiate nests, those that did were significantly younger, had significantly higher frequency of self-feeding behaviour on their parent nests but were not different in the levels of work performed in the parent nests. Thus ageing and poor feeding, rather than working for their colonies, constrain individuals for future independent reproduction. Hence, future direct fitness and present work towards gaining indirect fitness are not incompatible, making it easier for worker behaviour to be selected by kin selection or multilevel selection.}, } @article {pmid29337077, year = {2018}, author = {Pande, S and Velicer, GJ}, title = {Chimeric Synergy in Natural Social Groups of a Cooperative Microbe.}, journal = {Current biology : CB}, volume = {28}, number = {2}, pages = {262-267.e3}, doi = {10.1016/j.cub.2017.11.043}, pmid = {29337077}, issn = {1879-0445}, mesh = {*Chimera ; *Microbial Interactions ; Myxococcus xanthus/*physiology ; Spores, Bacterial/physiology ; }, abstract = {Many cooperative species form internally diverse social groups in which individual fitness depends significantly on group-level productivity from cooperation [1-4]. For such species, selection is expected to often disfavor within-group diversity that reduces cooperative productivity [5, 6]. While diversity within social groups is known to enhance productivity in some animals [7-9], diversity within natural groups of social microbes is largely unexamined in this regard. Cells of the soil bacterium Myxococcus xanthus respond to starvation by constructing multicellular fruiting bodies within each of which a subpopulation of cells transforms into stress-resistant spores [10]. Fruiting bodies isolated from soil often harbor substantial endemic diversity [11] that is, nonetheless, lower than between-group diversity, which increases with distance from millimeter to global scales [12-14]. We show that M. xanthus clones isolated from the same fruiting body often collectively produce more viable spores in chimeric groups than expected from sporulation in genetically homogeneous groups. In contrast, chimerism among clones derived from different fruiting bodies tends to reduce group productivity, and it does so increasingly as a function of spatial distance between fruiting-body sample sites. For one fruiting body examined in detail, chimeric synergy-a positive quantitative effect of chimerism on group productivity-is distributed broadly across an interaction network rather than limited to a few interactions. We propose that these results strengthen the plausibility of the hypothesis that selection may operate not only within Myxococcus groups, but also between kin groups to disfavor within-group variation that reduces productivity while allowing some forms of diversity that generate chimeric synergy to persist.}, } @article {pmid29295937, year = {2018}, author = {Wang, C and Lu, X}, title = {Hamilton's inclusive fitness maintains heritable altruism polymorphism through rb = c.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {115}, number = {8}, pages = {1860-1864}, pmid = {29295937}, issn = {1091-6490}, mesh = {*Altruism ; Animals ; Behavior, Animal ; Birds/*genetics ; Female ; *Genetic Fitness ; Genotype ; Male ; *Models, Genetic ; *Polymorphism, Genetic ; Social Behavior ; }, abstract = {How can altruism evolve or be maintained in a selfish world? Hamilton's rule shows that the former process will occur when rb > c-the benefits to the recipients of an altruistic act b, weighted by the relatedness between the social partners r, exceed the costs to the altruists c-drives altruistic genotypes spreading against nonaltruistic ones. From this rule, we infer that altruistic genotypes will persist in a population by forming a stable heritable polymorphism with nonaltruistic genotypes if rb = c makes inclusive fitness of the two morphs equal. We test this prediction using the data of 12 years of study on a cooperatively breeding bird, the Tibetan ground tit Pseudopodoces humilis, where helping is performed by males only and kin-directed. Individual variation in ever acting as a helper was heritable (h[2] = 0.47), and the resultant altruism polymorphism remained stable as indicated by low-level annual fluctuation of the percentage of helpers among all adult males (24-28%). Helpers' indirect fitness gains from increased lifetime reproductive success of related breeders statistically fully compensated for their lifetime direct fitness losses, suggesting that rb = c holds. While our work provides a fundamental support for Hamilton's idea, it highlights the equivalent inclusive fitness returns to altruists and nonaltruists mediated by rb = c as a theoretically and realistically important mechanism to maintain social polymorphism.}, } @article {pmid29289605, year = {2018}, author = {Yamauchi, A and van Baalen, M and Sabelis, MW}, title = {Spatial patterns generated by simultaneous cooperation and exploitation favour the evolution of altruism.}, journal = {Journal of theoretical biology}, volume = {441}, number = {}, pages = {58-67}, doi = {10.1016/j.jtbi.2017.12.027}, pmid = {29289605}, issn = {1095-8541}, mesh = {*Algorithms ; *Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; Humans ; *Models, Theoretical ; *Social Behavior ; }, abstract = {In kin selection theory in the evolution of social behaviours, the relatedness between interacting individuals is influenced by the spatial structure of the population. It is generally considered that in the 'viscous' population competition among individuals tends to suppress the evolution of altruism. We consider that more complex interactions produce specific spatial patterns in the presence of competitive interaction, which could alter the process of kin selection in a given space. Here, we theoretically studied the joint evolution of altruism and resource exploitation in a spatially structured population. The simulations indicated that joint evolution can result in self-organisation of regularly arranged cluster structures, which creates a new 'level of selection', and significantly promotes the evolution of altruism through a promotion of kin selection. The analysis also suggested synergetic effects of the joint evolution of two traits, including an evolutionary suicide of the population.}, } @article {pmid29244566, year = {2018}, author = {Lehtonen, J}, title = {The Price Equation, Gradient Dynamics, and Continuous Trait Game Theory.}, journal = {The American naturalist}, volume = {191}, number = {1}, pages = {146-153}, doi = {10.1086/694891}, pmid = {29244566}, issn = {1537-5323}, mesh = {*Biological Evolution ; *Game Theory ; *Genetic Fitness ; Models, Genetic ; }, abstract = {A recent article convincingly nominated the Price equation as the fundamental theorem of evolution and used it as a foundation to derive several other theorems. A major section of evolutionary theory that was not addressed is that of game theory and gradient dynamics of continuous traits with frequency-dependent fitness. Deriving fundamental results in these fields under the unifying framework of the Price equation illuminates similarities and differences between approaches and allows a simple, unified view of game-theoretical and dynamic concepts. Using Taylor polynomials and the Price equation, I derive a dynamic measure of evolutionary change, a condition for singular points, the convergence stability criterion, and an alternative interpretation of evolutionary stability. Furthermore, by applying the Price equation to a multivariable Taylor polynomial, the direct fitness approach to kin selection emerges. Finally, I compare these results to the mean gradient equation of quantitative genetics and the canonical equation of adaptive dynamics.}, } @article {pmid29244555, year = {2018}, author = {Lion, S}, title = {Theoretical Approaches in Evolutionary Ecology: Environmental Feedback as a Unifying Perspective.}, journal = {The American naturalist}, volume = {191}, number = {1}, pages = {21-44}, doi = {10.1086/694865}, pmid = {29244555}, issn = {1537-5323}, mesh = {Adaptation, Biological ; *Biological Evolution ; Ecology/*methods ; Feedback ; *Game Theory ; Gene Frequency ; Genetic Fitness ; *Models, Genetic ; }, abstract = {Evolutionary biology and ecology have a strong theoretical underpinning, and this has fostered a variety of modeling approaches. A major challenge of this theoretical work has been to unravel the tangled feedback loop between ecology and evolution. This has prompted the development of two main classes of models. While quantitative genetics models jointly consider the ecological and evolutionary dynamics of a focal population, a separation of timescales between ecology and evolution is assumed by evolutionary game theory, adaptive dynamics, and inclusive fitness theory. As a result, theoretical evolutionary ecology tends to be divided among different schools of thought, with different toolboxes and motivations. My aim in this synthesis is to highlight the connections between these different approaches and clarify the current state of theory in evolutionary ecology. Central to this approach is to make explicit the dependence on environmental dynamics of the population and evolutionary dynamics, thereby materializing the eco-evolutionary feedback loop. This perspective sheds light on the interplay between environmental feedback and the timescales of ecological and evolutionary processes. I conclude by discussing some potential extensions and challenges to our current theoretical understanding of eco-evolutionary dynamics.}, } @article {pmid29234885, year = {2018}, author = {Gleichsner, AM and Reinhart, K and Minchella, DJ}, title = {The influence of related and unrelated co-infections on parasite dynamics and virulence.}, journal = {Oecologia}, volume = {186}, number = {2}, pages = {555-564}, pmid = {29234885}, issn = {1432-1939}, mesh = {Animals ; *Coinfection ; Host-Parasite Interactions ; *Parasites ; *Parasitic Diseases ; Virulence ; }, abstract = {Many parasitic infections increase the morbidity and mortality of host populations. Interactions between co-infecting parasites can influence virulence, the damage done to a host. Previous studies investigating the impacts of parasite co-infection on hosts have been limited by their inability to control parasite dosage, use consistent virulence metrics, or verify co-infection status. This study used molecular tools, known infection dosage, and multiple assessments over time to test whether parasite relatedness can predict virulence in co-infections, as well as whether competitive interactions between different parasite strains within a host are predictable over time. In addition, we examined the impacts of other parasite traits, such as infectivity, as alternative predictors of virulence and competition outcomes. Hosts with single-strain (related) parasite infections were found to have lower virulence in terms of host and parasite reproduction, supporting kin selection predictions. However, these infections also resulted in higher host mortality. We argue that mortality should not be used as a measurement of virulence in parasite systems that castrate hosts. Hosts were more susceptible to mixed strain (unrelated) parasite infections, indicating that co-infections may make resistance more costly to hosts. Co-infections were dynamic, with changes in parasite dominance over the course of the infection. The more infective parasite strain appeared to suppress the less infective strain, ultimately increasing host longevity. Our findings suggest that unrelated, or more diverse, parasite infections are associated with higher virulence, but that studies must consider their methodology and possible alternative explanations beyond kin selection to understand virulence outcomes.}, } @article {pmid29206171, year = {2017}, author = {Levin, SR and West, SA}, title = {Kin Selection in the RNA World.}, journal = {Life (Basel, Switzerland)}, volume = {7}, number = {4}, pages = {}, pmid = {29206171}, issn = {2075-1729}, abstract = {Various steps in the RNA world required cooperation. Why did life's first inhabitants, from polymerases to synthetases, cooperate? We develop kin selection models of the RNA world to answer these questions. We develop a very simple model of RNA cooperation and then elaborate it to model three relevant issues in RNA biology: (1) whether cooperative RNAs receive the benefits of cooperation; (2) the scale of competition in RNA populations; and (3) explicit replicator diffusion and survival. We show: (1) that RNAs are likely to express partial cooperation; (2) that RNAs will need mechanisms for overcoming local competition; and (3) in a specific example of RNA cooperation, persistence after replication and offspring diffusion allow for cooperation to overcome competition. More generally, we show how kin selection can unify previously disparate answers to the question of RNA world cooperation.}, } @article {pmid29195838, year = {2018}, author = {Sanches, VH and Kuraoka, DVH and Almeida, PR and Goldman, C}, title = {A phenomenological analysis of eco-evolutionary coupling under dilution.}, journal = {Journal of theoretical biology}, volume = {438}, number = {}, pages = {156-164}, doi = {10.1016/j.jtbi.2017.11.019}, pmid = {29195838}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Ecosystem ; *Models, Biological ; Numerical Analysis, Computer-Assisted ; Saccharomyces cerevisiae/metabolism ; Time Factors ; }, abstract = {Evolutionary dynamics experienced by mixed microbial populations of cooperators and cheaters has been examined in experiments in the literature using a protocol of periodic dilution to investigate the properties of resilience and adaptability to environmental changes. Data depicted on an appropriate phase diagram indicate, among other features, a stable equilibrium point at which cooperators and cheaters coexist (Sanchez and Gore, 2013). We present here a phenomenological analysis of these data focusing on an eco-evolutionary-game perspective. To that end, we work on an extension of the model proposed in Tao and Cressman (2007). It's original version takes into account changes of the total population density while the individuals experience a pairwise Prisoners Dilemma game. The extension devised here contains a dilution parameter to conform with the experimental procedure, in addition to a term accounting for Allee effects. In contrast to other descriptions proposed in similar contexts, however, the model here does not account for assortative encounters, group or kin selection. Nonetheless, it describes surprisingly well both qualitatively and quantitatively the features of the observed phase diagram. We discuss these results in terms of the behavior of an effective payoff matrix defined accordingly.}, } @article {pmid29179582, year = {2017}, author = {Zhang, J}, title = {Is Support of Censoring Controversial Media Content for the Good of Others? Sexual Strategies and Support of Censoring Pro-Alcohol Advertising.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {15}, number = {4}, pages = {1474704917742808}, pmid = {29179582}, issn = {1474-7049}, mesh = {Adolescent ; Adult ; *Advertising ; *Alcohol Drinking ; *Alcoholic Beverages ; Female ; Humans ; Male ; *Sexual Behavior ; United States ; Young Adult ; }, abstract = {At least in the United States, there are widespread concerns with advertising that encourages alcohol consumption, and previous research explains those concerns as aiming to protect others from the harm of excessive alcohol use.[1] Drawing on sexual strategies theory, we hypothesized that support of censoring pro-alcohol advertising is ultimately self-benefiting regardless of its altruistic effect at a proximate level. Excessive drinking positively correlates with having casual sex, and casual sex threatens monogamy, one of the major means with which people adopting a long-term sexual strategy increase their inclusive fitness. Then, one way for long-term strategists to protect monogamy, and thus their reproductive interest is to support censoring pro-alcohol advertising, thereby preventing others from becoming excessive drinkers (and consequently having casual sex) under media influence. Supporting this hypothesis, three studies consistently showed that restricted sociosexuality positively correlated with support of censoring pro-alcohol advertising before and after various value-, ideological-, and moral-foundation variables were controlled for. Also as predicted, Study 3 revealed a significant indirect effect of sociosexuality on censorship support through perceived media influence on others but not through perceived media influence on self. These findings further supported a self-interest analysis of issue opinions, extended third-person-effect research on support of censoring pro-alcohol advertising, and suggested a novel approach to analyzing media censorship support.}, } @article {pmid29166167, year = {2017}, author = {Riehl, C}, title = {Kinship and Incest Avoidance Drive Patterns of Reproductive Skew in Cooperatively Breeding Birds.}, journal = {The American naturalist}, volume = {190}, number = {6}, pages = {774-785}, doi = {10.1086/694411}, pmid = {29166167}, issn = {1537-5323}, mesh = {Animals ; Birds/*genetics/*physiology ; Female ; *Inbreeding ; Male ; Reproduction/physiology ; *Social Behavior ; Species Specificity ; }, abstract = {Social animals vary in how reproduction is divided among group members, ranging from monopolization by a dominant pair (high skew) to equal sharing by cobreeders (low skew). Despite many theoretical models, the ecological and life-history factors that generate this variation are still debated. Here I analyze data from 83 species of cooperatively breeding birds, finding that kinship within the breeding group is a powerful predictor of reproductive sharing across species. Societies composed of nuclear families have significantly higher skew than those that contain unrelated members, a pattern that holds for both multimale and multifemale groups. Within-species studies confirm this, showing that unrelated subordinates of both sexes are more likely to breed than related subordinates are. Crucially, subordinates in cooperative groups are more likely to breed if they are unrelated to the opposite-sex dominant, whereas relatedness to the same-sex dominant has no effect. This suggests that incest avoidance, rather than suppression by dominant breeders, may be an important proximate mechanism limiting reproduction by subordinates. Overall, these results support the ultimate evolutionary logic behind concessions models of skew-namely, that related subordinates gain indirect fitness benefits from helping at the nests of kin, so a lower direct reproductive share is required for selection to favor helping over dispersal-but not the proximate mechanism of dominant control assumed by these models.}, } @article {pmid29142115, year = {2017}, author = {Lymbery, SJ and Simmons, LW}, title = {Males harm females less when competing with familiar relatives.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1867}, pages = {}, pmid = {29142115}, issn = {1471-2954}, mesh = {*Aggression ; Animals ; Coleoptera/*physiology ; Female ; Male ; *Sexual Behavior, Animal ; }, abstract = {Sexual conflict occurs when reproductive partners have different fitness optima, and can lead to the evolution of traits in one sex that inflict fitness costs on the opposite sex. Recently, it has been proposed that antagonism by males towards females should be reduced when they compete with relatives, because reducing the future productivity of a female would result in an indirect fitness cost for a harmful male. We tested this prediction in the seed beetle Callosobruchus maculatus, the males of which harm females with genital spines and pre-copulatory harassment. We compared lifespan, lifetime egg production and lifetime offspring production among females housed with groups of males that varied in their familiarity and relatedness. Females produced significantly more eggs and offspring when grouped with males who were both related and familiar to each other. There was no effect of male relatedness or familiarity on female lifespan. Our results suggest that males plastically adjust their harmfulness towards females in response to changes in inclusive fitness payoffs, and that in this species both genetic relatedness and social familiarity mediate this effect.}, } @article {pmid29134064, year = {2017}, author = {Bertolaso, M and Dieli, AM}, title = {Cancer and intercellular cooperation.}, journal = {Royal Society open science}, volume = {4}, number = {10}, pages = {170470}, pmid = {29134064}, issn = {2054-5703}, abstract = {The major transitions approach in evolutionary biology has shown that the intercellular cooperation that characterizes multicellular organisms would never have emerged without some kind of multilevel selection. Relying on this view, the Evolutionary Somatic view of cancer considers cancer as a breakdown of intercellular cooperation and as a loss of the balance between selection processes that take place at different levels of organization (particularly single cell and individual organism). This seems an elegant unifying framework for healthy organism, carcinogenesis, tumour proliferation, metastasis and other phenomena such as ageing. However, the gene-centric version of Darwinian evolution, which is often adopted in cancer research, runs into empirical problems: proto-tumoural and tumoural features in precancerous cells that would undergo 'natural selection' have proved hard to demonstrate; cells are radically context-dependent, and some stages of cancer are poorly related to genetic change. Recent perspectives propose that breakdown of intercellular cooperation could depend on 'fields' and other higher-level phenomena, and could be even mutations independent. Indeed, the field would be the context, allowing (or preventing) genetic mutations to undergo an intra-organism process analogous to natural selection. The complexities surrounding somatic evolution call for integration between multiple incomplete frameworks for interpreting intercellular cooperation and its pathologies.}, } @article {pmid29118238, year = {2017}, author = {Smith, D}, title = {Correction to 'O brother, where art thou? Investment in siblings for inclusive fitness benefits, not father absence, predicts earlier age at menarche'.}, journal = {Biology letters}, volume = {13}, number = {11}, pages = {}, pmid = {29118238}, issn = {1744-957X}, } @article {pmid29109471, year = {2017}, author = {Gardner, A and Úbeda, F}, title = {The meaning of intragenomic conflict.}, journal = {Nature ecology & evolution}, volume = {1}, number = {12}, pages = {1807-1815}, doi = {10.1038/s41559-017-0354-9}, pmid = {29109471}, issn = {2397-334X}, mesh = {*Biological Evolution ; Genetic Fitness ; *Genome ; Models, Genetic ; *Selection, Genetic ; }, abstract = {Recent years have seen an explosion of interest in genes that function for their own good and to the detriment of other genes that reside in the same genome. Such intragenomic conflicts are increasingly recognized to underpin maladaptation and disease. However, progress has been impeded by a lack of clear understanding regarding what intragenomic conflict actually means, and an associated obscurity concerning its fundamental drivers. Here we develop a general theory of intragenomic conflict in which genes are viewed as inclusive-fitness-maximizing agents that come into conflict when their inclusive-fitness interests disagree. This yields a classification of all intragenomic conflicts into three categories according to whether genes disagree about where they have come from, where they are going, or where they currently are. We illustrate each of these three basic categories, survey and classify all known forms of intragenomic conflict, and discuss the implications for organismal maladaptation and human disease.}, } @article {pmid29080969, year = {2018}, author = {Tornero, E and Sánchez-Romera, JF and Morosoli, JJ and Vázquez, A and Gómez, Á and Ordoñana, JR}, title = {Altruistic Behavior among Twins : Willingness to Fight and Self-Sacrifice for Their Closest Relatives.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {29}, number = {1}, pages = {1-12}, pmid = {29080969}, issn = {1936-4776}, support = {19479/PI/14//Fundación Séneca/ ; PSI2014-56680-R//Ministerio de Economía y Competitividad/ ; PSI2015-67754-P//Ministerio de Economía y Competitividad/ ; }, mesh = {Adult ; Aggression/*psychology ; *Altruism ; Female ; Humans ; Male ; *Sibling Relations ; Twins, Dizygotic/*psychology ; Twins, Monozygotic/*psychology ; }, abstract = {According to kin selection theory, indirect reproductive advantages may induce individuals to care for others with whom they share genes by common descent, and the amount of care, including self-sacrifice, will increase with the proportion of genes shared. Twins represent a natural situation in which this hypothesis can be tested. Twin pairs experience the same early environment because they were born and raised at the same time and in the same family but their genetic relatedness differs depending on zygosity. We compared the degree of willingness to fight and sacrifice for the co-twin among monozygotic (MZ) and dizygotic (DZ) pairs in a sample of 1443 same-sex and opposite-sex twins. We also analyzed the effect of the subject's gender and that of the co-twin on those altruistic behaviors. Results partly supported the postulated explanation. MZ twins (who share nearly their entire genome) were significantly more likely than DZ twins (who on average share half of their segregating genes) to self-sacrifice for their co-twins, but zygosity did not affect willingness to fight for him/her. The genders of the subject and of the co-twin, not genetic relatedness, were the best predictors of aggressive altruistic intentions.}, } @article {pmid29073100, year = {2017}, author = {Bebbington, K and Kingma, SA and Fairfield, EA and Dugdale, HL and Komdeur, J and Spurgin, LG and Richardson, DS}, title = {Kinship and familiarity mitigate costs of social conflict between Seychelles warbler neighbors.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {43}, pages = {E9036-E9045}, pmid = {29073100}, issn = {1091-6490}, mesh = {*Aggression ; Animal Distribution ; Animals ; Ecosystem ; Female ; Genotype ; Male ; Passeriformes/*genetics/physiology ; Recognition, Psychology ; Seychelles ; *Territoriality ; }, abstract = {Because virtually all organisms compete with others in their social environment, mechanisms that reduce conflict between interacting individuals are crucial for the evolution of stable families, groups, and societies. Here, we tested whether costs of social conflict over territorial space between Seychelles warblers (Acrocephalus sechellensis) are mitigated by kin-selected (genetic relatedness) or mutualistic (social familiarity) mechanisms. By measuring longitudinal changes in individuals' body mass and telomere length, we demonstrated that the fitness costs of territoriality are driven by a complex interplay between relatedness, familiarity, local density, and sex. Physical fights were less common at territory boundaries shared between related or familiar males. In line with this, male territory owners gained mass when living next to related or familiar males and also showed less telomere attrition when living next to male kin. Importantly, these relationships were strongest in high-density areas of the population. Males also had more rapid telomere attrition when living next to unfamiliar male neighbors, but mainly when relatedness to those neighbors was also low. In contrast, neither kinship nor familiarity was linked to body mass or telomere loss in female territory owners. Our results indicate that resolving conflict over territorial space through kin-selected or mutualistic pathways can reduce both immediate energetic costs and permanent somatic damage, thus providing an important mechanism to explain fine-scale population structure and cooperation between different social units across a broad range of taxa.}, } @article {pmid29061969, year = {2017}, author = {Kingma, SA}, title = {Direct benefits explain interspecific variation in helping behaviour among cooperatively breeding birds.}, journal = {Nature communications}, volume = {8}, number = {1}, pages = {1094}, pmid = {29061969}, issn = {2041-1723}, mesh = {Animals ; Behavior, Animal/*physiology ; Birds/*physiology ; Breeding ; Cooperative Behavior ; Helping Behavior ; Nesting Behavior/physiology ; Species Specificity ; }, abstract = {Kin selection theory provides one important explanation for seemingly altruistic helping behaviour by non-breeding subordinates in cooperative breeding animals. However, it cannot explain why helpers in many species provide energetically costly care to unrelated offspring. Here, I use comparative analyses to show that direct fitness benefits of helping others, associated with future opportunities to breed in the resident territory, are responsible for the widespread variation in helping effort (offspring food provisioning) and kin discrimination across cooperatively breeding birds. In species where prospects of territory inheritance are larger, subordinates provide more help, and, unlike subordinates that cannot inherit a territory, do not preferentially direct care towards related offspring. Thus, while kin selection can underlie helping behaviour in some species, direct benefits are much more important than currently recognised and explain why unrelated individuals provide substantial help in many bird species.}, } @article {pmid29055381, year = {2017}, author = {Riordan, DV}, title = {Mimetic Theory and the evolutionary paradox of schizophrenia: The archetypal scapegoat hypothesis.}, journal = {Medical hypotheses}, volume = {108}, number = {}, pages = {101-107}, doi = {10.1016/j.mehy.2017.08.010}, pmid = {29055381}, issn = {1532-2777}, mesh = {*Altruism ; *Biological Evolution ; Cultural Characteristics ; Environment ; Humans ; *Interpersonal Relations ; Language ; Models, Biological ; Models, Psychological ; Religion ; Risk ; Schizophrenia/*physiopathology ; *Social Behavior ; Social Stigma ; Violence ; }, abstract = {Schizophrenia poses an evolutionary paradox, being genetically mediated yet associated with reduced fecundity. Numerous hypotheses have attempted to address this, but few describe how the schizophrenic phenotype itself might constitute an evolutionary adaptation. This paper draws on René Girard's theory on human origins, which claims that humans evolved a tendency to mimic both the desires and the behaviours of each other (mimetic theory). This would have promoted social cohesion and co-operation, but at the cost of intra-group rivalry and conflict. The mimetic dynamic would have escalated such conflicts into reciprocal internecine violence, threatening the survival of the entire group. Girard theorised that the "scapegoat mechanism" emerged, by which means such violence was curtailed by the unanimity of "all against one", thus allowing the mimetic impulse to safely evolve further, making language and complex social behaviours possible. Whereas scapegoating may have emerged in the entire population, and any member of a community could be scapegoated if necessary, this paper proposes that the scapegoat mechanism would have worked better in groups containing members who exhibited traits, recognised by all others, which singled them out as victims. Schizophrenia may be a functional adaptation, similar in evolutionary terms to altruism, in that it may have increased inclusive fitness, by providing scapegoat victims, the choice of whom was likely to be agreed upon unanimously, even during internecine conflict, thus restoring order and protecting the group from self-destruction. This evolutionary hypothesis, uses Girardian anthropology to combine the concept of the schizophrenic as religious shaman with that of the schizophrenic as scapegoat. It may help to reconcile divergent philosophical concepts of mental illness, and also help us to better understand, and thus counter, social exclusion and stigmatisation.}, } @article {pmid29046373, year = {2017}, author = {Smith, D}, title = {O brother, where art thou? Investment in siblings for inclusive fitness benefits, not father absence, predicts earlier age at menarche.}, journal = {Biology letters}, volume = {13}, number = {10}, pages = {}, pmid = {29046373}, issn = {1744-957X}, support = {G9815508/MRC_/Medical Research Council/United Kingdom ; MC_PC_15018/MRC_/Medical Research Council/United Kingdom ; }, mesh = {Adolescent ; Age Factors ; Child ; England ; *Fathers ; Female ; Humans ; Longitudinal Studies ; Male ; Menarche/*physiology ; *Paternal Deprivation ; *Siblings ; }, abstract = {Numerous studies have indicated that father absence is associated with earlier age at menarche, with many evolutionary theories assuming that father absence is a causal factor that accelerates reproductive development. However, an alternative interpretation suggests that offspring may reproduce earlier in the presence of half- or step-siblings as the indirect fitness benefits to investing in them are lower, relative to delaying reproduction and investing in full siblings. From this perspective, father absence may perform no causal role in facilitating the onset of menarche. Using data from the Avon Longitudinal Study of Parents and Children, I find that individuals with only half- or step-siblings reach reproductive age earlier than those with only full siblings, with no independent effect of father absence. These results suggest that inclusive fitness benefits to investing in siblings, rather than father absence, may predict variation in age at menarche. These results provide a greater understanding of the adaptive mechanisms involved in reproductive decision-making, as well as potential implications for human life-history evolution and cooperative breeding more broadly.}, } @article {pmid29021183, year = {2017}, author = {Levin, SR and West, SA}, title = {The evolution of cooperation in simple molecular replicators.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1864}, pages = {}, pmid = {29021183}, issn = {1471-2954}, mesh = {Animals ; Bacteria/genetics ; Biological Evolution ; *Evolution, Molecular ; *Genome ; *Life History Traits ; Models, Genetic ; Social Behavior ; }, abstract = {In order for the first genomes to evolve, independent replicators had to act cooperatively, with some reducing their own replication rate to help copy others. It has been argued that limited diffusion explains this early cooperation. However, social evolution models have shown that limited diffusion on its own often does not favour cooperation. Here we model early replicators using social evolution tools. We show that: (i) replicators can be considered to be cooperating as a result of kin selection; (ii) limited diffusion on its own does not favour cooperation; and (iii) the addition of overlapping generations, probably a general trait of molecular replicators, promotes cooperation. These results suggest key life-history features in the evolution of the genome and that the same factors can favour cooperation across the entire tree of life.}, } @article {pmid28977660, year = {2019}, author = {Gong, X and Zhang, F and Fung, HH}, title = {Are Older Adults More Willing to Donate? The Roles of Donation Form and Social Relationship.}, journal = {The journals of gerontology. Series B, Psychological sciences and social sciences}, volume = {74}, number = {3}, pages = {440-448}, doi = {10.1093/geronb/gbx099}, pmid = {28977660}, issn = {1758-5368}, mesh = {Aged ; *Altruism ; Cultural Characteristics ; Decision Making/physiology ; *Family Relations ; Female ; *Gift Giving ; Humans ; Male ; Middle Aged ; *Psychological Distance ; Social Behavior ; Young Adult ; }, abstract = {OBJECTIVES: Whether older adults are more prosocial than younger adults has been under debate. In the current study, we investigated how age differences in prosocial behaviors varied across different contextual factors, that is, donation form, kinship, and social distance.

METHODS: To achieve this purpose, 89 younger and 66 older adults took part in a hypothetical donation task in which they were asked to donate money and time to relatives and nonrelatives at various social distances.

RESULTS: The results showed that, compared to younger adults, (a) older adults donated less to nonrelatives (regardless of the donation form), but donated a similar amount (in money) or even donated more (in time) to relatives; (b) older adults displayed higher levels of kin selection (favoring relatives over nonrelatives) in both monetary and time donations; and (c) older adults showed higher levels of social discounting (favoring socially close over distant others) in monetary but not time donation.

DISCUSSION: The study underscored the importance of contextual factors in understanding age differences in prosocial behaviors such as donation.}, } @article {pmid28957516, year = {2017}, author = {Van Cleve, J}, title = {Stags, Hawks, and Doves: Social Evolution Theory and Individual Variation in Cooperation.}, journal = {Integrative and comparative biology}, volume = {57}, number = {3}, pages = {566-579}, doi = {10.1093/icb/icx071}, pmid = {28957516}, issn = {1557-7023}, mesh = {Animals ; *Biological Evolution ; Cooperative Behavior ; *Game Theory ; Individuality ; *Social Behavior ; }, abstract = {One of the triumphs of evolutionary biology is the discovery of robust mechanisms that promote the evolution of cooperative behaviors even when cooperation reduces the fertility or survival of cooperators. These mechanisms include, kin selection, reciprocity, and direct benefits to cooperation that are often nonlinear. Though they have been extensively studied separately, investigating the joint action of these mechanisms has been more difficult. Moreover, how these mechanisms shape variation in cooperation is not well known. Such variation is crucial for understanding the evolution of behavioral syndromes and animal personality. Here, I use the tools of kin selection and evolutionary game theory to build a framework that integrates these mechanisms for pairwise social interactions. Using relatedness as a measure of the strength of kin selection, responsiveness as a measure of reciprocity, and synergy as a measure of payoff nonlinearity, I show how different combinations of these three parameters produce directional selection for or against cooperation or variation in levels of cooperation via stabilizing or diversifying selection. Moreover, each of these outcomes maps uniquely to one of four classic games from evolutionary game theory, which means that modulating relatedness, responsiveness, and synergy effectively transforms the payoff matrix from one the evolutionary game to another. Assuming that cooperation exacts a fertility cost on cooperators and provides a fertility benefit to social partners, a prisoner's dilemma game and directional selection against cooperation occur when relatedness and responsiveness are low and synergy is not too positive. Enough positive synergy in these conditions generates a stag-hunt game and diversifying selection. High levels of relatedness or responsiveness turn cooperation from a fitness cost into a fitness benefit, which produces a mutualism game and directional selection for cooperation when synergy is not too negative. Sufficiently negative synergy in this case creates a hawk-dove game and stabilizing selection for cooperation. I extend the results with relatedness and synergy to social groups and show that how group size changes the effect of relatedness and synergy on selection for cooperation depends on how the per capita benefit of cooperation changes with group size. Together, these results provide a general framework with which to generate comparative predictions that can be tested using quantitative genetic techniques and experimental techniques that manipulate investment in cooperation. These predictions will help us understand both interspecific variation in cooperation as well as within-population and within-group variation in cooperation related to behavioral syndromes.}, } @article {pmid28957466, year = {2017}, author = {Harpur, BA and Dey, A and Albert, JR and Patel, S and Hines, HM and Hasselmann, M and Packer, L and Zayed, A}, title = {Queens and Workers Contribute Differently to Adaptive Evolution in Bumble Bees and Honey Bees.}, journal = {Genome biology and evolution}, volume = {9}, number = {9}, pages = {2395-2402}, pmid = {28957466}, issn = {1759-6653}, mesh = {*Adaptation, Physiological ; Animals ; Bees/*genetics/physiology ; *Evolution, Molecular ; Female ; Genetic Fitness ; Male ; Selection, Genetic ; *Social Behavior ; }, abstract = {Eusociality represents a major transition in evolution and is typified by cooperative brood care and reproductive division of labor between generations. In bees, this division of labor allows queens and workers to phenotypically specialize. Worker traits associated with helping are thought to be crucial to the fitness of a eusocial lineage, and recent studies of honey bees (genus Apis) have found that adaptively evolving genes often have worker-biased expression patterns. It is unclear however if worker-biased genes are disproportionately acted on by strong positive selection in all eusocial insects. We undertook a comparative population genomics study of bumble bees (Bombus) and honey bees to quantify natural selection on queen- and worker-biased genes across two levels of social complexity. Despite sharing a common eusocial ancestor, genes, and gene groups with the highest levels of positive selection were often unique within each genus, indicating that life history and the environment, but not sociality per se, drives patterns of adaptive molecular evolution. We uncovered differences in the contribution of queen- and worker-biased genes to adaptive evolution in bumble bees versus honey bees. Unlike honey bees, where worker-biased genes are enriched for signs of adaptive evolution, genes experiencing positive selection in bumble bees were predominately expressed by reproductive foundresses during the initial solitary-founding stage of colonies. Our study suggests that solitary founding is a major selective pressure and that the loss of queen totipotency may cause a change in the architecture of selective pressures upon the social insect genome.}, } @article {pmid28954911, year = {2017}, author = {Qi, XG and Huang, K and Fang, G and Grueter, CC and Dunn, DW and Li, YL and Ji, W and Wang, XY and Wang, RT and Garber, PA and Li, BG}, title = {Male cooperation for breeding opportunities contributes to the evolution of multilevel societies.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1863}, pages = {}, pmid = {28954911}, issn = {1471-2954}, mesh = {Animals ; *Breeding ; Colobinae/genetics/*physiology ; *Cooperative Behavior ; Male ; Phylogeny ; *Sexual Behavior, Animal ; Telemetry ; }, abstract = {A small number of primate species including snub-nosed monkeys (colobines), geladas (papionins) and humans live in multilevel societies (MLSs), in which multiple one-male polygamous units (OMUs) coexist to form a band, and non-breeding males associate in bachelor groups. Phylogenetic reconstructions indicate that the papionin MLS appears to have evolved through internal fissioning of large mixed-sex groups, whereas the colobine MLS evolved through the aggregation of small, isolated OMUs. However, how agonistic males maintain tolerance under intensive competition over limited breeding opportunities remains unclear. Using a combination of behavioural analysis, satellite telemetry and genetic data, we quantified the social network of males in a bachelor group of golden snub-nosed monkeys. The results show a strong effect of kinship on social bonds among bachelors. Their interactions ranged from cooperation to agonism, and were regulated by access to mating partners. We suggest that an 'arms race' between breeding males' collective defence against usurpation attempts by bachelor males and bachelor males' aggregative offence to obtain reproductive opportunities has selected for larger group size on both sides. The results provide insight into the role that kin selection plays in shaping inter-male cohesion which facilities the evolution of multilevel societies. These findings have implications for understanding human social evolution, as male-male bonds are a hallmark of small- and large-scale human societies.}, } @article {pmid28954904, year = {2017}, author = {Bshary, R and Raihani, NJ}, title = {Helping in humans and other animals: a fruitful interdisciplinary dialogue.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1863}, pages = {}, pmid = {28954904}, issn = {1471-2954}, mesh = {*Altruism ; Animals ; Biological Evolution ; *Cooperative Behavior ; *Helping Behavior ; Humans ; Interdisciplinary Research ; }, abstract = {Humans are arguably unique in the extent and scale of cooperation with unrelated individuals. While pairwise interactions among non-relatives occur in some non-human species, there is scant evidence of the large-scale, often unconditional prosociality that characterizes human social behaviour. Consequently, one may ask whether research on cooperation in humans can offer general insights to researchers working on similar questions in non-human species, and whether research on humans should be published in biology journals. We contend that the answer to both of these questions is yes. Most importantly, social behaviour in humans and other species operates under the same evolutionary framework. Moreover, we highlight how an open dialogue between different fields can inspire studies on humans and non-human species, leading to novel approaches and insights. Biology journals should encourage these discussions rather than drawing artificial boundaries between disciplines. Shared current and future challenges are to study helping in ecologically relevant contexts in order to correctly interpret how payoff matrices translate into inclusive fitness, and to integrate mechanisms into the hitherto largely functional theory. We can and should study human cooperation within a comparative framework in order to gain a full understanding of the evolution of helping.}, } @article {pmid28950415, year = {2017}, author = {Ben-Shlomo, R}, title = {Invasiveness, chimerism and genetic diversity.}, journal = {Molecular ecology}, volume = {26}, number = {23}, pages = {6502-6509}, doi = {10.1111/mec.14364}, pmid = {28950415}, issn = {1365-294X}, mesh = {Adaptation, Biological/*genetics ; Animals ; Biological Evolution ; *Chimerism ; Founder Effect ; Genetic Fitness ; *Genetic Variation ; *Introduced Species ; Models, Genetic ; Urochordata/genetics ; }, abstract = {Adaptation for invasiveness should comprise the capability to exploit and prosper in a wide range of ecological conditions and is therefore expected to be associated with a certain level of genetic diversity. Paradoxically, however, invasive populations are established by only a few founders, resulting in low genetic diversity. As a conceivable way of attaining high genetic diversity and high variance of gene expression even when a small number of founders is involved in invasiveness, I suggest here chimerism, a fusion between different individuals-a common phenomenon found in numerous phyla. The composite entity offers the chimeric organism genetic flexibility and higher inclusive fitness that depends on the joint genomic fitness of the original partners. The ability to form a chimeric entity is also applied to subsequent generations, and consequently, the level of genetic diversity does not decline over generations of population establishment following invasion.}, } @article {pmid28884795, year = {2017}, author = {McDonald, GC and Farine, DR and Foster, KR and Biernaskie, JM}, title = {Assortment and the analysis of natural selection on social traits.}, journal = {Evolution; international journal of organic evolution}, volume = {71}, number = {11}, pages = {2693-2702}, doi = {10.1111/evo.13365}, pmid = {28884795}, issn = {1558-5646}, support = {BB/M013995/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/L006081/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/L009587/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Birds/genetics/physiology ; Coleoptera/genetics/physiology ; Genetic Fitness ; *Models, Genetic ; *Phenotype ; *Selection, Genetic ; *Social Behavior ; }, abstract = {A central problem in evolutionary biology is to determine whether and how social interactions contribute to natural selection. A key method for phenotypic data is social selection analysis, in which fitness effects from social partners contribute to selection only when there is a correlation between the traits of individuals and their social partners (nonrandom phenotypic assortment). However, there are inconsistencies in the use of social selection that center around the measurement of phenotypic assortment. Here, we use data analysis and simulations to resolve these inconsistencies, showing that: (i) not all measures of assortment are suitable for social selection analysis; and (ii) the interpretation of assortment, and how to detect nonrandom assortment, will depend on the scale at which it is measured. We discuss links to kin selection theory and provide a practical guide for the social selection approach.}, } @article {pmid28870603, year = {2017}, author = {Corley, M and Valeggia, C and Fernandez-Duque, E}, title = {Hormonal correlates of development and natal dispersal in wild female owl monkeys (Aotus azarae) of Argentina.}, journal = {Hormones and behavior}, volume = {96}, number = {}, pages = {42-51}, pmid = {28870603}, issn = {1095-6867}, support = {P30 AG012836/AG/NIA NIH HHS/United States ; R24 HD044964/HD/NICHD NIH HHS/United States ; }, mesh = {Animal Distribution/*physiology ; Animals ; Animals, Wild ; Aotidae/*growth & development/*metabolism ; Argentina ; Feces/chemistry ; Female ; Gonadal Steroid Hormones/analysis/*metabolism ; Male ; Reproduction/physiology ; Sexual Maturation/physiology ; }, abstract = {Pair-living and socially monogamous primates typically do not reproduce before dispersing. It is currently unclear whether this reproductive suppression is due to endocrine or behavioral mechanisms. Cooperatively breeding taxa, like callitrichids, may forego reproduction in natal groups because they reap inclusive fitness benefits and/or they are avoiding inbreeding. However, neither of these benefits of delayed reproduction appear to adequately explain the lack of reproduction prior to leaving the natal group in pair-living monogamous species. In this study, we determined whether wild Azara's owl monkeys (Aotus azarae) in the Argentinean Chaco establish reproductive maturity prior to dispersing. We utilized 635 fecal extracts to characterize reproductive hormone profiles of 11 wild juvenile and subadult females using enzyme immunoassays. Subadult females showed hormone profiles indicative of ovulatory cycling and had mean PdG and E1G concentrations approximately five times higher than juveniles. Contrary to expectations from the inbreeding avoidance hypothesis, female owl monkeys do not delay puberty, but rather commence ovarian cycling while residing in their natal group. Still, subadults appear to have a period during which they experience irregular, non-conceptive cycles prior to reproducing. Commencing these irregular cycles in the natal group may allow them to develop a state of suspended readiness, which could be essential to securing a mate, while avoiding costs of ranging solitarily. Our results indicate that reproductive suppression in female owl monkeys is not due to endocrine suppression. We suggest that adults likely use behavioral mechanisms to prevent subadults from reproducing with unrelated adult males in their natal group.}, } @article {pmid28845069, year = {2017}, author = {Engelhardt, A and Muniz, L and Perwitasari-Farajallah, D and Widdig, A}, title = {Highly Polymorphic Microsatellite Markers for the Assessment of Male Reproductive Skew and Genetic Variation in Critically Endangered Crested Macaques (Macaca nigra).}, journal = {International journal of primatology}, volume = {38}, number = {4}, pages = {672-691}, pmid = {28845069}, issn = {0164-0291}, abstract = {Genetic analyses based on noninvasively collected samples have become an important tool for evolutionary biology and conservation. Crested macaques (Macaca nigra), endemic to Sulawesi, Indonesia, are important for our understanding of primate evolution as Sulawesi macaques represent an exceptional example of primate adaptive radiation. Crested macaques are also Critically Endangered. However, to date we know very little about their genetics. The aim of our study was to find and validate microsatellite markers useful for evolutionary, conservation, and other genetic studies on wild crested macaques. Using fecal samples of 176 wild macaques living in the Tangkoko Reserve, Sulawesi, we identified 12 polymorphic microsatellite loci through cross-species polymerase chain reaction amplification with later modification of some of these primers. We tested their suitability by investigating and exploring patterns of paternity, observed heterozygosity, and evidence for inbreeding. We assigned paternity to 63 of 65 infants with high confidence. Among cases with solved paternity, we found no evidence of extragroup paternity and natal breeding. We found a relatively steep male reproductive skew B index of 0.330 ± 0.267; mean ± SD) and mean alpha paternity of 65% per year with large variation across groups and years (29-100%). Finally, we detected an excess in observed heterozygosity and no evidence of inbreeding across our three study groups, with an observed heterozygosity of 0.766 ± 0.059 and expected heterozygosity of 0.708 ± 0.059, and an inbreeding coefficient of -0.082 ± 0.035. Our results indicate that the selected markers are useful for genetic studies on wild crested macaques, and possibly also on other Sulawesi and closely related macaques. They further suggest that the Tangkoko population of crested macaques is still genetically variable despite its small size, isolation, and the species' reproductive patterns. This gives us hope that other endangered primate species living in small, isolated populations may also retain a healthy gene pool, at least in the short term.}, } @article {pmid28841690, year = {2017}, author = {Kücklich, M and Möller, M and Marcillo, A and Einspanier, A and Weiß, BM and Birkemeyer, C and Widdig, A}, title = {Different methods for volatile sampling in mammals.}, journal = {PloS one}, volume = {12}, number = {8}, pages = {e0183440}, pmid = {28841690}, issn = {1932-6203}, mesh = {Animal Communication ; Animals ; Callithrix/*physiology ; Female ; Gas Chromatography-Mass Spectrometry ; Odorants ; Volatile Organic Compounds/*analysis ; }, abstract = {Previous studies showed that olfactory cues are important for mammalian communication. However, many specific compounds that convey information between conspecifics are still unknown. To understand mechanisms and functions of olfactory cues, olfactory signals such as volatile compounds emitted from individuals need to be assessed. Sampling of animals with and without scent glands was typically conducted using cotton swabs rubbed over the skin or fur and analysed by gas chromatography-mass spectrometry (GC-MS). However, this method has various drawbacks, including a high level of contaminations. Thus, we adapted two methods of volatile sampling from other research fields and compared them to sampling with cotton swabs. To do so we assessed the body odor of common marmosets (Callithrix jacchus) using cotton swabs, thermal desorption (TD) tubes and, alternatively, a mobile GC-MS device containing a thermal desorption trap. Overall, TD tubes comprised most compounds (N = 113), with half of those compounds being volatile (N = 52). The mobile GC-MS captured the fewest compounds (N = 35), of which all were volatile. Cotton swabs contained an intermediate number of compounds (N = 55), but very few volatiles (N = 10). Almost all compounds found with the mobile GC-MS were also captured with TD tubes (94%). Hence, we recommend TD tubes for state of the art sampling of body odor of mammals or other vertebrates, particularly for field studies, as they can be easily transported, stored and analysed with high performance instruments in the lab. Nevertheless, cotton swabs capture compounds which still may contribute to the body odor, e.g. after bacterial fermentation, while profiles from mobile GC-MS include only the most abundant volatiles of the body odor.}, } @article {pmid28839927, year = {2017}, author = {Gardner, A}, title = {The purpose of adaptation.}, journal = {Interface focus}, volume = {7}, number = {5}, pages = {20170005}, pmid = {28839927}, issn = {2042-8898}, abstract = {A central feature of Darwin's theory of natural selection is that it explains the purpose of biological adaptation. Here, I: emphasize the scientific importance of understanding what adaptations are for, in terms of facilitating the derivation of empirically testable predictions; discuss the population genetical basis for Darwin's theory of the purpose of adaptation, with reference to Fisher's 'fundamental theorem of natural selection'; and show that a deeper understanding of the purpose of adaptation is achieved in the context of social evolution, with reference to inclusive fitness and superorganisms.}, } @article {pmid28812668, year = {2017}, author = {Chak, STC and Duffy, JE and Hultgren, KM and Rubenstein, DR}, title = {Evolutionary transitions towards eusociality in snapping shrimps.}, journal = {Nature ecology & evolution}, volume = {1}, number = {4}, pages = {96}, doi = {10.1038/s41559-017-0096}, pmid = {28812668}, issn = {2397-334X}, abstract = {Animal social organization varies from complex societies where reproduction is dominated by a single individual (eusociality) to those where reproduction is more evenly distributed among group members (communal breeding). Yet, how simple groups transition evolutionarily to more complex societies remains unclear. Competing hypotheses suggest that eusociality and communal breeding are alternative evolutionary endpoints, or that communal breeding is an intermediate stage in the transition towards eusociality. We tested these alternative hypotheses in sponge-dwelling shrimps, Synalpheus spp. Although species varied continuously in reproductive skew, they clustered into pair-forming, communal and eusocial categories based on several demographic traits. Evolutionary transition models suggested that eusocial and communal species are discrete evolutionary endpoints that evolved independently from pair-forming ancestors along alternative paths. This 'family-centred' origin of eusociality parallels observations in insects and vertebrates, reinforcing the role of kin selection in the evolution of eusociality and suggesting a general model of animal social evolution.}, } @article {pmid28794215, year = {2017}, author = {Le Page, S and Sepil, I and Flintham, E and Pizzari, T and Carazo, P and Wigby, S}, title = {Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1860}, pages = {}, pmid = {28794215}, issn = {1471-2954}, support = {BB/K014544/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Courtship ; Drosophila melanogaster/*physiology ; Female ; Male ; Reproduction ; *Sexual Behavior, Animal ; }, abstract = {Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.}, } @article {pmid28791162, year = {2017}, author = {Birch, J}, title = {The inclusive fitness controversy: finding a way forward.}, journal = {Royal Society open science}, volume = {4}, number = {7}, pages = {170335}, pmid = {28791162}, issn = {2054-5703}, abstract = {This paper attempts to reconcile critics and defenders of inclusive fitness by constructing a synthesis that does justice to the insights of both. I argue that criticisms of the regression-based version of Hamilton's rule, although they undermine its use for predictive purposes, do not undermine its use as an organizing framework for social evolution research. I argue that the assumptions underlying the concept of inclusive fitness, conceived as a causal property of an individual organism, are unlikely to be exactly true in real populations, but they are approximately true given a specific type of weak selection that Hamilton took, on independent grounds, to be responsible for the cumulative assembly of complex adaptation. Finally, I reflect on the uses and limitations of 'design thinking' in social evolution research.}, } @article {pmid28766161, year = {2017}, author = {Amici, F and Mimó, MC and von Borell, C and Bueno-Guerra, N}, title = {Meerkats (Suricata suricatta) fail to prosocially donate food in an experimental set-up.}, journal = {Animal cognition}, volume = {20}, number = {6}, pages = {1059-1066}, doi = {10.1007/s10071-017-1122-6}, pmid = {28766161}, issn = {1435-9456}, mesh = {Animals ; *Feeding Behavior ; Female ; Herpestidae/*psychology ; Male ; Motivation ; *Social Behavior ; Video Recording ; }, abstract = {Although humans are usually believed to be prosocial, the evolutionary origins of prosociality are largely debated. One hypothesis is that cooperative breeding has been one major precursor to the emergence of prosociality. In vertebrates, however, experimental evidence of prosociality has been mainly gathered in non-human primates. In this study, we tested the cooperative breeding hypothesis in cooperative breeding meerkats (Suricata suricatta). In particular, we tested whether meerkats take into account partners' benefits when distributing food rewards. Nine individuals were presented with two platforms baited with different food distributions (providing food to themselves, to a partner or both). In all conditions, the decision to operate the apparatus was based on the presence of food on the subject's side, and not on the possible benefits to partners. Despite being cooperative breeders, meerkats in this study failed to be prosocial, suggesting that prosociality in this species may be limited to specific contexts.}, } @article {pmid28765001, year = {2017}, author = {Marcillo, A and Jakimovska, V and Widdig, A and Birkemeyer, C}, title = {Comparison of two common adsorption materials for thermal desorption gas chromatography - mass spectrometry of biogenic volatile organic compounds.}, journal = {Journal of chromatography. A}, volume = {1514}, number = {}, pages = {16-28}, doi = {10.1016/j.chroma.2017.07.005}, pmid = {28765001}, issn = {1873-3778}, mesh = {Adsorption ; Animals ; Gas Chromatography-Mass Spectrometry/*methods/standards ; Gases/chemistry ; Odorants/analysis ; Polymers/analysis/chemistry ; Reference Standards ; Solvents/chemistry ; Temperature ; Volatile Organic Compounds/*analysis/standards ; }, abstract = {Volatile organic compounds (VOCs) are commonly collected from gaseous samples by adsorption to materials such as the porous polymer Tenax TA. Adsorbed compounds are subsequently released from these materials by thermal desorption (TD) and separated then by gas chromatography (GC) with flame ionization (FID) or mass spectrometry (MS) detection. Tenax TA is known to be particularly suitable for non-polar to semipolar volatiles, however, many volatiles from environmental and biological samples possess a rather polar character. Therefore, we tested if the polymer XAD-2, which so far is widely used to adsorb organic compounds from aqueous and organic solvents, could provide a broader coverage for (semi)polar VOCs during gas-phase sampling. Mixtures of volatile compounds covering a wide range of volatility (bp. 20-256°C) and different chemical classes were introduced by liquid spiking into sorbent tubes with one of the two porous polymers, Tenax TA or XAD-2, and analyzed by TD/GC-MS. At first, an internal standard mixture composed of 17 authentic standards was used to optimize desorption temperature with respect to sorbent degradation and loading time for calibration. Secondly, we tested the detectability of a complex standard mixture composed of 57 volatiles, most of them common constituents of the body odor of mammals. Moreover, the performance of XAD-2 compared with Tenax TA was assessed as limit of quantitation and linearity for the internal standard mixture and 33 compounds from the complex standard mixture. Volatiles were analyzed in a range between 0.01-∼250ng/tube depending on the compound and material. Lower limits of quantitation were between 0.01 and 3 ng±<25% RSD (R[2]>0.9). Interestingly, we found different kinetics for compound adsorption with XAD-2, and a partially better sensitivity in comparison with Tenax TA. For these analytes, XAD-2 might be recommended as an alternative of Tenax TA for TD/GC-MS analysis.}, } @article {pmid30283644, year = {2017}, author = {Bebbington, K and Kingma, SA}, title = {No evidence that kin selection increases the honesty of begging signals in birds.}, journal = {Evolution letters}, volume = {1}, number = {3}, pages = {132-137}, pmid = {30283644}, issn = {2056-3744}, abstract = {Providing plausible mechanisms to explain variation in the honesty of information communicated through offspring begging signals is fundamental to our understanding of parent-offspring conflict and the evolution of family life. A recently published research article used comparative analyses to investigate two long-standing hypotheses that may explain the evolution of begging behavior. The results suggested that direct competition between offspring for parental resources decreases begging honesty, whereas indirect, kin-selected benefits gained through saving parental resources for the production of future siblings increase begging honesty. However, we feel that evidence for a role of kin selection in this context is still missing. We present a combination of arguments and empirical tests to outline alternative sources of interspecific variation in offspring begging levels and discuss avenues for further research that can bring us closer to a complete understanding of the evolution of offspring signaling.}, } @article {pmid28739172, year = {2017}, author = {Thouzeau, V and Raymond, M}, title = {Emergence and maintenance of menopause in humans: A game theory model.}, journal = {Journal of theoretical biology}, volume = {430}, number = {}, pages = {229-236}, doi = {10.1016/j.jtbi.2017.07.019}, pmid = {28739172}, issn = {1095-8541}, mesh = {*Biological Evolution ; Family Characteristics ; Female ; *Game Theory ; Humans ; *Menopause ; Reproduction ; }, abstract = {Menopause, the permanent cessation of ovulation, occurs in women well before the end of their expected life span. Several adaptive hypotheses have been proposed to solve this evolutionary puzzle, each based on a possible fitness benefit derived from an early reproductive senescence, but no consensus has emerged. The construction of a game theory model allowed us to jointly study the main adaptive hypotheses in emergence and maintenance of menopause. Four classical hypotheses on the benefits of menopause were considered (decreased maternal mortality, increased grandmothering, decreased conflict over reproductive resources between older and younger females, and changes in their relatedness) plus a fifth one derived from a possible pleiotropic trade-off. Interestingly, the conditions for the emergence of menopause are more restrictive than those for its maintenance due to the social and familial changes induced by the occurrence of non-reproductive older women.}, } @article {pmid28711317, year = {2017}, author = {Mullon, C and Lehmann, L}, title = {Invasion fitness for gene-culture co-evolution in family-structured populations and an application to cumulative culture under vertical transmission.}, journal = {Theoretical population biology}, volume = {116}, number = {}, pages = {33-46}, doi = {10.1016/j.tpb.2017.06.003}, pmid = {28711317}, issn = {1096-0325}, mesh = {Adaptation, Physiological ; *Biological Evolution ; *Cultural Characteristics ; *Cultural Evolution ; Culture ; *Genetics, Behavioral ; Humans ; *Learning ; Models, Biological ; }, abstract = {Human evolution depends on the co-evolution between genetically determined behaviors and socially transmitted information. Although vertical transmission of cultural information from parent to offspring is common in hominins, its effects on cumulative cultural evolution are not fully understood. Here, we investigate gene-culture co-evolution in a family-structured population by studying the invasion fitness of a mutant allele that influences a deterministic level of cultural information (e.g., amount of knowledge or skill) to which diploid carriers of the mutant are exposed in subsequent generations. We show that the selection gradient on such a mutant, and the concomitant level of cultural information it generates, can be evaluated analytically under the assumption that the cultural dynamic has a single attractor point, thereby making gene-culture co-evolution in family-structured populations with multigenerational effects mathematically tractable. We apply our result to study how genetically determined phenotypes of individual and social learning co-evolve with the level of adaptive information they generate under vertical transmission. We find that vertical transmission increases adaptive information due to kin selection effects, but when information is transmitted as efficiently between family members as between unrelated individuals, this increase is moderate in diploids. By contrast, we show that the way resource allocation into learning trades off with allocation into reproduction (the "learning-reproduction trade-off") significantly influences levels of adaptive information. We also show that vertical transmission prevents evolutionary branching and may therefore play a qualitative role in gene-culture co-evolutionary dynamics. More generally, our analysis of selection suggests that vertical transmission can significantly increase levels of adaptive information under the biologically plausible condition that information transmission between relatives is more efficient than between unrelated individuals.}, } @article {pmid28699275, year = {2018}, author = {Phillips, T}, title = {The concepts of asymmetric and symmetric power can help resolve the puzzle of altruistic and cooperative behaviour.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {93}, number = {1}, pages = {457-468}, doi = {10.1111/brv.12352}, pmid = {28699275}, issn = {1469-185X}, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Cooperative Behavior ; Models, Biological ; }, abstract = {Evolutionary theory predicts competition in nature yet altruistic and cooperative behaviour appears to reduce the ability to compete in order to help others compete better. This evolutionary puzzle is usually explained by kin selection where close relatives perform altruistic and cooperative acts to help each other and by reciprocity theory (i.e. direct, indirect and generalized reciprocity) among non-kin. Here, it is proposed that the concepts of asymmetry and symmetry in power and dominance are critical if we are ever to resolve the puzzle of altruism and cooperation towards non-kin. Asymmetry in power and dominance is likely to emerge under competition in nature as individuals strive to gain greater access to the scarce resources needed to survive and reproduce successfully. Yet asymmetric power presents serious problems for reciprocity theory in that a dominant individual faces a temptation to cheat in interactions with subordinates that is likely to far outweigh any individual selective benefits gained through reciprocal mechanisms. Furthermore, action taken by subordinates to deter non-reciprocation by dominants is likely to prove prohibitively costly to their fitness, making successful enforcement of reciprocal mechanisms unlikely. It is also argued here that many apparently puzzling forms of cooperation observed in nature (e.g. cooperative breeding in which unrelated subordinates help dominants to breed) might be best explained by asymmetry in power and dominance. Once it is recognized that individuals in these cooperative interactions are subject to the constraints and opportunities imposed on them by asymmetric power then they can be seen as pursuing a 'least bad' strategy to promote individual fitness - one that is nevertheless consistent with evolutionary theory. The concept of symmetric power also provides important insights. It can inhibit reciprocal mechanisms in the sense that symmetric power makes it easier for a cheat to appropriate common resources while incurring fewer penalties. Nevertheless under certain restrictive conditions, symmetric power is seen as likely to promote direct reciprocity through 'tit for tat'.}, } @article {pmid28681487, year = {2017}, author = {Wloch-Salamon, DM and Fisher, RM and Regenberg, B}, title = {Division of labour in the yeast: Saccharomyces cerevisiae.}, journal = {Yeast (Chichester, England)}, volume = {34}, number = {10}, pages = {399-406}, doi = {10.1002/yea.3241}, pmid = {28681487}, issn = {1097-0061}, mesh = {Adaptation, Physiological ; Apoptosis ; Biofilms/growth & development ; Biological Evolution ; Phenotype ; Resting Phase, Cell Cycle ; Saccharomyces cerevisiae/genetics/*physiology ; }, abstract = {Division of labour between different specialized cell types is a central part of how we describe complexity in multicellular organisms. However, it is increasingly being recognized that division of labour also plays an important role in the lives of predominantly unicellular organisms. Saccharomyces cerevisiae displays several phenotypes that could be considered a division of labour, including quiescence, apoptosis and biofilm formation, but they have not been explicitly treated as such. We discuss each of these examples, using a definition of division of labour that involves phenotypic variation between cells within a population, cooperation between cells performing different tasks and maximization of the inclusive fitness of all cells involved. We then propose future research directions and possible experimental tests using S. cerevisiae as a model organism for understanding the genetic mechanisms and selective pressures that can lead to the evolution of the very first stages of a division of labour. Copyright © 2017 John Wiley & Sons, Ltd.}, } @article {pmid28672203, year = {2017}, author = {Caniglia, G}, title = {"How complex and even perverse the real world can be": W.D. Hamilton's early work on social wasps (1964-1968).}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {64}, number = {}, pages = {41-52}, doi = {10.1016/j.shpsc.2017.06.005}, pmid = {28672203}, issn = {1879-2499}, mesh = {Animals ; Biological Evolution ; *Selection, Genetic ; *Social Behavior ; *Wasps ; }, abstract = {William D. Hamilton's name is often connected to important theoretical accomplishments, from the theory of inclusive fitness and kin selection to the so-called Hamilton's rule and the haplodiploidy hypothesis. This article asks: How did Hamilton attempt to test his theory and hypothesis against the complexity of the biological world? The article reconstructs Hamilton's empirical work with social wasps between 1963 and 1968, the years before and after the publication of the groundbreaking "The Genetical Evolution of Social Behavior" in 1964. It points out the centrality of Hamilton's work on wasps and shows how the British scientist attempted to test theories and hypotheses with naturalistic, developmental, and physiological observations as well as, at times, with experimental manipulations. The article offers a new perspective on the history of the scientific understanding of the evolution of social behavior. In contrast to existing narratives, this perspective emphasizes the importance of empirical work-e.g. natural history, physiology, comparative anatomy-which is often obscured by a nearly exclusive focus on theoretical developments in this field.}, } @article {pmid28659767, year = {2017}, author = {Couto, A and Mitra, A and Thiéry, D and Marion-Poll, F and Sandoz, JC}, title = {Hornets Have It: A Conserved Olfactory Subsystem for Social Recognition in Hymenoptera?.}, journal = {Frontiers in neuroanatomy}, volume = {11}, number = {}, pages = {48}, pmid = {28659767}, issn = {1662-5129}, abstract = {Eusocial Hymenoptera colonies are characterized by the presence of altruistic individuals, which rear their siblings instead of their own offspring. In the course of evolution, such sterile castes are thought to have emerged through the process of kin selection, altruistic traits being transmitted to following generation if they benefit relatives. By allowing kinship recognition, the detection of cuticular hydrocarbons (CHCs) might be instrumental for kin selection. In carpenter ants, a female-specific olfactory subsystem processes CHC information through antennal detection by basiconic sensilla. It is still unclear if other families of eusocial Hymenoptera use the same subsystem for sensing CHCs. Here, we examined the existence of such a subsystem in Vespidae (using the hornet Vespa velutina), a family in which eusociality emerged independently of ants. The antennae of both males and female hornets contain large basiconic sensilla. Sensory neurons from the large basiconic sensilla exclusively project to a conspicuous cluster of small glomeruli in the antennal lobe, with anatomical and immunoreactive features that are strikingly similar to those of the ant CHC-sensitive subsystem. Extracellular electrophysiological recordings further show that sensory neurons within hornet basiconic sensilla preferentially respond to CHCs. Although this subsystem is not female-specific in hornets, the observed similarities with the olfactory system of ants are striking. They suggest that the basiconic sensilla subsystem could be an ancestral trait, which may have played a key role in the advent of eusociality in these hymenopteran families by allowing kin recognition and the production of altruistic behaviors toward relatives.}, } @article {pmid28622934, year = {2017}, author = {Kessler, SE and Bonnell, TR and Byrne, RW and Chapman, CA}, title = {Selection to outsmart the germs: The evolution of disease recognition and social cognition.}, journal = {Journal of human evolution}, volume = {108}, number = {}, pages = {92-109}, doi = {10.1016/j.jhevol.2017.02.009}, pmid = {28622934}, issn = {1095-8606}, mesh = {*Biological Evolution ; *Cognition ; *Delivery of Health Care ; Disease Transmission, Infectious/*prevention & control ; Family ; Humans ; *Social Behavior ; }, abstract = {The emergence of providing care to diseased conspecifics must have been a turning point during the evolution of hominin sociality. On a population level, care may have minimized the costs of socially transmitted diseases at a time of increasing social complexity, although individual care-givers probably incurred increased transmission risks. We propose that care-giving likely originated within kin networks, where the costs may have been balanced by fitness increases obtained through caring for ill kin. We test a novel hypothesis of hominin cognitive evolution in which disease may have selected for the cognitive ability to recognize when a conspecific is infected. Because diseases may produce symptoms that are likely detectable via the perceptual-cognitive pathways integral to social cognition, we suggest that disease recognition and social cognition may have evolved together. Using agent-based modeling, we test 1) under what conditions disease can select for increasing disease recognition and care-giving among kin, 2) whether providing care produces greater selection for cognition than an avoidance strategy, and 3) whether care-giving alters the progression of the disease through the population. The greatest selection was produced by diseases with lower risks to the care-giver and prevalences low enough not to disrupt the kin networks. When care-giving and avoidance strategies were compared, only care-giving reduced the severity of the disease outbreaks and subsequent population crashes. The greatest selection for increased cognitive abilities occurred early in the model runs when the outbreaks and population crashes were most severe. Therefore, over the course of human evolution, repeated introductions of novel diseases into naïve populations could have produced sustained selection for increased disease recognition and care-giving behavior, leading to the evolution of increased cognition, social complexity, and, eventually, medical care in humans. Finally, we lay out predictions derived from our disease recognition hypothesis that we encourage paleoanthropologists, bioarchaeologists, primatologists, and paleogeneticists to test.}, } @article {pmid28596113, year = {2017}, author = {Wild, G and Korb, J}, title = {Evolution of delayed dispersal and subsequent emergence of helping, with implications for cooperative breeding.}, journal = {Journal of theoretical biology}, volume = {427}, number = {}, pages = {53-64}, doi = {10.1016/j.jtbi.2017.05.038}, pmid = {28596113}, issn = {1095-8541}, mesh = {Animals ; *Biological Evolution ; *Breeding ; Models, Biological ; }, abstract = {Cooperative breeding occurs when individuals help raise the offspring of others. It is widely accepted that help displayed by cooperative breeders emerged only after individuals' tendency to delay dispersal had become established. We use this idea as a basis for two inclusive-fitness models: one for the evolution of delayed dispersal, and a second for the subsequent emergence of helpful behavior exhibited by non-breeding individuals. We focus on a territorial species in a saturated environment, and allow territories to be inherited by non-breeding individuals who have delayed dispersal. Our first model predicts that increased survivorship and increased fecundity both provide an incentive to non-breeding individuals to delay dispersal, and stay near their natal territory for some period of time. Predictions from the first model can be well understood by ignoring complications arising from competition among relatives. Our second model shows that effects on relatives play a primary role in the advantage of helping. In addition, the second model predicts that increased survivorship and fecundity promote the emergence of help. Together, our models lead us to conclude that the emergence of cooperative-breeding systems is made easier by life-history features associated with high survivorship and fecundity. We discuss the implications of our conclusions for life-history-based hypotheses of cooperative breeding and social evolution.}, } @article {pmid28512224, year = {2017}, author = {Nowak, MA and McAvoy, A and Allen, B and Wilson, EO}, title = {The general form of Hamilton's rule makes no predictions and cannot be tested empirically.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {22}, pages = {5665-5670}, pmid = {28512224}, issn = {1091-6490}, abstract = {Hamilton's rule asserts that a trait is favored by natural selection if the benefit to others, [Formula: see text], multiplied by relatedness, [Formula: see text], exceeds the cost to self, [Formula: see text] Specifically, Hamilton's rule states that the change in average trait value in a population is proportional to [Formula: see text] This rule is commonly believed to be a natural law making important predictions in biology, and its influence has spread from evolutionary biology to other fields including the social sciences. Whereas many feel that Hamilton's rule provides valuable intuition, there is disagreement even among experts as to how the quantities [Formula: see text], [Formula: see text], and [Formula: see text] should be defined for a given system. Here, we investigate a widely endorsed formulation of Hamilton's rule, which is said to be as general as natural selection itself. We show that, in this formulation, Hamilton's rule does not make predictions and cannot be tested empirically. It turns out that the parameters [Formula: see text] and [Formula: see text] depend on the change in average trait value and therefore cannot predict that change. In this formulation, which has been called "exact and general" by its proponents, Hamilton's rule can "predict" only the data that have already been given.}, } @article {pmid28508537, year = {2018}, author = {Boomsma, JJ and Gawne, R}, title = {Superorganismality and caste differentiation as points of no return: how the major evolutionary transitions were lost in translation.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {93}, number = {1}, pages = {28-54}, doi = {10.1111/brv.12330}, pmid = {28508537}, issn = {1469-185X}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Insecta/*genetics/*physiology ; Selection, Genetic ; *Social Behavior ; }, abstract = {More than a century ago, William Morton Wheeler proposed that social insect colonies can be regarded as superorganisms when they have morphologically differentiated reproductive and nursing castes that are analogous to the metazoan germ-line and soma. Following the rise of sociobiology in the 1970s, Wheeler's insights were largely neglected, and we were left with multiple new superorganism concepts that are mutually inconsistent and uninformative on how superorganismality originated. These difficulties can be traced to the broadened sociobiological concept of eusociality, which denies that physical queen-worker caste differentiation is a universal hallmark of superorganismal colonies. Unlike early evolutionary naturalists and geneticists such as Weismann, Huxley, Fisher and Haldane, who set out to explain the acquisition of an unmated worker caste, the goal of sociobiology was to understand the evolution of eusociality, a broad-brush convenience category that covers most forms of cooperative breeding. By lumping a diverse spectrum of social systems into a single category, and drawing attention away from the evolution of distinct quantifiable traits, the sociobiological tradition has impeded straightforward connections between inclusive fitness theory and the major evolutionary transitions paradigm for understanding irreversible shifts to higher organizational complexity. We evaluate the history by which these inconsistencies accumulated, develop a common-cause approach for understanding the origins of all major transitions in eukaryote hierarchical complexity, and use Hamilton's rule to argue that they are directly comparable. We show that only Wheeler's original definition of superorganismality can be unambiguously linked to irreversible evolutionary transitions from context-dependent reproductive altruism to unconditional differentiation of permanently unmated castes in the ants, corbiculate bees, vespine wasps and higher termites. We argue that strictly monogamous parents were a necessary, albeit not sufficient condition for all transitions to superorganismality, analogous to single-zygote bottlenecking being a necessary but not sufficient condition for the convergent origins of complex soma across multicellular eukaryotes. We infer that conflict reduction was not a necessary condition for the origin of any of these major transitions, and conclude that controversies over the status of inclusive fitness theory primarily emanate from the arbitrarily defined sociobiological concepts of superorganismality and eusociality, not from the theory itself.}, } @article {pmid28503187, year = {2017}, author = {Lee, CC and Nakao, H and Tseng, SP and Hsu, HW and Lin, GL and Tay, JW and Billen, J and Ito, F and Lee, CY and Lin, CC and Yang, CS}, title = {Worker reproduction of the invasive yellow crazy ant Anoplolepis gracilipes.}, journal = {Frontiers in zoology}, volume = {14}, number = {}, pages = {24}, pmid = {28503187}, issn = {1742-9994}, abstract = {BACKGROUND: Reproductive division of labor is one of the key features of social insects. Queens are adapted for reproduction while workers are adapted for foraging and colony maintenance. In many species, however, workers retain functional ovaries and can lay unfertilized male eggs or trophic eggs. Here we report for the first time on the occurrence of physogastric workers and apparent worker reproduction in the invasive yellow crazy ant Anoplolepis gracilipes (Fr. Smith). We further examined the reproductive potential and nutritional role of physogastric workers through multidisciplinary approaches including morphological characterization, laboratory manipulation, genetic analysis and behavioral observation.

RESULTS: Egg production with two types of eggs, namely reproductive and trophic eggs, by physogastric workers was found. The reproductive egg was confirmed to be haploid and male-destined, suggesting that the workers produced males via arrhenotokous parthenogenesis as no spermatheca was discovered. Detailed observations suggested that larvae were mainly fed with trophic eggs. Along with consumption of trophic eggs by queens and other castes as part of their diet, the vital role of physogastric workers as "trophic specialist" is confirmed.

CONCLUSION: We propose that adaptive advantages derived from worker reproduction for A. gracilipes may include 1) trophic eggs provisioned by physogastric workers likely assist colonies of A. gracilipes in overcoming unfavorable conditions such as paucity of food during critical founding stage; 2) worker-produced males are fertile and thus might offer an inclusive fitness advantage for the doomed orphaned colony.}, } @article {pmid28487486, year = {2017}, author = {Dugatkin, LA}, title = {Long reach of inclusive fitness.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {20}, pages = {5067-5068}, pmid = {28487486}, issn = {1091-6490}, mesh = {Biological Evolution ; *Genetic Fitness ; Models, Genetic ; *Selection, Genetic ; }, } @article {pmid28469021, year = {2017}, author = {Cornioley, T and Jenouvrier, S and Börger, L and Weimerskirch, H and Ozgul, A}, title = {Fathers matter: male body mass affects life-history traits in a size-dimorphic seabird.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1854}, pages = {}, pmid = {28469021}, issn = {1471-2954}, mesh = {Animals ; Birds/*physiology ; *Body Size ; Climate Change ; Fathers ; Female ; Male ; Population Dynamics ; Reproduction ; *Sex Characteristics ; }, abstract = {One of the predicted consequences of climate change is a shift in body mass distributions within animal populations. Yet body mass, an important component of the physiological state of an organism, can affect key life-history traits and consequently population dynamics. Over the past decades, the wandering albatross-a pelagic seabird providing bi-parental care with marked sexual size dimorphism-has exhibited an increase in average body mass and breeding success in parallel with experiencing increasing wind speeds. To assess the impact of these changes, we examined how body mass affects five key life-history traits at the individual level: adult survival, breeding probability, breeding success, chick mass and juvenile survival. We found that male mass impacted all traits examined except breeding probability, whereas female mass affected none. Adult male survival increased with increasing mass. Increasing adult male mass increased breeding success and mass of sons but not of daughters. Juvenile male survival increased with their chick mass. These results suggest that a higher investment in sons by fathers can increase their inclusive fitness, which is not the case for daughters. Our study highlights sex-specific differences in the effect of body mass on the life history of a monogamous species with bi-parental care.}, } @article {pmid28469015, year = {2017}, author = {Vitikainen, EIK and Marshall, HH and Thompson, FJ and Sanderson, JL and Bell, MBV and Gilchrist, JS and Hodge, SJ and Nichols, HJ and Cant, MA}, title = {Biased escorts: offspring sex, not relatedness explains alloparental care patterns in a cooperative breeder.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1854}, pages = {}, pmid = {28469015}, issn = {1471-2954}, mesh = {Animals ; *Cooperative Behavior ; Female ; *Helping Behavior ; Herpestidae/*physiology ; Male ; }, abstract = {Kin selection theory predicts that animals should direct costly care where inclusive fitness gains are highest. Individuals may achieve this by directing care at closer relatives, yet evidence for such discrimination in vertebrates is equivocal. We investigated patterns of cooperative care in banded mongooses, where communal litters are raised by adult 'escorts' who form exclusive caring relationships with individual pups. We found no evidence that escorts and pups assort by parentage or relatedness. However, the time males spent escorting increased with increasing relatedness to the other group members, and to the pup they had paired with. Thus, we found no effect of relatedness in partner choice, but (in males) increasing helping effort with relatedness once partner choices had been made. Unexpectedly, the results showed clear assortment by sex, with female carers being more likely to tend to female pups, and male carers to male pups. This sex-specific assortment in helping behaviour has potential lifelong impacts on individual development and may impact the future size and composition of natal groups and dispersing cohorts. Where relatedness between helpers and recipients is already high, individuals may be better off choosing partners using other predictors of the costs and benefits of cooperation, without the need for possibly costly within-group kin discrimination.}, } @article {pmid30283638, year = {2017}, author = {O'Brien, EK and Wolf, JB}, title = {The coadaptation theory for genomic imprinting.}, journal = {Evolution letters}, volume = {1}, number = {1}, pages = {49-59}, pmid = {30283638}, issn = {2056-3744}, abstract = {Imprinted genes are peculiar in that expression of the two copies differs depending on whether the copy was maternally or paternally inherited. The discovery of this striking pattern of gene expression inspired myriad evolutionary theories, the most successful of which identify scenarios that create an asymmetry between the maternally and paternally inherited gene copies that favors silencing of one of the copies. Most notably, imprinting can evolve when gene dosage affects kin interactions (typically involving conflict) or when silencing enhances coadaptation by coordinating traits expressed by interacting kin. Although we have a well-established theory for the former process (the "Kinship Theory"), the coadaptation process has only been explored for the specific case of interactions between mothers and offspring. Here, we fill this critical gap in our understanding by developing a general "Coadaptation Theory" that explains how imprinting can evolve to coordinate interactions between all types of relatives. Using a simple model in which fitness of an individual is determined by an interaction between its own phenotype (and hence genotype) and that of its social partner(s), we find that when the relatedness of interactants differs through their maternally versus paternally inherited gene copies, then selection favors expression of the allele through which relatedness is higher. The predictions of this Coadaptation Theory potentially apply whenever a gene underlies traits that mediate the outcome of conspecific interactions, regardless of their mechanism or the type of organism, and therefore provide a potential explanation for enigmatic patterns of imprinting, including those underlying adult traits. By providing simple testable predictions that often directly contrast with those derived from alternative theories, our model should play an important role in consolidating our understanding of the evolution of imprinting across genes and species, which will ultimately provide crucial insights into imprinted gene function and dysfunction.}, } @article {pmid28439031, year = {2017}, author = {Thompson, FJ and Cant, MA and Marshall, HH and Vitikainen, EIK and Sanderson, JL and Nichols, HJ and Gilchrist, JS and Bell, MBV and Young, AJ and Hodge, SJ and Johnstone, RA}, title = {Explaining negative kin discrimination in a cooperative mammal society.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {20}, pages = {5207-5212}, pmid = {28439031}, issn = {1091-6490}, support = {BB/H022716/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Aggression/psychology ; Animals ; Behavior, Animal ; *Conflict, Psychological ; *Cooperative Behavior ; Dominance-Subordination ; Family/*psychology ; Female ; Game Theory ; Herpestidae/*psychology ; Inbreeding ; Male ; Reproduction ; Social Behavior ; }, abstract = {Kin selection theory predicts that, where kin discrimination is possible, animals should typically act more favorably toward closer genetic relatives and direct aggression toward less closely related individuals. Contrary to this prediction, we present data from an 18-y study of wild banded mongooses, Mungos mungo, showing that females that are more closely related to dominant individuals are specifically targeted for forcible eviction from the group, often suffering severe injury, and sometimes death, as a result. This pattern cannot be explained by inbreeding avoidance or as a response to more intense local competition among kin. Instead, we use game theory to show that such negative kin discrimination can be explained by selection for unrelated targets to invest more effort in resisting eviction. Consistent with our model, negative kin discrimination is restricted to eviction attempts of older females capable of resistance; dominants exhibit no kin discrimination when attempting to evict younger females, nor do they discriminate between more closely or less closely related young when carrying out infanticidal attacks on vulnerable infants who cannot defend themselves. We suggest that in contexts where recipients of selfish acts are capable of resistance, the usual prediction of positive kin discrimination can be reversed. Kin selection theory, as an explanation for social behavior, can benefit from much greater exploration of sequential social interactions.}, } @article {pmid28435860, year = {2017}, author = {Wang, Z and Jusup, M and Wang, RW and Shi, L and Iwasa, Y and Moreno, Y and Kurths, J}, title = {Onymity promotes cooperation in social dilemma experiments.}, journal = {Science advances}, volume = {3}, number = {3}, pages = {e1601444}, pmid = {28435860}, issn = {2375-2548}, abstract = {One of the most elusive scientific challenges for over 150 years has been to explain why cooperation survives despite being a seemingly inferior strategy from an evolutionary point of view. Over the years, various theoretical scenarios aimed at solving the evolutionary puzzle of cooperation have been proposed, eventually identifying several cooperation-promoting mechanisms: kin selection, direct reciprocity, indirect reciprocity, network reciprocity, and group selection. We report the results of repeated Prisoner's Dilemma experiments with anonymous and onymous pairwise interactions among individuals. We find that onymity significantly increases the frequency of cooperation and the median payoff per round relative to anonymity. Furthermore, we also show that the correlation between players' ranks and the usage of strategies (cooperation, defection, or punishment) underwent a fundamental shift, whereby more prosocial actions are rewarded with a better ranking under onymity. Our findings prove that reducing anonymity is a valid promoter of cooperation, leading to higher payoffs for cooperators and thus suppressing an incentive-anonymity-that would ultimately favor defection.}, } @article {pmid28419349, year = {2017}, author = {Warner, MR and Mikheyev, AS and Linksvayer, TA}, title = {Genomic Signature of Kin Selection in an Ant with Obligately Sterile Workers.}, journal = {Molecular biology and evolution}, volume = {34}, number = {7}, pages = {1780-1787}, pmid = {28419349}, issn = {1537-1719}, mesh = {Animals ; Ants/*genetics ; Behavior, Animal ; Biological Evolution ; Evolution, Molecular ; Family ; Genetics, Population/methods ; Genomics ; Infertility/genetics ; Metagenomics/methods ; Phenotype ; Reproduction/genetics ; Selection, Genetic/*genetics ; Social Behavior ; }, abstract = {Kin selection is thought to drive the evolution of cooperation and conflict, but the specific genes and genome-wide patterns shaped by kin selection are unknown. We identified thousands of genes associated with the sterile ant worker caste, the archetype of an altruistic phenotype shaped by kin selection, and then used population and comparative genomic approaches to study patterns of molecular evolution at these genes. Consistent with population genetic theoretical predictions, worker-upregulated genes experienced reduced selection compared with genes upregulated in reproductive castes. Worker-upregulated genes included more taxonomically restricted genes, indicating that the worker caste has recruited more novel genes, yet these genes also experienced reduced selection. Our study identifies a putative genomic signature of kin selection and helps to integrate emerging sociogenomic data with longstanding social evolution theory.}, } @article {pmid28417004, year = {2017}, author = {Jackson, CR and Groom, RJ and Jordan, NR and McNutt, JW}, title = {The effect of relatedness and pack size on territory overlap in African wild dogs.}, journal = {Movement ecology}, volume = {5}, number = {}, pages = {10}, pmid = {28417004}, issn = {2051-3933}, abstract = {BACKGROUND: Spacing patterns mediate competitive interactions between conspecifics, ultimately increasing fitness. The degree of territorial overlap between neighbouring African wild dog (Lycaon pictus) packs varies greatly, yet the role of factors potentially affecting the degree of overlap, such as relatedness and pack size, remain unclear. We used movement data from 21 wild dog packs to calculate the extent of territory overlap (20 dyads).

RESULTS: On average, unrelated neighbouring packs had low levels of overlap restricted to the peripheral regions of their 95% utilisation kernels. Related neighbours had significantly greater levels of peripheral overlap. Only one unrelated dyad included overlap between 75%-75% kernels, but no 50%-50% kernels overlapped. However, eight of 12 related dyads overlapped between their respective 75% kernels and six between the frequented 50% kernels. Overlap between these more frequented kernels confers a heightened likelihood of encounter, as the mean utilisation intensity per unit area within the 50% kernels was 4.93 times greater than in the 95% kernels, and 2.34 times greater than in the 75% kernels. Related packs spent significantly more time in their 95% kernel overlap zones than did unrelated packs. Pack size appeared to have little effect on overlap between related dyads, yet among unrelated neighbours larger packs tended to overlap more onto smaller packs' territories. However, the true effect is unclear given that the model's confidence intervals overlapped zero.

CONCLUSIONS: Evidence suggests that costly intraspecific aggression is greatly reduced between related packs. Consequently, the tendency for dispersing individuals to establish territories alongside relatives, where intensively utilised portions of ranges regularly overlap, may extend kin selection and inclusive fitness benefits from the intra-pack to inter-pack level. This natural spacing system can affect survival parameters and the carrying capacity of protected areas, having important management implications for intensively managed populations of this endangered species.}, } @article {pmid28410027, year = {2017}, author = {Kuijper, B and Johnstone, RA}, title = {How Sex-Biased Dispersal Affects Sexual Conflict over Care.}, journal = {The American naturalist}, volume = {189}, number = {5}, pages = {501-514}, doi = {10.1086/691330}, pmid = {28410027}, issn = {1537-5323}, mesh = {*Animal Distribution ; Animals ; *Conflict, Psychological ; Female ; Male ; *Maternal Behavior ; Models, Biological ; *Paternal Behavior ; Reproduction ; Sex Factors ; }, abstract = {Existing models of parental investment have mainly focused on interactions at the level of the family and have paid much less attention to the impact of population-level processes. Here we extend classical models of parental care to assess the impact of population structure and limited dispersal. We find that sex differences in dispersal substantially affect the amount of care provided by each parent, with the more philopatric sex providing the majority of care to young. This effect is most pronounced in highly viscous populations: in such cases, when classical models would predict stable biparental care, inclusion of a modest sex difference in dispersal leads to uniparental care by the philopatric sex. In addition, mating skew also affects sex differences in parental investment, with the more numerous sex providing most of the care. However, the effect of mating skew holds only when parents care for their own offspring. When individuals breed communally, we recover the previous finding that the more philopatric sex provides most of the care even when it is the rarer sex. We conclude that sex-biased dispersal is likely to be an important yet currently overlooked driver of sex differences in parental care.}, } @article {pmid28360453, year = {2017}, author = {Ruiz-Lambides, AV and Weiß, BM and Kulik, L and Stephens, C and Mundry, R and Widdig, A}, title = {Long-term analysis on the variance of extra-group paternities in rhesus macaques.}, journal = {Behavioral ecology and sociobiology}, volume = {71}, number = {4}, pages = {67}, pmid = {28360453}, issn = {0340-5443}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {ABSTRACT: Extra-group paternity (EGP) has been described in various mammalian species; however, little is known about which factors contribute to the variation in EGP, as the majority of studies were restricted in time and the number of groups considered. Using longitudinal demographic and genetic data, we aim to investigate which factors predict rates of EGP in the free-ranging rhesus macaque population of Cayo Santiago, Puerto Rico (USA). Of the 1649 infants considered which were born into six social groups over 9 years, we identified an average of 16% of infants resulting from EGPs. We tested the influence of group size, breeding group sex ratio, female reproductive synchrony, and group instability on the occurrence of EGPs. Our results suggest a tendency for EGPs to increase as the proportion of females increased in larger groups, but no such effect in smaller groups. Furthermore, as group instability and female reproductive synchrony decreased, the number of EGPs tended to increase. Our results support the hypothesis that group structure affects the occurrence of EGPs, which might be mediated by male mating opportunities, male monopolization potential, and/or female choice.

SIGNIFICANCE STATEMENT: In several species, both sexes seek alternative reproductive strategies to enhance their reproductive success. For instance, females may pursue EGPs to potentially increase genetic compatibility with males, or males may seek EGPs to improve their mating opportunities. Our longitudinal analysis, including demographic and genetic data over 9 years of six social groups of rhesus macaques, revealed high variation in the occurrence of EGPs across groups and years, and this variation tended to depend on group characteristics such as breeding group size, sex ratio, female synchrony, and group instability. The data suggest that group structure affects the number of EGPs in this group-living primate. Our results show that EGPs can affect the distribution of paternity within social groups and should be taken into account when assessing reproductive success.}, } @article {pmid28345048, year = {2017}, author = {Łukasiewicz, A and Szubert-Kruszyńska, A and Radwan, J}, title = {Kin selection promotes female productivity and cooperation between the sexes.}, journal = {Science advances}, volume = {3}, number = {3}, pages = {e1602262}, pmid = {28345048}, issn = {2375-2548}, mesh = {Acaridae/*genetics ; Animals ; *Biological Evolution ; Female ; Male ; *Models, Biological ; *Quantitative Trait, Heritable ; Reproduction/physiology ; *Selection, Genetic ; }, abstract = {Hamilton's theory of kin selection explains the evolution of costly traits that benefit other individuals by highlighting the fact that passing genes to offspring is not the only way of increasing the representation of those genes in subsequent generations: Genes are also shared with other classes of relatives. Consequently, any heritable trait that affects fitness of relatives should respond to kin selection. We tested this core prediction of kin selection theory by letting bulb mites (Rhizoglyphus robini) evolve in populations structured into groups of relatives or nonrelatives during the reproductive phase of the life cycle. In accordance with predictions derived from kin selection theory, we found that evolution in groups of relatives resulted in increased female reproductive output. This increase at least partly results from the evolution of male traits that elevate their partners' fecundity. Our results highlight the power and universality of kin selection.}, } @article {pmid28328991, year = {2017}, author = {Dušek, A and Bartoš, L and Sedláček, F}, title = {Pre-breeding food restriction promotes the optimization of parental investment in house mice, Mus musculus.}, journal = {PloS one}, volume = {12}, number = {3}, pages = {e0173985}, pmid = {28328991}, issn = {1932-6203}, mesh = {Animals ; Body Weight/physiology ; Breeding/methods ; Female ; Food ; Lactation/physiology ; Litter Size/physiology ; Mice ; Mice, Inbred ICR ; Parents ; Pregnancy ; Reproduction/*physiology ; Weaning ; }, abstract = {Litter size is one of the most reliable state-dependent life-history traits that indicate parental investment in polytocous (litter-bearing) mammals. The tendency to optimize litter size typically increases with decreasing availability of resources during the period of parental investment. To determine whether this tactic is also influenced by resource limitations prior to reproduction, we examined the effect of experimental, pre-breeding food restriction on the optimization of parental investment in lactating mice. First, we investigated the optimization of litter size in 65 experimental and 72 control families (mothers and their dependent offspring). Further, we evaluated pre-weaning offspring mortality, and the relationships between maternal and offspring condition (body weight), as well as offspring mortality, in 24 experimental and 19 control families with litter reduction (the death of one or more offspring). Assuming that pre-breeding food restriction would signal unpredictable food availability, we hypothesized that the optimization of parental investment would be more effective in the experimental rather than in the control mice. In comparison to the controls, the experimental mice produced larger litters and had a more selective (size-dependent) offspring mortality and thus lower litter reduction (the proportion of offspring deaths). Selective litter reduction helped the experimental mothers to maintain their own optimum condition, thereby improving the condition and, indirectly, the survival of their remaining offspring. Hence, pre-breeding resource limitations may have facilitated the mice to optimize their inclusive fitness. On the other hand, in the control females, the absence of environmental cues indicating a risky environment led to "maternal optimism" (overemphasizing good conditions at the time of breeding), which resulted in the production of litters of super-optimal size and consequently higher reproductive costs during lactation, including higher offspring mortality. Our study therefore provides the first evidence that pre-breeding food restriction promotes the optimization of parental investment, including offspring number and developmental success.}, } @article {pmid28322868, year = {2017}, author = {Ohtsuki, H and Wakano, JY and Kobayashi, Y}, title = {Inclusive fitness analysis of cumulative cultural evolution in an island-structured population.}, journal = {Theoretical population biology}, volume = {115}, number = {}, pages = {13-23}, doi = {10.1016/j.tpb.2017.03.001}, pmid = {28322868}, issn = {1096-0325}, mesh = {*Biological Evolution ; *Cultural Evolution ; *Genetic Fitness ; Humans ; Learning ; Reproduction ; }, abstract = {The success of humans on the globe is largely supported by our cultural excellence. Our culture is cumulative, meaning that it is improved from generation to generation. Previous works have revealed that two modes of learning, individual learning and social learning, play pivotal roles in the accumulation of culture. However, under the trade-off between learning and reproduction, one's investment into learning is easily exploited by those who copy the knowledge of skillful individuals and selfishly invest more efforts in reproduction. It has been shown that in order to prevent such a breakdown, the rate of vertical transmission (i.e. transmission from parents to their offspring) of culture must be unrealistically close to one. Here we investigate what if the population is spatially structured. In particular, we hypothesize that spatial structure should favor highly cumulative culture through endogenously arising high kinship. We employ Wright's island model and assume that cultural transmission occurs within a local island. Our inclusive fitness analysis reveals combined effects of direct fitness of the actor, indirect fitness through relatives in the current generation, and indirect fitness through relatives in future generations. The magnitude of those indirect benefits is measured by intergenerational coefficients of genetic relatedness. Our result suggests that the introduction of spatial structure raises the stationary level of culture in the population, but that the extent of its improvement compared with a well-mixed population is marginal unless spatial localization is extreme. Overall, our model implies that we need an alternative mechanism to explain highly cumulative culture of modern humans.}, } @article {pmid28298744, year = {2017}, author = {Welch, JJ}, title = {What's wrong with evolutionary biology?.}, journal = {Biology & philosophy}, volume = {32}, number = {2}, pages = {263-279}, pmid = {28298744}, issn = {0169-3867}, abstract = {There have been periodic claims that evolutionary biology needs urgent reform, and this article tries to account for the volume and persistence of this discontent. It is argued that a few inescapable properties of the field make it prone to criticisms of predictable kinds, whether or not the criticisms have any merit. For example, the variety of living things and the complexity of evolution make it easy to generate data that seem revolutionary (e.g. exceptions to well-established generalizations, or neglected factors in evolution), and lead to disappointment with existing explanatory frameworks (with their high levels of abstraction, and limited predictive power). It is then argued that special discontent stems from misunderstandings and dislike of one well-known but atypical research programme: the study of adaptive function, in the tradition of behavioural ecology. To achieve its goals, this research needs distinct tools, often including imaginary agency, and a partial description of the evolutionary process. This invites mistaken charges of narrowness and oversimplification (which come, not least, from researchers in other subfields), and these chime with anxieties about human agency and overall purpose. The article ends by discussing several ways in which calls to reform evolutionary biology actively hinder progress in the field.}, } @article {pmid28295032, year = {2017}, author = {Rode, NO and Soroye, P and Kassen, R and Rundle, HD}, title = {Air-borne genotype by genotype indirect genetic effects are substantial in the filamentous fungus Aspergillus nidulans.}, journal = {Heredity}, volume = {119}, number = {1}, pages = {1-7}, pmid = {28295032}, issn = {1365-2540}, mesh = {*Air Microbiology ; Aspergillus nidulans/*genetics/growth & development ; *Genetic Fitness ; *Genotype ; Microbial Interactions/*genetics ; Models, Genetic ; Phenotype ; }, abstract = {Genotype by genotype indirect genetic effects (G × G IGEs) occur when the phenotype of an individual is influenced by an interaction between its own genotype and those of neighbour individuals. Little is known regarding the relative importance of G × G IGEs compared with other forms of direct and indirect genetic effects. We quantified the relative importance of IGEs in the filamentous fungus Aspergillus nidulans, a species in which IGEs are likely to be important as air-borne social interactions are known to affect growth. We used a collection of distantly related wild isolates, lab strains and a set of closely related mutation accumulation lines to estimate the contribution of direct and indirect genetic effects on mycelium growth rate, a key fitness component. We found that indirect genetic effects were dominated by G × G IGEs that occurred primarily between a focal genotype and its immediate neighbour within a vertical stack, and these accounted for 11% of phenotypic variation. These results indicate that G × G IGEs may be substantial, at least in some systems, and that the evolutionary importance of these interactions may be underappreciated, especially in microbes. We advocate for a wider use of the IGE framework in both applied (for example, choice of varietal mixtures in plant breeding) and evolutionary genetics (kin selection/kin competition studies).}, } @article {pmid28280587, year = {2017}, author = {Murphy, GP and Van Acker, R and Rajcan, I and Swanton, CJ}, title = {Identity recognition in response to different levels of genetic relatedness in commercial soya bean.}, journal = {Royal Society open science}, volume = {4}, number = {1}, pages = {160879}, pmid = {28280587}, issn = {2054-5703}, abstract = {Identity recognition systems allow plants to tailor competitive phenotypes in response to the genetic relatedness of neighbours. There is limited evidence for the existence of recognition systems in crop species and whether they operate at a level that would allow for identification of different degrees of relatedness. Here, we test the responses of commercial soya bean cultivars to neighbours of varying genetic relatedness consisting of other commercial cultivars (intraspecific), its wild progenitor Glycine soja, and another leguminous species Phaseolus vulgaris (interspecific). We found, for the first time to our knowledge, that a commercial soya bean cultivar, OAC Wallace, showed identity recognition responses to neighbours at different levels of genetic relatedness. OAC Wallace showed no response when grown with other commercial soya bean cultivars (intra-specific neighbours), showed increased allocation to leaves compared with stems with wild soya beans (highly related wild progenitor species), and increased allocation to leaves compared with stems and roots with white beans (interspecific neighbours). Wild soya bean also responded to identity recognition but these responses involved changes in biomass allocation towards stems instead of leaves suggesting that identity recognition responses are species-specific and consistent with the ecology of the species. In conclusion, elucidating identity recognition in crops may provide further knowledge into mechanisms of crop competition and the relationship between crop density and yield.}, } @article {pmid28233388, year = {2017}, author = {Erb, WM and Porter, LM}, title = {Mother's little helpers: What we know (and don't know) about cooperative infant care in callitrichines.}, journal = {Evolutionary anthropology}, volume = {26}, number = {1}, pages = {25-37}, doi = {10.1002/evan.21516}, pmid = {28233388}, issn = {1520-6505}, mesh = {Animals ; Anthropology, Physical ; *Biological Evolution ; Callitrichinae/*physiology ; *Cooperative Behavior ; Female ; Male ; *Maternal Behavior ; Selection, Genetic ; }, abstract = {Since Darwin (), scientists have been puzzled by how behaviors that impose fitness costs on helpers while benefiting their competitors could evolve through natural selection. Hamilton's () theory of inclusive fitness provided an explanation by showing how cooperative behaviors could be adaptive if directed at closely related kin. Recent studies, however, have begun to question whether kin selection is sufficient to explain cooperative behavior in some species (Bergmüller, Johnstone, Russell, & Bshary,). Many researchers have instead emphasized the importance of direct fitness benefits for helpers in the evolution of cooperative breeding systems. Furthermore, individuals can vary in who, when, and how much they help, and the factors that affect this variation are poorly understood (Cockburn, ; Heinsohn,). Cooperative breeders thus provide excellent models for the study of evolutionary theories of cooperation and conflict (Cant,).}, } @article {pmid28229624, year = {2017}, author = {Gray, PB and Brogdon, E}, title = {Do Step- and Biological Grandparents Show Differences in Investment and Emotional Closeness With Their Grandchildren?.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {15}, number = {1}, pages = {1474704917694367}, pmid = {28229624}, issn = {1474-7049}, mesh = {Adult ; Female ; Grandparents/*psychology ; Humans ; *Intergenerational Relations ; Male ; }, abstract = {Human children are raised by a variety of caregivers including grandparents. A few studies have assessed potential differences in direct caregiving, financial expenditures, and emotional closeness between biological and step-grandparents. Drawing upon kin selection theory, we hypothesized that step-grandparents would provide less care and be less emotionally close to grandchildren than would biological grandparents. A sample of 341 heterosexual U.S. adults 25-35 years of age in a long-term partnership and with a biological child 5 years of age or younger were recruited via Amazon Mechanical Turk. Subjects provided sociodemographic information and answered questions about the dynamics between their own parent/stepparent and their own youngest biological child (hence, biological/step-grandparenting dynamics). Main analyses were restricted to within-subject comparisons. Results showed that biological grandmothers provided more direct childcare, financial expenditures, and had more emotionally close relationships with grandchildren than did step-grandmothers. Biological grandfathers provided less direct care and had less emotionally close relationships than step-grandfathers but did not exhibit differences in financial expenditures. Biological grandmothers provided more direct care, financial investment, and were more emotionally close to the referential grandchild than were biological grandfathers. Step-grandfathers were more emotionally close and more often played with grandchildren than step-grandmothers. These findings partially support kin selection theory. We discuss the relevance of factors such as competing demands on grandmothers' investment in biological and step-grandchildren and grandfathering serving in part as mating effort. Sex differences in biological grandparenting also mirror those in parenting. We suggest directions for future research, including on grandfathers, particularly in patrilineal societies.}, } @article {pmid28202814, year = {2017}, author = {Vedder, O and Zhang, H and Bouwhuis, S}, title = {Early mortality saves energy: estimating the energetic cost of excess offspring in a seabird.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1849}, pages = {}, pmid = {28202814}, issn = {1471-2954}, mesh = {Animals ; Charadriiformes/*metabolism ; *Clutch Size ; Energy Intake ; *Mortality ; }, abstract = {Offspring are often produced in excess as insurance against stochastic events or unpredictable resources. This strategy may result in high early-life mortality, yet age-specific mortality before offspring independence and its associated costs have rarely been quantified. In this study, we modelled age-specific survival from hatching to fledging using 24 years of data on hatching order (HO), growth and age of mortality of more than 15 000 common tern (Sterna hirundo) chicks. We found that mortality peaked directly after hatching, after which it declined rapidly. Mortality hazard was best described with the Gompertz function, and was higher with later HO, mainly due to differences in baseline mortality hazard, rather than age-dependent mortality. Based on allometric mass-metabolism relationships and detailed growth curves of starving chicks, we estimated that the average metabolizable energy intake of non-fledged chicks was only 8.7% of the metabolizable energy intake of successful chicks during the nestling phase. Although 54% of hatchlings did not fledge, our estimates suggest them to have consumed only 9.3% of the total energy consumption of all hatched chicks in the population before fledging. We suggest that rapid mortality of excess offspring is part of an adaptive brood reduction strategy to the benefit of the parents.}, } @article {pmid28107054, year = {2017}, author = {Andersson, M}, title = {Helping Relatives Survive and Reproduce: Inclusive Fitness and Reproductive Value in Brood Parasitism.}, journal = {The American naturalist}, volume = {189}, number = {2}, pages = {138-152}, doi = {10.1086/689991}, pmid = {28107054}, issn = {1537-5323}, mesh = {Animals ; Birds ; Female ; *Host-Parasite Interactions ; *Nesting Behavior ; *Reproduction ; Symbiosis ; }, abstract = {Costly help can raise a relative's reproduction, survival, and reproductive value and increase the inclusive fitness of the donor of help. Donor fitness is explored here in conspecific brood parasitism. In this alternative reproductive tactic, some females, "parasites," lay eggs in nests of other females of the same species, "hosts," suppliers of help that alone take care of the offspring. Modeling shows that hosts can gain inclusive fitness if parasitized by relatives whose reproduction or survival is thereby increased. These predictions are explored in waterfowl with frequent brood parasitism, female-biased philopatry, and neighbor relatedness. Approximate estimates based on waterfowl reproductive and life-history data show that host inclusive-fitness gain is often possible with related parasites. The largest gains can be achieved through increased reproduction, but gain is also possible through higher survival of parasites that avoid increased predation and other risks of nesting. Inclusive fitness depends on parasite reproductive value and can be highest for a host parasitized by her mother and for old, senescent hosts with low fecundity, helping young related parasites. These results and observed levels of host-parasite relatedness suggest that being "parasitized" in waterfowl is sometimes neutral or even advantageous because of inclusive-fitness benefits, contributing to evolution of frequent conspecific brood parasitism in this group.}, } @article {pmid28089514, year = {2017}, author = {Croft, DP and Johnstone, RA and Ellis, S and Nattrass, S and Franks, DW and Brent, LJ and Mazzi, S and Balcomb, KC and Ford, JK and Cant, MA}, title = {Reproductive Conflict and the Evolution of Menopause in Killer Whales.}, journal = {Current biology : CB}, volume = {27}, number = {2}, pages = {298-304}, doi = {10.1016/j.cub.2016.12.015}, pmid = {28089514}, issn = {1879-0445}, mesh = {Animals ; *Biological Evolution ; Female ; *Menopause ; Reproduction ; Whale, Killer/*physiology ; }, abstract = {Why females of some species cease ovulation prior to the end of their natural lifespan is a long-standing evolutionary puzzle [1-4]. The fitness benefits of post-reproductive helping could in principle select for menopause [1, 2, 5], but the magnitude of these benefits appears insufficient to explain the timing of menopause [6-8]. Recent theory suggests that the cost of inter-generational reproductive conflict between younger and older females of the same social unit is a critical missing term in classical inclusive fitness calculations (the "reproductive conflict hypothesis" [6, 9]). Using a unique long-term dataset on wild resident killer whales, where females can live decades after their final parturition, we provide the first test of this hypothesis in a non-human animal. First, we confirm previous theoretical predictions that local relatedness increases with female age up to the end of reproduction. Second, we construct a new evolutionary model and show that given these kinship dynamics, selection will favor younger females that invest more in competition, and thus have greater reproductive success, than older females (their mothers) when breeding at the same time. Third, we test this prediction using 43 years of individual-based demographic data in resident killer whales and show that when mothers and daughters co-breed, the mortality hazard of calves from older-generation females is 1.7 times that of calves from younger-generation females. Intergenerational conflict combined with the known benefits conveyed to kin by post-reproductive females can explain why killer whales have evolved the longest post-reproductive lifespan of all non-human animals.}, } @article {pmid28079112, year = {2017}, author = {Lewin-Epstein, O and Aharonov, R and Hadany, L}, title = {Microbes can help explain the evolution of host altruism.}, journal = {Nature communications}, volume = {8}, number = {}, pages = {14040}, pmid = {28079112}, issn = {2041-1723}, mesh = {*Altruism ; *Biological Evolution ; *Microbiota ; *Models, Genetic ; }, abstract = {The evolution of altruistic behaviour, which is costly to the donor but beneficial for the recipient, is among the most intriguing questions in evolutionary biology. Several theories have been proposed to explain it, including kin selection, group selection and reciprocity. Here we propose that microbes that manipulate their hosts to act altruistically could be favoured by selection, and may play a role in the widespread occurrence of altruism. Using computational models, we find that microbe-induced altruism can explain the evolution of host altruistic behaviour under wider conditions than host-centred theories, including in a fully mixed host population, without repeating interactions or individual recognition. Our results suggest that factors such as antibiotics that kill microbes might negatively affect cooperation in a wide range of organisms.}, } @article {pmid28066387, year = {2016}, author = {Zhang, Z and Claessen, D and Rozen, DE}, title = {Understanding Microbial Divisions of Labor.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {2070}, pmid = {28066387}, issn = {1664-302X}, abstract = {Divisions of labor are ubiquitous in nature and can be found at nearly every level of biological organization, from the individuals of a shared society to the cells of a single multicellular organism. Many different types of microbes have also evolved a division of labor among its colony members. Here we review several examples of microbial divisions of labor, including cases from both multicellular and unicellular microbes. We first discuss evolutionary arguments, derived from kin selection, that allow divisions of labor to be maintained in the face of non-cooperative cheater cells. Next we examine the widespread natural variation within species in their expression of divisions of labor and compare this to the idea of optimal caste ratios in social insects. We highlight gaps in our understanding of microbial caste ratios and argue for a shift in emphasis from understanding the maintenance of divisions of labor, generally, to instead focusing on its specific ecological benefits for microbial genotypes and colonies. Thus, in addition to the canonical divisions of labor between, e.g., reproductive and vegetative tasks, we may also anticipate divisions of labor to evolve to reduce the costly production of secondary metabolites or secreted enzymes, ideas we consider in the context of streptomycetes. The study of microbial divisions of labor offers opportunities for new experimental and molecular insights across both well-studied and novel model systems.}, } @article {pmid28057829, year = {2017}, author = {Matsuura, K}, title = {Evolution of the asexual queen succession system and its underlying mechanisms in termites.}, journal = {The Journal of experimental biology}, volume = {220}, number = {Pt 1}, pages = {63-72}, doi = {10.1242/jeb.142547}, pmid = {28057829}, issn = {1477-9145}, mesh = {Animals ; *Biological Evolution ; Female ; Genomic Imprinting ; Isoptera/genetics/*physiology ; Male ; Parthenogenesis ; Pheromones/metabolism ; Reproduction ; *Reproduction, Asexual ; Sex Ratio ; Sexual Behavior, Animal ; }, abstract = {One major advantage of sexual reproduction over asexual reproduction is its promotion of genetic variation, although it reduces the genetic contribution to offspring. Queens of social insects double their contribution to the gene pool, while overuse of asexual reproduction may reduce the ability of the colony to adapt to environmental stress because of the loss of genetic diversity. Recent studies have revealed that queens of some termite species can solve this tradeoff by using parthenogenesis to produce the next generation of queens and sexual reproduction to produce other colony members. This reproductive system, known as asexual queen succession (AQS), has been identified in the subterranean termites Reticulitermes speratus, Reticulitermes virginicus and Reticulitermes lucifugus and in the Neotropical higher termites Embiratermes neotenicus and Cavitermes tuberosus The studies presented here have uncovered the unusual modes of reproduction in termites and have aimed to identify their underlying mechanisms. The study of AQS, the mixed use of sexual and asexual reproduction, is of fundamental importance as it may provide a key to solve the evolutionary paradox of sex.}, } @article {pmid31572069, year = {2017}, author = {Graves, CJ and Weinreich, DM}, title = {Variability in fitness effects can preclude selection of the fittest.}, journal = {Annual review of ecology, evolution, and systematics}, volume = {48}, number = {1}, pages = {399-417}, pmid = {31572069}, issn = {1543-592X}, support = {R01 GM095728/GM/NIGMS NIH HHS/United States ; }, abstract = {Evolutionary biologists often predict the outcome of natural selection on an allele by measuring its effects on lifetime survival and reproduction of individual carriers. However, alleles affecting traits like sex, evolvability, and cooperation can cause fitness effects that depend heavily on differences in the environmental, social, and genetic context of individuals carrying the allele. This variability makes it difficult to summarize the evolutionary fate of an allele based solely on its effects on any one individual. Attempts to average over this variability can sometimes salvage the concept of fitness. In other cases evolutionary outcomes can only be predicted by considering the entire genealogy of an allele, thus limiting the utility of individual fitness altogether. We describe a number of intriguing new evolutionary phenomena that have emerged in studies that explicitly model long-term lineage dynamics and discuss implications for the evolution of infectious diseases.}, } @article {pmid28035273, year = {2016}, author = {Procter, DS and Cottrell, JE and Watts, K and A'Hara, SW and Hofreiter, M and Robinson, EJ}, title = {Does cooperation mean kinship between spatially discrete ant nests?.}, journal = {Ecology and evolution}, volume = {6}, number = {24}, pages = {8846-8856}, pmid = {28035273}, issn = {2045-7758}, abstract = {Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.}, } @article {pmid28028377, year = {2016}, author = {Preston, SA and Briskie, JV and Hatchwell, BJ}, title = {Adult helpers increase the recruitment of closely related offspring in the cooperatively breeding rifleman.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {27}, number = {6}, pages = {1617-1626}, pmid = {28028377}, issn = {1045-2249}, abstract = {Indirect fitness benefits gained through kin-selected helping are widely invoked to explain the evolution of cooperative breeding behavior in birds. However, the impact of helpers on productivity of helped broods can be difficult to determine if the effects are confounded by territory quality or if the benefit of helpers is apparent only in the long term. In riflemen Acanthisitta chloris, helping and group membership are effectively decoupled as adult helpers are individuals that have dispersed from their natal territory and live independently from breeders in "kin neighborhoods." Nevertheless, helpers direct their care toward close relatives, suggesting that helping provides indirect fitness benefits. The aim of this study was to examine the benefits of helpers to recipient offspring in the rifleman, investigating both short- and long-term effects. The total amount of food delivered to nestlings in helped broods was greater than that received by broods without helpers. This did not result in any short-term increase in nestling mass or nestling body condition nor was there any reduction in length of the nestling period at helped nests. However, helpers were associated with a significant increase in juvenile recruitment, with twice the proportion of fledglings surviving to the next breeding season from helped broods relative to unhelped broods. Thus, helpers gain indirect fitness by improving the survival of kin, and in contrast to a previous study of riflemen, we conclude that kin selection has played a key role in the evolution of cooperative breeding in this species.}, } @article {pmid28018027, year = {2017}, author = {Widdig, A and Muniz, L and Minkner, M and Barth, Y and Bley, S and Ruiz-Lambides, A and Junge, O and Mundry, R and Kulik, L}, title = {Low incidence of inbreeding in a long-lived primate population isolated for 75 years.}, journal = {Behavioral ecology and sociobiology}, volume = {71}, number = {1}, pages = {18}, pmid = {28018027}, issn = {0340-5443}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {ABSTRACT: When close relatives mate, offspring are expected to suffer fitness consequences due to inbreeding depression. Inbreeding has previously been quantified in two ways: using a sufficiently large panel of markers or deep and complete pedigrees over several generations. However, the application of both approaches is still limited by the challenge of compiling such data for species with long generation times, such as primates. Here, we assess inbreeding in rhesus macaques living on Cayo Santiago (Puerto Rico), a population genetically isolated since 1938, but descendant of a large set of presumably unrelated founders. Using comprehensive genetic data, we calculated inbreeding coefficients (F) for 2669 individuals with complete three generation pedigrees and 609 individuals with complete four generation pedigrees. We found that 0.79 and 7.39% of individuals had an F > 0 when using data from three and four generation pedigrees, respectively. No evidence of an increase in inbreeding over the study period (up to 23 years) was found. Furthermore, the observed mean relatedness of breeding pairs differed significantly from the distribution of parental relatedness expected as simulated based on previous reproductive data, suggesting that kin generally avoid breeding with each other. Finally, inbreeding was not a predictor of early mortality measured as survival until weaning and sexual maturation, respectively. Our results remain consistent with three estimators of inbreeding (standardized heterozygosity, internal relatedness, and homozygosity by loci) using up to 42 highly polymorphic microsatellites for the same set of individuals. Together, our results demonstrate that close inbreeding may not be prevalent even in populations isolated over long periods when mechanisms of inbreeding avoidance can operate.

SIGNIFICANCE STATEMENT: When close relatives mate, offspring may suffer from such inbreeding, e.g., via lower survival and/or fertility. Using (i) a large panel of genetic markers and (ii) complete three or four generation pedigrees, respectively, we show that incidences of inbreeding in a long-lived primate population are rare, even after genetic isolation for 75 years. Moreover, our simulations suggest that kin in our population generally avoid breeding with each other. Finally, the few inbred individuals detected in our large sample did not suffer from lower survival. Given that many animal species face dramatic habitat loss combined with critical population declines, our study provides important implications for conservation biology in general and for population management in particular.}, } @article {pmid28012185, year = {2017}, author = {Taylor, P}, title = {Inclusive fitness in finite populations-effects of heterogeneity and synergy.}, journal = {Evolution; international journal of organic evolution}, volume = {71}, number = {3}, pages = {508-525}, doi = {10.1111/evo.13160}, pmid = {28012185}, issn = {1558-5646}, mesh = {Game Theory ; *Gene Frequency ; *Genetic Fitness ; Models, Genetic ; Population Density ; *Selection, Genetic ; }, abstract = {I review recent results concerning the relationship between the inclusive fitness (IF) effect and standard measures of allele fitness in a finite-population, with attention to the effect of heterogeneity in population structure and nonadditive fitness effects. In both cases, existing theoretical work is somewhat technical and I try to provide a more transparent account. In a heterogeneous population it is known that inclusive fitness will generally fail to incorporate the effects of selection on the distribution of alleles among states unless a reproductive-value weighting is used. But even given that, recent work shows that under certain updating rules, the IF effect can fail to be equivalent to standard measures such as fixation probability. In terms of synergistic fitness effects, I review the result that in the finite population model, the IF effect can be calculated using only "additive" relatedness coefficients so that computational difficulties found in the infinite-population model do not arise. In my own work, there is an interaction here in that my 2012 work on synergy with Maciejewski made an assumption about inclusive fitness that my 2014 work on heterogeneity with Tarnita showed to be wrong. I include (Appendix C) a corrected argument for the 2012 result.}, } @article {pmid27991659, year = {2017}, author = {Faria, GS and Varela, SA and Gardner, A}, title = {Sexual selection modulates genetic conflicts and patterns of genomic imprinting.}, journal = {Evolution; international journal of organic evolution}, volume = {71}, number = {3}, pages = {526-540}, pmid = {27991659}, issn = {1558-5646}, mesh = {Alleles ; *Animal Distribution ; Animals ; Female ; *Genetic Fitness ; *Genomic Imprinting ; Invertebrates/*genetics/physiology ; Male ; Models, Genetic ; Population Density ; Selection, Genetic ; Sex Factors ; Vertebrates/*genetics/physiology ; }, abstract = {Recent years have seen a surge of interest in linking the theories of kin selection and sexual selection. In particular, there is a growing appreciation that kin selection, arising through demographic factors such as sex-biased dispersal, may modulate sexual conflicts, including in the context of male-female arms races characterized by coevolutionary cycles. However, evolutionary conflicts of interest need not only occur between individuals, but may also occur within individuals, and sex-specific demography is known to foment such intragenomic conflict in relation to social behavior. Whether and how this logic holds in the context of sexual conflict-and, in particular, in relation to coevolutionary cycles-remains obscure. We develop a kin-selection model to investigate the interests of different genes involved in sexual and intragenomic conflict, and we show that consideration of these conflicting interests yields novel predictions concerning parent-of-origin specific patterns of gene expression and the detrimental effects of different classes of mutation and epimutation at loci underpinning sexually selected phenotypes.}, } @article {pmid27990255, year = {2016}, author = {Newman, SJ and Eyre, S and Kimble, CH and Arcos-Burgos, M and Hogg, C and Easteal, S}, title = {Reproductive success is predicted by social dynamics and kinship in managed animal populations.}, journal = {F1000Research}, volume = {5}, number = {}, pages = {870}, pmid = {27990255}, issn = {2046-1402}, abstract = {Kin and group interactions are important determinants of reproductive success in many species. Their optimization could, therefore, potentially improve the productivity and breeding success of managed populations used for agricultural and conservation purposes. Here we demonstrate this potential using a novel approach to measure and predict the effect of kin and group dynamics on reproductive output in a well-known species, the meerkat Suricata suricatta. Variation in social dynamics predicts 30% of the individual variation in reproductive success of this species in managed populations, and accurately forecasts reproductive output at least two years into the future. Optimization of social dynamics in captive meerkat populations doubles their projected reproductive output. These results demonstrate the utility of a quantitative approach to breeding programs informed by social and kinship dynamics. They suggest that this approach has great potential for improvements in the management of social endangered and agricultural species.}, } @article {pmid27987088, year = {2017}, author = {VanderLaan, DP and Petterson, LJ and Vasey, PL}, title = {Elevated Kin-Directed Altruism Emerges in Childhood and Is Linked to Feminine Gender Expression in Samoan Fa'afafine: A Retrospective Study.}, journal = {Archives of sexual behavior}, volume = {46}, number = {1}, pages = {95-108}, doi = {10.1007/s10508-016-0884-2}, pmid = {27987088}, issn = {1573-2800}, mesh = {Adult ; *Altruism ; Female ; Gender Identity ; Homosexuality, Male/*ethnology ; Humans ; Male ; Reproduction ; Retrospective Studies ; Samoa ; Sexual Behavior/*ethnology ; Siblings ; }, abstract = {Androphilia refers to sexual attraction toward adult males, whereas gynephilia refers to sexual attraction toward adult females. The kin selection hypothesis posits that androphilic males help kin increase their reproductive output via kin-directed altruism, thus offsetting their own lowered reproduction and contributing to the fitness of genes underpinning male androphilia. Support for this hypothesis has been garnered in several Samoan studies showing that feminine androphilic males (known locally as fa'afafine) report elevated willingness to invest in nieces and nephews in adulthood. Also, recalled childhood kin attachment and concern for kin's well-being are elevated among Canadian androphilic males (i.e., gay men) and positively associated with childhood feminine gender expression. This study examined whether these childhood patterns were cross-culturally consistent and associated with adulthood kin-directed altruism in a Samoan sample. Samoan gynephilic men, androphilic women, and fa'afafine (N = 470) completed measures of recalled childhood kin attachment and concern for the well-being of kin, recalled childhood gender expression, and willingness in adulthood to invest in nieces and nephews. Fa'afafine recalled elevated anxiety due to separation from kin relative to men and elevated concern for kin's well-being relative to both men and women. Within groups, these characteristics were most robustly associated with childhood feminine gender expression and willingness in adulthood to invest in nieces and nephews among fa'afafine. These findings are consistent with the kin selection hypothesis and the adaptive feminine phenotype model, which proposes that a disposition toward elevated kin-directed altruism among androphilic males is associated with feminine gender expression.}, } @article {pmid27951454, year = {2017}, author = {Allen-Hermanson, S}, title = {Kamikazes and cultural evolution.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {61}, number = {}, pages = {11-19}, doi = {10.1016/j.shpsc.2016.12.001}, pmid = {27951454}, issn = {1879-2499}, mesh = {*Altruism ; Biological Evolution ; *Cultural Evolution ; Humans ; Japan ; Selection, Genetic ; *Warfare ; }, abstract = {Is cultural evolution needed to explain altruistic selfsacrifice? Some contend that cultural traits (e.g. beliefs, behaviors, and for some "memes") replicate according to selection processes that have "floated free" from biology. One test case is the example of suicide kamikaze attacks in wartime Japan. Standard biological mechanisms-such as reciprocal altruism and kin selection-might not seem to apply here: The suicide pilots did not act on the expectation that others would reciprocate, and they were supposedly sacrificing themselves for country and emperor, not close relatives. Yet an examination of both the historical record and the demands of evolutionary theory suggest the kamikaze phenomenon does not cry out for explanation in terms of a special non-biological selection process. This weakens the case for cultural evolution, and has interesting implications for our understanding of altruistic self-sacrifice.}, } @article {pmid27925168, year = {2017}, author = {Tan, CK and Doyle, P and Bagshaw, E and Richardson, DS and Wigby, S and Pizzari, T}, title = {The contrasting role of male relatedness in different mechanisms of sexual selection in red junglefowl.}, journal = {Evolution; international journal of organic evolution}, volume = {71}, number = {2}, pages = {403-420}, pmid = {27925168}, issn = {1558-5646}, support = {BB/K014544/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Chickens/genetics/*physiology ; Competitive Behavior ; Copulation ; Female ; Male ; *Mating Preference, Animal ; Spermatozoa/*physiology ; }, abstract = {In structured populations, competition for reproductive opportunities should be relaxed among related males. The few tests of this prediction often neglect the fact that sexual selection acts through multiple mechanisms, both before and after mating. We performed experiments to study the role of within-group male relatedness across pre- and postcopulatory mechanisms of sexual selection in social groups of red junglefowl, Gallus gallus, in which two related males and one unrelated male competed over females unrelated to all the males. We confirm theoretical expectations that, after controlling for male social status, competition over mating was reduced among related males. However, this effect was contrasted by other sexual selection mechanisms. First, females biased male mating in favor of the unrelated male, and might also favor his inseminations after mating. Second, males invested more-rather than fewer-sperm in postcopulatory competition with relatives. A number of factors may contribute to explain this counterintuitive pattern of sperm allocation, including trade-offs between male investment in pre- versus postcopulatory competition, differences in the relative relatedness of pre- versus postcopulatory competitors, and female bias in sperm utilization in response to male relatedness. Collectively, these results reveal that within-group male relatedness may have contrasting effects in different mechanisms of sexual selection.}, } @article {pmid27910006, year = {2016}, author = {Coco, E}, title = {William D. Hamilton's Brazilian lectures and his unpublished model regarding Wynne-Edwards's idea of natural selection. With a note on 'pluralism' and different philosophical approaches to evolution.}, journal = {History and philosophy of the life sciences}, volume = {38}, number = {4}, pages = {24}, doi = {10.1007/s40656-016-0125-y}, pmid = {27910006}, issn = {0391-9714}, mesh = {Animals ; *Biological Evolution ; Brazil ; England ; *Genetic Variation ; Genetics, Population/*history ; History, 20th Century ; Manuscripts as Topic ; *Selection, Genetic ; *Social Behavior ; }, abstract = {In 1975, the English evolutionist William Donald Hamilton (1936-2000) held in Brazil a series of lectures entitled "Population genetics and social behaviour". The unpublished notes of these conferences-written by Hamilton and recently discovered at the British Library-offer an opportunity to reflect on some of the author's ideas about evolution. The year of the conference is particularly significant, as it took place shortly after the applications of the Price equation with which Hamilton was able to build a model that included several levels of selection. In this paper I mainly analyse the inaugural lecture in which Hamilton proposes a simple model to disprove the hypothesis supported by the British zoologist C. Vero Wynne-Edwards (1906-1997) regarding mechanisms to prevent "over-exploitation of the food supply" in "the interests of the survival of the group". The document presented here is of great historical interest. Not only because manuscript offers a model that-since it was intended for teaching purposes-had never before appeared in the published version, but also because of the general index of the lectures that accompanies it. The latter allows us to make some hypothetical considerations on the relationship and differences between kin-selection, group-selection and inclusive fitness that Hamilton wanted to present to the attentive, well-prepared audience of the foreign university that had invited him.}, } @article {pmid27881747, year = {2016}, author = {Duthie, AB and Lee, AM and Reid, JM}, title = {Inbreeding parents should invest more resources in fewer offspring.}, journal = {Proceedings. Biological sciences}, volume = {283}, number = {1843}, pages = {}, pmid = {27881747}, issn = {1471-2954}, mesh = {Animals ; Female ; *Genetic Fitness ; *Inbreeding ; Male ; *Mating Preference, Animal ; Models, Genetic ; *Reproduction ; }, abstract = {Inbreeding increases parent-offspring relatedness and commonly reduces offspring viability, shaping selection on reproductive interactions involving relatives and associated parental investment (PI). Nevertheless, theories predicting selection for inbreeding versus inbreeding avoidance and selection for optimal PI have only been considered separately, precluding prediction of optimal PI and associated reproductive strategy given inbreeding. We unify inbreeding and PI theory, demonstrating that optimal PI increases when a female's inbreeding decreases the viability of her offspring. Inbreeding females should therefore produce fewer offspring due to the fundamental trade-off between offspring number and PI. Accordingly, selection for inbreeding versus inbreeding avoidance changes when females can adjust PI with the degree that they inbreed. By contrast, optimal PI does not depend on whether a focal female is herself inbred. However, inbreeding causes optimal PI to increase given strict monogamy and associated biparental investment compared with female-only investment. Our model implies that understanding evolutionary dynamics of inbreeding strategy, inbreeding depression, and PI requires joint consideration of the expression of each in relation to the other. Overall, we demonstrate that existing PI and inbreeding theories represent special cases of a more general theory, implying that intrinsic links between inbreeding and PI affect evolution of behaviour and intrafamilial conflict.}, } @article {pmid27859791, year = {2016}, author = {Schultner, E and Saramäki, J and Helanterä, H}, title = {Genetic structure of native ant supercolonies varies in space and time.}, journal = {Molecular ecology}, volume = {25}, number = {24}, pages = {6196-6213}, doi = {10.1111/mec.13912}, pmid = {27859791}, issn = {1365-294X}, mesh = {Animals ; Ants/*genetics ; Finland ; *Genetics, Population ; Social Behavior ; Spatio-Temporal Analysis ; }, abstract = {Ant supercolonies are the largest cooperative units known in nature. They consist of networks of interconnected nests with hundreds of reproductive queens, where individuals move freely between nests, cooperate across nest boundaries and show little aggression towards non-nestmates. The combination of high queen numbers and free mixing of workers, queens and brood between nests results in extremely low nestmate relatedness. In such low-relatedness societies, cooperative worker behaviour appears maladaptive because it may aid random individuals instead of relatives. Here, we provide a comprehensive picture of genetic substructure in supercolonies of the native wood ant Formica aquilonia using traditional population genetic as well as network analysis methods. Specifically, we test for spatial and temporal variation in genetic structure of different classes of individuals within supercolonies and analyse the role of worker movement in determining supercolony genetic networks. We find that relatedness within supercolonies is low but positive when viewed on a population level, which may be due to limited dispersal of individuals and/or ecological factors such as nest site limitation and competition against conspecifics. Genetic structure of supercolonies varied with both sample class and sampling time point, which indicates that mobility of individuals varies according to both caste and season and suggests that generalizing has to be carried out with caution in studies of supercolonial species. Overall, our analysis provides novel evidence that native wood ant supercolonies exhibit fine-scale genetic substructure, which may explain the maintenance of cooperation in these low-relatedness societies.}, } @article {pmid27852800, year = {2016}, author = {Bawa, KS}, title = {Kin selection and the evolution of plant reproductive traits.}, journal = {Proceedings. Biological sciences}, volume = {283}, number = {1842}, pages = {}, pmid = {27852800}, issn = {1471-2954}, mesh = {*Biological Evolution ; Flowers/genetics ; Phenotype ; *Plant Physiological Phenomena ; Plants/*genetics ; Pollen/genetics ; *Pollination ; Reproduction ; Seeds/*genetics ; }, abstract = {Competition among developing seeds and sibling rivalry within multiovulated ovaries can be deleterious for both the maternal parent and the siblings. Increased genetic relatedness of seeds within the ovary may foster kin selection and reduce the deleterious consequences of sibling competition. The pollen parent may also be selected for siring all progeny within a fruit. I propose a series of hypotheses to explain the evolution of a number of reproductive traits in angiosperms in the context of kin selection and sibling rivalry within the ovaries of angiosperms. I present evidence to show that a single-pollen parent, indeed, often sires seeds within multiovulated ovaries. Various types of pollen aggregations and transfer of such pollen masses to the stigmas of flowers by specialized pollinators make this increased genetic relatedness possible. An alternative mode to reduce sibling rivalry may be the reduction of ovule number to one, an evolutionary trend that has independently occurred many times in flowering plants. Finally, I build on previously established correlations to predict two sets of correlations among reproductive traits. In the first case, large showy flowers, transfer of pollen en masse by specialized pollinators, and multiovulated ovaries and multisided fruits seem to be correlated. In the second case, the previously established correlations among small and inconspicuous flowers, pollination by wind, water or generalist insects, flowers and fruits with few or single ovules and seeds, respectively, may also include monoecy or dioecy. Although correlations among many of these traits have been established in the past, I invoke kin selection and sibling competition to explain the evolution of correlated traits as two distinct evolutionary pathways in angiosperms.}, } @article {pmid27812427, year = {2016}, author = {Saberski, ET and Diamond, JD and Henneman, NF and Levitis, DA}, title = {Post-reproductive parthenogenetic pea aphids (Acyrthosiphon pisum) are visually identifiable and disproportionately positioned distally to clonal colonies.}, journal = {PeerJ}, volume = {4}, number = {}, pages = {e2631}, pmid = {27812427}, issn = {2167-8359}, support = {P20 GM103423/GM/NIGMS NIH HHS/United States ; }, abstract = {The role of kin-selection in the evolution of post-reproductive life is controversial. While anthropological and demographic studies strongly suggest that humans and a few other species experience kin selection for significant post-reproductive survival, these results are necessarily correlational. Understanding could therefore be advanced by the development of a globally available, field and laboratory tractable experimental model of kin-selected post-reproductive survival. In only one invertebrate (Quadrartus yoshinomiyai, a gall-forming aphid endemic to Japan) have individuals too old to reproduce been shown to be both numerous in natural habitats and able to help close relatives survive or reproduce. Pea aphids, (Acyrthosiphon pisum), common, tractable organisms, frequently outlive their reproductive ages in laboratories, live in tight interacting groups that are often clonal, and therefore should be evaluated as potential model organisms for the study of adaptive post-reproductive life. The first major step in this process is to identify an optimal method for assessing if a parthenogenetic adult is post-reproductive. We evaluated three methods, relying respectively on isolation in clip cages, visual examination for embryonic eyespots, and dissection. In every case each method identified the same individuals as reproductive versus post-reproductive. While the clip-cage method requires a multi-day wait to produce data, and dissection is inevitably fatal, the eyespot method is quick (under one minute per individual) easy, and non-invasive. This method makes it possible to accurately assess the post-reproductive status of a large number of parthenogenetic pea aphids. We demonstrate the usefulness of the eyespot method in showing that while reproductively valuable adults tend to place themselves near the centers of clonal colonies, less valuable post-reproductive adults are more often at or beyond the edges of colonies. These encouraging early results provide both impetuous and aid for further investigations into the post-reproductive lives of pea aphids.}, } @article {pmid27798295, year = {2016}, author = {Lion, S and Gandon, S}, title = {Spatial evolutionary epidemiology of spreading epidemics.}, journal = {Proceedings. Biological sciences}, volume = {283}, number = {1841}, pages = {}, pmid = {27798295}, issn = {1471-2954}, mesh = {Animals ; *Biological Evolution ; Epidemics ; *Host-Parasite Interactions ; *Models, Biological ; Parasites ; Parasitic Diseases/*epidemiology ; Spatial Analysis ; Virulence ; }, abstract = {Most spatial models of host-parasite interactions either neglect the possibility of pathogen evolution or consider that this process is slow enough for epidemiological dynamics to reach an equilibrium on a fast timescale. Here, we propose a novel approach to jointly model the epidemiological and evolutionary dynamics of spatially structured host and pathogen populations. Starting from a multi-strain epidemiological model, we use a combination of spatial moment equations and quantitative genetics to analyse the dynamics of mean transmission and virulence in the population. A key insight of our approach is that, even in the absence of long-term evolutionary consequences, spatial structure can affect the short-term evolution of pathogens because of the build-up of spatial differentiation in mean virulence. We show that spatial differentiation is driven by a balance between epidemiological and genetic effects, and this quantity is related to the effect of kin competition discussed in previous studies of parasite evolution in spatially structured host populations. Our analysis can be used to understand and predict the transient evolutionary dynamics of pathogens and the emergence of spatial patterns of phenotypic variation.}, } @article {pmid27786267, year = {2016}, author = {Camiletti, AL and Percival-Smith, A and Croft, JR and Thompson, GJ}, title = {A novel screen for genes associated with pheromone-induced sterility.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {36041}, pmid = {27786267}, issn = {2045-2322}, mesh = {Animals ; Drosophila/*genetics/*physiology ; Fertility ; *Genes, Insect ; Genetic Testing/*methods ; Infertility ; Pheromones/*metabolism ; Sexual Behavior, Animal ; Smell ; }, abstract = {For honey bee and other social insect colonies the 'queen substance' regulates colony reproduction rendering workers functionally sterile. The evolution of worker reproductive altruism is explained by inclusive fitness theory, but little is known of the genes involved or how they regulate the phenotypic expression of altruism. We previously showed that application of honeybee queen pheromone to virgin fruit flies suppresses fecundity. Here we exploit this finding to identify genes associated with the perception of an ovary-inhibiting social pheromone. Mutational and RNAi approaches in Drosophila reveal that the olfactory co-factor Orco together with receptors Or49b, Or56a and Or98a are potentially involved in the perception of queen pheromone and the suppression of fecundity. One of these, Or98a, is known to mediate female fly mating behaviour, and its predicted ligand is structurally similar to a methyl component of the queen pheromone. Our novel approach to finding genes associated with pheromone-induced sterility implies conserved reproductive regulation between social and pre-social orders, and further helps to identify candidate orthologues from the pheromone-responsive pathway that may regulate honeybee worker sterility.}, } @article {pmid27775099, year = {2016}, author = {Zhang, BY and Fan, SJ and Li, C and Zheng, XD and Bao, JZ and Cressman, R and Tao, Y}, title = {Opting out against defection leads to stable coexistence with cooperation.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {35902}, pmid = {27775099}, issn = {2045-2322}, abstract = {Cooperation coexisting with defection is a common phenomenon in nature and human society. Previous studies for promoting cooperation based on kin selection, direct and indirect reciprocity, graph selection and group selection have provided conditions that cooperators outcompete defectors. However, a simple mechanism of the long-term stable coexistence of cooperation and defection is still lacking. To reveal the effect of direct reciprocity on the coexistence of cooperation and defection, we conducted a simple experiment based on the Prisoner's Dilemma (PD) game, where the basic idea behind our experiment is that all players in a PD game should prefer a cooperator as an opponent. Our experimental and theoretical results show clearly that the strategies allowing opting out against defection are able to maintain this stable coexistence.}, } @article {pmid27723824, year = {2016}, author = {Beck, CM and Willett, JL and Cunningham, DA and Kim, JJ and Low, DA and Hayes, CS}, title = {CdiA Effectors from Uropathogenic Escherichia coli Use Heterotrimeric Osmoporins as Receptors to Recognize Target Bacteria.}, journal = {PLoS pathogens}, volume = {12}, number = {10}, pages = {e1005925}, pmid = {27723824}, issn = {1553-7374}, support = {R01 GM117930/GM/NIGMS NIH HHS/United States ; }, mesh = {Contact Inhibition/physiology ; Escherichia coli Proteins/*metabolism ; Flow Cytometry ; Immunoblotting ; Membrane Proteins/*metabolism ; Porins/*metabolism ; Uropathogenic Escherichia coli/*metabolism ; }, abstract = {Many Gram-negative bacterial pathogens express contact-dependent growth inhibition (CDI) systems that promote cell-cell interaction. CDI+ bacteria express surface CdiA effector proteins, which transfer their C-terminal toxin domains into susceptible target cells upon binding to specific receptors. CDI+ cells also produce immunity proteins that neutralize the toxin domains delivered from neighboring siblings. Here, we show that CdiAEC536 from uropathogenic Escherichia coli 536 (EC536) uses OmpC and OmpF as receptors to recognize target bacteria. E. coli mutants lacking either ompF or ompC are resistant to CDIEC536-mediated growth inhibition, and both porins are required for target-cell adhesion to inhibitors that express CdiAEC536. Experiments with single-chain OmpF fusions indicate that the CdiAEC536 receptor is heterotrimeric OmpC-OmpF. Because the OmpC and OmpF porins are under selective pressure from bacteriophages and host immune systems, their surface-exposed loops vary between E. coli isolates. OmpC polymorphism has a significant impact on CDIEC536 mediated competition, with many E. coli isolates expressing alleles that are not recognized by CdiAEC536. Analyses of recombinant OmpC chimeras suggest that extracellular loops L4 and L5 are important recognition epitopes for CdiAEC536. Loops L4 and L5 also account for much of the sequence variability between E. coli OmpC proteins, raising the possibility that CDI contributes to the selective pressure driving OmpC diversification. We find that the most efficient CdiAEC536 receptors are encoded by isolates that carry the same cdi gene cluster as E. coli 536. Thus, it appears that CdiA effectors often bind preferentially to "self" receptors, thereby promoting interactions between sibling cells. As a consequence, these effector proteins cannot recognize nor suppress the growth of many potential competitors. These findings suggest that self-recognition and kin selection are important functions of CDI.}, } @article {pmid27720058, year = {2016}, author = {Séguret, A and Bernadou, A and Paxton, RJ}, title = {Facultative social insects can provide insights into the reversal of the longevity/fecundity trade-off across the eusocial insects.}, journal = {Current opinion in insect science}, volume = {16}, number = {}, pages = {95-103}, doi = {10.1016/j.cois.2016.06.001}, pmid = {27720058}, issn = {2214-5753}, mesh = {Animals ; *Biological Evolution ; Insecta/*physiology ; Longevity/*physiology ; Reproduction/physiology ; Selection, Genetic ; Social Behavior ; }, abstract = {In eusocial insects, reversal of the fecundity/longevity trade-off and extreme differences in life histories between castes of the same species garner scientific and public interest. Facultative social species at the threshold of sociality, in which individuals are socially plastic, provide an excellent opportunity to understand the causes and mechanisms underlying this reversal in life history trade-off associated with eusociality. We briefly present the ultimate factors favoring sociality and the association between fecundity and longevity in facultative eusocial insects, including kin selection and disposable soma, as well as proximate mechanisms observed in such species, such as differences in hormone titers and functions. Potential genetic underpinnings of lifespan and fecundity differences between castes are discussed and future research directions are proposed.}, } @article {pmid27656086, year = {2016}, author = {Walker, LA and York, JE and Young, AJ}, title = {Sexually selected sentinels? Evidence of a role for intrasexual competition in sentinel behavior.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {27}, number = {5}, pages = {1461-1470}, pmid = {27656086}, issn = {1045-2249}, support = {BB/H022716/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Although the evolutionary mechanisms that favor investment in cooperative behaviors have long been a focus of research, comparatively few studies have considered the role that sexual selection may play. For example, evolutionary explanations for sentinel behavior (where 1 individual assumes an elevated position and scans the surroundings while other group members forage nearby) have traditionally focused on the inclusive fitness benefits arising from its effects on predation risk, while its potential role in defense against intrasexual competitors remains largely unexplored. Here, we provide experimental evidence of a role for sentinel behavior in intrasexual competition, in a cooperatively breeding songbird, the white-browed sparrow weaver (Plocepasser mahali). First, dominant males sentinel substantially more than other group members (even when controlling for variation in age and body condition), consistent with a role for sentineling in intrasexual competition for mates and/or territory. Second, experimental playback of an unfamiliar male's solo song elicited a marked increase in sentineling by the dominant male, and the vocal response to the playback also positively predicted his sentinel effort following the simulated intrusion. A second experiment also suggests that sentineling may facilitate mounting rapid anti-intruder responses, as responses to intruder-playback occurred significantly earlier when the dominant male was sentineling rather than foraging at playback onset. Together, our findings provide rare support for the hypothesis that sentinel behavior plays a role in intrasexual competition, and so highlight the potential for sexually selected direct benefits to shape its expression in this and other social vertebrates.}, } @article {pmid27656085, year = {2016}, author = {He, QQ and Wu, JJ and Ji, T and Tao, Y and Mace, R}, title = {Not leaving home: grandmothers and male dispersal in a duolocal human society.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {27}, number = {5}, pages = {1343-1352}, pmid = {27656085}, issn = {1045-2249}, abstract = {Models suggest that dispersal patterns will influence age- and sex-dependent helping behavior in social species. Duolocal social systems (where neither sex disperses and mating is outside the group) are predicted to be associated with mothers favoring sons over daughters (because the latter are in reproductive competition with each other). Other models predict daughter-biased investment when benefits of wealth to sons are less than daughters. Here, we test whether sex-biased investment is occurring in the duolocal Mosuo of southwestern China. Using demographic and observational data from Mosuo, we show support for both hypotheses, in that 1) males are more likely to disperse from their natal household if their mother dies, but females are not; 2) a large number of brothers increases the likelihood that both females and males disperse, whereas a large number of sisters only increases female dispersal; 3) mothers help daughters reproduce earlier and reduce death risk of daughter's children, but not sons or sons' children; 4) data on multiple paternity show that female reproductive success does not suffer from multiple partners, and in males multiple mates are associated with higher reproductive success, indicating that mothers can benefit from investing in their sons' mating effort; and 5) gift decisions reveal similar kin effects to those shown in the demographic data, with mothers helping adult daughters and adult sons equally, but helping only her daughter's children, not her son's children. Mosuo mothers may invest resources for parental investment in their daughters and their offspring, while investing in their sons mating effort.}, } @article {pmid27648229, year = {2016}, author = {Städele, V and Vigilant, L}, title = {Strategies for determining kinship in wild populations using genetic data.}, journal = {Ecology and evolution}, volume = {6}, number = {17}, pages = {6107-6120}, pmid = {27648229}, issn = {2045-7758}, abstract = {Knowledge of kin relationships between members of wild animal populations has broad application in ecology and evolution research by allowing the investigation of dispersal dynamics, mating systems, inbreeding avoidance, kin recognition, and kin selection as well as aiding the management of endangered populations. However, the assessment of kinship among members of wild animal populations is difficult in the absence of detailed multigenerational pedigrees. Here, we first review the distinction between genetic relatedness and kinship derived from pedigrees and how this makes the identification of kin using genetic data inherently challenging. We then describe useful approaches to kinship classification, such as parentage analysis and sibship reconstruction, and explain how the combined use of marker systems with biparental and uniparental inheritance, demographic information, likelihood analyses, relatedness coefficients, and estimation of misclassification rates can yield reliable classifications of kinship in groups with complex kin structures. We outline alternative approaches for cases in which explicit knowledge of dyadic kinship is not necessary, but indirect inferences about kinship on a group- or population-wide scale suffice, such as whether more highly related dyads are in closer spatial proximity. Although analysis of highly variable microsatellite loci is still the dominant approach for studies on wild populations, we describe how the long-awaited use of large-scale single-nucleotide polymorphism and sequencing data derived from noninvasive low-quality samples may eventually lead to highly accurate assessments of varying degrees of kinship in wild populations.}, } @article {pmid27600591, year = {2017}, author = {Lahvis, GP}, title = {Social Reward and Empathy as Proximal Contributions to Altruism: The Camaraderie Effect.}, journal = {Current topics in behavioral neurosciences}, volume = {30}, number = {}, pages = {127-157}, pmid = {27600591}, issn = {1866-3370}, support = {R01 DA022543/DA/NIDA NIH HHS/United States ; }, mesh = {*Altruism ; Animals ; Empathy/physiology ; Humans ; Motivation/physiology ; *Reward ; Rodentia ; }, abstract = {Natural selection favors individuals to act in their own interests, implying that wild animals experience a competitive psychology. Animals in the wild also express helping behaviors, presumably at their own expense and suggestive of a more compassionate psychology. This apparent paradox can be partially explained by ultimate mechanisms that include kin selection, reciprocity, and multilevel selection, yet some theorists argue such ultimate explanations may not be sufficient and that an additional "stake in others" is necessary for altruism's evolution. We suggest this stake is the "camaraderie effect," a by-product of two highly adaptive psychological experiences: social motivation and empathy. Rodents can derive pleasure from access to others and this appetite for social rewards motivates individuals to live together, a valuable psychology when group living is adaptive. Rodents can also experience empathy, the generation of an affective state more appropriate to the situation of another compared to one's own. Empathy is not a compassionate feeling but it has useful predictive value. For instance, empathy allows an individual to feel an unperceived danger from social cues. Empathy of another's stance toward one's self would predict either social acceptance or ostracism and amplify one's physiological sensitivity to social isolation, including impaired immune responses and delayed wound healing. By contrast, altruistic behaviors would promote well-being in others and feelings of camaraderie from others, thereby improving one's own physiological well-being. Together, these affective states engender a stake in others necessary for the expression of altruistic behavior.}, } @article {pmid27590987, year = {2016}, author = {Lehtonen, J}, title = {Multilevel Selection in Kin Selection Language.}, journal = {Trends in ecology & evolution}, volume = {31}, number = {10}, pages = {752-762}, doi = {10.1016/j.tree.2016.07.006}, pmid = {27590987}, issn = {1872-8383}, mesh = {Animals ; *Biological Evolution ; *Selection, Genetic ; Social Behavior ; }, abstract = {Few issues have raised more debate among evolutionary biologists than kin selection (KS) versus multilevel selection (MLS). They are formally equivalent, but use different-looking mathematical approaches, and are not causally equivalent: for a given problem KS can be a more suitable causal explanation than MLS, and vice versa. Methods for analyzing a given model from both viewpoints would therefore be valuable. I argue that there is often an easy way to achieve this: MLS can be written using the components of KS. This applies to the very general regression approach as well as to the practical evolutionarily stable strategy (ESS) maximization approach, and can hence be used to analyze many common ESS models from a multilevel perspective. I demonstrate this with example models of gamete competition and limitation.}, } @article {pmid27588754, year = {2016}, author = {Jacob, G and Prévot, AC and Baudry, E}, title = {Feral Pigeons (Columba livia) Prefer Genetically Similar Mates despite Inbreeding Depression.}, journal = {PloS one}, volume = {11}, number = {9}, pages = {e0162451}, pmid = {27588754}, issn = {1932-6203}, mesh = {Animals ; Columbidae/*physiology ; Female ; *Inbreeding Depression ; Male ; Mating Preference, Animal/*physiology ; Reproduction/*physiology ; Sexual Behavior, Animal/physiology ; }, abstract = {Avoidance of mating between related individuals is usually considered adaptive because it decreases the probability of inbreeding depression in offspring. However, mating between related partners can be adaptive if outbreeding depression is stronger than inbreeding depression or if females gain inclusive fitness benefits by mating with close kin. In the present study, we used microsatellite data to infer the parentage of juveniles born in a French colony of feral pigeons, which allowed us to deduce parent pairs. Despite detectable inbreeding depression, we found that pairwise relatedness between mates was significantly higher than between nonmates, with a mean coefficient of relatedness between mates of 0.065, approximately half the theoretical value for first cousins. This higher relatedness between mates cannot be explained by spatial genetic structure in this colonial bird; it therefore probably results from an active choice. As inbreeding but not outbreeding depression is observed in the study population, this finding accords with the idea that mating with genetically similar mates can confer a benefit in terms of inclusive fitness. Our results and published evidence suggest that preference for related individuals as mates might be relatively frequent in birds.}, } @article {pmid27579491, year = {2016}, author = {Pfefferle, D and Hammerschmidt, K and Mundry, R and Ruiz-Lambides, AV and Fischer, J and Widdig, A}, title = {Does the Structure of Female Rhesus Macaque Coo Calls Reflect Relatedness and/or Familiarity?.}, journal = {PloS one}, volume = {11}, number = {8}, pages = {e0161133}, pmid = {27579491}, issn = {1932-6203}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Animals ; Female ; Macaca mulatta ; Vocalization, Animal/*physiology ; }, abstract = {In social animals, kin relations strongly shape the social structure of a group. In female-bonded species, maternal relatedness is likely to be mediated via familiarity, but evidence is accumulating that non-human primates are able to recognize kin that they are not familiar with and adjust their behavior accordingly. In playback experiments, female rhesus macaques showed increased interest in 'coo' calls produced by unfamiliar paternal half-sisters compared to 'coo' calls produced by unfamiliar unrelated females, suggesting that these calls should have some common structural characteristics that facilitate the discrimination of kin from non-kin. Here we analyzed 'coo' calls of 67 adult female rhesus macaques from four groups and seven matrilines living on the island of Cayo Santiago (Puerto Rico). We tested whether the call structure of closely maternal and/or paternal related females, as determined from extensive pedigree data, differed from the call structure of unrelated females, while controlling for familiarity (i.e., group-matrilineal membership and age difference) of subjects. In contrast to our expectation, kinship did not predict similarities in 'coo' call structure, whereas 'coo' structure was more similar when produced by females of similar age as well as by females with higher familiarity, suggesting that experience is more decisive than genetic background. The high number of individuals in the analysis and the high accuracy of the assignment of calls to individuals render a lack of power as an unlikely explanation. Thus, based on the results of this study, kin recognition in rhesus monkeys does neither appear to be based on the assessment of self-similarity, nor on the comparison among related subjects (i.e., acoustic phenotype matching), but appears to be mediated by different or multiple cues. Furthermore, the results support the notion that frequent social interactions result in increasing acoustic similarity within largely innate call types ('vocal accommodation').}, } @article {pmid27576465, year = {2016}, author = {Weiß, BM and Kulik, L and Ruiz-Lambides, AV and Widdig, A}, title = {Individual dispersal decisions affect fitness via maternal rank effects in male rhesus macaques.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {32212}, pmid = {27576465}, issn = {2045-2322}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Animal Migration ; Animals ; Female ; Genetic Fitness ; Macaca mulatta/*physiology ; Male ; Reproduction ; Sex Ratio ; Sexual Behavior, Animal ; Social Behavior ; Social Dominance ; }, abstract = {Natal dispersal may have considerable social, ecological and evolutionary consequences. While species-specific dispersal strategies have received much attention, individual variation in dispersal decisions and its fitness consequences remain poorly understood. We investigated causes and consequences of natal dispersal age in rhesus macaques (Macaca mulatta), a species with male dispersal. Using long-term demographic and genetic data from a semi-free ranging population on Cayo Santiago, Puerto Rico, we analysed how the social environment such as maternal family, group and population characteristics affected the age at which males leave their natal group. While natal dispersal age was unrelated to most measures of group or population structure, our study confirmed earlier findings that sons of high-ranking mothers dispersed later than sons of low-ranking ones. Natal dispersal age did not affect males' subsequent survival, but males dispersing later were more likely to reproduce. Late dispersers were likely to start reproducing while still residing in their natal group, frequently produced extra-group offspring before natal dispersal and subsequently dispersed to the group in which they had fathered offspring more likely than expected. Hence, the timing of natal dispersal was affected by maternal rank and influenced male reproduction, which, in turn affected which group males dispersed to.}, } @article {pmid27569292, year = {2017}, author = {van Veelen, M and Allen, B and Hoffman, M and Simon, B and Veller, C}, title = {Hamilton's rule.}, journal = {Journal of theoretical biology}, volume = {414}, number = {}, pages = {176-230}, doi = {10.1016/j.jtbi.2016.08.019}, pmid = {27569292}, issn = {1095-8541}, mesh = {Animals ; *Biological Evolution ; Humans ; *Models, Biological ; Selection, Genetic/*physiology ; }, abstract = {This paper reviews and addresses a variety of issues relating to inclusive fitness. The main question is: are there limits to the generality of inclusive fitness, and if so, what are the perimeters of the domain within which inclusive fitness works? This question is addressed using two well-known tools from evolutionary theory: the replicator dynamics, and adaptive dynamics. Both are combined with population structure. How generally Hamilton's rule applies depends on how costs and benefits are defined. We therefore consider costs and benefits following from Karlin and Matessi's (1983) "counterfactual method", and costs and benefits as defined by the "regression method" (Gardner et al., 2011). With the latter definition of costs and benefits, Hamilton's rule always indicates the direction of selection correctly, and with the former it does not. How these two definitions can meaningfully be interpreted is also discussed. We also consider cases where the qualitative claim that relatedness fosters cooperation holds, even if Hamilton's rule as a quantitative prediction does not. We furthermore find out what the relation is between Hamilton's rule and Fisher's Fundamental Theorem of Natural Selection. We also consider cancellation effects - which is the most important deepening of our understanding of when altruism is selected for. Finally we also explore the remarkable (im)possibilities for empirical testing with either definition of costs and benefits in Hamilton's rule.}, } @article {pmid27561630, year = {2016}, author = {Nesse, RM}, title = {Social selection is a powerful explanation for prosociality.}, journal = {The Behavioral and brain sciences}, volume = {39}, number = {}, pages = {e47}, doi = {10.1017/S0140525X15000308}, pmid = {27561630}, issn = {1469-1825}, mesh = {Biological Evolution ; Humans ; *Interpersonal Relations ; Phenotype ; Reproduction ; Selection, Genetic ; *Social Behavior ; }, abstract = {Cultural group selection helps explain human cooperation, but social selection offers a complementary, more powerful explanation. Just as sexual selection shapes extreme traits that increase matings, social selection shapes extreme traits that make individuals preferred social partners. Self-interested partner choices create strong and possibly runaway selection for prosocial traits, without requiring group selection, kin selection, or reciprocity.}, } @article {pmid27554604, year = {2016}, author = {Green, JP and Freckleton, RP and Hatchwell, BJ}, title = {Variation in helper effort among cooperatively breeding bird species is consistent with Hamilton's Rule.}, journal = {Nature communications}, volume = {7}, number = {}, pages = {12663}, pmid = {27554604}, issn = {2041-1723}, mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; Birds/*physiology ; Breeding ; Cooperative Behavior ; Ecosystem ; Female ; Helping Behavior ; Male ; Models, Biological ; Phylogeny ; Sex Ratio ; Social Behavior ; Species Specificity ; }, abstract = {Investment by helpers in cooperative breeding systems is extremely variable among species, but this variation is currently unexplained. Inclusive fitness theory predicts that, all else being equal, cooperative investment should correlate positively with the relatedness of helpers to the recipients of their care. We test this prediction in a comparative analysis of helper investment in 36 cooperatively breeding bird species. We show that species-specific helper contributions to cooperative brood care increase as the mean relatedness between helpers and recipients increases. Helper contributions are also related to the sex ratio of helpers, but neither group size nor the proportion of nests with helpers influence helper effort. Our findings support the hypothesis that variation in helping behaviour among cooperatively breeding birds is consistent with Hamilton's rule, indicating a key role for kin selection in the evolution of cooperative investment in social birds.}, } @article {pmid27534524, year = {2016}, author = {Kowald, A and Kirkwood, TBL}, title = {Can aging be programmed? A critical literature review.}, journal = {Aging cell}, volume = {15}, number = {6}, pages = {986-998}, pmid = {27534524}, issn = {1474-9726}, abstract = {The evolution of the aging process has long been a biological riddle, because it is difficult to explain the evolution of a trait that has apparently no benefit to the individual. Over 60 years ago, Medawar realized that the force of natural selection declines with chronological age because of unavoidable environmental risks. This forms the basis of the mainstream view that aging arises as a consequence of a declining selection pressure to maintain the physiological functioning of living beings forever. Over recent years, however, a number of articles have appeared that nevertheless propose the existence of specific aging genes; that is, that the aging process is genetically programmed. If this view were correct, it would have serious implications for experiments to understand and postpone aging. Therefore, we studied in detail various specific proposals why aging should be programmed. We find that not a single one withstands close scrutiny of its assumptions or simulation results. Nonprogrammed aging theories based on the insight of Medawar (as further developed by Hamilton and Charlesworth) are still the best explanation for the evolution of the aging process. We hope that this analysis helps to clarify the problems associated with the idea of programmed aging.}, } @article {pmid27485635, year = {2016}, author = {Helanterä, H and Kulmuni, J and Pamilo, P}, title = {Sex allocation conflict between queens and workers in Formica pratensis wood ants predicts seasonal sex ratio variation.}, journal = {Evolution; international journal of organic evolution}, volume = {70}, number = {10}, pages = {2387-2394}, doi = {10.1111/evo.13018}, pmid = {27485635}, issn = {1558-5646}, mesh = {Animals ; Ants/*genetics/physiology ; Female ; Haploidy ; Male ; *Seasons ; *Sex Ratio ; }, abstract = {Sex allocation theory predicts parents should adjust their investment in male and female offspring in a way that increases parental fitness. This has been shown in several species and selective contexts. Yet, seasonal sex ratio variation within species and its underlying causes are poorly understood. Here, we study sex allocation variation in the wood ant Formica pratensis. This species displays conflict over colony sex ratio as workers and queens prefer different investment in male and female offspring, owing to haplodiploidy and relatedness asymmetries. It is unique among Formica ants because it produces two separate sexual offspring cohorts per season. We predict sex ratios to be closer to queen optimum in the early cohort but more female-biased and closer to worker optimum in the later one. This is because the power of workers to manipulate colony sex ratio varies seasonally with the availability of diploid eggs. Consistently, more female-biased sex ratios in the later offspring cohort over a three-year sampling period from 93 colonies clearly support our prediction. The resulting seasonal alternation of sex ratios between queen and worker optima is a novel demonstration how understanding constraints of sex ratio adjustment increases our ability to predict sex ratio variation.}, } @article {pmid27483372, year = {2016}, author = {Makowicz, AM and Tiedemann, R and Steele, RN and Schlupp, I}, title = {Kin Recognition in a Clonal Fish, Poecilia formosa.}, journal = {PloS one}, volume = {11}, number = {8}, pages = {e0158442}, pmid = {27483372}, issn = {1932-6203}, mesh = {Aggression ; Animals ; Behavior, Animal ; Female ; Genetic Variation ; Genetics, Population ; Male ; Microsatellite Repeats ; Poecilia/anatomy & histology/*genetics/physiology ; Selection, Genetic ; Social Behavior ; Texas ; }, abstract = {Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clones, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity.}, } @article {pmid27480245, year = {2016}, author = {Jacob, S and Wehi, P and Clobert, J and Legrand, D and Schtickzelle, N and Huet, M and Chaine, A}, title = {Cooperation-mediated plasticity in dispersal and colonization.}, journal = {Evolution; international journal of organic evolution}, volume = {70}, number = {10}, pages = {2336-2345}, doi = {10.1111/evo.13028}, pmid = {27480245}, issn = {1558-5646}, mesh = {Biological Evolution ; Cell Aggregation/genetics ; Genotype ; *Models, Genetic ; Tetrahymena thermophila/*genetics/physiology ; }, abstract = {Kin selection theory predicts that costly cooperative behaviors evolve most readily when directed toward kin. Dispersal plays a controversial role in the evolution of cooperation: dispersal decreases local population relatedness and thus opposes the evolution of cooperation, but limited dispersal increases kin competition and can negate the benefits of cooperation. Theoretical work has suggested that plasticity of dispersal, where individuals can adjust their dispersal decisions according to the social context, might help resolve this paradox and promote the evolution of cooperation. Here, we experimentally tested the hypothesis that conditional dispersal decisions are mediated by a cooperative strategy: we quantified the density-dependent dispersal decisions and subsequent colonization efficiency from single cells or groups of cells among six genetic strains of the unicellular Tetrahymena thermophila that differ in their aggregation level (high, medium, and low), a behavior associated with cooperation strategy. We found that the plastic reaction norms of dispersal rate relative to density differed according to aggregation level: highly aggregative genotypes showed negative density-dependent dispersal, whereas low-aggregation genotypes showed maximum dispersal rates at intermediate density, and medium-aggregation genotypes showed density-independent dispersal with intermediate dispersal rate. Dispersers from highly aggregative genotypes had specialized long-distance dispersal phenotypes, contrary to low-aggregation genotypes; medium-aggregation genotypes showing intermediate dispersal phenotype. Moreover, highly aggregation genotypes showed evidence for beneficial kin-cooperation during dispersal. Our experimental results should help to resolve the evolutionary conflict between cooperation and dispersal: cooperative individuals are expected to avoid kin-competition by dispersing long distances, but maintain the benefits of cooperation by dispersing in small groups.}, } @article {pmid27478299, year = {2016}, author = {Kerhoas, D and Kulik, L and Perwitasari-Farajallah, D and Agil, M and Engelhardt, A and Widdig, A}, title = {Mother-male bond, but not paternity, influences male-infant affiliation in wild crested macaques.}, journal = {Behavioral ecology and sociobiology}, volume = {70}, number = {}, pages = {1117-1130}, pmid = {27478299}, issn = {0340-5443}, abstract = {ABSTRACT: In promiscuous primates, interactions between adult males and infants have rarely been investigated. However, recent evidence suggests that male affiliation towards infants has an influence on several aspects of the infants' life. Furthermore, affiliations may be associated with male reproductive strategy. In this study, we examined which social factors influenced male-infant affiliation initiated by either male or infant, in wild crested macaques (Macaca nigra). We combined behavioral data and genetic paternity analysis from 30 infants living in three wild groups in Tangkoko Reserve, Indonesia. Our results indicate that adult males and infants do not interact at random, but rather form preferential associations. The social factors with the highest influence on infant-initiated interactions were male rank and male association with the infant's mother. While infants initiated affiliations with males more often in the absence of their mothers, adult males initiated more affiliations with infants when their mothers were present. Furthermore, males initiated affiliations more often when they were in the same group at the time the infant was conceived, when they held a high dominance rank, or when they had a close relationship with the mother. Interestingly, paternity did not affect male-infant affiliation despite being highly skewed in this species. Overall, our results suggest that adult males potentially associate with an infant to secure future mating with the mother. Infants are more likely to associate with a male to receive better support, suggesting a strategy to increase the chance of infant survival in a primate society with high infant mortality.

SIGNIFICANCE STATEMENT: We explore social relationships between males and infants in a promiscuous primate, the wild crested macaque. Our novel approach addresses the nature of affiliations both from males' and infants' perspectives. The results show that males and infants form preferential associations. Male-female affiliation, but not paternity, was a significant predictor of interactions initiated both by males and infants. Males initiated more interactions towards infants when the mother was in proximity, while infants initiated more interactions in her absence. Finally, high-ranking males were more likely to initiate interactions towards infants. We demonstrated that paternity is not a good predictor of male-infant affiliations, even in a species with a high reproductive skew and a relatively high confidence of paternity. Our paper is one of the first to show that infants are active agents in establishing and maintaining preferential relationships with males.}, } @article {pmid27468393, year = {2016}, author = {Jaffe, K}, title = {Extended inclusive fitness theory: synergy and assortment drives the evolutionary dynamics in biology and economics.}, journal = {SpringerPlus}, volume = {5}, number = {1}, pages = {1092}, pmid = {27468393}, issn = {2193-1801}, abstract = {W.D. Hamilton's Inclusive Fitness Theory explains the conditions that favor the emergence and maintenance of social cooperation. Today we know that these include direct and indirect benefits an agent obtains by its actions, and through interactions with kin and with genetically unrelated individuals. That is, in addition to kin-selection, assortation or homophily, and social synergies drive the evolution of cooperation. An Extended Inclusive Fitness Theory (EIFT) synthesizes the natural selection forces acting on biological evolution and on human economic interactions by assuming that natural selection driven by inclusive fitness produces agents with utility functions that exploit assortation and synergistic opportunities. This formulation allows to estimate sustainable cost/benefit threshold ratios of cooperation among organisms and/or economic agents, using existent analytical tools, illuminating our understanding of the dynamic nature of society, the evolution of cooperation among kin and non-kin, inter-specific cooperation, co-evolution, symbioses, division of labor and social synergies. EIFT helps to promote an interdisciplinary cross fertilization of the understanding of synergy by, for example, allowing to describe the role for division of labor in the emergence of social synergies, providing an integrated framework for the study of both, biological evolution of social behavior and economic market dynamics. Another example is a bio-economic understanding of the motivations of terrorists, which identifies different forms of terrorism.}, } @article {pmid27451903, year = {2016}, author = {Jaeggi, AV and Hooper, PL and Beheim, BA and Kaplan, H and Gurven, M}, title = {Reciprocal Exchange Patterned by Market Forces Helps Explain Cooperation in a Small-Scale Society.}, journal = {Current biology : CB}, volume = {26}, number = {16}, pages = {2180-2187}, doi = {10.1016/j.cub.2016.06.019}, pmid = {27451903}, issn = {1879-0445}, support = {R01 AG024119/AG/NIA NIH HHS/United States ; R56 AG024119/AG/NIA NIH HHS/United States ; }, mesh = {Bayes Theorem ; Bolivia ; *Cooperative Behavior ; Farmers/*psychology ; Humans ; Indians, South American/*psychology ; *Interpersonal Relations ; Models, Theoretical ; }, abstract = {Social organisms sometimes depend on help from reciprocating partners to solve adaptive problems [1], and individual cooperation strategies should aim to offer high supply commodities at low cost to the donor in exchange for high-demand commodities with large return benefits [2, 3]. Although such market dynamics have been documented in some animals [4-7], naturalistic studies of human cooperation are often limited by focusing on single commodities [8]. We analyzed cooperation in five domains (meat sharing, produce sharing, field labor, childcare, and sick care) among 2,161 household dyads of Tsimane' horticulturalists, using Bayesian multilevel models and information-theoretic model comparison. Across domains, the best-fit models included kinship and residential proximity, exchanges in kind and across domains, measures of supply and demand and their interactions with exchange, and household-specific exchange slopes. In these best models, giving, receiving, and reciprocating were to some extent shaped by market forces, and reciprocal exchange across domains had a strong partial effect on cooperation independent of more exogenous factors like kinship and proximity. Our results support the view that reciprocal exchange can provide a reliable solution to adaptive problems [8-11]. Although individual strategies patterned by market forces may generate gains from trade in any species [3], humans' slow life history and skill-intensive foraging niche favor specialization and create interdependence [12, 13], thus stabilizing cooperation and fostering divisions of labor even in informal economies [14, 15].}, } @article {pmid27430596, year = {2016}, author = {Bretl, DJ and Kirby, JR}, title = {Molecular Mechanisms of Signaling in Myxococcus xanthus Development.}, journal = {Journal of molecular biology}, volume = {428}, number = {19}, pages = {3805-3830}, doi = {10.1016/j.jmb.2016.07.008}, pmid = {27430596}, issn = {1089-8638}, mesh = {*Gene Expression Regulation, Bacterial ; *Microbial Interactions ; Myxococcus xanthus/*growth & development ; *Signal Transduction ; }, abstract = {Myxococcus xanthus is an environmental bacterium that displays a complex life cycle that includes motility, predation, multicellular fruiting body development, and sporulation. Given the elaborate fruiting body development of this bacterial species, M. xanthus has served as a model organism for the study of multicellular development of bacteria, and a remarkable number of genes have been identified that contribute to the regulation of this highly dynamic process. Included among these developmental factors is a robust repertoire of signaling proteins, which have arisen from extensive gene duplication in M. xanthus and related species. In this review, we explore several aspects of the molecular mechanisms of signaling in M. xanthus development. This includes mechanisms of kin selection, single-cell sensing of nutrient depletion and the stringent response, the production of and response to extracellular population cues, and the contribution of several two-component signaling systems regulating developmental transcriptional programs. Collectively, these signaling mechanisms function to tightly regulate the sensing of nutrient depletion, the aggregation of populations of cells, and the temporal and spatial formation of complex fruiting bodies and sporulation of M. xanthus.}, } @article {pmid27395400, year = {2016}, author = {Morozov, A}, title = {Modelling biological evolution: Linking mathematical theories with empirical realities.}, journal = {Journal of theoretical biology}, volume = {405}, number = {}, pages = {1-4}, doi = {10.1016/j.jtbi.2016.07.007}, pmid = {27395400}, issn = {1095-8541}, mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; Empirical Research ; Humans ; *Models, Theoretical ; }, } @article {pmid30349177, year = {2016}, author = {Stern, CA and Dickinson, JL}, title = {Effects of load-lightening and delayed extrapair benefits on the fitness consequences of helping behavior.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {27}, number = {4}, pages = {1078-1086}, pmid = {30349177}, issn = {1045-2249}, abstract = {In most cooperative breeders, helping is directed at close kin, allowing helpers to gain indirect fitness benefits by increasing the reproductive success of close relatives, usually their parents. Extrapair paternity (EPP) occurs at high rates in some cooperative breeders, reducing the relatedness of helpers to the young they help raise. Even so, a son that helps is related to the brood by at least 0.25 through his mother and to within-pair young by 0.5, whereas a potential helper that has EPP in his own nest is related only to the offspring he sires and unrelated to any extrapair offspring. In birds, EPP often favors older males, which in the extreme case can result in sons being more closely related to young in their parents' nest than to young in their own nests. The fitness benefit of helping will thus be enhanced if helping lightens the workload and increases survival of helpers and their fathers, enabling them to become old, hyper-successful extrapair sires. Here, we develop and analyze a proof-of-concept model, grounded in the western bluebird (Sialia mexicana) system, demonstrating the conditions under which high population levels of EPP can generate inclusive fitness benefits of helping behavior that outweigh the costs. This model provides a new perspective on the relationship between EPP and helping behavior in cooperative breeders and suggests a strong need for empirical work to gather unprecedented data on paternity over the lifetime of helpers and their parents.}, } @article {pmid27359217, year = {2016}, author = {Wall, D}, title = {Kin Recognition in Bacteria.}, journal = {Annual review of microbiology}, volume = {70}, number = {}, pages = {143-160}, pmid = {27359217}, issn = {1545-3251}, support = {R01 GM101449/GM/NIGMS NIH HHS/United States ; }, mesh = {Bacteria/genetics ; *Bacterial Physiological Phenomena ; Bacterial Proteins/genetics/*metabolism ; Gene Expression Regulation, Bacterial ; }, abstract = {The ability of bacteria to recognize kin provides a means to form social groups. In turn these groups can lead to cooperative behaviors that surpass the ability of the individual. Kin recognition involves specific biochemical interactions between a receptor(s) and an identification molecule(s). Recognition specificity, ensuring that nonkin are excluded and kin are included, is critical and depends on the number of loci and polymorphisms involved. After recognition and biochemical perception, the common ensuing cooperative behaviors include biofilm formation, quorum responses, development, and swarming motility. Although kin recognition is a fundamental mechanism through which cells might interact, microbiologists are only beginning to explore the topic. This review considers both molecular and theoretical aspects of bacterial kin recognition. Consideration is also given to bacterial diversity, genetic relatedness, kin selection theory, and mechanisms of recognition.}, } @article {pmid27350328, year = {2016}, author = {Loope, KJ}, title = {Matricide and queen sex allocation in a yellowjacket wasp.}, journal = {Die Naturwissenschaften}, volume = {103}, number = {7-8}, pages = {57}, pmid = {27350328}, issn = {1432-1904}, mesh = {Animals ; *Behavior, Animal ; Female ; Male ; Oviposition ; Reproduction/physiology ; Sex Ratio ; Wasps/*physiology ; }, abstract = {In many colonies of social insects, the workers compete with each other and with the queen over the production of the colony's males. In some species of social bees and wasps with annual societies, this intra-colony conflict even results in matricide-the killing of the colony's irreplaceable queen by a daughter worker. In colonies with low effective paternity and high worker-worker relatedness, workers value worker-laid males more than queen-laid males, and thus may benefit from queen killing. Workers gain by eliminating the queen because she is a competing source of male eggs and actively inhibits worker reproduction through policing. However, matricide may be costly to workers if it reduces the production of valuable new queens and workers. Here, I test a theoretical prediction regarding the timing of matricide in a wasp, Dolichovespula arenaria, recently shown to have facultative matricide based on intra-colony relatedness. Using analyses of collected, mature colonies and a surgical manipulation preventing queens from laying female eggs, I show that workers do not preferentially kill queens who are only producing male eggs. Instead, workers sometimes kill queens laying valuable females, suggesting a high cost of matricide. Although matricide is common and typically occurs only in low-paternity colonies, it seems that workers sometimes pay substantial costs in this expression of conflict over male parentage.}, } @article {pmid27336694, year = {2016}, author = {Lu, HJ and Chang, L}, title = {Resource allocation to kin, friends, and strangers by 3- to 6-year-old children.}, journal = {Journal of experimental child psychology}, volume = {150}, number = {}, pages = {194-206}, doi = {10.1016/j.jecp.2016.05.018}, pmid = {27336694}, issn = {1096-0457}, mesh = {*Altruism ; Analysis of Variance ; Child ; Child, Preschool ; Discrimination, Psychological ; Family/*psychology ; Family Relations ; Female ; Friends/*psychology ; Humans ; Interpersonal Relations ; Male ; *Resource Allocation ; Theory of Mind/physiology ; }, abstract = {Kin altruism has been widely observed across species, including humans. However, few studies have discussed the development of kin altruism or its relationship with theory of mind. In this study, 3- to 6-year-old children allocated resources between themselves and kin, a friend, or a stranger in three allocation tasks where the allocation either incurred a cost, incurred no cost, or conferred a disadvantage. The results showed that, compared with 3- and 4-year-olds, 5- and 6-year-olds acted more altruistically toward kin and that kin altruism was uncorrelated with theory of mind. These findings suggest that, within the context of resource allocation, kin altruism emerges toward the end of early childhood and probably differs from other prosocial behavior that relies solely on the understanding of others' perspectives.}, } @article {pmid27322127, year = {2016}, author = {Dugas, MB and McCormack, L and Gadau, A and Martin, RA}, title = {Choosy Cannibals Preferentially Consume Siblings with Relatively Low Fitness Prospects.}, journal = {The American naturalist}, volume = {188}, number = {1}, pages = {124-131}, doi = {10.1086/686729}, pmid = {27322127}, issn = {1537-5323}, mesh = {Animals ; *Anura ; *Cannibalism ; Environment ; *Genetic Fitness ; Larva ; Siblings ; }, abstract = {When an individual can selfishly cannibalize a relative or altruistically set it free, the benefits of altruism will be positively associated with the relative's fitness prospects (the benefits it receives from altruism). We tested the prediction that altruism should be preferentially directed toward high-quality relatives using larvae of the New Mexican spadefoot toad (Spea multiplicata), a species in which tadpoles plastically express omnivore and carnivore ecomorphs. In a no-choice design, we presented carnivores with sibling or nonsibling omnivores varying in developmental stage, which is positively associated with survival in this toad's ephemeral larval environment. There was a significant interaction between relatedness and developmental stage on the probability of cannibalism: carnivores were overall more likely to cannibalize less developed omnivores, but this effect was exaggerated when the potential victim was a sibling. This evidence that altruists favor relatives with high fitness prospects highlights the numerous factors shaping altruism's payoffs.}, } @article {pmid27305045, year = {2016}, author = {Jones, D}, title = {Socially Enforced Nepotism: How Norms and Reputation Can Amplify Kin Altruism.}, journal = {PloS one}, volume = {11}, number = {6}, pages = {e0155596}, pmid = {27305045}, issn = {1932-6203}, mesh = {Algorithms ; *Altruism ; *Cooperative Behavior ; Family ; Humans ; *Interpersonal Relations ; Models, Theoretical ; *Social Behavior ; }, abstract = {Kin selection, which can lead organisms to behave altruistically to their genetic relatives, works differently when-as is often the case in human societies-altruism can be boosted by social pressure. Here I present a model of social norms enforced by indirect reciprocity. In the model there are many alternative stable allocations of rewards ("distributional norms"); a stable norm is stable in the sense that each player is best off following the norm if other players do the same. Stable norms vary widely in how equally they reward players with unequal abilities. In a population of mixed groups (some group members follow one norm, some follow another, and some compromise) with modest within-group coefficients of relatedness, selection within groups favors those who compromise, and selection between groups favors generous generalized reciprocity rather than balanced reciprocity. Thus evolved social norms can amplify kin altruism, giving rise to a uniquely human mode of kin-based sociality distinct from spontaneous altruism among close kin, or cooperation among non-kin.}, } @article {pmid27282468, year = {2016}, author = {Lahdenperä, M and Mar, KU and Lummaa, V}, title = {Nearby grandmother enhances calf survival and reproduction in Asian elephants.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {27213}, pmid = {27282468}, issn = {2045-2322}, mesh = {Animals ; Biological Evolution ; Elephants/*physiology ; Female ; *Genetic Fitness ; Helping Behavior ; Longevity ; *Reproduction ; Survival Analysis ; }, abstract = {Usually animals reproduce into old age, but a few species such as humans and killer whales can live decades after their last reproduction. The grandmother hypothesis proposes that such life-history evolved through older females switching to invest in their existing (grand)offspring, thereby increasing their inclusive fitness and selection for post-reproductive lifespan. However, positive grandmother effects are also found in non-menopausal taxa, but evidence of their associated fitness effects is rare and only a few tests of the hypothesis in such species exist. Here we investigate the grandmother effects in Asian elephants. Using a multigenerational demographic dataset on semi-captive elephants in Myanmar, we found that grandcalves from young mothers (<20 years) had 8 times lower mortality risk if the grandmother resided with her grandcalf compared to grandmothers residing elsewhere. Resident grandmothers also decreased their daughters' inter-birth intervals by one year. In contrast to the hypothesis predictions, the grandmother's own reproductive status did not modify such grandmother benefits. That elephant grandmothers increased their inclusive fitness by enhancing their daughter's reproductive rate and success irrespective of their own reproductive status suggests that fitness-enhancing grandmaternal effects are widespread, and challenge the view that grandmother effects alone select for menopause coupled with long post-reproductive lifespan.}, } @article {pmid27282317, year = {2016}, author = {Lehmann, L and Mullon, C and Akçay, E and Van Cleve, J}, title = {Invasion fitness, inclusive fitness, and reproductive numbers in heterogeneous populations.}, journal = {Evolution; international journal of organic evolution}, volume = {70}, number = {8}, pages = {1689-1702}, doi = {10.1111/evo.12980}, pmid = {27282317}, issn = {1558-5646}, mesh = {*Genetic Fitness ; *Introduced Species ; *Models, Genetic ; Phenotype ; *Reproduction ; }, abstract = {How should fitness be measured to determine which phenotype or "strategy" is uninvadable when evolution occurs in a group-structured population subject to local demographic and environmental heterogeneity? Several fitness measures, such as basic reproductive number, lifetime dispersal success of a local lineage, or inclusive fitness have been proposed to address this question, but the relationships between them and their generality remains unclear. Here, we ascertain uninvadability (all mutant strategies always go extinct) in terms of the asymptotic per capita number of mutant copies produced by a mutant lineage arising as a single copy in a resident population ("invasion fitness"). We show that from invasion fitness uninvadability is equivalently characterized by at least three conceptually distinct fitness measures: (i) lineage fitness, giving the average individual fitness of a randomly sampled mutant lineage member; (ii) inclusive fitness, giving a reproductive value weighted average of the direct fitness costs and relatedness weighted indirect fitness benefits accruing to a randomly sampled mutant lineage member; and (iii) basic reproductive number (and variations thereof) giving lifetime success of a lineage in a single group, and which is an invasion fitness proxy. Our analysis connects approaches that have been deemed different, generalizes the exact version of inclusive fitness to class-structured populations, and provides a biological interpretation of natural selection on a mutant allele under arbitrary strength of selection.}, } @article {pmid27277401, year = {2016}, author = {Zink, AG and Lyon, BE}, title = {Evolution of Conspecific Brood Parasitism versus Cooperative Breeding as Alternative Reproductive Tactics.}, journal = {The American naturalist}, volume = {187}, number = {1}, pages = {35-47}, doi = {10.1086/684127}, pmid = {27277401}, issn = {1537-5323}, mesh = {Animals ; *Biological Evolution ; Birds/*physiology ; Female ; Models, Biological ; *Nesting Behavior ; Ovum/physiology ; Reproduction/physiology ; *Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {Cooperative breeding and conspecific brood parasitism can both be favored by ecological saturation of breeding territories or nest sites. Here, we develop a model that links these alternative reproductive tactics by focusing on nonnesting females (S) that either breed cooperatively with a nesting female (N) or parasitize a third, outside host female (H). We find that cooperative breeding is more likely to evolve with increasing relatedness of cooperating females (S or N) to the outside host female (H) and with increasing costs to the hosts for receiving parasitic eggs. Conversely, cooperation is less likely with increasing kinship between the two potentially cooperative nesters (S and N). This is because even the nesting female gains higher inclusive fitness as long as the number of parasitic eggs (of her otherwise potentially cooperating partner) is sufficiently high. We find the relationship between kinship and reproductive skew within cooperative nests can be either positive or negative depending on the fecundity of parasites versus nesting females. We also find that either of the cooperatively nesting females is more likely to tolerate a smaller fraction of group reproduction as kinship with the host female increases and as the host reproduces more (relative to the parasite) in outside nests. Finally, our model predicts that, as the outside option of conspecific brood parasitism becomes more profitable, helping behavior (zero reproduction by one female) is less likely to evolve in cooperatively breeding groups.}, } @article {pmid27270455, year = {2016}, author = {Dimitriu, T and Misevic, D and Lotton, C and Brown, SP and Lindner, AB and Taddei, F}, title = {Indirect Fitness Benefits Enable the Spread of Host Genes Promoting Costly Transfer of Beneficial Plasmids.}, journal = {PLoS biology}, volume = {14}, number = {6}, pages = {e1002478}, pmid = {27270455}, issn = {1545-7885}, mesh = {Algorithms ; Bacteria/*genetics ; Conjugation, Genetic ; Drug Resistance, Bacterial/*genetics ; Escherichia coli/genetics ; Evolution, Molecular ; *Gene Transfer, Horizontal ; Genes, Bacterial/*genetics ; Genetic Fitness ; Genetics, Population ; Interspersed Repetitive Sequences/genetics ; Models, Genetic ; Plasmids/genetics ; Selection, Genetic ; }, abstract = {Bacterial genes that confer crucial phenotypes, such as antibiotic resistance, can spread horizontally by residing on mobile genetic elements (MGEs). Although many mobile genes provide strong benefits to their hosts, the fitness consequences of the process of transfer itself are less clear. In previous studies, transfer has been interpreted as a parasitic trait of the MGEs because of its costs to the host but also as a trait benefiting host populations through the sharing of a common gene pool. Here, we show that costly donation is an altruistic act when it spreads beneficial MGEs favoured when it increases the inclusive fitness of donor ability alleles. We show mathematically that donor ability can be selected when relatedness at the locus modulating transfer is sufficiently high between donor and recipients, ensuring high frequency of transfer between cells sharing donor alleles. We further experimentally demonstrate that either population structure or discrimination in transfer can increase relatedness to a level selecting for chromosomal transfer alleles. Both mechanisms are likely to occur in natural environments. The simple process of strong dilution can create sufficient population structure to select for donor ability. Another mechanism observed in natural isolates, discrimination in transfer, can emerge through coselection of transfer and discrimination alleles. Our work shows that horizontal gene transfer in bacteria can be promoted by bacterial hosts themselves and not only by MGEs. In the longer term, the success of cells bearing beneficial MGEs combined with biased transfer leads to an association between high donor ability, discrimination, and mobile beneficial genes. However, in conditions that do not select for altruism, host bacteria promoting transfer are outcompeted by hosts with lower transfer rate, an aspect that could be relevant in the fight against the spread of antibiotic resistance.}, } @article {pmid27264438, year = {2016}, author = {Biernaskie, JM and Foster, KR}, title = {Ecology and multilevel selection explain aggression in spider colonies.}, journal = {Ecology letters}, volume = {19}, number = {8}, pages = {873-879}, pmid = {27264438}, issn = {1461-0248}, support = {242670/ERC_/European Research Council/International ; BB/M013995/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adaptation, Physiological ; *Aggression ; Animals ; *Ecosystem ; Models, Biological ; *Selection, Genetic ; *Social Behavior ; Spiders/*genetics/*physiology ; }, abstract = {Progress in sociobiology continues to be hindered by abstract debates over methodology and the relative importance of within-group vs. between-group selection. We need concrete biological examples to ground discussions in empirical data. Recent work argued that the levels of aggression in social spider colonies are explained by group-level adaptation. Here, we examine this conclusion using models that incorporate ecological detail while remaining consistent with kin- and multilevel selection frameworks. We show that although levels of aggression are driven, in part, by between-group selection, incorporating universal within-group competition provides a striking fit to the data that is inconsistent with pure group-level adaptation. Instead, our analyses suggest that aggression is favoured primarily as a selfish strategy to compete for resources, despite causing lower group foraging efficiency or higher risk of group extinction. We argue that sociobiology will benefit from a pluralistic approach and stronger links between ecologically informed models and data.}, } @article {pmid27263469, year = {2016}, author = {Viblanc, VA and Saraux, C and Murie, JO and Dobson, FS}, title = {Kin effects on energy allocation in group-living ground squirrels.}, journal = {The Journal of animal ecology}, volume = {85}, number = {5}, pages = {1361-1369}, doi = {10.1111/1365-2656.12541}, pmid = {27263469}, issn = {1365-2656}, mesh = {Alberta ; Animals ; *Energy Metabolism ; Female ; Genetic Fitness ; *Reproduction ; Sciuridae/genetics/*physiology ; *Territoriality ; }, abstract = {The social environment has potent effects on individual phenotype and fitness in group-living species. We asked whether the presence of kin might act on energy allocation, a central aspect of life-history variation. Using a 22-year data set on reproductive and somatic allocations in Columbian ground squirrels (Urocitellus columbianus), we tested the effects of co-breeding and non-breeding kin on the fitness and energy allocation balance between reproduction and personal body condition of individual females. Greater numbers of co-breeding kin had a positive effect on the number of offspring weaned, through the mechanism of altering energy allocation patterns. On average, females with higher numbers of co-breeding kin did not increase energy income but biased energy allocation towards reproduction. Co-breeding female kin ground squirrels maintain close nest burrows, likely providing a social buffer against territorial invasions from non-kin ground squirrels. Lower aggressiveness, lower risks of infanticide from female kin and greater protection of territorial boundaries may allow individual females to derive net fitness benefits via their energy allocation strategies. We demonstrated the importance of kin effects on a fundamental life-history trade-off.}, } @article {pmid27250600, year = {2016}, author = {Davies, NG and Ross, L and Gardner, A}, title = {The ecology of sex explains patterns of helping in arthropod societies.}, journal = {Ecology letters}, volume = {19}, number = {8}, pages = {862-872}, doi = {10.1111/ele.12621}, pmid = {27250600}, issn = {1461-0248}, mesh = {Adaptation, Physiological/*physiology ; Animals ; Arthropods/*genetics/*physiology ; Biological Evolution ; Female ; Male ; Models, Biological ; Selection, Genetic ; Sex Characteristics ; Sex Ratio ; *Social Behavior ; }, abstract = {Across arthropod societies, sib-rearing (e.g. nursing or nest defence) may be provided by females, by males or by both sexes. According to Hamilton's 'haplodiploidy hypothesis', this diversity reflects the relatedness consequences of diploid vs. haplodiploid inheritance. However, an alternative 'preadaptation hypothesis' instead emphasises an interplay of ecology and the co-option of ancestral, sexually dimorphic traits for sib-rearing. The preadaptation hypothesis has recently received empirical support, but remains to be formalised. Here, we mathematically model the coevolution of sex-specific helping and sex allocation, contrasting these hypotheses. We find that ploidy per se has little effect. Rather, the ecology of sex shapes patterns of helping: sex-specific preadaptation strongly influences who helps; a freely adjustable sex ratio magnifies sex biases and promotes helping; and sib-mating, promiscuity, and reproductive autonomy also modulate the sex and abundance of helpers. An empirical survey reveals that patterns of sex-specific helping in arthropod taxa are consistent with the preadaptation hypothesis.}, } @article {pmid27211350, year = {2016}, author = {Andrade, AC and Miranda, EA and Del Lama, MA and Nascimento, FS}, title = {Reproductive concessions between related and unrelated members promote eusociality in bees.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {26635}, pmid = {27211350}, issn = {2045-2322}, mesh = {Animals ; Bees/*physiology ; Behavior, Animal/*physiology ; Female ; Male ; Reproduction/physiology ; *Social Behavior ; }, abstract = {Animal societies exhibit remarkable variation in their breeding strategies. Individuals can maximize their fitness by either reproducing or by helping relatives. Social hymenopterans have been key taxa for the study of Hamilton's inclusive fitness theory because the haplodiploid sex-determination system results in asymmetric relatedness among breeders producing conflict over the partitioning of reproduction. In small cooperative groups of insects, totipotent individuals may maximize their inclusive fitness by controlling reproduction despotically rather than helping their relatives. Here, we demonstrate that the dominant females of the primitively eusocial bee Euglossa melanotricha (Apidae: Euglossini) control reproduction, but concede part of the reproductive output with their related and unrelated subordinates. As expected, a dominant female capitalizes on the direct reproduction of related subordinates, according to her interests. We found that reproductive skew was positively correlated with relatedness. The concessions were highly reduced in mother-daughter and sibling nests (relatedness r ± s.d. = 0.54 ± 0.02 and 0.79 ± 0.02, respectively) but much more egalitarian in unrelated associations (r = -0.10 ± 0.01). We concluded that reproductive skew in these primitively eusocial bees is strongly related to the genetic structure of associations, and also that females are able to assess pairwise relatedness, either directly or indirectly, and use this information to mediate social contracts.}, } @article {pmid27193460, year = {2016}, author = {Cassidy, KA and McIntyre, RT}, title = {Do gray wolves (Canis lupus) support pack mates during aggressive inter-pack interactions?.}, journal = {Animal cognition}, volume = {19}, number = {5}, pages = {939-947}, doi = {10.1007/s10071-016-0994-1}, pmid = {27193460}, issn = {1435-9456}, mesh = {*Aggression ; Altruism ; Animals ; *Territoriality ; *Wolves ; }, abstract = {For group-living mammals, social coordination increases success in everything from hunting and foraging (Crofoot and Wrangham in Mind the Gap, Springer, Berlin, 2010; Bailey et al. in Behav Ecol Sociobiol 67:1-17, 2013) to agonism (Mosser and Packer in Anim Behav 78:359-370, 2009; Wilson et al. in Anim Behav 83:277-291, 2012; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Cooperation is found in many species and, due to its low costs, likely is a determining factor in the evolution of living in social groups (Smith in Anim Behav 92:291-304, 2014). Beyond cooperation, many mammals perform costly behaviors for the benefit of group mates (e.g., parental care, food sharing, grooming). Altruism is considered the most extreme case of cooperation where the altruist increases the fitness of the recipient while decreasing its own fitness (Bell in Selection: the mechanism of evolution. Oxford University Press, Oxford 2008). Gray wolf life history requires intra-pack familiarity, communication, and cooperation in order to succeed in hunting (MacNulty et al. in Behav Ecol doi: 10.1093/beheco/arr159 2011) and protecting group resources (Stahler et al. in J Anim Ecol 82: 222-234, 2013; Cassidy et al. in Behav Ecol 26:1352-1360, 2015). Here, we report 121 territorial aggressive inter-pack interactions in Yellowstone National Park between 1 April 1995 and 1 April 2011 (>5300 days of observation) and examine each interaction where one wolf interferes when its pack mate is being attacked by a rival group. This behavior was recorded six times (17.6 % of interactions involving an attack) and often occurred between dyads of closely related individuals. We discuss this behavior as it relates to the evolution of cooperation, sociality, and altruism.}, } @article {pmid27191403, year = {2016}, author = {Kulik, L and Langos, D and Widdig, A}, title = {Mothers Make a Difference: Mothers Develop Weaker Bonds with Immature Sons than Daughters.}, journal = {PloS one}, volume = {11}, number = {5}, pages = {e0154845}, pmid = {27191403}, issn = {1932-6203}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Aggression ; Animals ; Animals, Newborn ; *Behavior, Animal ; Female ; Macaca mulatta ; Male ; *Maternal Behavior ; Sex Factors ; }, abstract = {Among mammals, individuals form strong social bonds preferentially with their kin. Differences in these relationships are linked to differential kin availability due to sex-specific dispersal patterns, but there is some indication that differential bonding among sexes already occurs prior to maturation. However, little is known about how these patterns arise during individual development. Here we investigated sex differences in the development of mother-offspring bonds in rhesus macaques (Macaca mulatta). Our results revealed that mothers showed sex-biased bonding toward their offspring. Sons had a distinctly higher probability of receiving aggression from their mothers than did daughters in the first year of life, while no differences were found with respect to affiliative interactions. After the first year, probabilities of all affiliative and aggressive behaviours investigated were higher for daughters than for sons, although generally declining. Furthermore, sons spending less time with their mother and receiving more maternal aggression tended to disperse earlier. The results of our study suggest that mothers influence their bonding strength with offspring by interacting less affiliative with sons than daughters.}, } @article {pmid27158472, year = {2016}, author = {Kramer, J and Meunier, J}, title = {Kin and multilevel selection in social evolution: a never-ending controversy?.}, journal = {F1000Research}, volume = {5}, number = {}, pages = {}, pmid = {27158472}, issn = {2046-1402}, abstract = {Kin selection and multilevel selection are two major frameworks in evolutionary biology that aim at explaining the evolution of social behaviors. However, the relationship between these two theories has been plagued by controversy for almost half a century and debates about their relevance and usefulness in explaining social evolution seem to rekindle at regular intervals. Here, we first provide a concise introduction into the kin selection and multilevel selection theories and shed light onto the roots of the controversy surrounding them. We then review two major aspects of the current debate: the presumed formal equivalency of the two theories and the question whether group selection can lead to group adaptation. We conclude by arguing that the two theories can offer complementary approaches to the study of social evolution: kin selection approaches usually focus on the identification of optimal phenotypes and thus on the endresult of a selection process, whereas multilevel selection approaches focus on the ongoing selection process itself. The two theories thus provide different perspectives that might be fruitfully combined to promote our understanding of the evolution in group-structured populations.}, } @article {pmid27121043, year = {2016}, author = {Birkemeyer, CS and Thomsen, R and Jänig, S and Kücklich, M and Slama, A and Weiß, BM and Widdig, A}, title = {Sampling the Body Odor of Primates: Cotton Swabs Sample Semivolatiles Rather Than Volatiles.}, journal = {Chemical senses}, volume = {41}, number = {6}, pages = {525-535}, pmid = {27121043}, issn = {1464-3553}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Animals ; Gas Chromatography-Mass Spectrometry ; Macaca mulatta ; Odorants/*analysis ; Volatile Organic Compounds/*analysis ; }, abstract = {We assessed the suitability of a frequently used sampling method employing cotton swabs for collecting animal body odor for gas chromatography-mass spectrometry (GC-MS) analysis of volatile organic compounds (VOCs). Our method validation showed that both sampling material and sampling protocols affect the outcome of the analyses. Thus, among the tested protocols swabs of pure viscose baked before use and extracted with hexane had the least blank interferences in GC-MS analysis. Most critical for the recovery of VOCs was the handling time: the significant recovery losses of volatiles experienced with this sampling procedure suggest that a rapid processing of such samples is required. In a second part, we used swab sampling to sample the body odor of rhesus macaques (Macaca mulatta), which lack scent glands. First results after GC-MS analysis of the samples collected from these nonhuman primates emphasize that proper analytical performance is an indispensable prerequisite for successful automated data evaluation of the complex GC-MS profiles. Moreover, the retention times and the nature of the identified chemical compounds in our samples suggest that the use of swabs is generally more appropriate for collecting semivolatile rather than VOCs.}, } @article {pmid27069620, year = {2015}, author = {Grimm, A and Weiß, BM and Kulik, L and Mihoub, JB and Mundry, R and Köppen, U and Brueckmann, T and Thomsen, R and Widdig, A}, title = {Earlier breeding, lower success: does the spatial scale of climatic conditions matter in a migratory passerine bird?.}, journal = {Ecology and evolution}, volume = {5}, number = {23}, pages = {5722-5734}, pmid = {27069620}, issn = {2045-7758}, abstract = {Following over 20 years of research on the climatic effects on biodiversity we now have strong evidence that climate change affects phenology, fitness, and distribution ranges of different taxa, including birds. Bird phenology likely responds to changes in local weather. It is also affected by climatic year-to-year variations on larger scales. Although such scale-related effects are common in ecology, most studies analyzing the effects of climate change were accomplished using climatic information on a single spatial scale. In this study, we aimed at determining the scale-dependent sensitivity of breeding phenology and success to climate change in a migratory passerine bird, the barn swallow (Hirundo rustica). For both annual broods, we investigated effects of local weather (local scale) and the North Atlantic Oscillation (NAO, large scale) on the timing of breeding and breeding success. Consistent with previous studies in migratory birds we found that barn swallows in Eastern Germany bred progressively earlier. At the same time, they showed reduced breeding success over time in response to recent climatic changes. Responses to climatic variation were observed on both local and large climatic scales, but they differed with respect to the ecological process considered. Specifically, we found that the timing of breeding was primarily influenced by large-scale NAO variations and to a lesser extent by local weather on the breeding grounds. Conversely, climatic conditions on the local scale affected breeding success, exclusively. The observed decrease in breeding success over years is likely a consequence of scale-related mismatches between climatic conditions during different breeding phases. This provides further evidence that a species' response of earlier breeding may not be enough to cope with climate change. Our results emphasize the importance of considering the response of ecological processes along different climatic scales in order to better understand the complexity of climate change effects on biodiversity.}, } @article {pmid27045365, year = {2016}, author = {Ketzis, JK and Fogarty, EA and Marttini, K and Bowman, DD}, title = {Explaining premunition with Kin selection using Haemonchus contortus.}, journal = {Parasitology}, volume = {143}, number = {9}, pages = {1187-1192}, doi = {10.1017/S0031182016000561}, pmid = {27045365}, issn = {1469-8161}, mesh = {Animals ; Female ; Haemonchiasis/immunology/parasitology/*veterinary ; Haemonchus/anatomy & histology/classification/*immunology ; Male ; Recurrence ; Sheep ; Sheep Diseases/*immunology/parasitology ; }, abstract = {Premunition is the state in a disease where an existing infection protects the host from reinfection with the same species. The cause of premunition is not clearly understood. In this study, we hypothesized that kin-selection might be a contributing factor in premunition. To test this theory, sheep were infected either once with a linguiform or smooth vulval morphotype of Haemonchos contortus, twice with the same morphotype or twice with different morphotypes. All infections resulted in a similar number of adult parasites. However, there were differences in the morphotypes recovered providing potential evidence of kin selection. Negative interference competition might also contribute to the reduction of the incoming population. Allelopathic or physical interactions between the parasites may be the mechanism behind the observed phenomena.}, } @article {pmid27028082, year = {2016}, author = {Rautiala, P and Gardner, A}, title = {Intragenomic Conflict over Soldier Allocation in Polyembryonic Parasitoid Wasps.}, journal = {The American naturalist}, volume = {187}, number = {4}, pages = {E106-15}, doi = {10.1086/685082}, pmid = {27028082}, issn = {1537-5323}, mesh = {Animals ; Biological Evolution ; Competitive Behavior ; Female ; *Genomic Imprinting ; Larva/genetics ; Male ; *Models, Genetic ; Sex Ratio ; Wasps/*genetics/growth & development ; }, abstract = {Understanding the selection pressures that have driven the evolution of sterile insect castes has been the focus of decades of intense scientific debate. An amenable empirical test bed for theory on this topic is provided by the sterile-soldier caste of polyembryonic parasitoid wasps. The function of these soldiers has been a source of controversy, with two basic hypotheses emerging: the "brood-benefit" hypothesis that they provide an overall benefit for their siblings and the "sex-ratio-conflict" hypothesis that the soldiers mediate a conflict between brothers and sisters by killing their opposite-sex siblings. Here, we investigate the divergent sex-ratio optima of a female embryo's maternal-origin and paternal-origin genes, to determine the potential for, and direction of, intragenomic conflict over soldiering. We then derive contrasting empirically testable predictions concerning the patterns of genomic imprinting that are expected to arise out of this intragenomic conflict, for the brood-benefit versus the sex-ratio-conflict hypothesis of soldier function.}, } @article {pmid27002224, year = {2016}, author = {Boothroyd, LG and Cross, CP}, title = {The impact of parenthood on physical aggression: Evidence from criminal data.}, journal = {Aggressive behavior}, volume = {42}, number = {6}, pages = {577-584}, doi = {10.1002/ab.21652}, pmid = {27002224}, issn = {1098-2337}, mesh = {Adult ; *Aggression ; Criminals/*statistics & numerical data ; Female ; Humans ; Male ; *Parents ; Sex Factors ; United States/epidemiology ; Violence/*statistics & numerical data ; }, abstract = {Evolutionary approaches to sex differences in physical aggression weigh the potential benefits of aggression against the likely costs to inclusive fitness, with some authors focusing on the damage physical injury would do to female inclusive fitness, and others on the extent to which success in physical competition may particularly enhance male fitness. This study tested a hypothesis derived from these approaches: that parents would be less physically aggressive than non-parents because of the damage any physical injury would do to their inclusive fitness. Analysis was carried out using the United States federal sentencing records for 1994-1999 (22,344 individuals). The proportion of theft convictions which were violent (robbery; vs. larceny) was significantly greater for men than women (odds ratio 7.7). As predicted, non-parents were significantly more likely to be violent than parents (odds ratio 1.6). Parenthood had a similar effect on relative rates of violence in men and women, although the baseline was considerably higher for men. There was also a significant effect in men of marital status, which interacted with parental status such that parenthood was only associated with a reduction in rates of violence in males recorded as partnered. The results are interpreted in terms of both evolutionary theory and recent work on the hormonal impacts of marriage and parenthood. Aggr. Behav. 42:577-584, 2016. © 2016 Wiley Periodicals, Inc.}, } @article {pmid26990199, year = {2016}, author = {Espinosa, A and Paz-Y-Miño-C, G and Hackey, M and Rutherford, S}, title = {Entamoeba Clone-Recognition Experiments: Morphometrics, Aggregative Behavior, and Cell-Signaling Characterization.}, journal = {The Journal of eukaryotic microbiology}, volume = {63}, number = {3}, pages = {384-393}, pmid = {26990199}, issn = {1550-7408}, support = {P20 GM103430/GM/NIGMS NIH HHS/United States ; }, mesh = {Actins/metabolism ; Animals ; Ankyrins/metabolism ; Biological Evolution ; Clone Cells/physiology ; Entamoeba/classification/*genetics/*physiology ; HSP70 Heat-Shock Proteins/metabolism ; Phylogeny ; Protein Kinases/metabolism ; *Signal Transduction ; }, abstract = {Studies on clone- and kin-discrimination in protists have proliferated during the past decade. We report clone-recognition experiments in seven Entamoeba lineages (E. invadens IP-1, E. invadens VK-1:NS, E. terrapinae, E. moshkovskii Laredo, E. moshkovskii Snake, E. histolytica HM-1:IMSS and E. dispar). First, we characterized morphometrically each clone (length, width, and cell-surface area) and documented how they differed statistically from one another (as per single-variable or canonical-discriminant analyses). Second, we demonstrated that amebas themselves could discriminate self (clone) from different (themselves vs. other clones). In mix-cell-line cultures between closely-related (E. invadens IP-1 vs. E. invadens VK-1:NS) or distant-phylogenetic clones (E. terrapinae vs. E. moshkovskii Laredo), amebas consistently aggregated with same-clone members. Third, we identified six putative cell-signals secreted by the amebas (RasGap/Ankyrin, coronin-WD40, actin, protein kinases, heat shock 70, and ubiquitin) and which known functions in Entamoeba spp. included: cell proliferation, cell adhesion, cell movement, and stress-induced encystation. To our knowledge, this is the first multi-clone characterization of Entamoeba spp. morphometrics, aggregative behavior, and cell-signaling secretion in the context of clone-recognition. Protists allow us to study cell-cell recognition from ecological and evolutionary perspectives. Modern protistan lineages can be central to studies about the origins and evolution of multicellularity.}, } @article {pmid26969266, year = {2016}, author = {Wolf, JB and Wade, MJ}, title = {Evolutionary genetics of maternal effects.}, journal = {Evolution; international journal of organic evolution}, volume = {70}, number = {4}, pages = {827-839}, pmid = {26969266}, issn = {1558-5646}, support = {R01 GM65414-04A1/GM/NIGMS NIH HHS/United States ; BB/C516936/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; R01 GM084238/GM/NIGMS NIH HHS/United States ; R01 GM065414/GM/NIGMS NIH HHS/United States ; R01GM084238-07/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; Gene Frequency ; Genetic Variation ; Genotype ; Inbreeding ; *Inheritance Patterns ; *Models, Genetic ; Phenotype ; }, abstract = {Maternal genetic effects (MGEs), where genes expressed by mothers affect the phenotype of their offspring, are important sources of phenotypic diversity in a myriad of organisms. We use a single-locus model to examine how MGEs contribute patterns of heritable and nonheritable variation and influence evolutionary dynamics in randomly mating and inbreeding populations. We elucidate the influence of MGEs by examining the offspring genotype-phenotype relationship, which determines how MGEs affect evolutionary dynamics in response to selection on offspring phenotypes. This approach reveals important results that are not apparent from classic quantitative genetic treatments of MGEs. We show that additive and dominance MGEs make different contributions to evolutionary dynamics and patterns of variation, which are differentially affected by inbreeding. Dominance MGEs make the offspring genotype-phenotype relationship frequency dependent, resulting in the appearance of negative frequency-dependent selection, while additive MGEs contribute a component of parent-of-origin dependent variation. Inbreeding amplifies the contribution of MGEs to the additive genetic variance and, therefore enhances their evolutionary response. Considering evolutionary dynamics of allele frequency change on an adaptive landscape, we show that this landscape differs from the mean fitness surface, and therefore, under some condition, fitness peaks can exist but not be "available" to the evolving population.}, } @article {pmid26968909, year = {2016}, author = {Loffler, G}, title = {Subsistence-patterns, gender roles, effective temperature, and the evolutionary timing of a post reproductive life span.}, journal = {Medical hypotheses}, volume = {89}, number = {}, pages = {48-57}, doi = {10.1016/j.mehy.2016.01.020}, pmid = {26968909}, issn = {1532-2777}, mesh = {Aging/genetics ; Agriculture ; Animals ; *Biological Evolution ; Body Temperature/*genetics ; Female ; *Gender Identity ; Humans ; Longevity/*genetics ; Male ; Menopause/*genetics ; Reproduction/*physiology ; Selection, Genetic/genetics ; Sex Factors ; }, abstract = {Evolutionary anthropologists explain menopause and the start of a post reproductive lifespan (PRLS), as beneficiary for older women who can now help contribute to their children/grandchildren's wellbeing. This paper presents a new model with the aim to elucidate when, where, and for whom, such benefits may have arisen. In foraging societies, women contribute nutrients to their social groups/family units to a greater degree as overall effective temperatures (ETs) rise. Where the ET is favorable for women's contributions (ETs between 15 and 20), selection does lengthen the PRLS of women because women contribute sufficiently to enhance their own inclusive fitness. Paleo-environment records suggest that the climate necessary to encourage an increase PRLS occurred shortly after the younger dryad in emerging subtropical settings. Subsistence patterns and gender roles may have played a role in the evolution of PRLS in human females.}, } @article {pmid26947271, year = {2016}, author = {Taylor, P}, title = {Hamilton׳s Rule in finite populations with synergistic interactions.}, journal = {Journal of theoretical biology}, volume = {397}, number = {}, pages = {151-157}, doi = {10.1016/j.jtbi.2016.02.034}, pmid = {26947271}, issn = {1095-8541}, mesh = {*Algorithms ; Animals ; *Epistasis, Genetic ; Evolution, Molecular ; Game Theory ; Genetic Fitness ; Genetics, Population ; Humans ; *Interpersonal Relations ; *Models, Genetic ; Mutation ; *Selection, Genetic ; }, abstract = {Much debate has appeared in the literature over the generality of the inclusive fitness approach in the modeling of evolutionary behavior. Here I focus on the capacity of the inclusive fitness approach to effectively handle non-additive or synergistic interactions. I work with a binary interaction with the matrix game [abcd] and I restrict attention to transitive (homogeneous) populations with weak selective effects. First of all I observe that the construction of "higher-order" relatedness coefficients permits these synergistic interactions to be analyzed with an inclusive fitness analysis. These coefficients are an immediate generalization of Hamilton׳s original coefficient and can be calculated with exactly the same type of recursive equations. Secondly I observe that for models in which the population is not too large and local genetic renewal is rare (e,g, rare mutation), these higher order coefficients are not needed even with non-additive interactions; in fact the synergistic interaction is entirely equivalent to a closely-related additive one. The overall conclusion is that in the study of synergistic binary social interactions (2-player games) in a finite homogeneous population with weak selection and rare genetic renewal, a standard inclusive-fitness analysis is able to predict the direction of allele-frequency change. I apply this result to analyze a recent model of Allen and Nowak (2015).}, } @article {pmid26933219, year = {2016}, author = {Springer, SA and Schwarz, F and Altheide, TK and Varki, NM and Varki, A and Gagneux, P}, title = {Reply to Liu and Jiang: Maintenance of postreproductive cognitive capacity by inclusive fitness.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {12}, pages = {E1591-2}, pmid = {26933219}, issn = {1091-6490}, support = {P01 HL107150/HL/NHLBI NIH HHS/United States ; R01 GM095882/GM/NIGMS NIH HHS/United States ; }, mesh = {Alzheimer Disease/*genetics ; Animals ; Brain/*physiopathology ; Cognition Disorders/*genetics ; *Genetic Fitness ; Humans ; Sialic Acid Binding Ig-like Lectin 3/*physiology ; }, } @article {pmid26931797, year = {2016}, author = {Smith, J and Strassmann, JE and Queller, DC}, title = {Fine-scale spatial ecology drives kin selection relatedness among cooperating amoebae.}, journal = {Evolution; international journal of organic evolution}, volume = {70}, number = {4}, pages = {848-859}, doi = {10.1111/evo.12895}, pmid = {26931797}, issn = {1558-5646}, mesh = {Dictyostelium/*genetics/physiology ; Ecology ; Genotype ; *Microbial Interactions ; Population Density ; *Selection, Genetic ; Soil Microbiology ; }, abstract = {Cooperation among microbes is important for traits as diverse as antibiotic resistance, pathogen virulence, and sporulation. The evolutionary stability of cooperation against "cheater" mutants depends critically on the extent to which microbes interact with genetically similar individuals. The causes of this genetic social structure in natural microbial systems, however, are unknown. Here, we show that social structure among cooperative Dictyostelium amoebae is driven by the population ecology of colonization, growth, and dispersal acting at spatial scales as small as fruiting bodies themselves. Despite the fact that amoebae disperse while grazing, all it takes to create substantial genetic clonality within multicellular fruiting bodies is a few millimeters distance between the cells colonizing a feeding site. Even adjacent fruiting bodies can consist of different genotypes. Soil populations of amoebae are sparse and patchily distributed at millimeter scales. The fine-scale spatial structure of cells and genotypes can thus account for the otherwise unexplained high genetic uniformity of spores in fruiting bodies from natural substrates. These results show how a full understanding of microbial cooperation requires understanding ecology and social structure at the small spatial scales microbes themselves experience.}, } @article {pmid26924280, year = {2016}, author = {Wibowo, E and Johnson, TW and Wassersug, RJ}, title = {Infertility, impotence, and emasculation--psychosocial contexts for abandoning reproduction.}, journal = {Asian journal of andrology}, volume = {18}, number = {3}, pages = {403-408}, pmid = {26924280}, issn = {1745-7262}, mesh = {*Choice Behavior ; Erectile Dysfunction/*psychology ; Female ; Gender Dysphoria/*psychology/therapy ; Homosexuality, Male/*psychology ; Humans ; Infertility, Male/*psychology ; Male ; Masculinity ; Prostatic Neoplasms/psychology/therapy ; Reproductive Behavior/*psychology ; Sex Reassignment Surgery/*psychology ; Stress, Psychological/*psychology ; Testicular Neoplasms/psychology/therapy ; Transgender Persons ; Vasectomy/psychology ; }, abstract = {From a Darwinian perspective we live to reproduce, but in various situations genetic males elect not to reproduce by choosing medical treatments leading to infertility, impotence, and, in the extreme, emasculation. For many men, infertility can be psychologically distressing. However, for certain genetic males, being infertile may improve their quality of life. Examples include (1) men who seek vasectomy, (2) individuals with Gender Dysphoria (e.g., transwomen, and modern day voluntary eunuchs), (3) most gay men, and (4) men treated for testicular and prostate cancer. Men who desire vasectomy typically have a Darwinian fitness W >1 at the time of their vasectomies; i.e., after they have their desired number of offspring or consider themselves past an age for parenting newborns. In contrast, prostate and testicular cancer patients, along with individuals with extreme Gender Dysphoria, do not necessarily seek to be sterile, but accept it as an unavoidable consequence of the treatment for their condition undertaken for survival (in case of cancer patients) or to achieve a better quality of life (for those with Gender Dysphoria). Most gay men do not father children, but they may play an avuncular role, providing for their siblings' offspring's welfare, thus improving their inclusive fitness through kin selection. In a strictly Darwinian model, the primary motivation for all individuals is to reproduce, but there are many situations for men to remove themselves from the breeding populations because they have achieved a fitness W ≥1, or have stronger medical or psychological needs that preclude remaining fertile.}, } @article {pmid26909677, year = {2016}, author = {Strassmann, JE}, title = {Kin Discrimination in Dictyostelium Social Amoebae.}, journal = {The Journal of eukaryotic microbiology}, volume = {63}, number = {3}, pages = {378-383}, doi = {10.1111/jeu.12307}, pmid = {26909677}, issn = {1550-7408}, mesh = {Amoeba/genetics/*physiology ; Animals ; Biological Evolution ; Cell Adhesion/genetics ; Cell Movement ; Dictyostelium/*genetics/*physiology ; Fruiting Bodies, Fungal/genetics ; Protozoan Proteins/genetics ; }, abstract = {Evolved cooperation is stable only when the benefactor is compensated, either directly or through its relatives. Social amoebae cooperate by forming a mobile multicellular body in which, about 20% of participants ultimately die to form a stalk. This benefits the remaining individuals that become hardy spores at the top of the stalk, together making up the fruiting body. In studied species with stalked migration, P. violaceum, D. purpureum, and D. giganteum, sorting based on clone identity occurs in laboratory mixes, maintaining high relatedness within the fruiting bodies. D. discoideum has unstalked migration, where cell fate is not fixed until the slug forms a fruiting body. Laboratory mixes show some degree of both spatial and genotype-based sorting, yet most laboratory fruiting bodies remain chimeric. However, wild fruiting bodies are made up mostly of clonemates. A genetic mechanism for sorting is likely to be cell adhesion genes tgrB1 and tgrC1, which bind to each other. They are highly variable, as expected for a kin discrimination gene. It is a puzzle that these genes do not cause stronger discrimination between mixed wild clones, but laboratory conditions or strong sorting early in the social stage diminished by later slug fusion could be explanations.}, } @article {pmid26890431, year = {2016}, author = {Städele, V and Pines, M and Swedell, L and Vigilant, L}, title = {The ties that bind: Maternal kin bias in a multilevel primate society despite natal dispersal by both sexes.}, journal = {American journal of primatology}, volume = {78}, number = {7}, pages = {731-744}, doi = {10.1002/ajp.22537}, pmid = {26890431}, issn = {1098-2345}, mesh = {Animals ; Family ; Female ; Male ; *Microsatellite Repeats ; *Papio hamadryas ; Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {In many social animals, individuals derive fitness benefits from close social bonds, which are often formed among kin of the philopatric sex. Hamadryas baboons, however, exhibit a hierarchical, multilevel social system where both sexes disperse from their natal one-male-unit (OMU). Although this would seem to hinder maintenance of kin ties, both sexes appear largely philopatric at the higher order band and clan levels, possibly allowing for bonds with same sex kin by both males and females. In order to investigate the possibility of kin bonds in hamadryas baboons, we identified kin dyads in a band without known pedigree information using a large panel of genetic markers: 1 Y-linked, 4 X-linked, and 23 autosomal microsatellites and part of the mitochondrial hypervariable region I. With these data, we performed a kinship analysis while accounting for misclassification rates through simulations and determined kinship among two types of dyads: leader and follower males and female dyads within OMUs. Leader and follower males were maternal relatives more often than expected by chance, suggesting that kinship plays a role in the formation of these relationships. Moreover, maternal female relatives were found in the same OMU more often than expected by chance, indicating that females may be motivated to maintain post-dispersal contact with maternal female kin. Our results suggest that hamadryas baboons can recognize maternal kin and that kin selection has contributed to shaping their complex social system. This implies that an ancestral maternal kin bias has been retained in hamadryas society. Am. J. Primatol. 78:731-744, 2016. © 2016 Wiley Periodicals, Inc.}, } @article {pmid26888915, year = {2016}, author = {Nichols, HJ and Zecherle, L and Arbuckle, K}, title = {Patterns of philopatry and longevity contribute to the evolution of post-reproductive lifespan in mammals.}, journal = {Biology letters}, volume = {12}, number = {2}, pages = {20150992}, pmid = {26888915}, issn = {1744-957X}, mesh = {Animals ; *Biological Evolution ; Female ; *Homing Behavior ; *Longevity ; Male ; Mammals/*physiology ; Reproduction ; }, abstract = {While menopause has long been known as a characteristic trait of human reproduction, evidence for post-reproductive lifespan (PRLS) has recently been found in other mammals. Adaptive and non-adaptive hypotheses have been proposed to explain the evolution of PRLS, but formal tests of these are rare. We use a phylogenetic approach to evaluate hypotheses for the evolution of PRLS among mammals. In contrast to theoretical models predicting that PRLS may be promoted by male philopatry (which increases relatedness between a female and her group in old age), we find little evidence that male philopatry led to the evolution of a post-reproductive period. However, the proportion of life spent post-reproductive was related to lifespan and patterns of philopatry, suggesting that the duration of PRLS may be impacted by both non-adaptive and adaptive processes. Finally, the proportion of females experiencing PRLS was higher in species with male philopaty and larger groups, in accordance with adaptive models of PRLS. We suggest that the origin of PRLS primarily follows the non-adaptive 'mismatch' scenario, but that patterns of philopatry may subsequently confer adaptive benefits of late-life helping.}, } @article {pmid26873616, year = {2016}, author = {Paz-Y-Miño-C, G and Espinosa, A}, title = {Kin Discrimination in Protists: From Many Cells to Single Cells and Backwards.}, journal = {The Journal of eukaryotic microbiology}, volume = {63}, number = {3}, pages = {367-377}, pmid = {26873616}, issn = {1550-7408}, support = {P20 GM103430/GM/NIGMS NIH HHS/United States ; }, mesh = {Alleles ; Animals ; Biological Evolution ; Eukaryota/*classification/*genetics/physiology ; Genetic Fitness ; Phenotype ; }, abstract = {During four decades (1960-1990s), the conceptualization and experimental design of studies in kin recognition relied on work with multicellular eukaryotes, particularly Unikonta (including invertebrates and vertebrates) and some Bikonta (including plants). This pioneering research had an animal behavior approach. During the 2000s, work on taxa-, clone- and kin-discrimination and recognition in protists produced genetic and molecular evidence that unicellular organisms (e.g. Saccharomyces, Dictyostelium, Polysphondylium, Tetrahymena, Entamoeba and Plasmodium) could distinguish between same (self or clone) and different (diverse clones), as well as among conspecifics of close or distant genetic relatedness. Here, we discuss some of the research on the genetics of kin discrimination/recognition and highlight the scientific progress made by switching emphasis from investigating multicellular to unicellular systems (and backwards). We document how studies with protists are helping us to understand the microscopic, cellular origins and evolution of the mechanisms of kin discrimination/recognition and their significance for the advent of multicellularity. We emphasize that because protists are among the most ancient organisms on Earth, belong to multiple taxonomic groups and occupy all environments, they can be central to reexamining traditional hypotheses in the field of kin recognition, reformulating concepts, and generating new knowledge.}, } @article {pmid26873305, year = {2016}, author = {Metzler, D and Jordan, F and Pamminger, T and Foitzik, S}, title = {The influence of space and time on the evolution of altruistic defence: the case of ant slave rebellion.}, journal = {Journal of evolutionary biology}, volume = {29}, number = {5}, pages = {874-886}, doi = {10.1111/jeb.12846}, pmid = {26873305}, issn = {1420-9101}, mesh = {*Altruism ; Animals ; *Ants ; Computer Simulation ; *Host-Parasite Interactions ; Social Behavior ; }, abstract = {How can antiparasite defence traits evolve even if they do not directly benefit their carriers? An example of such an indirect defence is rebellion of enslaved Temnothorax longispinosus ant workers against their social parasite Temnothorax americanus, a slavemaking ant. Ant slaves have been observed to kill their oppressors' offspring, a behaviour from which the sterile slaves cannot profit directly. Parasite brood killing could, however, reduce raiding pressure on related host colonies nearby. We analyse with extensive computer simulations for the Temnothorax slavemaker system under what conditions a hypothetical rebel allele could invade a host population, and in particular, how host-parasite dynamics and population structure influence the rebel allele's success. Exploring a wide range of model parameters, we only found a small number of parameter combinations for which kin selection or multilevel selection could allow a slave rebellion allele to spread in the host population. Furthermore, we did not detect any cases in which the reduction of raiding pressure in the close vicinity of the slavemaker nest would substantially contribute to the inclusive fitness of rebels. This suggests that slave rebellion is not costly and perhaps a side-effect of some other beneficial trait. In some of our simulations, however, even a costly rebellion allele could spread in the population. This was possible when host-parasite interactions led to a metapopulation dynamic with frequent local extinctions and recolonizations of demes by the offspring of few immigrants.}, } @article {pmid26872896, year = {2016}, author = {Dunham, NT and Opere, PO}, title = {A unique case of extra-group infant adoption in free-ranging Angola black and white colobus monkeys (Colobus angolensis palliatus).}, journal = {Primates; journal of primatology}, volume = {57}, number = {2}, pages = {187-194}, pmid = {26872896}, issn = {1610-7365}, mesh = {Animals ; Colobus/*physiology ; Female ; Kenya ; *Maternal Behavior ; Mothers ; Social Behavior ; }, abstract = {Infant adoption has been reported in a variety of primate taxa both in captive and natural settings. Adoption by females may be adaptive by increasing inclusive fitness via shared genes between adoptive mother and adoptee or by providing valuable maternal practice which, in turn, may increase the female's future reproductive success. Others have argued that adoption may be non-adaptive and the result of a general attraction toward infants. Our study examines a unique case of adoption by an adult female Angola black and white colobus monkey (Colobus angolensis palliatus) who adopted an extra-group infant alongside her own biological infant. We compare infant behaviors and mother-infant interactions between biological infant and adoptee and then compare both biological infant and adoptee behavioral profiles to those of infants under normal circumstances. Data were collected from July 2014 to June 2015 on three habituated groups in the Diani Forest of Kenya. Scan sampling and pooled data were used to create daily and monthly behavioral profiles for the biological infant and adoptee, as well as a mean monthly profile of four infants under normal circumstances. Data include time spent (1) clinging to mother/adoptive mother, (2) clinging to another individual, (3) behaving independently, and (4) behaving in close proximity to mother/adoptive mother. Initially, the adoptee struggled to achieve behavioral profiles consistent with those of the biological infant and normal colobus infants of the same age as he spent significantly more time moving independently and significantly less time clinging to the adoptive mother. After the mysterious death of the biological infant in mid-January 2015, the adoptee assumed a behavioral profile similar to that of infants under normal conditions. This case does not support adaptive hypotheses for adoption (i.e., inclusive fitness or learning to mother). Instead, because the biological infant died, possibly due to the presence of the adoptee, we argue that this case of infant adoption was non-adaptive. Ultimately, this adoption appears to have been an outcome of the adoptee's persistent desire to be cared for and the female's strong propensity to engage in allomaternal behavior.}, } @article {pmid26854078, year = {2016}, author = {Nax, HH and Rigos, A}, title = {Assortativity evolving from social dilemmas.}, journal = {Journal of theoretical biology}, volume = {395}, number = {}, pages = {194-203}, doi = {10.1016/j.jtbi.2016.01.032}, pmid = {26854078}, issn = {1095-8541}, mesh = {Humans ; *Models, Theoretical ; *Social Behavior ; *Social Support ; }, abstract = {Assortative mechanisms can overcome tragedies of the commons that otherwise result in dilemma situations. Assortativity criteria include various forms of kin selection, greenbeard genes, and reciprocal behaviors, usually presuming an exogenously fixed matching mechanism. Here, we endogenize the matching process with the aim of investigating how assortativity itself, jointly with cooperation, is driven by evolution. Our main finding is that full-or-null assortativities turn out to be long-run stable in most cases, independent of the relative speeds of both processes. The exact incentive structure of the underlying social dilemma matters crucially. The resulting social loss is evaluated for general classes of dilemma games, thus quantifying to what extent the tragedy of the commons may be endogenously overcome.}, } @article {pmid26815856, year = {2016}, author = {Sargeant, EJ and Wikberg, EC and Kawamura, S and Jack, KM and Fedigan, LM}, title = {Paternal kin recognition and infant care in white-faced capuchins (Cebus capucinus).}, journal = {American journal of primatology}, volume = {78}, number = {6}, pages = {659-668}, doi = {10.1002/ajp.22530}, pmid = {26815856}, issn = {1098-2345}, mesh = {Animals ; *Behavior, Animal ; *Cebus ; Costa Rica ; Female ; Male ; Philippines ; Recognition, Psychology ; }, abstract = {Evidence for paternal kin recognition and paternally biased behaviors is mixed among primates. We investigate whether infant handling behaviors exhibit paternal kin biases in wild white-faced capuchins monkeys (Cebus capucinus) by comparing interactions between infants and genetic sires, potential sires, siblings (full sibling, maternal, and paternal half-siblings) and unrelated handlers. We used a linear mixed model approach to analyze data collected on 21 focal infants from six groups in Sector Santa Rosa, Costa Rica. Our analyses suggest that the best predictor of adult and subadult male interactions with an infant is the male's dominance status, not his paternity status. We found that maternal siblings but not paternal siblings handled infants more than did unrelated individuals. We conclude that maternal but not paternal kinship influence patterns of infant handling in white-faced capuchins, regardless of whether or not they can recognize paternal kin. Am. J. Primatol. 78:659-668, 2016. © 2016 Wiley Periodicals, Inc.}, } @article {pmid26811773, year = {2016}, author = {Gerber, L and Krützen, M and de Ruiter, JR and van Schaik, CP and van Noordwijk, MA}, title = {Postdispersal nepotism in male long-tailed macaques (Macaca fascicularis).}, journal = {Ecology and evolution}, volume = {6}, number = {1}, pages = {46-55}, pmid = {26811773}, issn = {2045-7758}, abstract = {Cooperative behaviors are promoted by kin selection if the costs to the actor are smaller than the fitness benefits to the recipient, weighted by the coefficient of relatedness. In primates, cooperation occurs primarily among female dyads. Due to male dispersal before sexual maturity in many primate species, however, it is unknown whether there are sufficient opportunities for selective tolerance and occasional coalitionary support for kin selection to favor male nepotistic support. We studied the effect of the presence of male kin on correlates of male reproductive success (residence time, duration of high dominance rank) in non-natal male long-tailed macaques (Macaca fascicularis). We found that "related" (i.e., related at the half-sibling level or higher) males in a group have a significantly higher probability to remain in the non-natal group compared to males without relatives. Moreover, males stayed longer in a group when a relative was present at group entry or joined the same group within 3 months upon arrival. Males with co-residing relatives also maintained a high rank for longer than those without. To our knowledge, this is the first demonstration of a potential nepotistic effect on residence and rank maintenance among non-natal males in a social system without long-term alliances.}, } @article {pmid26787913, year = {2016}, author = {Pollak, S and Omer-Bendori, S and Even-Tov, E and Lipsman, V and Bareia, T and Ben-Zion, I and Eldar, A}, title = {Facultative cheating supports the coexistence of diverse quorum-sensing alleles.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {8}, pages = {2152-2157}, pmid = {26787913}, issn = {1091-6490}, mesh = {Alleles ; Bacillus subtilis/*genetics/*physiology ; Biological Evolution ; Genes, Bacterial ; Genetic Variation ; *Models, Biological ; Models, Genetic ; Mutation ; Quorum Sensing/*genetics/physiology ; }, abstract = {Bacterial quorum sensing enables bacteria to cooperate in a density-dependent manner via the group-wide secretion and detection of specific autoinducer molecules. Many bacterial species show high intraspecific diversity of autoinducer-receptor alleles, called pherotypes. The autoinducer produced by one pherotype activates its coencoded receptor, but not the receptor of another pherotype. It is unclear what selection forces drive the maintenance of pherotype diversity. Here, we use the ComQXPA system of Bacillus subtilis as a model system, to show that pherotype diversity can be maintained by facultative cheating--a minority pherotype exploits the majority, but resumes cooperation when its frequency increases. We find that the maintenance of multiple pherotypes by facultative cheating can persist under kin-selection conditions that select against "obligate cheaters" quorum-sensing response null mutants. Our results therefore support a role for facultative cheating and kin selection in the evolution of quorum-sensing diversity.}, } @article {pmid26774729, year = {2016}, author = {Mandel, R and Whay, HR and Klement, E and Nicol, CJ}, title = {Invited review: Environmental enrichment of dairy cows and calves in indoor housing.}, journal = {Journal of dairy science}, volume = {99}, number = {3}, pages = {1695-1715}, doi = {10.3168/jds.2015-9875}, pmid = {26774729}, issn = {1525-3198}, mesh = {Animal Husbandry ; Animal Welfare ; Animals ; Cattle/*physiology ; Dairying/*methods ; Female ; *Housing, Animal ; }, abstract = {In recent years, an increasing number of farmers are choosing to keep their cows indoors throughout the year. Indoor housing of cows allows farmers to provide high-yielding individuals with a nutritionally balanced diet fit for their needs, and it has important welfare benefits for both cows and their calves, such as protection from predators, parasites, and exposure to extreme weather conditions. However, it also confronts cows and calves with a wide range of environmental challenges. These include abiotic environmental sources of stress (e.g., exposure to loud and aversive sound) and confinement-specific stressors (e.g., restricted movement and maintenance in abnormal social groups). Cows and calves that live indoors are also faced with the challenge of occupying long periods with a limited range of possible behavioral patterns. Environmental enrichment can improve biological functioning (measured as increased lifetime reproductive success, increased inclusive fitness, or a correlate of these such as improved health), help animals to cope with stressors in their surroundings, reduce frustration, increase the fulfillment of behavioral needs, and promote more positive affective states. Here, we review recent findings on the effect of social, occupational, physical, sensory, and nutritional enrichment on dairy cows and calves, and we assess the appropriateness and practicality of implementing different enrichment practices on commercial dairy farms. Some of the enrichment methods reviewed here may also be applied to those more extensive cattle-raising systems, where similar challenges occur.}, } @article {pmid26755583, year = {2016}, author = {Galbraith, DA and Kocher, SD and Glenn, T and Albert, I and Hunt, GJ and Strassmann, JE and Queller, DC and Grozinger, CM}, title = {Testing the kinship theory of intragenomic conflict in honey bees (Apis mellifera).}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {4}, pages = {1020-1025}, pmid = {26755583}, issn = {1091-6490}, mesh = {Animals ; Bees/*genetics/physiology ; Crosses, Genetic ; DNA Methylation ; Family ; Female ; Male ; Polymorphism, Single Nucleotide ; Reproduction ; }, abstract = {Sexual reproduction brings genes from two parents (matrigenes and patrigenes) together into one individual. These genes, despite being unrelated, should show nearly perfect cooperation because each gains equally through the production of offspring. However, an individual's matrigenes and patrigenes can have different probabilities of being present in other relatives, so kin selection could act on them differently. Such intragenomic conflict could be implemented by partial or complete silencing (imprinting) of an allele by one of the parents. Evidence supporting this theory is seen in offspring-mother interactions, with patrigenes favoring acquisition of more of the mother's resources if some of the costs fall on half-siblings who do not share the patrigene. The kinship theory of intragenomic conflict is little tested in other contexts, but it predicts that matrigene-patrigene conflict may be rife in social insects. We tested the hypothesis that honey bee worker reproduction is promoted more by patrigenes than matrigenes by comparing across nine reciprocal crosses of two distinct genetic stocks. As predicted, hybrid workers show reproductive trait characteristics of their paternal stock, (indicating enhanced activity of the patrigenes on these traits), greater patrigenic than matrigenic expression, and significantly increased patrigenic-biased expression in reproductive workers. These results support both the general prediction that matrigene-patrigene conflict occurs in social insects and the specific prediction that honey bee worker reproduction is driven more by patrigenes. The success of these predictions suggests that intragenomic conflict may occur in many contexts where matrigenes and patrigenes have different relatednesses to affected kin.}, } @article {pmid26752766, year = {2016}, author = {Vasey, PL and VanderLaan, DP and Hames, R and Jaidee, A}, title = {A Problematic Test of the Kin Selection Hypothesis Among the Urak-Lawoi of Ko Lipe, Thailand: Commentary on Camperio Ciani, Battaglia, and Liotta (2015).}, journal = {Journal of sex research}, volume = {53}, number = {2}, pages = {149-152}, doi = {10.1080/00224499.2015.1115808}, pmid = {26752766}, issn = {1559-8519}, mesh = {*Biological Evolution ; Humans ; Thailand ; }, abstract = {Camperio Ciani et al. argued that the Urak-Lawoi people of Ko Lipe island live in a "traditional," "subsistence primitive society" reminiscent of the "ancestral" human past and that their socio-cultural situation is "remarkably similar" to Samoa. On this basis, they asserted that the Ko Lipe Urak-Lawoi are an appropriate population for determining the role that kin selection played in the evolution of male androphilia. The purpose of this commentary is to outline some of our concerns with this characterization and with the statistical analyses conducted by Camperio Ciani et al. in their study of the Urak-Lawoi.}, } @article {pmid26752608, year = {2016}, author = {Camperio Ciani, AS and Battaglia, U and Liotta, M}, title = {Response: Avuncularity and Kin Selection in Homosexuals: A Problematic Test or a Problematic Hypothesis?.}, journal = {Journal of sex research}, volume = {53}, number = {2}, pages = {153-156}, doi = {10.1080/00224499.2015.1115809}, pmid = {26752608}, issn = {1559-8519}, mesh = {*Homosexuality, Male ; Humans ; Male ; *Sexual Behavior ; }, abstract = {Here we respond to Vasey et al.'s critical comments regarding our article, "Societal norms rather than sexual orientation influence kin altruism and avuncularity in tribal Urak-Lawoi, Italian, and Spanish adult males" (Camperio Ciani, Battaglia, & Liotta, 2015 , JSR doi:10.1080/00224499.2014.993748). The first regards the selection of the Urak-Lawoi population of Ko Lipeh, which is considered too modern and touristic to be adequate to test the kin selection and avuncular hypothesis for homosexuality. We provide historical evidence of the contrary, and show that the population at the inception of our 10 years research was indeed primitive and tribal, and probands actually grew and lived in such a society. Only a few years after the 2004 tsunami, the island was developed and invaded by mass tourism. The second comment regarded the statistical analysis and interpretation of data. We show that we consistently and conservatively considered the effects of all confounding variables, both with comparative tests, and by a series of multivariate regression analyses. This was the orthodox procedure approved by all other reviewers. In conclusion, even addressing these comments, we maintain that the kin selection and avuncularity hypothesis for homosexuality is not supported by empirical data even in this primitive and tribal society.}, } @article {pmid26739375, year = {2016}, author = {Kisdi, E}, title = {Dispersal polymorphism in stable habitats.}, journal = {Journal of theoretical biology}, volume = {392}, number = {}, pages = {69-82}, doi = {10.1016/j.jtbi.2015.12.006}, pmid = {26739375}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Ecosystem ; *Models, Biological ; }, abstract = {In fragmented but temporally stable landscapes, kin competition selects for dispersal when habitat patches are small, whereas the loss of dispersal is favoured when dispersal is costly and local populations are large enough for kin interactions to be negligible. In heterogeneous landscapes with both small and large patches, contrasting levels of kin competition facilitate the coexistence of low-dispersal and high-dispersal strategies. In this paper, I use both adaptive dynamics and inclusive fitness to analyse the evolution of dispersal in a simple model assuming that each patch supports either a single individual or a large population. With this assumption, many results can be obtained analytically. If the fraction of individuals living in small patches is below a threshold, then evolutionary branching yields two coexisting dispersal strategies. An attracting and evolutionarily stable dimorphism always exists (also when the monomorphic population does not have a branching point), and contains a strategy with zero dispersal and a strategy with dispersal probability between one half and the ESS of the classic Hamilton-May model. The present model features surprisingly rich population dynamics with multiple equilibria and unprotected dimorphisms, but the evolutionarily stable dimorphism is always protected.}, } @article {pmid26729933, year = {2016}, author = {Gadagkar, R}, title = {Evolution of social behaviour in the primitively eusocial wasp Ropalidia marginata: do we need to look beyond kin selection?.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1687}, pages = {20150094}, pmid = {26729933}, issn = {1471-2970}, mesh = {Altruism ; Animals ; Behavior, Animal ; *Biological Evolution ; Ecosystem ; Female ; Genetic Fitness ; Models, Biological ; Nesting Behavior ; *Social Behavior ; Social Dominance ; Wasps/genetics/*physiology ; }, abstract = {Ropalidia marginata is a primitively eusocial wasp widely distributed in peninsular India. Although solitary females found a small proportion of nests, the vast majority of new nests are founded by small groups of females. In such multiple foundress nests, a single dominant female functions as the queen and lays eggs, while the rest function as sterile workers and care for the queen's brood. Previous attempts to understand the evolution of social behaviour and altruism in this species have employed inclusive fitness theory (kin selection) as a guiding framework. Although inclusive fitness theory is quite successful in explaining the high propensity of the wasps to found nests in groups, several features of their social organization suggest that forces other than kin selection may also have played a significant role in the evolution of this species. These features include lowering of genetic relatedness owing to polyandry and serial polygyny, nest foundation by unrelated individuals, acceptance of young non-nest-mates, a combination of well-developed nest-mate recognition and lack of intra-colony kin recognition, a combination of meek and docile queens and a decentralized self-organized work force, long reproductive queues with cryptic heir designates and conflict-free queen succession, all resulting in extreme intra-colony cooperation and inter-colony conflict.}, } @article {pmid26729929, year = {2016}, author = {Quiñones, AE and van Doorn, GS and Pen, I and Weissing, FJ and Taborsky, M}, title = {Negotiation and appeasement can be more effective drivers of sociality than kin selection.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1687}, pages = {20150089}, pmid = {26729929}, issn = {1471-2970}, mesh = {Aggression ; Animals ; Behavior, Animal ; *Biological Evolution ; Breeding ; Cichlids/genetics/physiology ; Computer Simulation ; *Cooperative Behavior ; Female ; Helping Behavior ; Male ; Models, Biological ; *Social Behavior ; Stochastic Processes ; }, abstract = {Two alternative frameworks explain the evolution of cooperation in the face of conflicting interests. Conflicts can be alleviated by kinship, the alignment of interests by virtue of shared genes, or by negotiation strategies, allowing mutually beneficial trading of services or commodities. Although negotiation often occurs in kin-structured populations, the interplay of kin- and negotiation-based mechanisms in the evolution of cooperation remains an unresolved issue. Inspired by the biology of a cooperatively breeding fish, we developed an individual-based simulation model to study the evolution of negotiation-based cooperation in relation to different levels of genetic relatedness. We show that the evolution of negotiation strategies leads to an equilibrium where subordinates appease dominants by conditional cooperation, resulting in high levels of help and low levels of aggression. This negotiation-based equilibrium can be reached both in the absence of relatedness and in a kin-structured population. However, when relatedness is high, evolution often ends up in an alternative equilibrium where subordinates help their kin unconditionally. The level of help at this kin-selected equilibrium is considerably lower than at the negotiation-based equilibrium, and it corresponds to a level reached when responsiveness is prevented from evolving in the simulations. A mathematical invasion analysis reveals that, quite generally, the alignment of payoffs due to the relatedness of interaction partners tends to impede selection for harsh but effective punishment of defectors. Hence kin structure will often hamper rather than facilitate the evolution of productive cooperation.}, } @article {pmid26729928, year = {2016}, author = {Rodrigues, AM and Kokko, H}, title = {Models of social evolution: can we do better to predict 'who helps whom to achieve what'?.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1687}, pages = {20150088}, pmid = {26729928}, issn = {1471-2970}, mesh = {Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Helping Behavior ; Humans ; Longevity ; *Models, Biological ; *Social Behavior ; }, abstract = {Models of social evolution and the evolution of helping have been classified in numerous ways. Two categorical differences have, however, escaped attention in the field. Models tend not to justify why they use a particular assumption structure about who helps whom: a large number of authors model peer-to-peer cooperation of essentially identical individuals, probably for reasons of mathematical convenience; others are inspired by particular cooperatively breeding species, and tend to assume unidirectional help where subordinates help a dominant breed more efficiently. Choices regarding what the help achieves (i.e. which life-history trait of the helped individual is improved) are similarly made without much comment: fecundity benefits are much more commonly modelled than survival enhancements, despite evidence that these may interact when the helped individual can perform life-history reallocations (load-lightening and related phenomena). We review our current theoretical understanding of effects revealed when explicitly asking 'who helps whom to achieve what', from models of mutual aid in partnerships to the very few models that explicitly contrast the strength of selection to help enhance another individual's fecundity or survival. As a result of idiosyncratic modelling choices in contemporary literature, including the varying degree to which demographic consequences are made explicit, there is surprisingly little agreement on what types of help are predicted to evolve most easily. We outline promising future directions to fill this gap.}, } @article {pmid26729926, year = {2016}, author = {Johnstone, RA and Rodrigues, AM}, title = {Cooperation and the common good.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1687}, pages = {20150086}, pmid = {26729926}, issn = {1471-2970}, mesh = {Animals ; Biological Evolution ; *Cooperative Behavior ; Game Theory ; Genetic Fitness ; Humans ; Models, Biological ; Selection, Genetic ; *Social Justice ; }, abstract = {In this paper, we draw the attention of biologists to a result from the economic literature, which suggests that when individuals are engaged in a communal activity of benefit to all, selection may favour cooperative sharing of resources even among non-relatives. Provided that group members all invest some resources in the public good, they should refrain from conflict over the division of these resources. The reason is that, given diminishing returns on investment in public and private goods, claiming (or ceding) a greater share of total resources only leads to the actor (or its competitors) investing more in the public good, such that the marginal costs and benefits of investment remain in balance. This cancels out any individual benefits of resource competition. We illustrate how this idea may be applied in the context of biparental care, using a sequential game in which parents first compete with one another over resources, and then choose how to allocate the resources they each obtain to care of their joint young (public good) versus their own survival and future reproductive success (private good). We show that when the two parents both invest in care to some extent, they should refrain from any conflict over the division of resources. The same effect can also support asymmetric outcomes in which one parent competes for resources and invests in care, whereas the other does not invest but refrains from competition. The fact that the caring parent gains higher fitness pay-offs at these equilibria suggests that abandoning a partner is not always to the latter's detriment, when the potential for resource competition is taken into account, but may instead be of benefit to the 'abandoned' mate.}, } @article {pmid26729925, year = {2016}, author = {Akçay, E and Van Cleve, J}, title = {There is no fitness but fitness, and the lineage is its bearer.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1687}, pages = {20150085}, pmid = {26729925}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; Cooperative Behavior ; Environment ; Female ; *Genetic Fitness ; Humans ; Male ; Models, Biological ; Models, Genetic ; Mutation ; Reproduction ; Selection, Genetic ; Social Behavior ; Turkeys ; }, abstract = {Inclusive fitness has been the cornerstone of social evolution theory for more than a half-century and has matured as a mathematical theory in the past 20 years. Yet surprisingly for a theory so central to an entire field, some of its connections to evolutionary theory more broadly remain contentious or underappreciated. In this paper, we aim to emphasize the connection between inclusive fitness and modern evolutionary theory through the following fact: inclusive fitness is simply classical Darwinian fitness, averaged over social, environmental and demographic states that members of a gene lineage experience. Therefore, inclusive fitness is neither a generalization of classical fitness, nor does it belong exclusively to the individual. Rather, the lineage perspective emphasizes that evolutionary success is determined by the effect of selection on all biological and environmental contexts that a lineage may experience. We argue that this understanding of inclusive fitness based on gene lineages provides the most illuminating and accurate picture and avoids pitfalls in interpretation and empirical applications of inclusive fitness theory.}, } @article {pmid26729924, year = {2016}, author = {Taborsky, M and Frommen, JG and Riehl, C}, title = {Correlated pay-offs are key to cooperation.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1687}, pages = {20150084}, pmid = {26729924}, issn = {1471-2970}, mesh = {Altruism ; Animals ; Behavior, Animal ; *Biological Evolution ; Cognition ; *Cooperative Behavior ; Humans ; Social Behavior ; }, abstract = {The general belief that cooperation and altruism in social groups result primarily from kin selection has recently been challenged, not least because results from cooperatively breeding insects and vertebrates have shown that groups may be composed mainly of non-relatives. This allows testing predictions of reciprocity theory without the confounding effect of relatedness. Here, we review complementary and alternative evolutionary mechanisms to kin selection theory and provide empirical examples of cooperative behaviour among unrelated individuals in a wide range of taxa. In particular, we focus on the different forms of reciprocity and on their underlying decision rules, asking about evolutionary stability, the conditions selecting for reciprocity and the factors constraining reciprocal cooperation. We find that neither the cognitive requirements of reciprocal cooperation nor the often sequential nature of interactions are insuperable stumbling blocks for the evolution of reciprocity. We argue that simple decision rules such as 'help anyone if helped by someone' should get more attention in future research, because empirical studies show that animals apply such rules, and theoretical models find that they can create stable levels of cooperation under a wide range of conditions. Owing to its simplicity, behaviour based on such a heuristic may in fact be ubiquitous. Finally, we argue that the evolution of exchange and trading of service and commodities among social partners needs greater scientific focus.}, } @article {pmid26726282, year = {2015}, author = {Leighton, GM and Echeverri, S and Heinrich, D and Kolberg, H}, title = {Relatedness predicts multiple measures of investment in cooperative nest construction in sociable weavers.}, journal = {Behavioral ecology and sociobiology}, volume = {69}, number = {11}, pages = {1835-1843}, pmid = {26726282}, issn = {0340-5443}, support = {K12 GM000708/GM/NIGMS NIH HHS/United States ; }, abstract = {Although communal goods are often critical to society, they are simultaneously susceptible to exploitation and are evolutionarily stable only if mechanisms exist to curtail exploitation. Mechanisms such as punishment and kin selection have been offered as general explanations for how communal resources can be maintained. Evidence for these mechanisms comes largely from humans and social insects, leaving their generality in question. To assess how communal resources are maintained, we observed cooperative nest construction in sociable weavers (Philetairus socius). The communal nest of sociable weavers provides thermal benefits for all individuals but requires continual maintenance. We observed cooperative nest construction and also recorded basic morphological characteristics. We also collected blood samples, performed next-generation sequencing, and isolated 2358 variable single nucleotide polymorphisms (SNPs) to estimate relatedness. We find that relatedness predicts investment in cooperative nest construction, while no other morphological characters significantly explain cooperative output. We argue that indirect benefits are a critical fitness component for maintaining the cooperative behavior that maintains the communal good.}, } @article {pmid26685796, year = {2016}, author = {Marsh, AA}, title = {Neural, cognitive, and evolutionary foundations of human altruism.}, journal = {Wiley interdisciplinary reviews. Cognitive science}, volume = {7}, number = {1}, pages = {59-71}, doi = {10.1002/wcs.1377}, pmid = {26685796}, issn = {1939-5086}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Brain/*physiology ; Cognition/*physiology ; Empathy ; Humans ; Social Behavior ; }, abstract = {This article considers three forms of altruism from both a psychological and a neural perspective, with an emphasis on homologies that can be observed across species and potentially illuminate altruism's evolutionary origins. Kin-based altruism benefits biological relatives and, according to the theory of inclusive fitness, is ultimately beneficial to the altruist from a genetic standpoint. Kin selection adequately explains some altruistic behavior, but it is not applicable to much human altruism. Little is known about the neural processes that support it, but they may include cortical regions involved in processing autobiographical memory and the identities of familiar others. Reciprocity-based altruism is performed in expectation of future rewards and is supported by dopaminergic cortico-striatal networks that guide behavior according to anticipated rewards. Care-based altruism is aimed at improving the well-being of distressed and vulnerable individuals and is closely linked to empathic concern. This form of altruism is thought to rely on the subcortical neural systems that support parental care, particularly structures densely populated with receptors for the hormones oxytocin and vasopressin, including the amygdala, stria terminalis, and striatum. The amygdala may be a particularly important convergence point for care-based altruism because of its dual role in responding both to cues that signal infantile vulnerability and those that signal distress. Research on altruism continues to converge across disciplines, but more research linking molecular-level neural processes to altruistic behavior in humans and other species is needed, as is research on how various forms of altruism intersect. For further resources related to this article, please visit the WIREs website.}, } @article {pmid26679493, year = {2016}, author = {Okasha, S and Martens, J}, title = {Hamilton's rule, inclusive fitness maximization, and the goal of individual behaviour in symmetric two-player games.}, journal = {Journal of evolutionary biology}, volume = {29}, number = {3}, pages = {473-482}, doi = {10.1111/jeb.12808}, pmid = {26679493}, issn = {1420-9101}, mesh = {Alleles ; Animals ; Behavior, Animal ; *Biological Evolution ; *Genetic Fitness ; *Models, Biological ; Models, Genetic ; }, abstract = {Hamilton's original work on inclusive fitness theory assumed additivity of costs and benefits. Recently, it has been argued that an exact version of Hamilton's rule for the spread of a pro-social allele (rb > c) holds under nonadditive pay-offs, so long as the cost and benefit terms are defined as partial regression coefficients rather than pay-off parameters. This article examines whether one of the key components of Hamilton's original theory can be preserved when the rule is generalized to the nonadditive case in this way, namely that evolved organisms will behave as if trying to maximize their inclusive fitness in social encounters.}, } @article {pmid26674954, year = {2015}, author = {Martin, ES and Long, TA}, title = {Are flies kind to kin? The role of intra- and inter-sexual relatedness in mediating reproductive conflict.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1821}, pages = {20151991}, pmid = {26674954}, issn = {1471-2954}, mesh = {Animals ; Conflict, Psychological ; Courtship ; Drosophila melanogaster/genetics/*physiology ; Female ; Longevity ; Male ; Reproduction ; Sexual Behavior, Animal ; Social Behavior ; }, abstract = {As individual success often comes at the expense of others, interactions between the members of a species are frequently antagonistic, especially in the context of reproduction. In theory, this conflict may be reduced in magnitude when kin interact, as cooperative behaviour between relatives can result in increased inclusive fitness. Recent tests of the potential role of cooperative behaviour between brothers in Drosophila melanogaster have proved to be both exciting and controversial. We set out to replicate these experiments, which have profound implications for the study of kin selection and sexual conflict, and to expand upon them by also examining the potential role of kinship between males and females in reproductive interactions. While we did observe reduced fighting and courtship effort between competing brothers, contrary to previous studies we did not detect any fitness benefit to females as a result of the modification of male antagonistic behaviours. Furthermore, we did not observe any differential treatment of females by their brothers, as would be expected if the intensity of sexual conflict was mediated by kin selection. In the light of these results, we propose an alternative explanation for observed differences in male-male conflict and provide preliminary empirical support for this hypothesis.}, } @article {pmid26674073, year = {2015}, author = {Sutton, GJ and Hoskins, AJ and Arnould, JP}, title = {Benefits of Group Foraging Depend on Prey Type in a Small Marine Predator, the Little Penguin.}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0144297}, pmid = {26674073}, issn = {1932-6203}, mesh = {Animals ; Models, Theoretical ; *Predatory Behavior ; *Spheniscidae ; }, abstract = {Group foraging provides predators with advantages in over-powering prey larger than themselves or in aggregating small prey for efficient exploitation. For group-living predatory species, cooperative hunting strategies provide inclusive fitness benefits. However, for colonial-breeding predators, the benefit pay-offs of group foraging are less clear due to the potential for intra-specific competition. We used animal-borne cameras to determine the prey types, hunting strategies, and success of little penguins (Eudyptula minor), a small, colonial breeding air-breathing marine predator that has recently been shown to display extensive at-sea foraging associations with conspecifics. Regardless of prey type, little penguins had a higher probability of associating with conspecifics when hunting prey that were aggregated than when prey were solitary. In addition, success was greater when individuals hunted schooling rather than solitary prey. Surprisingly, however, success on schooling prey was similar or greater when individuals hunted on their own than when with conspecifics. These findings suggest individuals may be trading-off the energetic gains of solitary hunting for an increased probability of detecting prey within a spatially and temporally variable prey field by associating with conspecifics.}, } @article {pmid26667274, year = {2016}, author = {Korb, J and Heinze, J}, title = {Major Hurdles for the Evolution of Sociality.}, journal = {Annual review of entomology}, volume = {61}, number = {}, pages = {297-316}, doi = {10.1146/annurev-ento-010715-023711}, pmid = {26667274}, issn = {1545-4487}, mesh = {Animals ; *Biological Evolution ; Insecta/*physiology ; Social Behavior ; Vertebrates/physiology ; }, abstract = {Why do most animals live solitarily, while complex social life is restricted to a few cooperatively breeding vertebrates and social insects? Here, we synthesize concepts and theories in social evolution and discuss its underlying ecological causes. Social evolution can be partitioned into (a) formation of stable social groups, (b) evolution of helping, and (c) transition to a new evolutionary level. Stable social groups rarely evolve due to competition over food and/or reproduction. Food competition is overcome in social insects with central-place foraging or bonanza-type food resources, whereas competition over reproduction commonly occurs because staying individuals are rarely sterile. Hence, the evolution of helping is shaped by direct and indirect fitness options and helping is only altruism if it reduces the helper's direct fitness. The helper's capability to gain direct fitness also creates within-colony conflict. This prevents transition to a new evolutionary level.}, } @article {pmid26655360, year = {2015}, author = {Farrell, EJ and Úbeda, F and Gardner, A}, title = {Intragenomic Conflict over Dispersal.}, journal = {The American naturalist}, volume = {186}, number = {3}, pages = {E61-71}, doi = {10.1086/682275}, pmid = {26655360}, issn = {1537-5323}, mesh = {*Animal Distribution ; Animals ; *Biological Evolution ; Female ; Genomic Imprinting ; Male ; Models, Genetic ; Reproduction/genetics ; Sexual Behavior, Animal ; }, abstract = {Intragenomic conflict may arise when social partners are more related through one parent than the other-for example, owing to individuals or gametes of one sex dispersing further prior to fertilization. In particular, genes originating from the former parent are favored to promote selflessness, and those originating from the latter parent are favored to promote selfishness. While the impact of patterns of dispersal on the evolution of intragenomic conflict has received recent attention, the consequences of intragenomic conflict for the evolution of dispersal remain to be explored. We suggest that if the evolution of dispersal is driven at least in part by kin selection, differential relatedness of social partners via their mothers versus their fathers may lead to an intragenomic conflict, with maternal-origin genes and paternal-origin genes favoring different rates of dispersal. As an illustration, we extend a classic model of the evolution of dispersal to explore how intragenomic conflict may arise between an individual's maternal-origin and paternal-origin genes over whether that individual should disperse in order to ease kin competition. Our analysis reveals extensive potential for intragenomic conflict over dispersal and predicts that genes underpinning dispersal phenotypes may exhibit parent-of-origin-specific expression, which may facilitate their discovery.}, } @article {pmid26629334, year = {2015}, author = {Kell, D and Potgieter, M and Pretorius, E}, title = {Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology.}, journal = {F1000Research}, volume = {4}, number = {}, pages = {179}, pmid = {26629334}, issn = {2046-1402}, support = {BB/M017702/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.}, } @article {pmid26621708, year = {2016}, author = {Schwarz, F and Springer, SA and Altheide, TK and Varki, NM and Gagneux, P and Varki, A}, title = {Human-specific derived alleles of CD33 and other genes protect against postreproductive cognitive decline.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {113}, number = {1}, pages = {74-79}, pmid = {26621708}, issn = {1091-6490}, support = {P01 HL107150/HL/NHLBI NIH HHS/United States ; R01 GM095882/GM/NIGMS NIH HHS/United States ; P01HL107150/HL/NHLBI NIH HHS/United States ; R01GM095882/GM/NIGMS NIH HHS/United States ; }, mesh = {Alleles ; Alternative Splicing ; Alzheimer Disease/*genetics ; Animals ; Apolipoproteins E/genetics ; Biological Evolution ; Brain/*physiopathology ; Cerebrovascular Disorders/genetics ; Cognition Disorders/*genetics ; Fertility/genetics ; *Genetic Fitness ; Genetic Loci ; Humans ; Pan troglodytes ; Selection, Genetic ; Sialic Acid Binding Ig-like Lectin 3/genetics/*physiology ; }, abstract = {The individuals of most vertebrate species die when they can no longer reproduce. Humans are a rare exception, having evolved a prolonged postreproductive lifespan. Elders contribute to cooperative offspring care, assist in foraging, and communicate important ecological and cultural knowledge, increasing the survival of younger individuals. Age-related deterioration of cognitive capacity in humans compromises these benefits and also burdens the group with socially costly members. We investigated the contribution of the immunoregulatory receptor CD33 to a uniquely human postreproductive disease, Alzheimer's dementia. Surprisingly, even though selection at advanced age is expected to be weak, a CD33 allele protective against Alzheimer's disease is derived and unique to humans and favors a functional molecular state of CD33 resembling that of the chimpanzee. Thus, derived alleles may be compensatory and restore interactions altered as a consequence of human-specific brain evolution. We found several other examples of derived alleles at other human loci that protect against age-related cognitive deterioration arising from neurodegenerative disease or cerebrovascular insufficiency. Selection by inclusive fitness may be strong enough to favor alleles protecting specifically against cognitive decline in postreproductive humans. Such selection would operate by maximizing the contributions of postreproductive individuals to the fitness of younger kin.}, } @article {pmid26597647, year = {2016}, author = {VanderLaan, DP and Petterson, LJ and Vasey, PL}, title = {Femininity and Kin-Directed Altruism in Androphilic Men: A Test of an Evolutionary Developmental Model.}, journal = {Archives of sexual behavior}, volume = {45}, number = {3}, pages = {619-633}, doi = {10.1007/s10508-015-0632-z}, pmid = {26597647}, issn = {1573-2800}, support = {//Canadian Institutes of Health Research/Canada ; }, mesh = {Adolescent ; Adult ; *Altruism ; *Arousal ; Biological Evolution ; Canada ; *Family Relations ; Female ; *Femininity ; *Homosexuality, Male ; Humans ; Male ; Middle Aged ; Models, Theoretical ; Sexual Behavior ; Surveys and Questionnaires ; Young Adult ; }, abstract = {Androphilia refers to sexual attraction and arousal toward males whereas gynephilia refers to sexual attraction and arousal toward females. This study tested the adaptive feminine phenotype model of the evolution of male androphilia via kin selection, which posits that the development of an evolved disposition toward elevated kin-directed altruism among androphilic males is contingent on the behavioral expression of femininity. Gynephilic men, androphilic women, and androphilic men (N = 387) completed measures of childhood and adulthood gender expression and concern for kin's well-being. Adulthood femininity correlated positively with uncle/aunt-like tendencies among androphilic men and women. Although androphilic women reported greater willingness to invest in nieces and nephews than gynephilic and androphilic men, mediation analyses indicated that adult femininity completely mediated these group differences. In addition, changes in the expression of femininity between childhood and adulthood were associated with parallel changes in concern for the well-being of kin among androphilic men. Thus, these findings suggest that femininity is key to the expression of kin-directed altruism among androphilic males and may have been important in the evolution of male androphilia.}, } @article {pmid26583897, year = {2015}, author = {Bourke, AF}, title = {Social Evolution: Uneasy Lies the Head.}, journal = {Current biology : CB}, volume = {25}, number = {22}, pages = {R1077-9}, doi = {10.1016/j.cub.2015.09.071}, pmid = {26583897}, issn = {1879-0445}, mesh = {Animals ; Reproduction ; *Social Behavior ; *Wasps ; }, abstract = {Inclusive fitness theory explains why workers in insect societies sometimes kill their queen. As the theory predicts, workers in a wasp species are more likely to act matricidally when more highly related to potential worker offspring.}, } @article {pmid26582031, year = {2015}, author = {Carter, GG and Wilkinson, GS}, title = {Social benefits of non-kin food sharing by female vampire bats.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1819}, pages = {}, pmid = {26582031}, issn = {1471-2954}, mesh = {Animals ; Chiroptera/genetics/*physiology ; *Cooperative Behavior ; Feeding Behavior/*physiology ; Female ; Food ; }, abstract = {Regurgitations of blood among vampire bats appear to benefit both direct and indirect fitness. To maximize inclusive fitness, reciprocal food sharing should occur among close kin. Why then do females with kin roost-mates help non-kin? We tested the hypothesis that helping non-kin increases a bat's success at obtaining future donations by expanding its network of potential donors. On six occasions, we individually fasted 14 adult females and measured donations from 28 possible donors. Each female was fasted before, during and after a treatment period, when we prevented donations from past donors (including 10 close relatives) by simultaneously fasting or removing them. This experiment was designed to detect partner switching and yielded three main results. First, females received less food when we prevented donations from a past donor versus a control bat. Donors within a group are therefore not interchangeable. Second, the treatment increased the variance in donors' contributions to food received by subjects, suggesting the possibility of alternative responses to a partner's inability to reciprocate. Finally, bats that fed more non-kin in previous years had more donors and received more food during the treatment. These results indicate that a bat can expand its network of possible donors by helping non-kin.}, } @article {pmid26582022, year = {2015}, author = {Jungwirth, A and Taborsky, M}, title = {First- and second-order sociality determine survival and reproduction in cooperative cichlids.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1819}, pages = {}, pmid = {26582022}, issn = {1471-2954}, mesh = {Animals ; Biological Evolution ; Cichlids/*physiology ; Female ; *Longevity ; Male ; Population Density ; *Reproduction ; Seasons ; *Social Behavior ; Zambia ; }, abstract = {Cooperative breeders serve as a model to study the evolution of cooperation, where costs and benefits of helping are typically scrutinized at the level of group membership. However, cooperation is often observed in multi-level social organizations involving interactions among individuals at various levels. Here, we argue that a full understanding of the adaptive value of cooperation and the evolution of complex social organization requires identifying the effect of different levels of social organization on direct and indirect fitness components. Our long-term field data show that in the cooperatively breeding, colonial cichlid fish Neolamprologus pulcher, both large group size and high colony density significantly raised group persistence. Neither group size nor density affected survival at the individual level, but they had interactive effects on reproductive output; large group size raised productivity when local population density was low, whereas in contrast, small groups were more productive at high densities. Fitness estimates of individually marked fish revealed indirect fitness benefits associated with staying in large groups. Inclusive fitness, however, was not significantly affected by group size, because the direct fitness component was not increased in larger groups. Together, our findings highlight that the reproductive output of groups may be affected in opposite directions by different levels of sociality, and that complex forms of sociality and costly cooperation may evolve in the absence of large indirect fitness benefits and the influence of kin selection.}, } @article {pmid26578231, year = {2016}, author = {Garg, R and Vogelgesang, J and Kelly, K}, title = {Impact of Genetic Counseling and Testing on Altruistic Motivations to Test for BRCA1/2: a Longitudinal Study.}, journal = {Journal of genetic counseling}, volume = {25}, number = {3}, pages = {572-582}, pmid = {26578231}, issn = {1573-3599}, support = {R03 CA128459/CA/NCI NIH HHS/United States ; }, mesh = {Adult ; Aged ; Aged, 80 and over ; Female ; Genes, BRCA1 ; Genes, BRCA2 ; Genetic Counseling/*psychology ; *Genetic Predisposition to Disease ; *Genetic Testing ; Humans ; Longitudinal Studies ; Medical History Taking ; Middle Aged ; *Motivation ; Mutation ; Neoplasms/*genetics ; Young Adult ; }, abstract = {Despite the importance of altruism in an individual's participation in genetic counseling and testing, little research has explored the change in altruistic motivations to test over time. This study analyzed altruistic motivations to test and change in altruistic motivations after genetic counseling and testing among individuals (N = 120) at elevated risk for BRCA1/2 mutations. The perceived benefits of genetic testing were assessed and utilized in a mixed-methods, repeated measures design at three time points: pre-counseling, counseling and post-genetic testing, along with transcripts of genetic counseling sessions. Qualitative analysis using an immersion/crystallization method resulted in six common perceived benefits of testing: cancer prevention, awareness, family's survival, relief from anxiety, for science, and future planning. Perceived benefits were then coded into three categories according to Hamilton's kin selection theory: altruistic motivation, personal motivation, and motivation for mutual benefit. At pre-counseling, those with a personal cancer history (p = 0.003) and those with one or more children (p = 0.013), were significantly more likely to cite altruistic motivations to test. Altruistic motivations significantly increased post-counseling (p = 0.01) but declined post-testing (p < 0.001). Labov's narrative analysis further elucidated the context of altruistic and personal motivations. The possibility of a positive test result might have led those with personal history of cancer to have altruistic motivations for testing. Genetic counseling may have increased altruistic motivations to help family and may be a prime opportunity to discuss other forms of altruism.}, } @article {pmid26577076, year = {2015}, author = {Riehl, C and Stern, CA}, title = {How cooperatively breeding birds identify relatives and avoid incest: New insights into dispersal and kin recognition.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {37}, number = {12}, pages = {1303-1308}, doi = {10.1002/bies.201500120}, pmid = {26577076}, issn = {1521-1878}, mesh = {Animals ; Birds/*physiology ; Breeding/methods ; Cooperative Behavior ; Humans ; Sexual Behavior, Animal/*physiology ; }, abstract = {Cooperative breeding in birds typically occurs when offspring - usually males - delay dispersal from their natal group, remaining with the family to help rear younger kin. Sex-biased dispersal is thought to have evolved in order to reduce the risk of inbreeding, resulting in low relatedness between mates and the loss of indirect fitness benefits for the dispersing sex. In this review, we discuss several recent studies showing that dispersal patterns are more variable than previously thought, often leading to complex genetic structure within cooperative avian societies. These empirical findings accord with recent theoretical models suggesting that sex- biased dispersal is neither necessary, nor always sufficient, to prevent inbreeding. The ability to recognize relatives, primarily by learning individual or group-specific vocalizations, may play a more important role in incest avoidance than currently appreciated.}, } @article {pmid26555844, year = {2016}, author = {Lion, S}, title = {Moment equations in spatial evolutionary ecology.}, journal = {Journal of theoretical biology}, volume = {405}, number = {}, pages = {46-57}, doi = {10.1016/j.jtbi.2015.10.014}, pmid = {26555844}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Ecology ; Introduced Species ; *Models, Theoretical ; Population Dynamics ; }, abstract = {How should we model evolution in spatially structured populations? Here, I review an evolutionary ecology approach based on the technique of spatial moment equations. I first provide a mathematical underpinning to the derivation of equations for the densities of various spatial configurations in network-based models. I then show how this spatial ecological framework can be coupled with an adaptive dynamics approach to compute the invasion fitness of a rare mutant in a resident population at equilibrium. Under the additional assumption that mutations have small phenotypic effects, I show that the selection gradient can be expressed as a function of neutral measures of genetic and demographic structure. I discuss the connections between this approach and inclusive fitness theory, as well as the applicability and limits of this technique. My main message is that spatial moment equations can be used as a means to obtain compact qualitative arguments about the evolution of life-history traits for a variety of life cycles.}, } @article {pmid26548351, year = {2016}, author = {Kapranas, A and Maher, AM and Griffin, CT}, title = {Higher relatedness mitigates mortality in a nematode with lethal male fighting.}, journal = {Journal of evolutionary biology}, volume = {29}, number = {2}, pages = {344-351}, doi = {10.1111/jeb.12786}, pmid = {26548351}, issn = {1420-9101}, mesh = {*Aggression ; Animals ; Biological Evolution ; Cooperative Behavior ; Female ; Insecta/parasitology ; Male ; Nematoda/*physiology ; }, abstract = {According to kin selection theory, individuals show less aggression towards their relatives. Limited dispersal promotes interactions among relatives but also increases competition among them. The evolution of cooperation in viscous populations has been subject of mainly theoretical exploration. We investigated the influence of relatedness on aggression in males of entomopathogenic nematode Steinernema longicaudum that engage in lethal fighting. In a series of in vitro experiments, we found that both competitor male group size and relatedness influence male mortality rates. Higher relatedness led to progressively lower rates of male mortality. In experimentally infected insects, wherein large numbers of males and females interact, the proportion of dead and paralysed (= terminally injured) males was higher when infection was established by infective juveniles originating from a mixture of three lines than in those infected by a single line. The results collectively show that Steinernema longicaudum males recognize their kin and consequently male mortality rates are lower in groups consisting of more related males. Furthermore, this monotonic negative relationship between aggression and relatedness suggests that kin selection benefits are still substantial even under extreme competition. Our experiments also suggest that kin recognition in entomopathogenic nematodes has a genetic basis rather than being strictly based on environmental cues. We discuss our findings within the theoretical context of the evolution of altruistic/cooperative behaviour in structured populations.}, } @article {pmid26543568, year = {2015}, author = {Grønstøl, G and Blomqvist, D and Pauliny, A and Wagner, RH}, title = {Kin selection and polygyny: can relatedness lower the polygyny threshold?.}, journal = {Royal Society open science}, volume = {2}, number = {6}, pages = {140409}, pmid = {26543568}, issn = {2054-5703}, abstract = {Resource polygyny incurs costs of having to share breeding resources for female breeders. When breeding with a relative, however, such costs may be lessened by indirect fitness benefits through kin selection, while benefits from mutualistic behaviour, such as communal defence, may increase. If so, females should be less resistant to sharing a territory with a related female than with a non-related one. We investigated whether kin selection may lower the threshold of breeding polygynously, predicting a closer relatedness between polygynous females breeding on the same territory than between females breeding on different territories. Northern lapwings, Vanellus vanellus, are suitable for testing this hypothesis as they are commonly polygynous, both sexes take part in nest defence, and the efficiency of nest defence increases with the number of defenders. Using an index of relatedness derived from DNA fingerprinting, we found that female lapwings that shared polygynous dyads were on average twice as closely related as were random females. Furthermore, relatedness did not correlate with distance between breeders, indicating that our findings cannot be explained by natal philopatry alone. Our results suggest that the polygyny threshold in lapwings may be lowered by inclusive fitness advantages of kin selection.}, } @article {pmid26530161, year = {2015}, author = {Swenson, SA}, title = {'Morals can not be drawn from facts but guidance may be': the early life of W.D. Hamilton's theory of inclusive fitness.}, journal = {British journal for the history of science}, volume = {48}, number = {4}, pages = {543-563}, doi = {10.1017/S0007087415000643}, pmid = {26530161}, issn = {1474-001X}, mesh = {*Altruism ; *Biological Evolution ; *Genetic Fitness ; History, 20th Century ; Humans ; *Morals ; Sociobiology/*history ; }, abstract = {W.D. Hamilton's theory of inclusive fitness saw the evolution of altruism from the point of view of the gene. It was at heart a theory of limits, redefining altruistic behaviours as ultimately selfish. This theory inspired two controversial texts published almost in tandem, E.O. Wilson's Sociobiology: The New Synthesis (1975) and Richard Dawkins's The Selfish Gene (1976). When Wilson and Dawkins were attacked for their evolutionary interpretations of human societies, they claimed a distinction between reporting what is and declaring what ought to be. Can the history of sociobiological theories be so easily separated from its sociopolitical context? This paper draws upon unpublished materials from the 1960s and early 1970s and documents some of the ways in which Hamilton saw his research as contributing to contemporary concerns. It pays special attention to the 1969 Man and Beast Smithsonian Institution symposium in order to explore the extent to which Hamilton intended his theory to be merely descriptive versus prescriptive. From this, we may see that Hamilton was deeply concerned about the political chaos he perceived in the world around him, and hoped to arrive at a level of self-understanding through science that could inform a new social order.}, } @article {pmid26492510, year = {2016}, author = {Kuijper, B and Johnstone, RA}, title = {Parental effects and the evolution of phenotypic memory.}, journal = {Journal of evolutionary biology}, volume = {29}, number = {2}, pages = {265-276}, doi = {10.1111/jeb.12778}, pmid = {26492510}, issn = {1420-9101}, mesh = {Adaptation, Physiological ; Animal Distribution ; Animals ; *Biological Evolution ; Environment ; Genetic Fitness ; *Models, Biological ; *Phenotype ; Selection, Genetic ; }, abstract = {Despite growing evidence for nongenetic inheritance, the ecological conditions that favour the evolution of heritable parental or grandparental effects remain poorly understood. Here, we systematically explore the evolution of parental effects in a patch-structured population with locally changing environments. When selection favours the production of a mix of offspring types, this mix differs according to the parental phenotype, implying that parental effects are favoured over selection for bet-hedging in which the mixture of offspring phenotypes produced does not depend on the parental phenotype. Positive parental effects (generating a positive correlation between parental and offspring phenotype) are favoured in relatively stable habitats and when different types of local environment are roughly equally abundant, and can give rise to long-term parental inheritance of phenotypes. By contrast, unstable habitats can favour negative parental effects (generating a negative correlation between parental and offspring phenotype), and under these circumstances, even slight asymmetries in the abundance of local environmental states select for marked asymmetries in transmission fidelity.}, } @article {pmid26474156, year = {2015}, author = {Shakhar, K and Shakhar, G}, title = {Why Do We Feel Sick When Infected--Can Altruism Play a Role?.}, journal = {PLoS biology}, volume = {13}, number = {10}, pages = {e1002276}, pmid = {26474156}, issn = {1545-7885}, mesh = {*Altruism ; Animals ; Attitude to Health ; *Biological Evolution ; Cost of Illness ; Humans ; Illness Behavior ; *Infection Control ; Infections/immunology/*physiopathology/transmission ; *Models, Biological ; Sick Role ; }, abstract = {When we contract an infection, we typically feel sick and behave accordingly. Symptoms of sickness behavior (SB) include anorexia, hypersomnia, depression, and reduced social interactions. SB affects species spanning from arthropods to vertebrates, is triggered nonspecifically by viruses, bacteria, and parasites, and is orchestrated by a complex network of cytokines and neuroendocrine pathways; clearly, it has been naturally selected. Nonetheless, SB seems evolutionarily costly: it promotes starvation and predation and reduces reproductive opportunities. How could SB persist? Former explanations focused on individual fitness, invoking improved resistance to pathogens. Could prevention of disease transmission, propagating in populations through kin selection, also contribute to SB?}, } @article {pmid26471069, year = {2016}, author = {Lee, W and van Baalen, M and Jansen, VA}, title = {Siderophore production and the evolution of investment in a public good: An adaptive dynamics approach to kin selection.}, journal = {Journal of theoretical biology}, volume = {388}, number = {}, pages = {61-71}, doi = {10.1016/j.jtbi.2015.09.038}, pmid = {26471069}, issn = {1095-8541}, support = {BB/G00787X/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/I024585/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/I024682/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adaptation, Physiological/genetics ; *Algorithms ; Bacteria/*genetics/*metabolism ; *Directed Molecular Evolution ; Iron/metabolism ; *Models, Genetic ; Pseudomonas aeruginosa/genetics/metabolism ; Selection, Genetic ; Siderophores/*biosynthesis ; }, abstract = {Like many other bacteria, Pseudomonas aeruginosa sequesters iron from the environment through the secretion, and subsequent uptake, of iron-binding molecules. As these molecules can be taken up by other bacteria in the population than those who secreted them, this is a form of cooperation through a public good. Traditionally, this problem has been studied by comparing the relative fitnesses of siderophore-producing and non-producing strains, but this gives no information about the fate of strains that do produce intermediate amounts of siderophores. Here, we investigate theoretically how the amount invested in this form of cooperation evolves. We use a mechanistic description of the laboratory protocols used in experimental evolution studies to describe the competition and cooperation of the bacteria. From this dynamical model we derive the fitness following the adaptive dynamics method. The results show how selection is driven by local siderophore production and local competition. Because siderophore production reduces the growth rate, local competition decreases with the degree of relatedness (which is a dynamical variable in our model). Our model is not restricted to the analysis of small phenotypic differences and allows for theoretical exploration of the effects of large phenotypic differences between cooperators and cheats. We predict that an intermediate ESS level of cooperation (molecule production) should exist. The adaptive dynamics approach allows us to assess evolutionary stability, which is often not possible in other kin-selection models. We found that selection can lead to an intermediate strategy which in our model is always evolutionarily stable, yet can allow invasion of strategies that are much more cooperative. Our model describes the evolution of a public good in the context of the ecology of the microorganism, which allows us to relate the extent of production of the public good to the details of the interactions.}, } @article {pmid26460512, year = {2015}, author = {Griesser, M and Halvarsson, P and Drobniak, SM and Vilà, C}, title = {Fine-scale kin recognition in the absence of social familiarity in the Siberian jay, a monogamous bird species.}, journal = {Molecular ecology}, volume = {24}, number = {22}, pages = {5726-5738}, doi = {10.1111/mec.13420}, pmid = {26460512}, issn = {1365-294X}, mesh = {*Aggression ; Animals ; Biological Evolution ; Female ; Male ; Microsatellite Repeats ; Models, Biological ; Passeriformes/*genetics ; Sequence Analysis, DNA ; *Social Behavior ; }, abstract = {Kin recognition is a critical element to kin cooperation, and in vertebrates, it is primarily based on associative learning. Recognition of socially unfamiliar kin occurs rarely, and it is reported only in vertebrate species where promiscuity prevents recognition of first-order relatives. However, it is unknown whether the recognition of socially unfamiliar kin can evolve in monogamous species. Here, we investigate whether genetic relatedness modulates aggression among group members in Siberian jays (Perisoreus infaustus). This bird species is genetically and socially monogamous and lives in groups that are formed through the retention of offspring beyond independence, and the immigration of socially unfamiliar nonbreeders. Observations on feeders showed that genetic relatedness modulated aggression of breeders towards immigrants in a graded manner, in that they chased most intensely the immigrant group members that were genetically the least related. However, cross-fostering experiments showed that breeders were equally tolerant towards their own and cross-fostered young swapped as nestlings. Thus, breeders seem to use different mechanisms to recognize socially unfamiliar individuals and own offspring. As Siberian jays show a high degree of nepotism during foraging and predator encounters, inclusive fitness benefits may play a role for the evolution of fine-scale kin recognition. More generally, our results suggest that fine-graded kin recognition can evolve independently of social familiarity, highlighting the evolutionary importance of kin recognition for social species.}, } @article {pmid26454155, year = {2015}, author = {Rousset, F}, title = {Regression, least squares, and the general version of inclusive fitness.}, journal = {Evolution; international journal of organic evolution}, volume = {69}, number = {11}, pages = {2963-2970}, doi = {10.1111/evo.12791}, pmid = {26454155}, issn = {1558-5646}, mesh = {Alleles ; *Genetic Fitness ; Least-Squares Analysis ; *Models, Genetic ; }, abstract = {A general version of inclusive fitness based on regression is rederived with minimal mathematics and directly from the verbal interpretation of its terms that motivated the original formulation of the inclusive fitness concept. This verbal interpretation is here extended to provide the two relationships required to determine the two coefficients -c and b. These coefficients retain their definition as expected effects on the fitness of an individual, respectively of a change in allelic state of this individual, and of correlated change in allelic state of social partners. The known least-squares formulation of the relationships determining b and c can be immediately deduced and shown to be equivalent to this new formulation. These results make clear that criticisms of the mathematical tools (in particular least-squares regression) previously used to derive this version of inclusive fitness are misdirected.}, } @article {pmid26445661, year = {2015}, author = {Inoue, MN and Ito, F and Goka, K}, title = {Queen execution increases relatedness among workers of the invasive Argentine ant, Linepithema humile.}, journal = {Ecology and evolution}, volume = {5}, number = {18}, pages = {4098-4107}, pmid = {26445661}, issn = {2045-7758}, abstract = {Polygyny in social insects can greatly reduce within-nest genetic relatedness. In polygynous ant species, potential rival queens in colonies with multiple queens are often executed by other queens, workers, or both. The Argentine ant, Linepithema humile, native to South America, forms a "supercolony" that is composed of a large number of nests and is considered to contribute to the ant's invasion success. Currently, four mutually antagonistic supercolonies are contiguously distributed within a small area of Japan. Here, we analyzed the genetic structure and relatedness within and among the four supercolonies using microsatellite markers to clarify how L. humile maintains its supercoloniality. The results of AMOVA and BASP, the F ST values, and the existence of several private alleles indicated that the L. humile population in the Kobe area had a characteristic genetic structure. Within a given supercolony, there was significant genetic differentiation (F ST) among workers collected in May and those collected in September. The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies. This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution. From the perspective of kin selection, workers collectively eliminate queens, thereby increasing their own inclusive fitness. Restricted gene flow among supercolonies, together with mating with sib and queen execution, could help to maintain the unique social structure of L. humile, the distribution of which is expanding worldwide.}, } @article {pmid26416979, year = {2016}, author = {Ronai, I and Oldroyd, BP and Barton, DA and Cabanes, G and Lim, J and Vergoz, V}, title = {Anarchy Is a Molecular Signature of Worker Sterility in the Honey Bee.}, journal = {Molecular biology and evolution}, volume = {33}, number = {1}, pages = {134-142}, doi = {10.1093/molbev/msv202}, pmid = {26416979}, issn = {1537-1719}, mesh = {Animals ; Bees/*genetics/*physiology ; Cell Death/genetics ; Female ; Infertility/*genetics ; Oogenesis/genetics ; Social Behavior ; }, abstract = {Worker sterility is a defining characteristic of eusociality. The existence of the sterile worker caste remains a fundamental question for evolutionary biology as it requires the existence of genes that reduce personal reproduction. Currently, little is known about the proximate mechanisms underpinning worker sterility. Studies into a mutant "anarchistic" strain (in which workers can activate their ovaries) of honey bee, Apis mellifera, identified a list of candidate genes that regulate ovary activation. We quantified the expression of the four most promising candidate genes (Anarchy, Pdk1, S6k, and Ulk3) in nonactivated and activated ovaries of wild-type workers. Ovarian expression of Anarchy, a peroxisomal membrane protein, predicts the ovary state of workers with 88.2% accuracy. Increased expression of Anarchy in the ovary is strongly associated with suppression of oogenesis and its expression is sensitive to the presence of the queen. Therefore, Anarchy satisfies key criteria for a "gene underlying altruism". When we knocked down expression of Anarchy in the ovary using RNA interference (RNAi) we altered the expression of Buffy, a gene that regulates programmed cell death. Whole-mount multiplex fluorescent in situ hybridization (mFISH) shows Anarchy transcripts localize to degenerating oocytes within the ovary. Our results suggest that Anarchy is involved in the regulation of oogenesis through programmed cell death. The evolution of facultative worker sterility most likely occurred when the conserved mechanism of programmed cell death was co-opted to regulate ovary activation. Anarchy may therefore be the first example of a gene that has evolved through kin selection to regulate worker sterility.}, } @article {pmid26410832, year = {2015}, author = {Dudley, SA}, title = {Plant cooperation.}, journal = {AoB PLANTS}, volume = {7}, number = {}, pages = {}, pmid = {26410832}, issn = {2041-2851}, abstract = {The study of plant behaviour will be aided by conceptual approaches and terminology for cooperation, altruism and helping. The plant literature has a rich discussion of helping between species while the animal literature has an extensive and somewhat contentious discussion of within-species helping. Here, I identify and synthesize concepts, terminology and some practical methodology for speaking about helping in plant populations and measuring the costs and benefits. I use Lehmann and Keller's (2006) classification scheme for animal helping and McIntire and Fajardo's (2014) synthesis of facilitation to provide starting points for classifying the mechanisms of how and why organisms help each other. Contextual theory is discussed as a mechanism for understanding and measuring the fitness consequences of helping. I synthesize helping into four categories. The act of helping can be costly to the helper. If the helper gains indirect fitness by helping relatives but loses direct fitness, this is altruism, and it only occurs within species. Helpers can exchange costly help, which is called mutualism when between species, and reciprocation when within a species. The act of helping can directly benefit the helper as well as the recipient, either as an epiphenomenon resulting from behaviours under natural selection for other reasons, or because the helper is creating a mutual benefit, such as satiating predators or supporting a mutualism. Facilitation between species by stress amelioration, creation of novel ecosystems and habitat complexity often meets the definition of epiphenomenon helping. Within species, this kind of helping is called by-product mutualism. If the helping is under selection to create a mutual benefit shared by others, between species this is facilitation with service sharing or access to resources and within species, direct benefits by mutual benefits. These classifications provide a clear starting point for addressing the subject of helping behaviours.}, } @article {pmid26400743, year = {2015}, author = {Downing, PA and Cornwallis, CK and Griffin, AS}, title = {Sex, long life and the evolutionary transition to cooperative breeding in birds.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1816}, pages = {20151663}, pmid = {26400743}, issn = {1471-2954}, mesh = {Animals ; *Biological Evolution ; Birds/*physiology ; *Cooperative Behavior ; Female ; *Genetic Fitness ; Helping Behavior ; *Longevity ; Male ; Models, Biological ; *Nesting Behavior ; }, abstract = {Long life is a typical feature of individuals living in cooperative societies. One explanation is that group living lowers mortality, which selects for longer life. Alternatively, long life may make the evolution of cooperation more likely by ensuring a long breeding tenure, making helping behaviour and queuing for breeding positions worthwhile. The benefit of queuing will, however, depend on whether individuals gain indirect fitness benefits while helping, which is determined by female promiscuity. Where promiscuity is high and therefore the indirect fitness benefits of helping are low, cooperation can still be favoured by an even longer life span. We present the results of comparative analyses designed to test the likelihood of a causal relationship between longevity and cooperative breeding by reconstructing ancestral states of cooperative breeding across birds, and by examining the effect of female promiscuity on the relationship between these two traits. We found that long life makes the evolution of cooperation more likely and that promiscuous cooperative species are exceptionally long lived. These results make sense of promiscuity in cooperative breeders and clarify the importance of life-history traits in the evolution of cooperative breeding, illustrating that cooperation can evolve via the combination of indirect and direct fitness benefits.}, } @article {pmid26379365, year = {2015}, author = {Pfefferle, D and Ruiz-Lambides, AV and Widdig, A}, title = {Male rhesus macaques use vocalizations to distinguish female maternal, but not paternal, kin from non-kin.}, journal = {Behavioral ecology and sociobiology}, volume = {69}, number = {10}, pages = {1677-1686}, pmid = {26379365}, issn = {0340-5443}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {Recognizing close kin and adjusting one's behavior accordingly (i.e., favor kin in social interactions, but avoid mating with them) would be an important skill that can increase an animals' inclusive fitness. Previous studies showed that philopatric female rhesus macaques (Macaca mulatta) bias their social behavior toward maternal and paternal kin. Benefits gained from selecting kin should, however, not only apply to the philopatric sex, for which the enduring spatial proximity facilitates kin discrimination. Given that dispersal is costly, the dispersing sex may benefit from migrating together with their kin or into groups containing kin. In male rhesus macaques, natal migrants bias their spatial proximity toward familiar male kin rather than familiar non-kin. Here, we set up playback experiments to test if males use the acoustic modality to discriminate familiar female kin from non-kin in a non-sexual context. Males responded differently to the presentation of "coo" calls of related and unrelated females, with their reaction depending on the interaction between kin-line (maternal vs paternal kin) and degree of relatedness (r = 0.5, 0.25). Specifically, males were more likely to respond to close kin compared to more distant kin or unrelated females, with this effect being significant in the maternal, but not paternal kin-line. The present study adds to our knowledge of kin recognition abilities of the dispersing sex, suggesting that male rhesus macaques are also able to identify kin using the acoustic modality. We discuss that the probability of response might be affected by the potential benefit of the social partner.}, } @article {pmid26374636, year = {2015}, author = {van Hateren, JH}, title = {Extensive fitness and human cooperation.}, journal = {Theory in biosciences = Theorie in den Biowissenschaften}, volume = {134}, number = {3-4}, pages = {127-142}, pmid = {26374636}, issn = {1611-7530}, mesh = {*Biological Evolution ; *Competitive Behavior ; *Cooperative Behavior ; Genetic Fitness/*genetics ; *Genetics, Population ; Humans ; *Models, Genetic ; }, abstract = {Evolution depends on the fitness of organisms, the expected rate of reproducing. Directly getting offspring is the most basic form of fitness, but fitness can also be increased indirectly by helping genetically related individuals (such as kin) to increase their fitness. The combined effect is known as inclusive fitness. Here it is argued that a further elaboration of fitness has evolved, particularly in humans. It is called extensive fitness and it incorporates producing organisms that are merely similar in phenotype. The evolvability of this mechanism is illustrated by computations on a simple model combining heredity and behaviour. Phenotypes are driven into the direction of high fitness through a mechanism that involves an internal estimate of fitness, implicitly made within the organism itself. This mechanism has recently been conjectured to be responsible for producing agency and goals. In the model, inclusive and extensive fitness are both implemented by letting fitness increase nonlinearly with the size of subpopulations of similar heredity (for the indirect part of inclusive fitness) and of similar phenotype (for the phenotypic part of extensive fitness). Populations implementing extensive fitness outcompete populations implementing mere inclusive fitness. This occurs because groups with similar phenotype tend to be larger than groups with similar heredity, and fitness increases more when groups are larger. Extensive fitness has two components, a direct component where individuals compete in inducing others to become like them and an indirect component where individuals cooperate and help others who are already similar to them.}, } @article {pmid26367536, year = {2015}, author = {Langos, D and Kulik, L and Ruiz-Lambides, A and Widdig, A}, title = {Does Male Care, Provided to Immature Individuals, Influence Immature Fitness in Rhesus Macaques?.}, journal = {PloS one}, volume = {10}, number = {9}, pages = {e0137841}, pmid = {26367536}, issn = {1932-6203}, support = {P40 OD012217/OD/NIH HHS/United States ; }, mesh = {Adipose Tissue ; Animals ; Behavior, Animal ; Body Weight ; *Fathers ; Macaca mulatta/genetics/*physiology ; Male ; Mothers ; Organ Size ; Puerto Rico ; Sexual Maturation ; Testis/growth & development ; }, abstract = {Among many mammals, maternal care strongly impacts infant survival; however, less is known about whether adult males also affect infant fitness. Paternal care is expected when providing care enhances offspring survival and reproduction, which likewise increases fathers' fitness. Males might also care for unrelated immature individuals to increase their mating probability with the immature individuals' mothers. Studies in multimale primate groups showed that sires enhance food access for offspring and provide protection in conflicts. Furthermore, fathers' presence during infancy has been suggested to accelerate offspring sexual maturation. However, no study has yet directly linked the degree of father-offspring bonds to offspring fitness in primates. We previously reported father-offspring affiliation in rhesus macaques, pronounced during early infancy and independent of mothers' presence. The present study aims at investigating whether affiliation with fathers or other males affects proxies of immature fitness (body mass gain, body fat and testis size). First, we combined behavioral, genetic and morphometric data from 55 subjects of one group. Second, using demographic and genetic data, we investigated for 92 individuals of the population whether mother- and father-offspring co-residence during immaturity influenced offspring lifetime reproductive success (LRS). Our results show that focal rank and higher amounts of affiliation with high-ranking males during infancy tend to positively impact body mass gain of female, but not male focal animals. In contrast, body mass gain of male focal individuals, but not females', appeared to be higher when affiliation of male immature individuals was evenly distributed across their adult male partners. Moreover, we found mothers', but not fathers', presence during immaturity to predict offspring LRS. Our results suggest that male-immature affiliation, but not father-offspring co-residence, potentially impacts proxies of immature fitness. However, future studies should investigate the underlying mechanisms of male-immature relationships and their impact on immature fitness in more detail.}, } @article {pmid26365471, year = {2016}, author = {Till-Bottraud, I and de Villemereuil, P}, title = {Kin recognition or phenotype matching?.}, journal = {The New phytologist}, volume = {209}, number = {1}, pages = {13-14}, doi = {10.1111/nph.13554}, pmid = {26365471}, issn = {1469-8137}, mesh = {Arabidopsis/*physiology ; Arabidopsis Proteins/*metabolism ; Photoreceptors, Plant/*metabolism ; }, } @article {pmid26353400, year = {2015}, author = {Provorov, NA and Vorohyov, NI}, title = {[Evolution of Host-Beneficial Traits in Nitrogen-Fixing Bacteria: Modeling and Construction of Systems for Interspecies Altruism].}, journal = {Prikladnaia biokhimiia i mikrobiologiia}, volume = {51}, number = {4}, pages = {363-370}, pmid = {26353400}, issn = {0555-1099}, mesh = {Bacteria/genetics/*metabolism ; *Biological Evolution ; Fabaceae/genetics/*metabolism ; Nitrogen/metabolism ; Nitrogen Fixation/*genetics ; Phenotype ; Rhizobium/metabolism/physiology ; Symbiosis/genetics ; }, abstract = {The literature and our own data on N2-fixing bacteria forming symbioses with plants and providing convenient models to study the evolution of interspecies (microsymbionts --> hosts) altruism are considered in the review. It is presented as a deeply reorganized intraspecies altruism implemented in the clonal population of rhizobia (bacteroids --> undifferentiated bacteria) under the control of kin selection induced by plant hosts. The analysis of this model suggests that it is possible to engineer practically valuable rhizobial strains in which high N2-fixing activity is combined with decreased survival outside of plants.}, } @article {pmid26334186, year = {2015}, author = {Arnberg, NN and Shizuka, D and Chaine, AS and Lyon, BE}, title = {Social network structure in wintering golden-crowned sparrows is not correlated with kinship.}, journal = {Molecular ecology}, volume = {24}, number = {19}, pages = {5034-5044}, doi = {10.1111/mec.13366}, pmid = {26334186}, issn = {1365-294X}, mesh = {Animal Migration ; Animals ; *Behavior, Animal ; Microsatellite Repeats ; Models, Genetic ; Seasons ; *Social Behavior ; Sparrows/*genetics ; }, abstract = {Stable social organization in a wide variety of organisms has been linked to kinship, which can minimize conflict due to the indirect fitness benefits from cooperating with relatives. In birds, kin selection has been mostly studied in the context of reproduction or in species that are social year round. Many birds however are migratory, and the role of kinship in the winter societies of these species is virtually unexplored. In a previous study, we discovered striking social complexity and stability in a wintering population of migratory golden-crowned sparrows (Zonotrichia atricapilla) - individuals repeatedly form close associations with the same social partners, including across multiple winters. Here, we test the possibility that kinship might be involved in these close and stable social affiliations. We examine the relationship between kinship and social structure for two of the consecutive wintering seasons from the previous study. We found no evidence that social structure was influenced by kinship. Relatedness between most pairs of individuals was at most that of first cousins (and mostly far lower). Genetic networks based on relatedness do not correspond to the social networks, and Mantel tests revealed no relationship between kinship and pairwise interaction frequency. Kinship also failed to predict social structure in more fine-grained analyses, including analyses of each sex separately (in the event that sex-biased migration might limit kin selection to one sex), and separate analyses for each social community. The complex winter societies of golden-crowned sparrows appear to be based on cooperative benefits unrelated to kin selection.}, } @article {pmid26317249, year = {2015}, author = {James, RN}, title = {Exploration-exploitation: A cognitive dilemma still unresolved.}, journal = {Cognitive neuroscience}, volume = {6}, number = {4}, pages = {219-221}, doi = {10.1080/17588928.2015.1051012}, pmid = {26317249}, issn = {1758-8936}, mesh = {Choice Behavior/*physiology ; Decision Making/*physiology ; Humans ; }, abstract = {The solution to the exploration-exploitation dilemma presented essentially subsumes exploitation into an information-maximizing model. Such a single-maximization model is shown to be (1) more tractable than the initial dual-maximization dilemma, (2) useful in modeling information-maximizing subsystems, and (3) profitably applied in artificial simulations where exploration is costless. However, the model fails to resolve the dilemma in ethological or practical circumstances with objective outcomes, such as inclusive fitness, rather than information outcomes, such as lack of surprise.}, } @article {pmid26306167, year = {2015}, author = {Carazo, P and Perry, JC and Johnson, F and Pizzari, T and Wigby, S}, title = {Related male Drosophila melanogaster reared together as larvae fight less and sire longer lived daughters.}, journal = {Ecology and evolution}, volume = {5}, number = {14}, pages = {2787-2797}, pmid = {26306167}, issn = {2045-7758}, support = {BB/K014544/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {Competition over access to reproductive opportunities can lead males to harm females. However, recent work has shown that, in Drosophila melanogaster, male competition and male harm of females are both reduced under conditions simulating male-specific population viscosity (i.e., in groups where males are related and reared with each other as larvae). Here, we seek to replicate these findings and investigate whether male population viscosity can have repercussions for the fitness of offspring in the next generation. We show that groups of unrelated-unfamiliar (i.e., unrelated individuals raised apart) males fight more intensely than groups of related-familiar males (i.e., full siblings raised together as larvae), supporting previous findings, and that exposure to a female is required to trigger these differential patterns of male-male competition. Importantly, we show that differences in male-male competition can be associated with transgenerational effects: the daughters of females exposed to unrelated-unfamiliar males suffered higher mortality than the daughters of females exposed to related-familiar males. Collectively, these results suggest that population structure (i.e., variation in the relatedness and/or larval familiarity of local male groups) can modulate male-male competition with important transgenerational consequences.}, } @article {pmid26299423, year = {2015}, author = {Hesse, S and Anaya-Rojas, JM and Frommen, JG and Thünken, T}, title = {Kinship reinforces cooperative predator inspection in a cichlid fish.}, journal = {Journal of evolutionary biology}, volume = {28}, number = {11}, pages = {2088-2096}, doi = {10.1111/jeb.12736}, pmid = {26299423}, issn = {1420-9101}, mesh = {Animals ; Cichlids/*genetics ; *Cooperative Behavior ; Female ; Genetic Fitness ; Male ; *Predatory Behavior ; }, abstract = {Kin selection theory predicts that cooperation is facilitated between genetic relatives, as by cooperating with kin an individual might increase its inclusive fitness. Although numerous theoretical papers support Hamilton's inclusive fitness theory, experimental evidence is still underrepresented, in particular in noncooperative breeders. Cooperative predator inspection is one of the most intriguing antipredator strategies, as it implies high costs on inspectors. During an inspection event, one or more individuals leave the safety of a group and approach a potential predator to gather information about the current predation risk. We investigated the effect of genetic relatedness on cooperative predator inspection in juveniles of the cichlid fish Pelvicachromis taeniatus, a species in which juveniles live in shoals under natural conditions. We show that relatedness significantly influenced predator inspection behaviour with kin dyads being significantly more cooperative. Thus, our results indicate a higher disposition for cooperative antipredator behaviour among kin as predicted by kin selection theory.}, } @article {pmid26288141, year = {2015}, author = {Michel, ES and Demarais, S and Strickland, BK and Belant, JL}, title = {Contrasting the Effects of Maternal and Behavioral Characteristics on Fawn Birth Mass in White-Tailed Deer.}, journal = {PloS one}, volume = {10}, number = {8}, pages = {e0136034}, pmid = {26288141}, issn = {1932-6203}, mesh = {Animals ; Animals, Newborn ; *Biobehavioral Sciences ; Birth Weight/*physiology ; Body Mass Index ; Deer ; Female ; Hierarchy, Social ; Male ; Maternal Age ; Maternal Behavior/*psychology ; }, abstract = {Maternal care influences offspring quality and can improve a mother's inclusive fitness. However, improved fitness may only occur when offspring quality (i.e., offspring birth mass) persists throughout life and enhances survival and/or reproductive success. Although maternal body mass, age, and social rank have been shown to influence offspring birth mass, the inter-dependence among these variables makes identifying causation problematic. We established that fawn birth mass was related to adult body mass for captive male and female white-tailed deer (Odocoileus virginianus), thus maternal care should improve offspring fitness. We then used path analysis to identify which maternal characteristic(s) most influenced fawn birth mass of captive female white-tailed deer. Maternal age, body mass and social rank had varying effects on fawn birth mass. Maternal body mass displayed the strongest direct effect on fawn birth mass, followed by maternal age and social rank. Maternal body mass had a greater effect on social rank than age. The direct path between social rank and fawn birth mass may indicate dominance as an underlying mechanism. Our results suggest that heavier mothers could use dominance to improve access to resources, resulting in increased fitness through production of heavier offspring.}, } @article {pmid26284738, year = {2015}, author = {Furness, AI and Morrison, KR and Orr, TJ and Arendt, JD and Reznick, DN}, title = {Reproductive mode and the shifting arenas of evolutionary conflict.}, journal = {Annals of the New York Academy of Sciences}, volume = {1360}, number = {}, pages = {75-100}, doi = {10.1111/nyas.12835}, pmid = {26284738}, issn = {1749-6632}, mesh = {Animals ; *Biological Evolution ; *Conflict, Psychological ; Family Relations/*psychology ; Female ; Humans ; Male ; Reproduction/*physiology ; }, abstract = {In sexually reproducing organisms, the genetic interests of individuals are not perfectly aligned. Conflicts among family members are prevalent since interactions involve the transfer of limited resources between interdependent players. Intrafamilial conflict has traditionally been considered along three major axes: between the sexes, between parents and offspring, and between siblings. In these interactions, conflict is expected over traits in which the resulting phenotypic value is determined by multiple family members who have only partially overlapping fitness optima. We focus on four major categories of animal reproductive mode (broadcast spawning, egg laying, live bearing, and live bearing with matrotrophy) and identify the shared phenotypes or traits over which conflict is expected, and then review the empirical literature for evidence of their occurrence. Major transitions among reproductive mode, such as a shift from external to internal fertilization, an increase in egg-retention time, modifications of embryos and mothers for nutrient transfer, the evolution of postnatal parental care, and increased interaction with the kin network, mark key shifts that both change and expand the arenas in which conflict is played out.}, } @article {pmid26276684, year = {2015}, author = {Tan, K and Wang, Y and Dong, S and Liu, X and Zhuang, D and Chen, W and Oldroyd, BP}, title = {Associations between reproduction and work in workers of the Asian hive bee Apis cerana.}, journal = {Journal of insect physiology}, volume = {82}, number = {}, pages = {33-37}, doi = {10.1016/j.jinsphys.2015.08.003}, pmid = {26276684}, issn = {1879-1611}, mesh = {Animals ; *Appetitive Behavior ; Bees/growth & development/*physiology ; Female ; Male ; Ovary/growth & development ; Plant Nectar ; Pollen ; Reproduction/physiology ; *Social Behavior ; }, abstract = {If a honey bee (Apis spp.) colony becomes queenless, about 1/3 of young workers activate their ovaries and produce haploid male-producing eggs. In doing so queenless workers maximize their inclusive fitness because the normal option of vicarious production of relatives via their queen's eggs is no longer available. But if many workers are engaged in reproduction, how does a queenless colony continue to feed its brood and forage? Here we show that in the Asian hive bee Apis cerana hypopharyngeal gland (HPG) size is larger in queenless workers than in queenright workers and that bees undertaking brood-rearing tasks have larger HPG than same-aged bees that are foraging. In queenless colonies, workers with a smaller number of ovarioles are more likely to have activated ovaries. This reinforces the puzzling observation that a large number of ovarioles reduces reproductive success in queenless A. cerana. It further suggests that reproductive workers either avoid foraging or transition to foraging later in life than non-reproductive workers. Finally, our study also showed that ovary activation and larger-than-average numbers of ovarioles had no statistically detectable influence on foraging specialization for pollen or nectar.}, } @article {pmid26269501, year = {2015}, author = {Chippindale, AK and Berggren, M and Alpern, JH and Montgomerie, R}, title = {Does kin selection moderate sexual conflict in Drosophila?.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1813}, pages = {20151417}, pmid = {26269501}, issn = {1471-2954}, mesh = {Animals ; Conflict, Psychological ; Drosophila melanogaster/genetics/*physiology ; Female ; Male ; *Sexual Behavior, Animal ; }, abstract = {Two recent studies provide provocative experimental findings about the potential influence of kin recognition and cooperation on the level of sexual conflict in Drosophila melanogaster. In both studies, male fruit flies apparently curbed their mate-harming behaviours in the presence of a few familiar or related males, suggesting some form of cooperation mediated by kin selection. In one study, the reduction in agonistic behaviour by brothers apparently rendered them vulnerable to dramatic loss of paternity share when competing with an unrelated male. If these results are robust and generalizable, fruit flies could be a major new focus for the experimental study of kin selection and social evolution. In our opinion, however, the restrictive conditions required for male cooperation to be adaptive in this species make it unlikely to evolve. We investigated these phenomena in two different populations of D. melanogaster using protocols very similar to those in the two previous studies. Our experiments show no evidence for a reduction in mate harm based upon either relatedness or familiarity between males, and no reduction in male reproductive success when two brothers are in the presence of an unfamiliar, unrelated, 'foreign' male. Thus, the reduction of sexual conflict owing to male cooperation does not appear to be a general feature of the species, at least under domestication, and these contrasting results call for further investigation: in new populations, in the field and in the laboratory populations in which these phenomena have been reported.}, } @article {pmid26265012, year = {2015}, author = {Goodnight, CJ}, title = {Multilevel selection theory and evidence: a critique of Gardner, 2015.}, journal = {Journal of evolutionary biology}, volume = {28}, number = {9}, pages = {1734-1746}, doi = {10.1111/jeb.12685}, pmid = {26265012}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Gardner (2015) recently developed a model of a 'Genetical Theory of Multilevel Selection, which is a thoughtfully developed, but flawed model. The model's flaws appear to be symptomatic of common misunderstandings of the multi level selection (MLS) literature and the recent quantitative genetic literature. I use Gardner's model as a guide for highlighting how the MLS literature can address the misconceptions found in his model, and the kin selection literature in general. I discuss research on the efficacy of group selection, the roll of indirect genetic effects in affecting the response to selection and the heritability of group-level traits. I also discuss why the Price multilevel partition should not be used to partition MLS, and why contextual analysis and, by association, direct fitness are appropriate for partitioning MLS. Finally, I discuss conceptual issues around questions concerning the level at which fitness is measured, the units of selection, and I present a brief outline of a model of selection in class-structured populations. I argue that the results derived from the MLS research tradition can inform kin selection research and models, and provide insights that will allow researchers to avoid conceptual flaws such as those seen in the Gardner model.}, } @article {pmid26263233, year = {2015}, author = {Troisi, A}, title = {The evolutionary diagnosis of mental disorder.}, journal = {Wiley interdisciplinary reviews. Cognitive science}, volume = {6}, number = {3}, pages = {323-331}, doi = {10.1002/wcs.1339}, pmid = {26263233}, issn = {1939-5086}, mesh = {Adaptation, Psychological ; *Biological Evolution ; Diagnostic and Statistical Manual of Mental Disorders ; Humans ; Mental Disorders/classification/*diagnosis ; Psychiatry ; }, abstract = {Medicalization of human behavioral diversity is a recurrent theme in the history of psychiatry, and the problem of defining what is a genuine mental disorder is an unresolved question since the origins of clinical psychopathology. Darwinian psychiatry can formulate a definition of mental disorder that is value free and based on factual criteria. From an evolutionary perspective, genuine mental disorders are maladaptive conditions. The ultimate function of an adaptation is gene propagation via maximization of survival and reproduction. It follows that a distressing and/or disabling psychological or behavioral syndrome is a psychiatric disorder only if it impacts negatively on the individual's inclusive fitness. However, in many cases, an evolutionary definition of disorder cannot be reconciled with current social values. Thus, clinicians adopting the evolutionary approach should conform to the prevailing trend of contemporary medicine and accept that their task is to be healers of the distressed, not watchdogs of biological adaptation. These pragmatic considerations do not minimize the scientific validity of the Darwinian definition of mental disorders. Probably, its major contribution to psychiatric theory is the elimination of the necessity to find a brain lesion or dysfunctional mechanism to validate the distinction between disorders and non-disorders.}, } @article {pmid26258950, year = {2015}, author = {Bowers, EK and Forsman, AM and Masters, BS and Johnson, BG and Johnson, LS and Sakaluk, SK and Thompson, CF}, title = {Increased extra-pair paternity in broods of aging males and enhanced recruitment of extra-pair young in a migratory bird.}, journal = {Evolution; international journal of organic evolution}, volume = {69}, number = {9}, pages = {2533-2541}, pmid = {26258950}, issn = {1558-5646}, support = {R15 HD076308/HD/NICHD NIH HHS/United States ; R15HD076308-01/HD/NICHD NIH HHS/United States ; }, mesh = {*Aging ; Animal Migration ; Animals ; Behavior, Animal ; Female ; Male ; *Mating Preference, Animal ; Phytohemagglutinins/immunology ; Reproduction/*physiology ; Skin/immunology ; Songbirds/immunology/*physiology ; }, abstract = {Despite keen interest in extra-pair mating in birds, its adaptive significance remains unresolved. Here, we use a multi-year dataset to test whether traits of a female's social mate influence her propensity to produce extra-pair offspring in a population of house wrens, and whether producing extra-pair young has consequences for a female's fitness through effects on offspring survival. Females were most likely to produce extra-pair offspring when paired with old males and when paired with males on poor-quality territories, although this latter effect was marginally nonsignificant. Among offspring, the cutaneous immunity of within-pair young decreased as the age of their sires increased, but cutaneous immunity of extra-pair young was not affected by the age of their extra-pair sires or by the age of the males rearing them. Extra-pair offspring were more likely than within-pair offspring to return as breeding adults to the local population, with extra-pair sons being more likely to return as a breeder for multiple years. Our findings support the hypothesis that females produce extra-pair offspring to enhance their inclusive fitness beyond what they are capable of given the male with which they are socially paired.}, } @article {pmid26238365, year = {2015}, author = {Bourke, AF}, title = {Sex investment ratios in eusocial Hymenoptera support inclusive fitness theory.}, journal = {Journal of evolutionary biology}, volume = {28}, number = {11}, pages = {2106-2111}, doi = {10.1111/jeb.12710}, pmid = {26238365}, issn = {1420-9101}, mesh = {Animals ; Female ; Genetic Fitness/*genetics/physiology ; Hymenoptera/genetics/*physiology ; Male ; *Sex Ratio ; *Social Behavior ; }, abstract = {Inclusive fitness theory predicts that sex investment ratios in eusocial Hymenoptera are a function of the relatedness asymmetry (relative relatedness to females and males) of the individuals controlling sex allocation. In monogynous ants (with one queen per colony), assuming worker control, the theory therefore predicts female-biased sex investment ratios, as found in natural populations. Recently, E.O. Wilson and M.A. Nowak criticized this explanation and presented an alternative hypothesis. The Wilson-Nowak sex ratio hypothesis proposes that, in monogynous ants, there is selection for a 1 : 1 numerical sex ratio to avoid males remaining unmated, which, given queens exceed males in size, results in a female-biased sex investment ratio. The hypothesis also asserts that, contrary to inclusive fitness theory, queens not workers control sex allocation and queen-worker conflict over sex allocation is absent. Here, I argue that the Wilson-Nowak sex ratio hypothesis is flawed because it contradicts Fisher's sex ratio theory, which shows that selection on sex ratio does not maximize the number of mated offspring and that the sex ratio proposed by the hypothesis is not an equilibrium for the queen. In addition, the hypothesis is not supported by empirical evidence, as it fails to explain 'split' (bimodal) sex ratios or data showing queen and worker control and ongoing queen-worker conflict. By contrast, these phenomena match predictions of inclusive fitness theory. Hence, the Wilson-Nowak sex ratio hypothesis fails both as an alternative hypothesis for sex investment ratios in eusocial Hymenoptera and as a critique of inclusive fitness theory.}, } @article {pmid26190034, year = {2015}, author = {Faria, GS and Varela, SA and Gardner, A}, title = {Sex-biased dispersal, kin selection and the evolution of sexual conflict.}, journal = {Journal of evolutionary biology}, volume = {28}, number = {10}, pages = {1901-1910}, doi = {10.1111/jeb.12697}, pmid = {26190034}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; *Conflict, Psychological ; Female ; Humans ; Male ; *Sexual Behavior ; }, abstract = {There is growing interest in resolving the curious disconnect between the fields of kin selection and sexual selection. Rankin's (2011, J. Evol. Biol. 24, 71-81) theoretical study of the impact of kin selection on the evolution of sexual conflict in viscous populations has been particularly valuable in stimulating empirical research in this area. An important goal of that study was to understand the impact of sex-specific rates of dispersal upon the coevolution of male-harm and female-resistance behaviours. But the fitness functions derived in Rankin's study do not flow from his model's assumptions and, in particular, are not consistent with sex-biased dispersal. Here, we develop new fitness functions that do logically flow from the model's assumptions, to determine the impact of sex-specific patterns of dispersal on the evolution of sexual conflict. Although Rankin's study suggested that increasing male dispersal always promotes the evolution of male harm and that increasing female dispersal always inhibits the evolution of male harm, we find that the opposite can also be true, depending upon parameter values.}, } @article {pmid26179800, year = {2015}, author = {Pollack, L and Rubenstein, DR}, title = {The fitness consequences of kin-biased dispersal in a cooperatively breeding bird.}, journal = {Biology letters}, volume = {11}, number = {7}, pages = {}, pmid = {26179800}, issn = {1744-957X}, mesh = {Animal Migration ; Animals ; *Cooperative Behavior ; Female ; Male ; Microsatellite Repeats ; Nesting Behavior ; Reproduction/physiology ; Sexual Behavior, Animal ; Social Behavior ; Starlings/genetics/*physiology ; }, abstract = {Cooperative alliances among kin may not only lead to indirect fitness benefits for group-living species, but can also provide direct benefits through access to mates or higher social rank. However, the immigrant sex in most species loses any potential benefits of living with kin unless immigrants disperse together or recruit relatives into the group in subsequent years. To look for evidence of small subgroups of related immigrants within social groups (kin substructure), we used microsatellites to assess relatedness between immigrant females of the cooperatively breeding superb starling, Lamprotornis superbus. We determined how timing of immigration led to kin subgroup formation and if being part of one influenced female fitness. Although mean relatedness in groups was higher for males than females, 26% of immigrant females were part of a kin subgroup with a sister. These immigrant sibships formed through kin recruitment across years more often than through coalitions immigrating together in the same year. Furthermore, females were more likely to breed when part of a kin subgroup than when alone, suggesting that female siblings form alliances that may positively influence their fitness. Ultimately, kin substructure should be considered when determining the role of relatedness in the evolution of animal societies.}, } @article {pmid26172866, year = {2015}, author = {van Dijk, RE and Covas, R and Doutrelant, C and Spottiswoode, CN and Hatchwell, BJ}, title = {Fine-scale genetic structure reflects sex-specific dispersal strategies in a population of sociable weavers (Philetairus socius).}, journal = {Molecular ecology}, volume = {24}, number = {16}, pages = {4296-4311}, doi = {10.1111/mec.13308}, pmid = {26172866}, issn = {1365-294X}, mesh = {Africa, Southern ; *Animal Distribution ; Animals ; Female ; *Genetics, Population ; Genotype ; Male ; Models, Genetic ; *Sexual Behavior, Animal ; Social Behavior ; Sparrows/*genetics ; Spatial Analysis ; }, abstract = {Dispersal is a critical driver of gene flow, with important consequences for population genetic structure, social interactions and other biological processes. Limited dispersal may result in kin-structured populations in which kin selection may operate, but it may also increase the risk of kin competition and inbreeding. Here, we use a combination of long-term field data and molecular genetics to examine dispersal patterns and their consequences for the population genetics of a highly social bird, the sociable weaver (Philetairus socius), which exhibits cooperation at various levels of sociality from nuclear family groups to its unique communal nests. Using 20 years of data, involving capture of 6508 birds and 3151 recaptures at 48 colonies, we found that both sexes exhibit philopatry and that any dispersal occurs over relatively short distances. Dispersal is female-biased, with females dispersing earlier, further, and to less closely related destination colonies than males. Genotyping data from 30 colonies showed that this pattern of dispersal is reflected by fine-scale genetic structure for both sexes, revealed by isolation by distance in terms of genetic relatedness and significant genetic variance among colonies. Both relationships were stronger among males than females. Crucially, significant relatedness extended beyond the level of the colony for both sexes. Such fine-scale population genetic structure may have played an important role in the evolution of cooperative behaviour in this species, but it may also result in a significant inbreeding risk, against which female-biased dispersal alone is unlikely to be an effective strategy.}, } @article {pmid26169539, year = {2015}, author = {Dunn, JD and Vujicic, T and Wild, G}, title = {Sex allocation and the emergence of helping in cooperatively breeding species.}, journal = {Theoretical population biology}, volume = {104}, number = {}, pages = {1-9}, doi = {10.1016/j.tpb.2015.06.006}, pmid = {26169539}, issn = {1096-0325}, mesh = {Animals ; *Biological Evolution ; *Breeding ; Cooperative Behavior ; Female ; Male ; Models, Biological ; Population Dynamics ; *Sex Determination Processes ; }, abstract = {In cooperative breeding systems individuals invest in the reproductive success of others. In this paper, we study the emergence of cooperative breeding systems in which reproductively active breeders receive investment from reproductively non-active helpers. Our goal is to understand how the division of an investment between male and female components of breeder fitness (i.e. the helper sex-allocation strategy) influences the emergence of cooperative breeding itself. Using mathematical models, we arrive at expressions for the inclusive-fitness advantage of helpful behaviour that generalize previous work. These expressions assume an ecologically stable environment, and that breeders make evolutionarily stable sex-allocation decisions. We find that, when breeders are extremely resource limited, the sex-allocation strategy used by a helper can be a key determinant in the success of helpful alleles. This finding, however, is restricted to cases in which helpers have access to intermediate levels of resources. Surprisingly, when helpers can make only a small investment in a recipient the division of the investment matters only very little to advantage of help. By contrast when resources are extremely abundant, we obtain the unsurprising result that the manner in which resources are allocated has little influence on the emergence of help. When breeders have access to intermediate levels of resources we find increasing relatedness can, in certain cases, inhibit the emergence of help. We also find that increasing the amount of resources available to a breeder can impede help as well. Both of these counter-intuitive results are mediated by evolutionary responses in breeder sex allocation.}, } @article {pmid26151588, year = {2015}, author = {Peña, J and Nöldeke, G and Lehmann, L}, title = {Evolutionary dynamics of collective action in spatially structured populations.}, journal = {Journal of theoretical biology}, volume = {382}, number = {}, pages = {122-136}, doi = {10.1016/j.jtbi.2015.06.039}, pmid = {26151588}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Cooperative Behavior ; Family ; Humans ; Interpersonal Relations ; Models, Theoretical ; *Population Dynamics ; }, abstract = {Many models proposed to study the evolution of collective action rely on a formalism that represents social interactions as n-player games between individuals adopting discrete actions such as cooperate and defect. Despite the importance of spatial structure in biological collective action, the analysis of n-player games games in spatially structured populations has so far proved elusive. We address this problem by considering mixed strategies and by integrating discrete-action n-player games into the direct fitness approach of social evolution theory. This allows to conveniently identify convergence stable strategies and to capture the effect of population structure by a single structure coefficient, namely, the pairwise (scaled) relatedness among interacting individuals. As an application, we use our mathematical framework to investigate collective action problems associated with the provision of three different kinds of collective goods, paradigmatic of a vast array of helping traits in nature: "public goods" (both providers and shirkers can use the good, e.g., alarm calls), "club goods" (only providers can use the good, e.g., participation in collective hunting), and "charity goods" (only shirkers can use the good, e.g., altruistic sacrifice). We show that relatedness promotes the evolution of collective action in different ways depending on the kind of collective good and its economies of scale. Our findings highlight the importance of explicitly accounting for relatedness, the kind of collective good, and the economies of scale in theoretical and empirical studies of the evolution of collective action.}, } @article {pmid26139329, year = {2015}, author = {Levréro, F and Carrete-Vega, G and Herbert, A and Lawabi, I and Courtiol, A and Willaume, E and Kappeler, PM and Charpentier, MJ}, title = {Social shaping of voices does not impair phenotype matching of kinship in mandrills.}, journal = {Nature communications}, volume = {6}, number = {}, pages = {7609}, pmid = {26139329}, issn = {2041-1723}, mesh = {*Acoustics ; Altruism ; Animals ; *Behavior, Animal ; Cooperative Behavior ; Gabon ; Mandrillus ; *Phenotype ; *Recognition, Psychology ; *Social Behavior ; Social Perception ; Vocalization, Animal/*physiology ; }, abstract = {Kin selection theory provides a strong theoretical framework to explain the evolution of altruism and cooperative behaviour among genetically related individuals. However, the proximate mechanisms underlying kin discrimination, a necessary process to express kin-related behaviour, remain poorly known. In particular, no study has yet unambiguously disentangled mechanisms based on learned familiarity from true phenotype matching in kin discrimination based on vocal signals. Here we show that in addition to genetic background, social accommodation also shapes individual voices in an Old World monkey (Mandrillus sphinx), even though primate vocalizations were thought to be innate and little flexible. Nonetheless, social shaping of voice parameters does not impair kin discrimination through phenotype-matching of unknown relatives, revealing unexpected discriminatory versatility despite signal complexity. Accurate signal production and perception, therefore, provide a basis for kin identification and kin-biased behaviour in an Old World primate.}, } @article {pmid26132515, year = {2016}, author = {Camperio Ciani, A and Battaglia, U and Liotta, M}, title = {Societal Norms Rather Than Sexual Orientation Influence Kin Altruism and Avuncularity in Tribal Urak-Lawoi, Italian, and Spanish Adult Males.}, journal = {Journal of sex research}, volume = {53}, number = {2}, pages = {137-148}, doi = {10.1080/00224499.2014.993748}, pmid = {26132515}, issn = {1559-8519}, mesh = {Adult ; *Altruism ; Family Relations/*ethnology ; Heterosexuality/*ethnology ; Homosexuality, Male/*ethnology ; Humans ; Italy/ethnology ; Male ; Spain/ethnology ; Thailand/ethnology ; Young Adult ; }, abstract = {Homosexual males could balance their low fitness by increasing benefits to relatives either through kin-directed altruism or by avuncularity (altruistic behavior toward the children of siblings). Evidence in support of kin selection and avuncularity includes the fact that homosexuals seem to be more empathic and altruistic than heterosexuals. Other studies have not confirmed behaviors that increase kin altruism in homosexuals. We explored altruistic behavior and avuncularity in a sample of 278 subjects, either homosexual or heterosexual, from three populations: Italian, Spanish, and Urak-Lawoi, a Southeast Asian tribal population. Among the Urak-Lawoi, the kathoeys, androphilic men who dress and behave as women, were compared with heterosexuals. All populations were rated for societal norms on the expression of affiliative behavior. No greater kin altruism or avuncularity among the kathoeys or in homosexuals in either Mediterranean population was found. Greater avuncularity and kin-directed altruism, independent of sexual orientation, were found among the Urak-Lawoi, and these traits were the least prevalent among the Italians, corresponding to different societal norms. The increase in kin altruism and avuncularity was associated in all males with societal differences and norms on general altruism toward nonkin children, suggesting it is not an adaptive design to maintain homosexuality in humans.}, } @article {pmid26100180, year = {2015}, author = {Tekwa, EW and Gonzalez, A and Loreau, M}, title = {Local densities connect spatial ecology to game, multilevel selection and inclusive fitness theories of cooperation.}, journal = {Journal of theoretical biology}, volume = {380}, number = {}, pages = {414-425}, doi = {10.1016/j.jtbi.2015.06.016}, pmid = {26100180}, issn = {1095-8541}, mesh = {*Cooperative Behavior ; *Game Theory ; *Models, Theoretical ; }, abstract = {Cooperation plays a crucial role in many aspects of biology. We use the spatial ecological metrics of local densities to measure and model cooperative interactions. While local densities can be found as technical details in current theories, we aim to establish them as central to an approach that describes spatial effects in the evolution of cooperation. A resulting local interaction model neatly partitions various spatial and non-spatial selection mechanisms. Furthermore, local densities are shown to be fundamental for important metrics of game theory, multilevel selection theory and inclusive fitness theory. The corresponding metrics include structure coefficients, spatial variance, contextual covariance, relatedness, and inbreeding coefficient or F-statistics. Local densities serve as the basis of an emergent spatial theory that draws from and brings unity to multiple theories of cooperation.}, } @article {pmid26086267, year = {2015}, author = {Liu, M and Zhong, QD and Cheng, YR and Li, SH and Fang, S and Pu, CE and Yuan, HW and Shen, SF}, title = {The Genetic Relatedness in Groups of Joint-Nesting Taiwan Yuhinas: Low Genetic Relatedness with Preferences for Male Kin.}, journal = {PloS one}, volume = {10}, number = {6}, pages = {e0127341}, pmid = {26086267}, issn = {1932-6203}, mesh = {Animals ; Breeding ; Cooperative Behavior ; *Evolution, Molecular ; Female ; Male ; *Nesting Behavior ; Passeriformes/*genetics ; Pedigree ; *Phylogeny ; }, abstract = {The relative importance of direct and indirect fitness and, thus, the role of kinship in the evolution of social behavior is much debated. Studying the genetic relatedness of interacting individuals is crucial to improving our understanding of these issues. Here, we used a seven-year data set to study the genetic structure of the Taiwan yuhina (Yuhina brunneciceps), a joint-nesting passerine. Ten microsatellite loci were used to investigate the pair-wised relatedness among yuhina breeding group members. We found that the average genetic relatedness between same-sex group members was very low (0.069 for male dyads and 0.016 for female dyads). There was also a low ratio of closely-related kin (r>0.25) in the cooperative breeding groups of yuhinas (21.59% and 9.68% for male and female dyads, respectively). However, the relatedness of male dyads within breeding groups was significantly higher than female dyads. Our results suggest that yuhina cooperation is maintained primarily by direct fitness benefits to individuals; however, kin selection might play a role in partner choice for male yuhinas. Our study also highlights an important, but often neglected, question: Why do animals form non-kin groups, if kin are available? We use biological market theory to propose an explanation for group formation of unrelated Taiwan yuhinas.}, } @article {pmid26085590, year = {2015}, author = {Rodrigues, AM and Gardner, A}, title = {Simultaneous failure of two sex-allocation invariants: implications for sex-ratio variation within and between populations.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1810}, pages = {}, pmid = {26085590}, issn = {1471-2954}, mesh = {Animal Distribution ; Animals ; *Biological Evolution ; Female ; *Fertility ; Male ; Models, Biological ; Reproduction ; Selection, Genetic ; *Sex Ratio ; Sexual Behavior, Animal ; }, abstract = {Local mate competition (LMC) occurs when male relatives compete for mating opportunities, and this may favour the evolution of female-biased sex allocation. LMC theory is among the most well developed and empirically supported topics in behavioural ecology, clarifies links between kin selection, group selection and game theory, and provides among the best quantitative evidence for Darwinian adaptation in the natural world. Two striking invariants arise from this body of work: the number of sons produced by each female is independent of both female fecundity and also the rate of female dispersal. Both of these invariants have stimulated a great deal of theoretical and empirical research. Here, we show that both of these invariants break down when variation in female fecundity and limited female dispersal are considered in conjunction. Specifically, limited dispersal of females following mating leads to local resource competition (LRC) between female relatives for breeding opportunities, and the daughters of high-fecundity mothers experience such LRC more strongly than do those of low-fecundity mothers. Accordingly, high-fecundity mothers are favoured to invest relatively more in sons, while low-fecundity mothers are favoured to invest relatively more in daughters, and the overall sex ratio of the population sex ratio becomes more female biased as a result.}, } @article {pmid26082379, year = {2015}, author = {Lehmann, L and Alger, I and Weibull, J}, title = {Does evolution lead to maximizing behavior?.}, journal = {Evolution; international journal of organic evolution}, volume = {69}, number = {7}, pages = {1858-1873}, doi = {10.1111/evo.12701}, pmid = {26082379}, issn = {1558-5646}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; Game Theory ; *Genetic Fitness ; Models, Genetic ; *Social Behavior ; }, abstract = {A long-standing question in biology and economics is whether individual organisms evolve to behave as if they were striving to maximize some goal function. We here formalize this "as if" question in a patch-structured population in which individuals obtain material payoffs from (perhaps very complex multimove) social interactions. These material payoffs determine personal fitness and, ultimately, invasion fitness. We ask whether individuals in uninvadable population states will appear to be maximizing conventional goal functions (with population-structure coefficients exogenous to the individual's behavior), when what is really being maximized is invasion fitness at the genetic level. We reach two broad conclusions. First, no simple and general individual-centered goal function emerges from the analysis. This stems from the fact that invasion fitness is a gene-centered multigenerational measure of evolutionary success. Second, when selection is weak, all multigenerational effects of selection can be summarized in a neutral type-distribution quantifying identity-by-descent between individuals within patches. Individuals then behave as if they were striving to maximize a weighted sum of material payoffs (own and others). At an uninvadable state it is as if individuals would freely choose their actions and play a Nash equilibrium of a game with a goal function that combines self-interest (own material payoff), group interest (group material payoff if everyone does the same), and local rivalry (material payoff differences).}, } @article {pmid26079367, year = {2015}, author = {Hargreaves, AL and Bailey, SF and Laird, RA}, title = {Fitness declines towards range limits and local adaptation to climate affect dispersal evolution during climate-induced range shifts.}, journal = {Journal of evolutionary biology}, volume = {28}, number = {8}, pages = {1489-1501}, doi = {10.1111/jeb.12669}, pmid = {26079367}, issn = {1420-9101}, mesh = {*Adaptation, Physiological ; Biological Evolution ; Climate Change ; *Ecosystem ; *Genetic Fitness ; Genotype ; *Models, Biological ; Temperature ; }, abstract = {Dispersal ability will largely determine whether species track their climatic niches during climate change, a process especially important for populations at contracting (low-latitude/low-elevation) range limits that otherwise risk extinction. We investigate whether dispersal evolution at contracting range limits is facilitated by two processes that potentially enable edge populations to experience and adjust to the effects of climate deterioration before they cause extinction: (i) climate-induced fitness declines towards range limits and (ii) local adaptation to a shifting climate gradient. We simulate a species distributed continuously along a temperature gradient using a spatially explicit, individual-based model. We compare range-wide dispersal evolution during climate stability vs. directional climate change, with uniform fitness vs. fitness that declines towards range limits (RLs), and for a single climate genotype vs. multiple genotypes locally adapted to temperature. During climate stability, dispersal decreased towards RLs when fitness was uniform, but increased when fitness declined towards RLs, due to highly dispersive genotypes maintaining sink populations at RLs, increased kin selection in smaller populations, and an emergent fitness asymmetry that favoured dispersal in low-quality habitat. However, this initial dispersal advantage at low-fitness RLs did not facilitate climate tracking, as it was outweighed by an increased probability of extinction. Locally adapted genotypes benefited from staying close to their climate optima; this selected against dispersal under stable climates but for increased dispersal throughout shifting ranges, compared to cases without local adaptation. Dispersal increased at expanding RLs in most scenarios, but only increased at the range centre and contracting RLs given local adaptation to climate.}, } @article {pmid26063846, year = {2015}, author = {Adams, MJ and Robinson, MR and Mannarelli, ME and Hatchwell, BJ}, title = {Social genetic and social environment effects on parental and helper care in a cooperatively breeding bird.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1810}, pages = {}, pmid = {26063846}, issn = {1471-2954}, mesh = {Animals ; *Cooperative Behavior ; England ; Female ; Male ; *Nesting Behavior ; Reproduction ; Seasons ; *Social Environment ; Songbirds/genetics/*physiology ; }, abstract = {Phenotypes expressed in a social context are not only a function of the individual, but can also be shaped by the phenotypes of social partners. These social effects may play a major role in the evolution of cooperative breeding if social partners differ in the quality of care they provide and if individual carers adjust their effort in relation to that of other carers. When applying social effects models to wild study systems, it is also important to explore sources of individual plasticity that could masquerade as social effects. We studied offspring provisioning rates of parents and helpers in a wild population of long-tailed tits Aegithalos caudatus using a quantitative genetic framework to identify these social effects and partition them into genetic, permanent environment and current environment components. Controlling for other effects, individuals were consistent in their provisioning effort at a given nest, but adjusted their effort based on who was in their social group, indicating the presence of social effects. However, these social effects differed between years and social contexts, indicating a current environment effect, rather than indicating a genetic or permanent environment effect. While this study reveals the importance of examining environmental and genetic sources of social effects, the framework we present is entirely general, enabling a greater understanding of potentially important social effects within any ecological population.}, } @article {pmid26061705, year = {2015}, author = {Miller, S and Knowles, J}, title = {Population Fluctuation Promotes Cooperation in Networks.}, journal = {Scientific reports}, volume = {5}, number = {}, pages = {11054}, pmid = {26061705}, issn = {2045-2322}, mesh = {*Cooperative Behavior ; *Game Theory ; Humans ; *Models, Theoretical ; }, abstract = {We consider the problem of explaining the emergence and evolution of cooperation in dynamic network-structured populations. Building on seminal work by Poncela et al., which shows how cooperation (in one-shot prisoner's dilemma) is supported in growing populations by an evolutionary preferential attachment (EPA) model, we investigate the effect of fluctuations in the population size. We find that a fluctuating model - based on repeated population growth and truncation - is more robust than Poncela et al.'s in that cooperation flourishes for a wider variety of initial conditions. In terms of both the temptation to defect, and the types of strategies present in the founder network, the fluctuating population is found to lead more securely to cooperation. Further, we find that this model will also support the emergence of cooperation from pre-existing non-cooperative random networks. This model, like Poncela et al.'s, does not require agents to have memory, recognition of other agents, or other cognitive abilities, and so may suggest a more general explanation of the emergence of cooperation in early evolutionary transitions, than mechanisms such as kin selection, direct and indirect reciprocity.}, } @article {pmid26056358, year = {2015}, author = {Brown, JS and Aktipis, CA}, title = {Inclusive fitness effects can select for cancer suppression into old age.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {370}, number = {1673}, pages = {}, pmid = {26056358}, issn = {1471-2970}, support = {1U54 CA143970-01/CA/NCI NIH HHS/United States ; R01 CA170595/CA/NCI NIH HHS/United States ; }, mesh = {Aging ; Animals ; Biological Evolution ; Breeding ; Cooperative Behavior ; Female ; Fertility ; Genetic Fitness ; Humans ; Male ; *Models, Biological ; Neoplasms/etiology/*prevention & control ; Reproduction ; Selection, Genetic ; }, abstract = {Natural selection can favour health at youth or middle age (high reproductive value) over health at old age (low reproductive value). This means, all else being equal, selection for cancer suppression should dramatically drop after reproductive age. However, in species with significant parental investment, the capacity to enhance inclusive fitness may increase the reproductive value of older individuals or even those past reproductive age. Variation in parental investment levels could therefore contribute to variation in cancer susceptibility across species. In this article, we describe a simple model and framework for the evolution of cancer suppression with varying levels of parental investment and use this model to make testable predictions about variation in cancer suppression across species. This model can be extended to show that selection for cancer suppression is stronger in species with cooperative breeding systems and intergenerational transfers. We consider three cases that can select for cancer suppression into old age: (i) extended parental care that increases the survivorship of their offspring, (ii) grandparents contributing to higher fecundity of their children and (iii) cooperative breeding where helpers forgo reproduction or even survivorship to assist parents in having higher fecundity.}, } @article {pmid26052783, year = {2015}, author = {Zurita-Gutiérrez, YH and Lion, S}, title = {Spatial structure, host heterogeneity and parasite virulence: implications for vaccine-driven evolution.}, journal = {Ecology letters}, volume = {18}, number = {8}, pages = {779-789}, doi = {10.1111/ele.12455}, pmid = {26052783}, issn = {1461-0248}, mesh = {*Biological Evolution ; Genetics, Population ; Host-Pathogen Interactions/*genetics ; *Models, Biological ; *Vaccines ; Virulence/genetics ; }, abstract = {Natural host-parasite interactions exhibit considerable variation in host quality, with profound consequences for disease ecology and evolution. For instance, treatments (such as vaccination) may select for more transmissible or virulent strains. Previous theory has addressed the ecological and evolutionary impact of host heterogeneity under the assumption that hosts and parasites disperse globally. Here, we investigate the joint effects of host heterogeneity and local dispersal on the evolution of parasite life-history traits. We first formalise a general theoretical framework combining variation in host quality and spatial structure. We then apply this model to the specific problem of parasite evolution following vaccination. We show that, depending on the type of vaccine, spatial structure may select for higher or lower virulence compared to the predictions of non-spatial theory. We discuss the implications of our results for disease management, and their broader fundamental relevance for other causes of host heterogeneity in nature.}, } @article {pmid26048562, year = {2015}, author = {Kocher, SD and Tsuruda, JM and Gibson, JD and Emore, CM and Arechavaleta-Velasco, ME and Queller, DC and Strassmann, JE and Grozinger, CM and Gribskov, MR and San Miguel, P and Westerman, R and Hunt, GJ}, title = {A Search for Parent-of-Origin Effects on Honey Bee Gene Expression.}, journal = {G3 (Bethesda, Md.)}, volume = {5}, number = {8}, pages = {1657-1662}, pmid = {26048562}, issn = {2160-1836}, mesh = {Alleles ; Animals ; Bees/*genetics/growth & development/metabolism ; Brain/metabolism ; Crossing Over, Genetic ; Female ; *Gene Expression ; Genetic Linkage ; Genotype ; Larva/metabolism ; Male ; Polymorphism, Single Nucleotide ; }, abstract = {Parent-specific gene expression (PSGE) is little known outside of mammals and plants. PSGE occurs when the expression level of a gene depends on whether an allele was inherited from the mother or the father. Kin selection theory predicts that there should be extensive PSGE in social insects because social insect parents can gain inclusive fitness benefits by silencing parental alleles in female offspring. We searched for evidence of PSGE in honey bees using transcriptomes from reciprocal crosses between European and Africanized strains. We found 46 transcripts with significant parent-of-origin effects on gene expression, many of which overexpressed the maternal allele. Interestingly, we also found a large proportion of genes showing a bias toward maternal alleles in only one of the reciprocal crosses. These results indicate that PSGE may occur in social insects. The nonreciprocal effects could be largely driven by hybrid incompatibility between these strains. Future work will help to determine if these are indeed parent-of-origin effects that can modulate inclusive fitness benefits.}, } @article {pmid26031601, year = {2016}, author = {Widdig, A and Kessler, MJ and Bercovitch, FB and Berard, JD and Duggleby, C and Nürnberg, P and Rawlins, RG and Sauermann, U and Wang, Q and Krawczak, M and Schmidtke, J}, title = {Genetic studies on the Cayo Santiago rhesus macaques: A review of 40 years of research.}, journal = {American journal of primatology}, volume = {78}, number = {1}, pages = {44-62}, doi = {10.1002/ajp.22424}, pmid = {26031601}, issn = {1098-2345}, support = {P40-RR-01293/RR/NCRR NIH HHS/United States ; P40-RR-03640/RR/NCRR NIH HHS/United States ; RR-712003/RR/NCRR NIH HHS/United States ; RR-72115/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Genetics/*history ; History, 20th Century ; History, 21st Century ; Macaca mulatta/*genetics ; Puerto Rico ; }, abstract = {Genetic studies not only contribute substantially to our current understanding of the natural variation in behavior and health in many species, they also provide the basis of numerous in vivo models of human traits. Despite the many challenges posed by the high level of biological and social complexity, a long lifespan and difficult access in the field, genetic studies of primates are particularly rewarding because of the close evolutionary relatedness of these species to humans. The free-ranging rhesus macaque (Macaca mulatta) population on Cayo Santiago (CS), Puerto Rico, provides a unique resource in this respect because several of the abovementioned caveats are of either minor importance there, or lacking altogether, thereby allowing long-term genetic research in a primate population under constant surveillance since 1956. This review summarizes more than 40 years of genetic research carried out on CS, from early blood group typing and the genetic characterization of skeletal material via population-wide paternity testing with DNA fingerprints and short tandem repeats (STRs) to the analysis of the highly polymorphic DQB1 locus within the major histocompatibility complex (MHC). The results of the paternity studies also facilitated subsequent studies of male dominance and other factors influencing male reproductive success, of male reproductive skew, paternal kin bias, and mechanisms of paternal kin recognition. More recently, the CS macaques have been the subjects of functional genetic and gene expression analyses and have played an important role in behavioral and quantitative genetic studies. In addition, the CS colony has been used as a natural model for human adult-onset macular degeneration, glaucoma, and circadian rhythm disorder. Our review finishes off with a discussion of potential future directions of research on CS, including the transition from STRs to single nucleotide polymorphism (SNP) typing and whole genome sequencing.}, } @article {pmid26030734, year = {2015}, author = {Wilder, B and Stanley, KO}, title = {Altruists Proliferate Even at a Selective Disadvantage within Their Own Niche.}, journal = {PloS one}, volume = {10}, number = {6}, pages = {e0128654}, pmid = {26030734}, issn = {1932-6203}, mesh = {*Altruism ; Computer Simulation ; *Evolution, Molecular ; Genetics, Population/methods ; Models, Genetic ; Selection, Genetic/*genetics ; }, abstract = {The evolutionary origin of altruism is a long-standing puzzle. Numerous explanations have been proposed, most prominently based on inclusive fitness or group selection. One possibility that has not yet been considered is that new niches will be created disproportionately often when altruism appears, perhaps by chance, causing altruists to be over-represented in such new niches. This effect is a novel variant of group selection in which altruistic groups benefit by discovering unoccupied niches instead of by competing for the limited resources within a single niche. Both an analytical population genetics model and computational simulations support that altruism systematically arises due to this side effect of increased carrying capacity even when it is strongly selected against within any given niche. In fact, even when selection is very strongly negative and altruism does not develop in most populations, it can still be expected to be observed in a consistent fraction of species. The ecological structure provided by niches thereby may be sufficient for altruists to proliferate even if they are always at a disadvantage within each niche considered individually.}, } @article {pmid26022302, year = {2015}, author = {Parga, JA and Sauther, ML and Cuozzo, FP and Youssouf Jacky, IA and Gould, L and Sussman, RW and Lawler, RR and Pastorini, J}, title = {Genetic Evidence for Male and Female Dispersal in Wild Lemur catta.}, journal = {Folia primatologica; international journal of primatology}, volume = {86}, number = {1-2}, pages = {66-75}, doi = {10.1159/000369386}, pmid = {26022302}, issn = {1421-9980}, mesh = {*Animal Distribution ; Animals ; Competitive Behavior ; Female ; Gene Flow ; Lemur/*genetics/physiology/psychology ; Madagascar ; Male ; Microsatellite Repeats ; Sex Factors ; Social Behavior ; }, abstract = {Lemur catta has traditionally been considered a species with male-biased dispersal; however, occasional female dispersal occurs. Using molecular data, we evaluated dispersal patterns in 2 L. catta populations in southwestern Madagascar: Tsimanampesotse National Park (TNP) and Bezà Mahafaly Special Reserve (BMSR). We also investigated the genetic differentiation between the populations and dispersal partner relatedness. Results showed minor genetic differentiation between the populations (ϴ(ST) = 0.039), which may indicate gene flow historically occurring in this region, made possible by the presence of L. catta groups between the sites. Different patterns of sex-biased dispersal were found between the sites using corrected assignment indices: male-biased dispersal in TNP, and a lack of sex-biased dispersal in BMSR. Observational evidence of female dispersal in BMSR supports these results and may imply intense female resource competition in and around BMSR, because small groups of 2-3 females have been observed dispersing within BMSR and entering the reserve from outside. These dispersing groups largely consisted of mothers transferring with daughters, although we have an aunt-niece pair transferring together. Genetic data suggest that males also transfer with relatives. Our data demonstrate that dispersal partners consist of same-sexed kin for L. catta males and females, highlighting the importance of kin selection.}, } @article {pmid26003630, year = {2015}, author = {Van Cleve, J}, title = {Social evolution and genetic interactions in the short and long term.}, journal = {Theoretical population biology}, volume = {103}, number = {}, pages = {2-26}, doi = {10.1016/j.tpb.2015.05.002}, pmid = {26003630}, issn = {1096-0325}, mesh = {*Biological Evolution ; Genetics, Population ; *Social Behavior ; }, abstract = {The evolution of social traits remains one of the most fascinating and feisty topics in evolutionary biology even after half a century of theoretical research. W.D. Hamilton shaped much of the field initially with his 1964 papers that laid out the foundation for understanding the effect of genetic relatedness on the evolution of social behavior. Early theoretical investigations revealed two critical assumptions required for Hamilton's rule to hold in dynamical models: weak selection and additive genetic interactions. However, only recently have analytical approaches from population genetics and evolutionary game theory developed sufficiently so that social evolution can be studied under the joint action of selection, mutation, and genetic drift. We review how these approaches suggest two timescales for evolution under weak mutation: (i) a short-term timescale where evolution occurs between a finite set of alleles, and (ii) a long-term timescale where a continuum of alleles are possible and populations evolve continuously from one monomorphic trait to another. We show how Hamilton's rule emerges from the short-term analysis under additivity and how non-additive genetic interactions can be accounted for more generally. This short-term approach reproduces, synthesizes, and generalizes many previous results including the one-third law from evolutionary game theory and risk dominance from economic game theory. Using the long-term approach, we illustrate how trait evolution can be described with a diffusion equation that is a stochastic analogue of the canonical equation of adaptive dynamics. Peaks in the stationary distribution of the diffusion capture classic notions of convergence stability from evolutionary game theory and generally depend on the additive genetic interactions inherent in Hamilton's rule. Surprisingly, the peaks of the long-term stationary distribution can predict the effects of simple kinds of non-additive interactions. Additionally, the peaks capture both weak and strong effects of social payoffs in a manner difficult to replicate with the short-term approach. Together, the results from the short and long-term approaches suggest both how Hamilton's insight may be robust in unexpected ways and how current analytical approaches can expand our understanding of social evolution far beyond Hamilton's original work.}, } @article {pmid25983360, year = {2015}, author = {Kulik, L and Amici, F and Langos, D and Widdig, A}, title = {Sex Differences in the Development of Social Relationships in Rhesus Macaques (Macaca mulatta).}, journal = {International journal of primatology}, volume = {36}, number = {2}, pages = {353-376}, pmid = {25983360}, issn = {0164-0291}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {Several studies have documented the importance of social bonding for the enhancement of individual fitness. However, little is known about how social relationships develop through ontogeny, and whether their development follows the same trajectory in males and females. Here we analyzed affiliative interactions (proximity, social grooming, play) combined with demographic and genetic data in semi-free-ranging rhesus macaques (Macaca mulatta) on Cayo Santiago over their first 4 yr of life (from birth to sexual maturation) to understand how these interactions change through development in both sexes. Generalized linear mixed models revealed that social behaviors mostly followed different developmental trajectories in males and females and were highly dependent on the social context. In particular, sex differences in social behavior varied through development depending on the partner's sex and age. Females engaged in more social interactions than males, especially with other females, and were more involved in grooming around the time of maturation. In contrast, males interacted more with males and age peers, especially around maturation. Sex differences in social behavior varied through development, but also depended on rank, partner's rank, and kin line, although not consistently. High-ranking individuals, especially older females, were generally preferred as social partners. Moreover, both male and female individuals interacted mostly with maternal kin, although males also preferred paternal kin over nonkin. Importantly, most developmental changes in sociality happened when individuals were ca. 2 yr old, suggesting that this might be a milestone in the development of sociality in rhesus macaques. The only notable exception to this pattern was play, which was more pronounced in males from the beginning of their lives. We propose that play might serve as a trigger of sex differences in social behavior, with sex differences emerging early in development and increasing through time as males and females gradually grow into their adult social roles.}, } @article {pmid25982154, year = {2015}, author = {Croft, DP and Brent, LJ and Franks, DW and Cant, MA}, title = {The evolution of prolonged life after reproduction.}, journal = {Trends in ecology & evolution}, volume = {30}, number = {7}, pages = {407-416}, doi = {10.1016/j.tree.2015.04.011}, pmid = {25982154}, issn = {1872-8383}, mesh = {Aging/*physiology ; Animals ; *Biological Evolution ; Female ; Humans ; Longevity/*physiology ; Reproduction/physiology ; }, abstract = {Why females of some species cease ovulation before the end of their natural lifespan is a longstanding evolutionary puzzle. For many species in captivity, post-reproductive life is simply an epiphenomenon of lengthened lifespan. Yet in natural populations of humans as well as some cetaceans and insects, reproductive senescence occurs much faster than somatic aging and females exhibit prolonged post-reproductive lifespans (PRLSs). Determining the mechanisms and functions that underpin PRLSs has proved a significant challenge. Here we bring together both classic and modern hypotheses proposed to explain PRLSs and discuss their application to both human and nonhuman animals. By taking an integrative and broad taxonomic approach we highlight the need to consider multiple interacting explanations for the evolution of PRLSs.}, } @article {pmid25979121, year = {2015}, author = {Wang, Z and Kokubo, S and Jusup, M and Tanimoto, J}, title = {Universal scaling for the dilemma strength in evolutionary games.}, journal = {Physics of life reviews}, volume = {14}, number = {}, pages = {1-30}, doi = {10.1016/j.plrev.2015.04.033}, pmid = {25979121}, issn = {1873-1457}, mesh = {Animals ; *Biological Evolution ; Cooperative Behavior ; *Game Theory ; Humans ; Models, Theoretical ; }, abstract = {Why would natural selection favor the prevalence of cooperation within the groups of selfish individuals? A fruitful framework to address this question is evolutionary game theory, the essence of which is captured in the so-called social dilemmas. Such dilemmas have sparked the development of a variety of mathematical approaches to assess the conditions under which cooperation evolves. Furthermore, borrowing from statistical physics and network science, the research of the evolutionary game dynamics has been enriched with phenomena such as pattern formation, equilibrium selection, and self-organization. Numerous advances in understanding the evolution of cooperative behavior over the last few decades have recently been distilled into five reciprocity mechanisms: direct reciprocity, indirect reciprocity, kin selection, group selection, and network reciprocity. However, when social viscosity is introduced into a population via any of the reciprocity mechanisms, the existing scaling parameters for the dilemma strength do not yield a unique answer as to how the evolutionary dynamics should unfold. Motivated by this problem, we review the developments that led to the present state of affairs, highlight the accompanying pitfalls, and propose new universal scaling parameters for the dilemma strength. We prove universality by showing that the conditions for an ESS and the expressions for the internal equilibriums in an infinite, well-mixed population subjected to any of the five reciprocity mechanisms depend only on the new scaling parameters. A similar result is shown to hold for the fixation probability of the different strategies in a finite, well-mixed population. Furthermore, by means of numerical simulations, the same scaling parameters are shown to be effective even if the evolution of cooperation is considered on the spatial networks (with the exception of highly heterogeneous setups). We close the discussion by suggesting promising directions for future research including (i) how to handle the dilemma strength in the context of co-evolution and (ii) where to seek opportunities for applying the game theoretical approach with meaningful impact.}, } @article {pmid25977962, year = {2015}, author = {Tanskanen, AO}, title = {Childlessness and investment in nieces, nephews, aunts and uncles in Finland.}, journal = {Journal of biosocial science}, volume = {47}, number = {3}, pages = {402-406}, doi = {10.1017/s0021932014000339}, pmid = {25977962}, issn = {1469-7599}, mesh = {Adult ; Child ; Family Relations/*psychology ; Female ; Finland ; Humans ; Mothers ; *Reproductive Behavior/psychology/statistics & numerical data ; }, abstract = {Kin selection theory predicts that individuals may increase their inclusive fitness by investing in their genetically related kin. In addition, according to the reproductive value hypothesis, individuals may increase their fitness more by investing in their kin in descending rather than ascending order. The present study uses the Generational Transmissions in Finland data collected in 2012 (n ¼ 601 women) and analyses whether childless younger women invest more in their kin than younger women with children. The study finds that childless women are more likely than mothers to invest in their nieces and nephews but not their aunts and uncles. Thus the results are in line with the reproductive value prediction.}, } @article {pmid25970624, year = {2015}, author = {King, WJ and Forsyth, DM and Coulson, G and Festa-Bianchet, M}, title = {Adoption in eastern grey kangaroos: a consequence of misdirected care?.}, journal = {PloS one}, volume = {10}, number = {5}, pages = {e0125182}, pmid = {25970624}, issn = {1932-6203}, mesh = {Adoption/*psychology ; Age Factors ; Animals ; Australia ; Female ; Macropodidae/genetics/*psychology ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; Seasons ; }, abstract = {Adoption is rare in animals and is usually attributed to kin selection. In a 6-year study of eastern grey kangaroos (Macropus giganteus), 11 of 326 juveniles were adopted. We detected eight adoptions by observing behavioural associations and nursing between marked mothers and young and three more by analysing the relatedness of mothers and young using microsatellite DNA. Four adoptions involved reciprocal switches and three were by mothers whose own pouch young were known to subsequently disappear. Adoptive mothers were not closely related to each other or to adoptees but adoptive mothers and young associated as closely as did biological pairs, as measured by half-weight indices. Switch mothers did not associate closely. Maternal age and body condition did not influence the likelihood of adoption but females were more likely to adopt in years with high densities of females with large pouch young. Adoption did not improve juvenile survival. We conclude that adoptions in this wild population were potentially costly and likely caused by misdirected care, suggesting that eastern grey kangaroos may have poorly developed mother-offspring recognition mechanisms.}, } @article {pmid25953388, year = {2015}, author = {Allen, B and Nowak, MA}, title = {Games among relatives revisited.}, journal = {Journal of theoretical biology}, volume = {378}, number = {}, pages = {103-116}, doi = {10.1016/j.jtbi.2015.04.031}, pmid = {25953388}, issn = {1095-8541}, mesh = {*Biological Evolution ; Cooperative Behavior ; Family Relations/*psychology ; *Game Theory ; Humans ; *Models, Biological ; Population Density ; *Social Behavior ; }, abstract = {We present a simple model for the evolution of social behavior in family-structured, finite sized populations. Interactions are represented as evolutionary games describing frequency-dependent selection. Individuals interact more frequently with siblings than with members of the general population, as quantified by an assortment parameter r, which can be interpreted as "relatedness". Other models, mostly of spatially structured populations, have shown that assortment can promote the evolution of cooperation by facilitating interaction between cooperators, but this effect depends on the details of the evolutionary process. For our model, we find that sibling assortment promotes cooperation in stringent social dilemmas such as the Prisoner's Dilemma, but not necessarily in other situations. These results are obtained through straightforward calculations of changes in gene frequency. We also analyze our model using inclusive fitness. We find that the quantity of inclusive fitness does not exist for general games. For special games, where inclusive fitness exists, it provides less information than the straightforward analysis.}, } @article {pmid25914361, year = {2015}, author = {Kramer, KL and Russell, AF}, title = {Was monogamy a key step on the hominin road? Reevaluating the monogamy hypothesis in the evolution of cooperative breeding.}, journal = {Evolutionary anthropology}, volume = {24}, number = {2}, pages = {73-83}, doi = {10.1002/evan.21445}, pmid = {25914361}, issn = {1520-6505}, mesh = {Animals ; Anthropology, Physical ; *Biological Evolution ; Breeding ; Female ; Hominidae/*physiology ; Male ; Sexual Behavior, Animal/*physiology ; }, abstract = {Because human mothers routinely rely on others to help raise their young, humans have been characterized as cooperative breeders.(1-9) Several large-scale phylogenetic analyses have presented compelling evidence that monogamy preceded the evolution of cooperative breeding in a wide variety of nonhuman animals.(10-14) These studies have suggested that monogamy provides a general rule (the monogamy hypothesis) for explaining evolutionary transitions to cooperative breeding.(15) Given the prevalence of cooperative breeding in contemporary human societies, we evaluate whether this suggests a monogamous hominin past.}, } @article {pmid25909914, year = {2015}, author = {Nowak, MA and Allen, B}, title = {Inclusive fitness theorizing invokes phenomena that are not relevant for the evolution of eusociality.}, journal = {PLoS biology}, volume = {13}, number = {4}, pages = {e1002134}, pmid = {25909914}, issn = {1545-7885}, mesh = {Animals ; *Models, Theoretical ; *Social Behavior ; }, abstract = {In this Formal Comment, the authors challenge the claims of a recent theoretical study that genetic relatedness is important in the evolution of eusociality.}, } @article {pmid25909860, year = {2015}, author = {Queller, DC and Rong, S and Liao, X}, title = {Some agreement on kin selection and eusociality?.}, journal = {PLoS biology}, volume = {13}, number = {4}, pages = {e1002133}, pmid = {25909860}, issn = {1545-7885}, mesh = {Animals ; *Models, Theoretical ; *Social Behavior ; }, abstract = {The authors of "Relatedness, Conflict, and the Evolution of Eusociality" respond to objections raised by Martin Nowak and Benjamin Allen.}, } @article {pmid25909185, year = {2015}, author = {Duthie, AB and Reid, JM}, title = {What happens after inbreeding avoidance? Inbreeding by rejected relatives and the inclusive fitness benefit of inbreeding avoidance.}, journal = {PloS one}, volume = {10}, number = {4}, pages = {e0125140}, pmid = {25909185}, issn = {1932-6203}, mesh = {Animals ; Female ; Inbreeding/methods ; Male ; Mating Preference, Animal/*physiology ; Models, Biological ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; }, abstract = {Avoiding inbreeding, and therefore avoiding inbreeding depression in offspring fitness, is widely assumed to be adaptive in systems with biparental reproduction. However, inbreeding can also confer an inclusive fitness benefit stemming from increased relatedness between parents and inbred offspring. Whether or not inbreeding or avoiding inbreeding is adaptive therefore depends on a balance between inbreeding depression and increased parent-offspring relatedness. Existing models of biparental inbreeding predict threshold values of inbreeding depression above which males and females should avoid inbreeding, and predict sexual conflict over inbreeding because these thresholds diverge. However, these models implicitly assume that if a focal individual avoids inbreeding, then both it and its rejected relative will subsequently outbreed. We show that relaxing this assumption of reciprocal outbreeding, and the assumption that focal individuals are themselves outbred, can substantially alter the predicted thresholds for inbreeding avoidance for focal males. Specifically, the magnitude of inbreeding depression below which inbreeding increases a focal male's inclusive fitness increases with increasing depression in the offspring of a focal female and her alternative mate, and it decreases with increasing relatedness between a focal male and a focal female's alternative mate, thereby altering the predicted zone of sexual conflict. Furthermore, a focal male's inclusive fitness gain from avoiding inbreeding is reduced by indirect opportunity costs if his rejected relative breeds with another relative of his. By demonstrating that variation in relatedness and inbreeding can affect intra- and inter-sexual conflict over inbreeding, our models lead to novel predictions for family dynamics. Specifically, parent-offspring conflict over inbreeding might depend on the alternative mates of rejected relatives, and male-male competition over inbreeding might lead to mixed inbreeding strategies. Making testable quantitative predictions regarding inbreeding strategies occurring in nature will therefore require new models that explicitly capture variation in relatedness and inbreeding among interacting population members.}, } @article {pmid25900536, year = {2016}, author = {Alemu, SW and Berg, P and Janss, L and Bijma, P}, title = {Estimation of indirect genetic effects in group-housed mink (Neovison vison) should account for systematic interactions either due to kin or sex.}, journal = {Journal of animal breeding and genetics = Zeitschrift fur Tierzuchtung und Zuchtungsbiologie}, volume = {133}, number = {1}, pages = {43-50}, doi = {10.1111/jbg.12163}, pmid = {25900536}, issn = {1439-0388}, mesh = {Animals ; Body Weight ; Female ; Male ; Mink/*genetics/physiology ; Models, Genetic ; }, abstract = {Social interactions among individuals are abundant, both in wild and in domestic populations. With social interactions, the genes of an individual may affect the trait values of other individuals, a phenomenon known as indirect genetic effects (IGEs). IGEs can be estimated using linear mixed models. Most IGE models assume that individuals interact equally to all group mates irrespective of relatedness. Kin selection theory, however, predicts that an individual will interact differently with family members versus non-family members. Here, we investigate kin- and sex-specific non-genetic social interactions in group-housed mink. Furthermore, we investigated whether systematic non-genetic interactions between kin or individuals of the same sex influence the estimates of genetic parameters. As a second objective, we clarify the relationship between estimates of the traditional IGE model and a family-based IGE model proposed in a previous study. Our results indicate that male siblings in mink show different non-genetic interactions than female siblings in mink and that this may impact the estimation of genetic parameters. Moreover, we have shown how estimates from a family-based IGE model can be translated to the ordinary direct-indirect model and vice versa. We find no evidence for genetic differences in interactions among related versus unrelated mink.}, } @article {pmid25880586, year = {2015}, author = {Kölliker, M and Boos, S and Wong, JW and Röllin, L and Stucki, D and Raveh, S and Wu, M and Meunier, J}, title = {Parent-offspring conflict and the genetic trade-offs shaping parental investment.}, journal = {Nature communications}, volume = {6}, number = {}, pages = {6850}, pmid = {25880586}, issn = {2041-1723}, mesh = {Animals ; *Behavior, Animal ; Evolution, Molecular ; Female ; *Insecta ; Male ; *Maternal Behavior ; *Reproduction ; *Selection, Genetic ; }, abstract = {The genetic conflict between parents and their offspring is a cornerstone of kin selection theory and the gene-centred view of evolution, but whether it actually occurs in natural systems remains an open question. Conflict operates only if parenting is driven by genetic trade-offs between offspring performance and the parent's ability to raise additional offspring, and its expression critically depends on the shape of these trade-offs. Here we investigate the occurrence and nature of genetic conflict in an insect with maternal care, the earwig Forficula auricularia. Specifically, we test for a direct response to experimental selection on female future reproduction and correlated responses in current offspring survival, developmental rate and growth. The results demonstrate genetic trade-offs that differ in shape before and after hatching. Our study not only provides direct evidence for parent-offspring conflict but also highlights that conflict is not inevitable and critically depends on the genetic trade-offs shaping parental investment.}, } @article {pmid25810077, year = {2016}, author = {Widdig, A and Langos, D and Kulik, L}, title = {Sex differences in kin bias at maturation: Male rhesus macaques prefer paternal kin prior to natal dispersal.}, journal = {American journal of primatology}, volume = {78}, number = {1}, pages = {78-91}, doi = {10.1002/ajp.22401}, pmid = {25810077}, issn = {1098-2345}, support = {8 P40 OD012217-25/OD/NIH HHS/United States ; }, mesh = {*Animal Distribution ; Animals ; Female ; Macaca mulatta/genetics/*physiology ; Male ; Puerto Rico ; Sex Factors ; Sexual Maturation ; *Social Behavior ; }, abstract = {Dispersal and mating patterns are known to affect the availability of both maternal and paternal kin within social groups, with important effects on the evolution of sociality. It is generally assumed that the philopatric sex forms stronger social bonds than the dispersing sex, possibly as a result of reduced kin availability for the dispersing sex after departure. However, few primate studies have directly compared whether sex differences in association patterns, particular with kin, are already present prior to dispersal when kin availability should be the same for both sexes. Here, we compared affiliative and aggressive interactions in a female philopatric species, the rhesus macaque (Macaca mulatta), to test whether sex differences in kin bias already occur around the age of maturation, when both sexes still live together with kin in their natal group. Our data confirmed that kin availability was the same for both sexes prior to male dispersal. Similar kin availability was partially reflected by comparable association patterns, as both females and males preferentially interacted with maternal kin. However, females had stronger affiliative bonds with maternal kin than males of the same age, indicating that kin associations not only depended upon kin availability, but were also sex-specific. Similarly, males were significantly more likely to affiliate with paternal kin than non-kin, as compared to females, suggesting that males discriminated paternal kin from non-kin earlier in life than females. Males might have a stronger need than females to affiliate with paternal kin due to a reduced integration in the matrilineal family prior to dispersal and the high availability of paternally related age-peers, with whom males could potentially migrate. Females, in contrast, form stronger affiliations with maternal kin, which may enhance their offspring's survival. More comparative studies are needed to understand the impact of different dispersal regimes on patterns of kin associations.}, } @article {pmid25804868, year = {2015}, author = {Nonacs, P and Richards, MH}, title = {How (not) to review papers on inclusive fitness.}, journal = {Trends in ecology & evolution}, volume = {30}, number = {5}, pages = {235-237}, doi = {10.1016/j.tree.2015.02.007}, pmid = {25804868}, issn = {1872-8383}, mesh = {Altruism ; Animals ; *Biological Evolution ; Datasets as Topic ; *Genetic Fitness ; Humans ; Models, Genetic ; *Peer Review, Research ; Selection, Genetic ; Social Behavior ; }, } @article {pmid25799485, year = {2015}, author = {Liao, X and Rong, S and Queller, DC}, title = {Relatedness, conflict, and the evolution of eusociality.}, journal = {PLoS biology}, volume = {13}, number = {3}, pages = {e1002098}, pmid = {25799485}, issn = {1545-7885}, mesh = {Animals ; Ants/physiology ; Bees/physiology ; Behavior, Animal ; *Biological Evolution ; Genetic Fitness/*physiology ; Genetics, Population ; Isoptera/physiology ; *Models, Genetic ; Selection, Genetic ; *Sex Determination Processes ; *Social Behavior ; Wasps/physiology ; }, abstract = {The evolution of sterile worker castes in eusocial insects was a major problem in evolutionary theory until Hamilton developed a method called inclusive fitness. He used it to show that sterile castes could evolve via kin selection, in which a gene for altruistic sterility is favored when the altruism sufficiently benefits relatives carrying the gene. Inclusive fitness theory is well supported empirically and has been applied to many other areas, but a recent paper argued that the general method of inclusive fitness was wrong and advocated an alternative population genetic method. The claim of these authors was bolstered by a new model of the evolution of eusociality with novel conclusions that appeared to overturn some major results from inclusive fitness. Here we report an expanded examination of this kind of model for the evolution of eusociality and show that all three of its apparently novel conclusions are essentially false. Contrary to their claims, genetic relatedness is important and causal, workers are agents that can evolve to be in conflict with the queen, and eusociality is not so difficult to evolve. The misleading conclusions all resulted not from incorrect math but from overgeneralizing from narrow assumptions or parameter values. For example, all of their models implicitly assumed high relatedness, but modifying the model to allow lower relatedness shows that relatedness is essential and causal in the evolution of eusociality. Their modeling strategy, properly applied, actually confirms major insights of inclusive fitness studies of kin selection. This broad agreement of different models shows that social evolution theory, rather than being in turmoil, is supported by multiple theoretical approaches. It also suggests that extensive prior work using inclusive fitness, from microbial interactions to human evolution, should be considered robust unless shown otherwise.}, } @article {pmid25794651, year = {2015}, author = {Jansson, F}, title = {What games support the evolution of an ingroup bias?.}, journal = {Journal of theoretical biology}, volume = {373}, number = {}, pages = {100-110}, doi = {10.1016/j.jtbi.2015.03.008}, pmid = {25794651}, issn = {1095-8541}, mesh = {Algorithms ; *Biological Evolution ; Cooperative Behavior ; *Game Theory ; *Group Processes ; Humans ; Interpersonal Relations ; *Models, Genetic ; Selection, Genetic ; }, abstract = {There is an increasing wealth of models trying to explain the evolution of group discrimination and an ingroup bias. This paper sets out to systematically investigate the most fundamental assumption in these models: in what kind of situations do the interactions take place? What strategic structures - games - support the evolution of an ingroup bias? More specifically, the aim here is to find the prerequisites for when a bias also with respect to minimal groups - arbitrarily defined groups void of group-specific qualities - is selected for, and which cannot be ascribed to kin selection. Through analyses and simulations of minimal models of two-person games, this paper indicates that only some games are conducive to the evolution of ingroup favouritism. In particular, this class does not contain the prisoners׳ dilemma, but it does contain anti-co-ordination and co-ordination games. Contrasting to the prisoners׳ dilemma, these are games where it is not a matter of whether to behave altruistically, but rather one of predicting what the other person will be doing, and where I would benefit from you knowing my intentions. In anti-co-ordination games, on average, not only will agents discriminate between groups, but also in such a way that their choices maximise the sum of the available payoffs towards the ingroup more often than towards the outgroup. And in co-ordination games, even if agents do manage to co-ordinate with the whole population, they are more likely to co-ordinate on the socially optimal equilibrium within their group. Simulations show that this occurs most often in games where there is a component of risk-taking, and thus trust, involved. A typical such game is the stag hunt or assurance game.}, } @article {pmid25790030, year = {2015}, author = {Barton, NH and Servedio, MR}, title = {The interpretation of selection coefficients.}, journal = {Evolution; international journal of organic evolution}, volume = {69}, number = {5}, pages = {1101-1112}, doi = {10.1111/evo.12641}, pmid = {25790030}, issn = {1558-5646}, support = {250152/ERC_/European Research Council/International ; }, mesh = {Animals ; Female ; *Genetic Loci ; Male ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Evolutionary biologists have an array of powerful theoretical techniques that can accurately predict changes in the genetic composition of populations. Changes in gene frequencies and genetic associations between loci can be tracked as they respond to a wide variety of evolutionary forces. However, it is often less clear how to decompose these various forces into components that accurately reflect the underlying biology. Here, we present several issues that arise in the definition and interpretation of selection and selection coefficients, focusing on insights gained through the examination of selection coefficients in multilocus notation. Using this notation, we discuss how its flexibility-which allows different biological units to be identified as targets of selection-is reflected in the interpretation of the coefficients that the notation generates. In many situations, it can be difficult to agree on whether loci can be considered to be under "direct" versus "indirect" selection, or to quantify this selection. We present arguments for what the terms direct and indirect selection might best encompass, considering a range of issues, from viability and sexual selection to kin selection. We show how multilocus notation can discriminate between direct and indirect selection, and describe when it can do so.}, } @article {pmid25759717, year = {2015}, author = {Ruden, DM and Cingolani, PE and Sen, A and Qu, W and Wang, L and Senut, MC and Garfinkel, MD and Sollars, VE and Lu, X}, title = {Epigenetics as an answer to Darwin's "special difficulty," Part 2: natural selection of metastable epialleles in honeybee castes.}, journal = {Frontiers in genetics}, volume = {6}, number = {}, pages = {60}, pmid = {25759717}, issn = {1664-8021}, support = {P30 CA022453/CA/NCI NIH HHS/United States ; P30 ES020957/ES/NIEHS NIH HHS/United States ; R01 ES012933/ES/NIEHS NIH HHS/United States ; R21 ES021983/ES/NIEHS NIH HHS/United States ; }, abstract = {In a recent perspective in this journal, Herb (2014) discussed how epigenetics is a possible mechanism to circumvent Charles Darwin's "special difficulty" in using natural selection to explain the existence of the sterile-fertile dimorphism in eusocial insects. Darwin's classic book "On the Origin of Species by Means of Natural Selection" explains how natural selection of the fittest individuals in a population can allow a species to adapt to a novel or changing environment. However, in bees and other eusocial insects, such as ants and termites, there exist two or more castes of genetically similar females, from fertile queens to multiple sub-castes of sterile workers, with vastly different phenotypes, lifespans, and behaviors. This necessitates the selection of groups (or kin) rather than individuals in the evolution of honeybee hives, but group and kin selection theories of evolution are controversial and mechanistically uncertain. Also, group selection would seem to be prohibitively inefficient because the effective population size of a colony is reduced from thousands to a single breeding queen. In this follow-up perspective, we elaborate on possible mechanisms for how a combination of both epigenetics, specifically, the selection of metastable epialleles, and genetics, the selection of mutations generated by the selected metastable epialleles, allows for a combined means for selection amongst the fertile members of a species to increase colony fitness. This "intra-caste evolution" hypothesis is a variation of the epigenetic directed genetic error hypothesis, which proposes that selected metastable epialleles increase genetic variability by directing mutations specifically to the epialleles. Natural selection of random metastable epialleles followed by a second round of natural selection of random mutations generated by the metastable epialleles would allow a way around the small effective population size of eusocial insects.}, } @article {pmid25754636, year = {2015}, author = {Brent, LJN and Franks, DW and Foster, EA and Balcomb, KC and Cant, MA and Croft, DP}, title = {Ecological knowledge, leadership, and the evolution of menopause in killer whales.}, journal = {Current biology : CB}, volume = {25}, number = {6}, pages = {746-750}, doi = {10.1016/j.cub.2015.01.037}, pmid = {25754636}, issn = {1879-0445}, mesh = {Animals ; Behavior, Animal/physiology ; *Biological Evolution ; Diet ; Ecosystem ; Feeding Behavior/physiology ; Female ; Humans ; Learning ; Male ; Menopause/*physiology/*psychology ; Models, Biological ; Salmon ; Social Behavior ; Whale, Killer/*physiology/*psychology ; }, abstract = {Classic life-history theory predicts that menopause should not occur because there should be no selection for survival after the cessation of reproduction [1]. Yet, human females routinely live 30 years after they have stopped reproducing [2]. Only two other species-killer whales (Orcinus orca) and short-finned pilot whales (Globicephala macrorhynchus) [3, 4]-have comparable postreproductive lifespans. In theory, menopause can evolve via inclusive fitness benefits [5, 6], but the mechanisms by which postreproductive females help their kin remain enigmatic. One hypothesis is that postreproductive females act as repositories of ecological knowledge and thereby buffer kin against environmental hardships [7, 8]. We provide the first test of this hypothesis using a unique long-term dataset on wild resident killer whales. We show three key results. First, postreproductively aged females lead groups during collective movement in salmon foraging grounds. Second, leadership by postreproductively aged females is especially prominent in difficult years when salmon abundance is low. This finding is critical because salmon abundance drives both mortality and reproductive success in resident killer whales [9, 10]. Third, females are more likely to lead their sons than they are to lead their daughters, supporting predictions of recent models [5] of the evolution of menopause based on kinship dynamics. Our results show that postreproductive females may boost the fitness of kin through the transfer of ecological knowledge. The value gained from the wisdom of elders can help explain why female resident killer whales and humans continue to live long after they have stopped reproducing.}, } @article {pmid25750723, year = {2015}, author = {Hollis, B and Kawecki, TJ and Keller, L}, title = {No evidence that within-group male relatedness reduces harm to females in Drosophila.}, journal = {Ecology and evolution}, volume = {5}, number = {4}, pages = {979-983}, pmid = {25750723}, issn = {2045-7758}, abstract = {Conflict between males and females over whether, when, and how often to mate often leads to the evolution of sexually antagonistic interactions that reduce female reproductive success. Because the offspring of relatives contribute to inclusive fitness, high relatedness between rival males might be expected to reduce competition and result in the evolution of reduced harm to females. A recent study investigated this possibility in Drosophila melanogaster and concluded that groups of brothers cause less harm to females than groups of unrelated males, attributing the effect to kin selection. That study did not control for the rearing environment of males, rendering the results impossible to interpret in the context of kin selection. Here, we conducted a similar experiment while manipulating whether males developed with kin prior to being placed with females. We found no difference between related and unrelated males in the harm caused to females when males were reared separately. In contrast, when related males developed and emerged together before the experiment, female reproductive output was higher. Our results show that relatedness among males is insufficient to reduce harm to females, while a shared rearing environment - resulting in males similar to or familiar with one another - is necessary to generate this pattern.}, } @article {pmid25704962, year = {2016}, author = {Berman, CM}, title = {Primate Kinship: Contributions from Cayo Santiago.}, journal = {American journal of primatology}, volume = {78}, number = {1}, pages = {63-77}, doi = {10.1002/ajp.22383}, pmid = {25704962}, issn = {1098-2345}, support = {P40-OD-012217/OD/NIH HHS/United States ; P40-RR-01293/RR/NCRR NIH HHS/United States ; RR-01293/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Ethology/*history ; *Hierarchy, Social ; History, 20th Century ; History, 21st Century ; Macaca mulatta/*physiology ; Puerto Rico ; *Social Behavior ; }, abstract = {Research on Cayo Santiago and Japan deserves credit for launching the study of primate kinship and for continuing to help shape it in important ways. This review describes the origins of kinship research on Cayo Santiago, beginning with Donald Sade's pioneering work establishing the concepts of kin preferences, matrilineal dominance systems and incest avoidance. It then reviews subsequent research by later Cayo Santiago researchers and alumni, focusing primarily on maternal kinship. Together these researchers have greatly expanded our knowledge of kin preferences in rhesus in terms of (i) what age-sex classes, behaviors and types of kin show them, (ii) the ways in which kinship interfaces with rank, sex, age, and dispersal patterns, and (iii) the graded and variably limited nature of kin preferences in terms of degree of relatedness. Second, the argument for kin selection at least for some types of behavior has survived challenges posed by several alternative explanations, and has been both strengthened by recent findings of paternal kin preferences and narrowed by studies showing that unilateral altruism may extend only to very close kin. Third, work on Cayo Santiago has contributed to an appreciation that both current conditions and inherent social characteristics may influence the strength of kin preferences, and fourth, it has contributed to an understanding of the possible origins of our own species' family systems. Cayo Santiago became a leader in kinship research in large part because of management practices that produce known extended lineages. These lineages have promoted and accelerated research on kinship, prompting other researchers to investigate its importance in other groups and species, where its effects only then became clear. The extended lineages remain valuable tools for research on a species that lives in a broad range of environments in the wild, including those with key parallels to Cayo Santiago.}, } @article {pmid25698231, year = {2015}, author = {Koykka, C and Wild, G}, title = {The evolution of group dispersal with leaders and followers.}, journal = {Journal of theoretical biology}, volume = {371}, number = {}, pages = {117-126}, doi = {10.1016/j.jtbi.2015.02.008}, pmid = {25698231}, issn = {1095-8541}, mesh = {Altruism ; *Biological Evolution ; Humans ; *Leadership ; *Models, Theoretical ; Numerical Analysis, Computer-Assisted ; Social Behavior ; }, abstract = {In many species, individuals disperse in groups. While there are empirical studies that explore the proximate incentives for group dispersal, theoretical research has primarily examined the consequences rather than the evolution of this phenomenon. We design a simple model to study the origin and evolution of group dispersal. We assume that like many other group activities associated with collective movement, group dispersal in our model is initiated by leaders. We use the theory of inclusive fitness to examine the incentives for leading and following in this context. High relatedness, significant reductions in the cost of dispersal due to dispersing in groups, and reproductive skew in favour of followers facilitates the emergence of group dispersal. In contrast to some previous theoretical work, which has either concluded that leadership is uniformly altruistic or that it is uniformly selfish, we find that at evolutionary equilibrium the incentives for leading can be either selfish or altruistic. The nature of result (selfish or altruistic) depends on ecological and social conditions such as the cost of dispersal and the relatedness between leaders and followers. Our model demonstrates that kin selection is sufficient and that individual differences in condition and ability are not necessary to promote the emergence and maintenance of leader-follower relationships.}, } @article {pmid25694620, year = {2015}, author = {Kapheim, KM and Nonacs, P and Smith, AR and Wayne, RK and Wcislo, WT}, title = {Kinship, parental manipulation and evolutionary origins of eusociality.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1803}, pages = {20142886}, pmid = {25694620}, issn = {1471-2954}, mesh = {Altruism ; Animals ; Bees/genetics/*physiology ; Behavior, Animal ; Evolution, Molecular ; Female ; *Genetic Fitness ; Models, Biological ; Nesting Behavior ; Reproduction ; Social Behavior ; }, abstract = {One of the hallmarks of eusociality is that workers forego their own reproduction to assist their mother in raising siblings. This seemingly altruistic behaviour may benefit workers if gains in indirect fitness from rearing siblings outweigh the loss of direct fitness. If worker presence is advantageous to mothers, however, eusociality may evolve without net benefits to workers. Indirect fitness benefits are often cited as evidence for the importance of inclusive fitness in eusociality, but have rarely been measured in natural populations. We compared inclusive fitness of alternative social strategies in the tropical sweat bee, Megalopta genalis, for which eusociality is optional. Our results show that workers have significantly lower inclusive fitness than females that found their own nests. In mathematical simulations based on M. genalis field data, eusociality cannot evolve with reduced intra-nest relatedness. The simulated distribution of alternative social strategies matched observed distributions of M. genalis social strategies when helping behaviour was simulated as the result of maternal manipulation, but not as worker altruism. Thus, eusociality in M. genalis is best explained through kin selection, but the underlying mechanism is likely maternal manipulation.}, } @article {pmid25694043, year = {2015}, author = {Dugas, MB}, title = {Commentary: Parental care and the proximate links between maternal effects and offspring fitness.}, journal = {Oecologia}, volume = {177}, number = {4}, pages = {1089-1092}, pmid = {25694043}, issn = {1432-1939}, mesh = {Animals ; Egg Yolk/*chemistry ; Female ; Lutein/*chemistry ; Male ; Passeriformes/*physiology ; }, abstract = {Maternal effects influence the phenotype of offspring through non-genetic mechanisms, and thus are important components of individual life-histories and act as drivers of and/or constraints on phenotypic evolution. A maternal effect common in egg-laying vertebrates is provisioning of the yolk with carotenoids, organic pigments that often color sexual ornaments and are hypothesized to play positive and substantial physiological roles. In a recent study, yolks of great tit (Parus major) eggs were directly supplemented with carotenoids, and the effects on offspring fitness proxies measured (Marri and Richner in Oecologia 176:371-377, 2014a). Nestlings from supplemented broods were heavier early in development and more likely to fledge, but otherwise equivalent to control nestlings. The authors consider in detail the potential physiological mechanisms that might underlie this result, and here I expand on their Discussion by considering a non-exclusive explanation: that parents provided higher quality care to broods that received supplemental carotenoids. I discuss the general non-independence of pre- and post-hatching/parturition maternal effects when parents care for offspring, and then briefly review evidence that carotenoids specifically are tied to the intensity of avian begging displays. Finally, I detail how inclusive fitness opportunities and constraints shape the adaptive landscape in which maternal effects operate, highlighting both theoretical and applied concerns surrounding questions about the adaptiveness of maternal effects.}, } @article {pmid25688421, year = {2015}, author = {Bastiaans, E and Debets, AJ and Aanen, DK}, title = {Experimental demonstration of the benefits of somatic fusion and the consequences for allorecognition.}, journal = {Evolution; international journal of organic evolution}, volume = {69}, number = {4}, pages = {1091-1099}, doi = {10.1111/evo.12626}, pmid = {25688421}, issn = {1558-5646}, mesh = {Alleles ; *Biological Evolution ; Genetic Fitness ; *Genetic Variation ; Neurospora crassa/cytology/*genetics ; Spores, Fungal/cytology ; }, abstract = {Allorecognition, the ability to distinguish "self" from "nonself" based on allelic differences at allorecognition loci, is common in all domains of life. Allorecognition restricts the opportunities for social parasitism, and is therefore crucial for the evolution of cooperation. However, the maintenance of allorecognition diversity provides a paradox. If allorecognition is costly relative to cooperation, common alleles will be favored. Thus, the cost of allorecognition may reduce the genetic variation upon which allorecognition crucially relies, a prediction now known as "Crozier's paradox." We establish the relative costs of allorecognition, and their consequences for the short-term evolution of recognition labels theoretically predicted by Crozier. We use fusion among colonies of the fungus Neurospora crassa, regulated by highly variable allorecognition genes, as an experimental model system. We demonstrate that fusion among colonies is mutually beneficial, relative to absence of fusion upon allorecognition. This benefit is due not only to absence of mutual antagonism, which occurs upon allorecognition, but also to an increase in colony size per se. We then experimentally demonstrate that the benefit of fusion selects against allorecognition diversity, as predicted by Crozier. We discuss what maintains allorecognition diversity.}, } @article {pmid25673684, year = {2015}, author = {Hooper, PL and Gurven, M and Winking, J and Kaplan, HS}, title = {Inclusive fitness and differential productivity across the life course determine intergenerational transfers in a small-scale human society.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1803}, pages = {20142808}, pmid = {25673684}, issn = {1471-2954}, support = {2P01AG022500-06A1/AG/NIA NIH HHS/United States ; R01AG024119-01/AG/NIA NIH HHS/United States ; }, mesh = {Adolescent ; Adult ; Age Factors ; Aged ; Agriculture ; Biological Evolution ; Bolivia ; Child ; Child, Preschool ; Cooperative Behavior ; Efficiency ; *Family ; *Family Relations ; Feeding Behavior ; Female ; *Genetic Fitness ; Humans ; Indians, South American ; Infant ; Male ; Middle Aged ; Sex Factors ; *Social Behavior ; }, abstract = {Transfers of resources between generations are an essential element in current models of human life-history evolution accounting for prolonged development, extended lifespan and menopause. Integrating these models with Hamilton's theory of inclusive fitness, we predict that the interaction of biological kinship with the age-schedule of resource production should be a key driver of intergenerational transfers. In the empirical case of Tsimane' forager-horticulturalists in Bolivian Amazonia, we provide a detailed characterization of net transfers of food according to age, sex, kinship and the net need of donors and recipients. We show that parents, grandparents and siblings provide significant net downward transfers of food across generations. We demonstrate that the extent of provisioning responds facultatively to variation in the productivity and demographic composition of families, as predicted by the theory. We hypothesize that the motivation to provide these critical transfers is a fundamental force that binds together human nuclear and extended families. The ubiquity of three-generational families in human societies may thus be a direct reflection of fundamental evolutionary constraints on an organism's life-history and social organization.}, } @article {pmid25620834, year = {2015}, author = {Shackleton, K and Al Toufailia, H and Balfour, NJ and Nascimento, FS and Alves, DA and Ratnieks, FL}, title = {Appetite for self-destruction: suicidal biting as a nest defense strategy in Trigona stingless bees.}, journal = {Behavioral ecology and sociobiology}, volume = {69}, number = {2}, pages = {273-281}, pmid = {25620834}, issn = {0340-5443}, abstract = {Self-sacrificial behavior represents an extreme and relatively uncommon form of altruism in worker insects. It can occur, however, when inclusive fitness benefits are high, such as when defending the nest. We studied nest defense behaviors in stingless bees, which live in eusocial colonies subject to predation. We introduced a target flag to nest entrances to elicit defensive responses and quantified four measures of defensivity in 12 stingless bee species in São Paulo State, Brazil. These included three Trigona species, which are locally known for their aggression. Species varied significantly in their attack probability (cross species range = 0-1, P < 0.001), attack latency (7.0-23.5 s, P = 0.002), biting duration of individual bees (3.5-508.7 s, P < 0.001), and number of attackers (1.0-10.8, P < 0.001). A "suicide" bioassay on the six most aggressive species determined the proportion of workers willing to suffer fatal damage rather than disengage from an intruder. All six species had at least some suicidal individuals (7-83 %, P < 0.001), reaching 83 % in Trigona hyalinata. Biting pain was positively correlated with an index of overall aggression (P = 0.002). Microscopic examination revealed that all three Trigona species had five sharp teeth per mandible, a possible defensive adaptation and cause of increased pain. Suicidal defense via biting is a new example of self-sacrificial altruism and has both parallels and differences with other self-sacrificial worker insects, such as the honey bee. Our results indicate that suicidal biting may be a widespread defense strategy in stingless bees, but it is not universal.}, } @article {pmid25607654, year = {2015}, author = {Newman, SJ and Easteal, S}, title = {A new metric of inclusive fitness predicts the human mortality profile.}, journal = {PloS one}, volume = {10}, number = {1}, pages = {e0117019}, pmid = {25607654}, issn = {1932-6203}, mesh = {Child ; Evolution, Molecular ; *Genetic Fitness ; Genomics ; Human Migration ; Humans ; *Models, Genetic ; *Mortality ; Parents ; Selection, Genetic ; }, abstract = {Biological species have evolved characteristic patterns of age-specific mortality across their life spans. If these mortality profiles are shaped by natural selection they should reflect underlying variation in the fitness effect of mortality with age. Direct fitness models, however, do not accurately predict the mortality profiles of many species. For several species, including humans, mortality rates vary considerably before and after reproductive ages, during life-stages when no variation in direct fitness is possible. Variation in mortality rates at these ages may reflect indirect effects of natural selection acting through kin. To test this possibility we developed a new two-variable measure of inclusive fitness, which we term the extended genomic output or EGO. Using EGO, we estimate the inclusive fitness effect of mortality at different ages in a small hunter-gatherer population with a typical human mortality profile. EGO in this population predicts 90% of the variation in age-specific mortality. This result represents the first empirical measurement of inclusive fitness of a trait in any species. It shows that the pattern of human survival can largely be explained by variation in the inclusive fitness cost of mortality at different ages. More generally, our approach can be used to estimate the inclusive fitness of any trait or genotype from population data on birth dates and relatedness.}, } @article {pmid25594921, year = {2015}, author = {Swenson, SA}, title = {'From Man to Bacteria': W.D. Hamilton, the theory of inclusive fitness, and the post-war social order.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {49}, number = {}, pages = {45-54}, doi = {10.1016/j.shpsc.2014.12.001}, pmid = {25594921}, issn = {1879-2499}, mesh = {Bacteria/genetics ; *Biological Evolution ; *Genetic Fitness ; History, 20th Century ; Humans ; *Models, Genetic ; Plants/genetics ; *Selection, Genetic ; Social Conditions ; }, abstract = {W.D. Hamilton's theory of inclusive fitness aimed to define the evolved limits of altruism with mathematical precision. Although it was meant to apply universally, it has been almost irretrievably entwined with the particular case of social insects that featured in his famous 1964 papers. The assumption that social insects were central to Hamilton's early work contradicts material in his rich personal archive. In fact, careful study of Hamilton's notes, letters, diaries, and early essays indicates the extent to which he had humans in mind when he decided altruism was a topic worthy of biological inquiry. For this reason, this article reconsiders the role of extra-scientific factors in Hamilton's early theorizing. In doing so, it offers an alternative perspective as to why Hamilton saw self-sacrifice to be an important subject. Although the traditional narrative prioritizes his distaste for benefit-of-the-species explanations as a motivating factor behind his foundational work, I argue that greater attention ought to be given to Hamilton's hope that science could be used to address social ills. By reconsidering the meaning Hamilton intended inclusive fitness to have, we see that while he was no political ideologue, the socio-political relevance of his theory was nevertheless integral to its development.}, } @article {pmid25593513, year = {2015}, author = {Uggla, C and Mace, R}, title = {Someone to live for: effects of partner and dependent children on preventable death in a population wide sample from Northern Ireland.}, journal = {Evolution and human behavior : official journal of the Human Behavior and Evolution Society}, volume = {36}, number = {1}, pages = {1-7}, pmid = {25593513}, issn = {1090-5138}, support = {249347/ERC_/European Research Council/International ; }, abstract = {How to allocate resources between somatic maintenance and reproduction in a manner that maximizes inclusive fitness is a fundamental challenge for all organisms. Life history theory predicts that effort put into somatic maintenance (health) should vary with sex, mating and parenting status because men and women have different costs of reproduction, and because life transitions such as family formation alter the fitness payoffs from investing in current versus future reproduction. However, few tests of how such life history parameters influence behaviours closely linked to survival exist. Here we examine whether specific forms of preventable death (accidents/suicides, alcohol-related causes, and other preventable diseases) are predicted by marital status and dependent offspring in a modern developed context; that of Northern Ireland. We predict that men, non-partnered individuals and individuals who do not have dependent offspring will be at higher risk of preventable death. Running survival analyses on the entire adult population (aged 16-59, n = 927,134) controlling for socioeconomic position (SEP) and other potential confounds, we find that being single (compared to cohabiting/married) increases risk of accidental/suicide death for men (but not for women), whereas having dependent children is associated with lower risk of preventable mortality for women but less so for men. We also find that the protective effect of partners is larger for men with low SEP than for high SEP men. Findings support life history predictions and suggest that individuals respond to variation in fitness costs linked to their mating and parenting status.}, } @article {pmid25589605, year = {2015}, author = {Lehtonen, J and Kokko, H}, title = {Why inclusive fitness can make it adaptive to produce less fit extra-pair offspring.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1801}, pages = {20142716}, pmid = {25589605}, issn = {1471-2954}, mesh = {Animals ; Birds/genetics/*physiology ; Female ; *Genetic Fitness ; Male ; Models, Biological ; *Reproduction ; *Sexual Behavior, Animal ; }, abstract = {Social monogamy predominates in avian breeding systems, but most socially monogamous species engage in promiscuous extra-pair copulations (EPCs). The reasons behind this remain debated, and recent empirical work has uncovered patterns that do not seem to fit existing hypotheses. In particular, some results seem to contradict the inbreeding avoidance hypothesis: females can prefer extra-pair partners that are more closely related to them than their social partners, and extra-pair young can have lower fitness than within-pair young. Motivated by these studies, we show that such results can become explicable when an asymmetry in inbreeding tolerance between monogamy and polygamy is extended to species that combine both strategies within a single reproductive season. Under fairly general conditions, it can be adaptive for a female to choose an unrelated social partner, but inbreed with an extra-pair partner. Inbreeding depression is compensated for by inclusive fitness benefits, which are only fully realized in EPCs. We also show that if a female has already formed a suboptimal social bond, there are scenarios where it is beneficial to engage in EPCs with less related males, and others where EPCs with more related males increase her inclusive fitness. This has implications for detecting general relatedness or fitness trends when averaged over several species.}, } @article {pmid25545864, year = {2015}, author = {Helanterä, H and d'Ettorre, P}, title = {A comparative study of egg recognition signature mixtures in Formica ants.}, journal = {Evolution; international journal of organic evolution}, volume = {69}, number = {2}, pages = {520-529}, doi = {10.1111/evo.12590}, pmid = {25545864}, issn = {1558-5646}, mesh = {Animals ; Ants/chemistry/*genetics/physiology ; Behavior, Animal ; Cues ; Finland ; Hydrocarbons/*chemistry ; Odorants ; Ovum/*chemistry ; *Social Behavior ; Species Specificity ; }, abstract = {Processing of information from the environment, such as assessing group membership in social contexts, is a major determinant of inclusive fitness. For social insects, recognizing brood origin is crucial for inclusive fitness in many contexts, such as social parasitism and kin conflicts within colonies. Whether a recognition signature is informative in kin conflicts depends on the extent of a genetic contribution into the cues. We investigated colony- and matriline-specific variation in egg surface hydrocarbons in seven species of Formica ants. We show that chemical variance is distributed similarly to genetic variation, suggesting a significant genetic contribution to eggs odors in the genus. Significant among matriline components, and significant correlations between chemical and genetic similarity among individuals also indicate kin informative egg odors in several species. We suggest that egg odor surface variation could play a large role in within colony conflicts, and that a comparative method can reveal novel insight into communication of identity.}, } @article {pmid25512842, year = {2014}, author = {Simonsen, AK and Chow, T and Stinchcombe, JR}, title = {Reduced plant competition among kin can be explained by Jensen's inequality.}, journal = {Ecology and evolution}, volume = {4}, number = {23}, pages = {4454-4466}, pmid = {25512842}, issn = {2045-7758}, abstract = {Plants often compete with closely related individuals due to limited dispersal, leading to two commonly invoked predictions on competitive outcomes. Kin selection, from evolutionary theory, predicts that competition between relatives will likely be weaker. The niche partitioning hypothesis, from ecological theory, predicts that competition between close relatives will likely be stronger. We tested for evidence consistent with either of these predictions by growing an annual legume in kin and nonkin groups in the greenhouse. We grew plant groups in treatments of symbiotic nitrogen fixing bacteria differing in strain identity and composition to determine if differences in the microbial environment can facilitate or obscure plant competition patterns consistent with kin selection or niche partitioning. Nonkin groups had lower fitness than expected, based on fitness estimates of the same genotypes grown among kin. Higher fitness among kin groups was observed in mixtures of N-fixing bacteria strains compared to single inoculations of bacteria strains present in the soil, which increased fitness differences between kin and nonkin groups. Lower fitness in nonkin groups was likely caused by increased competitive asymmetry in nonkin groups due to genetic differences in plant size combined with saturating relationships with plant size and fitness- i.e. Jensen's inequality. Our study suggests that microbial soil symbionts alter competitive dynamics among kin and nonkin. Our study also suggests that kin groups can have higher fitness, as predicted by kin selection theory, through a commonly heritable trait (plant size), without requiring kin recognition mechanisms.}, } @article {pmid25505483, year = {2014}, author = {Muir, WM and Cheng, HW and Croney, C}, title = {Methods to address poultry robustness and welfare issues through breeding and associated ethical considerations.}, journal = {Frontiers in genetics}, volume = {5}, number = {}, pages = {407}, pmid = {25505483}, issn = {1664-8021}, abstract = {As consumers and society in general become more aware of ethical and moral dilemmas associated with intensive rearing systems, pressure is put on the animal and poultry industries to adopt alternative forms of housing. This presents challenges especially regarding managing competitive social interactions between animals. However, selective breeding programs are rapidly advancing, enhanced by both genomics and new quantitative genetic theory that offer potential solutions by improving adaptation of the bird to existing and proposed production environments. The outcomes of adaptation could lead to improvement of animal welfare by increasing fitness of the animal for the given environments, which might lead to increased contentment and decreased distress of birds in those systems. Genomic selection, based on dense genetic markers, will allow for more rapid improvement of traits that are expensive or difficult to measure, or have a low heritability, such as pecking, cannibalism, robustness, mortality, leg score, bone strength, disease resistance, and thus has the potential to address many poultry welfare concerns. Recently selection programs to include social effects, known as associative or indirect genetic effects (IGEs), have received much attention. Group, kin, multi-level, and multi-trait selection including IGEs have all been shown to be highly effective in reducing mortality while increasing productivity of poultry layers and reduce or eliminate the need for beak trimming. Multi-level selection was shown to increases robustness as indicated by the greater ability of birds to cope with stressors. Kin selection has been shown to be easy to implement and improve both productivity and animal well-being. Management practices and rearing conditions employed for domestic animal production will continue to change based on ethical and scientific results. However, the animal breeding tools necessary to provide an animal that is best adapted to these changing conditions are readily available and should be used, which will ultimately lead to the best possible outcomes for all impacted.}, } @article {pmid25451769, year = {2015}, author = {Houchmandzadeh, B}, title = {Fluctuation driven fixation of cooperative behavior.}, journal = {Bio Systems}, volume = {127}, number = {}, pages = {60-66}, doi = {10.1016/j.biosystems.2014.11.006}, pmid = {25451769}, issn = {1872-8324}, mesh = {*Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Genetic Drift ; Genetics, Population ; Humans ; *Models, Biological ; Population Density ; *Selection, Genetic ; }, abstract = {Cooperative behaviors are defined as the production of common goods benefitting all members of the community at the producer's cost. They could seem to be in contradiction with natural selection, as non-cooperators have an increased fitness compared to cooperators. Understanding the emergence of cooperation has necessitated the development of concepts and models (inclusive fitness, multilevel selection, etc.) attributing deterministic advantages to this behavior. In contrast to these models, we show here that cooperative behaviors can emerge by taking into account only the stochastic nature of evolutionary dynamics: when cooperative behaviors increase the population size, they also increase the genetic drift against non-cooperators. Using the Wright-Fisher models of population genetics, we compute exactly this increased genetic drift and its consequences on the fixation probability of both types of individuals. This computation leads to a simple criterion: cooperative behavior dominates when the relative increase in population size caused by cooperators is higher than the selection pressure against them. This is a purely stochastic effect with no deterministic interpretation.}, } @article {pmid25438185, year = {2014}, author = {Schultner, E and Gardner, A and Karhunen, M and Helanterä, H}, title = {Ant larvae as players in social conflict: relatedness and individual identity mediate cannibalism intensity.}, journal = {The American naturalist}, volume = {184}, number = {6}, pages = {E161-74}, doi = {10.1086/678459}, pmid = {25438185}, issn = {1537-5323}, mesh = {Animals ; Ants/genetics/*physiology ; Behavior, Animal ; *Cannibalism ; Female ; Larva/physiology ; Male ; Sex Characteristics ; Social Behavior ; }, abstract = {Conflict arises among social organisms when individuals differ in their inclusive-fitness interests. Ant societies are excellent models for understanding how genetic relatedness mediates conflict intensity. However, although conflicts within colonies typically arise over offspring production, the role of larvae as actors in social conflict has received little attention. We develop and empirically test kin-selection theory of larval egg cannibalism in ant societies. Specifically, we investigate how selection for cannibalism is mediated by nestmate relatedness and larval sex in a mathematical model and then test the model's predictions by measuring cannibalism levels in eight ant species with varying nestmate relatedness. In line with our theoretical predictions, cannibalism levels in larvae were significantly influenced by relatedness and sex. Increased relatedness was associated with reduced levels of cannibalism, indicating that larval behavior is mediated by inclusive-fitness considerations. Levels of cannibalism were significantly higher in male larvae, and our model suggests that this is due to sex differences in the benefits of cannibalism. By examining the selfish interests of larvae and the constraints they face in a social environment, our study presents a novel perspective on conflict in ants and on the evolution of selfish elements in social systems in general.}, } @article {pmid25416727, year = {2014}, author = {Gagliano, M}, title = {In a green frame of mind: perspectives on the behavioural ecology and cognitive nature of plants.}, journal = {AoB PLANTS}, volume = {7}, number = {}, pages = {}, pmid = {25416727}, issn = {2041-2851}, abstract = {It is increasingly recognized that plants are highly sensitive organisms that perceive, assess, learn, remember, resolve problems, make decisions and communicate with each other by actively acquiring information from their environment. However, the fact that many of the sophisticated behaviours plants exhibit reveal cognitive competences, which are generally attributed to humans and some non-human animals, has remained unappreciated. Here, I will outline the theoretical barriers that have precluded the opportunity to experimentally test such behavioural/cognitive phenomena in plants. I will then suggest concrete alternative approaches to cognition by highlighting how (i) the environment offers a multitude of opportunities for decision-making and action and makes behaviours possible, rather than causing them; (ii) perception in itself is action in the form of a continuous flow of information; (iii) all living organisms viewed within this context become agents endowed with autonomy rather than objects in a mechanistically conceived world. These viewpoints, combined with recent evidence, may contribute to move the entire field towards an integrated study of cognitive biology.}, } @article {pmid25400313, year = {2014}, author = {Espinosa, A and Paz-Y-Miño-C, G}, title = {Evidence of Taxa-, Clone-, and Kin-discrimination in Protists: Ecological and Evolutionary Implications.}, journal = {Evolutionary ecology}, volume = {28}, number = {6}, pages = {1019-1029}, pmid = {25400313}, issn = {0269-7653}, support = {P20 GM103430/GM/NIGMS NIH HHS/United States ; }, abstract = {Unicellular eukaryotes, or protists, are among the most ancient organisms on Earth. Protists belong to multiple taxonomic groups; they are widely distributed geographically and in all environments. Their ability to discriminate among con- and heterospecifics has been documented during the past decade. Here we discuss exemplar cases of taxa-, clone-, and possible kin-discrimination in five major lineages: Mycetozoa (Dictyostelium, Polysphondylium), Dikarya (Saccharomyces), Ciliophora (Tetrahymena), Apicomplexa (Plasmodium) and Archamoebae (Entamoeba). We summarize the proposed genetic mechanisms involved in discrimination-mediated aggregation (self versus different), including the csA, FLO and trg (formerly lag) genes, and the Proliferation Activation Factors (PAFs), which facilitate clustering in some protistan taxa. We caution about the experimental challenges intrinsic to studying recognition in protists, and highlight the opportunities for exploring the ecology and evolution of complex forms of cell-cell communication, including social behavior, in a polyphyletic, still superficially understood group of organisms. Because unicellular eukaryotes are the evolutionary precursors of multicellular life, we infer that their mechanisms of taxa-, clone-, and possible kin-discrimination gave origin to the complex diversification and sophistication of traits associated with species and kin recognition in plants, fungi, invertebrates and vertebrates.}, } @article {pmid25399677, year = {2015}, author = {Bădescu, I and Sicotte, P and Ting, N and Wikberg, EC}, title = {Female parity, maternal kinship, infant age and sex influence natal attraction and infant handling in a wild colobine (Colobus vellerosus).}, journal = {American journal of primatology}, volume = {77}, number = {4}, pages = {376-387}, doi = {10.1002/ajp.22353}, pmid = {25399677}, issn = {1098-2345}, mesh = {Age Factors ; Animals ; Behavior, Animal/*physiology ; Colobus/*physiology ; Female ; Genotype ; Ghana ; Grooming ; Male ; Maternal Behavior ; Microsatellite Repeats ; Parity ; Pedigree ; Sex Factors ; *Social Behavior ; Social Dominance ; }, abstract = {Primate females often inspect, touch and groom others' infants (natal attraction) and they may hold and carry these infants in a manner resembling maternal care (infant handling). While natal attraction and infant handling occur in most wild colobines, little is known about the factors influencing the expression of these behaviors. We examined the effects of female parity, kinship, and dominance rank, as well as infant age and sex in wild Colobus vellerosus at Boabeng-Fiema Monkey Sanctuary, Ghana. We collected data via focal sampling of females in 2008 and 2009 (N = 61) and of infants in 2010 (N = 12). Accounting for the individuals who interacted with our focal subjects, this study includes 74 females and 66 infants in 8 groups. We recorded female agonistic interactions ad libitum to determine dominance ranks. We used partial pedigree information and genotypes at 17 short tandem repeat loci to determine kinship. We knew female parity, infant age and sex from demographic records. Nulliparous females showed more natal attraction and infant handling than parous females, which may suggest that interactions with infants are more adaptive for nulliparous females because they learn mothering skills through these behaviors. Compared to non-kin, maternal kin were more likely to handle infants. Maternal kin may be permitted greater access to infants because mothers are most familiar with them. Handlers may incur inclusive fitness benefits from infant handling. Dominance rank did not affect female interactions with infants. The youngest infants received the most natal attraction and infant handling, and male infants were handled more than female infants. The potential benefits of learning to mother and inclusive fitness, in combination with the relatively low costs of natal attraction and infant handling, may explain the high rates of these behaviors in many colobines.}, } @article {pmid25389411, year = {2014}, author = {Fukui, H and Toyoshima, K}, title = {Chill-inducing music enhances altruism in humans.}, journal = {Frontiers in psychology}, volume = {5}, number = {}, pages = {1215}, pmid = {25389411}, issn = {1664-1078}, abstract = {Music is a universal feature of human cultures, and it has both fascinated and troubled many researchers. In this paper we show through the dictator game (DG) that an individual's listening to preferred "chill-inducing" music may promote altruistic behavior that extends beyond the bounds of kin selection or reciprocal altruism. Participants were 22 undergraduate and postgraduate students who were divided into two groups, the in-group and the out-group, and they acted as dictators. The dictators listened to their own preferred "chill-inducing" music, to music they disliked, or to silence, and then played the DG. In this hypothetical experiment, the dictators were given real money (which they did not keep) and were asked to distribute it to the recipients, who were presented as stylized images of men and women displayed on a computer screen. The dictators played the DG both before and after listening to the music. Both male and female dictators gave more money after listening to their preferred music and less after listening to the music they disliked, whereas silence had no effect on the allocated amounts. The group to which the recipient belonged did not influence these trends. The results suggest that listening to preferred "chill-inducing" music promotes altruistic behavior.}, } @article {pmid25389109, year = {2015}, author = {Pizzari, T and Biernaskie, JM and Carazo, P}, title = {Inclusive fitness and sexual conflict: how population structure can modulate the battle of the sexes.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {37}, number = {2}, pages = {155-166}, doi = {10.1002/bies.201400130}, pmid = {25389109}, issn = {1521-1878}, support = {BB/L009587/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Female ; Male ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; }, abstract = {Competition over reproductive opportunities among members of one sex often harms the opposite sex, creating a conflict of interest between individual males and females. Recently, this battle of the sexes has become a paradigm in the study of intersexual coevolution. Here, we review recent theoretical and empirical advances suggesting that - as in any scenario of intraspecific competition - selfishness (competitiveness) can be influenced by the genetic relatedness of competitors. When competitors are positively related (e.g. siblings), an individual may refrain from harming its competitor(s) and their mate(s) because this can improve the focal individual's inclusive fitness. These findings reveal that population genetic structure might be of paramount importance when studying the battle of the sexes. We conclude by identifying some new lines of research at the interface of sexual selection and social evolution.}, } @article {pmid25362869, year = {2014}, author = {Snyder-Mackler, N and Alberts, SC and Bergman, TJ}, title = {The socio-genetics of a complex society: female gelada relatedness patterns mirror association patterns in a multilevel society.}, journal = {Molecular ecology}, volume = {23}, number = {24}, pages = {6179-6191}, doi = {10.1111/mec.12987}, pmid = {25362869}, issn = {1365-294X}, mesh = {Animals ; *Behavior, Animal ; DNA, Mitochondrial/genetics ; Female ; Genetic Fitness ; Genotype ; Male ; *Social Behavior ; Theropithecus/*genetics/*physiology ; }, abstract = {Multilevel societies with fission-fusion dynamics--arguably the most complex animal societies--are defined by two or more nested levels of organization. The core of these societies are modular social units that regularly fission and fuse with one another. Despite convergent evolution in disparate taxa, we know strikingly little about how such societies form and how fitness benefits operate. Understanding the kinship structure of complex societies could inform us about the origins of the social structure as well as about the potential for individuals in these societies to accrue indirect fitness benefits. Here, we combined genetic and behavioural data on geladas (Theropithecus gelada), an Old World Monkey, to complete the most comprehensive socio-genetic analysis of a multilevel society to date. In geladas, individuals in the core social 'units', associate at different frequencies to form 'teams', 'bands' and, the largest aggregations, 'communities'. Units were composed of closely related females, and females remained with their close kin during permanent fissions of units. Interestingly, female-female relatedness also significantly predicted between-unit, between-team and between-band association patterns, while male-male relatedness did not. Thus, it is likely that the socio-genetic structure of gelada society results from females maintaining associations with their female relatives during successive unit fissions--possibly in an attempt to balance the direct and indirect fitness benefits of group living. Overall, the persistence of associations among related females across generations appears to drive the formation of higher levels of gelada society, suggesting that females seek kin for inclusive fitness benefits at multiple levels of gelada society.}, } @article {pmid25347943, year = {2016}, author = {Richerson, P and Baldini, R and Bell, AV and Demps, K and Frost, K and Hillis, V and Mathew, S and Newton, EK and Naar, N and Newson, L and Ross, C and Smaldino, PE and Waring, TM and Zefferman, M}, title = {Cultural group selection plays an essential role in explaining human cooperation: A sketch of the evidence.}, journal = {The Behavioral and brain sciences}, volume = {39}, number = {}, pages = {e30}, doi = {10.1017/S0140525X1400106X}, pmid = {25347943}, issn = {1469-1825}, mesh = {Adaptation, Physiological ; Altruism ; Biological Evolution ; Competitive Behavior ; *Cooperative Behavior ; *Cultural Evolution ; Group Processes ; Humans ; Interpersonal Relations ; Selection, Genetic ; Social Behavior ; }, abstract = {Human cooperation is highly unusual. We live in large groups composed mostly of non-relatives. Evolutionists have proposed a number of explanations for this pattern, including cultural group selection and extensions of more general processes such as reciprocity, kin selection, and multi-level selection acting on genes. Evolutionary processes are consilient; they affect several different empirical domains, such as patterns of behavior and the proximal drivers of that behavior. In this target article, we sketch the evidence from five domains that bear on the explanatory adequacy of cultural group selection and competing hypotheses to explain human cooperation. Does cultural transmission constitute an inheritance system that can evolve in a Darwinian fashion? Are the norms that underpin institutions among the cultural traits so transmitted? Do we observe sufficient variation at the level of groups of considerable size for group selection to be a plausible process? Do human groups compete, and do success and failure in competition depend upon cultural variation? Do we observe adaptations for cooperation in humans that most plausibly arose by cultural group selection? If the answer to one of these questions is "no," then we must look to other hypotheses. We present evidence, including quantitative evidence, that the answer to all of the questions is "yes" and argue that we must take the cultural group selection hypothesis seriously. If culturally transmitted systems of rules (institutions) that limit individual deviance organize cooperation in human societies, then it is not clear that any extant alternative to cultural group selection can be a complete explanation.}, } @article {pmid25305337, year = {2014}, author = {Czárán, T and Hoekstra, RF and Aanen, DK}, title = {Selection against somatic parasitism can maintain allorecognition in fungi.}, journal = {Fungal genetics and biology : FG & B}, volume = {73}, number = {}, pages = {128-137}, doi = {10.1016/j.fgb.2014.09.010}, pmid = {25305337}, issn = {1096-0937}, mesh = {Animals ; Ascomycota ; *Biological Evolution ; Models, Biological ; Parasites/*genetics/metabolism ; Symbiosis/*genetics ; }, abstract = {Fusion between multicellular individuals is possible in many organisms with modular, indeterminate growth, such as marine invertebrates and fungi. Although fusion may provide various benefits, fusion usually is restricted to close relatives by allorecognition, also called heterokaryon or somatic incompatibility in fungi. A possible selective explanation for allorecognition is protection against somatic parasites. Such mutants contribute less to colony functions but more to reproduction. However, previous models testing this idea have failed to explain the high diversity of allorecognition alleles in nature. These models did not, however, consider the possible role of spatial structure. We model the joint evolution of allorecognition and somatic parasitism in a multicellular organism resembling an asexual ascomycete fungus in a spatially explicit simulation. In a 1000-by-1000 grid, neighbouring individuals can fuse, but only if they have the same allotype. Fusion with a parasitic individual decreases the total reproductive output of the fused individuals, but the parasite compensates for this individual-level fitness reduction by a disproportional share of the offspring. Allorecognition prevents the invasion of somatic parasites, and vice versa, mutation towards somatic parasitism provides the selective conditions for extensive allorecognition diversity. On the one hand, if allorecognition diversity did not build up fast enough, somatic parasites went to fixation; conversely, once parasites had gone to fixation no allorecognition diversity built up. On the other hand, the mere threat of parasitism could select for high allorecognition diversity, preventing invasion of somatic parasites. Moderate population viscosity combined with weak global dispersal was optimal for the joint evolution of allorecognition and protection against parasitism. Our results are consistent with the widespread occurrence of allorecognition in fungi and the low degree of somatic parasitism. We discuss the implications of our results for allorecognition in other organism groups.}, } @article {pmid25300048, year = {2014}, author = {Kostic, B and Yadon, CA}, title = {Infidelity and kin selection: does cheating seem as bad when it's "all in the family"?.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {12}, number = {4}, pages = {687-705}, pmid = {25300048}, issn = {1474-7049}, mesh = {Adolescent ; Adult ; *Deception ; Family/*psychology ; Female ; Humans ; Male ; Sexual Behavior/*psychology ; Sexual Partners/*psychology ; Young Adult ; }, abstract = {The current study explored people's perceptions of how they would feel if their partners cheated on them by having sex with their relatives, such as if a man's wife had sex with his brother. Kin selection theory suggests that in such situations, victims of infidelity might feel slightly better if their partners had sex with biological relatives (compared to sex with nonrelatives) because some of the victims' genes could still get passed on through their relatives. In two experiments, participants reported how they would feel in various scenarios involving their partners having sex with participants' relatives and nonrelatives. As expected, participants generally reported being very disapproving of a partner's hypothetical infidelity with both their relatives and nonrelatives. However, contrary to predictions generated by kin selection theory, participants tended to report that they would feel worse if their partners had sex with their relatives. We propose several explanations for the current findings and discuss their implications for kin selection theory.}, } @article {pmid25297948, year = {2015}, author = {Engelmoer, DJP and Kiers, ET}, title = {Host diversity affects the abundance of the extraradical arbuscular mycorrhizal network.}, journal = {The New phytologist}, volume = {205}, number = {4}, pages = {1485-1491}, doi = {10.1111/nph.13086}, pmid = {25297948}, issn = {1469-8137}, mesh = {*Biodiversity ; Mycorrhizae/growth & development/*physiology ; Plants/*microbiology ; Species Specificity ; Symbiosis/*physiology ; }, abstract = {Arbuscular mycorrhizal fungi (AMF) can form complex networks in the soil that connect different host plants. Previous studies have focused on the effects of these networks on individual hosts and host communities. However, very little is known about how different host species affect the success of the fungal network itself. Given the potentially strong selection pressure against hosts that invest in a fungal network which benefits their competitors, we predict that the presence of multiple host species negatively affects the growth of the extraradical network. We designed an experiment using an in vitro culture approach to investigate the effect of different hosts (carrot, chichory and medicago) on the formation of a common mycelial network. In vitro root cultures, each inoculated with their own fungal network, were grown in a double split plate design with two host compartments and a common central compartment where fungal networks could form. We found that the size of fungal networks differs depending on the social environment of the host. When host species were propagated in a mixed species environment, the fungal abundance was significantly reduced compared to monoculture predictions. Our work demonstrates how host-to-host conflict can influence the abundance of the fungal partner.}, } @article {pmid25277060, year = {2014}, author = {Hames, R}, title = {Diversity in human behavioral ecology.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {25}, number = {4}, pages = {443-447}, pmid = {25277060}, issn = {1936-4776}, mesh = {*Aggression ; *Biological Evolution ; Cooperative Behavior ; Cultural Evolution ; Humans ; *Social Behavior ; *Warfare ; }, abstract = {As befitting an evolutionary approach to the study of human behavior, the papers in this special issue of Human Nature cover a diversity of topics in modern and traditional societies. They include the goals of hunting in foraging societies, social bias, cooperative breeding, the impact of war on women, leadership, and social mobility. In combination these contributions demonstrate the utility of selectionist's thinking on a wide variety of topics. While many of the contributions employ standard evolutionary biological approaches such as kin selection, cooperative breeding and the Trivers-Willard model, others examine important human issues such as the problems of trust, the cost of war to women, the characteristics of leaders, and what might be called honest or rule-bound fights. One striking feature of many of the contributions is a novel reexamination of traditional research questions from an evolutionary perspective.}, } @article {pmid25263625, year = {2014}, author = {Lebigre, C and Alatalo, RV and Soulsbury, CD and Höglund, J and Siitari, H}, title = {Limited indirect fitness benefits of male group membership in a lekking species.}, journal = {Molecular ecology}, volume = {23}, number = {21}, pages = {5356-5365}, doi = {10.1111/mec.12941}, pmid = {25263625}, issn = {1365-294X}, mesh = {Animals ; Female ; Finland ; Galliformes/*genetics ; *Genetic Fitness ; Genotype ; Male ; Microsatellite Repeats ; Models, Statistical ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {In group living species, individuals may gain the indirect fitness benefits characterizing kin selection when groups contain close relatives. However, tests of kin selection have primarily focused on cooperatively breeding and eusocial species, whereas its importance in other forms of group living remains to be fully understood. Lekking is a form of grouping where males display on small aggregated territories, which females then visit to mate. As females prefer larger aggregations, territorial males might gain indirect fitness benefits if their presence increases the fitness of close relatives. Previous studies have tested specific predictions of kin selection models using measures such as group-level relatedness. However, a full understanding of the contribution of kin selection in the evolution of group living requires estimating individuals' indirect fitness benefits across multiple sites and years. Using behavioural and genetic data from the black grouse (Tetrao tetrix), we show that the indirect fitness benefits of group membership were very small because newcomers joined leks containing few close relatives who had limited mating success. Males' indirect fitness benefits were higher in yearlings during increasing population density but marginally changed the variation in male mating success. Kin selection acting through increasing group size is therefore unlikely to contribute substantially to the evolution and maintenance of lekking in this black grouse population.}, } @article {pmid25262856, year = {2014}, author = {Pamminger, T and Foitzik, S and Metzler, D and Pennings, PS}, title = {Oh sister, where art thou? Spatial population structure and the evolution of an altruistic defence trait.}, journal = {Journal of evolutionary biology}, volume = {27}, number = {11}, pages = {2443-2456}, doi = {10.1111/jeb.12496}, pmid = {25262856}, issn = {1420-9101}, mesh = {Altruism ; Animals ; *Biological Evolution ; Female ; Host-Parasite Interactions/genetics/*physiology ; Hymenoptera/genetics/*parasitology/*physiology ; Male ; Models, Biological ; Population Dynamics ; Social Behavior ; }, abstract = {The evolution of parasite virulence and host defences is affected by population structure. This effect has been confirmed in studies focusing on large spatial scales, whereas the importance of local structure is not well understood. Slavemaking ants are social parasites that exploit workers of another species to rear their offspring. Enslaved workers of the host species Temnothorax longispinosus have been found to exhibit an effective post-enslavement defence behaviour: enslaved workers were observed killing a large proportion of the parasites' offspring. As enslaved workers do not reproduce, they gain no direct fitness benefit from this 'rebellion' behaviour. However, there may be an indirect benefit: neighbouring host nests that are related to 'rebel' nests can benefit from a reduced raiding pressure, as a result of the reduction in parasite nest size due to the enslaved workers' killing behaviour. We use a simple mathematical model to examine whether the small-scale population structure of the host species could explain the evolution of this potentially altruistic defence trait against slavemaking ants. We find that this is the case if enslaved host workers are related to nearby host nests. In a population genetic study, we confirm that enslaved workers are, indeed, more closely related to host nests within the raiding range of their resident slavemaker nest, than to host nests outside the raiding range. This small-scale population structure seems to be a result of polydomy (e.g. the occupation of several nests in close proximity by a single colony) and could have enabled the evolution of 'rebellion' by kin selection.}, } @article {pmid25253459, year = {2014}, author = {Dubuc, C and Winters, S and Allen, WL and Brent, LJ and Cascio, J and Maestripieri, D and Ruiz-Lambides, AV and Widdig, A and Higham, JP}, title = {Sexually selected skin colour is heritable and related to fecundity in a non-human primate.}, journal = {Proceedings. Biological sciences}, volume = {281}, number = {1794}, pages = {20141602}, pmid = {25253459}, issn = {1471-2954}, support = {P40 RR003640/RR/NCRR NIH HHS/United States ; 2P40RR03640-25/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Female ; Fertility/*genetics ; Macaca mulatta/*genetics/*psychology ; Male ; *Mating Preference, Animal ; Phenotype ; Pigmentation/*genetics ; *Sex Characteristics ; }, abstract = {Sexual selection promotes the prevalence of heritable traits that increase an individual's reproductive rate. Despite theoretically strong directional selection, sexually selected traits can show inter-individual variation. Here, we investigate whether red skin ornamentation, a rare example of a male mammalian trait involved in mate attraction, influences fecundity and is heritable in rhesus macaques (Macaca mulatta), and explore the mechanisms that are involved in maintaining trait variation. Interestingly, the trait is expressed by and is attractive to both sexes. We collected facial images of 266 free-ranging individuals and modelled skin redness and darkness to rhesus macaque vision. We used 20 years of genetic parentage data to calculate selection gradients on the trait and perform heritability analyses. Results show that males who were both darkly coloured and high-ranking enjoyed higher fecundity. Female skin redness was positively linked to fecundity, although it remains unclear whether this influences male selectiveness. Heritability explained 10-15% of the variation in redness and darkness, and up to 30% for skin darkness when sexes are considered separately, suggesting sex-influenced inheritance. Our results suggest that inter-individual variation is maintained through condition-dependence, with an added effect of balancing selection on male skin darkness, providing rare evidence for a mammalian trait selected through inter-sexual selection.}, } @article {pmid25231372, year = {2014}, author = {van Dongen, WF and Wagner, RH and Moodley, Y and Schaedelin, FC}, title = {Sex biases in kin shoaling and dispersal in a cichlid fish.}, journal = {Oecologia}, volume = {176}, number = {4}, pages = {965-974}, pmid = {25231372}, issn = {1432-1939}, mesh = {Animals ; *Cichlids/genetics ; Female ; *Genotype ; Male ; Microsatellite Repeats ; *Phenotype ; Population Dynamics ; Predatory Behavior ; *Sex Characteristics ; *Social Behavior ; }, abstract = {Animal dispersal is associated with diverse costs and benefits that vary among individuals based on phenotype and ecological conditions. For example, females may disperse when males benefit more from defending territories in familiar environments. Similarly, size differences in dispersal propensity may occur when dispersal costs are size-dependent. When individuals do disperse, they may adopt behavioral strategies that minimize dispersal costs. Dispersing fish, for example, may travel within shoals to reduce predation risks. Further, kin shoaling may augment inclusive fitness by reducing predation of relatives. However, studies are lacking on the role of kin shoaling in dispersal. We explored how sex and size influence dispersal and kin shoaling in the cichlid Neolamprologus caudopunctatus. We microsatellite genotyped over 900 individuals from two populations separated by a potential dispersal barrier, and documented patterns of population structure, migration and within-shoal relatedness. Genetic differentiation across the barrier was greater for smaller than larger fish, suggesting larger fish had dispersed longer distances. Females exhibited weaker genetic differentiation and 11 times higher migration rates than males, indicating longer-distance female-biased dispersal. Small females frequently shoaled with siblings, possibly offsetting dispersal costs associated with higher predation risks. In contrast, small males appeared to avoid kin shoaling, possibly to avoid local resource competition. In summary, long-distance dispersal in N. caudopunctatus appears to be female-biased, and kin-based shoaling by small females may represent a behavioral adaptation that reduces dispersal costs. Our study appears to be the first to provide evidence that sex differences in dispersal influence sex differences in kin shoaling.}, } @article {pmid25226188, year = {2014}, author = {Birch, J and Marshall, JA}, title = {Queller's separation condition explained and defended.}, journal = {The American naturalist}, volume = {184}, number = {4}, pages = {531-540}, doi = {10.1086/677750}, pmid = {25226188}, issn = {1537-5323}, mesh = {Animals ; *Biological Evolution ; Game Theory ; Models, Genetic ; Phenotype ; Selection, Genetic ; *Social Behavior ; }, abstract = {The theories of inclusive fitness and multilevel selection provide alternative perspectives on social evolution. The question of whether these perspectives are of equal generality remains a divisive issue. In an analysis based on the Price equation, Queller argued (by means of a principle he called the separation condition) that the two approaches are subject to the same limitations, arising from their fundamentally quantitative-genetical character. Recently, van Veelen et al. have challenged Queller's results, using this as the basis for a broader critique of the Price equation, the separation condition, and the very notion of inclusive fitness. Here we show that the van Veelen et al. model, when analyzed in the way Queller intended, confirms rather than refutes his original conclusions. We thereby confirm (i) that Queller's separation condition remains a legitimate theoretical principle and (ii) that the standard inclusive fitness and multilevel approaches are indeed subject to the same limitations.}, } @article {pmid25226183, year = {2014}, author = {Tarnita, CE and Taylor, PD}, title = {Measures of relative fitness of social behaviors in finite structured population models.}, journal = {The American naturalist}, volume = {184}, number = {4}, pages = {477-488}, doi = {10.1086/677924}, pmid = {25226183}, issn = {1537-5323}, mesh = {Animals ; Biological Evolution ; Game Theory ; Gene Frequency ; *Genetic Fitness ; Genetics, Population ; *Models, Genetic ; Probability ; *Social Behavior ; }, abstract = {How should we measure the relative selective advantage of different behavioral strategies? The various approaches to this question have fallen into one of the following categories: the fixation probability of a mutant allele in a wild type population, some measures of gene frequency and gene frequency change, and a formulation of the inclusive fitness effect. Countless theoretical studies have examined the relationship between these approaches, and it has generally been thought that, under standard simplifying assumptions, they yield equivalent results. Most of this theoretical work, however, has assumed homogeneity of the population interaction structure--that is, that all individuals are equivalent. We explore the question of selective advantage in a general (heterogeneous) population and show that, although appropriate measures of fixation probability and gene frequency change are equivalent, they are not, in general, equivalent to the inclusive fitness effect. The latter does not reflect effects of selection acting via mutation, which can arise on heterogeneous structures, even for low mutation. Our theoretical framework provides a transparent analysis of the different biological factors at work in the comparison of these fitness measures and suggests that their theoretical and empirical use needs to be revised and carefully grounded in a more general theory.}, } @article {pmid25216091, year = {2014}, author = {Tang, X and Meng, L and Kapranas, A and Xu, F and Hardy, IC and Li, B}, title = {Mutually beneficial host exploitation and ultra-biased sex ratios in quasisocial parasitoids.}, journal = {Nature communications}, volume = {5}, number = {}, pages = {4942}, pmid = {25216091}, issn = {2041-1723}, mesh = {Animals ; Biological Control Agents ; Coleoptera/parasitology ; Female ; Host Specificity ; Larva/parasitology ; Male ; Reproduction/physiology ; Sex Ratio ; *Social Behavior ; Social Environment ; Wasps/*physiology ; }, abstract = {Selfish interests usually preclude resource sharing, but under some conditions collective actions enhance per capita gains. Such Allee effects underlay early explanations of social evolution but current understanding focusses on kin selection (inclusive fitness). We find an Allee effect that explains unusual quasisociality (cooperative brood care) among parasitoid wasps without invoking or precluding kin selection effects. In Sclerodermus harmandi, individual females produce most offspring when exploiting small hosts alone. However, larger hosts are more successfully exploited by larger groups of females, with the per-female benefits outweighing the costs of host sharing. Further, the extremely biased sex ratios (97% female) are better explained by mutually beneficial female-female interactions that increase the reproductive value of daughters (local resource enhancement), rather than by the usually invoked local mate competition between males. Thus, atypical quasisocial behaviour in a parasitoid wasp directly enhances reproductive success and selects for very extremely female-biased sex ratios.}, } @article {pmid25214754, year = {2014}, author = {Kerhoas, D and Perwitasari-Farajallah, D and Agil, M and Widdig, A and Engelhardt, A}, title = {Social and ecological factors influencing offspring survival in wild macaques.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {25}, number = {5}, pages = {1164-1172}, pmid = {25214754}, issn = {1045-2249}, abstract = {Premature loss of offspring decreases direct fitness of parents. In gregarious mammals, both ecological and social variables impact offspring survival and may interact with each other in this regard. Although a number of studies have investigated factors influencing offspring loss in mammals, we still know very little on how different factors interact with one another. We therefore investigated fetal and infant mortality in 3 large groups of wild crested macaques (Macaca nigra) over a period of up to 5 years by including potential social causes such as maternal dominance rank, male immigration, between group encounters, and ecological conditions such as rainfall in a multivariate survival analysis using Cox proportional hazards model. Infant but not fetal survival was most impaired after a recent takeover of the alpha-male position by an immigrant male. Furthermore, infant survival probability increased when there was an increase in number of group adult females and rainfall. Fetal survival probability also increased with an increase of these 2 factors, but more in high-ranking than low-ranking females. Fetal survival, unlike that of infants, was also improved by an increase of intergroup encounter rates. Our study thus stresses the importance of survival analyses using a multivariate approach and encompassing more than a single offspring stage to investigate the determinants of female direct fitness. We further provide evidence for fitness costs and benefits of group living, possibly deriving from high pressures of both within- and between-group competition, in a wild primate population.}, } @article {pmid25183610, year = {2014}, author = {Engelhardt, SC and Weladji, RB and Holand, Ø and de Rioja, CM and Ehmann, RK and Nieminen, M}, title = {Allosuckling in reindeer (Rangifer tarandus): milk-theft, mismothering or kin selection?.}, journal = {Behavioural processes}, volume = {107}, number = {}, pages = {133-141}, doi = {10.1016/j.beproc.2014.08.013}, pmid = {25183610}, issn = {1872-8308}, mesh = {Animals ; Animals, Suckling/*psychology ; Feeding Behavior/*psychology ; Female ; Maternal Behavior/*psychology ; Reindeer/*psychology ; Sucking Behavior/*physiology ; }, abstract = {Allosuckling, the suckling of offspring from females other than their own mother, has been reported in a number of mammalian species, including reindeer. The causes and function of this behaviour are still being investigated. We monitored 25 doe-calf pairs of semi-domestic reindeer Rangifer tarandus over 10 weeks to test three allosuckling/allonursing hypotheses: (1) milk theft, calves opportunistically allosuckle; (2) mismothering, misdirected maternal care; and (3) kin-selected allonursing. A calf soliciting an allosuckling bout was categorized as non-filial (NF), and a calf soliciting a suckling bout from its mother was categorized as filial (F). We recorded 9757 solicitations, of which 5176 were successful F bouts and 1389 were successful NF bouts. The rejection rates were greater for NF than F calves. The proportions of antiparallel positions adopted were greater for F than NF calves. The odds of an allobout were lower for calves arriving 1st, 3rd, 4th, 5th or 6th than for those arriving 2nd, but the odds did not vary with position adopted and relatedness. Our results provided support to the milk-theft hypothesis, whereas limited support for the mismothering hypothesis was found. Our results did not support the hypothesized kin selection function of allosuckling in reindeer. This article is part of a Special Issue entitled: insert SI title.}, } @article {pmid25173619, year = {2014}, author = {Biondo, C and Izar, P and Miyaki, CY and Bussab, VS}, title = {Social structure of collared peccaries (Pecari tajacu): does relatedness matter?.}, journal = {Behavioural processes}, volume = {109 Pt A}, number = {}, pages = {70-78}, doi = {10.1016/j.beproc.2014.08.018}, pmid = {25173619}, issn = {1872-8308}, mesh = {Agonistic Behavior ; Animals ; *Artiodactyla ; Family/*psychology ; Female ; Male ; *Social Behavior ; Spatial Behavior ; }, abstract = {Relatedness is considered an important factor in shaping social structure as the association among kin might facilitate cooperation via inclusive fitness benefits. We addressed here the influence of relatedness on the social structure of a Neotropical ungulate, the collared peccary (Pecari tajacu). As peccaries are highly social and cooperative, live in stable cohesive herds and show certain degree of female philopatry and high mean relatedness within herds, we hypothesized that kin would be spatially closer and display more amicable and less agonistic interactions than non-kin. We recorded spatial association patterns and rates of interactions of two captive groups. Pairwise relatedness was calculated based on microsatellite data. As predicted, we found that kin were spatially closer than non-kin, which suggests that relatedness is a good predictor of spatial association in peccaries. However, relatedness did not predict the rates of social interactions. Although our results indirectly indicate some role of sex, age and familiarity, further studies are needed to clarify the factors that shape the rates of interactions in collared peccaries. This article is part of a Special Issue entitled: Neotropical Behaviour.}, } @article {pmid25165765, year = {2014}, author = {Ferguson-Gow, H and Sumner, S and Bourke, AF and Jones, KE}, title = {Colony size predicts division of labour in attine ants.}, journal = {Proceedings. Biological sciences}, volume = {281}, number = {1793}, pages = {}, pmid = {25165765}, issn = {1471-2954}, mesh = {Animals ; Ants/*physiology ; Appetitive Behavior ; *Behavior, Animal ; Biological Evolution ; Phylogeny ; Population Density ; *Social Behavior ; }, abstract = {Division of labour is central to the ecological success of eusocial insects, yet the evolutionary factors driving increases in complexity in division of labour are little known. The size-complexity hypothesis proposes that, as larger colonies evolve, both non-reproductive and reproductive division of labour become more complex as workers and queens act to maximize inclusive fitness. Using a statistically robust phylogenetic comparative analysis of social and environmental traits of species within the ant tribe Attini, we show that colony size is positively related to both non-reproductive (worker size variation) and reproductive (queen-worker dimorphism) division of labour. The results also suggested that colony size acts on non-reproductive and reproductive division of labour in different ways. Environmental factors, including measures of variation in temperature and precipitation, had no significant effects on any division of labour measure or colony size. Overall, these results support the size-complexity hypothesis for the evolution of social complexity and division of labour in eusocial insects. Determining the evolutionary drivers of colony size may help contribute to our understanding of the evolution of social complexity.}, } @article {pmid25141140, year = {2014}, author = {Alpedrinha, J and Gardner, A and West, SA}, title = {Haplodiploidy and the evolution of eusociality: worker revolution.}, journal = {The American naturalist}, volume = {184}, number = {3}, pages = {303-317}, doi = {10.1086/677283}, pmid = {25141140}, issn = {1537-5323}, mesh = {Altruism ; Animals ; *Biological Evolution ; Female ; *Haploidy ; Hymenoptera/*genetics ; Male ; Models, Biological ; Reproduction ; *Sex Ratio ; *Social Behavior ; }, abstract = {Hamilton suggested that inflated relatedness between sisters promotes the evolution of eusociality in haplodiploid populations. Trivers and Hare observed that for this to occur, workers have to direct helping preferentially toward the production of sisters. Building on this, they proposed two biological scenarios whereby haplodiploidy could act to promote the evolution of eusociality: (a) workers biasing the sex allocation of the queen's brood toward females and (b) workers replacing the queen's sons with their own sons. This "worker revolution," whereby the worker class seizes control of sex allocation and reproduction, is expected to lead to helping being promoted in worker-controlled colonies. Here, we use a kin-selection approach to model the two scenarios suggested by Trivers and Hare. We show that (1) worker control of sex allocation may promote helping, but this effect is likely to be weak and short lived; and (2) worker reproduction tends to inhibit rather than promote helping. Furthermore, the promotion of helping is reduced by a number of biologically likely factors, including the presence of workers increasing colony productivity, workers being unmated, and worker control of sex allocation being underpinned by many loci each having a small effect. Overall, our results suggest that haplodiploidy has had a negligible influence on the evolution of eusociality.}, } @article {pmid25114217, year = {2014}, author = {Wilson, EO and Nowak, MA}, title = {Natural selection drives the evolution of ant life cycles.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {111}, number = {35}, pages = {12585-12590}, pmid = {25114217}, issn = {1091-6490}, mesh = {Animals ; Ants/*genetics ; *Biological Evolution ; Female ; Genetic Fitness ; Male ; *Selection, Genetic ; *Sexual Behavior, Animal ; Social Behavior ; *Sociobiology ; }, abstract = {The genetic origin of advanced social organization has long been one of the outstanding problems of evolutionary biology. Here we present an analysis of the major steps in ant evolution, based for the first time, to our knowledge, on combined recent advances in paleontology, phylogeny, and the study of contemporary life histories. We provide evidence of the causal forces of natural selection shaping several key phenomena: (i) the relative lateness and rarity in geological time of the emergence of eusociality in ants and other animal phylads; (ii) the prevalence of monogamy at the time of evolutionary origin; and (iii) the female-biased sex allocation observed in many ant species. We argue that a clear understanding of the evolution of social insects can emerge if, in addition to relatedness-based arguments, we take into account key factors of natural history and study how natural selection acts on alleles that modify social behavior.}, } @article {pmid25104052, year = {2015}, author = {Zhang, Y and Ji, J and Lin, J and Chen, X and Saito, Y}, title = {Female performance towards offspring under starved conditions in four phytoseiid species (Acari, Phytoseiidae).}, journal = {Experimental & applied acarology}, volume = {65}, number = {1}, pages = {29-41}, pmid = {25104052}, issn = {1572-9702}, mesh = {Animals ; *Cannibalism ; Feeding Behavior ; Female ; Food Deprivation/*physiology ; Mites/*physiology ; Species Specificity ; }, abstract = {There is an important difference between cannibalism between unrelated individuals and between a mother and its offspring, because the former can be defined as a form of intraspecific competition, but the latter affects the inclusive fitness of individuals. Many examples of cannibalism have been reported in predacious phytoseiid mites. Furthermore, sib cannibalism avoidance is known in several species. However, whether females' actually prey upon their offspring under starved conditions has yet to be established. Here, female performance towards their offspring under no-prey-other-than-offspring, water-available and humidity-selectable conditions, was observed in four phytoseiid species, Amblyseius eharai, Amblyseius swirskii, Neoseiulus cucumeris and Typhlodromus bambusae. Typhlodromus bambusae females only survived for 4.14 ± 0.42 days and there was a significant difference in survival duration between T. bambusae and the other three species (all survived more than 8 days). Neoseiulus cucumeris females survived longer than A. eharai and A. swirskii females, whereas there was no difference between A. eharai and A. swirskii females. On the other hand, the offspring (immature stages from egg to larva or protonymph) of A. eharai, A. swirskii and N. cucumeris died earlier in mother-presence than in mother-absence (egg alone) experiments, suggesting that cannibalistic interactions occur between mother and offspring. The survivorship of T. bambusae offspring in the mother-presence condition did not differ from the mother-absence condition, indicating that kin cannibalism is rare in this species. This must be related to the phenomenon that mothers tend to die before their offspring. The short longevity of T. bambusae mothers is one of the reasons why there is no significant difference in immature survival between the mother-presence and mother-absence experiments. Lastly, the reason(s) behind such variation in female phytoseiid performance towards their offspring is addressed in relation to the diet-specialization hypothesis.}, } @article {pmid25081980, year = {2014}, author = {Rice, WR}, title = {An X-linked sex ratio distorter in Drosophila simulans that kills or incapacitates both noncarrier sperm and sons.}, journal = {G3 (Bethesda, Md.)}, volume = {4}, number = {10}, pages = {1837-1848}, pmid = {25081980}, issn = {2160-1836}, support = {R01 HD057974/HD/NICHD NIH HHS/United States ; 1R01HD057974/HD/NICHD NIH HHS/United States ; }, mesh = {Animals ; Drosophila/*genetics ; Evolution, Molecular ; Female ; *Genes, X-Linked ; Male ; Models, Genetic ; *Selection, Genetic ; Sex Ratio ; Spermatozoa/*physiology ; }, abstract = {Genomic conflict occurs when a genomic component gains a reproductive advantage at the expense of the organism as a whole. X-linked segregation distorters kill or incapacitate Y-bearing sperm, thereby gaining a transmission advantage but also reducing male fertility and generating a female-biased sex ratio. When some damaged, Y-bearing sperm survive and fertilize eggs, then the segregation distortion phenotype could be expanded by harming or killing sons in the next generation. X-linked son-killers are predicted by theory to be favored by natural selection and evolve when brothers and sisters compete for shared limiting resources and/or when brothers reduce the inclusive fitness of their sisters via sib-mating-a phenomenon called SA-zygotic drive. Here I develop and use a process-of-elimination screen to show that an unclassified X-linked sex ratio distorter (skew) in Drosophila simulans kills or incapacitates noncarrier sperm and also kills a substantial proportion of sons, i.e., it has both a segregation distortion and a SA-zygotic drive phenotype. There are three unique X-linked segregation distorters known to occur in D. simulans named Winters, Durham, and Paris. Autosomal-dominant suppressors of Winters (Nmy) and Durham (Tmy) failed to suppress skew. A Y-linked suppressor of Paris, however, did suppress skew, and a recombination test failed to detect recombinants between these two sex ratio distorters, indicating that they are tightly linked and plausibly identical or allelic. Son-killing may be an important yet unrecognized component of other X-linked segregation distorters.}, } @article {pmid25065751, year = {2014}, author = {Pfefferle, D and Kazem, AJ and Brockhausen, RR and Ruiz-Lambides, AV and Widdig, A}, title = {Monkeys spontaneously discriminate their unfamiliar paternal kin under natural conditions using facial cues.}, journal = {Current biology : CB}, volume = {24}, number = {15}, pages = {1806-1810}, pmid = {25065751}, issn = {1879-0445}, support = {P40 OD012217/OD/NIH HHS/United States ; 8P40OD012217/OD/NIH HHS/United States ; }, mesh = {Animals ; *Cues ; Face/anatomy & histology ; Female ; Macaca mulatta/*physiology/psychology ; Male ; *Recognition, Psychology ; Siblings ; *Visual Perception ; }, abstract = {Kin recognition can enhance inclusive fitness via nepotism and optimal outbreeding. Mechanisms allowing recognition of patrilineal relatives are of particular interest in species in which females mate promiscuously, leading to paternity uncertainty. Humans are known to detect facial similarities between kin in the faces of third parties, and there is some evidence for continuity of this ability in nonhuman primates . However, no study has yet shown that this propensity translates into an ability to detect one's own relatives, one of the key prerequisites for gaining fitness benefits. Here we report a field experiment demonstrating that free-ranging rhesus macaques (Macaca mulatta) spontaneously discriminate between facial images of their paternal half-siblings and unrelated individuals, when both animals are unfamiliar to the tested individual. Specifically, subjects systematically biased their inspection time toward nonkin when the animals pictured were of their own sex (potential threats), relative to when they were of the opposite sex (potential mates). Our results provide strong evidence for visual phenotype matching and the first demonstration in any primate that individuals can spontaneously detect their own paternal relatives on the basis of facial cues under natural conditions.}, } @article {pmid25039999, year = {2014}, author = {van Dijk, RE and Kaden, JC and Argüelles-Ticó, A and Dawson, DA and Burke, T and Hatchwell, BJ}, title = {Cooperative investment in public goods is kin directed in communal nests of social birds.}, journal = {Ecology letters}, volume = {17}, number = {9}, pages = {1141-1148}, pmid = {25039999}, issn = {1461-0248}, mesh = {Animals ; Cooperative Behavior ; Female ; Male ; Microsatellite Repeats/genetics ; *Social Behavior ; Sparrows/genetics/*physiology ; }, abstract = {The tragedy of the commons predicts social collapse when public goods are jointly exploited by individuals attempting to maximize their fitness at the expense of other social group members. However, animal societies have evolved many times despite this vulnerability to exploitation by selfish individuals. Kin selection offers a solution to this social dilemma, but in large social groups mean relatedness is often low. Sociable weavers (Philetairus socius) live in large colonies that share the benefits of a massive communal nest, which requires individual investment for construction and maintenance. Here, we show that despite low mean kinship within colonies, relatives are spatially and socially clustered and that nest-building males have higher local relatedness to other colony members than do non-building males. Alternative hypotheses received little support, so we conclude that the benefits of the public good are shared with kin and that cooperative investment is, despite the large size and low relatedness of these communities, kin directed.}, } @article {pmid25034338, year = {2014}, author = {van Veelen, M and Luo, S and Simon, B}, title = {A simple model of group selection that cannot be analyzed with inclusive fitness.}, journal = {Journal of theoretical biology}, volume = {360}, number = {}, pages = {279-289}, doi = {10.1016/j.jtbi.2014.07.004}, pmid = {25034338}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Genetic Fitness ; Genetics, Population/*methods ; *Models, Genetic ; *Selection, Genetic ; Time Factors ; }, abstract = {A widespread claim in evolutionary theory is that every group selection model can be recast in terms of inclusive fitness. Although there are interesting classes of group selection models for which this is possible, we show that it is not true in general. With a simple set of group selection models, we show two distinct limitations that prevent recasting in terms of inclusive fitness. The first is a limitation across models. We show that if inclusive fitness is to always give the correct prediction, the definition of relatedness needs to change, continuously, along with changes in the parameters of the model. This results in infinitely many different definitions of relatedness - one for every parameter value - which strips relatedness of its meaning. The second limitation is across time. We show that one can find the trajectory for the group selection model by solving a partial differential equation, and that it is mathematically impossible to do this using inclusive fitness.}, } @article {pmid25033109, year = {2014}, author = {Nowicki, S and Searcy, WA}, title = {The evolution of vocal learning.}, journal = {Current opinion in neurobiology}, volume = {28}, number = {}, pages = {48-53}, doi = {10.1016/j.conb.2014.06.007}, pmid = {25033109}, issn = {1873-6882}, mesh = {Animals ; *Biological Evolution ; Environment ; Humans ; Learning/*physiology ; Sexual Behavior, Animal/physiology ; Vocalization, Animal/*physiology ; }, abstract = {Vocal learning, in which animals modify their vocalizations to imitate those of others, has evolved independently in scattered lineages of birds and mammals. Comparative evidence supports two hypotheses for the selective advantages leading to the origin of vocal learning. The sexual selection hypothesis proposes that vocal learning evolves to allow expansion of vocal repertoires in response to mating preferences for more complex vocalizations. The information-sharing hypothesis also proposes that vocal learning evolves to allow expansion of vocal repertoires, but in this case in response to kin selection favoring sharing of information among relatives.}, } @article {pmid25024637, year = {2014}, author = {Dubuc, C and Ruiz-Lambides, A and Widdig, A}, title = {Variance in male lifetime reproductive success and estimation of the degree of polygyny in a primate.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {25}, number = {4}, pages = {878-889}, pmid = {25024637}, issn = {1045-2249}, abstract = {The degree of polygyny is predicted to influence the strength of direct male-male competition, leading to a high variance in male lifetime reproductive success and to reproduction limited to the prime period of adulthood. Here, we explore the variance in male lifetime reproductive success and reproductive time in an anthropoid primate forming multimale-multifemale groups. Males of this species form dominance hierarchies, which are expected to skew reproduction toward few high-ranking males. At the same time, however, females mate with multiple males (polygynandry), which should limit the degree of polygyny. Using 20 years of genetic and demographic data, we calculated lifetime reproductive success for the free-ranging rhesus macaque (Macaca mulatta) population of Cayo Santiago for subjects that died naturally or reached senescence. Our results show that 1) male lifetime reproductive success was significantly skewed (range: 0-47 offspring; males reproducing below average: 62.8%; nonbreeders: 17.4%), 2) variance in male lifetime reproductive success was 5 times larger than in females, and 3) male lifetime reproductive success was more influenced by variation in fecundity (60%) than longevity (25%), suggesting that some direct male-male competition takes place. However, the opportunity for selection (i.e., standardized variance in male lifetime reproductive success) is low compared with that in other large mammal species characterized by a high degree of polygyny. Moreover, male reproductive life extended much beyond the prime period, showing that physical strength was not required to acquire mates. We conclude that rhesus macaques exhibit a moderate degree of polygyny and, therefore, low levels of direct male-male competition for fertile females, despite the fact that males form linear dominance hierarchies.}, } @article {pmid24970399, year = {2014}, author = {Smaldino, PE}, title = {The cultural evolution of emergent group-level traits.}, journal = {The Behavioral and brain sciences}, volume = {37}, number = {3}, pages = {243-254}, doi = {10.1017/S0140525X13001544}, pmid = {24970399}, issn = {1469-1825}, support = {DP1OD003874/OD/NIH HHS/United States ; }, mesh = {Altruism ; Biological Evolution ; *Cooperative Behavior ; *Cultural Evolution ; *Group Processes ; Humans ; Psychological Theory ; *Selection, Genetic ; }, abstract = {Many of the most important properties of human groups - including properties that may give one group an evolutionary advantage over another - are properly defined only at the level of group organization. Yet at present, most work on the evolution of culture has focused solely on the transmission of individual-level traits. I propose a conceptual extension of the theory of cultural evolution, particularly related to the evolutionary competition between cultural groups. The key concept in this extension is the emergent group-level trait. This type of trait is characterized by the structured organization of differentiated individuals and constitutes a unit of selection that is qualitatively different from selection on groups as defined by traditional multilevel selection (MLS) theory. As a corollary, I argue that the traditional focus on cooperation as the defining feature of human societies has missed an essential feature of cooperative groups. Traditional models of cooperation assume that interacting with one cooperator is equivalent to interacting with any other. However, human groups involve differential roles, meaning that receiving aid from one individual is often preferred to receiving aid from another. In this target article, I discuss the emergence and evolution of group-level traits and the implications for the theory of cultural evolution, including ramifications for the evolution of human cooperation, technology, and cultural institutions, and for the equivalency of multilevel selection and inclusive fitness approaches.}, } @article {pmid24919178, year = {2014}, author = {Podgórski, T and Lusseau, D and Scandura, M and Sönnichsen, L and Jędrzejewska, B}, title = {Long-lasting, kin-directed female interactions in a spatially structured wild boar social network.}, journal = {PloS one}, volume = {9}, number = {6}, pages = {e99875}, pmid = {24919178}, issn = {1932-6203}, mesh = {Animals ; Behavior, Animal/*physiology ; Female ; Genetics, Population ; Group Structure ; Male ; Models, Biological ; Poland ; Sus scrofa/genetics/*physiology ; Telemetry ; }, abstract = {Individuals can increase inclusive fitness benefits through a complex network of social interactions directed towards kin. Preferential relationships with relatives lead to the emergence of kin structures in the social system. Cohesive social groups of related individuals and female philopatry of wild boar create conditions for cooperation through kin selection and make the species a good biological model for studying kin structures. Yet, the role of kinship in shaping the social structure of wild boar populations is still poorly understood. In the present study, we investigated spatio-temporal patterns of associations and the social network structure of the wild boar Sus scrofa population in Białowieża National Park, Poland, which offered a unique opportunity to understand wild boar social interactions away from anthropogenic factors. We used a combination of telemetry data and genetic information to examine the impact of kinship on network cohesion and the strength of social bonds. Relatedness and spatial proximity between individuals were positively related to the strength of social bond. Consequently, the social network was spatially and genetically structured with well-defined and cohesive social units. However, spatial proximity between individuals could not entirely explain the association patterns and network structure. Genuine, kin-targeted, and temporarily stable relationships of females extended beyond spatial proximity between individuals while males interactions were short-lived and not shaped by relatedness. The findings of this study confirm the matrilineal nature of wild boar social structure and show how social preferences of individuals translate into an emergent socio-genetic population structure.}, } @article {pmid24864316, year = {2014}, author = {Bastiaans, E and Aanen, DK and Debets, AJ and Hoekstra, RF and Lestrade, B and Maas, MF}, title = {Regular bottlenecks and restrictions to somatic fusion prevent the accumulation of mitochondrial defects in Neurospora.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1646}, pages = {20130448}, pmid = {24864316}, issn = {1471-2970}, mesh = {Aging/genetics/*physiology ; DNA Replication/genetics/physiology ; DNA, Mitochondrial/genetics/*physiology ; *Genetic Variation ; Mitochondria/genetics/*physiology ; Mutagenesis, Insertional ; Neurospora/genetics/*physiology ; *Selection, Genetic ; }, abstract = {The replication and segregation of multi-copy mitochondrial DNA (mtDNA) are not under strict control of the nuclear DNA. Within-cell selection may thus favour variants with an intracellular selective advantage but a detrimental effect on cell fitness. High relatedness among the mtDNA variants of an individual is predicted to disfavour such deleterious selfish genetic elements, but experimental evidence for this hypothesis is scarce. We studied the effect of mtDNA relatedness on the opportunities for suppressive mtDNA variants in the fungus Neurospora carrying the mitochondrial mutator plasmid pKALILO. During growth, this plasmid integrates into the mitochondrial genome, generating suppressive mtDNA variants. These mtDNA variants gradually replace the wild-type mtDNA, ultimately culminating in growth arrest and death. We show that regular sequestration of mtDNA variation is required for effective selection against suppressive mtDNA variants. First, bottlenecks in the number of mtDNA copies from which a 'Kalilo' culture started significantly increased the maximum lifespan and variation in lifespan among cultures. Second, restrictions to somatic fusion among fungal individuals, either by using anastomosis-deficient mutants or by generating allotype diversity, prevented the accumulation of suppressive mtDNA variants. We discuss the implications of these results for the somatic accumulation of mitochondrial defects during ageing.}, } @article {pmid24852014, year = {2014}, author = {Mitteldorf, J}, title = {Evolutionary orthodoxy: how and why the evolutionary theory of aging went astray.}, journal = {Current aging science}, volume = {7}, number = {1}, pages = {38-47}, doi = {10.2174/1874609807666140521105844}, pmid = {24852014}, issn = {1874-6128}, mesh = {Adaptation, Physiological ; Aging/genetics/*physiology ; Animals ; *Biological Evolution ; Genetic Variation ; Genetics, Population ; Genotype ; Humans ; *Models, Biological ; Models, Genetic ; Mutation ; Phenotype ; Selection, Genetic ; Time Factors ; }, abstract = {Prevailing ideas of how aging evolved are a poor fit with the picture of aging that is developing from genetics labs and breeding experiments. Nevertheless, the community of theorists is reluctant to consider alternate approaches because the differences are profound, calling into question much of the standard methodology of Population Genetics. (At stake is not the legacy of Darwin, but the particular model of Darwinian selection that has dominated the field of research since the middle of the 20th Century). This model may be a historic artifact, arising from a time before computers, when a premium was placed on equations that could be solved analytically. The standard Population Genetic model gained credibility through agreement with laboratory experiments that were designed to realize the assumptions of the model, rather than to mirror conditions in the natural world. Models of evolution based on pure individual selection or inclusive fitness cannot explain the basic phenomenology of aging. Aging is not the only area of conflict, however. Other areas which present difficulties for the standard model include the origin of sex, the maintenance of diversity, the basis of evolvability (including hierarchical structure of the genome), occasional persistence of eusociality without close relatedness, and many examples of strong altruism. From many corners of the field, creative and visionary biologists are calling for a re-thinking of the fundamental mechanisms of natural selection.}, } @article {pmid24810968, year = {2014}, author = {Haig, D}, title = {Does microchimerism mediate kin conflicts?.}, journal = {Chimerism}, volume = {5}, number = {2}, pages = {53-55}, pmid = {24810968}, issn = {1938-1964}, mesh = {*Birth Intervals ; *Chimerism ; Female ; Fetus/*cytology ; Haplotypes ; Humans ; Male ; *Siblings ; }, abstract = {Fetal microchimerism (FMc) is predicted to promote the fitness of the fetus and maternal microchimerism (MMc) to promote the fitness of the mother. Offspring and mothers benefit from each other's health. Therefore, microchimeric cells should usually not be harmful to their host. However, the evolutionary interests of mothers and offspring diverge when there is competition among siblings for maternal investment. Fetal cells in mothers' bodies could benefit their own offspring at the expense of its sibs by promoting lactogenesis or by extending the interbirth interval. Maternal cells in fetal bodies could benefit from the suppression of sibling rivalry. Non-inherited haplotypes in MMc or sibling microchimerism (SMc) gain no direct benefit from their hosts' health and could be associated with substantial detrimental effects.}, } @article {pmid24795846, year = {2014}, author = {Frank, SA}, title = {Microbial metabolism: optimal control of uptake versus synthesis.}, journal = {PeerJ}, volume = {2}, number = {}, pages = {e267}, pmid = {24795846}, issn = {2167-8359}, abstract = {Microbes require several complex organic molecules for growth. A species may obtain a required factor by taking up molecules released by other species or by synthesizing the molecule. The patterns of uptake and synthesis set a flow of resources through the multiple species that create a microbial community. This article analyzes a simple mathematical model of the tradeoff between uptake and synthesis. Key factors include the influx rate from external sources relative to the outflux rate, the rate of internal decay within cells, and the cost of synthesis. Aspects of demography also matter, such as cellular birth and death rates, the expected time course of a local resource flow, and the associated lifespan of the local population. Spatial patterns of genetic variability and differentiation between populations may also strongly influence the evolution of metabolic regulatory controls of individual species and thus the structuring of microbial communities. The widespread use of optimality approaches in recent work on microbial metabolism has ignored demography and genetic structure.}, } @article {pmid24776094, year = {2014}, author = {Gleichsner, AM and Minchella, DJ}, title = {Can host ecology and kin selection predict parasite virulence?.}, journal = {Parasitology}, volume = {141}, number = {8}, pages = {1018-1030}, doi = {10.1017/S0031182014000389}, pmid = {24776094}, issn = {1469-8161}, mesh = {Animals ; Biological Evolution ; Ecology ; Genetic Variation ; Genetics, Population ; *Host-Parasite Interactions ; Humans ; Parasites/genetics/*pathogenicity/physiology ; Virulence/genetics ; }, abstract = {Parasite virulence, or the damage a parasite does to its host, is measured in terms of both host costs (reductions in host growth, reproduction and survival) and parasite benefits (increased transmission and parasite numbers) in the literature. Much work has shown that ecological and genetic factors can be strong selective forces in virulence evolution. This review uses kin selection theory to explore how variations in host ecological parameters impact the genetic relatedness of parasite populations and thus virulence. We provide a broad overview of virulence and population genetics studies and then draw connections to existing knowledge about natural parasite populations. The impact of host movement (transporting parasites) and host resistance (filtering parasites) on the genetic structure and virulence of parasite populations is explored, and empirical studies of these factors using Plasmodium and trematode systems are proposed.}, } @article {pmid24773069, year = {2014}, author = {Davies, NG and Gardner, A}, title = {Evolution of paternal care in diploid and haplodiploid populations.}, journal = {Journal of evolutionary biology}, volume = {27}, number = {6}, pages = {1012-1019}, doi = {10.1111/jeb.12375}, pmid = {24773069}, issn = {1420-9101}, mesh = {Altruism ; Animals ; *Biological Evolution ; *Diploidy ; Female ; *Haploidy ; Hymenoptera/genetics/*physiology ; Male ; Models, Biological ; *Paternal Behavior ; Social Behavior ; }, abstract = {W. D. Hamilton famously suggested that the inflated relatedness of full sisters under haplodiploidy explains why all workers in the social hymenoptera are female. This suggestion has not stood up to further theoretical scrutiny and is not empirically supported. Rather, it appears that altruistic sib-rearing in the social hymenoptera is performed exclusively by females because this behaviour has its origins in parental care, which was performed exclusively by females in the ancestors of this insect group. However, haplodiploidy might still explain the sex of workers if this mode of inheritance has itself been responsible for the rarity of paternal care in this group. Here, we perform a theoretical kin selection analysis to investigate the evolution of paternal care in diploid and haplodiploid populations. We find that haplodiploidy may either inhibit or promote paternal care depending on model assumptions, but that under the most plausible scenarios it promotes - rather than inhibits - paternal care. Our analysis casts further doubt upon there being a causal link between haplodiploidy and eusociality.}, } @article {pmid24762776, year = {2014}, author = {Zee, PC and Bever, JD}, title = {Joint evolution of kin recognition and cooperation in spatially structured rhizobium populations.}, journal = {PloS one}, volume = {9}, number = {4}, pages = {e95141}, pmid = {24762776}, issn = {1932-6203}, support = {R01 GM092660/GM/NIGMS NIH HHS/United States ; T32 GM007757/GM/NIGMS NIH HHS/United States ; 5 R01 GM092660/GM/NIGMS NIH HHS/United States ; T32-GM007757/GM/NIGMS NIH HHS/United States ; }, mesh = {Biological Evolution ; Fabaceae/*microbiology ; Genes, Bacterial ; Genetic Linkage ; Genetic Loci ; Inositol/analogs & derivatives/genetics ; Models, Genetic ; Nitrogen Fixation ; Plant Root Nodulation ; Rhizobium/*genetics ; Symbiosis ; }, abstract = {In the face of costs, cooperative interactions maintained over evolutionary time present a central question in biology. What forces maintain this cooperation? Two potential ways to explain this problem are spatially structured environments (kin selection) and kin-recognition (directed benefits). In a two-locus population genetic model, we investigated the relative roles of spatial structure and kin recognition in the maintenance of cooperation among rhizobia within the rhizobia-legume mutualism. In the case where the cooperative and kin recognition loci are independently inherited, spatial structure alone maintains cooperation, while kin recognition decreases the equilibrium frequency of cooperators. In the case of co-inheritance, spatial structure remains a stronger force, but kin recognition can transiently increase the frequency of cooperators. Our results suggest that spatial structure can be a dominant force in maintaining cooperation in rhizobium populations, providing a mechanism for maintaining the mutualistic nodulation trait. Further, our model generates unique and testable predictions that could be evaluated empirically within the legume-rhizobium mutualism.}, } @article {pmid24747068, year = {2014}, author = {Shukla, S and Pareek, V and Gadagkar, R}, title = {Ovarian development in a primitively eusocial wasp: social interactions affect behaviorally dominant and subordinate wasps in opposite directions relative to solitary females.}, journal = {Behavioural processes}, volume = {106}, number = {}, pages = {22-26}, doi = {10.1016/j.beproc.2014.04.003}, pmid = {24747068}, issn = {1872-8308}, mesh = {Animals ; Behavior, Animal/*physiology ; *Dominance-Subordination ; Female ; Ovary/*growth & development ; Wasps/*physiology ; }, abstract = {In many primitively eusocial wasp species new nests are founded either by a single female or by a small group of females. In the single foundress nests, the lone female develops her ovaries, lays eggs as well as tends her brood. In multiple foundress nests social interactions, especially dominance-subordinate interactions, result in only one 'dominant' female developing her ovaries and laying eggs. Ovaries of the remaining 'subordinate' cofoundresses remain suppressed and these individuals function as workers and tend the dominant's brood. Using the tropical, primitively eusocial polistine wasp Ropalidia marginata and by comparing wasps held in isolation and those kept as pairs in the laboratory, we demonstrate that social interactions affect ovarian development of dominant and subordinate wasps among the pairs in opposite directions, suppressing the ovaries of the subordinate member of the pair below that of solitary wasps and boosting the ovaries of dominant member of the pair above that of solitary females. In addition to being of physiological interest, such mirror image effects of aggression on the ovaries of the aggressors and their victims, suggest yet another mechanism by which subordinates can enhance their indirect fitness and facilitate the evolution of worker behavior by kin selection.}, } @article {pmid24736162, year = {2014}, author = {Pievani, T}, title = {Individuals and groups in evolution: Darwinian pluralism and the multilevel selection debate.}, journal = {Journal of biosciences}, volume = {39}, number = {2}, pages = {319-325}, pmid = {24736162}, issn = {0973-7138}, mesh = {Animals ; *Biological Evolution ; Cultural Diversity ; Humans ; Models, Biological ; Selection, Genetic ; Social Behavior ; }, abstract = {Outlined here is an updated review of the long-standing 'kin selection vs group selection' debate. Group selection is a highly contentious concept, scientifically and philosophically. In 2012, Dawkins' attack against Wilson's latest book about eusociality concentrated all the attention on group selection and its mutual exclusivity with respect to inclusive fitness theory. Both opponents seem to be wrong, facing the general consensus in the field, which favours a pluralistic approach. Historically, despite some misunderstandings in current literature, such a perspective is clearly rooted in Darwin's writings, which suggested a plurality of levels of selection and a general view that we propose to call 'imperfect selfishness'. Today, the mathematically updated hypothesis of group selection has little to do with earlier versions of 'group selection'. It does not imply ontologically unmanageable notions of 'groups'. We propose here population structure as the main criterion of compatibility between kin selection and group selection. The latter is now evidently a pattern among others within a more general 'multilevel selection' theory. Different explanations and patterns are not mutually exclusive. Such a Darwinian pluralism is not a piece of the past, but a path into the future. A challenge in philosophy of biology will be to figure out the logical structure of this emerging pluralistic theory of evolution in such contentious debates.}, } @article {pmid24686941, year = {2014}, author = {Hatchwell, BJ and Gullett, PR and Adams, MJ}, title = {Helping in cooperatively breeding long-tailed tits: a test of Hamilton's rule.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130565}, pmid = {24686941}, issn = {1471-2970}, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Cooperative Behavior ; Genetic Fitness/*genetics ; *Models, Genetic ; Nesting Behavior/*physiology ; Passeriformes/*physiology ; }, abstract = {Inclusive fitness theory provides the conceptual framework for our current understanding of social evolution, and empirical studies suggest that kin selection is a critical process in the evolution of animal sociality. A key prediction of inclusive fitness theory is that altruistic behaviour evolves when the costs incurred by an altruist (c) are outweighed by the benefit to the recipient (b), weighted by the relatedness of altruist to recipient (r), i.e. Hamilton's rule rb > c. Despite its central importance in social evolution theory, there have been relatively few empirical tests of Hamilton's rule, and hardly any among cooperatively breeding vertebrates, leading some authors to question its utility. Here, we use data from a long-term study of cooperatively breeding long-tailed tits Aegithalos caudatus to examine whether helping behaviour satisfies Hamilton's condition for the evolution of altruism. We show that helpers are altruistic because they incur survival costs through the provision of alloparental care for offspring. However, they also accrue substantial benefits through increased survival of related breeders and offspring, and despite the low average relatedness of helpers to recipients, these benefits of helping outweigh the costs incurred. We conclude that Hamilton's rule for the evolution of altruistic helping behaviour is satisfied in this species.}, } @article {pmid24686940, year = {2014}, author = {Queller, DC}, title = {Joint phenotypes, evolutionary conflict and the fundamental theorem of natural selection.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130423}, pmid = {24686940}, issn = {1471-2970}, mesh = {*Biological Evolution ; *Genetic Fitness ; *Models, Genetic ; *Phenotype ; *Selection, Genetic ; Species Specificity ; }, abstract = {Multiple organisms can sometimes affect a common phenotype. For example, the portion of a leaf eaten by an insect is a joint phenotype of the plant and insect and the amount of food obtained by an offspring can be a joint trait with its mother. Here, I describe the evolution of joint phenotypes in quantitative genetic terms. A joint phenotype for multiple species evolves as the sum of additive genetic variances in each species, weighted by the selection on each species. Selective conflict between the interactants occurs when selection takes opposite signs on the joint phenotype. The mean fitness of a population changes not just through its own genetic variance but also through the genetic variance for its fitness that resides in other species, an update of Fisher's fundamental theorem of natural selection. Some similar results, using inclusive fitness, apply to within-species interactions. The models provide a framework for understanding evolutionary conflicts at all levels.}, } @article {pmid24686938, year = {2014}, author = {Kiers, ET and Denison, RF}, title = {Inclusive fitness in agriculture.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130367}, pmid = {24686938}, issn = {1471-2970}, mesh = {*Biological Evolution ; Breeding/*methods ; Crops, Agricultural/*genetics/*growth & development/microbiology ; *Genetic Fitness ; Humans ; Mycorrhizae/genetics/physiology ; Rhizobiaceae/genetics/physiology ; *Selection, Genetic ; Species Specificity ; *Symbiosis ; }, abstract = {Trade-offs between individual fitness and the collective performance of crop and below-ground symbiont communities are common in agriculture. Plant competitiveness for light and soil resources is key to individual fitness, but higher investments in stems and roots by a plant community to compete for those resources ultimately reduce crop yields. Similarly, rhizobia and mycorrhizal fungi may increase their individual fitness by diverting resources to their own reproduction, even if they could have benefited collectively by providing their shared crop host with more nitrogen and phosphorus, respectively. Past selection for inclusive fitness (benefits to others, weighted by their relatedness) is unlikely to have favoured community performance over individual fitness. The limited evidence for kin recognition in plants and microbes changes this conclusion only slightly. We therefore argue that there is still ample opportunity for human-imposed selection to improve cooperation among crop plants and their symbionts so that they use limited resources more efficiently. This evolutionarily informed approach will require a better understanding of how interactions among crops, and interactions with their symbionts, affected their inclusive fitness in the past and what that implies for current interactions.}, } @article {pmid24686937, year = {2014}, author = {Crespi, B and Foster, K and Úbeda, F}, title = {First principles of Hamiltonian medicine.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130366}, pmid = {24686937}, issn = {1471-2970}, mesh = {*Biological Evolution ; Disease/*genetics ; Genes/*genetics ; *Genetic Fitness ; Humans ; Medicine/*methods/trends ; Microbial Interactions/*genetics ; Models, Genetic ; *Social Behavior ; Virulence ; }, abstract = {We introduce the field of Hamiltonian medicine, which centres on the roles of genetic relatedness in human health and disease. Hamiltonian medicine represents the application of basic social-evolution theory, for interactions involving kinship, to core issues in medicine such as pathogens, cancer, optimal growth and mental illness. It encompasses three domains, which involve conflict and cooperation between: (i) microbes or cancer cells, within humans, (ii) genes expressed in humans, (iii) human individuals. A set of six core principles, based on these domains and their interfaces, serves to conceptually organize the field, and contextualize illustrative examples. The primary usefulness of Hamiltonian medicine is that, like Darwinian medicine more generally, it provides novel insights into what data will be productive to collect, to address important clinical and public health problems. Our synthesis of this nascent field is intended predominantly for evolutionary and behavioural biologists who aspire to address questions directly relevant to human health and disease.}, } @article {pmid24686936, year = {2014}, author = {Leggett, HC and Brown, SP and Reece, SE}, title = {War and peace: social interactions in infections.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130365}, pmid = {24686936}, issn = {1471-2970}, support = {095831//Wellcome Trust/United Kingdom ; WT082234MA/WT_/Wellcome Trust/United Kingdom ; /BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Biological Evolution ; *Genetic Fitness ; *Host-Pathogen Interactions ; Infections/*physiopathology ; Microbial Interactions/*genetics ; *Models, Biological ; Phenotype ; *Social Behavior ; Virulence/genetics ; }, abstract = {One of the most striking facts about parasites and microbial pathogens that has emerged in the fields of social evolution and disease ecology in the past few decades is that these simple organisms have complex social lives, indulging in a variety of cooperative, communicative and coordinated behaviours. These organisms have provided elegant experimental tests of the importance of relatedness, kin discrimination, cooperation and competition, in driving the evolution of social strategies. Here, we briefly review the social behaviours of parasites and microbial pathogens, including their contributions to virulence, and outline how inclusive fitness theory has helped to explain their evolution. We then take a mechanistically inspired 'bottom-up' approach, discussing how key aspects of the ways in which parasites and pathogens exploit hosts, namely public goods, mobile elements, phenotypic plasticity, spatial structure and multi-species interactions, contribute to the emergent properties of virulence and transmission. We argue that unravelling the complexities of within-host ecology is interesting in its own right, and also needs to be better incorporated into theoretical evolution studies if social behaviours are to be understood and used to control the spread and severity of infectious diseases.}, } @article {pmid24686934, year = {2014}, author = {Bourke, AF}, title = {Hamilton's rule and the causes of social evolution.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130362}, pmid = {24686934}, issn = {1471-2970}, mesh = {Altruism ; Animals ; *Biological Evolution ; Birds ; *Cooperative Behavior ; *Genetic Fitness ; *Hierarchy, Social ; Insecta ; Mammals ; Phylogeny ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Hamilton's rule is a central theorem of inclusive fitness (kin selection) theory and predicts that social behaviour evolves under specific combinations of relatedness, benefit and cost. This review provides evidence for Hamilton's rule by presenting novel syntheses of results from two kinds of study in diverse taxa, including cooperatively breeding birds and mammals and eusocial insects. These are, first, studies that empirically parametrize Hamilton's rule in natural populations and, second, comparative phylogenetic analyses of the genetic, life-history and ecological correlates of sociality. Studies parametrizing Hamilton's rule are not rare and demonstrate quantitatively that (i) altruism (net loss of direct fitness) occurs even when sociality is facultative, (ii) in most cases, altruism is under positive selection via indirect fitness benefits that exceed direct fitness costs and (iii) social behaviour commonly generates indirect benefits by enhancing the productivity or survivorship of kin. Comparative phylogenetic analyses show that cooperative breeding and eusociality are promoted by (i) high relatedness and monogamy and, potentially, by (ii) life-history factors facilitating family structure and high benefits of helping and (iii) ecological factors generating low costs of social behaviour. Overall, the focal studies strongly confirm the predictions of Hamilton's rule regarding conditions for social evolution and their causes.}, } @article {pmid24686933, year = {2014}, author = {Wild, G and Koykka, C}, title = {Inclusive-fitness logic of cooperative breeding with benefits of natal philopatry.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130361}, pmid = {24686933}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; Competitive Behavior/physiology ; Computer Simulation ; *Cooperative Behavior ; Genetic Fitness/*physiology ; *Models, Biological ; Nesting Behavior/*physiology ; Population Dynamics ; *Territoriality ; }, abstract = {In cooperatively breeding species, individuals help to raise offspring that are not their own. We use two inclusive-fitness models to study the advantage of this kind of helpful behaviour in social groups with high reproductive skew. Our first model does not allow for competition among relatives to occur but our second model does. Specifically, our second model assumes a competitive hierarchy among nest-mates, with non-breeding helpers ranked higher than their newborn siblings. For each model, we obtain an expression for the change in inclusive fitness experienced by a helpful individual in a selfish population. The prediction suggested by each expression is confirmed with computer simulation. When model predictions are compared to one another, we find that helping emerges under a broader range of conditions in the second model. Although competition among kin occurs in our second model, we conclude that the life-history features associated with this competition also act to promote the evolutionary transition from solitary to cooperative breeding.}, } @article {pmid24686932, year = {2014}, author = {Taylor, PD and Maciejewski, W}, title = {Hamilton's inclusive fitness in finite-structured populations.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130360}, pmid = {24686932}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; Gene Frequency ; Genetic Fitness/*genetics ; Genetics, Population/*methods ; *Models, Biological ; *Social Behavior ; }, abstract = {Hamilton's formulation of inclusive fitness has been with us for 50 years. During the first 20 of those years attention was largely focused on the evolutionary trajectories of different behaviours, but over the past 20 years interest has been growing in the effect of population structure on the evolution of behaviour and that is our focus here. We discuss the evolutionary journey of the inclusive-fitness effect over this epoch, nurtured as it was in an essentially homogeneous environment (that of 'transitive' structures) having to adapt in different ways to meet the expectations of heterogeneous structures. We pay particular attention to the way in which the theory has managed to adapt the original constructs of relatedness and reproductive value to provide a formulation of inclusive fitness that captures a precise measure of allele-frequency change in finite-structured populations.}, } @article {pmid24686931, year = {2014}, author = {Ohtsuki, H}, title = {Evolutionary dynamics of n-player games played by relatives.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130359}, pmid = {24686931}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; *Game Theory ; Games, Experimental ; Genetics, Population/*methods ; *Models, Biological ; Selection, Genetic/*genetics ; *Social Behavior ; }, abstract = {One of the core concepts in social evolution theory is kin selection. Kin selection provides a perspective to understand how natural selection operates when genetically similar individuals are likely to interact. A family-structured population is an excellent example of this, where relatives are engaged in social interactions. Consequences of such social interactions are often described in game-theoretical frameworks, but there is a growing consensus that a naive inclusive fitness accounting with dyadic relatedness coefficients are of limited use when non-additive fitness effects are essential in those situations. Here, I provide a general framework to analyse multiplayer interactions among relatives. Two important results follow from my analysis. First, it is generally necessary to know the n-tuple genetic association of family members when n individuals are engaged in social interactions. However, as a second result, I found that, for a special class of games, we need only measures of lower-order genetic association to fully describe its evolutionary dynamics. I introduce the concept of degree of the game and show how this degree is related to the degree of genetic association.}, } @article {pmid24686930, year = {2014}, author = {McGlothlin, JW and Wolf, JB and Brodie, ED and Moore, AJ}, title = {Quantitative genetic versions of Hamilton's rule with empirical applications.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130358}, pmid = {24686930}, issn = {1471-2970}, mesh = {*Altruism ; Animals ; Genetic Fitness/*genetics ; Genetics, Population/*methods ; *Models, Biological ; *Phenotype ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Hamilton's theory of inclusive fitness revolutionized our understanding of the evolution of social interactions. Surprisingly, an incorporation of Hamilton's perspective into the quantitative genetic theory of phenotypic evolution has been slow, despite the popularity of quantitative genetics in evolutionary studies. Here, we discuss several versions of Hamilton's rule for social evolution from a quantitative genetic perspective, emphasizing its utility in empirical applications. Although evolutionary quantitative genetics offers methods to measure each of the critical parameters of Hamilton's rule, empirical work has lagged behind theory. In particular, we lack studies of selection on altruistic traits in the wild. Fitness costs and benefits of altruism can be estimated using a simple extension of phenotypic selection analysis that incorporates the traits of social interactants. We also discuss the importance of considering the genetic influence of the social environment, or indirect genetic effects (IGEs), in the context of Hamilton's rule. Research in social evolution has generated an extensive body of empirical work focusing--with good reason--almost solely on relatedness. We argue that quantifying the roles of social and non-social components of selection and IGEs, in addition to relatedness, is now timely and should provide unique additional insights into social evolution.}, } @article {pmid24686929, year = {2014}, author = {Lehmann, L and Rousset, F}, title = {The genetical theory of social behaviour.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130357}, pmid = {24686929}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; *Environment ; Game Theory ; Gene Frequency ; Genetics, Population/*methods ; *Models, Biological ; *Phenotype ; *Selection, Genetic ; *Social Behavior ; }, abstract = {We survey the population genetic basis of social evolution, using a logically consistent set of arguments to cover a wide range of biological scenarios. We start by reconsidering Hamilton's (Hamilton 1964 J. Theoret. Biol. 7, 1-16 (doi:10.1016/0022-5193(64)90038-4)) results for selection on a social trait under the assumptions of additive gene action, weak selection and constant environment and demography. This yields a prediction for the direction of allele frequency change in terms of phenotypic costs and benefits and genealogical concepts of relatedness, which holds for any frequency of the trait in the population, and provides the foundation for further developments and extensions. We then allow for any type of gene interaction within and between individuals, strong selection and fluctuating environments and demography, which may depend on the evolving trait itself. We reach three conclusions pertaining to selection on social behaviours under broad conditions. (i) Selection can be understood by focusing on a one-generation change in mean allele frequency, a computation which underpins the utility of reproductive value weights; (ii) in large populations under the assumptions of additive gene action and weak selection, this change is of constant sign for any allele frequency and is predicted by a phenotypic selection gradient; (iii) under the assumptions of trait substitution sequences, such phenotypic selection gradients suffice to characterize long-term multi-dimensional stochastic evolution, with almost no knowledge about the genetic details underlying the coevolving traits. Having such simple results about the effect of selection regardless of population structure and type of social interactions can help to delineate the common features of distinct biological processes. Finally, we clarify some persistent divergences within social evolution theory, with respect to exactness, synergies, maximization, dynamic sufficiency and the role of genetic arguments.}, } @article {pmid24686928, year = {2014}, author = {Gardner, A and West, SA}, title = {Inclusive fitness: 50 years on.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {369}, number = {1642}, pages = {20130356}, pmid = {24686928}, issn = {1471-2970}, mesh = {Adaptation, Biological/*genetics ; *Biological Evolution ; *Genetic Fitness ; *Models, Biological ; *Selection, Genetic ; }, } @article {pmid24654980, year = {2014}, author = {Grinsted, L and Breuker, CJ and Bilde, T}, title = {Cooperative breeding favors maternal investment in size over number of eggs in spiders.}, journal = {Evolution; international journal of organic evolution}, volume = {68}, number = {7}, pages = {1961-1973}, doi = {10.1111/evo.12411}, pmid = {24654980}, issn = {1558-5646}, mesh = {Animals ; *Breeding ; Clutch Size/*genetics ; Ecosystem ; Female ; Male ; Ovum/cytology ; Phylogeny ; Reproduction/genetics ; *Sexual Behavior, Animal ; Spiders/*genetics/physiology ; }, abstract = {The transition to cooperative breeding may alter maternal investment strategies depending on density of breeders, extent of reproductive skew, and allo-maternal care. Change in optimal investment from solitary to cooperative breeding can be investigated by comparing social species with nonsocial congeners. We tested two hypotheses in a mainly semelparous system: that social, cooperative breeders, compared to subsocial, solitarily breeding congeners, (1) lay fewer and larger eggs because larger offspring compete better for limited resources and become reproducers; (2) induce egg size variation within clutches as a bet-hedging strategy to ensure that some offspring become reproducers. Within two spider genera, Anelosimus and Stegodyphus, we compared species from similar habitats and augmented the results with a mini-meta-analysis of egg numbers depicted in phylogenies. We found that social species indeed laid fewer, larger eggs than subsocials, while egg size variation was low overall, giving no support for bet-hedging. We propose that the transition to cooperative breeding selects for producing few, large offspring because reproductive skew and high density of breeders and young create competition for resources and reproduction. Convergent evolution has shaped maternal strategies similarly in phylogenetically distant species and directed cooperatively breeding spiders to invest in quality rather than quantity of offspring.}, } @article {pmid24647729, year = {2014}, author = {Nonacs, P}, title = {Resolving the evolution of sterile worker castes: a window on the advantages and disadvantages of monogamy.}, journal = {Biology letters}, volume = {10}, number = {3}, pages = {20140089}, pmid = {24647729}, issn = {1744-957X}, mesh = {Animals ; *Biological Evolution ; Hymenoptera/genetics/*physiology ; Models, Biological ; Reproduction ; *Selection, Genetic ; *Sexual Behavior, Animal ; Social Behavior ; }, abstract = {Many social Hymenoptera species have morphologically sterile worker castes. It is proposed that the evolutionary routes to this obligate sterility must pass through a 'monogamy window', because inclusive fitness favours individuals retaining their reproductive totipotency unless they can rear full siblings. Simulated evolution of sterility, however, finds that 'point of view' is critically important. Monogamy is facilitating if sterility is expressed altruistically (i.e. workers defer reproduction to queens), but if sterility results from manipulation by mothers or siblings, monogamy may have no effect or lessen the likelihood of sterility. Overall, the model and data from facultatively eusocial bees suggest that eusociality and sterility are more likely to originate through manipulation than by altruism, casting doubt on a mandatory role for monogamy. Simple kin selection paradigms, such as Hamilton's rule, can also fail to account for significant evolutionary dynamics created by factors, such as population structure, group-level effects or non-random mating patterns. The easy remedy is to always validate apparently insightful predictions from Hamiltonian equations with life-history appropriate genetic models.}, } @article {pmid24641778, year = {2014}, author = {Giosan, C and Cobeanu, O and Mogoase, C and Muresan, V and Malta, LS and Wyka, K and Szentagotai, A}, title = {Evolutionary cognitive therapy versus standard cognitive therapy for depression: a protocol for a blinded, randomized, superiority clinical trial.}, journal = {Trials}, volume = {15}, number = {}, pages = {83}, pmid = {24641778}, issn = {1745-6215}, mesh = {Clinical Protocols ; Cognitive Behavioral Therapy/*methods ; Depression/diagnosis/psychology/*therapy ; Humans ; Psychiatric Status Rating Scales ; *Research Design ; Romania ; Surveys and Questionnaires ; Time Factors ; Treatment Outcome ; }, abstract = {BACKGROUND: Depression is estimated to become the leading cause of disease burden globally by 2030. Despite existing efficacious treatments (both medical and psychotherapeutic), a large proportion of patients do not respond to therapy. Recent insights from evolutionary psychology suggest that, in addition to targeting the proximal causes of depression (for example, targeting dysfunctional beliefs by cognitive behavioral therapy), the distal or evolutionary causes (for example, inclusive fitness) should also be addressed. A randomized superiority trial is conducted to develop and test an evolutionary-driven cognitive therapy protocol for depression, and to compare its efficacy against standard cognitive therapy for depression.

METHODS/DESIGN: Romanian-speaking adults (18 years or older) with elevated Beck Depression Inventory (BDI) scores (>13), current diagnosis of major depressive disorder or major depressive episode (MDD or MDE), and MDD with comorbid dysthymia, as evaluated by the Structured Clinical Interview for DSM-IV (SCID), are included in the study. Participants are randomized to one of two conditions: 1) evolutionary-driven cognitive therapy (ED-CT) or 2) cognitive therapy (CT). Both groups undergo 12 psychotherapy sessions, and data are collected at baseline, mid-treatment, post-treatment, and the 3-month follow-up. Primary outcomes are depressive symptomatology and a categorical diagnosis of depression post-treatment.

DISCUSSION: This randomized trial compares the newly proposed ED-CT with a classic CT protocol for depression. To our knowledge, this is the first attempt to integrate insights from evolutionary theories of depression into the treatment of this condition in a controlled manner. This study can thus add substantially to the body of knowledge on validated treatments for depression.

TRIAL REGISTRATION: Current Controlled Trials ISRCTN64664414The trial was registered in June 2013. The first participant was enrolled on October 3, 2012.}, } @article {pmid24631046, year = {2014}, author = {Wakano, JY and Lehmann, L}, title = {Evolutionary branching in deme-structured populations.}, journal = {Journal of theoretical biology}, volume = {351}, number = {}, pages = {83-95}, doi = {10.1016/j.jtbi.2014.02.036}, pmid = {24631046}, issn = {1095-8541}, mesh = {Algorithms ; Animals ; *Biological Evolution ; Game Theory ; Genetic Drift ; *Models, Genetic ; Mutation ; Population Density ; Population Dynamics ; Selection, Genetic ; }, abstract = {Adaptive dynamics shows that a continuous trait under frequency dependent selection may first converge to a singular point followed by spontaneous transition from a unimodal trait distribution into a bimodal one, which is called "evolutionary branching". Here, we study evolutionary branching in a deme-structured population by constructing a quantitative genetic model for the trait variance dynamics, which allows us to obtain an analytic condition for evolutionary branching. This is first shown to agree with previous conditions for branching expressed in terms of relatedness between interacting individuals within demes and obtained from mutant-resident systems. We then show this branching condition can be markedly simplified when the evolving trait affect fecundity and/or survival, as opposed to affecting population structure, which would occur in the case of the evolution of dispersal. As an application of our model, we evaluate the threshold migration rate below which evolutionary branching cannot occur in a pairwise interaction game. This agrees very well with the individual-based simulation results.}, } @article {pmid24624128, year = {2014}, author = {Bapteste, E}, title = {The origins of microbial adaptations: how introgressive descent, egalitarian evolutionary transitions and expanded kin selection shape the network of life.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {83}, pmid = {24624128}, issn = {1664-302X}, } @article {pmid24621140, year = {2014}, author = {Bichet, C and Penn, DJ and Moodley, Y and Dunoyer, L and Cellier-Holzem, E and Belvalette, M and Grégoire, A and Garnier, S and Sorci, G}, title = {Females tend to prefer genetically similar mates in an island population of house sparrows.}, journal = {BMC evolutionary biology}, volume = {14}, number = {1}, pages = {47}, pmid = {24621140}, issn = {1471-2148}, mesh = {Animals ; Female ; France ; Genes, MHC Class I ; Genetic Variation ; Inbreeding ; Islands ; Male ; *Mating Preference, Animal ; Microsatellite Repeats ; Sparrows/*genetics/physiology ; }, abstract = {BACKGROUND: It is often proposed that females should select genetically dissimilar mates to maximize offspring genetic diversity and avoid inbreeding. Several recent studies have provided mixed evidence, however, and in some instances females seem to prefer genetically similar males. A preference for genetically similar mates can be adaptive if outbreeding depression is more harmful than inbreeding depression or if females gain inclusive fitness benefits by mating with close kin. Here, we investigated genetic compatibility and mating patterns in an insular population of house sparrow (Passer domesticus), over a three-year period, using 12 microsatellite markers and one major histocompability complex (MHC) class I gene. Given the small population size and the distance from the mainland, we expected a reduced gene flow in this insular population and we predicted that females would show mating preferences for genetically dissimilar mates.

RESULTS: Contrary to our expectation, we found that offspring were less genetically diverse (multi-locus heterozygosity) than expected under a random mating, suggesting that females tended to mate with genetically similar males. We found high levels of extra-pair paternity, and offspring sired by extra-pair males had a better fledging success than those sired by the social male. Again, unexpectedly, females tended to be more closely related to extra-pair mates than to their social mates. Our results did not depend on the type of genetic marker used, since microsatellites and MHC genes provided similar results, and we found only little evidence for MHC-dependent mating patterns.

CONCLUSIONS: These results are in agreement with the idea that mating with genetically similar mates can either avoid the disruption of co-adapted genes or confer a benefit in terms of kin selection.}, } @article {pmid24619652, year = {2014}, author = {VanderLaan, DP and Vasey, PL}, title = {Evidence of cognitive biases for maximizing indirect fitness in Samoan fa'afafine.}, journal = {Archives of sexual behavior}, volume = {43}, number = {5}, pages = {1009-1022}, doi = {10.1007/s10508-014-0288-0}, pmid = {24619652}, issn = {1573-2800}, mesh = {Adult ; *Altruism ; Cognition ; Family/psychology ; *Family Relations ; Female ; *Genetic Fitness ; Homosexuality, Male/*psychology ; Humans ; Male ; Sexual Behavior ; }, abstract = {The kin selection hypothesis posits that male androphilia (i.e., sexual attraction to males), although detrimental to reproduction (i.e., direct fitness), has persisted and evolved because androphilic males compensate by increasing their indirect fitness via increased investment in kin. In previous studies, Samoan androphilic males (known locally as fa'afafine) reported elevated avuncular (i.e., uncle-like) tendencies compared to Samoan gynephilic (i.e., sexually attracted to females) men. Their avuncular tendencies were also greater than the materteral (i.e., aunt-like) tendencies of androphilic women. The present study examined whether the avuncular cognition of fa'afafine was enhanced for maximizing indirect fitness. To do so, it examined whether fa'afafine had a stronger propensity than Samoan gynephilic men and androphilic women to invest in kin categories that would result in more reliable and substantive increases in indirect fitness (i.e., young, female kin) in hypothetical investment scenarios. In a forced-choice paradigm, although all individuals showed some degree of bias to invest in adaptive kin categories during non-frivolous investment contexts in which the consequences of investment were relatively non-trivial, fa'afafine showed greater adherence to the predicted pattern. In addition, shifting the context from frivolous investments, in which the consequences of investment were relatively trivial, to non-frivolous investments prompted fa'afafine to exhibit an enhanced preference, relative to Samoan gynephilic men and androphilic women, to invest in adaptive kin categories. These findings were consistent with the kin selection hypothesis and suggest that, although all individuals exhibit cognitive biases for increasing indirect fitness, the avuncular cognition of androphilic males has undergone selective enhancement to maximize the accrual of indirect fitness via kin-directed altruism.}, } @article {pmid24601980, year = {2014}, author = {Pradhan, BB and Chatterjee, S}, title = {Reversible non-genetic phenotypic heterogeneity in bacterial quorum sensing.}, journal = {Molecular microbiology}, volume = {92}, number = {3}, pages = {557-569}, doi = {10.1111/mmi.12575}, pmid = {24601980}, issn = {1365-2958}, mesh = {Acyl-Butyrolactones/metabolism ; Fatty Acids/metabolism ; Phenotype ; Pseudomonas syringae/drug effects/*physiology ; *Quorum Sensing ; Xanthomonas campestris/drug effects/*physiology ; }, abstract = {Bacteria co-ordinate their social behaviour in a density-dependent manner by production of diffusible signal molecules by a process known as quorum sensing (QS). It is generally assumed that in homogenous environments and at high cell density, QS synchronizes cells in the population to perform collective social tasks in unison which maximize the benefit at the inclusive fitness of individuals. However, evolutionary theory predicts that maintaining phenotypic heterogeneity in performing social tasks is advantageous as it can serve as a bet-hedging survival strategy. Using Pseudomonas syringae and Xanthomonas campestris as model organisms, which use two diverse classes of QS signals, we show that two distinct subpopulations of QS-responsive and non-responsive cells exist in the QS-activated population. Addition of excess exogenous QS signal does not significantly alter the distribution of QS-responsive and non-responsive cells in the population. We further show that progeny of cells derived from these subpopulations also exhibited heterogeneous distribution patterns similar to their respective parental strains. Overall, these results support the model that bacteria maintain QS-responsive and non-responsive subpopulations at high cell densities in a bet-hedging strategy to simultaneously perform functions that are both positively and negatively regulated by QS to improve their fitness in fluctuating environments.}, } @article {pmid24573154, year = {2014}, author = {Durand, PM and Choudhury, R and Rashidi, A and Michod, RE}, title = {Programmed death in a unicellular organism has species-specific fitness effects.}, journal = {Biology letters}, volume = {10}, number = {2}, pages = {20131088}, pmid = {24573154}, issn = {1744-957X}, mesh = {*Apoptosis ; Chlamydomonas/genetics/growth & development/*physiology ; *Genetic Fitness ; Hot Temperature ; Species Specificity ; }, abstract = {Programmed cell death (PCD) is an ancient phenomenon and its origin and maintenance in unicellular life is unclear. We report that programmed death provides differential fitness effects that are species specific in the model organism Chlamydomonas reinhardtii. Remarkably, PCD in this organism not only benefits others of the same species, but also has an inhibitory effect on the growth of other species. These data reveal that the fitness effects of PCD can depend upon genetic relatedness.}, } @article {pmid24567830, year = {2013}, author = {Sato, Y and Egas, M and Sabelis, MW and Mochizuki, A}, title = {Male-male aggression peaks at intermediate relatedness in a social spider mite.}, journal = {Ecology and evolution}, volume = {3}, number = {8}, pages = {2661-2669}, pmid = {24567830}, issn = {2045-7758}, abstract = {Theory predicts that when individuals live in groups or colonies, male-male aggression peaks at intermediate levels of local average relatedness. Assuming that aggression is costly and directed toward nonrelatives and that competition for reproduction acts within the colony, benefits of aggressive behavior are maximized in colonies with a mix of related and unrelated competitors because aggression hurts nonkin often, thereby favoring reproduction of kin. This leads to a dome-shaped relation between male-male aggression and average relatedness. This prediction has been tested with bacteria in the laboratory, but not with organisms in the field. We study how male-male aggression varies with relatedness in the social spider mite Stigmaeopsis miscanthi. We sampled 25 populations across a wide geographic range between Taiwan and Japan, representing a gradient of high to low within-population relatedness. For each population the weaponry of males was measured as the length of the first pair of legs, and male-male aggression was tested by placing pairs of nonsibling males together and scoring the frequency of male death over a given period. As these two morphological and behavioral variables correlate strongly, they both reflect the intensity of male-male conflict. Our data on the social spider mite show that male-male aggression as well as weapon size strongly peak at intermediate, average relatedness, thereby confirming theoretical predictions. Inclusive fitness theory predicts that when individuals live in groups or colonies, aggression should peak at intermediate levels of average relatedness in the colony. Here, we study how male-male aggression varies with average relatedness in naturally occurring colonies of the social spider mite Stigmaeopsis miscanthi. In support of theory, male-male aggression and weapon size strongly peak at intermediate average relatedness.}, } @article {pmid24555438, year = {2014}, author = {Kessler, SE and Radespiel, U and Hasiniaina, AI and Leliveld, LM and Nash, LT and Zimmermann, E}, title = {Modeling the origins of mammalian sociality: moderate evidence for matrilineal signatures in mouse lemur vocalizations.}, journal = {Frontiers in zoology}, volume = {11}, number = {1}, pages = {14}, pmid = {24555438}, issn = {1742-9994}, abstract = {INTRODUCTION: Maternal kin selection is a driving force in the evolution of mammalian social complexity and it requires that kin are distinctive from nonkin. The transition from the ancestral state of asociality to the derived state of complex social groups is thought to have occurred via solitary foraging, in which individuals forage alone, but, unlike the asocial ancestors, maintain dispersed social networks via scent-marks and vocalizations. We hypothesize that matrilineal signatures in vocalizations were an important part of these networks. We used the solitary foraging gray mouse lemur (Microcebus murinus) as a model for ancestral solitary foragers and tested for matrilineal signatures in their calls, thus investigating whether such signatures are already present in solitary foragers and could have facilitated the kin selection thought to have driven the evolution of increased social complexity in mammals. Because agonism can be very costly, selection for matrilineal signatures in agonistic calls should help reduce agonism between unfamiliar matrilineal kin. We conducted this study on a well-studied population of wild mouse lemurs at Ankarafantsika National Park, Madagascar. We determined pairwise relatedness using seven microsatellite loci, matrilineal relatedness by sequencing the mitrochondrial D-loop, and sleeping group associations using radio-telemetry. We recorded agonistic calls during controlled social encounters and conducted a multi-parametric acoustic analysis to determine the spectral and temporal structure of the agonistic calls. We measured 10 calls for each of 16 females from six different matrilineal kin groups.

RESULTS: Calls were assigned to their matriline at a rate significantly higher than chance (pDFA: correct = 47.1%, chance = 26.7%, p = 0.03). There was a statistical trend for a negative correlation between acoustic distance and relatedness (Mantel Test: g = -1.61, Z = 4.61, r = -0.13, p = 0.058).

CONCLUSIONS: Mouse lemur agonistic calls are moderately distinctive by matriline. Because sleeping groups consisted of close maternal kin, both genetics and social learning may have generated these acoustic signatures. As mouse lemurs are models for solitary foragers, we recommend further studies testing whether the lemurs use these calls to recognize kin. This would enable further modeling of how kin recognition in ancestral species could have shaped the evolution of complex sociality.}, } @article {pmid24530825, year = {2014}, author = {Okasha, S and Weymark, JA and Bossert, W}, title = {Inclusive fitness maximization: An axiomatic approach.}, journal = {Journal of theoretical biology}, volume = {350}, number = {}, pages = {24-31}, doi = {10.1016/j.jtbi.2014.02.002}, pmid = {24530825}, issn = {1095-8541}, mesh = {*Genetic Fitness ; *Models, Genetic ; }, abstract = {Kin selection theorists argue that evolution in social contexts will lead organisms to behave as if maximizing their inclusive, as opposed to personal, fitness. The inclusive fitness concept allows biologists to treat organisms as akin to rational agents seeking to maximize a utility function. Here we develop this idea and place it on a firm footing by employing a standard decision-theoretic methodology. We show how the principle of inclusive fitness maximization and a related principle of quasi-inclusive fitness maximization can be derived from axioms on an individual׳s 'as if preferences' (binary choices) for the case in which phenotypic effects are additive. Our results help integrate evolutionary theory and rational choice theory, help draw out the behavioural implications of inclusive fitness maximization, and point to a possible way in which evolution could lead organisms to implement it.}, } @article {pmid24504534, year = {2014}, author = {Hesse, S and Thünken, T}, title = {Growth and social behavior in a cichlid fish are affected by social rearing environment and kinship.}, journal = {Die Naturwissenschaften}, volume = {101}, number = {4}, pages = {273-283}, pmid = {24504534}, issn = {1432-1904}, mesh = {Animals ; Behavior, Animal/*physiology ; Cichlids/growth & development/*physiology ; *Social Behavior ; *Social Environment ; }, abstract = {Living in groups is a widespread phenomenon in many animal taxa. The reduction of predation risk is thought to be an important cause for the formation of groups. Consequently, grouping behavior is particularly pronounced during vulnerable life stages, i.e., as juveniles. However, group living does not only provide benefits but also imposes costs on group members, e.g., increased competition for food. Thus, benefits of grouping behavior might not be evident when predation risk is absent. The adaptive significance of living and also developing in a group independent from predation risk has received relatively little attention although this might have important implications on the evolution and maintenance of group living. The first aim of the present study was to examine whether the social environment affects juvenile performance in the cichlid fish Pelvicachromis taeniatus and, secondly, whether kinship affects social behavior. Kin selection theory predicts benefits from grouping with kin. Here, we demonstrate that juveniles reared in a group grow on average faster compared to juveniles reared in isolation under standardized laboratory conditions without predation risk. Furthermore, we found significant differences in social behavior between juveniles reared in a group and reared in isolation. Fish reared in isolation were significantly more aggressive and less willing to shoal than group-reared fish. As expected, genetic relatedness influenced social behavior in group-reared fish as well: dyads of juveniles consisting of kin showed increased group cohesiveness compared to non-kin dyads. We discuss the potential benefits of group living in general and living with kin in particular.}, } @article {pmid24496091, year = {2014}, author = {Gardner, A}, title = {Genomic imprinting and the units of adaptation.}, journal = {Heredity}, volume = {113}, number = {2}, pages = {104-111}, pmid = {24496091}, issn = {1365-2540}, mesh = {*Adaptation, Biological ; Algorithms ; Biological Evolution ; Female ; Genetic Fitness ; Genome ; *Genomic Imprinting ; Genomics ; Humans ; Male ; Models, Genetic ; Selection, Genetic ; }, abstract = {Two guiding principles identify which biological entities are able to evolve adaptations. Williams' principle holds that, in order for an entity to evolve adaptations, there must be selection between such entities. Maynard Smith's principle holds that, in order for an entity to evolve adaptations, selection within such entities must be absent or negligible. However, although the kinship theory of genomic imprinting suggests that parent-of-origin-specific gene expression evolves as a consequence of natural selection acting between--rather than within--individuals, it evades adaptive interpretation at the individual level and is instead viewed as an outcome of an intragenomic conflict of interest between an individual's genes. Here, I formalize the idea that natural selection drives intragenomic conflicts of interest between genes originating from different parents. Specifically, I establish mathematical links between the dynamics of natural selection and the idea of the gene as an intentional, inclusive-fitness-maximizing agent, and I clarify the role that information about parent of origin plays in mediating conflicts of interest between genes residing in the same genome. These results highlight that the suppression of divisive information may be as important as the suppression of lower levels of selection in maintaining the integrity of units of adaptation.}, } @article {pmid24488971, year = {2014}, author = {Harpur, BA and Kent, CF and Molodtsova, D and Lebon, JM and Alqarni, AS and Owayss, AA and Zayed, A}, title = {Population genomics of the honey bee reveals strong signatures of positive selection on worker traits.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {111}, number = {7}, pages = {2614-2619}, pmid = {24488971}, issn = {1091-6490}, mesh = {Adaptation, Biological/*genetics ; Animals ; Base Sequence ; Bees/*genetics ; *Biological Evolution ; *Genetic Variation ; *Hierarchy, Social ; *Metagenomics ; Molecular Sequence Data ; *Selection, Genetic ; Sequence Analysis, DNA ; }, abstract = {Most theories used to explain the evolution of eusociality rest upon two key assumptions: mutations affecting the phenotype of sterile workers evolve by positive selection if the resulting traits benefit fertile kin, and that worker traits provide the primary mechanism allowing social insects to adapt to their environment. Despite the common view that positive selection drives phenotypic evolution of workers, we know very little about the prevalence of positive selection acting on the genomes of eusocial insects. We mapped the footprints of positive selection in Apis mellifera through analysis of 40 individual genomes, allowing us to identify thousands of genes and regulatory sequences with signatures of adaptive evolution over multiple timescales. We found Apoidea- and Apis-specific genes to be enriched for signatures of positive selection, indicating that novel genes play a disproportionately large role in adaptive evolution of eusocial insects. Worker-biased proteins have higher signatures of adaptive evolution relative to queen-biased proteins, supporting the view that worker traits are key to adaptation. We also found genes regulating worker division of labor to be enriched for signs of positive selection. Finally, genes associated with worker behavior based on analysis of brain gene expression were highly enriched for adaptive protein and cis-regulatory evolution. Our study highlights the significant contribution of worker phenotypes to adaptive evolution in social insects, and provides a wealth of knowledge on the loci that influence fitness in honey bees.}, } @article {pmid24486248, year = {2014}, author = {Simon, B}, title = {Continuous-time models of group selection, and the dynamical insufficiency of kin selection models.}, journal = {Journal of theoretical biology}, volume = {349}, number = {}, pages = {22-31}, doi = {10.1016/j.jtbi.2014.01.030}, pmid = {24486248}, issn = {1095-8541}, mesh = {*Models, Theoretical ; Population Dynamics ; Time Factors ; }, abstract = {Traditionally, the process of group selection has been described mathematically by discrete-time models, and analyzed using tools like the Price equation. This approach makes implicit assumptions about the process that are not valid in general, like the central role of synchronized mass-dispersion and group re-formation events. In many important examples (like hunter-gatherer tribes) there are no mass-dispersion events, and the group-level events that do occur, like fission, fusion, and extinction, occur asynchronously. Examples like these can be fully analyzed by the equations of two-level population dynamics (described here) so their models are dynamically sufficient. However, it will be shown that examples like these cannot be fully analyzed by kin selection (inclusive fitness) methods because kin selection versions of group selection models are not dynamically sufficient. This is a critical mathematical difference between group selection and kin selection models, which implies that the two theories are not mathematically equivalent.}, } @article {pmid24480612, year = {2014}, author = {Haig, D}, title = {Interbirth intervals: Intrafamilial, intragenomic and intrasomatic conflict.}, journal = {Evolution, medicine, and public health}, volume = {2014}, number = {1}, pages = {12-17}, pmid = {24480612}, issn = {2050-6201}, abstract = {BACKGROUND AND OBJECTIVES: Interbirth intervals (IBIs) mediate a trade-off between child number and child survival. Life history theory predicts that the evolutionarily optimal IBI differs for different individuals whose fitness is affected by how closely a mother spaces her children. The objective of the article is to clarify these conflicts and explore their implications for public health.

METHODOLOGY: Simple models of inclusive fitness and kin conflict address the evolution of human birth-spacing.

RESULTS: Genes of infants generally favor longer intervals than genes of mothers, and infant genes of paternal origin generally favor longer IBIs than genes of maternal origin.

CONCLUSIONS AND IMPLICATIONS: The colonization of maternal bodies by offspring cells (fetal microchimerism) raises the possibility that cells of older offspring could extend IBIs by interfering with the implantation of subsequent embryos.}, } @article {pmid24463521, year = {2014}, author = {Carazo, P and Tan, CK and Allen, F and Wigby, S and Pizzari, T}, title = {Within-group male relatedness reduces harm to females in Drosophila.}, journal = {Nature}, volume = {505}, number = {7485}, pages = {672-675}, pmid = {24463521}, issn = {1476-4687}, support = {/WT_/Wellcome Trust/United Kingdom ; BB/K014544/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Competitive Behavior/physiology ; *Cooperative Behavior ; Drosophila melanogaster/genetics/*physiology ; Female ; Heredity/physiology ; Longevity/genetics/physiology ; Male ; Models, Biological ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; *Siblings ; }, abstract = {To resolve the mechanisms that switch competition to cooperation is key to understanding biological organization. This is particularly relevant for intrasexual competition, which often leads to males harming females. Recent theory proposes that kin selection may modulate female harm by relaxing competition among male relatives. Here we experimentally manipulate the relatedness of groups of male Drosophila melanogaster competing over females to demonstrate that, as expected, within-group relatedness inhibits male competition and female harm. Females exposed to groups of three brothers unrelated to the female had higher lifetime reproductive success and slower reproductive ageing compared to females exposed to groups of three males unrelated to each other. Triplets of brothers also fought less with each other, courted females less intensively and lived longer than triplets of unrelated males. However, associations among brothers may be vulnerable to invasion by minorities of unrelated males: when two brothers were matched with an unrelated male, the unrelated male sired on average twice as many offspring as either brother. These results demonstrate that relatedness can profoundly affect fitness through its modulation of intrasexual competition, as flies plastically adjust sexual behaviour in a manner consistent with kin-selection theory.}, } @article {pmid24463009, year = {2014}, author = {Foster, NL and Briffa, M}, title = {Familial strife on the seashore: aggression increases with relatedness in the sea anemone Actinia equina.}, journal = {Behavioural processes}, volume = {103}, number = {}, pages = {243-245}, doi = {10.1016/j.beproc.2014.01.009}, pmid = {24463009}, issn = {1872-8308}, mesh = {Aggression/*psychology ; Animals ; Behavior, Animal/*physiology ; Competitive Behavior ; Sea Anemones/*physiology ; Social Environment ; }, abstract = {Pairwise contests occur when two individuals compete directly over ownership of an indivisible resource. Contests vary in the degree of escalation, some encounters being settled through non-injurious behaviour while others are only resolved after dangerous fighting. Here, we investigate the role of relatedness, assessed using AFLP analysis, on the occurrence of stinging during staged contests in the beadlet sea anemone Actinia equina. Contrary to our expectations, we found that the chance of stinging, and hence the chance of inflicting damage, increased with the degree of relatedness between the two opponents. This result may be explained by the negative relationship between asymmetry in fighting ability and escalation level predicted by theory. We suggest that in order to fully understand how relatedness influences aggression, predictions from kin selection theory should be incorporated with those from contest theory.}, } @article {pmid24459698, year = {2014}, author = {Osborne, DL and Hames, R}, title = {A life history perspective on skin cancer and the evolution of skin pigmentation.}, journal = {American journal of physical anthropology}, volume = {153}, number = {1}, pages = {1-8}, doi = {10.1002/ajpa.22408}, pmid = {24459698}, issn = {1096-8644}, mesh = {Adaptation, Physiological ; Age Factors ; *Anthropology, Physical ; *Biological Evolution ; Humans ; *Skin Neoplasms ; *Skin Pigmentation ; Sunlight ; Ultraviolet Rays ; }, abstract = {The ancestral state of human skin pigmentation evolved in response to high ultraviolet radiation (UVR) stress. Some argue that pigmentation evolved to limit folate photolysis, therein limiting neural tube defects. Pigmentation also protects against sunburn which decreases the efficiency of sweating and potentiates skin infection. Pigmentation increases the efficacy of skin as a barrier to infection. Skin cancer has been rejected or minimized as a selective pressure because it is believed to have little or no effect on mortality during reproductive years. This argument ignores evidence of human longevity as a derived life history trait and the adaptive value of investment in offspring and kin, particularly during the post-reproductive lifespan. Opponents argue that lifespan in prehistoric hunter-gatherers was too short to be relevant to the evolution of skin pigmentation. This argument is flawed in that it relies on estimates of longevity at birth rather than adolescence. When appropriate estimates are used, it is clear that human longevity has a deep evolutionary history. We use a life history perspective to demonstrate the value of skin pigmentation as an adaptation to skin cancer with the following points: UVR exposure increases dysregulation of gene expression in skin cells leading to immortal cell lines; cutaneous malignant melanoma (CMM) affects individuals throughout reproductive years; and lifespan was longer than has previously been acknowledged, providing the opportunity for kin selection. This hypothesis is not at odds with the folate or barrier hypotheses. We stress that the evolution of skin pigmentation is complex and is an ongoing process.}, } @article {pmid24374238, year = {2014}, author = {Kobayashi, Y and Ohtsuki, H}, title = {Evolution of social versus individual learning in a subdivided population revisited: comparative analysis of three coexistence mechanisms using the inclusive-fitness method.}, journal = {Theoretical population biology}, volume = {92}, number = {}, pages = {78-87}, doi = {10.1016/j.tpb.2013.12.003}, pmid = {24374238}, issn = {1096-0325}, mesh = {Humans ; *Learning ; *Models, Theoretical ; *Social Behavior ; }, abstract = {Learning abilities are categorized into social (learning from others) and individual learning (learning on one's own). Despite the typically higher cost of individual learning, there are mechanisms that allow stable coexistence of both learning modes in a single population. In this paper, we investigate by means of mathematical modeling how the effect of spatial structure on evolutionary outcomes of pure social and individual learning strategies depends on the mechanisms for coexistence. We model a spatially structured population based on the infinite-island framework and consider three scenarios that differ in coexistence mechanisms. Using the inclusive-fitness method, we derive the equilibrium frequency of social learners and the genetic load of social learning (defined as average fecundity reduction caused by the presence of social learning) in terms of some summary statistics, such as relatedness, for each of the three scenarios and compare the results. This comparative analysis not only reconciles previous models that made contradictory predictions as to the effect of spatial structure on the equilibrium frequency of social learners but also derives a simple mathematical rule that determines the sign of the genetic load (i.e. whether or not social learning contributes to the mean fecundity of the population).}, } @article {pmid24351787, year = {2013}, author = {Aubin, HJ and Berlin, I and Kornreich, C}, title = {The evolutionary puzzle of suicide.}, journal = {International journal of environmental research and public health}, volume = {10}, number = {12}, pages = {6873-6886}, pmid = {24351787}, issn = {1660-4601}, mesh = {Adaptation, Biological ; Altruism ; Animals ; *Biological Evolution ; Conflict, Psychological ; Humans ; Risk Factors ; Stress, Psychological ; Suicide/*psychology ; }, abstract = {Mechanisms of self-destruction are difficult to reconcile with evolution's first rule of thumb: survive and reproduce. However, evolutionary success ultimately depends on inclusive fitness. The altruistic suicide hypothesis posits that the presence of low reproductive potential and burdensomeness toward kin can increase the inclusive fitness payoff of self-removal. The bargaining hypothesis assumes that suicide attempts could function as an honest signal of need. The payoff may be positive if the suicidal person has a low reproductive potential. The parasite manipulation hypothesis is founded on the rodent-Toxoplasma gondii host-parasite model, in which the parasite induces a "suicidal" feline attraction that allows the parasite to complete its life cycle. Interestingly, latent infection by T. gondii has been shown to cause behavioral alterations in humans, including increased suicide attempts. Finally, we discuss how suicide risk factors can be understood as nonadaptive byproducts of evolved mechanisms that malfunction. Although most of the mechanisms proposed in this article are largely speculative, the hypotheses that we raise accept self-destructive behavior within the framework of evolutionary theory.}, } @article {pmid24332540, year = {2014}, author = {Drescher, K and Nadell, CD and Stone, HA and Wingreen, NS and Bassler, BL}, title = {Solutions to the public goods dilemma in bacterial biofilms.}, journal = {Current biology : CB}, volume = {24}, number = {1}, pages = {50-55}, pmid = {24332540}, issn = {1879-0445}, support = {/HHMI_/Howard Hughes Medical Institute/United States ; R01 GM065859/GM/NIGMS NIH HHS/United States ; 5R01GM065859/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biofilms ; Chitin/metabolism ; Chitinases/metabolism ; Gene Expression Regulation, Enzymologic ; RNA, Messenger/biosynthesis ; Vibrio cholerae/*physiology ; }, abstract = {Bacteria frequently live in densely populated surface-bound communities, termed biofilms [1-4]. Biofilm-dwelling cells rely on secretion of extracellular substances to construct their communities and to capture nutrients from the environment [5]. Some secreted factors behave as cooperative public goods: they can be exploited by nonproducing cells [6-11]. The means by which public-good-producing bacteria avert exploitation in biofilm environments are largely unknown. Using experiments with Vibrio cholerae, which secretes extracellular enzymes to digest its primary food source, the solid polymer chitin, we show that the public goods dilemma may be solved by two very different mechanisms: cells can produce thick biofilms that confine the goods to producers, or fluid flow can remove soluble products of chitin digestion, denying access to nonproducers. Both processes are unified by limiting the distance over which enzyme-secreting cells provide benefits to neighbors, resulting in preferential benefit to nearby clonemates and allowing kin selection to favor public good production. Our results demonstrate new mechanisms by which the physical conditions of natural habitats can interact with bacterial physiology to promote the evolution of cooperation.}, } @article {pmid24329934, year = {2014}, author = {El Mouden, C and André, JB and Morin, O and Nettle, D}, title = {Cultural transmission and the evolution of human behaviour: a general approach based on the Price equation.}, journal = {Journal of evolutionary biology}, volume = {27}, number = {2}, pages = {231-241}, doi = {10.1111/jeb.12296}, pmid = {24329934}, issn = {1420-9101}, mesh = {Altruism ; *Behavior ; *Biological Evolution ; *Cultural Evolution ; Humans ; *Models, Theoretical ; Selection, Genetic ; }, abstract = {Transmitted culture can be viewed as an inheritance system somewhat independent of genes that is subject to processes of descent with modification in its own right. Although many authors have conceptualized cultural change as a Darwinian process, there is no generally agreed formal framework for defining key concepts such as natural selection, fitness, relatedness and altruism for the cultural case. Here, we present and explore such a framework using the Price equation. Assuming an isolated, independently measurable culturally transmitted trait, we show that cultural natural selection maximizes cultural fitness, a distinct quantity from genetic fitness, and also that cultural relatedness and cultural altruism are not reducible to or necessarily related to their genetic counterparts. We show that antagonistic coevolution will occur between genes and culture whenever cultural fitness is not perfectly aligned with genetic fitness, as genetic selection will shape psychological mechanisms to avoid susceptibility to cultural traits that bear a genetic fitness cost. We discuss the difficulties with conceptualizing cultural change using the framework of evolutionary theory, the degree to which cultural evolution is autonomous from genetic evolution, and the extent to which cultural change should be seen as a Darwinian process. We argue that the nonselection components of evolutionary change are much more important for culture than for genes, and that this and other important differences from the genetic case mean that different approaches and emphases are needed for cultural than genetic processes.}, } @article {pmid24320989, year = {2014}, author = {Úbeda, F and Ohtsuki, H and Gardner, A}, title = {Ecology drives intragenomic conflict over menopause.}, journal = {Ecology letters}, volume = {17}, number = {2}, pages = {165-174}, pmid = {24320989}, issn = {1461-0248}, mesh = {Aged ; Aging/genetics ; Animals ; Culture ; Female ; Fertility/genetics/physiology ; Gene Expression Regulation ; *Genome, Human ; Humans ; Male ; Maternal Age ; Menopause/*genetics/physiology ; Middle Aged ; *Models, Genetic ; }, abstract = {Menopause is the transition from reproductive to non-reproductive life well before natural death. Rather than involving a smooth, rapid change, it is normally preceded by a long period of erratic hormonal fluctuation that is accompanied by a plethora of unpleasant symptoms. Here, we (1) suggest that this turbulent period owes to conflict, between a woman's maternally inherited (MI) and paternally inherited (PI) genes, over the trade-off between reproduction and communal care; (2) perform a theoretical analysis to show that this conflict is resolved either through silencing or fluctuating expression of one of the genes; (3) highlight which of the symptoms preceding menopause may result from antagonistic co-evolution of MI and PI genes; (4) argue that ecological differences between ancestral human populations may explain the variability in menopause among different ethnic groups; (5) discuss how these insights may be used to inform family planning and cancer risk assessment based on a woman's ancestral background.}, } @article {pmid24277978, year = {2013}, author = {Schaedelin, FC and van Dongen, WF and Wagner, RH}, title = {Non-random brood mixing suggests adoption in a colonial cichlid.}, journal = {Behavioral ecology : official journal of the International Society for Behavioral Ecology}, volume = {24}, number = {2}, pages = {}, pmid = {24277978}, issn = {1045-2249}, support = {P 20401/FWF_/Austrian Science Fund FWF/Austria ; }, abstract = {Parental care of unrelated offspring is widespread but not well understood. We used 11 polymorphic microsatellite loci to investigate the relatedness of fry and parentally caring adults in a 118-nest colony of the socially and genetically monogamous cichlid fish Neolamprologus caudopunctatus in Lake Tanganyika. There was a high proportion of brood mixing, with 59% of 32 broods containing fry unrelated to both parents, and 18% of all 291 sampled fry being unrelated to the breeding pair. There was no evidence of kin selection for adoption because the genetic and foster parents were not more related than expected by chance. Parentage was assigned to 12 adopted fry from 10 broods. Distances traversed by fry varied markedly, from less than one to over 40 meters. The larger distances suggest that at least some brood mixing was instigated by parents transporting portions of their broods in their mouths, as occurs in some cichlids. Further evidence of non-random brood mixing was that foreign fry did not differ in size from their foster siblings within broods, even though they were significantly larger than fry produced by the tending pairs within the colony. These findings suggest that at least some foreign fry had dispersed non-randomly and were adopted by their foster parents. Enlarged broods are known to provide reduced per capita predation, making it potentially adaptive for breeders to adopt unrelated offspring.}, } @article {pmid24277847, year = {2013}, author = {Allen, B and Nowak, MA and Wilson, EO}, title = {Limitations of inclusive fitness.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {110}, number = {50}, pages = {20135-20139}, pmid = {24277847}, issn = {1091-6490}, mesh = {*Biological Evolution ; Data Interpretation, Statistical ; Gene Frequency ; Genetic Fitness/*genetics ; Genetics, Population/*methods ; *Models, Genetic ; Regression Analysis ; *Social Behavior ; }, abstract = {Until recently, inclusive fitness has been widely accepted as a general method to explain the evolution of social behavior. Affirming and expanding earlier criticism, we demonstrate that inclusive fitness is instead a limited concept, which exists only for a small subset of evolutionary processes. Inclusive fitness assumes that personal fitness is the sum of additive components caused by individual actions. This assumption does not hold for the majority of evolutionary processes or scenarios. To sidestep this limitation, inclusive fitness theorists have proposed a method using linear regression. On the basis of this method, it is claimed that inclusive fitness theory (i) predicts the direction of allele frequency changes, (ii) reveals the reasons for these changes, (iii) is as general as natural selection, and (iv) provides a universal design principle for evolution. In this paper we evaluate these claims, and show that all of them are unfounded. If the objective is to analyze whether mutations that modify social behavior are favored or opposed by natural selection, then no aspect of inclusive fitness theory is needed.}, } @article {pmid24272207, year = {2014}, author = {Wikberg, EC and Ting, N and Sicotte, P}, title = {Kinship and similarity in residency status structure female social networks in black-and-white colobus monkeys (Colobus vellerosus).}, journal = {American journal of physical anthropology}, volume = {153}, number = {3}, pages = {365-376}, doi = {10.1002/ajpa.22435}, pmid = {24272207}, issn = {1096-8644}, mesh = {Aggression ; Animals ; Behavior, Animal/*physiology ; Colobus/*physiology ; Female ; Ghana ; Grooming ; Male ; *Social Behavior ; Social Dominance ; }, abstract = {Kinship shapes female social networks in many primate populations in which females remain in their natal group to breed. In contrast, it is unclear to which extent kinship affects the social networks in populations with female dispersal. Female Colobus vellerosus show routine facultative dispersal (i.e., some females remain philopatric and others disperse). This dispersal pattern allowed us to evaluate if facultative dispersed females form social networks shaped by an attraction to kin, to social partners with a high resource holding potential, or to similar social partners in terms of maturational stage, dominance rank, and residency status. During 2008 and 2009, we collected behavioral data via focal and ad libitum sampling of 61 females residing in eight groups at Boabeng-Fiema, Ghana. We determined kinship based on partial pedigrees and genotypes at 17 short tandem repeat loci. Kinship influenced coalition and affiliation networks in three groups consisting of long-term resident females with access to a relatively high number of female kin. In contrast, similar residency status was more important than kinship in structuring the affiliation network in one of two groups that contained recent female immigrants. In populations with female dispersal, the occurrence of kin structured social networks may not only depend on the kin composition of groups but also on how long the female kin have resided together. We found no consistent support for females biasing affiliation toward partners with high resource holding potential, possibly due to low levels of contest competition and small inter-individual differences in resource holding potential.}, } @article {pmid24268409, year = {2013}, author = {Ross, L and Gardner, A and Hardy, N and West, SA}, title = {Ecology, not the genetics of sex determination, determines who helps in eusocial populations.}, journal = {Current biology : CB}, volume = {23}, number = {23}, pages = {2383-2387}, doi = {10.1016/j.cub.2013.10.013}, pmid = {24268409}, issn = {1879-0445}, mesh = {Animals ; Biological Evolution ; Crustacea ; Female ; *Gender Identity ; *Gene-Environment Interaction ; Hymenoptera ; Male ; Models, Biological ; Mole Rats ; *Selection, Genetic ; Sex Determination Processes/*genetics ; Sex Factors ; *Sex Ratio ; *Social Behavior ; *Social Environment ; Spiders ; }, abstract = {In eusocial species, the sex ratio of helpers varies from female only, in taxa such as the social Hymenoptera (ants, bees, and wasps) [1], to an unbiased mixture of males and females, as in most termites [2]. Hamilton suggested that this difference owes to the haplodiploid genetics of the Hymenoptera leading to females being relatively more related to their siblings [3]. However, it has been argued that Hamilton's hypothesis does not work [4-9] and that the sex of helpers could instead be explained by variation in the ecological factors that favor eusociality [10]. Here we test these two competing hypotheses, which focus on the possible importance of different terms in Hamilton's rule [2, 11], with a comparative study across all sexual eusocial taxa. We find that the sex ratio of helpers (1) shows no significant correlation with whether species are haplodiploid or diploid and (2) shows a strong correlation with the ecological factor that had favored eusociality. Specifically, when the role of helpers is to defend the nest, both males and females help, whereas when the role of helpers is to provide brood care, then helpers are the sex or sexes that provided parental care ancestrally. More generally, our results confirm the ability of kin selection theory to explain the biology of eusocial species, independently of ploidy, and add support to the idea that haplodiploidy has been more important for shaping conflicts within eusocial societies than for explaining its origins [6, 12-19].}, } @article {pmid24237705, year = {2014}, author = {Muralidhar, P and de Sá, FP and Haddad, CF and Zamudio, KR}, title = {Kin-bias, breeding site selection and female fitness in a cannibalistic Neotropical frog.}, journal = {Molecular ecology}, volume = {23}, number = {2}, pages = {453-463}, doi = {10.1111/mec.12592}, pmid = {24237705}, issn = {1365-294X}, mesh = {Animals ; Anura/*genetics/*physiology ; Brazil ; Breeding ; Cannibalism ; Female ; Genotype ; Larva ; Likelihood Functions ; Male ; Microsatellite Repeats ; *Reproduction ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; *Territoriality ; }, abstract = {Resource availability influences sexual selection within populations and determines whether behaviours such as territoriality or resource sharing are adaptive. In Thoropa taophora, a frog endemic to the Atlantic Coastal Rainforest of Brazil, males compete for and defend limited breeding sites while females often share breeding sites with other females; however, sharing breeding sites may involve costs due to cannibalism by conspecific tadpoles. We studied a breeding population of T. taophora to determine (i) whether this species exhibits polygynous mating involving female choice for territorial males and limited breeding resources; (ii) whether limited breeding resources create the potential for male-male cooperation in defence of neighbouring territories; and (iii) whether females sharing breeding sites exhibit kin-biased breeding site choice, possibly driven by fitness losses due to cannibalism among offspring of females sharing sites. We used microsatellites to reconstruct parentage and quantify relatedness at eight breeding sites in our focal population, where these sites are scarce, and in a second population, where sites are abundant. We found that at localities where the appropriate sites for reproduction are spatially limited, the mating system for this species is polygynous, with typically two females sharing a breeding site with a male. We also found that females exhibit negative kin-bias in their choice of breeding sites, potentially to maximize their inclusive fitness by avoiding tadpole cannibalism of highly related kin. Our results indicate that male territorial defence and female site sharing are likely important components of this mating system, and we propose that kinship-dependent avoidance in mating strategies may be more general than previously realized.}, } @article {pmid24228918, year = {2013}, author = {Goldsmith, TC}, title = {Arguments against non-programmed aging theories.}, journal = {Biochemistry. Biokhimiia}, volume = {78}, number = {9}, pages = {971-978}, doi = {10.1134/S0006297913090022}, pmid = {24228918}, issn = {1608-3040}, mesh = {Aging/genetics/*physiology ; Animals ; Biological Evolution ; Humans ; Longevity/genetics/physiology ; Species Specificity ; }, abstract = {Until recently, non-programmed theories of biological aging were popular because of the widespread perception that the evolution process could not support the development and retention of programmed aging in mammals. However, newer evolutionary mechanics theories including group selection, kin selection, and evolvability theory support mammal programmed aging, and multiple programmed aging theories have been published based on the new mechanics. Some proponents of non-programmed aging still contend that their non-programmed theories are superior despite the new mechanics concepts. However, as summarized here, programmed theories provide a vastly better fit to empirical evidence and do not suffer from multiple implausible assumptions that are required by non-programmed theories. This issue is important because programmed theories suggest very different mechanisms for the aging process and therefore different mechanisms behind highly age-related diseases and conditions such as cancer, heart disease, and stroke.}, } @article {pmid24225452, year = {2014}, author = {Pfefferle, D and Ruiz-Lambides, AV and Widdig, A}, title = {Female rhesus macaques discriminate unfamiliar paternal sisters in playback experiments: support for acoustic phenotype matching.}, journal = {Proceedings. Biological sciences}, volume = {281}, number = {1774}, pages = {20131628}, pmid = {24225452}, issn = {1471-2954}, support = {P40 OD012217/OD/NIH HHS/United States ; 8P40OD012217/OD/NIH HHS/United States ; }, mesh = {Acoustic Stimulation ; Animals ; Cues ; Female ; Macaca mulatta/genetics/physiology/*psychology ; Phenotype ; Recognition, Psychology ; *Vocalization, Animal ; }, abstract = {Widespread evidence exists that when relatives live together, kinship plays a central role in shaping the evolution of social behaviour. Previous studies showed that female rhesus macaques (Macaca mulatta) recognize familiar maternal kin using vocal cues. Recognizing paternal kin might, however, be more difficult as rhesus females mate promiscuously during the possible conception period, most probably concealing paternity. Behavioural observations indicate that semi free-ranging female rhesus macaques prefer to associate with their paternal half-sisters in comparison to unrelated females within the same group, particularly when born within the same age cohort. However, the cues and mechanism/s used in paternal kin discrimination remain under debate. Here, we investigated whether female rhesus macaques use the acoustic modality to discriminate between paternal half-sisters and non-kin, and tested familiarity and phenotype matching as the underlying mechanisms. We found that test females responded more often to calls of paternal half-sisters compared with calls of unrelated females, and that this discrimination ability was independent of the level of familiarity between callers and test females, which provides, to our knowledge, the first evidence for acoustic phenotype matching. Our study strengthens the evidence that female rhesus macaques can recognize their paternal kin, and that vocalizations are used as a cue.}, } @article {pmid24215887, year = {2014}, author = {Iritani, R and Iwasa, Y}, title = {Parasite infection drives the evolution of state-dependent dispersal of the host.}, journal = {Theoretical population biology}, volume = {92}, number = {}, pages = {1-13}, doi = {10.1016/j.tpb.2013.10.005}, pmid = {24215887}, issn = {1096-0325}, mesh = {Animals ; *Biological Evolution ; *Host-Parasite Interactions ; *Models, Biological ; Virulence ; }, abstract = {Dispersal plays a fundamental role in shaping the ecological processes such as host-parasite interactions, and the understanding of host dispersal tendency leads to that of parasites. Here, we present the result of our study on how the evolutionarily stable dispersal of a host would depend on parasite infection, considering kin competition among neighbours. We show that the evolving dispersal rate might be higher for susceptible than for infected individuals (S-biased dispersal) or vice versa (I-biased dispersal). S-biased dispersal is favoured by strong virulence affecting competitive ability, by high rate of parasite release during dispersal, and by low virulence for infected emigrants (i.e. low virulence affecting dispersal ability), whereas I-biased dispersal is favoured in the opposite situation. We also discuss population structure or between-deme genetic differentiation of the host measured with Wright's FST. In I-biased dispersal, between-deme genetic differentiation decreases with the infection rate, while in S-biased dispersal, genetic differentiation increases with infection rate.}, } @article {pmid24211682, year = {2014}, author = {Lotem, A and Biran-Yoeli, I}, title = {Evolution of learning and levels of selection: a lesson from avian parent-offspring communication.}, journal = {Theoretical population biology}, volume = {91}, number = {}, pages = {58-74}, doi = {10.1016/j.tpb.2013.10.003}, pmid = {24211682}, issn = {1096-0325}, mesh = {*Animal Communication ; Animals ; *Biological Evolution ; Birds/*physiology ; *Learning ; }, abstract = {In recent years, it has become increasingly clear that the evolution of behavior may be better understood as the evolution of the learning mechanisms that produce it, and that such mechanisms should be modeled and tested explicitly. However, this approach, which has recently been applied to animal foraging and decision-making, has rarely been applied to the social and communicative behaviors that are likely to operate in complex social environments and be subject to multi-level selection. Here we use genetic, agent-based evolutionary simulations to explore how learning mechanisms may evolve to adjust the level of nestling begging (offspring signaling of need), and to examine the possible consequences of this process for parent-offspring conflict and communication. In doing so, we also provide the first step-by-step dynamic model of parent-offspring communication. The results confirm several previous theoretical predictions and demonstrate three novel phenomena. First, negatively frequency-dependent group-level selection can generate a stable polymorphism of learning strategies and parental responses. Second, while conventional reinforcement learning models fail to cope successfully with family dynamics at the nest, a newly developed learning model (incorporating behaviors that are consistent with recent experimental results on learning in nestling begging) produced effective learning, which evolved successfully. Third, while kin-selection affects the frequency of the different learning genes, its impact on begging slope and intensity was unexpectedly negligible, demonstrating that evolution is a complex process, and showing that the effect of kin-selection on behaviors that are shaped by learning may not be predicted by simple application of Hamilton's rule.}, } @article {pmid24171718, year = {2014}, author = {Smith, J and Van Dyken, JD and Velicer, GJ}, title = {Nonadaptive processes can create the appearance of facultative cheating in microbes.}, journal = {Evolution; international journal of organic evolution}, volume = {68}, number = {3}, pages = {816-826}, doi = {10.1111/evo.12306}, pmid = {24171718}, issn = {1558-5646}, support = {R01 GM07690/GM/NIGMS NIH HHS/United States ; }, mesh = {Adaptation, Physiological/*genetics ; *Evolution, Molecular ; *Models, Genetic ; Mutation ; Myxococcus/*genetics/physiology ; Selection, Genetic ; Spores, Bacterial/genetics ; }, abstract = {Adaptations to social life may take the form of facultative cheating, in which organisms cooperate with genetically similar individuals but exploit others. Consistent with this possibility, many strains of social microbes like Myxococcus bacteria and Dictyostelium amoebae have equal fitness in single-genotype social groups but outcompete other strains in mixed-genotype groups. Here we show that these observations are also consistent with an alternative, nonadaptive scenario: kin selection-mutation balance under local competition. Using simple mathematical models, we show that deleterious mutations that reduce competitiveness within social groups (growth rate, e.g.) without affecting group productivity can create fitness effects that are only expressed in the presence of other strains. In Myxococcus, mutations that delay sporulation may strongly reduce developmental competitiveness. Deleterious mutations are expected to accumulate when high levels of kin selection relatedness relax selection within groups. Interestingly, local resource competition can create nonzero "cost" and "benefit" terms in Hamilton's rule even in the absence of any cooperative trait. Our results show how deleterious mutations can play a significant role even in organisms with large populations and highlight the need to test evolutionary causes of social competition among microbes.}, } @article {pmid24169647, year = {2014}, author = {Alemu, SW and Berg, P and Janss, L and Bijma, P}, title = {Indirect genetic effects and kin recognition: estimating IGEs when interactions differ between kin and strangers.}, journal = {Heredity}, volume = {112}, number = {2}, pages = {197-206}, pmid = {24169647}, issn = {1365-2540}, mesh = {Algorithms ; Breeding ; Computer Simulation ; Genetic Variation ; Humans ; *Models, Genetic ; Monte Carlo Method ; Phenotype ; *Quantitative Trait, Heritable ; Reproducibility of Results ; }, abstract = {Social interactions among individuals are widespread, both in natural and domestic populations. As a result, trait values of individuals may be affected by genes in other individuals, a phenomenon known as indirect genetic effects (IGEs). IGEs can be estimated using linear mixed models. The traditional IGE model assumes that an individual interacts equally with all its partners, whether kin or strangers. There is abundant evidence, however, that individuals behave differently towards kin as compared with strangers, which agrees with predictions from kin-selection theory. With a mix of kin and strangers, therefore, IGEs estimated from a traditional model may be incorrect, and selection based on those estimates will be suboptimal. Here we investigate whether genetic parameters for IGEs are statistically identifiable in group-structured populations when IGEs differ between kin and strangers, and develop models to estimate such parameters. First, we extend the definition of total breeding value and total heritable variance to cases where IGEs depend on relatedness. Next, we show that the full set of genetic parameters is not identifiable when IGEs differ between kin and strangers. Subsequently, we present a reduced model that yields estimates of the total heritable effects on kin, on non-kin and on all social partners of an individual, as well as the total heritable variance for response to selection. Finally we discuss the consequences of analysing data in which IGEs depend on relatedness using a traditional IGE model, and investigate group structures that may allow estimation of the full set of genetic parameters when IGEs depend on kin.}, } @article {pmid24167305, year = {2013}, author = {Young, AJ and Bennett, NC}, title = {Intra-sexual selection in cooperative mammals and birds: why are females not bigger and better armed?.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {368}, number = {1631}, pages = {20130075}, pmid = {24167305}, issn = {1471-2970}, support = {BB/H022716/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; *Cooperative Behavior ; Desert Climate ; Female ; Male ; Mole Rats/anatomy & histology/genetics/*physiology ; Reproduction/genetics/*physiology ; Selection, Genetic/genetics/*physiology ; Sex Characteristics ; *Social Dominance ; }, abstract = {In cooperatively breeding mammals and birds, intra-sexual reproductive competition among females may often render variance in reproductive success higher among females than males, leading to the prediction that intra-sexual selection in such species may have yielded the differential exaggeration of competitive traits among females. However, evidence to date suggests that female-biased reproductive variance in such species is rarely accompanied by female-biased sexual dimorphisms. We illustrate the problem with data from wild Damaraland mole-rat, Fukomys damarensis, societies: the variance in lifetime reproductive success among females appears to be higher than that among males, yet males grow faster, are much heavier as adults and sport larger skulls and incisors (the weapons used for fighting) for their body lengths than females, suggesting that intra-sexual selection has nevertheless acted more strongly on the competitive traits of males. We then consider potentially general mechanisms that could explain these disparities by tempering the relative intensity of selection for competitive trait exaggeration among females in cooperative breeders. Key among these may be interactions with kin selection that could nevertheless render the variance in inclusive fitness lower among females than males, and fundamental aspects of the reproductive biology of females that may leave reproductive conflict among females more readily resolved without overt physical contests.}, } @article {pmid24167148, year = {2014}, author = {Cooper, LC and Desjonqueres, C and Leather, SR}, title = {Cannibalism in the pea aphid, Acyrthosiphon pisum.}, journal = {Insect science}, volume = {21}, number = {6}, pages = {750-758}, doi = {10.1111/1744-7917.12070}, pmid = {24167148}, issn = {1744-7917}, mesh = {Animals ; Aphids/genetics/*physiology ; *Cannibalism ; Life Cycle Stages ; Peas/parasitology/physiology ; *Starvation ; }, abstract = {Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such behaviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vica faba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F = 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or duration of cannibalistic activities within and between different clones (P ≥ 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018).}, } @article {pmid24166925, year = {2013}, author = {Mace, R}, title = {Cooperation and conflict between women in the family.}, journal = {Evolutionary anthropology}, volume = {22}, number = {5}, pages = {251-258}, doi = {10.1002/evan.21374}, pmid = {24166925}, issn = {1520-6505}, mesh = {Conflict, Psychological ; *Cooperative Behavior ; *Family Characteristics ; Female ; Humans ; Male ; Reproduction ; *Social Behavior ; *Women ; }, abstract = {Here I review recent research on reproductive conflict between females in families and how it influences their reproductive behaviour. Kin selection can favor cooperation between parent and offspring, siblings, or unrelated co-residents who share interests in other family members such as grand-offspring. However, these are also the individuals most likely to be sharing resources, and so conflict can also emerge. While substantial interest has arisen in evolutionary anthropology, especially over the last two decades, in the possibility of cooperative breeding in humans, less attention has been paid to reproductive conflict among female kin. Communal breeding in animals is generally understood as emerging from competition over the resources needed to breed. Competition for household resources is a problem that also faces human families. Models suggest that in some circumstances, inclusive fitness can be maximized by sharing reproduction rather than harming relatives by fighting with them, even if the shares that emerge are not equal. Thus, competition and cooperation turn out to be strongly related to each other. Reproductive competition within and between families may have underpinned the biological evolution of fertility patterns (such as menopause) and the cultural evolution of marriage, residence, and inheritance norms (such as late male marriage or primogeniture), which can enhance cooperation and minimize the observed incidence of such conflicts.}, } @article {pmid24166924, year = {2013}, author = {Widdig, A}, title = {The Impact of male reproductive skew on kin structure and sociality in multi-male groups.}, journal = {Evolutionary anthropology}, volume = {22}, number = {5}, pages = {239-250}, doi = {10.1002/evan.21366}, pmid = {24166924}, issn = {1520-6505}, mesh = {Animals ; Breeding ; Cercopithecinae ; Female ; Male ; *Reproduction ; *Sexual Behavior, Animal ; Siblings ; *Social Behavior ; }, abstract = {Patterns of within-group relatedness are expected to affect the prospects for cooperation among group members through kin selection. It has long been established that dispersal patterns determine the availability of kin and there is ample evidence of matrilineal kin biases in social behavior across primate species. However, in 1979, Jeanne Altmann(1) suggested that mating patterns also influence the structure of within-group relatedness; high male reproductive skew and the frequent replacement of breeding males leads to relatively high levels of paternal relatedness and age-structured paternal sibships within groups. As a consequence of frequent replacement of breeding males, relatedness among offspring of a given female will be reduced to the half- rather than full-sibling level. Depending on the number of sires and degree of relatedness among mothers, members of the same birth cohort may be as closely related as maternal siblings. If animals are able to recognize their paternal kin and exhibit biases in favor of them, this may influence the distribution of cooperation and the intensity of competition within groups of primates. Here, I summarize the evidence that serves as the basis for Altmann's predictions and review evidence regarding whether or not the availability of paternal kin also leads to paternal kin bias among primates.}, } @article {pmid24152004, year = {2013}, author = {McLeod, DV and Wild, G}, title = {Ecological constraints influence the emergence of cooperative breeding when population dynamics determine the fitness of helpers.}, journal = {Evolution; international journal of organic evolution}, volume = {67}, number = {11}, pages = {3221-3232}, doi = {10.1111/evo.12188}, pmid = {24152004}, issn = {1558-5646}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; Genetic Fitness ; Models, Biological ; Population Density ; Reproduction ; }, abstract = {Cooperative breeding is a system in which certain individuals facilitate the production of offspring by others. The ecological constraints hypothesis states that ecological conditions deter individuals from breeding independently, and so individuals breed cooperatively to make the best of a bad situation. Current theoretical support for the ecological constraints hypothesis is lacking. We formulate a mathematical model that emphasizes the underlying ecology of cooperative breeders. Our goal is to derive theoretical support for the ecological constraints hypothesis using an ecological model of population dynamics. We consider a population composed of two kinds of individuals, nonbreeders (auxiliaries) and breeders. We suppose that help provided by an auxiliary increases breeder fecundity, but reduces the probability with which the auxiliary becomes a breeder. Our main result is a condition that guarantees success of auxiliary help. We predict that increasing the cost of dispersal promotes helping, in agreement with verbal theory. We also predict that increasing breeder mortality can either hinder helping (at high population densities), or promote it (at low population densities). We conclude that ecological constraints can exert influence over the evolution of auxiliary help when population dynamics are considered; moreover, that influence need not coincide with direct fitness benefits as previously found.}, } @article {pmid24132311, year = {2013}, author = {Riehl, C}, title = {Evolutionary routes to non-kin cooperative breeding in birds.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1772}, pages = {20132245}, pmid = {24132311}, issn = {1471-2954}, mesh = {Animal Distribution ; Animals ; *Biological Evolution ; Birds/genetics/*physiology ; *Nesting Behavior ; Selection, Genetic ; *Social Behavior ; }, abstract = {Cooperatively breeding animals live in social groups in which some individuals help to raise the offspring of others, often at the expense of their own reproduction. Kin selection--when individuals increase their inclusive fitness by aiding genetic relatives--is a powerful explanation for the evolution of cooperative breeding, particularly because most groups consist of family members. However, recent molecular studies have revealed that many cooperative groups also contain unrelated immigrants, and the processes responsible for the formation and maintenance of non-kin coalitions are receiving increasing attention. Here, I provide the first systematic review of group structure for all 213 species of cooperatively breeding birds for which data are available. Although the majority of species (55%) nest in nuclear family groups, cooperative breeding by unrelated individuals is more common than previously recognized: 30% nest in mixed groups of relatives and non-relatives, and 15% nest primarily with non-relatives. Obligate cooperative breeders are far more likely to breed with non-kin than are facultative cooperators, indicating that when constraints on independent breeding are sufficiently severe, the direct benefits of group membership can substitute for potential kin-selected benefits. I review three patterns of dispersal that give rise to social groups with low genetic relatedness, and I discuss the selective pressures that favour the formation of such groups. Although kin selection has undoubtedly been crucial to the origin of most avian social systems, direct benefits have subsequently come to play a predominant role in some societies, allowing cooperation to persist despite low genetic relatedness.}, } @article {pmid24132100, year = {2013}, author = {Herbers, JM}, title = {50 Years on: the legacy of William Donald Hamilton.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130792}, pmid = {24132100}, issn = {1744-957X}, mesh = {Animals ; Biological Evolution ; Biology/*history ; *Genetic Fitness ; History, 20th Century ; Humans ; }, } @article {pmid24132096, year = {2013}, author = {Tsuji, K}, title = {Kin selection, species richness and community.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130491}, pmid = {24132096}, issn = {1744-957X}, mesh = {Animals ; Ants/*physiology ; Behavior, Animal ; Biological Evolution ; Competitive Behavior ; Ecology ; Female ; *Genetic Fitness ; Insecta ; Male ; Population Dynamics ; Reproduction ; Selection, Genetic ; Sexual Behavior, Animal ; Social Behavior ; *Species Specificity ; }, abstract = {Can evolutionary and ecological dynamics operating at one level of the biological hierarchy affect the dynamics and structure at other levels? In social insects, strong hostility towards unrelated individuals can evolve as a kin-selected counter-adaptation to intraspecific social parasitism. This aggression in turn might cause intraspecific competition to predominate over interspecific competition, permitting coexistence with other social insect species. In other words, kin selection-a form of intra-population dynamics-might enhance the species richness of the community, a higher-level structure. The converse effect, from higher to lower levels, might also operate, whereby strong interspecific competition may limit the evolution of selfish individual traits. If the latter effect were to prove more important, it would challenge the common view that intra-population dynamics (via individual or gene selection) is the main driver of evolution.}, } @article {pmid24132095, year = {2013}, author = {Kamel, SJ and Grosberg, RK}, title = {Kinship and the evolution of social behaviours in the sea.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130454}, pmid = {24132095}, issn = {1744-957X}, mesh = {Animals ; Biological Evolution ; Clutch Size/physiology ; Ecology ; Ecosystem ; Female ; Invertebrates/anatomy & histology/*physiology ; Life Cycle Stages/physiology ; Male ; Marine Biology ; Models, Biological ; Oceans and Seas ; Population Dynamics ; *Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {Until recently, little attention has been paid to the existence of kin structure in the sea, despite the fact that many marine organisms are sessile or sedentary. This lack of attention to kin structure, and its impacts on social evolution, historically stems from the pervasive assumption that the dispersal of gametes and larvae is almost always sufficient to prevent any persistent associations of closely related offspring or adults. However, growing evidence, both theoretical and empirical, casts doubt on the generality of this assumption, not only in species with limited dispersal, but also in species with long dispersive phases. Moreover, many marine organisms either internally brood their progeny or package them in nurseries, both of which provide ample opportunities for kinship to influence the nature and outcomes of social interactions among family members. As the evidence for kin structure within marine populations mounts, it follows that kin selection may play a far greater role in the evolution of both behaviours and life histories of marine organisms than is presently appreciated.}, } @article {pmid24132094, year = {2013}, author = {Boomsma, JJ and d'Ettorre, P}, title = {Nice to kin and nasty to non-kin: revisiting Hamilton's early insights on eusociality.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130444}, pmid = {24132094}, issn = {1744-957X}, mesh = {Altruism ; Animals ; Ants ; *Behavior, Animal ; Biological Evolution ; Breeding ; Genetic Fitness ; Genetic Variation ; Humans ; Insecta ; Male ; Models, Genetic ; Selection, Genetic ; *Social Behavior ; }, abstract = {When helping behaviour is costly, Hamiltonian logic implies that animals need to direct helpful acts towards kin, so that indirect fitness benefits justify the costs. We revisit inferences about nepotism and aggression in Hamilton's 1964 paper to argue that he overestimated the general significance of nepotism, but that other issues that he raised continue to suggest novel research agendas today. We now know that nepotism in eusocial insects is rare, because variation in genetic recognition cues is insufficient. A lower proportion of individuals breeding and larger clutch sizes selecting for a more uniform colony odour may explain this. Irreversible worker sterility can induce both the fiercest possible aggression and the highest likelihood of helping random distant kin, but these Hamiltonian contentions still await large-scale testing in social animals.}, } @article {pmid24132093, year = {2013}, author = {Tsutsui, ND}, title = {Dissecting ant recognition systems in the age of genomics.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130416}, pmid = {24132093}, issn = {1744-957X}, mesh = {Animals ; Ants/*physiology ; *Biological Evolution ; Cues ; Female ; Genomics ; Hydrocarbons/chemistry ; Insect Proteins/*genetics ; Male ; Perception ; Phenotype ; *Recognition, Psychology ; Reproduction/*physiology ; Sex Attractants/*genetics ; *Sexual Behavior, Animal ; Signal Transduction ; Social Behavior ; }, abstract = {Hamilton is probably best known for his seminal work demonstrating the role of kin selection in social evolution. His work made it clear that, for individuals to direct their altruistic behaviours towards appropriate recipients (kin), mechanisms must exist for kin recognition. In the social insects, colonies are typically comprised of kin, and colony recognition cues are used as proxies for kinship cues. Recent years have brought rapid advances in our understanding of the genetic and molecular mechanisms that are used for this process. Here, I review some of the most notable advances, particularly the contributions from recent ant genome sequences and molecular biology.}, } @article {pmid24132092, year = {2013}, author = {Thompson, GJ and Hurd, PL and Crespi, BJ}, title = {Genes underlying altruism.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130395}, pmid = {24132092}, issn = {1744-957X}, mesh = {Alleles ; *Altruism ; Animals ; Behavior, Animal ; Biological Evolution ; *Genetic Fitness ; Hierarchy, Social ; Humans ; Insecta/*genetics ; Models, Genetic ; Oxytocin/metabolism ; Phenotype ; Polymorphism, Genetic ; Selection, Genetic ; *Social Behavior ; }, abstract = {William D. Hamilton postulated the existence of 'genes underlying altruism', under the rubric of inclusive fitness theory, a half-century ago. Such genes are now poised for discovery. In this article, we develop a set of intuitive criteria for the recognition and analysis of genes for altruism and describe the first candidate genes affecting altruism from social insects and humans. We also provide evidence from a human population for genetically based trade-offs, underlain by oxytocin-system polymorphisms, between alleles for altruism and alleles for non-social cognition. Such trade-offs between self-oriented and altruistic behaviour may influence the evolution of phenotypic diversity across all social animals.}, } @article {pmid24132089, year = {2013}, author = {Costa, JT}, title = {Hamiltonian inclusive fitness: a fitter fitness concept.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130335}, pmid = {24132089}, issn = {1744-957X}, mesh = {Altruism ; Animals ; Biological Evolution ; Biology/*history ; *Genetic Fitness ; Genomic Imprinting ; History, 19th Century ; History, 20th Century ; Humans ; Insecta ; *Models, Biological ; Selection, Genetic ; Social Behavior ; }, abstract = {In 1963-1964 W. D. Hamilton introduced the concept of inclusive fitness, the only significant elaboration of Darwinian fitness since the nineteenth century. I discuss the origin of the modern fitness concept, providing context for Hamilton's discovery of inclusive fitness in relation to the puzzle of altruism. While fitness conceptually originates with Darwin, the term itself stems from Spencer and crystallized quantitatively in the early twentieth century. Hamiltonian inclusive fitness, with Price's reformulation, provided the solution to Darwin's 'special difficulty'-the evolution of caste polymorphism and sterility in social insects. Hamilton further explored the roles of inclusive fitness and reciprocation to tackle Darwin's other difficulty, the evolution of human altruism. The heuristically powerful inclusive fitness concept ramified over the past 50 years: the number and diversity of 'offspring ideas' that it has engendered render it a fitter fitness concept, one that Darwin would have appreciated.}, } @article {pmid24132088, year = {2013}, author = {Wenseleers, T and Helanterä, H and Alves, DA and Dueñez-Guzmán, E and Pamilo, P}, title = {Towards greater realism in inclusive fitness models: the case of worker reproduction in insect societies.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130334}, pmid = {24132088}, issn = {1744-957X}, mesh = {Animals ; Bees ; *Behavior, Animal ; Biological Evolution ; Female ; *Genetic Fitness ; Hierarchy, Social ; Insecta ; Male ; Models, Genetic ; Reproduction/genetics ; Sex Factors ; Sex Ratio ; Sexual Behavior, Animal ; Social Behavior ; }, abstract = {The conflicts over sex allocation and male production in insect societies have long served as an important test bed for Hamilton's theory of inclusive fitness, but have for the most part been considered separately. Here, we develop new coevolutionary models to examine the interaction between these two conflicts and demonstrate that sex ratio and colony productivity costs of worker reproduction can lead to vastly different outcomes even in species that show no variation in their relatedness structure. Empirical data on worker-produced males in eight species of Melipona bees support the predictions from a model that takes into account the demographic details of colony growth and reproduction. Overall, these models contribute significantly to explaining behavioural variation that previous theories could not account for.}, } @article {pmid24132087, year = {2013}, author = {Hall, DW and Yi, SV and Goodisman, MA}, title = {Kin selection, genomics and caste-antagonistic pleiotropy.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130309}, pmid = {24132087}, issn = {1744-957X}, mesh = {Animals ; Ants ; Bees ; Biological Evolution ; Evolution, Molecular ; Genetic Variation ; Genome ; Genomics ; Genotype ; Insecta ; Models, Genetic ; Phenotype ; Polymorphism, Genetic ; Reproduction/*genetics ; Sexual Behavior, Animal ; *Social Behavior ; Wasps ; }, abstract = {Kin selection is a fundamentally important process that affects the evolution of social behaviours. The genomics revolution now provides the opportunity to test kin selection theory using genomic data. In this commentary, we discuss previous studies that explored the link between kin selection and patterns of variation within the genome. We then present a new theory aimed at understanding the evolution of genes involved in the development of social insects. Specifically, we investigate caste-antagonistic pleiotropy, which occurs when the phenotypes of distinct castes are optimized by different genotypes at a single locus. We find that caste-antagonistic pleiotropy leads to narrow regions where polymorphism can be maintained. Furthermore, multiple mating by queens reduces the region in which worker-favoured alleles fix, which suggests that multiple mating impedes worker caste evolution. We conclude by discussing ways to test these and other facets of kin selection using newly emerging genomic data.}, } @article {pmid24132086, year = {2013}, author = {Haig, D}, title = {Imprinted green beards: a little less than kin and more than kind.}, journal = {Biology letters}, volume = {9}, number = {6}, pages = {20130199}, pmid = {24132086}, issn = {1744-957X}, mesh = {Algorithms ; *Alleles ; Animals ; DNA/*chemistry ; *Genomic Imprinting ; Humans ; Models, Genetic ; Multigene Family ; Mutation ; Probability ; RNA/*chemistry ; RNA, Small Interfering/metabolism ; }, abstract = {RNA is complementary to the DNA sequence from which it is transcribed. Therefore, interactions between DNA and RNA provide a simple mechanism of genetic self-detection within nuclei. Imprinted RNAs could enable alleles of maternal and paternal origin to detect whether they are the same (homozygous) or different (heterozygous), and thereby provide strategic information about expected relatedness to siblings.}, } @article {pmid24118386, year = {2013}, author = {Łukasik, P and Guo, H and van Asch, M and Ferrari, J and Godfray, HC}, title = {Protection against a fungal pathogen conferred by the aphid facultative endosymbionts Rickettsia and Spiroplasma is expressed in multiple host genotypes and species and is not influenced by co-infection with another symbiont.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {12}, pages = {2654-2661}, doi = {10.1111/jeb.12260}, pmid = {24118386}, issn = {1420-9101}, support = {BB/E010857/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Aphids/genetics/*microbiology ; Fungi/*pathogenicity ; Genotype ; *Host-Pathogen Interactions ; Rickettsia/*pathogenicity ; Spiroplasma/*pathogenicity ; *Symbiosis ; }, abstract = {Many insects harbour facultative endosymbiotic bacteria, often more than one type at a time. These symbionts can have major effects on their hosts' biology, which may be modulated by the presence of other symbiont species and by the host's genetic background. We investigated these effects by transferring two sets of facultative endosymbionts (one Hamiltonella and Rickettsia, the other Hamiltonella and Spiroplasma) from naturally double-infected pea aphid hosts into five novel host genotypes of two aphid species. The symbionts were transferred either together or separately. We then measured aphid fecundity and susceptibility to an entomopathogenic fungus. The pathogen-protective phenotype conferred by the symbionts Rickettsia and Spiroplasma varied among host genotypes, but was not influenced by co-infection with Hamiltonella. Fecundity varied across single and double infections and between symbiont types, aphid genotypes and species. Some host genotypes benefit from harbouring more than one symbiont type.}, } @article {pmid24118371, year = {2013}, author = {Taylor, TB and Rodrigues, AM and Gardner, A and Buckling, A}, title = {The social evolution of dispersal with public goods cooperation.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {12}, pages = {2644-2653}, doi = {10.1111/jeb.12259}, pmid = {24118371}, issn = {1420-9101}, mesh = {*Biological Evolution ; *Cooperative Behavior ; Humans ; *Social Behavior ; }, abstract = {Selection can favour the evolution of individually costly dispersal if this alleviates competition between relatives. However, conditions that favour altruistic dispersal also mediate selection for other social behaviours, such as public goods cooperation, which in turn is likely to mediate dispersal evolution. Here, we investigate - both experimentally (using bacteria) and theoretically - how social habitat heterogeneity (i.e. the distribution of public goods cooperators and cheats) affects the evolution of dispersal. In addition to recovering the well-known theoretical result that the optimal level of dispersal increases with genetic relatedness of patch mates, we find both mathematically and experimentally that dispersal is always favoured when average patch occupancy is low, but when average patch occupancy is high, the presence of public goods cheats greatly alters selection for dispersal. Specifically, when public goods cheats are localized to the home patch, higher dispersal rates are favoured, but when cheats are present throughout available patches, lower dispersal rates are favoured. These results highlight the importance of other social traits in driving dispersal evolution.}, } @article {pmid24118247, year = {2013}, author = {Krupp, DB}, title = {How to distinguish altruism from spite (and why we should bother).}, journal = {Journal of evolutionary biology}, volume = {26}, number = {12}, pages = {2746-2749}, doi = {10.1111/jeb.12253}, pmid = {24118247}, issn = {1420-9101}, mesh = {*Altruism ; Humans ; *Social Behavior ; }, abstract = {Social behaviour is often described as altruistic, spiteful, selfish or mutually beneficial. These terms are appealing, but it has not always been clear how they are defined and what purpose they serve. Here, I show that the distinctions among them arise from the ways in which fitness is partitioned: none can be drawn when the fitness consequences of an action are wholly aggregated, but they manifest clearly when the consequences are partitioned into primary and secondary (neighbourhood) effects. I argue that the primary interaction is the principal source of adaptive design, because (i) it is this interaction that determines the fit of an adaptation and (ii) it is the actor and primary recipients whom an adaptation foremost affects. The categories of social action are thus instrumental to any account of evolved function.}, } @article {pmid24100232, year = {2013}, author = {Amsalem, E and Shpigler, H and Bloch, G and Hefetz, A}, title = {Dufour's gland secretion, sterility and foraging behavior: correlated behavior traits in bumblebee workers.}, journal = {Journal of insect physiology}, volume = {59}, number = {12}, pages = {1250-1255}, doi = {10.1016/j.jinsphys.2013.09.007}, pmid = {24100232}, issn = {1879-1611}, mesh = {Animals ; Bees/*physiology ; *Behavior, Animal ; Bodily Secretions ; Esters/*metabolism ; Female ; Infertility ; }, abstract = {Bombus terrestris colonies go through two major phases: the "pre-competition phase" in which the queen is the sole reproducer and aggression is rare, and the "competition phase" in which workers aggressively compete over reproduction. Conflicts over reproduction are partially regulated by a group of octyl esters that are produced in Dufour's gland of reproductively subordinate workers and protect them from being aggressed. However, workers possess octyl esters even before overt aggression occurs, raising the question of why produce the ester-signal before it is functionally necessary? In most insect societies, foragers show reduced aggression and low dominance rank. We hypothesize that ester production in B. terrestris is not only correlated with sterility but also with foraging, signaling cooperative behavior by subordinate workers. Such a signal helps to maintain social organization, reduce the cost of fights between reproductives and helpers, and increase colony productivity, enabling subordinates to gain greater inclusive fitness. We demonstrate that foragers produce larger amounts of esters compared to non-foragers, and that their amounts positively correlate with foraging efforts. We further suggest that task performance, potential fecundity, and aggression are interlinked, and that worker-worker interactions are involved in regulating foraging behavior. B. terrestris, being an intermediate phase between primitive and derived eusocial insects, provides an excellent model for understanding the evolution of early phases of eusociality. Our results, combined with those in primitively eusocial wasps, suggest that at early stages of social evolution, reproduction was regulated by a "primordial division of labor", that comprised foragers and reproducers, which further evolved to a more complex division of labor, a hallmark of eusociality.}, } @article {pmid24094343, year = {2013}, author = {Tonsor, SJ and Elnaccash, TW and Scheiner, SM}, title = {Developmental instability is genetically correlated with phenotypic plasticity, constraining heritability, and fitness.}, journal = {Evolution; international journal of organic evolution}, volume = {67}, number = {10}, pages = {2923-2935}, doi = {10.1111/evo.12175}, pmid = {24094343}, issn = {1558-5646}, mesh = {Adaptation, Biological/genetics/*physiology ; Analysis of Variance ; Arabidopsis/genetics/*growth & development/metabolism ; *Biological Evolution ; *Environment ; Genetic Fitness/*genetics ; Genotype ; Nitrogen/metabolism ; *Phenotype ; }, abstract = {Although adaptive plasticity would seem always to be favored by selection, it occurs less often than expected. This lack of ubiquity suggests that there must be trade-offs, costs, or limitations associated with plasticity. Yet, few costs have been found. We explore one type of limitation, a correlation between plasticity and developmental instability, and use quantitative genetic theory to show why one should expect a genetic correlation. We test that hypothesis using the Landsberg erecta × Cape Verde Islands recombinant inbred lines (RILs) of Arabidopsis thaliana. RILs were grown at four different nitrogen (N) supply levels that span the range of N availabilities previously documented in North American field populations. We found a significant multivariate relationship between the cross-environment trait plasticity and the within-environment, within-RIL developmental instability across 13 traits. This genetic covariation between plasticity and developmental instability has two costs. First, theory predicts diminished fitness for highly plastic lines under stabilizing selection, because their developmental instability and variance around the optimum phenotype will be greater compared to nonplastic genotypes. Second, empirically the most plastic traits exhibited heritabilities reduced by 57% on average compared to nonplastic traits. This demonstration of potential costs in inclusive fitness and heritability provoke a rethinking of the evolutionary role of plasticity.}, } @article {pmid24091924, year = {2013}, author = {VanderLaan, DP and Ren, Z and Vasey, PL}, title = {Male androphilia in the ancestral environment. An ethnological analysis.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {24}, number = {4}, pages = {375-401}, pmid = {24091924}, issn = {1936-4776}, mesh = {*Altruism ; Family ; Homosexuality, Male/ethnology ; Humans ; Male ; Men/*psychology ; Sexual Behavior/*ethnology ; Transgender Persons/psychology ; }, abstract = {The kin selection hypothesis posits that male androphilia (male sexual attraction to adult males) evolved because androphilic males invest more in kin, thereby enhancing inclusive fitness. Increased kin-directed altruism has been repeatedly documented among a population of transgendered androphilic males, but never among androphilic males in other cultures who adopt gender identities as men. Thus, the kin selection hypothesis may be viable if male androphilia was expressed in the transgendered form in the ancestral past. Using the Standard Cross-Cultural Sample (SCCS), we examined 46 societies in which male androphilia was expressed in the transgendered form (transgendered societies) and 146 comparison societies (non-transgendered societies). We analyzed SCCS variables pertaining to ancestral sociocultural conditions, access to kin, and societal reactions to homosexuality. Our results show that ancestral sociocultural conditions and bilateral and double descent systems were more common in transgendered than in non-transgendered societies. Across the entire sample, descent systems and residence patterns that would presumably facilitate increased access to kin were associated with the presence of ancestral sociocultural conditions. Among transgendered societies, negative societal attitudes toward homosexuality were unlikely. We conclude that the ancestral human sociocultural environment was likely conducive to the expression of the transgendered form of male androphilia. Descent systems, residence patterns, and societal reactions to homosexuality likely facilitated investments in kin by transgendered males. Given that contemporary transgendered male androphiles appear to exhibit elevated kin-directed altruism, these findings further indicate the viability of the kin selection hypothesis.}, } @article {pmid24089101, year = {2013}, author = {Doncaster, CP and Jackson, A and Watson, RA}, title = {Competitive environments sustain costly altruism with negligible assortment of interactions.}, journal = {Scientific reports}, volume = {3}, number = {}, pages = {2836}, pmid = {24089101}, issn = {2045-2322}, mesh = {Adaptation, Biological ; *Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; *Ecosystem ; Models, Theoretical ; *Population Dynamics ; *Selection, Genetic ; }, abstract = {Competition hinders the evolution of altruism amongst kin when beneficiaries gain at the expense of competing relatives. Altruism is consequently deemed to require stronger kin selection, or trait-selected synergies, or elastic population regulation, to counter this effect. Here we contest the view that competition puts any such demands on altruism. In ecologically realistic scenarios, competition influences both altruism and defection. We show how environments that pit defectors against each other allow strong altruism to evolve even in populations with negligible kin structure and no synergies. Competition amongst defectors presents relative advantages to altruism in the simplest games between altruists and defectors, and the most generic models of altruistic phenotypes or genotypes invading non-altruistic populations under inelastic density regulation. Given the widespread inevitability of competition, selection will often favour altruism because its alternatives provide lower fitness. Strong competition amongst defectors nevertheless undermines altruism, by facilitating invasion of unrelated beneficiaries as parasites.}, } @article {pmid24088564, year = {2013}, author = {Port, M and Cant, MA}, title = {Longevity suppresses conflict in animal societies.}, journal = {Biology letters}, volume = {9}, number = {5}, pages = {20130680}, pmid = {24088564}, issn = {1744-957X}, mesh = {Animals ; Computer Simulation ; *Conflict, Psychological ; Cooperative Behavior ; Genetic Fitness/*physiology ; Longevity/*physiology ; *Models, Biological ; Mortality ; Selection, Genetic/physiology ; *Social Behavior ; }, abstract = {Models of social conflict in animal societies generally assume that within-group conflict reduces the value of a communal resource. For many animals, however, the primary cost of conflict is increased mortality. We develop a simple inclusive fitness model of social conflict that takes this cost into account. We show that longevity substantially reduces the level of within-group conflict, which can lead to the evolution of peaceful animal societies if relatedness among group members is high. By contrast, peaceful outcomes are never possible in models where the primary cost of social conflict is resource depletion. Incorporating mortality costs into models of social conflict can explain why many animal societies are so remarkably peaceful despite great potential for conflict.}, } @article {pmid24047091, year = {2013}, author = {Saad, G}, title = {The consuming instinct. What Darwinian consumption reveals about human nature.}, journal = {Politics and the life sciences : the journal of the Association for Politics and the Life Sciences}, volume = {32}, number = {1}, pages = {58-72}, doi = {10.2990/32_1_58}, pmid = {24047091}, issn = {1471-5457}, mesh = {*Biological Evolution ; Consumer Behavior ; Female ; *Human Characteristics ; Humans ; Male ; *Psychological Theory ; Selection, Genetic ; Sexual Behavior ; }, abstract = {Editor's note: In this engaging talk given last February on a particularly cold and blustery day at Texas Tech University, Professor Gad Saad of Concordia University discusses his work in the area of evolutionary consumption. In making the case for understanding consumerism from a Darwinian perspective, Saad addresses several key tenets from his books The Consuming Instinct (1) and The Evolutionary Bases of Consumption. (2) In particular, Saad argues that: (1) many consumption acts can be mapped onto four key Darwinian modules (survival, mating, kin selection, and reciprocal altruism); and, (2) cultural products such as song lyrics and movie plotlines are fossils of the human mind that highlight a shared, biologically based human nature. In this wide-ranging inquiry, Saad summarizes several of his other empirical works, including the effects of conspicuous consumption on men's testosterone levels (3) and how the ovulatory cycle in the human female influences consumption. (4) Overall, Professor Saad contends that an infusion of evolutionary and biologically based perspectives into the discipline of consumer behavior and related government regulatory policies yields myriad benefits, notably greater consilience, more effective practices, an ethos of interdisciplinarity, and methodological pluralism.}, } @article {pmid24033543, year = {2013}, author = {Preston, SA and Briskie, JV and Burke, T and Hatchwell, BJ}, title = {Genetic analysis reveals diverse kin-directed routes to helping in the rifleman Acanthisitta chloris.}, journal = {Molecular ecology}, volume = {22}, number = {19}, pages = {5027-5039}, doi = {10.1111/mec.12448}, pmid = {24033543}, issn = {1365-294X}, mesh = {Animals ; Female ; *Genetic Fitness ; Genotype ; *Helping Behavior ; Male ; Microsatellite Repeats ; New Zealand ; Passeriformes/*genetics ; Reproduction/genetics ; *Sexual Behavior, Animal ; }, abstract = {The social organization of cooperatively breeding species is extremely variable, with diverse social group composition and patterns of relatedness. Species that exhibit alternative routes to helping within the same population are potentially useful systems to investigate the causes and fitness consequences of diverse evolutionary pathways to cooperative behaviour. In this study, we use microsatellite markers and field observations to describe helping behaviour and patterns of relatedness in the unusual cooperative breeding system of the rifleman Acanthisitta chloris. First, we show that rifleman helpers consist of a remarkably diverse demographic, including males and females, who may be adult or juvenile, failed breeders or nonbreeders, or even successful breeders that simultaneously feed their own brood. Adult helpers mostly helped at first-brood nests, while first-brood juveniles assisted their parents at second broods. Second, we show that rifleman pairs are strictly sexually monogamous, and helpers did not gain any current reproductive success through helping. Third, genotyping showed that contrary to previous assumptions, helpers were closely related to the recipients of their care and preferentially directed care towards relatives over contemporaneous nests of nonrelatives. Finally, we show that variation in helper provisioning effort was attributed to age: juvenile helpers provisioned less than adults and were less responsive to the demands of a growing brood. Overall, our results show that the diverse routes to helping in this unusual species are driven by the common theme of kinship between helper and recipients, resulting in a previously underestimated potential for helpers to gain indirect fitness benefits.}, } @article {pmid24028471, year = {2013}, author = {Lion, S}, title = {Multiple infections, kin selection and the evolutionary epidemiology of parasite traits.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {10}, pages = {2107-2122}, doi = {10.1111/jeb.12207}, pmid = {24028471}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; Coinfection/*parasitology ; *Host-Parasite Interactions ; *Models, Biological ; Parasites/*pathogenicity/physiology ; Virulence ; }, abstract = {The coinfection of a host by several parasite strains is known to affect selective pressures on parasite strategies of host exploitation. I present a general model of coinfections that ties together kin selection models of virulence evolution and epidemiological models of multiple infections. I derive an analytical expression for the invasion fitness of a rare mutant in a population with an arbitrary distribution of the multiplicity of infection (MOI) across hosts. When a single mutation affects parasite strategies in all MOI classes, I show that the evolutionarily stable level of virulence depends on a demographic average of within-host relatedness across all host classes. This generalization of previous kin selection results requires that within-host parasite densities do not vary between hosts. When host exploitation strategies are allowed to vary across classes, I show that the strategy of host exploitation in a focal MOI class depends on the relative magnitudes of parasite reproductive values in the focal class and in the next. Thus, in contrast to previous findings, lower within-host relatedness in competitive parasite interactions can potentially correspond to either higher or lower levels of virulence.}, } @article {pmid24004898, year = {2013}, author = {Moore, D and Wigby, S and English, S and Wong, S and Székely, T and Harrison, F}, title = {Selflessness is sexy: reported helping behaviour increases desirability of men and women as long-term sexual partners.}, journal = {BMC evolutionary biology}, volume = {13}, number = {}, pages = {182}, pmid = {24004898}, issn = {1471-2148}, mesh = {Adult ; Altruism ; *Biological Evolution ; Choice Behavior ; Female ; *Helping Behavior ; Humans ; Male ; *Marriage ; Young Adult ; }, abstract = {BACKGROUND: Despite its short-term costs, behaviour that appears altruistic can increase an individual's inclusive fitness by earning direct (selfish) and/or indirect (kin-selected) benefits. An evolved preference for other-regarding or helping behaviour in potential mates has been proposed as an additional mechanism by which these behaviours can yield direct fitness benefits in humans.

RESULTS: We asked 32 heterosexual women and 35 heterosexual men to rate the attractiveness of members of the opposite sex in the presence and the absence of information about helping behaviours. Reports of helping behaviour were associated with a significant increase in the attractiveness of both men and women as potential long-term sexual partners. Altruism also increased the attractiveness of men as potential partners for short-term flings, but to a lesser extent than when the same men were being considered for long-term relationships. Altruism did not affect the attractiveness of women as partners for short-term flings.

CONCLUSIONS: Our results unite two important areas of evolutionary theory - social evolution and sexual selection - and extend the list of means by which helping behaviours, which appear at first glance to be costly to the actor, can in fact earn direct fitness benefits. Helping behaviours may be attractive because they signal 'good genes' and/or because they are perceived as a signal of likely provision of non-genetic benefits (e.g. parental care). Exactly why helping behaviours in a non-mating context might be attractive to potential mates, and whether they are honest signals of mate quality, remains to be elucidated.}, } @article {pmid23945693, year = {2013}, author = {Jaeggi, AV and Gurven, M}, title = {Reciprocity explains food sharing in humans and other primates independent of kin selection and tolerated scrounging: a phylogenetic meta-analysis.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1768}, pages = {20131615}, pmid = {23945693}, issn = {1471-2954}, mesh = {Animals ; *Cooperative Behavior ; *Helping Behavior ; Humans ; Phylogeny ; Primates/*psychology ; Species Specificity ; }, abstract = {Helping, i.e. behaviour increasing the fitness of others, can evolve when directed towards kin or reciprocating partners. These predictions have been tested in the context of food sharing both in human foragers and non-human primates. Here, we performed quantitative meta-analyses on 32 independent study populations to (i) test for overall effects of reciprocity on food sharing while controlling for alternative explanations, methodological biases, publication bias and phylogeny and (ii) compare the relative effects of reciprocity, kinship and tolerated scrounging, i.e. sharing owing to costs imposed by others. We found a significant overall weighted effect size for reciprocity of r = 0.20-0.48 for the most and least conservative measure, respectively. Effect sizes did not differ between humans and other primates, although there were species differences in in-kind reciprocity and trade. The relative effect of reciprocity in sharing was similar to those of kinship and tolerated scrounging. These results indicate a significant independent contribution of reciprocity to human and primate helping behaviour. Furthermore, similar effect sizes in humans and primates speak against cognitive constraints on reciprocity. This study is the first to use meta-analyses to quantify these effects on human helping and to directly compare humans and other primates.}, } @article {pmid23910660, year = {2013}, author = {Naeger, NL and Peso, M and Even, N and Barron, AB and Robinson, GE}, title = {Altruistic behavior by egg-laying worker honeybees.}, journal = {Current biology : CB}, volume = {23}, number = {16}, pages = {1574-1578}, doi = {10.1016/j.cub.2013.06.045}, pmid = {23910660}, issn = {1879-0445}, support = {1DP10D006416/DP/NCCDPHP CDC HHS/United States ; }, mesh = {Altruism ; Animals ; Bees/genetics/*physiology ; Female ; *Nesting Behavior ; New South Wales ; Reproduction ; Selection, Genetic ; Social Behavior ; }, abstract = {If a honeybee (Apis mellifera) colony loses its queen, worker bees develop their ovaries and produce male offspring [1]. Kin selection theory predicts that the degree of altruism in queenless colonies should be reduced because the relatedness of workers to a hivemate's offspring is less in queenless colonies than it is to the daughters of the queen in queenright colonies [2-4]. To explore this hypothesis, we examined the behavior and physiology of queenless egg-laying workers. Queenless bees engaged in both personal reproduction and the social foraging and defense tasks that benefited their colony. Laying workers also had larger brood-food-producing and wax glands, showing metabolic investments in both colony maintenance and personal reproduction. Whereas in queenright colonies there is a very clear age-based pattern of division of labor between workers, in queenless colonies the degree of individual specialization was much reduced. Queenless colonies functioned as a collective of reproductive and behaviorally generalist bees that cooperatively maintained and defended their nest. This social structure is similar to that observed in a number of primitively social bee species [5]. Laying workers therefore show a mix of selfish personal reproduction and altruistic cooperative behavior, and the queenless state reveals previously unrecognized plasticity in honeybee social organization.}, } @article {pmid23895053, year = {2013}, author = {Satow, S and Satoh, T and Hirota, T}, title = {Colony fusion in a parthenogenetic ant, Pristomyrmex punctatus.}, journal = {Journal of insect science (Online)}, volume = {13}, number = {}, pages = {38}, pmid = {23895053}, issn = {1536-2442}, mesh = {*Aggression ; Animals ; *Ants ; Competitive Behavior ; Female ; *Nesting Behavior ; Parthenogenesis ; }, abstract = {In the ant Pristomyrmex punctatus Smith (Hymenoptera: Formicidae), all young workers lay a small number of eggs parthenogenetically. Some colonies consist of monoclonal individuals that provide high inclusive fitness, according to the kin selection theory. However, in some populations, a majority of the colonies contain multiple lineages. Intracolonial genetic variation of parthenogenetic ants cannot be explained by the multiple mating of single founderesses or by the foundation of a colony by multiple foundresses, which are the usual causes of genetically diverse colonies in social insects. Here, we hypothesized that the fusion of established colonies might facilitate the formation of multiclonal colonies. Colony fusion decreases indirect benefits because of the reduction in intracolonial relatedness. However, when suitable nesting places for overwintering are scarce, colony fusion provides a strategy for the survival of colonies. Here, ants derived from different colonies were allowed to encounter one another in a container with just one nesting place. Initially, high aggression was observed; however, after several days, no aggression was observed and the ants shared the nest. When the fused colonies were allowed to transfer to two alternative nests, ants from different colonies occupied the same nest. This study highlights the importance of limiting the number of nesting places in order to understand the genetic diversity of parthenogenetic ant colonies.}, } @article {pmid23889604, year = {2013}, author = {Holmes, MJ and Oldroyd, BP and Duncan, M and Allsopp, MH and Beekman, M}, title = {Cheaters sometimes prosper: targeted worker reproduction in honeybee (Apis mellifera) colonies during swarming.}, journal = {Molecular ecology}, volume = {22}, number = {16}, pages = {4298-4306}, doi = {10.1111/mec.12387}, pmid = {23889604}, issn = {1365-294X}, mesh = {Animals ; Bees/*genetics/*physiology ; Female ; Genotype ; Male ; Pupa/genetics ; *Reproduction/genetics/physiology ; Sexual Behavior, Animal/*physiology ; Social Behavior ; }, abstract = {Kin selection theory predicts that honeybee (Apis mellifera) workers should largely refrain from producing their own offspring, as the workers collectively have higher inclusive fitness if they rear the sons of their mother, the queen. Studies that have quantified levels of ovary activation and reproduction among workers have largely supported this prediction. We sampled pre-emergent male pupae and adult workers from seven colonies at regular intervals throughout the reproductive part of the season. We show that the overall contribution of workers to male (drone) production is 4.2%, nearly 40 times higher than is generally reported, and is highest during reproductive swarming, when an average of 6.2% of the males genotyped are worker-produced. Similarly, workers in our samples were 100 times more likely to have active ovaries than previously assumed. Worker reproduction is seasonally influenced and peaks when colonies are rearing new queens. Not all worker subfamilies contribute equally to reproduction. Instead, certain subfamilies are massively over-represented in drone brood. By laying eggs within the period in which many colonies produce virgin queens, these rare worker subfamilies increase their direct fitness via their well-timed sons.}, } @article {pmid23888851, year = {2013}, author = {Rodrigues, AM and Gardner, A}, title = {Evolution of helping and harming in heterogeneous groups.}, journal = {Evolution; international journal of organic evolution}, volume = {67}, number = {8}, pages = {2284-2298}, doi = {10.1111/evo.12110}, pmid = {23888851}, issn = {1558-5646}, mesh = {Amoeba/genetics/physiology ; Animals ; *Biological Evolution ; Helping Behavior ; Models, Biological ; *Social Behavior ; Wasps/genetics/physiology ; }, abstract = {Social groups are often composed of individuals who differ in many respects. Theoretical studies on the evolution of helping and harming behaviors have largely focused upon genetic differences between individuals. However, nongenetic variation between group members is widespread in natural populations, and may mediate differences in individuals' social behavior. Here, we develop a framework to study how variation in individual quality mediates the evolution of unconditional and conditional social traits. We investigate the scope for the evolution of social traits that are conditional on the quality of the actor and/or recipients. We find that asymmetries in individual quality can lead to the evolution of plastic traits with different individuals expressing helping and harming traits within the same group. In this context, population viscosity can mediate the evolution of social traits, and local competition can promote both helping and harming behaviors. Furthermore, asymmetries in individual quality can lead to the evolution of competition-like traits between clonal individuals. Overall, we highlight the importance of asymmetries in individual quality, including differences in reproductive value and the ability to engage in successful social interactions, in mediating the evolution of helping and harming behaviors.}, } @article {pmid23856025, year = {2013}, author = {Rand, DG and Nowak, MA}, title = {Human cooperation.}, journal = {Trends in cognitive sciences}, volume = {17}, number = {8}, pages = {413-425}, doi = {10.1016/j.tics.2013.06.003}, pmid = {23856025}, issn = {1879-307X}, mesh = {Choice Behavior ; *Cooperative Behavior ; Humans ; Interpersonal Relations ; *Models, Psychological ; }, abstract = {Why should you help a competitor? Why should you contribute to the public good if free riders reap the benefits of your generosity? Cooperation in a competitive world is a conundrum. Natural selection opposes the evolution of cooperation unless specific mechanisms are at work. Five such mechanisms have been proposed: direct reciprocity, indirect reciprocity, spatial selection, multilevel selection, and kin selection. Here we discuss empirical evidence from laboratory experiments and field studies of human interactions for each mechanism. We also consider cooperation in one-shot, anonymous interactions for which no mechanisms are apparent. We argue that this behavior reflects the overgeneralization of cooperative strategies learned in the context of direct and indirect reciprocity: we show that automatic, intuitive responses favor cooperative strategies that reciprocate.}, } @article {pmid23852350, year = {2013}, author = {Ratcliff, WC and Hoverman, M and Travisano, M and Denison, RF}, title = {Disentangling direct and indirect fitness effects of microbial dormancy.}, journal = {The American naturalist}, volume = {182}, number = {2}, pages = {147-156}, doi = {10.1086/670943}, pmid = {23852350}, issn = {1537-5323}, mesh = {*Biological Evolution ; *Models, Biological ; Saccharomyces cerevisiae/*physiology ; *Selection, Genetic ; }, abstract = {Disentangling individual selection from kin selection is one of the greatest challenges of evolutionary biology. Even solitary organisms that do not interact directly with conspecifics may interact indirectly with them through competition for resources. As a result, traits that appear to affect individual fitness alone can also modify the fitness of relatives nearby and thus may evolve partially through these cryptic indirect fitness effects. Here we develop a method to quantitatively separate direct and indirect fitness consequences when some microbes become dormant, while neighbors of the same genotype remain active. Dormant microbes typically survive stresses that kill metabolically active cells, but dormancy also has a social side effect, sparing resources that may be used by nondormant individuals for growth. In structured populations, spared resources may be preferentially consumed by nondormant clonemates, providing an indirect benefit. Without population structure, however, exploitation by a never-dormant competitor imposes an indirect fitness cost on dormant cells. Cryptic indirect fitness effects may play a significant role in the evolution of many ostensibly asocial traits.}, } @article {pmid23848984, year = {2013}, author = {Alizon, S}, title = {On the limits of interpreting some plastic responses through a cooperator/cheater prism. A comment on Harrison.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {9}, pages = {2051-2056}, doi = {10.1111/jeb.12199}, pmid = {23848984}, issn = {1420-9101}, mesh = {Pseudomonas aeruginosa/*physiology ; Siderophores/*metabolism ; }, abstract = {Micro-organisms are known to exhibit phenotypic plasticity in response to changes in their environment. Recent studies have shown that a parasite strain can adjust its host exploitation strategies to the presence of unrelated strains, e.g. for Plasmodium chabaudi by adjusting its sex-ratio. J. Evol. Biol. 2013; 26: 1370-1378 claims to report a similar plastic response to the presence of unrelated strains in the case of siderophore-producing bacteria. I argue that she does not provide sufficient evidence to support the interpretation of the plastic response she observes (increasing siderophore production in the presence of cheaters) through a cooperator/cheater framework. I show that known plastic responses to physicochemical factors, such as siderophore or iron concentration, seem to offer a clearer and more parsimonious explanation. Finally, I also challenge the parallel she makes between the process she observes in siderophore-producing bacteria and compensation in bi-parental care models.}, } @article {pmid23848844, year = {2013}, author = {Wyatt, GA and West, SA and Gardner, A}, title = {Can natural selection favour altruism between species?.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {9}, pages = {1854-1865}, doi = {10.1111/jeb.12195}, pmid = {23848844}, issn = {1420-9101}, support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Altruism ; *Biological Evolution ; Genetic Fitness/*genetics ; *Genetics, Population ; Linear Models ; *Models, Genetic ; *Selection, Genetic ; Species Specificity ; }, abstract = {Darwin suggested that the discovery of altruism between species would annihilate his theory of natural selection. However, it has not been formally shown whether between-species altruism can evolve by natural selection, or why this could never happen. Here, we develop a spatial population genetic model of two interacting species, showing that indiscriminate between species helping can be favoured by natural selection. We then ask if this helping behaviour constitutes altruism between species, using a linear-regression analysis to separate the total action of natural selection into its direct and indirect (kin selected) components. We show that our model can be interpreted in two ways, as either altruism within species, or altruism between species. This ambiguity arises depending on whether or not we treat genes in the other species as predictors of an individual's fitness, which is equivalent to treating these individuals as agents (actors or recipients). Our formal analysis, which focuses upon evolutionary dynamics rather than agents and their agendas, cannot resolve which is the better approach. Nonetheless, because a within-species altruism interpretation is always possible, our analysis supports Darwin's suggestion that natural selection does not favour traits that provide benefits exclusively to individuals of other species.}, } @article {pmid23845249, year = {2013}, author = {West, SA and Gardner, A}, title = {Adaptation and inclusive fitness.}, journal = {Current biology : CB}, volume = {23}, number = {13}, pages = {R577-84}, doi = {10.1016/j.cub.2013.05.031}, pmid = {23845249}, issn = {1879-0445}, mesh = {*Adaptation, Biological ; Biological Evolution ; *Genetic Fitness ; Genome ; Humans ; Phenotype ; Reproduction ; *Selection, Genetic ; }, abstract = {Inclusive fitness theory captures how individuals can influence the transmission of their genes to future generations by influencing either their own reproductive success or that of related individuals. This framework is frequently used for studying the way in which natural selection leads to organisms being adapted to their environments. A number of recent papers have criticised this approach, suggesting that inclusive fitness is just one of many possible mathematical methods for modelling when traits will be favoured by natural selection, and that it leads to errors, such as overemphasising the role of common ancestry relative to other mechanisms that could lead to individuals being genetically related. Here, we argue that these suggested problems arise from a misunderstanding of two fundamental points: first, inclusive fitness is more than just a mathematical 'accounting method' - it is the answer to the question of what organisms should appear designed to maximise; second, there is something special about relatedness caused by common ancestry, in contrast with the other mechanisms that may lead to individuals being genetically related, because it unites the interests of genes across the genome, allowing complex, multigenic adaptations to evolve. The critiques of inclusive fitness theory have provided neither an equally valid answer to the question of what organisms should appear designed to maximise, nor an alternative process to unite the interest of genes. Consequently, inclusive fitness remains the most general theory for explaining adaptation.}, } @article {pmid23825662, year = {2013}, author = {Chong, G and Kimyon, O and Manefield, M}, title = {Quorum Sensing Signal Synthesis May Represent a Selective Advantage Independent of Its Role in Regulation of Bioluminescence in Vibrio fischeri.}, journal = {PloS one}, volume = {8}, number = {6}, pages = {e67443}, pmid = {23825662}, issn = {1932-6203}, mesh = {Aliivibrio fischeri/*physiology ; *Luminescence ; Quorum Sensing ; }, abstract = {The evolution of biological signalling systems and apparently altruistic or cooperative traits in diverse organisms has required selection against the subversive tendencies of self-interested biological entities. The bacterial signalling and response system known as quorum sensing or Acylated Homoserine Lactone (AHL) mediated gene expression is thought to have evolved through kin selection. In this in vitro study on the model quorum sensing bioluminescent marine symbiont Vibrio fischeri, competition and long-term sub culturing experiments suggest that selection for AHL synthesis (encoded by the AHL synthase gene luxI) is independent of the quorum sensing regulated phenotype (bioluminescence encoded by luxCDABE). Whilst results support the hypothesis that signal response (AHL binding and transcriptional activation encoded by the luxR gene) is maintained through indirect fitness benefits (kin selection), signal synthesis is maintained in the V. fischeri genome over evolutionary time through direct fitness benefits at the individual level from an unknown function.}, } @article {pmid23817946, year = {2013}, author = {Morelli, TL and Hayes, RA and Nahrung, HF and Goodwin, TE and Harelimana, IH and Macdonald, LJ and Wright, PC}, title = {Relatedness communicated in lemur scent.}, journal = {Die Naturwissenschaften}, volume = {100}, number = {8}, pages = {769-777}, pmid = {23817946}, issn = {1432-1904}, mesh = {*Animal Communication ; Animals ; Female ; Gas Chromatography-Mass Spectrometry ; Lemur/genetics/*physiology ; Madagascar ; Male ; Multivariate Analysis ; Pheromones/*chemistry/genetics ; Scent Glands/chemistry ; }, abstract = {Lemurs are the most olfactory-oriented of primates, yet there is still only a basic level of understanding of what their scent marks communicate. We analyzed scent secretions from Milne-Edwards' sifakas (Propithecus edwardsi) collected in their natural habitat of Ranomafana National Park, Madagascar. We sought to test whether the scent mark could signal genetic relatedness in addition to species, sex, season, and individuality. We not only found correlations (r (2) = 0.38, P = 0.017) between the total olfactory fingerprint and genetic relatedness but also between relatedness and specific components of the odor, despite the complex environmental signals from differences in diet and behavior in a natural setting. To the best of our knowledge, this is the first demonstration of an association between genetic relatedness and chemical communication in a wild primate population. Furthermore, we found a variety of compounds that were specific to each sex and each sampling period. This research shows that scent marks could act as a remote signal to avoid inbreeding, optimize mating opportunities, and potentially aid kin selection.}, } @article {pmid23807025, year = {2013}, author = {Kobayashi, K and Hasegawa, E and Yamamoto, Y and Kawatsu, K and Vargo, EL and Yoshimura, J and Matsuura, K}, title = {Sex ratio biases in termites provide evidence for kin selection.}, journal = {Nature communications}, volume = {4}, number = {}, pages = {2048}, doi = {10.1038/ncomms3048}, pmid = {23807025}, issn = {2041-1723}, mesh = {Animals ; Female ; Hierarchy, Social ; Inbreeding ; Isoptera/growth & development/*physiology ; Life Cycle Stages ; Male ; Models, Biological ; Reproduction, Asexual/physiology ; *Selection, Genetic ; *Sex Ratio ; *Sexism ; Social Behavior ; }, abstract = {Inclusive fitness theory, also known as kin selection theory, is the most general expansion of Darwin's natural selection theory. It is supported by female-biased investment by workers in the social Hymenoptera where relatedness to sisters is higher than to brothers because of haplodiploidy. However, a strong test of the theory has proven difficult in diploid social insects because they lack such relatedness asymmetry. Here we show that kin selection can result in sex ratio bias in eusocial diploids. Our model predicts that allocation will be biased towards the sex that contributes more of its genes to the next generation when sex-asymmetric inbreeding occurs. The prediction matches well with the empirical sex allocation of Reticulitermes termites where the colony king can be replaced by a queen's son. Our findings open broad new avenues to test inclusive fitness theory beyond the well-studied eusocial Hymenoptera.}, } @article {pmid23805291, year = {2013}, author = {Brante, A and Fernández, M and Viard, F}, title = {Non-Random Sibling Cannibalism in the Marine Gastropod Crepidula coquimbensis.}, journal = {PloS one}, volume = {8}, number = {6}, pages = {e67050}, pmid = {23805291}, issn = {1932-6203}, mesh = {Animals ; Behavior, Animal/physiology ; *Cannibalism ; DNA/isolation & purification/metabolism ; Female ; Gastropoda/genetics/*physiology ; Genotype ; Male ; Microsatellite Repeats ; Siblings ; }, abstract = {Sibling cannibalism is commonly observed in marine species. For instance, intrabrood cannibalism has been documented in marine gastropods with direct development, suggesting a relationship between embryo behavior and the evolution of life history strategies. However, there has been little effort to document the factors driving sibling cannibalism in marine species. The kin selection theory suggests that the level of relatedness plays an important role in cannibalism patterns. We examined Crepidula coquimbensis, a marine gastropod that broods and encloses its brooded offspring in capsules. Encapsulated embryos show sibling cannibalism and high levels of intracapsular multiple paternity. Given these features, cannibalistic behavior may be driven by kin-relatedness. To test this hypothesis, we constructed artificial aggregations of embryos to mimic three levels of relatedness: high, medium and low. For each category of aggregation, the cannibalism rate and benefits (i.e. size at hatching of surviving offspring) were estimated. In addition, at the end of embryo development, we performed parentage analyses to determine if cannibalism was associated with the relatedness between cannibal and victim embryos. Our results show that the intensity of sibling cannibalism increased in aggregations characterized by the lowest level of relatedness. There were important benefits of cannibalism in terms of hatching cannibal size. In addition, cannibalism between embryos was not random: the variation in reproductive success between males increased over the course of the experiment and the effective number of fathers decreased. Altogether, these results suggest that polyandry may play an important role in the evolution of sibling cannibalism in C. coquimbensis and that kin selection may operate during early embryonic stages in this species.}, } @article {pmid23785268, year = {2013}, author = {Morton, RA and Stone, JR and Singh, RS}, title = {Mate choice and the origin of menopause.}, journal = {PLoS computational biology}, volume = {9}, number = {6}, pages = {e1003092}, pmid = {23785268}, issn = {1553-7358}, mesh = {Female ; Humans ; Male ; *Menopause/genetics ; Mutation ; *Sexual Behavior ; }, abstract = {Human menopause is an unsolved evolutionary puzzle, and relationships among the factors that produced it remain understood poorly. Classic theory, involving a one-sex (female) model of human demography, suggests that genes imparting deleterious effects on post-reproductive survival will accumulate. Thus, a 'death barrier' should emerge beyond the maximum age for female reproduction. Under this scenario, few women would experience menopause (decreased fertility with continued survival) because few would survive much longer than they reproduced. However, no death barrier is observed in human populations. Subsequent theoretical research has shown that two-sex models, including male fertility at older ages, avoid the death barrier. Here we use a stochastic, two-sex computational model implemented by computer simulation to show how male mating preference for younger females could lead to the accumulation of mutations deleterious to female fertility and thus produce a menopausal period. Our model requires neither the initial assumption of a decline in older female fertility nor the effects of inclusive fitness through which older, non-reproducing women assist in the reproductive efforts of younger women. Our model helps to explain why such effects, observed in many societies, may be insufficient factors in elucidating the origin of menopause.}, } @article {pmid23769953, year = {2013}, author = {Baron, C}, title = {The handicap principle and the argument of subversion from within.}, journal = {Studies in history and philosophy of biological and biomedical sciences}, volume = {44}, number = {3}, pages = {347-355}, doi = {10.1016/j.shpsc.2013.05.001}, pmid = {23769953}, issn = {1879-2499}, mesh = {*Altruism ; *Biological Evolution ; Humans ; *Selection, Genetic ; }, abstract = {This paper examines the very disparate positions that various actors have taken towards the argument of subversion from within (a classical argument against the evolution of altruism by group selection) in a set of related debates on group selection, altruism and the handicap principle. Using this set of debates as a case study, this paper argues that different applications of epistemic values were one of the factors behind the disagreements between John Maynard Smith and Amotz Zahavi over a number of important evolutionary issues. The paper also argues that these different applications were connected to important epistemological differences related in part (but not solely) to their disciplinary background. Apart from conflicting evolutionary views concerning the theoretical feasibility of the handicap effect, these antagonists both differed in the confidence they ascribed to mathematical modeling and over the hereditary basis for altruistic behavior.}, } @article {pmid23760639, year = {2013}, author = {Mc Ginty, SÉ and Lehmann, L and Brown, SP and Rankin, DJ}, title = {The interplay between relatedness and horizontal gene transfer drives the evolution of plasmid-carried public goods.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1761}, pages = {20130400}, pmid = {23760639}, issn = {1471-2954}, support = {095831/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Bacteria/*genetics/pathogenicity ; *Biological Evolution ; *Gene Transfer, Horizontal ; Genetics, Population ; Host-Pathogen Interactions/genetics ; *Models, Genetic ; Plasmids/*genetics ; Selection, Genetic ; Virulence Factors/genetics ; }, abstract = {Plasmids carry a wide range of genes that are often involved in bacterial social behaviour. The question of why such genes are frequently mobile has received increasing attention. Here, we use an explicit population genetic approach to model the evolution of plasmid-borne bacterial public goods production. Our findings highlight the importance of both transmission and relatedness as factors driving the evolution of plasmid-borne public goods production. We partition the effects of plasmid transfer of social traits into those of infectivity and the effect of increased relatedness. Our results demonstrate that, owing to its effect on relatedness, plasmid mobility increases the invasion and stability of public goods, in a way not seen in individually beneficial traits. In addition, we show that plasmid transfer increases relatedness when public goods production is rare but this effect declines when production is common, with both scenarios leading to an increase in the frequency of plasmid-borne public goods. Plasmids remain important vectors for the spread of social genes involved in bacterial virulence thus an understanding of their dynamics is highly relevant from a public health perspective.}, } @article {pmid23730751, year = {2013}, author = {Simon, B and Fletcher, JA and Doebeli, M}, title = {Towards a general theory of group selection.}, journal = {Evolution; international journal of organic evolution}, volume = {67}, number = {6}, pages = {1561-1572}, doi = {10.1111/j.1558-5646.2012.01835.x}, pmid = {23730751}, issn = {1558-5646}, mesh = {Animals ; Evolution, Molecular ; Markov Chains ; *Models, Genetic ; Population/genetics ; *Selection, Genetic ; }, abstract = {The longstanding debate about the importance of group (multilevel) selection suffers from a lack of formal models that describe explicit selection events at multiple levels. Here, we describe a general class of models for two-level evolutionary processes which include birth and death events at both levels. The models incorporate the state-dependent rates at which these events occur. The models come in two closely related forms: (1) a continuous-time Markov chain, and (2) a partial differential equation (PDE) derived from (1) by taking a limit. We argue that the mathematical structure of this PDE is the same for all models of two-level population processes, regardless of the kinds of events featured in the model. The mathematical structure of the PDE allows for a simple and unambiguous way to distinguish between individual- and group-level events in any two-level population model. This distinction, in turn, suggests a new and intuitively appealing way to define group selection in terms of the effects of group-level events. We illustrate our theory of group selection by applying it to models of the evolution of cooperation and the evolution of simple multicellular organisms, and then demonstrate that this kind of group selection is not mathematically equivalent to individual-level (kin) selection.}, } @article {pmid23730749, year = {2013}, author = {Goodnight, C}, title = {On multilevel selection and kin selection: contextual analysis meets direct fitness.}, journal = {Evolution; international journal of organic evolution}, volume = {67}, number = {6}, pages = {1539-1548}, doi = {10.1111/j.1558-5646.2012.01821.x}, pmid = {23730749}, issn = {1558-5646}, mesh = {Animals ; Evolution, Molecular ; *Genetic Fitness ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {When Hamilton defined the concept of inclusive fitness, he specifically was looking to define the fitness of an individual in terms of that individual's behavior, and the effects of its' behavior on other related individuals. Although an intuitively attractive concept, issues of accounting for fitness, and correctly assigning it to the appropriate individual make this approach difficult to implement. The direct fitness approach has been suggested as a means of modeling kin selection while avoiding these issues. Whereas Hamilton's inclusive fitness approach assigns to the focal individual the fitness effects of its behavior on other related individuals, the direct fitness approach assigns the fitness effects of other actors to the focal individual. Contextual analysis was independently developed as a quantitative genetic approach for measuring multilevel selection in natural populations. Although the direct fitness approach and contextual analysis come from very different traditions, both methods rely on the same underlying equation, with the primary difference between the two approaches being that the direct fitness approach uses fitness optimization modeling, whereas with contextual analysis, the same equation is used to solve for the change in fitness associated with a change in phenotype when the population is away from the optimal phenotype.}, } @article {pmid23717479, year = {2013}, author = {Ale, SB and Brown, JS and Sullivan, AT}, title = {Evolution of cooperation: combining kin selection and reciprocal altruism into matrix games with social dilemmas.}, journal = {PloS one}, volume = {8}, number = {5}, pages = {e63761}, pmid = {23717479}, issn = {1932-6203}, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Cooperative Behavior ; *Game Theory ; *Interpersonal Relations ; }, abstract = {Darwinian selection should preclude cooperation from evolving; yet cooperation is widespread among organisms. We show how kin selection and reciprocal altruism can promote cooperation in diverse 2×2 matrix games (prisoner's dilemma, snowdrift, and hawk-dove). We visualize kin selection as non-random interactions with like-strategies interacting more than by chance. Reciprocal altruism emerges from iterated games where players have some likelihood of knowing the identity of other players. This perspective allows us to combine kin selection and reciprocal altruism into a general matrix game model. Both mechanisms operating together should influence the evolution of cooperation. In the absence of kin selection, reciprocal altruism may be an evolutionarily stable strategy but is unable to invade a population of non-co-operators. Similarly, it may take a high degree of relatedness to permit cooperation to supplant non-cooperation. Together, a little bit of reciprocal altruism can, however, greatly reduce the threshold at which kin selection promotes cooperation, and vice-versa. To properly frame applications and tests of cooperation, empiricists should consider kin selection and reciprocal altruism together rather than as alternatives, and they should be applied to a broader class of social dilemmas than just the prisoner's dilemma.}, } @article {pmid23714691, year = {2013}, author = {Cable, J and Archard, GA and Mohammed, RS and McMullan, M and Stephenson, JF and Hansen, H and van Oosterhout, C}, title = {Can parasites use predators to spread between primary hosts?.}, journal = {Parasitology}, volume = {140}, number = {9}, pages = {1138-1143}, doi = {10.1017/S003118201300067X}, pmid = {23714691}, issn = {1469-8161}, mesh = {Animals ; Ectoparasitic Infestations/parasitology/transmission/*veterinary ; Fish Diseases/parasitology/*transmission ; Host-Parasite Interactions ; Killifishes/*parasitology ; Platyhelminths/*physiology ; Poecilia/*parasitology ; Time Factors ; Trematode Infections/parasitology/transmission/veterinary ; }, abstract = {Parasites typically have low reproductive fitness on paratenic hosts. Such hosts offer other significant inclusive fitness benefits to parasites, however, such as increased mobility and migration potential. The parasite fauna of the guppy (Poecilia reticulata) is dominated by the directly transmitted ectoparasites Gyrodactylus bullatarudis and Gyrodactylus turnbulli. In the wild, close predatory and competitive interactions occur between the guppy and the killifish Rivulus hartii. Previous observations suggest that these fish can share gyrodactylids, so we tested experimentally whether these parasites can use R. hartii as an alternative host. In aquaria, G. bullatarudis was the only species able to transmit from prey to predator. Both parasite species transferred equally well to prey when the predator was experimentally infected. However, in semi-natural conditions, G. bullatarudis transmitted more successfully to the prey fish. Importantly, G. bullatarudis also survived significantly longer on R. hartii out of water. As R. hartii can migrate overland between isolated guppy populations, G. bullatarudis may have an enhanced ability to disperse and colonize new host populations, consistent with its wider distribution in the wild. To our knowledge, this is the first empirical study demonstrating a predator acting as a paratenic host for the parasites of its prey.}, } @article {pmid23710754, year = {2013}, author = {Luchetti, A and Dedeine, F and Velonà, A and Mantovani, B}, title = {Extreme genetic mixing within colonies of the wood-dwelling termite Kalotermes flavicollis (Isoptera, Kalotermitidae).}, journal = {Molecular ecology}, volume = {22}, number = {12}, pages = {3391-3402}, doi = {10.1111/mec.12302}, pmid = {23710754}, issn = {1365-294X}, mesh = {Animals ; Cell Nucleus/genetics ; DNA, Mitochondrial/genetics ; Genetic Variation ; Isoptera/*genetics ; Microsatellite Repeats ; Molecular Sequence Data ; Reproduction/genetics ; Sequence Analysis, DNA ; }, abstract = {The existence of altruism in social insects is commonly attributed to altruistic individuals gaining indirect fitness through kin selection. However, recent studies suggest that such individuals might also gain direct fitness through reproduction. Experimental studies on primitive wood-dwelling termites revealed that colony fusion often causes the death of primary reproductives (queen and king), allowing opportunities for workers to inherit the nest by developing into replacement reproductives (neotenics). Therefore, colony fusion has been proposed as an important factor that may have favoured sociality in termites. However, whether colony fusion occurs frequently in natural populations of wood-dwelling termites remains an open question. We analysed eleven colonies of the wood-dwelling termite Kalotermes flavicollis (Kalotermitidae), using two mitochondrial and five nuclear microsatellite markers. Nine of eleven colonies (82%) were mixed families, with offspring of three or more primary reproductives. To our knowledge, this result represents the highest frequency of mixed-family colonies ever reported in termites. Moreover, genetic mixing of colonies appeared extreme in two ways. First, the number of haplotypes per colony was exceptionally high (up to nine), indicating that colonies were composed of multiple queens' offspring. Second, some mixed-family colonies included individuals belonging to two highly divergent genetic lineages. F-statistics and relatedness values suggest that mixed-family colonies most likely result from colony fusion, giving support to the accelerated nest inheritance theory. These findings raise important questions about the mode of foundation of mixed-family colonies and the evolutionary forces that maintain them within populations.}, } @article {pmid23684769, year = {2013}, author = {Sozou, PD}, title = {Kin selection and local competition in a heterogeneous community.}, journal = {Journal of theoretical biology}, volume = {332}, number = {}, pages = {261-266}, doi = {10.1016/j.jtbi.2013.05.003}, pmid = {23684769}, issn = {1095-8541}, mesh = {Animals ; *Models, Biological ; *Selection, Genetic ; *Social Behavior ; }, abstract = {When should an individual be willing to pay a cost in order to help or harm another individual in its community? Kin selection suggests that relatives should help each other, while competition for limited resources may select for harming behaviour against neighbours. This study considers social interactions between two individuals. For actions influencing non-dispersing reproduction, a condition is derived for selection to favour helping or harming, as a function of the actor's relationship to the rest of its community and to the recipient. Where two individuals differ in their relatedness to the community, the individual which is less related to the community will be the more helpful. Two individuals with a given relatedness to each other will be more helpful to each other as they jointly become less related to their community. The implications of these results are explored through an example involving a community derived from two ancestral groups. The directional selective effects will depend on the extent to which social interactions are assortative rather than random, and the distribution of opportunities for helping and harming.}, } @article {pmid23682605, year = {2013}, author = {Schuster, M and Sexton, DJ and Diggle, SP and Greenberg, EP}, title = {Acyl-homoserine lactone quorum sensing: from evolution to application.}, journal = {Annual review of microbiology}, volume = {67}, number = {}, pages = {43-63}, doi = {10.1146/annurev-micro-092412-155635}, pmid = {23682605}, issn = {1545-3251}, support = {P30 DK089507/DK/NIDDK NIH HHS/United States ; GM-59026/GM/NIGMS NIH HHS/United States ; P30 DK 89507/DK/NIDDK NIH HHS/United States ; }, mesh = {Acyl-Butyrolactones/*metabolism ; Bacteria/genetics ; *Bacterial Physiological Phenomena ; *Biological Evolution ; Industrial Microbiology ; Pseudomonas aeruginosa/genetics/metabolism ; *Quorum Sensing ; }, abstract = {Quorum sensing (QS) is a widespread process in bacteria that employs autoinducing chemical signals to coordinate diverse, often cooperative activities such as bioluminescence, biofilm formation, and exoenzyme secretion. Signaling via acyl-homoserine lactones is the paradigm for QS in Proteobacteria and is particularly well understood in the opportunistic pathogen Pseudomonas aeruginosa. Despite thirty years of mechanistic research, empirical studies have only recently addressed the benefits of QS and provided support for the traditional assumptions regarding its social nature and its role in optimizing cell-density-dependent group behaviors. QS-controlled public-goods production has served to investigate principles that explain the evolution and stability of cooperation, including kin selection, pleiotropic constraints, and metabolic prudence. With respect to medical application, appreciating social dynamics is pertinent to understanding the efficacy of QS-inhibiting drugs and the evolution of resistance. Future work will provide additional insight into the foundational assumptions of QS and relate laboratory discoveries to natural ecosystems.}, } @article {pmid23682587, year = {2013}, author = {Langos, D and Kulik, L and Mundry, R and Widdig, A}, title = {The impact of paternity on male-infant association in a primate with low paternity certainty.}, journal = {Molecular ecology}, volume = {22}, number = {13}, pages = {3638-3651}, pmid = {23682587}, issn = {1365-294X}, support = {P40 OD012217/OD/NIH HHS/United States ; P40 RR003640/RR/NCRR NIH HHS/United States ; 8 P40 OD012217-25/OD/NIH HHS/United States ; }, mesh = {Animals ; Female ; Genotype ; Macaca mulatta/*genetics ; Male ; Paternal Behavior/*physiology ; Puerto Rico ; Reproduction/genetics ; Sexual Behavior, Animal/*physiology ; Sexual Maturation/genetics ; }, abstract = {In multimale groups where females mate promiscuously, male-infant associations have rarely been studied. However, recent studies have shown that males selectively support their offspring during agonistic conflicts with other juveniles and that father's presence accelerates offspring maturation. Furthermore, it was shown that males invest in unrelated infants to enhance future mating success with the infant's mother. Hence, infant care might provide fitness gain for males. Here, we investigate male-infant associations in rhesus macaques (Macaca mulatta), a primate with low paternity certainty as females mate with multiple partners and males ensure paternity less efficiently through mate-guarding. We combined behavioural data with genetic paternity analyses of one cohort of the semi-free-ranging population of Cayo Santiago (Puerto Rico) and recorded affiliative and aggressive interactions between focal subjects and adult males from birth to sexual maturation (0-4 years) of focal subjects. Our results revealed that 9.6% of all interactions of focal subjects involved an adult male and 94% of all male-infant interactions were affiliative, indicating the rareness of male-infant aggression. Second and most interestingly, sires were more likely to affiliate with their offspring than nonsires with unrelated infants. This preference was independent of mother's proximity and emphasized during early infancy. Male-infant affiliation rose with infant age and was pronounced between adult males and male rather than female focal subjects. Overall, our results suggest that male-infant affiliation is also an important component in structuring primate societies and affiliation directed towards own offspring presumably represent low-cost paternal care.}, } @article {pmid23681276, year = {2013}, author = {Rimmer, JH and Henley, KY}, title = {Building the crossroad between inpatient/outpatient rehabilitation and lifelong community-based fitness for people with neurologic disability.}, journal = {Journal of neurologic physical therapy : JNPT}, volume = {37}, number = {2}, pages = {72-77}, doi = {10.1097/NPT.0b013e318291bbf6}, pmid = {23681276}, issn = {1557-0584}, mesh = {*Continuity of Patient Care ; *Disabled Persons ; *Health Promotion ; Humans ; Inpatients ; Nervous System Diseases/*rehabilitation ; Outpatients ; *Physical Fitness ; }, abstract = {The length of stay in inpatient and outpatient rehabilitation after an injury or illness has declined in recent years, exposing those with newly acquired neurologic disability to a risk of significant postrehabilitation health decline. Following a short stay in outpatient rehabilitation, individuals with neurologic disability have few, if any, options to continue their physical recovery after discharge, thus further increasing their risk for functional decline and secondary conditions. Professionals who work in community-based fitness facilities have the potential to assist therapists in extending the recovery process and preventing this decline. The focus of this article was to address a conceptual framework for better understanding how rehabilitation and health/fitness professionals can work together to help with this growing need. To that end, the antecedents to and effects of postrehabilitation health decline are discussed, followed by the introduction of a theoretical model illustrating a therapist-to-trainer system that facilitates the use of community-based fitness facilities by individuals with neurologic disabilities to continue their recovery postrehabilitation. Finally, a thorough description of an exemplary existing community-based inclusive fitness program is presented, followed by examples of select disability groups using these programs for continued recovery.Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A45) for more insights from the authors.}, } @article {pmid23675944, year = {2013}, author = {Kuijper, B and Johnstone, RA}, title = {How should parents adjust the size of their young in response to local environmental cues?.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {7}, pages = {1488-1498}, doi = {10.1111/jeb.12156}, pmid = {23675944}, issn = {1420-9101}, mesh = {Adaptation, Psychological ; Animals ; Environment ; Female ; Male ; Models, Biological ; *Models, Theoretical ; Population Dynamics ; Reproduction/*physiology ; }, abstract = {Models of parental investment typically assume that populations are well mixed and homogeneous and have devoted little attention to the impact of spatial variation in the local environment. Here, in a patch-structured model with limited dispersal, we assess to what extent resource-rich and resource-poor mothers should alter the size of their young in response to the local environment in their patch. We show that limited dispersal leads to a correlation between maternal and offspring environments, which favours plastic adjustment of offspring size in response to local survival risk. Strikingly, however, resource-poor mothers are predicted to respond more strongly to local survival risk, whereas resource-rich mothers are predicted to respond less strongly. This lack of sensitivity on the part of resource-rich mothers is favoured because they accrue much of their fitness through dispersing young. By contrast, resource-poor mothers accrue a larger fraction of their fitness through philopatric young and should therefore respond more strongly to local risk. Mothers with more resources gain a larger share of their fitness through dispersing young partly because their fitness in the local patch is constrained by the limited number of local breeding spots. In addition, when resource variation occurs at the patch level, the philopatric offspring of resource-rich mothers face stronger competition from the offspring of other local mothers, who also enjoy abundant resources. The effect of limited local breeding opportunities becomes less pronounced as patch size increases, but the impact of patch-level variation in resources holds up even with many breeders per patch.}, } @article {pmid23669540, year = {2013}, author = {Bowers, EK and Sakaluk, SK and Thompson, CF}, title = {Sibling cooperation influences the age of nest leaving in an altricial bird.}, journal = {The American naturalist}, volume = {181}, number = {6}, pages = {775-786}, doi = {10.1086/670244}, pmid = {23669540}, issn = {1537-5323}, mesh = {Age Factors ; Analysis of Variance ; Animals ; *Cooperative Behavior ; Female ; Genetic Fitness ; Male ; Models, Statistical ; *Nesting Behavior ; Proportional Hazards Models ; *Selection, Genetic ; *Siblings ; *Songbirds ; }, abstract = {In altricial birds, siblings raised within a nest usually leave the nest within hours of each other, despite often differing considerably in age. The youngest members of the brood are typically underdeveloped at this time and less likely than their older siblings to survive outside the nest, yet they risk abandonment if they do not fledge with their older siblings. Nest leaving is usually initiated by the older offspring, which may delay this process to provide more time for their younger siblings to mature, increasing the younger siblings' postfledging survival and their own inclusive fitness. We tested this hypothesis in a population of house wrens Troglodytes aedon and found that broods with broad age spans among siblings had longer nestling periods than broods with narrow age spans and that delayed fledging improves the survival and reproductive prospects of younger siblings, although at a potential cost to future siblings. We also manipulated age spans through cross-fostering and found that older foster nestlings postponed fledging when raised with younger broodmates, as predicted if the age of younger nestlings determines the time of fledging. Our results support kin-selection theory and demonstrate that the exact time of fledging is attributable, in part, to sib-sib interactions.}, } @article {pmid23665207, year = {2013}, author = {McAvity, DM and Bristow, T and Bunker, E and Dreyer, A}, title = {Perception without self-matching in conditional tag based cooperation.}, journal = {Journal of theoretical biology}, volume = {333}, number = {}, pages = {58-67}, doi = {10.1016/j.jtbi.2013.04.027}, pmid = {23665207}, issn = {1095-8541}, mesh = {*Cooperative Behavior ; Humans ; *Models, Biological ; *Self Concept ; }, abstract = {We consider a model for the evolution of cooperation in a population where individuals may have one of a number of different heritable and distinguishable markers or tags. Individuals interact with each of their neighbors on a square lattice by either cooperating by donating some benefit at a cost to themselves or defecting by doing nothing. The decision to cooperate or defect is contingent on each individual's perception of its interacting partner's tag. Unlike in other tag-based models individuals do not compare their own tag to that of their interaction partner. That is, there is no self-matching. When perception is perfect the cooperation rate is substantially higher than in the usual spatial prisoner's dilemma game when the cost of cooperation is high. The enhancement in cooperation is positively correlated with the number of different tags. The more diverse a population is the more cooperative it becomes. When individuals start with an inability to perceive tags the population evolves to a state where individuals gain at least partial perception. With some reproduction mechanisms perfect perception evolves, but with others the ability to perceive tags is imperfect. We find that perception of tags evolves to lower levels when the cost of cooperation is higher.}, } @article {pmid23662923, year = {2013}, author = {Frank, SA}, title = {Natural selection. VII. History and interpretation of kin selection theory.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {6}, pages = {1151-1184}, doi = {10.1111/jeb.12131}, pmid = {23662923}, issn = {1420-9101}, mesh = {*Biological Evolution ; *Selection, Genetic ; }, abstract = {Kin selection theory is a kind of causal analysis. The initial form of kin selection ascribed cause to costs, benefits and genetic relatedness. The theory then slowly developed a deeper and more sophisticated approach to partitioning the causes of social evolution. Controversy followed because causal analysis inevitably attracts opposing views. It is always possible to separate total effects into different component causes. Alternative causal schemes emphasize different aspects of a problem, reflecting the distinct goals, interests and biases of different perspectives. For example, group selection is a particular causal scheme with certain advantages and significant limitations. Ultimately, to use kin selection theory to analyse natural patterns and to understand the history of debates over different approaches, one must follow the underlying history of causal analysis. This article describes the history of kin selection theory, with emphasis on how the causal perspective improved through the study of key patterns of natural history, such as dispersal and sex ratio, and through a unified approach to demographic and social processes. Independent historical developments in the multivariate analysis of quantitative traits merged with the causal analysis of social evolution by kin selection.}, } @article {pmid23637392, year = {2013}, author = {Holland, JG and Guidat, FS and Bourke, AF}, title = {Queen control of a key life-history event in a eusocial insect.}, journal = {Biology letters}, volume = {9}, number = {3}, pages = {20130056}, pmid = {23637392}, issn = {1744-957X}, mesh = {Animals ; Bees/growth & development/*physiology ; *Behavior, Animal ; Female ; *Life Cycle Stages ; }, abstract = {In eusocial insects, inclusive fitness theory predicts potential queen-worker conflict over the timing of events in colony life history. Whether queens or workers control the timing of these events is poorly understood. In the bumble-bee Bombus terrestris, queens exhibit a 'switch point' in which they switch from laying diploid eggs yielding females (workers and new queens) to laying haploid eggs yielding males. By rearing foundress queens whose worker offspring were removed as pupae and sexing their eggs using microsatellite genotyping, we found that queens kept in the complete absence of adult workers still exhibit a switch point. Moreover, the timing of their switch points relative to the start of egg-laying did not differ significantly from that of queens allowed to produce normal colonies. The finding that bumble-bee queens can express the switch point in the absence of workers experimentally demonstrates queen control of a key life-history event in eusocial insects. In addition, we found no evidence that workers affect the timing of the switch point either directly or indirectly via providing cues to queens, suggesting that workers do not fully express their interests in queen-worker conflicts over colony life history.}, } @article {pmid23543424, year = {2013}, author = {Krupp, DB and Sewall, LA and Lalumière, ML and Sheriff, C and Harris, GT}, title = {Psychopathy, adaptation, and disorder.}, journal = {Frontiers in psychology}, volume = {4}, number = {}, pages = {139}, pmid = {23543424}, issn = {1664-1078}, abstract = {In a recent study, we found a negative association between psychopathy and violence against genetic relatives. We interpreted this result as a form of nepotism and argued that it failed to support the hypothesis that psychopathy is a mental disorder, suggesting instead that it supports the hypothesis that psychopathy is an evolved life history strategy. This interpretation and subsequent arguments have been challenged in a number of ways. Here, we identify several misunderstandings regarding the harmful dysfunction definition of mental disorder as it applies to psychopathy and regarding the meaning of nepotism. Furthermore, we examine the evidence provided by our critics that psychopathy is associated with other disorders, and we offer a comment on their alternative model of psychopathy. We conclude that there remains little evidence that psychopathy is the product of dysfunctional mechanisms.}, } @article {pmid23516238, year = {2013}, author = {Refardt, D and Bergmiller, T and Kümmerli, R}, title = {Altruism can evolve when relatedness is low: evidence from bacteria committing suicide upon phage infection.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1759}, pages = {20123035}, pmid = {23516238}, issn = {1471-2954}, mesh = {Altruism ; Bacteriophage T4/physiology ; Coliphages/*physiology ; Escherichia coli/genetics/*physiology/*virology ; Flow Cytometry ; Microbial Interactions ; Prophages/*physiology ; Selection, Genetic ; Viral Nonstructural Proteins/metabolism ; }, abstract = {High relatedness among interacting individuals has generally been considered a precondition for the evolution of altruism. However, kin-selection theory also predicts the evolution of altruism when relatedness is low, as long as the cost of the altruistic act is minor compared with its benefit. Here, we demonstrate evidence for a low-cost altruistic act in bacteria. We investigated Escherichia coli responding to the attack of an obligately lytic phage by committing suicide in order to prevent parasite transmission to nearby relatives. We found that bacterial suicide provides large benefits to survivors at marginal costs to committers. The cost of suicide was low, because infected cells are moribund, rapidly dying upon phage infection, such that no more opportunity for reproduction remains. As a consequence of its marginal cost, host suicide was selectively favoured even when relatedness between committers and survivors approached zero. Altogether, our findings demonstrate that low-cost suicide can evolve with ease, represents an effective host-defence strategy, and seems to be widespread among microbes. Moreover, low-cost suicide might also occur in higher organisms as exemplified by infected social insect workers leaving the colony to die in isolation.}, } @article {pmid23505485, year = {2013}, author = {Costa-Urrutia, P and Sanvito, S and Victoria-Cota, N and Enríquez-Paredes, L and Gendron, D}, title = {Fine-scale population structure of blue whale wintering aggregations in the Gulf of California.}, journal = {PloS one}, volume = {8}, number = {3}, pages = {e58315}, pmid = {23505485}, issn = {1932-6203}, mesh = {*Animal Migration ; Animals ; Balaenoptera/*genetics ; Bayes Theorem ; Bays ; California ; Genetic Variation ; Genetics, Population ; Microsatellite Repeats ; *Seasons ; Spatio-Temporal Analysis ; }, abstract = {Population differentiation in environments without well-defined geographical barriers represents a challenge for wildlife management. Based on a comprehensive database of individual sighting records (1988-2009) of blue whales from the winter/calving Gulf of California, we assessed the fine-scale genetic and spatial structure of the population using individual-based approaches. Skin samples of 187 individuals were analyzed for nine microsatellite loci. A single population with no divergence among years and months and no isolation by distance (Rxy = 0.1-0.001, p>0.05) were found. We ran two bayesian clustering methods using Structure and Geneland softwares in two different ways: 1) a general analysis including all individuals in which a single cluster was identified with both softwares; 2) a specific analysis of females only in which two main clusters (Loreto Bay and northern areas, and San Jose-La Paz Bay area) were revealed by Geneland program. This study provides information indicating that blue whales wintering in the Gulf of California are part of a single population unit and showed a fine-scale structure among females, possibly associated with their high site fidelity, particularly when attending calves. It is likely that the loss of genetic variation is minimized by male mediated gene flow, which may reduce the genetic drift effect. Opportunities for kin selection may also influence calf survival and, in consequence, have a positive impact on population demography in this small and endangered population.}, } @article {pmid23486437, year = {2013}, author = {Wu, JJ and He, QQ and Deng, LL and Wang, SC and Mace, R and Ji, T and Tao, Y}, title = {Communal breeding promotes a matrilineal social system where husband and wife live apart.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1758}, pages = {20130010}, pmid = {23486437}, issn = {1471-2954}, mesh = {Agriculture ; Biological Evolution ; China ; Family Characteristics ; *Family Relations ; Female ; *Genetic Fitness ; Humans ; *Interpersonal Relations ; Male ; Marriage ; Models, Biological ; *Reproduction ; Sibling Relations ; Social Behavior ; }, abstract = {The matrilineal Mosuo of southwest China live in large communal houses where brothers and sisters of three generations live together, and adult males walk to visit their wives only at night; hence males do not reside with their own offspring. This duolocal residence with 'walking' or 'visiting' marriage is described in only a handful of matrilineal peasant societies. Benefits to women of living with matrilineal kin, who cooperate with child-care, are clear. But why any kinship system can evolve where males invest more in their sister's offspring than their own is a puzzle for evolutionary anthropologists. Here, we present a new hypothesis for a matrilineal bias in male investment. We argue that, when household resources are communal, relatedness to the whole household matters more than relatedness to individual offspring. We use an inclusive fitness model to show that the more sisters (and other closely related females) co-reside, the more effort males should spend working on their sister's farm and less on their wife's farm. The model shows that paternity uncertainty may be a cause of lower overall work rates in males, but it is not likely to be the cause of a matrilineal bias. The bias in work effort towards working on their natal farm, and thus the duolocal residence and 'visiting marriage' system, can be understood as maximizing inclusive fitness in circumstances where female kin breed communally.}, } @article {pmid23471407, year = {2013}, author = {Hoogland, JL}, title = {Prairie dogs disperse when all close kin have disappeared.}, journal = {Science (New York, N.Y.)}, volume = {339}, number = {6124}, pages = {1205-1207}, doi = {10.1126/science.1231689}, pmid = {23471407}, issn = {1095-9203}, mesh = {*Animal Distribution ; Animals ; *Competitive Behavior ; Female ; Inbreeding ; Male ; *Reproduction ; Sciuridae/anatomy & histology/*physiology ; *Territoriality ; }, abstract = {Because competition decreases inclusive fitness among kin, Hamilton and May predicted that the presence of nearby kin should induce the dispersal of individuals from the natal territory, independent of pressures to avoid inbreeding. Many studies support this landmark prediction, but research over 31 years with prairie dogs reveals the opposite pattern: Young females are 12.5 times more likely to disperse in the absence of mother and siblings for one species, and 5.5 times more likely for another species. Such striking patterns probably occur because cooperation among kin is more important than competition among kin for young prairie dogs. The inability to cooperate with close kin, due to their absence, prompts a search for a new territory where cooperation might be less crucial for survival and reproduction.}, } @article {pmid23458432, year = {2013}, author = {Preston, SD}, title = {The origins of altruism in offspring care.}, journal = {Psychological bulletin}, volume = {139}, number = {6}, pages = {1305-1341}, doi = {10.1037/a0031755}, pmid = {23458432}, issn = {1939-1455}, mesh = {*Altruism ; Animals ; Animals, Newborn/psychology ; Behavior, Animal/*physiology ; Caregivers/*psychology ; Decision Making/physiology ; Empathy/physiology ; Family/*psychology ; Haplorhini ; Helping Behavior ; Hominidae ; Humans ; Infant ; Infant, Newborn ; Mothers/psychology ; Motivation/physiology ; Rats ; }, abstract = {The current review aims to unify existing views of altruism through an examination of the biological bases of a fundamental form of giving: altruistic responding. Altruistic responding is most salient during heroic acts of helping but is also observed any time one perceives another's distress or need, which in turn motivates one to help at a current cost to the self. Such aid is simple, observable across species, and rooted in the instincts and circuits that evolved to maximize inclusive fitness through the care of helpless offspring. By design, the system already biases aid to both kin and nonkin under conditions that are largely adaptive. These inherent benefits are also buttressed in primates and humans by known, later-arriving benefits to helping in group-living animals. Evidence for the proposed homology between altruistic responding and offspring retrieval is presented through 10 key shared factors. Conceptually, both require (a) participation by nonmothers, (b) motor competence and expertise, (c) an adaptive opponency between avoidance and approach, and a facilitating role of (d) neonatal vulnerability, (e) salient distress, and (f) rewarding close contact. Physiologically, they also share neurohormonal support from (g) oxytocin, (h) the domain-general mesolimbocortical system, (i) the cingulate cortex, and (j) the orbitofrontal cortex. The framework intermixes ultimate and proximate levels of analysis and unifies existing views by assuming that even complex human behaviors reflect ancient mammalian neural systems that evolved to solve key problems in adaptive ways, with far-reaching consequences for even our most venerated human traits.}, } @article {pmid23455897, year = {2013}, author = {Loope, KJ and Seeley, TD and Mattila, HR}, title = {No facultative worker policing in the honey bee (Apis mellifera L.).}, journal = {Die Naturwissenschaften}, volume = {100}, number = {5}, pages = {473-477}, pmid = {23455897}, issn = {1432-1904}, mesh = {Animals ; Bees/*physiology ; Behavior, Animal/*physiology ; Female ; Male ; Sexual Behavior, Animal/physiology ; Social Behavior ; }, abstract = {Kin selection theory predicts that in colonies of social Hymenoptera with multiply mated queens, workers should mutually inhibit ("police") worker reproduction, but that in colonies with singly mated queens, workers should favor rearing workers' sons instead of queens' sons. In line with these predictions, Mattila et al. (Curr Biol 22:2027-2031, 2012) documented increased ovary development among workers in colonies of honey bees with singly mated queens, suggesting that workers can detect and respond adaptively to queen mating frequency and raising the possibility that they facultative police. In a follow-up experiment, we test and reject the hypothesis that workers in single-patriline colonies prefer worker-derived males and are able to reproduce directly; we show that their eggs are policed as strongly as those of workers in colonies with multiply mated queens. Evidently, workers do not respond facultatively to a kin structure that favors relaxed policing and increased direct reproduction. These workers may instead be responding to a poor queen or preparing for possible queen loss.}, } @article {pmid23451032, year = {2013}, author = {Kazem, AJ and Widdig, A}, title = {Visual phenotype matching: cues to paternity are present in rhesus macaque faces.}, journal = {PloS one}, volume = {8}, number = {2}, pages = {e55846}, pmid = {23451032}, issn = {1932-6203}, support = {P40 OD012217/OD/NIH HHS/United States ; 8 P40 OD012217-25/OD/NIH HHS/United States ; }, mesh = {Animals ; Cues ; Face/*physiology ; Female ; Humans ; Macaca mulatta ; Male ; *Paternity ; Phenotype ; }, abstract = {The ability to recognize kin and thus behaviourally discriminate between conspecifics based on genetic relatedness is of importance both in acquiring inclusive fitness benefits and to enable optimal inbreeding. In primates, mechanisms allowing recognition of paternal relatives are of particular interest, given that in these mating systems patrilineal information is unlikely to be available via social familiarity. Humans use visual phenotype matching based on facial features to identify their own and other's close relatives, and recent studies suggest similar abilities may be present in other species. However it is unclear to what extent familial resemblances remain detectable against the background levels of relatedness typically found within demes in the wild - a necessary condition if facial cues are to function in kin recognition under natural conditions. Here, we experimentally investigate whether parent-offspring relationships are discernible in rhesus macaque (Macaca mulatta) faces drawn from a large free-ranging population more representative of the latter scenario, and in which genetic relatedness has been well quantified from pedigrees determined via molecular markers. We used the human visual system as a means of integrating multiple types of facial cue simultaneously, and demonstrate that paternal, as well as maternal, resemblance to both sons and daughters can be detected even by human observers. Experts performed better than participants who lacked previous experience working with nonhuman primates. However the finding that even naïve individuals succeeded at the task underlines the strength of the phenotypic cues present in faces.}, } @article {pmid23436383, year = {2013}, author = {Scott, NM}, title = {Gesture use by chimpanzees (Pan troglodytes): differences between sexes in inter- and intra-sexual interactions.}, journal = {American journal of primatology}, volume = {75}, number = {6}, pages = {555-567}, doi = {10.1002/ajp.22133}, pmid = {23436383}, issn = {1098-2345}, support = {T32 HD007151/HD/NICHD NIH HHS/United States ; }, mesh = {*Animal Communication ; Animals ; Animals, Zoo ; Female ; *Gestures ; Male ; Pan troglodytes/*psychology ; *Sexual Behavior, Animal ; Video Recording ; }, abstract = {Communication and social relationships are two of the most important aspects of primate life, but few studies have focused on linking these aspects in apes. There are some shared social pressures between the two sexes (e.g., kin selection, alliance formation, and protection against attack), but there are also differences (e.g., mate selection, dispersal, and social ranking systems). The aim of this study was to identify the communication strategies of the sexes with respect to their particular communication partner. I hypothesized the sexes use different strategies in their gestural communication based on their different social pressures. Specifically, males should have more positive intra-sexual relationships than females because of high focus on male-male alliance formation and maintaining high social rank, both of which directly affect their mating opportunities and relationships with all other members of the group. On the other hand, females should have more positive inter-sexual relationships due to the abuse they could receive from insubordination to males and because there is less focus on maintaining multiple, positive relationships with other females. Furthermore, because of differences in social pressures, males should have higher incidence of reassurance in same-sex interactions than females because it should be more important for males to mitigate negative interactions. I analyzed the characteristics of the gesture repertoire and frequency of gesture use for each sex in each of four contexts: (1) aggression, (2) submission, (3) greeting, and (4) reassurance. I looked at intra-sexual and inter-sexual interactions, separately. I found that, indeed, males and females utilize different strategies of gestural communication. I also found that females, but not males, have a distinct gesture strategy for communicating with the opposite sex than for the same sex. This study shows there are distinct strategies utilized by the two sexes and these differences may be explained by their differing social pressures.}, } @article {pmid23416223, year = {2013}, author = {Taylor, P}, title = {Inclusive and personal fitness in synergistic evolutionary games on graphs.}, journal = {Journal of theoretical biology}, volume = {325}, number = {}, pages = {76-82}, doi = {10.1016/j.jtbi.2013.02.002}, pmid = {23416223}, issn = {1095-8541}, mesh = {Animals ; *Biological Evolution ; *Game Theory ; Gene Frequency ; Mathematical Concepts ; *Models, Genetic ; Social Behavior ; }, abstract = {I study the evolution of a pair of competing behavioural alleles in a finite graph-structured population when there are non-additive or "synergistic" fitness effects. I begin with the Price equation and extend it to both a personal-fitness and an inclusive-fitness formulation. I thereby obtain an extension of "Hamilton's Rule" to synergistic effects and I calculate and interpret the generalized relatedness coefficients. I present an example of the analysis in a cycle graph with 4 nodes.}, } @article {pmid23382931, year = {2013}, author = {Zukewich, J and Kurella, V and Doebeli, M and Hauert, C}, title = {Consolidating birth-death and death-birth processes in structured populations.}, journal = {PloS one}, volume = {8}, number = {1}, pages = {e54639}, pmid = {23382931}, issn = {1932-6203}, mesh = {Algorithms ; Biological Evolution ; Computer Simulation ; *Game Theory ; *Models, Biological ; Population Dynamics ; Reproduction ; }, abstract = {Network models extend evolutionary game theory to settings with spatial or social structure and have provided key insights on the mechanisms underlying the evolution of cooperation. However, network models have also proven sensitive to seemingly small details of the model architecture. Here we investigate two popular biologically motivated models of evolution in finite populations: Death-Birth (DB) and Birth-Death (BD) processes. In both cases reproduction is proportional to fitness and death is random; the only difference is the order of the two events at each time step. Although superficially similar, under DB cooperation may be favoured in structured populations, while under BD it never is. This is especially troubling as natural populations do not follow a strict one birth then one death regimen (or vice versa); such constraints are introduced to make models more tractable. Whether structure can promote the evolution of cooperation should not hinge on a simplifying assumption. Here, we propose a mixed rule where in each time step DB is used with probability δ and BD is used with probability 1-δ. We derive the conditions for selection favouring cooperation under the mixed rule for all social dilemmas. We find that the only qualitatively different outcome occurs when using just BD (δ = 0). This case admits a natural interpretation in terms of kin competition counterbalancing the effect of kin selection. Finally we show that, for any mixed BD-DB update and under weak selection, cooperation is never inhibited by population structure for any social dilemma, including the Snowdrift Game.}, } @article {pmid23372676, year = {2013}, author = {Pollet, TV and Roberts, SG and Dunbar, RI}, title = {Going that extra mile: individuals travel further to maintain face-to-face contact with highly related kin than with less related kin.}, journal = {PloS one}, volume = {8}, number = {1}, pages = {e53929}, pmid = {23372676}, issn = {1932-6203}, mesh = {Adult ; Altruism ; Child ; Emotions ; Family/*psychology ; Female ; Humans ; *Interpersonal Relations ; Likelihood Functions ; Male ; *Object Attachment ; Surveys and Questionnaires ; Travel/*psychology ; }, abstract = {The theory of inclusive fitness has transformed our understanding of cooperation and altruism. However, the proximate psychological underpinnings of altruism are less well understood, and it has been argued that emotional closeness mediates the relationship between genetic relatedness and altruism. In this study, we use a real-life costly behaviour (travel time) to dissociate the effects of genetic relatedness from emotional closeness. Participants travelled further to see more closely related kin, as compared to more distantly related kin. For distantly related kin, the level of emotional closeness mediated this relationship--when emotional closeness was controlled for, there was no effect of genetic relatedness on travel time. However, participants were willing to travel further to visit parents, children and siblings as compared to more distantly related kin, even when emotional closeness was controlled for. This suggests that the mediating effect of emotional closeness on altruism varies with levels of genetic relatedness.}, } @article {pmid24850977, year = {2013}, author = {Albers, M and Widdig, A}, title = {The Influence of Kinship on Familiar Natal Migrant Rhesus Macaques (Macaca mulatta).}, journal = {International journal of primatology}, volume = {34}, number = {1}, pages = {99-114}, pmid = {24850977}, issn = {0164-0291}, support = {P40 OD012217/OD/NIH HHS/United States ; }, abstract = {In most primate species, females remain in the natal group with kin while males disperse away from kin around the time of puberty. Philopatric females bias their social behavior toward familiar maternal and paternal kin in several species, but little is known about kin bias in the dispersing sex. Male dispersal is likely to be costly because males encounter an increased risk of predation and death, which might be reduced by dispersing together with kin and/or familiar males (individuals that were born and grew up in same natal group) or into a group containing kin and/or familiar males. Here we studied the influence of kinship on familiar natal migrant rhesus macaques (Macaca mulatta) on Cayo Santiago, Puerto Rico, by combining demographic, behavioral, and genetic data. Our data suggest that kinship influences spatial proximity between recent natal immigrants and males familiar to them. Immigrants were significantly nearer to more closely related familiar males than to more distantly related individuals. Within a familiar subgroup, natal migrants were significantly closer to maternal kin, followed by paternal kin, then non-kin, and finally to males related via both the maternal and paternal line. Spatial proximity between natal immigrants and familiar males did not decrease over time in the new group, suggesting that there is no decline in associations between these individuals within the first months of immigration. Overall, our results might indicate that kinship is important for the dispersing sex, at least during natal dispersal when kin are still available.}, } @article {pmid23347411, year = {2013}, author = {Hatchwell, BJ and Sharp, SP and Beckerman, AP and Meade, J}, title = {Ecological and demographic correlates of helping behaviour in a cooperatively breeding bird.}, journal = {The Journal of animal ecology}, volume = {82}, number = {2}, pages = {486-494}, doi = {10.1111/1365-2656.12017}, pmid = {23347411}, issn = {1365-2656}, mesh = {Animals ; *Behavior, Animal ; *Cooperative Behavior ; *Ecosystem ; Models, Biological ; Passeriformes/*physiology ; Population Dynamics ; Reproduction/*physiology ; Time Factors ; }, abstract = {The evolution of cooperation is a persistent problem for evolutionary biologists. In particular, understanding of the factors that promote the expression of helping behaviour in cooperatively breeding species remains weak, presumably because of the diverse nature of ecological and demographic drivers that promote sociality. In this study, we use data from a long-term study of a facultative cooperative breeder, the long-tailed tit Aegithalos caudatus, to investigate the factors influencing annual variation in helping behaviour. Long-tailed tits exhibit redirected helping in which failed breeders may become helpers, usually at a relative's nest; thus, helping is hypothesised to be associated with causes of nest failure and opportunities to renest or help. We tested predictions regarding the relationship between annual measures of cooperative behaviour and four explanatory variables: nest predation rate, length of the breeding season, population-level relatedness and population density. We found that the degree of helping was determined principally by two factors that constrain successful independent reproduction. First, as predicted, cooperative behaviour peaked at intermediate levels of nest predation, when there are both failed breeders (i.e. potential helpers) and active nests (i.e. potential recipients) available. Second, there were more helpers in shorter breeding seasons when opportunities for renesting by failed breeders are more limited. These are novel drivers of helping behaviour in avian cooperative breeding systems, and this study illustrates the difficulty of identifying common ecological or demographic factors underlying the evolution of such systems.}, } @article {pmid23340259, year = {2013}, author = {Domondon, AT}, title = {A history of altruism focusing on Darwin, Allee and E.O. Wilson.}, journal = {Endeavour}, volume = {37}, number = {2}, pages = {94-103}, doi = {10.1016/j.endeavour.2012.12.001}, pmid = {23340259}, issn = {1873-1929}, mesh = {*Altruism ; *Biological Evolution ; History, 19th Century ; Humans ; Inheritance Patterns ; Male ; Models, Genetic ; Natural History/*history ; *Selection, Genetic ; Social Adjustment ; }, abstract = {The problem of altruism refers to the apparent difficulty in reconciling the existence of altruists, individuals who reduce their own fitness to increase the fitness of others, with natural selection. A historical and philosophical overview of solutions to this apparent contradiction is presented through a close reading of the key texts of Charles Darwin, Warder C. Allee and Edward O. Wilson. Following an analysis of Darwin's explanation for altruism, I examine the ideas of group selection and kin selection advanced by Allee and Wilson, respectively, Attention is also given to the philosophical implications each associated with their respective solutions.}, } @article {pmid23339241, year = {2013}, author = {Boomsma, JJ}, title = {Beyond promiscuity: mate-choice commitments in social breeding.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {368}, number = {1613}, pages = {20120050}, pmid = {23339241}, issn = {1471-2970}, mesh = {Adaptation, Biological/*physiology ; Animals ; *Biological Evolution ; Female ; Fertility/physiology ; Genetic Fitness/*genetics ; Insecta/*physiology ; Male ; Mating Preference, Animal/*physiology ; *Models, Biological ; Sexual Behavior, Animal/*physiology ; Species Specificity ; }, abstract = {Obligate eusociality with distinct caste phenotypes has evolved from strictly monogamous sub-social ancestors in ants, some bees, some wasps and some termites. This implies that no lineage reached the most advanced form of social breeding, unless helpers at the nest gained indirect fitness values via siblings that were identical to direct fitness via offspring. The complete lack of re-mating promiscuity equalizes sex-specific variances in reproductive success. Later, evolutionary developments towards multiple queen-mating retained lifetime commitment between sexual partners, but reduced male variance in reproductive success relative to female's, similar to the most advanced vertebrate cooperative breeders. Here, I (i) discuss some of the unique and highly peculiar mating system adaptations of eusocial insects; (ii) address ambiguities that remained after earlier reviews and extend the monogamy logic to the evolution of soldier castes; (iii) evaluate the evidence for indirect fitness benefits driving the dynamics of (in)vertebrate cooperative breeding, while emphasizing the fundamental differences between obligate eusociality and cooperative breeding; (iv) infer that lifetime commitment is a major driver towards higher levels of organization in bodies, colonies and mutualisms. I argue that evolutionary informative definitions of social systems that separate direct and indirect fitness benefits facilitate transparency when testing inclusive fitness theory.}, } @article {pmid23337317, year = {2013}, author = {Parvinen, K}, title = {Joint evolution of altruistic cooperation and dispersal in a metapopulation of small local populations.}, journal = {Theoretical population biology}, volume = {85}, number = {}, pages = {12-19}, doi = {10.1016/j.tpb.2013.01.003}, pmid = {23337317}, issn = {1096-0325}, mesh = {*Altruism ; Animal Distribution ; Animals ; *Biological Evolution ; *Cooperative Behavior ; Ecology ; Humans ; }, abstract = {We investigate the joint evolution of public goods cooperation and dispersal in a metapopulation model with small local populations. Altruistic cooperation can evolve due to assortment and kin selection, and dispersal can evolve because of demographic stochasticity, catastrophes and kin selection. Metapopulation structures resulting in assortment have been shown to make selection for cooperation possible. But how does dispersal affect cooperation and vice versa, when both are allowed to evolve as continuous traits? We found four qualitatively different evolutionary outcomes. (1) Monomorphic evolution to full defection with positive dispersal. (2) Monomorphic evolution to an evolutionarily stable state with positive cooperation and dispersal. In this case, parameter changes selecting for increased cooperation typically also select for increased dispersal. (3) Evolutionary branching can result in the evolutionarily stable coexistence of defectors and cooperators. Although defectors could be expected to disperse more than cooperators, here we show that the opposite case is also possible: Defectors tend to disperse less than cooperators when the total amount of cooperation in the dimorphic population is low enough. (4) Selection for too low cooperation can cause the extinction of the evolving population. For moderate catastrophe rates dispersal needs to be initially very frequent for evolutionary suicide to occur. Although selection for less dispersal in principle could prevent such evolutionary suicide, in most cases this rescuing effect is not sufficient, because selection in the cooperation trait is typically much stronger. If the catastrophe rate is large enough, a part of the boundary of viability can be evolutionarily attracting with respect to both strategy components, in which case evolutionary suicide is expected from all initial conditions.}, } @article {pmid23331930, year = {2013}, author = {Frank, SA}, title = {Natural selection. VI. Partitioning the information in fitness and characters by path analysis.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {3}, pages = {457-471}, doi = {10.1111/jeb.12066}, pmid = {23331930}, issn = {1420-9101}, mesh = {Alleles ; Animals ; *Evolution, Molecular ; Gene Frequency ; *Genetic Fitness ; Genetics, Population/methods ; Inheritance Patterns ; Models, Genetic ; Phenotype ; Regression Analysis ; *Selection, Genetic ; Social Behavior ; }, abstract = {Three steps aid in the analysis of selection. First, describe phenotypes by their component causes. Components include genes, maternal effects, symbionts and any other predictors of phenotype that are of interest. Second, describe fitness by its component causes, such as an individual's phenotype, its neighbours' phenotypes, resource availability and so on. Third, put the predictors of phenotype and fitness into an exact equation for evolutionary change, providing a complete expression of selection and other evolutionary processes. The complete expression separates the distinct causal roles of the various hypothesized components of phenotypes and fitness. Traditionally, those components are given by the covariance, variance and regression terms of evolutionary models. I show how to interpret those statistical expressions with respect to information theory. The resulting interpretation allows one to read the fundamental equations of selection and evolution as sentences that express how various causes lead to the accumulation of information by selection and the decay of information by other evolutionary processes. The interpretation in terms of information leads to a deeper understanding of selection and heritability, and a clearer sense of how to formulate causal hypotheses about evolutionary process. Kin selection appears as a particular type of causal analysis that partitions social effects into meaningful components.}, } @article {pmid23303542, year = {2013}, author = {Bossan, B and Hammerstein, P and Koehncke, A}, title = {We were all young once: an intragenomic perspective on parent-offspring conflict.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1754}, pages = {20122637}, pmid = {23303542}, issn = {1471-2954}, mesh = {Animals ; *Biological Evolution ; *Conflict, Psychological ; Female ; *Maternal Behavior ; *Models, Genetic ; Mutation ; Selection, Genetic ; }, abstract = {Parent-offspring conflict (POC) describes the evolutionary conflict between offspring and their parents over parental resource allocation. Offspring are expected to demand more resources than their parents are willing to supply because these offspring are more related to their own than to their siblings' offspring. Kin selection acts to limit these divergent interests. Our model departs from previous models by describing POC as an intragenomic conflict between genes determining life-history traits during infancy or parenthood. We explain why a direct fitness approach that measures the total fitness effect during exactly one generation is required to correctly assess POC in interbrood rivalry. We find that incorrect assumptions in previous models led to an overestimation of the scope of POC. Moreover, we show why the degree of monogamy is more important for POC than previously thought. Overall, we demonstrate that a life-history-centred intragenomic approach is necessary to correctly interpret POCs. We further discuss how our work relates to the current debate about the usefulness of inclusive fitness theory.}, } @article {pmid23286336, year = {2013}, author = {Grinsted, L and Bilde, T}, title = {Effects of within-colony competition on body size asymmetries and reproductive skew in a social spider.}, journal = {Journal of evolutionary biology}, volume = {26}, number = {3}, pages = {553-561}, doi = {10.1111/jeb.12072}, pmid = {23286336}, issn = {1420-9101}, mesh = {Adaptation, Physiological ; Animals ; *Body Size ; Competitive Behavior/*physiology ; Feeding Behavior/physiology ; Female ; Linear Models ; Male ; Reproduction ; *Social Behavior ; Species Specificity ; Spiders/*physiology ; Survival Analysis ; Time Factors ; }, abstract = {Reproductive partitioning is a key component of social organization in groups of cooperative organisms. In colonies of permanently social spiders of the genus Stegodyphus less than half of the females reproduce, while all females, including nonreproducers, perform suicidal allo-maternal care. Some theoretical models suggest that reproductive skew is a result of contest competition within colonies, leading to size hierarchies where only the largest females become reproducers. We investigated the effect of competition on within-group body size variation over six months in S. dumicola, by manipulating food level and colony size. We found no evidence that competition leads to increased size asymmetry within colonies, suggesting that contest competition may not be the proximate explanation for reproductive skew. Within-colony body size variation was high already in the juvenile stage, and did not increase over the course of the experiment, suggesting that body size variation is shaped at an early stage. This might facilitate task specialization within colonies and ensure colony-level reproductive output by early allocation of reproductive roles. We suggest that reproductive skew in social spiders may be an adaptation to sociality selected through inclusive fitness benefits of allo-maternal care as well as colony-level benefits maximizing colony survival and production.}, } @article {pmid23282995, year = {2013}, author = {Carter, GG and Wilkinson, GS}, title = {Food sharing in vampire bats: reciprocal help predicts donations more than relatedness or harassment.}, journal = {Proceedings. Biological sciences}, volume = {280}, number = {1753}, pages = {20122573}, pmid = {23282995}, issn = {1471-2954}, mesh = {*Altruism ; Animals ; Chiroptera/genetics/*physiology ; *Cooperative Behavior ; *Feeding Behavior ; Female ; Genotype ; Male ; Microsatellite Repeats ; *Selection, Genetic ; Videotape Recording ; }, abstract = {Common vampire bats often regurgitate food to roost-mates that fail to feed. The original explanation for this costly helping behaviour invoked both direct and indirect fitness benefits. Several authors have since suggested that food sharing is maintained solely by indirect fitness because non-kin food sharing could have resulted from kin recognition errors, indiscriminate altruism within groups, or harassment. To test these alternatives, we examined predictors of food-sharing decisions under controlled conditions of mixed relatedness and equal familiarity. Over a 2 year period, we individually fasted 20 vampire bats (Desmodus rotundus) and induced food sharing on 48 days. Surprisingly, donors initiated food sharing more often than recipients, which is inconsistent with harassment. Food received was the best predictor of food given across dyads, and 8.5 times more important than relatedness. Sixty-four per cent of sharing dyads were unrelated, approaching the 67 per cent expected if nepotism was absent. Consistent with social bonding, the food-sharing network was consistent and correlated with mutual allogrooming. Together with past work, these findings support the hypothesis that food sharing in vampire bats provides mutual direct fitness benefits, and is not explained solely by kin selection or harassment.}, } @article {pmid23270702, year = {2013}, author = {Wakano, JY and Ohtsuki, H and Kobayashi, Y}, title = {A mathematical description of the inclusive fitness theory.}, journal = {Theoretical population biology}, volume = {84}, number = {}, pages = {46-55}, doi = {10.1016/j.tpb.2012.11.007}, pmid = {23270702}, issn = {1096-0325}, mesh = {*Algorithms ; Biological Evolution ; Genetic Fitness/*genetics ; Genetics, Population/statistics & numerical data ; Markov Chains ; *Models, Theoretical ; Plants/genetics ; Selection, Genetic/genetics ; }, abstract = {Recent developments in the inclusive fitness theory have revealed that the direction of evolution can be analytically predicted in a wider class of models than previously thought, such as those models dealing with network structure. This paper aims to provide a mathematical description of the inclusive fitness theory. Specifically, we provide a general framework based on a Markov chain that can implement basic models of inclusive fitness. Our framework is based on the probability distribution of "offspring-to-parent map", from which the key concepts of the theory, such as fitness function, relatedness and inclusive fitness, are derived in a straightforward manner. We prove theorems showing that inclusive fitness always provides a correct prediction on which of two competing genes more frequently appears in the long run in the Markov chain. As an application of the theorems, we prove a general formula of the optimal dispersal rate in the Wright's island model with recurrent mutations. We also show the existence of the critical mutation rate, which does not depend on the number of islands and below which a positive dispersal rate evolves. Our framework can also be applied to lattice or network structured populations.}, } @article {pmid23251487, year = {2012}, author = {Loyau, A and Cornuau, JH and Clobert, J and Danchin, E}, title = {Incestuous sisters: mate preference for brothers over unrelated males in Drosophila melanogaster.}, journal = {PloS one}, volume = {7}, number = {12}, pages = {e51293}, pmid = {23251487}, issn = {1932-6203}, mesh = {Animals ; Drosophila melanogaster/*physiology ; Female ; Male ; *Sexual Behavior, Animal ; }, abstract = {The literature is full of examples of inbreeding avoidance, while recent mathematical models predict that inbreeding tolerance or even inbreeding preference should be expected under several realistic conditions like e.g. polygyny. We investigated male and female mate preferences with respect to relatedness in the fruit fly D. melanogaster. Experiments offered the choice between a first order relative (full-sibling or parent) and an unrelated individual with the same age and mating history. We found that females significantly preferred mating with their brothers, thus supporting inbreeding preference. Moreover, females did not avoid mating with their fathers, and males did not avoid mating with their sisters, thus supporting inbreeding tolerance. Our experiments therefore add empirical evidence for inbreeding preference, which strengthens the prediction that inbreeding tolerance and preference can evolve under specific circumstances through the positive effects on inclusive fitness.}, } @article {pmid23251449, year = {2012}, author = {Hinz, C and Gebhardt, K and Hartmann, AK and Sigman, L and Gerlach, G}, title = {Influence of kinship and MHC class II genotype on visual traits in zebrafish larvae (Danio rerio).}, journal = {PloS one}, volume = {7}, number = {12}, pages = {e51182}, pmid = {23251449}, issn = {1932-6203}, mesh = {Animals ; Base Sequence ; DNA Primers ; Eye Color ; *Genotype ; Histocompatibility Antigens Class II/*genetics ; Larva/*physiology ; Skin Pigmentation ; Vision, Ocular/*genetics ; Zebrafish/*genetics/growth & development ; }, abstract = {Kin recognition can drive kin selection and the evolution of social behaviour. In zebrafish (Danio rerio, Hamilton 1822), kin recognition is based on olfactory and visual imprinting processes. If larvae are exposed to visual and chemical cues of kin at day 5 and 6 post fertilization they will recognize kin throughout life, while exposure to non-kin fails to trigger any recognition. Chemical imprinting signals are transcribed by polymorphic genes of the major histocompatibility complex (MHC) code; however, the underlying mechanism for visual imprinting remains unclear. Here we provide evidence for the existence of family-specific differences in morphometry and pigmentation pattern of six day old zebrafish larvae. While rump, tail and body pigmentation were dependent on relatedness, iris pigmentation and morphometry were also influenced by MHC class II genotype. Our study revealed that the MHC not only influences the chemical signature of individuals, but also their visual appearance.}, } @article {pmid23227237, year = {2012}, author = {Camperio Ciani, A and Pellizzari, E}, title = {Fecundity of paternal and maternal non-parental female relatives of homosexual and heterosexual men.}, journal = {PloS one}, volume = {7}, number = {12}, pages = {e51088}, pmid = {23227237}, issn = {1932-6203}, mesh = {Adult ; Aged ; Aged, 80 and over ; Aging ; *Family ; *Fathers ; Female ; Fertility/*physiology ; *Heterosexuality ; *Homosexuality, Male ; Humans ; Male ; Middle Aged ; *Mothers ; Sample Size ; }, abstract = {A variety of social, developmental, biological and genetic factors influence sexual orientation in males. Thus, several hypotheses have attempted to explain the sustenance of genetic factors that influence male homosexuality, despite decreased fecundity within the homosexuals. Kin selection, the existence of maternal effects and two forms of balancing selection, sexually antagonistic selection and overdominance, have been proposed as compensatory mechanisms for reduced homosexual fecundity. Here, we suggest that the empirical support for kin selection and maternal effects cannot account for the low universal frequency and stability of the distribution of homosexuals. To identify the responsible compensatory mechanism, we analyzed fecundity in 2,100 European female relatives, i.e., aunts and grandmothers, of either homosexual or heterosexual probands who were matched in terms of age, culture and sampling strategy. Female relatives were chosen to avoid the sampling bias of the fraternal birth order effect, which occurs when indirectly sampling mothers though their homosexual sons. We observed that the maternal aunts and grandmothers of homosexual probands were significantly more fecund compared with the maternal aunts and maternal grandmothers of the heterosexual probands. No difference in fecundity was observed in the paternal female lines (grandmothers or aunts) from either of the two proband groups. Moreover, due to the selective increase in maternal female fecundity, the total female fecundity was significantly higher in homosexual than heterosexual probands, thus compensating for the reduced fecundity of homosexuals. Altogether, these data support an X-linked multi-locus sexually antagonistic hypothesis rather than an autosomal multi-locus overdominance hypothesis.}, } @article {pmid23212709, year = {2013}, author = {Gibson, AH}, title = {Edward o. Wilson and the organicist tradition.}, journal = {Journal of the history of biology}, volume = {46}, number = {4}, pages = {599-630}, pmid = {23212709}, issn = {0022-5010}, abstract = {Edward O. Wilson's recent decision to abandon kin selection theory has sent shockwaves throughout the biological sciences. Over the past two years, more than a hundred biologists have signed letters protesting his reversal. Making sense of Wilson's decision and the controversy it has spawned requires familiarity with the historical record. This entails not only examining the conditions under which kin selection theory first emerged, but also the organicist tradition against which it rebelled. In similar fashion, one must not only examine Wilson's long career, but also those thinkers who influenced him most, especially his intellectual grandfather, William Morton Wheeler (1865-1937). Wilson belongs to a long line of organicists, biologists whose research highlighted integration and coordination, many of whom struggled over the exact same biological riddles that have long defined Wilson's career. Drawing inspiration (and sometimes ideas) from these intellectual forebears, Wilson is confident that he has finally identified the origin of the social impulse.}, } @article {pmid23209792, year = {2012}, author = {Antfolk, J and Lieberman, D and Santtila, P}, title = {Fitness costs predict inbreeding aversion irrespective of self-involvement: support for hypotheses derived from evolutionary theory.}, journal = {PloS one}, volume = {7}, number = {11}, pages = {e50613}, pmid = {23209792}, issn = {1932-6203}, mesh = {Adult ; Biological Evolution ; *Consanguinity ; Female ; Humans ; Male ; Sexual Behavior/*physiology ; Young Adult ; }, abstract = {It is expected that in humans, the lowered fitness of inbred offspring has produced a sexual aversion between close relatives. Generally, the strength of this aversion depends on the degree of relatedness between two individuals, with closer relatives inciting greater aversion than more distant relatives. Individuals are also expected to oppose acts of inbreeding that do not include the self, as inbreeding between two individuals posits fitness costs not only to the individuals involved in the sexual act, but also to their biological relatives. Thus, the strength of inbreeding aversion should be predicted by the fitness costs an inbred child posits to a given individual, irrespective of this individual's actual involvement in the sexual act. To test this prediction, we obtained information about the family structures of 663 participants, who reported the number of same-sex siblings, opposite-sex siblings, opposite-sex half siblings and opposite-sex cousins. Each participant was presented with three different types of inbreeding scenarios: 1) Participant descriptions, in which participants themselves were described as having sex with an actual opposite-sex relative (sibling, half sibling, or cousin); 2) Related third-party descriptions, in which participants' actual same-sex siblings were described as having sex with their actual opposite-sex relatives; 3) Unrelated third-party descriptions, in which individuals of the same sex as the participants but unrelated to them were described as having sex with opposite-sex relatives. Participants rated each description on the strength of sexual aversion (i.e., disgust-reaction). We found that unrelated third-party descriptions elicited less disgust than related third-party and participant descriptions. Related third-party and participant descriptions elicited similar levels of disgust suggesting that the strength of inbreeding aversion is predicted by inclusive fitness costs. Further, in the related and unrelated conditions alike, the strength of inbreeding aversion was positively associated with the degree of relatedness between those described in the descriptions.}, } @article {pmid23206136, year = {2012}, author = {Jaffé, R and Garcia-Gonzalez, F and den Boer, SP and Simmons, LW and Baer, B}, title = {Patterns of paternity skew among polyandrous social insects: what can they tell us about the potential for sexual selection?.}, journal = {Evolution; international journal of organic evolution}, volume = {66}, number = {12}, pages = {3778-3788}, doi = {10.1111/j.1558-5646.2012.01721.x}, pmid = {23206136}, issn = {1558-5646}, mesh = {Animals ; Female ; *Hymenoptera ; Male ; Phylogeny ; Regression Analysis ; Selection, Genetic ; *Sexual Behavior, Animal ; }, abstract = {Monogamy results in high genetic relatedness among offspring and thus it is generally assumed to be favored by kin selection. Female multiple mating (polyandry) has nevertheless evolved several times in the social Hymenoptera (ants, bees, and wasps), and a substantial amount of work has been conducted to understand its costs and benefits. Relatedness and inclusive fitness benefits are, however, not only influenced by queen mating frequency but also by paternity skew, which is a quantitative measure of paternity biases among the offspring of polyandrous females. We performed a large-scale phylogenetic analysis of paternity skew across polyandrous social Hymenoptera. We found a general and significant negative association between paternity frequency and paternity skew. High paternity skew, which increases relatedness among colony members and thus maximizes inclusive fitness gains, characterized species with low paternity frequency. However, species with highly polyandrous queens had low paternity skew, with paternity equalized among potential sires. Equal paternity shares among fathers are expected to maximize fitness benefits derived from genetic diversity among offspring. We discuss the potential for postcopulatory sexual selection to influence patterns of paternity in social insects, and suggest that sexual selection may have played a key, yet overlooked role in social evolution.}, } @article {pmid23198727, year = {2012}, author = {Kessler, SE and Scheumann, M and Nash, LT and Zimmermann, E}, title = {Paternal kin recognition in the high frequency / ultrasonic range in a solitary foraging mammal.}, journal = {BMC ecology}, volume = {12}, number = {}, pages = {26}, pmid = {23198727}, issn = {1472-6785}, mesh = {Animals ; Cheirogaleidae/*physiology ; Female ; Male ; Recognition, Psychology ; Social Behavior ; Ultrasonics ; *Vocalization, Animal ; }, abstract = {BACKGROUND: Kin selection is a driving force in the evolution of mammalian social complexity. Recognition of paternal kin using vocalizations occurs in taxa with cohesive, complex social groups. This is the first investigation of paternal kin recognition via vocalizations in a small-brained, solitary foraging mammal, the grey mouse lemur (Microcebus murinus), a frequent model for ancestral primates. We analyzed the high frequency/ultrasonic male advertisement (courtship) call and alarm call.

RESULTS: Multi-parametric analyses of the calls' acoustic parameters and discriminant function analyses showed that advertisement calls, but not alarm calls, contain patrilineal signatures. Playback experiments controlling for familiarity showed that females paid more attention to advertisement calls from unrelated males than from their fathers. Reactions to alarm calls from unrelated males and fathers did not differ.

CONCLUSIONS: 1) Findings provide the first evidence of paternal kin recognition via vocalizations in a small-brained, solitarily foraging mammal. 2) High predation, small body size, and dispersed social systems may select for acoustic paternal kin recognition in the high frequency/ultrasonic ranges, thus limiting risks of inbreeding and eavesdropping by predators or conspecific competitors. 3) Paternal kin recognition via vocalizations in mammals is not dependent upon a large brain and high social complexity, but may already have been an integral part of the dispersed social networks from which more complex, kin-based sociality emerged.}, } @article {pmid23195920, year = {2013}, author = {Archetti, M}, title = {Evolution of polygamous marriage by maximization of inclusive fitness.}, journal = {Journal of theoretical biology}, volume = {319}, number = {}, pages = {134-143}, doi = {10.1016/j.jtbi.2012.11.017}, pmid = {23195920}, issn = {1095-8541}, mesh = {Female ; Humans ; Male ; *Marriage ; *Models, Theoretical ; }, abstract = {The majority of human societies practice polygynous marriage, in line with the typical mating pattern found in mammals. Polygyny in humans is often associated with the transfer of wealth to a male's sister's offspring, and it has been suggested that this "mother's brother phenomenon" is adaptive when paternity confidence is low. Polyandry, on the other hand, while virtually unknown in mammals, is practiced by a few human societies, and it has been suggested that this is adaptive if the co-husbands are genetically related. The evolution of human marriage strategies, therefore, can be studied in the framework of kin selection and game theory, as strategic transmission of wealth by males and strategic paternity allocation by females can evolve to maximize inclusive fitness. Here I analyse the stability of polygynous and polyandrous marriage using a game theoretical model previously developed to study monogamy. I show that the "mother's brother phenomenon" depends on the degree of resource depletion through division, whereas the paternity threshold commonly discussed in the anthropological literature is largely irrelevant. Resource depletion through division is also the major determinant of the stability of polyandry, whereas relatedness between co-husbands is not essential. Finally, I show that when females control the transfer of their own resources, monogamy is stable under more general conditions than previously believed.}, } @article {pmid23182969, year = {2012}, author = {Gesselman, AN and Webster, GD}, title = {Inclusive fitness affects both prosocial and antisocial behavior: target gender and insult domain moderate the link between genetic relatedness and aggression.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {10}, number = {4}, pages = {750-761}, pmid = {23182969}, issn = {1474-7049}, mesh = {Adolescent ; Adult ; Aggression/*psychology ; *Family Relations ; Female ; Humans ; *Interpersonal Relations ; Male ; Middle Aged ; Young Adult ; }, abstract = {Although prior research has examined the relationship between genetic relatedness and helping behavior (Burnstein, Crandall, and Kitayama, 1994), less is known about its role in aggressive responses to insults (Fitzgerald and Ketterer, 2011). Drawing on inclusive fitness theory (Hamilton, 1964) and the Kinship, Acceptance, and Rejection Model of Altruism and Aggression (KARMAA; Webster, 2008; Webster et al., 2012), we designed a 2 (participant gender) × 2 (target gender) × 2 (insult: status vs. reproductive) × 3 (relatedness: stranger vs. cousin vs. sibling) between-person experiment in which 489 participants (a) read vignettes in which a stranger, cousin, or sibling was insulted and (b) reported their emotional reaction and retaliation likelihood (six-item α = .91) in response to the insult. Consistent with theory and prior research, men were significantly more aggressive than women, and people were significantly more aggressive responding to insults against kin than non-kin. These findings support theoretically-derived, dynamic, and domain-specific links among insults, gender, relatedness, and aggression.}, } @article {pmid23179098, year = {2012}, author = {Chernenko, A and Holman, L and Helanterä, H and Sundström, L}, title = {Cuticular chemistry of males and females in the ant Formica fusca.}, journal = {Journal of chemical ecology}, volume = {38}, number = {12}, pages = {1474-1482}, pmid = {23179098}, issn = {1573-1561}, mesh = {Animals ; Ants/*chemistry ; Chromatography, Gas ; Discriminant Analysis ; Female ; Hydrocarbons/*analysis ; Male ; Principal Component Analysis ; }, abstract = {Communication between organisms involves visual, auditory, and olfactory pathways. In solitary insects, chemical recognition cues are influenced mainly by selection regimes related to species recognition and sexual selection. In social insects, chemical recognition cues have an additional role in mediating recognition of society members and, thereby, allowing kin selection to operate. Here, we examined whether cuticular hydrocarbon profiles are sex-specific and whether males and young queens of the ant Formica fusca have colony-specific profiles. We also investigated whether there is a relationship between genetic relatedness and chemical diversity within colonies. We demonstrated that female and male sexuals do not have unique sex-specific compounds, but that there are quantitative chemical differences between the sexes. Out of the 51 cuticular hydrocarbon compounds identified, 10 showed a significant quantitative difference between males and females. We also showed that both males and females have a significant colony-specific component in their profiles. Finally, we found a negative correlation between within-colony relatedness and within-colony chemical diversity of branched, but not linear compounds. This suggests that colonies with multiple matri- or patrilines also have a significantly greater chemical diversity.}, } @article {pmid23094799, year = {2012}, author = {Seppä, P and Johansson, H and Gyllenstrand, N and Pálsson, S and Pamilo, P}, title = {Mosaic structure of native ant supercolonies.}, journal = {Molecular ecology}, volume = {21}, number = {23}, pages = {5880-5891}, doi = {10.1111/mec.12070}, pmid = {23094799}, issn = {1365-294X}, mesh = {Animals ; Ants/*genetics ; Bayes Theorem ; DNA, Mitochondrial ; Finland ; *Genetic Variation ; *Genetics, Population ; Haplotypes ; Models, Genetic ; Sweden ; }, abstract = {According to the inclusive fitness theory, some degree of positive relatedness is required for the evolution and maintenance of altruism. However, ant colonies are sometimes large interconnected networks of nests, which are genetically homogenous entities, causing a putative problem for the theory. We studied spatial structure and genetic relatedness in two supercolonies of the ant Formica exsecta, using nuclear and mitochondrial markers. We show that there may be multiple pathways to supercolonial social organization leading to different spatial genetic structures. One supercolony formed a genetically homogenous population dominated by a single mtDNA haplotype, as expected if founded by a small number of colonizers, followed by nest propagation by budding and domination of the habitat patch. The other supercolony had several haplotypes, and the spatial genetic structure was a mosaic of nuclear and mitochondrial clusters. Genetic diversity probably originated from long-range dispersal, and the mosaic population structure is likely a result of stochastic short-range dispersal of individuals. Such a mosaic spatial structure is apparently discordant with the current knowledge about the integrity of ant colonies. Relatedness was low in both populations when estimated among nestmates, but increased significantly when estimated among individuals sharing the same genetic cluster or haplogroup. The latter association indicates the important historical role of queen dispersal in the determination of the spatial genetic structure.}, } @article {pmid23093096, year = {2012}, author = {Grinsted, L and Agnarsson, I and Bilde, T}, title = {Subsocial behaviour and brood adoption in mixed-species colonies of two theridiid spiders.}, journal = {Die Naturwissenschaften}, volume = {99}, number = {12}, pages = {1021-1030}, pmid = {23093096}, issn = {1432-1904}, mesh = {Aggression ; Animals ; Behavior, Animal/*physiology ; DNA Barcoding, Taxonomic ; Electron Transport Complex IV/genetics ; Female ; Indonesia ; Male ; Phylogeny ; RNA, Ribosomal, 28S/genetics ; Sex Ratio ; *Social Behavior ; Species Specificity ; Spiders/genetics/*physiology ; }, abstract = {Cooperation and group living often evolves through kin selection. However, associations between unrelated organisms, such as different species, can evolve if both parties benefit from the interaction. Group living is rare in spiders, but occurs in cooperative, permanently social spiders, as well as in territorial, colonial spiders. Mixed species spider colonies, involving closely related species, have rarely been documented. We examined social interactions in newly discovered mixed-species colonies of theridiid spiders on Bali, Indonesia. Our aim was to test the degree of intra- and interspecific tolerance, aggression and cooperation through behavioural experiments and examine the potential for adoption of foreign brood. Morphological and genetic analyses confirmed that colonies consisted of two related species Chikunia nigra (O.P. Cambridge, 1880) new combination (previously Chrysso nigra) and a yet undescribed Chikunia sp. Females defended territories and did not engage in cooperative prey capture, but interestingly, both species seemed to provide extended maternal care of young and indiscriminate care for foreign brood. Future studies may reveal whether these species adopt only intra-specific young, or also inter-specifically. We classify both Chikunia species subsocial and intra- and interspecifically colonial, and discuss the evolutionary significance of a system where one or both species may potentially benefit from mutual tolerance and brood adoption.}, } @article {pmid23075837, year = {2012}, author = {Fortunato, L}, title = {The evolution of matrilineal kinship organization.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1749}, pages = {4939-4945}, pmid = {23075837}, issn = {1471-2954}, mesh = {*Biological Evolution ; *Family Characteristics ; Female ; Game Theory ; Humans ; Male ; *Marriage ; Models, Biological ; Models, Theoretical ; *Sexual Behavior ; Socioeconomic Factors ; }, abstract = {Matrilineal kinship organization is a human social system that emphasizes interactions between matrilineal kin, i.e. individuals related only through females. The 'matrilineal puzzle' refers to the potential for tension characteristic of this social system, owing to the conflict between the interests and responsibilities of men in their roles as brother/uncle versus husband/father. From an evolutionary perspective, matrilineal kinship organization is puzzling when it diverts investment of resources from the individuals who provide the potentially highest reproductive returns. I use a game-theoretic framework to investigate a particular form of matrilineal inheritance--the transfer of property from a maternal uncle to a sororal nephew. The analysis reveals two mechanisms that may make this strategy a stable evolutionary outcome. First, a polygynous male has multiple wives, and hence multiple brothers-in-law; with matrilineal inheritance, each additional brother-in-law may transfer resources to the male's wife's offspring, thus potentially contributing to the male's inclusive fitness. Second, the husband of a polyandrous female is effectively 'sharing' paternity with other men; depending on the number of husbands, he may be better off investing in his sister's offspring. I conclude by discussing how these results address the challenges posed by the occurrence of matrilineal kinship organization.}, } @article {pmid23049791, year = {2012}, author = {Seppä, P and Queller, DC and Strassmann, JE}, title = {Why wasp foundresses change nests: relatedness, dominance, and nest quality.}, journal = {PloS one}, volume = {7}, number = {9}, pages = {e45386}, pmid = {23049791}, issn = {1932-6203}, mesh = {Animal Communication ; Animals ; *Choice Behavior ; Competitive Behavior/*physiology ; Cooperative Behavior ; Female ; Genetic Fitness/*physiology ; Homing Behavior ; Microsatellite Repeats ; Nesting Behavior/*physiology ; Reproduction/*physiology ; Seasons ; Sexual Behavior, Animal ; Social Behavior ; Wasps/*physiology ; }, abstract = {The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive) fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters.}, } @article {pmid23029158, year = {2012}, author = {File, AL and Klironomos, J and Maherali, H and Dudley, SA}, title = {Plant kin recognition enhances abundance of symbiotic microbial partner.}, journal = {PloS one}, volume = {7}, number = {9}, pages = {e45648}, pmid = {23029158}, issn = {1932-6203}, mesh = {Mycorrhizae/*physiology ; *Plant Physiological Phenomena ; Plant Roots/microbiology ; Plants/*microbiology ; *Symbiosis ; }, abstract = {BACKGROUND: The stability of cooperative interactions among different species can be compromised by cheating. In the plant-mycorrhizal fungi symbiosis, a single mycorrhizal network may interact with many plants, providing the opportunity for individual plants to cheat by obtaining nutrients from the fungi without donating carbon. Here we determine whether kin selection may favour plant investment in the mycorrhizal network, reducing the incentive to cheat when relatives interact with a single network.

We show that mycorrhizal network size and root colonization were greater when Ambrosia artemisiifolia L. was grown with siblings compared to strangers. Soil fungal abundance was positively correlated with group leaf nitrogen, and increased root colonization was associated with a reduced number of pathogen-induced root lesions, indicating greater benefit to plants grown with siblings.

CONCLUSIONS/SIGNIFICANCE: Plants can benefit their relatives through investment in mycorrhizal fungi, and kin selection in plants could promote the persistence of the mycorrhizal symbiosis.}, } @article {pmid22984064, year = {2012}, author = {Foster, EA and Franks, DW and Mazzi, S and Darden, SK and Balcomb, KC and Ford, JK and Croft, DP}, title = {Adaptive prolonged postreproductive life span in killer whales.}, journal = {Science (New York, N.Y.)}, volume = {337}, number = {6100}, pages = {1313}, doi = {10.1126/science.1224198}, pmid = {22984064}, issn = {1095-9203}, support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Female ; *Longevity ; Male ; Proportional Hazards Models ; *Reproduction ; Whale, Killer/*physiology ; }, abstract = {Prolonged life after reproduction is difficult to explain evolutionarily unless it arises as a physiological side effect of increased longevity or it benefits related individuals (i.e., increases inclusive fitness). There is little evidence that postreproductive life spans are adaptive in nonhuman animals. By using multigenerational records for two killer whale (Orcinus orca) populations in which females can live for decades after their final parturition, we show that postreproductive mothers increase the survival of offspring, particularly their older male offspring. This finding may explain why female killer whales have evolved the longest postreproductive life span of all nonhuman animals.}, } @article {pmid22977147, year = {2012}, author = {Taylor, P and Maciejewski, W}, title = {An inclusive fitness analysis of synergistic interactions in structured populations.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1747}, pages = {4596-4603}, pmid = {22977147}, issn = {1471-2954}, mesh = {Animals ; *Behavior, Animal ; Columbidae/physiology ; Game Theory ; Gene Frequency ; Hawks/physiology ; *Models, Theoretical ; *Social Behavior ; }, abstract = {We study the evolution of a pair of competing behavioural alleles in a structured population when there are non-additive or 'synergistic' fitness effects. Under a form of weak selection and with a simple symmetry condition between a pair of competing alleles, Tarnita et al. provide a surprisingly simple condition for one allele to dominate the other. Their condition can be obtained from an analysis of a corresponding simpler model in which fitness effects are additive. Their result uses an average measure of selective advantage where the average is taken over the long-term--that is, over all possible allele frequencies--and this precludes consideration of any frequency dependence the allelic fitness might exhibit. However, in a considerable body of work with non-additive fitness effects--for example, hawk-dove and prisoner's dilemma games--frequency dependence plays an essential role in the establishment of conditions for a stable allele-frequency equilibrium. Here, we present a frequency-dependent generalization of their result that provides an expression for allelic fitness at any given allele frequency p. We use an inclusive fitness approach and provide two examples for an infinite structured population. We illustrate our results with an analysis of the hawk-dove game.}, } @article {pmid22973244, year = {2012}, author = {Krupp, DB and Sewall, LA and Lalumière, ML and Sheriff, C and Harris, GT}, title = {Nepotistic patterns of violent psychopathy: evidence for adaptation?.}, journal = {Frontiers in psychology}, volume = {3}, number = {}, pages = {305}, pmid = {22973244}, issn = {1664-1078}, abstract = {Psychopaths routinely disregard social norms by engaging in selfish, antisocial, often violent behavior. Commonly characterized as mentally disordered, recent evidence suggests that psychopaths are executing a well-functioning, if unscrupulous strategy that historically increased reproductive success at the expense of others. Natural selection ought to have favored strategies that spared close kin from harm, however, because actions affecting the fitness of genetic relatives contribute to an individual's inclusive fitness. Conversely, there is evidence that mental disorders can disrupt psychological mechanisms designed to protect relatives. Thus, mental disorder and adaptation accounts of psychopathy generate opposing hypotheses: psychopathy should be associated with an increase in the victimization of kin in the former account but not in the latter. Contrary to the mental disorder hypothesis, we show here in a sample of 289 violent offenders that variation in psychopathy predicts a decrease in the genetic relatedness of victims to offenders; that is, psychopathy predicts an increased likelihood of harming non-relatives. Because nepotistic inhibition in violence may be caused by dispersal or kin discrimination, we examined the effects of psychopathy on (1) the dispersal of offenders and their kin and (2) sexual assault frequency (as a window on kin discrimination). Although psychopathy was negatively associated with coresidence with kin and positively associated with the commission of sexual assault, it remained negatively associated with the genetic relatedness of victims to offenders after removing cases of offenders who had coresided with kin and cases of sexual assault from the analyses. These results stand in contrast to models positing psychopathy as a pathology, and provide support for the hypothesis that psychopathy reflects an evolutionary strategy largely favoring the exploitation of non-relatives.}, } @article {pmid22913671, year = {2012}, author = {Lahdenperä, M and Gillespie, DOS and Lummaa, V and Russell, AF}, title = {Severe intergenerational reproductive conflict and the evolution of menopause.}, journal = {Ecology letters}, volume = {15}, number = {11}, pages = {1283-1290}, doi = {10.1111/j.1461-0248.2012.01851.x}, pmid = {22913671}, issn = {1461-0248}, mesh = {Adolescent ; Adult ; *Biological Evolution ; Death ; Female ; Finland ; Genetic Fitness ; Humans ; *Intergenerational Relations ; Menopause/*physiology ; Middle Aged ; Models, Theoretical ; Parturition ; *Reproduction ; Risk ; Selection, Genetic ; Survival ; Young Adult ; }, abstract = {Human menopause is ubiquitous among women and is uninfluenced by modernity. In addition, it remains an evolutionary puzzle: studies have largely failed to account for diminishing selection on reproduction beyond 50 years. Using a 200-year dataset on pre-industrial Finns, we show that an important component is between-generation reproductive conflict among unrelated women. Simultaneous reproduction by successive generations of in-laws was associated with declines in offspring survivorship of up to 66%. An inclusive fitness model revealed that incorporation of the fitness consequences of simultaneous intergenerational reproduction between in-laws, with those of grandmothering and risks of dying in childbirth, were sufficient to generate selection against continued reproduction beyond 51 years. Decomposition of model estimates suggested that the former two were most influential in generating selection against continued reproduction. We propose that menopause evolved, in part, because of age-specific increases in opportunities for intergenerational cooperation and reproductive competition under ecological scarcity.}, } @article {pmid22911845, year = {2012}, author = {Goropashnaya, AV and Fedorov, VB and Seifert, B and Pamilo, P}, title = {Phylogenetic relationships of Palaearctic Formica species (Hymenoptera, Formicidae) based on mitochondrial cytochrome B sequences.}, journal = {PloS one}, volume = {7}, number = {7}, pages = {e41697}, pmid = {22911845}, issn = {1932-6203}, mesh = {Animals ; Ants/*genetics ; Base Sequence ; Cytochromes b/*genetics ; DNA, Mitochondrial/*genetics ; Evolution, Molecular ; Genetic Variation ; Haplotypes/genetics ; Likelihood Functions ; Molecular Sequence Data ; *Paleontology ; *Phylogeny ; Species Specificity ; }, abstract = {Ants of genus Formica demonstrate variation in social organization and represent model species for ecological, behavioral, evolutionary studies and testing theoretical implications of the kin selection theory. Subgeneric division of the Formica ants based on morphology has been questioned and remained unclear after an allozyme study on genetic differentiation between 13 species representing all subgenera was conducted. In the present study, the phylogenetic relationships within the genus were examined using mitochondrial DNA sequences of the cytochrome b and a part of the NADH dehydrogenase subunit 6. All 23 Formica species sampled in the Palaearctic clustered according to the subgeneric affiliation except F. uralensis that formed a separate phylogenetic group. Unlike Coptoformica and Formica s. str., the subgenus Serviformica did not form a tight cluster but more likely consisted of a few small clades. The genetic distances between the subgenera were around 10%, implying approximate divergence time of 5 Myr if we used the conventional insect divergence rate of 2% per Myr. Within-subgenus divergence estimates were 6.69% in Serviformica, 3.61% in Coptoformica, 1.18% in Formica s. str., which supported our previous results on relatively rapid speciation in the latter subgenus. The phylogeny inferred from DNA sequences provides a necessary framework against which the evolution of social traits can be compared. We discuss implications of inferred phylogeny for the evolution of social traits.}, } @article {pmid22860635, year = {2013}, author = {Abild, ML and VanderLaan, DP and Vasey, PL}, title = {No evidence for treating friends' children like kin in Canadian androphilic men.}, journal = {Journal of sex research}, volume = {50}, number = {7}, pages = {697-703}, doi = {10.1080/00224499.2012.681404}, pmid = {22860635}, issn = {1559-8519}, mesh = {Adult ; Canada ; Child ; Child Rearing/psychology ; Cross-Cultural Comparison ; Family/*psychology ; Female ; Friends/*psychology ; Homosexuality, Male/*psychology ; Humans ; Male ; Sexuality/*psychology ; }, abstract = {Given that same-sex sexual orientation is associated with lower reproductive success, how have genes associated with male androphilia (i.e., male sexual attraction/arousal to adult men) persisted over evolutionary time? The Kin Selection Hypothesis proposes that by directing valuable resources toward kin, androphilic men may enhance their indirect fitness and thereby offset the fitness costs of not reproducing directly. Support for this hypothesis has been garnered from studies conducted in Samoa, but not from studies of "gay" men in industrialized cultures (i.e., Canada, Japan, United Kingdom, and the United States). This cross-cultural difference may be due to relatively greater geographic and familial disconnect experienced by androphilic "gay" men in industrialized cultures. This article reasons that in more industrialized settings, friends' children may serve as non-adaptive proxies for nieces and nephews. Hence, it was predicted that Canadian androphilic men would exhibit elevated altruistic tendencies toward their friends' children compared with gynephilic men and androphilic women. This prediction was not supported. However, in line with previous research, the results indicated that androphilic women are more likely to behave altruistically toward friends' children compared to gynephilic men. Other possible explanations for the existing cross-cultural discrepancy in altruistic tendencies toward nieces and nephews are discussed.}, } @article {pmid22837829, year = {2012}, author = {Asaduzzaman, SM and Wild, G}, title = {The evolution of dispersal conditioned on migration status.}, journal = {Ecology and evolution}, volume = {2}, number = {4}, pages = {822-843}, pmid = {22837829}, issn = {2045-7758}, abstract = {We consider a model for the evolution of dispersal of offspring. Dispersal is treated as a parental trait that is expressed conditional upon a parent's own "migration status," that is, whether a parent, itself, is native or nonnative to the area in which it breeds. We compare the evolution of this kind of conditional dispersal to the evolution of unconditional dispersal, in order to determine the extent to which the former changes predictions about population-wide levels of dispersal. We use numerical simulations of an inclusive-fitness model, and individual-based simulations to predict population-average dispersal rates for the case in which dispersal based on migration status occurs. When our model predictions are compared to predictions that neglect conditional dispersal, observed differences between rates are only slight, and never exceed 0.06. While the effect of dispersal conditioned upon migration status could be detected in a carefully designed experiment, we argue that less-than-ideal experimental conditions, and factors such as dispersal conditioned on sex are likely to play a larger role that the type of conditional dispersal studied here.}, } @article {pmid22817537, year = {2012}, author = {Markov, AV}, title = {Can kin selection facilitate the evolution of the genetic program of senescence?.}, journal = {Biochemistry. Biokhimiia}, volume = {77}, number = {7}, pages = {733-741}, doi = {10.1134/S0006297912070061}, pmid = {22817537}, issn = {1608-3040}, mesh = {Aging/*genetics ; *Biological Evolution ; Competitive Behavior ; *Computer Simulation ; Genetics, Population ; Models, Genetic ; *Selection, Genetic ; }, abstract = {The theory of adaptive senescence, or phenoptosis ("altruistic suicide" of the organism), implies that mutations enhancing mortality growth with age ("senescence genes") can be favored by selection under some circumstances, although the nature of these circumstances and the frequency of their occurrence are not clear. Here I demonstrate by means of computer simulation that senescence genes can spread in the population's gene pool via the mechanism of kin selection if two conditions are met. First, the population must have high viscosity (low intermixing), which provides positive correlation between spatial proximity of individuals and their relatedness, an important precondition for kin selection. Second, prior to acquisition of the senescence genes, there must be a sufficiently fast decline in the reproductive potential with age, while viability should decrease slower or remain constant. These conditions are probably met in some territorial and social species with severe competition for social rank and mating partners.}, } @article {pmid22787025, year = {2012}, author = {Browning, LE and Patrick, SC and Rollins, LA and Griffith, SC and Russell, AF}, title = {Kin selection, not group augmentation, predicts helping in an obligate cooperatively breeding bird.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1743}, pages = {3861-3869}, pmid = {22787025}, issn = {1471-2954}, mesh = {Animals ; *Cooperative Behavior ; New South Wales ; *Reproduction ; Seasons ; *Selection, Genetic ; Songbirds/*physiology ; }, abstract = {Kin selection theory has been the central model for understanding the evolution of cooperative breeding, where non-breeders help bear the cost of rearing young. Recently, the dominance of this idea has been questioned; particularly in obligate cooperative breeders where breeding without help is uncommon and seldom successful. In such systems, the direct benefits gained through augmenting current group size have been hypothesized to provide a tractable alternative (or addition) to kin selection. However, clear empirical tests of the opposing predictions are lacking. Here, we provide convincing evidence to suggest that kin selection and not group augmentation accounts for decisions of whether, where and how often to help in an obligate cooperative breeder, the chestnut-crowned babbler (Pomatostomus ruficeps). We found no evidence that group members base helping decisions on the size of breeding units available in their social group, despite both correlational and experimental data showing substantial variation in the degree to which helpers affect productivity in units of different size. By contrast, 98 per cent of group members with kin present helped, 100 per cent directed their care towards the most related brood in the social group, and those rearing half/full-sibs helped approximately three times harder than those rearing less/non-related broods. We conclude that kin selection plays a central role in the maintenance of cooperative breeding in this species, despite the apparent importance of living in large groups.}, } @article {pmid22787022, year = {2012}, author = {Rankin, DJ and Turner, LA and Heinemann, JA and Brown, SP}, title = {The coevolution of toxin and antitoxin genes drives the dynamics of bacterial addiction complexes and intragenomic conflict.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1743}, pages = {3706-3715}, pmid = {22787022}, issn = {1471-2954}, support = {095831//Wellcome Trust/United Kingdom ; 082273/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Antitoxins/*genetics/metabolism ; Bacteria/*genetics/metabolism ; Bacterial Toxins/antagonists & inhibitors/*genetics/metabolism ; Cell Death ; Chromosomes, Bacterial/*genetics/physiology ; *Evolution, Molecular ; Genetic Fitness ; Models, Biological ; Plasmids/*genetics/physiology ; }, abstract = {Bacterial genomes commonly contain 'addiction' gene complexes that code for both a toxin and a corresponding antitoxin. As long as both genes are expressed, cells carrying the complex can remain healthy. However, loss of the complex (including segregational loss in daughter cells) can entail death of the cell. We develop a theoretical model to explore a number of evolutionary puzzles posed by toxin-antitoxin (TA) population biology. We first extend earlier results demonstrating that TA complexes can spread on plasmids, as an adaptation to plasmid competition in spatially structured environments, and highlight the role of kin selection. We then considered the emergence of TA complexes on plasmids from previously unlinked toxin and antitoxin genes. We find that one of these traits must offer at least initially a direct advantage in some but not all environments encountered by the evolving plasmid population. Finally, our study predicts non-transitive 'rock-paper-scissors' dynamics to be a feature of intragenomic conflict mediated by TA complexes. Intragenomic conflict could be sufficient to select deleterious genes on chromosomes and helps to explain the previously perplexing observation that many TA genes are found on bacterial chromosomes.}, } @article {pmid22777019, year = {2012}, author = {Pizzari, T and Gardner, A}, title = {The sociobiology of sex: inclusive fitness consequences of inter-sexual interactions.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {367}, number = {1600}, pages = {2314-2323}, pmid = {22777019}, issn = {1471-2970}, mesh = {Altruism ; Animals ; Competitive Behavior/*physiology ; *Conflict, Psychological ; Cooperative Behavior ; Female ; Fertility ; *Genetic Fitness ; *Interpersonal Relations ; Male ; Selection, Genetic ; *Sex ; Sexual Behavior, Animal/physiology ; *Sociobiology ; }, abstract = {The diversity of social interactions between sexual partners has long captivated biologists, and its evolution has been interpreted largely in terms of 'direct fitness' pay-offs to partners and their descendants. Inter-sexual interactions also have 'indirect effects' by affecting the fitness of relatives, with important consequences for inclusive fitness. However, inclusive fitness arguments have received limited consideration in this context, and definitions of 'direct' and 'indirect' fitness effects in this field are often inconsistent with those of inclusive fitness theory. Here, we use a sociobiology approach based on inclusive fitness theory to distinguish between direct and indirect fitness effects. We first consider direct effects: we review how competition leads to sexual conflict, and discuss the conditions under which repression of competition fosters sexual mutualism. We then clarify indirect effects, and show that greenbeard effects, kin recognition and population viscosity can all lead to episodes of indirect selection on sexual interactions creating potential for sexual altruism and spite. We argue that the integration of direct and indirect fitness effects within a sociobiology approach enables us to consider a more diverse spectrum of evolutionary outcomes of sexual interactions, and may help resolving current debates over sexual selection and sexual conflict.}, } @article {pmid22777018, year = {2012}, author = {Rubenstein, DR}, title = {Family feuds: social competition and sexual conflict in complex societies.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {367}, number = {1600}, pages = {2304-2313}, pmid = {22777018}, issn = {1471-2970}, mesh = {Altruism ; Animals ; Biological Evolution ; Choice Behavior ; Competitive Behavior/*physiology ; *Conflict, Psychological ; Cooperative Behavior ; Female ; Male ; Pair Bond ; Reproduction ; Sex Characteristics ; Sexual Behavior, Animal/*physiology ; }, abstract = {Darwin was initially puzzled by the processes that led to ornamentation in males-what he termed sexual selection-and those that led to extreme cooperation and altruism in complex animal societies-what was later termed kin selection. Here, I explore the relationships between sexual and kin selection theory by examining how social competition for reproductive opportunities-particularly in females-and sexual conflict over mating partners are inherent and critical parts of complex altruistic societies. I argue that (i) patterns of reproductive sharing within complex societies can drive levels of social competition and reproductive conflict not only in males but also in females living in social groups, and ultimately the evolution of female traits such as ornaments and armaments; (ii) mating conflict over female choice of sexual partners can influence kin structure within groups and drive the evolution of complex societies; and (iii) patterns of reproductive sharing and conflict among females may also drive the evolution of complex societies by influencing kin structure within groups. Ultimately, complex societies exhibiting altruistic behaviour appear to have only arisen in taxa where social competition over reproductive opportunities and sexual conflict over mating partners were low. Once such societies evolved, there were important selective feedbacks on traits used to regulate and mediate intra-sexual competition over reproductive opportunities, particularly in females.}, } @article {pmid22777013, year = {2012}, author = {Rubenstein, DR}, title = {Sexual and social competition: broadening perspectives by defining female roles.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {367}, number = {1600}, pages = {2248-2252}, pmid = {22777013}, issn = {1471-2970}, mesh = {Animals ; Biological Evolution ; Choice Behavior/*physiology ; Competitive Behavior/*physiology ; Conflict, Psychological ; Female ; Genetic Fitness/physiology ; Interpersonal Relations ; Male ; Mating Preference, Animal/*physiology ; Sex Characteristics ; }, abstract = {Males figured more prominently than females in Darwin's view of sexual selection. He considered female choice of secondary importance to male-male competition as a mechanism to explain the evolution of male ornaments and armaments. Fisher later demonstrated the importance of female choice in driving male trait evolution, but his ideas were largely ignored for decades. As sexual selection came to embrace the notions of parent-offspring and sexual conflict, and experimental tests of female choice showed promise, females began to feature more prominently in the framework of sexual selection theory. Recent debate over this theory has centred around the role of females, not only over the question of choice, but also over female-female competition. Whereas some have called for expanding the sexual selection framework to encompass all forms of female-female competition, others have called for subsuming sexual selection within a broader framework of social selection, or replacing it altogether. Still others have argued for linking sexual selection more clearly to other evolutionary theories such as kin selection. Rather than simply debating terminology, we must take a broader view of the general processes that lead to trait evolution in both sexes by clearly defining the roles that females play in the process, and by focusing on intra- and inter-sexual interactions in males and females.}, } @article {pmid22776671, year = {2012}, author = {Bao, M and Wild, G}, title = {Reproductive skew can provide a net advantage in both conditional and unconditional social interactions.}, journal = {Theoretical population biology}, volume = {82}, number = {3}, pages = {200-208}, doi = {10.1016/j.tpb.2012.06.006}, pmid = {22776671}, issn = {1096-0325}, mesh = {Altruism ; Humans ; *Interpersonal Relations ; }, abstract = {We revisit a model for the evolution of costly social behaviour in the presence of reproductive skew. The model population is structured into groups, and reproductive skew is captured by assuming individuals adopt one of two social roles (dominant/subordinate). Unlike previous work, we adopt an ultimate perspective by tracking a mutant allele over the entire course of an invasion. Our main analysis applies the theory of branching processes, but a parallel analysis using the inclusive-fitness approach is also provided. Our first two results are modifications of known inequalities describing selective advantages for behaviours expressed conditional upon social status. We find that altruistic subordinate individuals are favoured more readily than previously thought; spiteful dominant individuals, however, are favoured less readily. Secondly, we identify the condition under which unconditional altruism (performed by both dominant and subordinate) will be adaptive. Our third main result shows that increasing the strength of selection can also change the range of parameters over which costly social behaviours are favoured. We find that stronger selection makes it relatively easier for subordinate altruism to emerge, but more difficult for dominant spite and unconditional altruism to occur. We discuss the possible implications of our results for human social evolution.}, } @article {pmid22774787, year = {2013}, author = {Archer, J}, title = {Can evolutionary principles explain patterns of family violence?.}, journal = {Psychological bulletin}, volume = {139}, number = {2}, pages = {403-440}, doi = {10.1037/a0029114}, pmid = {22774787}, issn = {1939-1455}, mesh = {Age Factors ; *Biological Evolution ; Domestic Violence/*psychology ; *Family Relations ; Female ; Humans ; Male ; Parents/psychology ; Paternity ; Sexual Partners/psychology ; Siblings/psychology ; }, abstract = {The article's aim is to evaluate the application of the evolutionary principles of kin selection, reproductive value, and resource holding power to the understanding of family violence. The principles are described in relation to specific predictions and the mechanisms underlying these. Predictions are evaluated for physical violence perpetrated by (a) parents to unrelated children, (b) parents to genetic offspring, and (c) offspring to parents and between (d) siblings and (e) sexual partners. Precise figures for risks have been calculated where possible. The major conclusions are that most of the evidence is consistent with evolutionary predictions derived from kin selection and reproductive value: There were (a) higher rates of violence to stepchildren, (b) a decline in violence with the age of offspring, and (c) an increase in violence with parental age, while (d) violence between siblings was generally at a low level and concerned resource disputes. The issue of distinguishing evolutionary from alternative explanations is addressed throughout and is problematic for predictions derived from reproductive value. The main evolutionary explanation for male partner violence, mate guarding as a result of paternity uncertainty, cannot explain Western studies where sex differences in control and violence between partners were absent, although other aspects of male partner violence are consistent with it, and it may explain sex differences in traditional cultures. Recurrent problems in evaluating the evidence were to control for possible confounds and thus to distinguish evolutionary from alternative explanations. Suggestions are outlined to address this and other issues arising from the review.}, } @article {pmid22774226, year = {2012}, author = {Yeh, AY and Gardner, A}, title = {A general ploidy model for the evolution of helping in viscous populations.}, journal = {Journal of theoretical biology}, volume = {304}, number = {}, pages = {297-303}, doi = {10.1016/j.jtbi.2012.04.004}, pmid = {22774226}, issn = {1095-8541}, mesh = {Animals ; *Biological Evolution ; Competitive Behavior ; Female ; *Helping Behavior ; Male ; *Models, Genetic ; *Ploidies ; Population Dynamics ; Reproduction ; Selection, Genetic/genetics ; Sexual Behavior, Animal ; }, abstract = {There is growing interest in understanding how kin selection drives the evolution of social behaviours in viscous populations. A key result, that has inspired much work on this topic, is the exact cancellation of the genetic relatedness and kin competition effects of dispersal in the simplest models of population viscosity, such that a reduction in the rate of dispersal neither promotes nor inhibits the evolution of helping behaviour. This theoretical result has been demonstrated for populations characterised by haploid, diploid and haplodiploid modes of inheritance. Here we develop a model of general ploidy that recovers these three scenarios as special cases and allows examination of scenarios that have not been considered previously. Specifically, we: clarify the importance of the implicit assumption of monandry in previous models; show that the cancellation result obtains in some models of ploidy but not in others; and reveal that the cancellation result obtains for different reasons in different models of ploidy. The cancellation result therefore hinges upon a population's genetic system as well as its demography.}, } @article {pmid22759286, year = {2012}, author = {Hall, DW and Goodisman, MA}, title = {The effects of kin selection on rates of molecular evolution in social insects.}, journal = {Evolution; international journal of organic evolution}, volume = {66}, number = {7}, pages = {2080-2093}, doi = {10.1111/j.1558-5646.2012.01602.x}, pmid = {22759286}, issn = {1558-5646}, mesh = {Alleles ; Animals ; Ants/genetics ; Bees/genetics ; *Evolution, Molecular ; Female ; Insecta/*genetics ; Male ; Models, Genetic ; *Selection, Genetic ; Social Behavior ; }, abstract = {The evolution of sociality represented a major transition point in biological history. The most advanced societies, such as those displayed by social insects, consist of reproductive and nonreproductive castes. The caste system fundamentally affects the way natural selection operates. Specifically, selection acts directly on reproductive castes, such as queens, but only indirectly through the process of kin selection on nonreproductive castes, such as workers. In this study, we present theoretical analyses to determine the rate of substitution at loci expressed exclusively in the queen or worker castes. We show that the rate of substitution is the same for queen- and worker-selected loci when the queen is singly mated. In contrast, when a queen is multiply mated, queen-selected loci show higher rates of substitution for adaptive alleles and lower rates of substitution for deleterious alleles than worker-selected loci. We compare our theoretical expectations to previously obtained genomic data from the honeybee, Apis mellifera, where queens mate multiply and the fire ant, Solenopsis invicta, where queens mate singly and find that rates of evolution of queen- and worker-selected loci are consistent with our predictions. Overall, our research tests theoretical expectations using empirically obtained genomic data to better understand the evolution of advanced societies.}, } @article {pmid22759285, year = {2012}, author = {Rodrigues, AM and Gardner, A}, title = {Evolution of helping and harming in heterogeneous populations.}, journal = {Evolution; international journal of organic evolution}, volume = {66}, number = {7}, pages = {2065-2079}, doi = {10.1111/j.1558-5646.2012.01594.x}, pmid = {22759285}, issn = {1558-5646}, mesh = {Animals ; *Biological Evolution ; *Environment ; Genetic Variation ; *Helping Behavior ; Models, Genetic ; *Selection, Genetic ; }, abstract = {There has been much interest in understanding how demographic factors can mediate social evolution in viscous populations. Here, we examine the impact of heterogeneity in patch quality--that is, the availability of reproductive resources for each breeder--upon the evolution of helping and harming behaviors. We find that, owing to a cancellation of relatedness and kin competition effects, the evolution of obligate and facultative helping and harming is not influenced by the degree of viscosity in populations characterized by either spatial or temporal heterogeneity in patch quality. However, facultative helping and harming may be favored when there is both spatial and temporal heterogeneity in patch quality, with helping and harming being favored in both high-quality and low-quality patches. We highlight the prospect for using kin selection theory to explain within-population variation in social behavior, and point to the need for further theoretical and empirical investigation of this topic.}, } @article {pmid22694128, year = {2012}, author = {Gardner, A}, title = {Evolution of maternal care in diploid and haplodiploid populations.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {8}, pages = {1479-1486}, doi = {10.1111/j.1420-9101.2012.02551.x}, pmid = {22694128}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; *Diploidy ; Female ; *Haploidy ; *Maternal Behavior ; *Models, Biological ; Social Behavior ; }, abstract = {Maternal care has been suggested to evolve more readily in haplodiploid populations. Because maternal care appears to have been a prerequisite for the evolution of eusociality, this effect potentially explains the apparent preponderance of haplodiploidy among eusocial taxa. Here, I use a kin selection approach to model the evolution of maternal care in diploid and haplodiploid populations. In contrast to previous suggestions, I find that haplodiploidy may inhibit as well as promote the evolution of maternal care. Moreover, I find that the haplodiploidy effect vanishes in outbred populations if gene effects average rather than add together. I confirm these analytical results using numerical simulation of an explicit population genetics model. This analysis casts doubt upon the idea that haplodiploidy has promoted the evolution of maternal care and, consequently, the evolution of eusociality.}, } @article {pmid22648154, year = {2012}, author = {Rumbaugh, KP and Trivedi, U and Watters, C and Burton-Chellew, MN and Diggle, SP and West, SA}, title = {Kin selection, quorum sensing and virulence in pathogenic bacteria.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1742}, pages = {3584-3588}, pmid = {22648154}, issn = {1471-2954}, mesh = {Animals ; Bacterial Proteins/genetics ; Female ; Liver/microbiology ; Mice ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/*pathogenicity/*physiology ; *Quorum Sensing ; *Selection, Genetic ; Skin/microbiology ; Trans-Activators/genetics ; Virulence ; Wounds and Injuries/microbiology/pathology ; }, abstract = {Bacterial growth and virulence often depends upon the cooperative release of extracellular factors excreted in response to quorum sensing (QS). We carried out an in vivo selection experiment in mice to examine how QS evolves in response to variation in relatedness (strain diversity), and the consequences for virulence. We started our experiment with two bacterial strains: a wild-type that both produces and responds to QS signal molecules, and a lasR (signal-blind) mutant that does not release extracellular factors in response to signal. We found that: (i) QS leads to greater growth within hosts; (ii) high relatedness favours the QS wild-type; and (iii) low relatedness favours the lasR mutant. Relatedness matters in our experiment because, at relatively low relatedness, the lasR mutant is able to exploit the extracellular factors produced by the cells that respond to QS, and hence increase in frequency. Furthermore, our results suggest that because a higher relatedness favours cooperative QS, and hence leads to higher growth, this will also lead to a higher virulence, giving a relationship between relatedness and virulence that is in the opposite direction to that usually predicted by virulence theory.}, } @article {pmid22647036, year = {2012}, author = {Arora, N and Van Noordwijk, MA and Ackermann, C and Willems, EP and Nater, A and Greminger, M and Nietlisbach, P and Dunkel, LP and Utami Atmoko, SS and Pamungkas, J and Perwitasari-Farajallah, D and Van Schaik, CP and Krützen, M}, title = {Parentage-based pedigree reconstruction reveals female matrilineal clusters and male-biased dispersal in nongregarious Asian great apes, the Bornean orang-utans (Pongo pygmaeus).}, journal = {Molecular ecology}, volume = {21}, number = {13}, pages = {3352-3362}, doi = {10.1111/j.1365-294X.2012.05608.x}, pmid = {22647036}, issn = {1365-294X}, mesh = {Animals ; DNA, Mitochondrial/genetics ; Female ; *Genetic Variation ; *Genetics, Population ; Haplotypes ; Male ; Molecular Sequence Data ; Pedigree ; Pongo pygmaeus/*genetics ; Sequence Analysis, DNA ; }, abstract = {Philopatry and sex-biased dispersal have a strong influence on population genetic structure, so the study of species dispersal patterns and evolutionary mechanisms shaping them are of great interest. Particularly nongregarious mammalian species present an underexplored field of study: despite their lower levels of sociality compared to group-living species, interactions among individuals do occur, providing opportunities for cryptic kin selection. Among the least gregarious primates are orang-utans (genus: Pongo), in which preferential associations among females have nevertheless been observed, but for which the presence of kin structures was so far unresolved because of the equivocal results of previous genetic studies. To clarify relatedness and dispersal patterns in orang-utans, we examined the largest longitudinal set of individuals with combined genetic, spatial and behavioural data. We found that males had significantly higher mitochondrial DNA (mtDNA) variation and more unique haplotypes, thus underscoring their different maternal ancestries compared to females. Moreover, pedigree reconstruction based on 24 highly polymorphic microsatellite markers and mtDNA haplotypes demonstrated the presence of three matrilineal clusters of generally highly related females with substantially overlapping ranges. In orang-utans and possibly other nongregarious species, comparing average biparental relatedness (r) of males and females to infer sex-biased dispersal is extremely problematic. This is because the opportunistic sampling regime frequently employed in nongregarious species, combined with overlapping space use of distinct matrilineal clusters, leads to a strong downward bias when mtDNA lineage membership is ignored. Thus, in nongregarious species, correct inferences of dispersal can only be achieved by combining several genetic approaches with detailed spatial information.}, } @article {pmid22593110, year = {2012}, author = {Dickins, TE and Rahman, Q}, title = {The extended evolutionary synthesis and the role of soft inheritance in evolution.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1740}, pages = {2913-2921}, pmid = {22593110}, issn = {1471-2954}, mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; *Epigenesis, Genetic ; *Heredity ; Humans ; Mice ; }, abstract = {In recent years, a number of researchers have advocated extending the modern synthesis in evolutionary biology. One of the core arguments made in favour of an extension comes from work on soft inheritance systems, including transgenerational epigenetic effects, cultural transmission and niche construction. In this study, we outline this claim and then take issue with it. We argue that the focus on soft inheritance has led to a conflation of proximate and ultimate causation, which has in turn obscured key questions about biological organization and calibration across the life span to maximize average lifetime inclusive fitness. We illustrate this by presenting hypotheses that we believe incorporate the core phenomena of soft inheritance and will aid in understanding them.}, } @article {pmid22579553, year = {2012}, author = {Ohtsuki, H}, title = {Does synergy rescue the evolution of cooperation? An analysis for homogeneous populations with non-overlapping generations.}, journal = {Journal of theoretical biology}, volume = {307}, number = {}, pages = {20-28}, doi = {10.1016/j.jtbi.2012.04.030}, pmid = {22579553}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Cooperative Behavior ; Genetic Fitness ; *Models, Biological ; Phylogeny ; Population Dynamics ; Selection, Genetic ; }, abstract = {Recent developments of social evolution theory have revealed conditions under which cooperation is favored by natural selection. Effects of population structure on the evolution of cooperation have been one of the central questions in this issue, and inclusive fitness analyses have unveiled two different selective forces that favor cooperation; the direct fitness effect to the helper and the indirect fitness benefit to the helper via its kin. Although these theoretical frameworks have made a significant contribution to our understanding of cooperative traits, there is still one factor to be taken into account, synergy. Synergy means a nonlinear effect that arises when two individuals help each other. In other words, it represents deviation from additivity, to which inclusive fitness theory has paid relatively little attention. Here I provide a theoretical result on the possibility that synergy favors the evolution of cooperation. For homogeneously structured populations with non-overlapping generations, I show that incorporating synergistic effects does not rescue the evolution of cooperation. Potential factors that could enable synergy to rescue the evolution of cooperation are also discussed.}, } @article {pmid22568752, year = {2012}, author = {Jaatinen, K and Noreikiene, K and Merilä, J and Ost, M}, title = {Kin association during brood care in a facultatively social bird: active discrimination or by-product of partner choice and demography?.}, journal = {Molecular ecology}, volume = {21}, number = {13}, pages = {3341-3351}, doi = {10.1111/j.1365-294X.2012.05603.x}, pmid = {22568752}, issn = {1365-294X}, mesh = {Animals ; Anseriformes/*genetics/physiology ; Female ; *Genetics, Population ; Genotype ; Microsatellite Repeats ; *Nesting Behavior ; Population Density ; Sequence Analysis, DNA ; *Social Behavior ; }, abstract = {Intra-group relatedness does not necessarily imply kin selection, a leading explanation for social evolution. An overlooked mechanism for generating population genetic structure is variation in longevity and fecundity, referred to as individual quality, affecting kin structure and the potential for cooperation. Individual quality also affects choosiness in partner choice, a key process explaining cooperation through direct fitness benefits. Reproductive skew theory predicts that relatedness decreases with increasing group size, but this relationship could also arise because of quality-dependent demography and partner choice, without active kin association. We addressed whether brood-rearing eider (Somateria mollissima) females preferentially associated with kin using a 6-year data set with individuals genotyped at 19 microsatellite loci and tested whether relatedness decreased with increasing female group size. We also determined the relationship between local relatedness and indices of female age and body condition. We further examined whether the level of female intracoalition relatedness differed from background relatedness in any year. As predicted, median female intra-group relatedness decreased with increasing female group size. However, the proportion of related individuals increased with advancing female age, and older females prefer smaller brood-rearing coalitions, potentially producing a negative relationship between group size and relatedness. There were considerable annual fluctuations in the level of relatedness between coalition-forming females, and in 1year this level exceeded that expected by random association. Thus, both passive and active mechanisms govern kin associations in brood-rearing eiders. Eiders apparently can discriminate between kin, but the benefits of doing so may vary over time.}, } @article {pmid22544168, year = {2012}, author = {Nesse, RM and Ganten, D and Gregory, TR and Omenn, GS}, title = {Evolutionary molecular medicine.}, journal = {Journal of molecular medicine (Berlin, Germany)}, volume = {90}, number = {5}, pages = {509-522}, pmid = {22544168}, issn = {1432-1440}, support = {U54ES017885/ES/NIEHS NIH HHS/United States ; U54DA021519/DA/NIDA NIH HHS/United States ; P30 ES017885/ES/NIEHS NIH HHS/United States ; U54 DA021519/DA/NIDA NIH HHS/United States ; UL1 RR024986/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Disease/genetics ; *Evolution, Molecular ; Genetic Pleiotropy ; Humans ; *Medicine ; Polymorphism, Genetic ; Selection, Genetic ; }, abstract = {Evolution has long provided a foundation for population genetics, but some major advances in evolutionary biology from the twentieth century that provide foundations for evolutionary medicine are only now being applied in molecular medicine. They include the need for both proximate and evolutionary explanations, kin selection, evolutionary models for cooperation, competition between alleles, co-evolution, and new strategies for tracing phylogenies and identifying signals of selection. Recent advances in genomics are transforming evolutionary biology in ways that create even more opportunities for progress at its interfaces with genetics, medicine, and public health. This article reviews 15 evolutionary principles and their applications in molecular medicine in hopes that readers will use them and related principles to speed the development of evolutionary molecular medicine.}, } @article {pmid22498803, year = {2012}, author = {Seki, M}, title = {Intra-individual conflicts between autosomal and X-linked altruistic genes: evolutionary perspectives of sex-specific grandmothering.}, journal = {Journal of theoretical biology}, volume = {304}, number = {}, pages = {273-285}, doi = {10.1016/j.jtbi.2012.03.032}, pmid = {22498803}, issn = {1095-8541}, mesh = {*Altruism ; *Biological Evolution ; Female ; Game Theory ; *Genes, X-Linked ; Humans ; *Intergenerational Relations ; Male ; *Models, Genetic ; Residence Characteristics ; Selection, Genetic/genetics ; Sex Factors ; }, abstract = {Alloparental care by females toward their grandoffspring can evolve by kin selection. Previous theoretical studies predicted that selection favors autosomal and X-chromosomal genes, causing altruism toward maternal grandoffspring and paternal granddaughters, respectively, and two corresponding types of biased grandparental investment are suggested by empirical studies on human populations. Using discrete-time two-locus-two-allele models, I examined a possible conflict between the autosomal and the X-chromosomal altruistic genes over the carrier female's time and resources. This conflict is expected to occur when each grandmother has access to only maternal or paternal grandchildren as a result of her residence situation. The conditions under which each or both kinds of altruistic genes evolve (against non-altruistic genes) mainly represent the conflicting relationship between the autosomal and X-chromosomal altruistic genes. In addition, depending on the settings, the models exhibit bistable or periodic behaviors, and one type of gene can be considered parasitic in the latter behavior. On the whole, the results suggest that the X-chromosomal altruistic genes rather than the autosomal ones exhibit more difficulty increasing or fixing with this kind of conflict.}, } @article {pmid22496080, year = {2012}, author = {Briga, M and Pen, I and Wright, J}, title = {Care for kin: within-group relatedness and allomaternal care are positively correlated and conserved throughout the mammalian phylogeny.}, journal = {Biology letters}, volume = {8}, number = {4}, pages = {533-536}, pmid = {22496080}, issn = {1744-957X}, mesh = {Animals ; Bayes Theorem ; *Behavior, Animal ; Cooperative Behavior ; Female ; Mammals/classification/genetics/*psychology ; Maternal Behavior/*psychology ; Microsatellite Repeats ; *Phylogeny ; Population Density ; Reproduction ; Social Behavior ; Social Environment ; Species Specificity ; }, abstract = {With an increasing amount of data becoming available, comparative analyses have called attention to the associations between cooperative breeding, monogamy and relatedness. We focus here upon the association between allomaternal care and relatedness among females within a social unit. Previous studies found a positive association, but such results date back to before molecular tools were in common use, they considered only a few mammalian orders, neglected phylogenetic clustering and/or did not correct for group sizes. Here, we use molecular data on relatedness from 44 species of mammals to investigate the phylogenetic clustering of, and the association between, allomaternal care and relatedness among females within a social unit. We find (i) a strong phylogenetic signal for allomaternal care and a moderate one for relatedness and group size, and (ii) a positive association between relatedness and allomaternal care, even when correcting for the smaller than average group sizes in species with allomaternal care. We also find that, in species without allomaternal care, adult females often live with unrelated females even when groups are small. We discuss these results in the light of recent evidence for the role of kin selection and the monogamy hypothesis in cooperative breeding.}, } @article {pmid22487312, year = {2012}, author = {Frank, SA}, title = {Natural selection. IV. The Price equation.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {6}, pages = {1002-1019}, pmid = {22487312}, issn = {1420-9101}, support = {U01 GM076499/GM/NIGMS NIH HHS/United States ; U01 GM076499-05/GM/NIGMS NIH HHS/United States ; U01 GM 76499/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Ecosystem ; Gene Frequency ; Genetics, Population ; Inheritance Patterns ; *Models, Statistical ; Phenotype ; Population Dynamics ; *Selection, Genetic ; }, abstract = {The Price equation partitions total evolutionary change into two components. The first component provides an abstract expression of natural selection. The second component subsumes all other evolutionary processes, including changes during transmission. The natural selection component is often used in applications. Those applications attract widespread interest for their simplicity of expression and ease of interpretation. Those same applications attract widespread criticism by dropping the second component of evolutionary change and by leaving unspecified the detailed assumptions needed for a complete study of dynamics. Controversies over approximation and dynamics have nothing to do with the Price equation itself, which is simply a mathematical equivalence relation for total evolutionary change expressed in an alternative form. Disagreements about approach have to do with the tension between the relative valuation of abstract versus concrete analyses. The Price equation's greatest value has been on the abstract side, particularly the invariance relations that illuminate the understanding of natural selection. Those abstract insights lay the foundation for applications in terms of kin selection, information theory interpretations of natural selection and partitions of causes by path analysis. I discuss recent critiques of the Price equation by Nowak and van Veelen.}, } @article {pmid22483741, year = {2012}, author = {Drewell, RA and Lo, N and Oxley, PR and Oldroyd, BP}, title = {Kin conflict in insect societies: a new epigenetic perspective.}, journal = {Trends in ecology & evolution}, volume = {27}, number = {7}, pages = {367-373}, doi = {10.1016/j.tree.2012.02.005}, pmid = {22483741}, issn = {1872-8383}, mesh = {Animals ; *DNA Methylation ; Female ; *Genomic Imprinting ; *Insecta ; Male ; Mammals/genetics/growth & development ; *Social Behavior ; }, abstract = {The social hymenopterans (ants, wasps and bees) have all the enzymatic and genetic mechanisms necessary for the functional modification of DNA by methylation. Methylation appears to play a central role in shaping the developmental processes that give rise to the different castes. However, could DNA methylation have other roles in social insects? Theoretical arguments predict that male and female hymenopterans can be in conflict over the reproductive potential of their female offspring. An exciting prospect for future research is to examine the possibility that queens and males imprint the genomes of their gametes using DNA methylation to manipulate the reproductive potential of their progeny in ways that favour the inclusive fitness of the parent.}, } @article {pmid22464193, year = {2012}, author = {Woyciechowski, M and Kuszewska, K}, title = {Swarming generates rebel workers in honeybees.}, journal = {Current biology : CB}, volume = {22}, number = {8}, pages = {707-711}, doi = {10.1016/j.cub.2012.02.063}, pmid = {22464193}, issn = {1879-0445}, mesh = {Animals ; Bees/*physiology ; Body Weight ; Female ; Hypopharynx/physiology ; Male ; Ovary/physiology ; *Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {According to kin selection theory, the colony kin structure of eusocial insects motivates workers' altruistic behaviors and therefore their sterility or restricted reproduction [1]. Indeed, theory and cross-species comparison confirm that workers engage in their own reproduction depending on relatedness among colony members [2, 3]. We show that in a honeybee colony, the workers switch from their typical altruistic role to a more selfish one if at their larval stage there are environmental cues of an upcoming decline in intracolony relatedness. This happens inevitably when a colony multiplies by swarming and replaces the mother queen with her daughter, because the mother queen's workers are faced with rearing the sister queen's offspring related to them half as much as between sisters. Workers developing from the mother queen's eggs immediately after swarming, in a temporarily queenless colony, had more ovarioles in their ovaries and less-developed hypopharyngeal glands producing brood food than control workers reared in queenright conditions. These "rebel" workers were more engaged in laying their own male-determined eggs than in rearing offspring, whether or not the sister queen was present in the colony. The finding of this previously unknown rebel strategy confirms that kin selection shapes both cooperation and conflict in honeybee societies.}, } @article {pmid22437614, year = {2012}, author = {Penney, HD and Hassall, C and Skevington, JH and Abbott, KR and Sherratt, TN}, title = {A comparative analysis of the evolution of imperfect mimicry.}, journal = {Nature}, volume = {483}, number = {7390}, pages = {461-464}, pmid = {22437614}, issn = {1476-4687}, mesh = {Animals ; *Biological Evolution ; Bites and Stings ; Body Size/physiology ; Diptera/*anatomy & histology/classification/*physiology ; Models, Biological ; Molecular Mimicry/*physiology ; Phylogeny ; Predatory Behavior/physiology ; Selection, Genetic ; }, abstract = {Although exceptional examples of adaptation are frequently celebrated, some outcomes of natural selection seem far from perfect. For example, many hoverflies (Diptera: Syrphidae) are harmless (Batesian) mimics of stinging Hymenoptera. However, although some hoverfly species are considered excellent mimics, other species bear only a superficial resemblance to their models and it is unclear why this is so. To evaluate hypotheses that have been put forward to explain interspecific variation in the mimetic fidelity of Palearctic Syrphidae we use a comparative approach. We show that the most plausible explanation is that predators impose less selection for mimetic fidelity on smaller hoverfly species because they are less profitable prey items. In particular, our findings, in combination with previous results, allow us to reject several key hypotheses for imperfect mimicry: first, human ratings of mimetic fidelity are positively correlated with both morphometric measures and avian rankings, indicating that variation in mimetic fidelity is not simply an illusion based on human perception; second, no species of syrphid maps out in multidimensional space as being intermediate in appearance between several different hymenopteran model species, as the multimodel hypothesis requires; and third, we find no evidence for a negative relationship between mimetic fidelity and abundance, which calls into question the kin-selection hypothesis. By contrast, a strong positive relationship between mimetic fidelity and body size supports the relaxed-selection hypothesis, suggesting that reduced predation pressure on less profitable prey species limits the selection for mimetic perfection.}, } @article {pmid22437174, year = {2012}, author = {Van Dyken, JD and Wade, MJ}, title = {Detecting the molecular signature of social conflict: theory and a test with bacterial quorum sensing genes.}, journal = {The American naturalist}, volume = {179}, number = {4}, pages = {436-450}, pmid = {22437174}, issn = {1537-5323}, support = {R01 GM084238/GM/NIGMS NIH HHS/United States ; GM00279912-02/GM/NIGMS NIH HHS/United States ; }, mesh = {*Evolution, Molecular ; Genes, Bacterial/genetics ; *Models, Genetic ; Polymorphism, Genetic ; Quorum Sensing/*genetics ; }, abstract = {Extending social evolution theory to the molecular level opens the door to an unparalleled abundance of data and statistical tools for testing alternative hypotheses about the long-term evolutionary dynamics of cooperation and conflict. To this end, we take a collection of known sociality genes (bacterial quorum sensing [QS] genes), model their evolution in terms of patterns that are detectable using gene sequence data, and then test model predictions using available genetic data sets. Specifically, we test two alternative hypotheses of social conflict: (1) the "adaptive" hypothesis that cheaters are maintained in natural populations by frequency-dependent balancing selection as an evolutionarily stable strategy and (2) the "evolutionary null" hypothesis that cheaters are opposed by purifying kin selection yet exist transiently because of their recurrent introduction into populations by mutation (i.e., kin selection-mutation balance). We find that QS genes have elevated within- and among-species sequence variation, nonsignificant signatures of natural selection, and putatively small effect sizes of mutant alleles, all patterns predicted by our evolutionary null model but not by the stable cheater hypothesis. These empirical findings support our theoretical prediction that QS genes experience relaxed selection due to nonclonality of social groups, conditional expression, and the individual-level advantage enjoyed by cheaters. Furthermore, cheaters are evolutionarily transient, persisting in populations because of their recurrent introduction by mutation and not because they enjoy a frequency-dependent fitness advantage.}, } @article {pmid22388945, year = {2011}, author = {Koster, J}, title = {Interhousehold meat sharing among Mayangna and Miskito horticulturalists in Nicaragua.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {22}, number = {4}, pages = {394-415}, pmid = {22388945}, issn = {1936-4776}, mesh = {Cooperative Behavior ; Cultural Characteristics ; Family Relations ; Feeding Behavior/*ethnology ; Humans ; *Meat ; Nicaragua/ethnology ; Nutrition Surveys ; Social Networking ; *Social Support ; }, abstract = {Recent analyses of food sharing in small-scale societies indicate that reciprocal altruism maintains interhousehold food transfers, even among close kin. In this study, matrix-based regression methods are used to test the explanatory power of reciprocal altruism, kin selection, and tolerated scrounging. In a network of 35 households in Nicaragua's Bosawas Reserve, the significant predictors of food sharing include kinship, interhousehold distance, and reciprocity. In particular, resources tend to flow from households with relatively more meat to closely related households with little, as predicted by kin selection. This generalization is especially true of household dyads with mother-offspring relationships, which suggests that studies of food sharing may benefit from distinctions between lineal and collateral kin. Overall, this analysis suggests that exchanges among kin are primarily associated with differences in need, not reciprocity. Finally, although large game is distributed widely, qualitative observations indicate that hunters typically do not relinquish control of the distribution in ways predicted by costly signaling theory.}, } @article {pmid22388804, year = {2011}, author = {Wood, BM and Marlowe, FW}, title = {Dynamics of postmarital residence among the Hadza: a kin investment model.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {22}, number = {1-2}, pages = {128-138}, pmid = {22388804}, issn = {1936-4776}, mesh = {Africa, Northern ; Cooperative Behavior ; Culture ; Family Characteristics/*ethnology ; Family Relations/*ethnology ; Female ; Food ; Humans ; Male ; Marriage/*ethnology ; Parity ; Population Dynamics ; Residence Characteristics/*statistics & numerical data ; Sex Factors ; }, abstract = {When we have asked Hadza whether married couples should live with the family of the wife (uxorilocally) or the family of the husband (virilocally), we are often told that young couples should spend the first years of a marriage living with the wife's family, and then later, after a few children have been born, the couple has more freedom--they can continue to reside with the wife's kin, or else they could join the husband's kin, or perhaps live in a camp where there are no close kin. In this paper, we address why shifts in kin coresidence patterns may arise in the later years of a marriage, after the birth of children. To do so, we model the inclusive fitness costs that wives might experience from leaving their own kin and joining their husband's kin as a function of the number of children in their nuclear family. Our model suggests that such shifts should become less costly to wives as their families grow. This simple model may help explain some of the dynamics of postmarital residence among the Hadza and offer insight into the dynamics of multilocal residence, the most prevalent form of postmarital residence among foragers.}, } @article {pmid22388802, year = {2011}, author = {Alvard, M}, title = {Genetic and cultural kinship among the Lamaleran whale hunters.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {22}, number = {1-2}, pages = {89-107}, pmid = {22388802}, issn = {1936-4776}, mesh = {Animals ; *Anthropology, Cultural ; Child ; Communication ; Family Characteristics/*ethnology ; Family Relations/*ethnology ; Female ; Food ; *Genetics, Population ; Humans ; Indonesia ; Male ; *Social Support ; Whales ; }, abstract = {The human ability to form large, coordinated groups is among our most impressive social adaptations. Larger groups facilitate synergistic economies of scale for cooperative breeding, such economic tasks as group hunting, and success in conflict with other groups. In many organisms, genetic relationships provide the structure for sociality to evolve via the process of kin selection, and this is the case, to a certain extent, for humans. But assortment by genetic affiliation is not the only mechanism that can bring people together. Affinity based on symbolically mediated and socially constructed identity, or cultural kinship, structures much of human ultrasociality. This paper examines how genetic kinship and two kinds of cultural kinship--affinal kinship and descent--structure the network of cooperating whale hunters in the village of Lamalera, Indonesia. Social network analyses show that each mechanism of assortment produces characteristic networks of different sizes, each more or less conducive to the task of hunting whales. Assortment via close genetic kin relationships (r = 0.5) produces a smaller, denser network. Assortment via less-close kin relations (r = 0.125) produces a larger but less dense network. Affinal networks are small and diffuse; lineage networks are larger, discrete, and very dense. The roles that genetic and cultural kinship play for structuring human sociality is discussed in the context of these results.}, } @article {pmid22384051, year = {2012}, author = {Baker, CC and Dall, SR and Rankin, DJ}, title = {Kin selection and the evolution of social information use in animal conflict.}, journal = {PloS one}, volume = {7}, number = {2}, pages = {e31664}, pmid = {22384051}, issn = {1932-6203}, mesh = {Animals ; *Behavior, Animal ; Conflict, Psychological ; Cooperative Behavior ; Decision Making ; Game Theory ; Models, Statistical ; Models, Theoretical ; Mutation ; Phenotype ; Probability ; Selection, Genetic ; *Sexual Behavior, Animal ; Social Behavior ; }, abstract = {Animals often use social information about conspecifics in making decisions about cooperation and conflict. While the importance of kin selection in the evolution of intraspecific cooperation and conflict is widely acknowledged, few studies have examined how relatedness influences the evolution of social information use. Here we specifically examine how relatedness affects the evolution of a stylised form of social information use known as eavesdropping. Eavesdropping involves individuals escalating conflicts with rivals observed to have lost their last encounter and avoiding fights with those seen to have won. We use a game theoretical model to examine how relatedness affects the evolution of eavesdropping, both when strategies are discrete and when they are continuous or mixed. We show that relatedness influences the evolution of eavesdropping, such that information use peaks at intermediate relatedness. Our study highlights the importance of considering kin selection when exploring the evolution of complex forms of information use.}, } @article {pmid22380565, year = {2012}, author = {Bernhardt, B and Lampert, KP and Leese, F and Mayer, C and Tollrian, R}, title = {Are shoals of minnow Phoxinus phoxinus formed by close kin?.}, journal = {Journal of fish biology}, volume = {80}, number = {3}, pages = {713-721}, doi = {10.1111/j.1095-8649.2011.03198.x}, pmid = {22380565}, issn = {1095-8649}, mesh = {Animal Communication ; Animals ; *Behavior, Animal ; Cyprinidae/genetics/*physiology ; Genotype ; Microsatellite Repeats ; *Social Behavior ; }, abstract = {A molecular analysis examining the level of relatedness in shoaling minnows Phoxinus phoxinus was conducted. The results revealed that individuals from within the same shoal were not more closely related to each other than to individuals from other shoals. This led to the conclusion that Schreckstoff may be less likely to have evolved in the context of kin selection.}, } @article {pmid22372617, year = {2012}, author = {Lehmann, L}, title = {The stationary distribution of a continuously varying strategy in a class-structured population under mutation-selection-drift balance.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {4}, pages = {770-787}, doi = {10.1111/j.1420-9101.2012.02472.x}, pmid = {22372617}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; Game Theory ; *Genetic Drift ; Genetics, Population ; *Models, Genetic ; Mutation ; *Selection, Genetic ; }, abstract = {Many traits and/or strategies expressed by organisms are quantitative phenotypes. Because populations are of finite size and genomes are subject to mutations, these continuously varying phenotypes are under the joint pressure of mutation, natural selection and random genetic drift. This article derives the stationary distribution for such a phenotype under a mutation-selection-drift balance in a class-structured population allowing for demographically varying class sizes and/or changing environmental conditions. The salient feature of the stationary distribution is that it can be entirely characterized in terms of the average size of the gene pool and Hamilton's inclusive fitness effect. The exploration of the phenotypic space varies exponentially with the cumulative inclusive fitness effect over state space, which determines an adaptive landscape. The peaks of the landscapes are those phenotypes that are candidate evolutionary stable strategies and can be determined by standard phenotypic selection gradient methods (e.g. evolutionary game theory, kin selection theory, adaptive dynamics). The curvature of the stationary distribution provides a measure of the stability by convergence of candidate evolutionary stable strategies, and it is evaluated explicitly for two biological scenarios: first, a coordination game, which illustrates that, for a multipeaked adaptive landscape, stochastically stable strategies can be singled out by letting the size of the gene pool grow large; second, a sex-allocation game for diploids and haplo-diploids, which suggests that the equilibrium sex ratio follows a Beta distribution with parameters depending on the features of the genetic system.}, } @article {pmid22357709, year = {2012}, author = {Fraley, RC and Tancredy, CM}, title = {Twin and sibling attachment in a nationally representative sample.}, journal = {Personality & social psychology bulletin}, volume = {38}, number = {3}, pages = {308-316}, doi = {10.1177/0146167211432936}, pmid = {22357709}, issn = {1552-7433}, mesh = {Adolescent ; Adult ; Aged ; Aged, 80 and over ; Cross-Sectional Studies ; Female ; Humans ; Male ; Middle Aged ; *Object Attachment ; *Sibling Relations ; Siblings/*psychology ; Twins, Dizygotic/*psychology ; Twins, Monozygotic/*psychology ; }, abstract = {The objective of this research was to evaluate the hypothesis that twin relationships are attachments, using data from a nationally representative sample. The results indicated that twin siblings were more likely than nontwin siblings to be attached to their siblings. Moreover, analyses indicated that both attachment theoretical and inclusive fitness perspectives are necessary for explaining these findings. Namely, twins were more likely to be attached than nontwin siblings, as expected from an attachment perspective. But identical twins were more likely than fraternal twins to be attached to one another, as might be expected from an inclusive fitness perspective. Cross-sectional analyses indicated that older people are less likely than younger people to use their sibling as an attachment figure compared to younger people and that married adults are less likely to use their sibling as an attachment figure than nonmarried people.}, } @article {pmid22321157, year = {2012}, author = {Robinson, SP and Kennington, WJ and Simmons, LW}, title = {Assortative mating for relatedness in a large naturally occurring population of Drosophila melanogaster.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {4}, pages = {716-725}, doi = {10.1111/j.1420-9101.2012.02466.x}, pmid = {22321157}, issn = {1420-9101}, mesh = {Animals ; Drosophila melanogaster/anatomy & histology/*genetics/physiology ; Female ; *Inbreeding ; Male ; Mating Preference, Animal ; Multivariate Analysis ; Sex Characteristics ; Sexual Behavior, Animal ; }, abstract = {New theoretical work on kin selection and inclusive fitness benefits predicts that individuals will sometimes choose close or intermediate relatives as mates to maximize their fitness. However, empirical examples supporting such predictions are rare. In this study, we look for such evidence in a natural population of Drosophila melanogaster. We compared mating and nonmating individuals to test whether mating was nonrandom with respect to relatedness. Consistent with optimal inbreeding, males were more closely related to their mate than to randomly sampled females. However, all individuals collected mating showed higher relatedness and males were not significantly more related to their mate than to other mating females. We also found a negative relationship between relatedness and fecundity. Our results are consistent with the hypothesis that inclusive fitness benefits may drive inbreeding tolerance despite direct costs to fitness; however, an experimental approach is needed to investigate the link between mate preference and relatedness.}, } @article {pmid22320709, year = {2012}, author = {Concannon, MR and Stein, AC and Uy, JA}, title = {Kin selection may contribute to lek evolution and trait introgression across an avian hybrid zone.}, journal = {Molecular ecology}, volume = {21}, number = {6}, pages = {1477-1486}, doi = {10.1111/j.1365-294X.2012.05474.x}, pmid = {22320709}, issn = {1365-294X}, support = {//Medical Research Council/United Kingdom ; }, mesh = {Animals ; *Biological Evolution ; Color ; Feathers/*physiology ; Female ; Male ; Mating Preference, Animal ; Passeriformes/*genetics/physiology ; *Selection, Genetic ; *Sexual Behavior, Animal ; Visual Perception ; }, abstract = {Understanding the mechanism(s) that favour cooperation among individuals competing for the same resources provides direct insights into the evolution of grouping behaviour. In a hybrid zone between golden-/yellow-collared (Manacus vitellinus) and white-collared (Manacus candei) manakins, males form aggregations composed of white and yellow males solely to attract females ('mixed leks'). Previous work shows that yellow males in these mixed leks experience a clear mating advantage over white males, resulting in the preferential introgression of yellow plumage allele(s) into the white species. However, the yellow male mating advantage only occurs in mixed leks with high frequencies of yellow males, and only a few of these males probably mate. Hence, it remains unclear why unsuccessful males join leks. Here, we used microsatellite markers to estimate pairwise relatedness among males within and between leks to test whether indirect genetic benefits of helping kin ('kin selection') can promote grouping. We found that yellow males are significantly more related to each other within than between leks, while relatedness among white males did not differ within and between leks. This suggests that yellow males may indirectly enhance their own reproductive success by preferentially lekking with relatives because yellow plumage is under positive frequency-dependent selection (positive FDS). Our results are consistent with the hypothesis that kin selection may promote grouping and facilitate positive FDS for yellow males, mediating the movement of yellow plumage across this hybrid zone.}, } @article {pmid22219391, year = {2012}, author = {Krause, ET and Krüger, O and Kohlmeier, P and Caspers, BA}, title = {Olfactory kin recognition in a songbird.}, journal = {Biology letters}, volume = {8}, number = {3}, pages = {327-329}, pmid = {22219391}, issn = {1744-957X}, mesh = {Animals ; Behavior, Animal ; *Cues ; Finches/genetics/growth & development/*physiology ; *Smell ; Social Behavior ; }, abstract = {The ability to recognize close relatives in order to cooperate or to avoid inbreeding is widespread across all taxa. One accepted mechanism for kin recognition in birds is associative learning of visual or acoustic cues. However, how could individuals ever learn to recognize unfamiliar kin? Here, we provide the first evidence for a novel mechanism of kin recognition in birds. Zebra finch (Taeniopygia guttata) fledglings are able to distinguish between kin and non-kin based on olfactory cues alone. Since olfactory cues are likely to be genetically based, this finding establishes a neglected mechanism of kin recognition in birds, particularly in songbirds, with potentially far-reaching consequences for both kin selection and inbreeding avoidance.}, } @article {pmid25892846, year = {2012}, author = {Loretto, MC and Fraser, ON and Bugnyar, T}, title = {Ontogeny of Social Relations and Coalition Formation in Common Ravens (Corvus corax).}, journal = {International journal of comparative psychology}, volume = {25}, number = {3}, pages = {180-194}, pmid = {25892846}, issn = {0889-3667}, support = {Y 366/FWF_/Austrian Science Fund FWF/Austria ; }, abstract = {The social intelligence hypothesis, originally developed for primates to explain their high intelligence and large relative brain size, assumes that challenges posed by social life in complex societies with many group members lead to the evolution of advanced cognitive abilities. In birds, pair-bonded species have larger brains than non-pair bonded species, indicating that the quality of social relationships better predicts social complexity than group size. Ravens are a long-term monogamous and territorial species, renowned for their sophisticated socio-cognitive skills and complex social relationships. Notably, during their early years they live in fission-fusion-like non-breeder societies in which social relationships could be of particular importance. Here we observed the development of dominance and affiliative relationships in 12 hand-raised captive ravens, examining the influence of age, sex and kinship on social interactions. Furthermore, we investigated at which developmental step a stable hierarchy emerged, whether third-party interventions played a role and how selectively birds intervened in others' conflicts. At 4-5 months post-fledging, we found an increase in socio-positive behaviour and a decrease in aggression, along with the establishment of a linear dominance rank hierarchy. In line with kin selection theory, siblings exhibited a greater degree of tolerance and engaged in more socio-positive behaviour. In their first few months, ravens frequently intervened in others' conflicts but supported mainly the aggressor; later on, their support became more selective towards kin and close social partners. These findings indicate that ravens engage in sophisticated social behaviours and form stable relationships already in their first year of life.}, } @article {pmid22195019, year = {2011}, author = {Chiang, YS and Takahashi, N}, title = {Network homophily and the evolution of the pay-it-forward reciprocity.}, journal = {PloS one}, volume = {6}, number = {12}, pages = {e29188}, pmid = {22195019}, issn = {1932-6203}, mesh = {Adaptation, Psychological ; *Biological Evolution ; *Cooperative Behavior ; Game Theory ; Humans ; Models, Biological ; *Social Support ; }, abstract = {The pay-it-forward reciprocity is a type of cooperative behavior that people who have benefited from others return favors to third parties other than the benefactors, thus pushing forward a cascade of kindness. The phenomenon of the pay-it-forward reciprocity is ubiquitous, yet how it evolves to be part of human sociality has not been fully understood. We develop an evolutionary dynamics model to investigate how network homophily influences the evolution of the pay-it-forward reciprocity. Manipulating the extent to which actors carrying the same behavioral trait are linked in networks, the computer simulation model shows that strong network homophily helps consolidate the adaptive advantage of cooperation, yet introducing some heterophily to the formation of network helps advance cooperation's scale further. Our model enriches the literature of inclusive fitness theory by demonstrating the conditions under which cooperation or reciprocity can be selected for in evolution when social interaction is not confined exclusively to relatives.}, } @article {pmid22150796, year = {2012}, author = {Frank, SA}, title = {Natural selection. III. Selection versus transmission and the levels of selection.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {2}, pages = {227-243}, pmid = {22150796}, issn = {1420-9101}, support = {U01 GM076499/GM/NIGMS NIH HHS/United States ; U01 GM076499-05/GM/NIGMS NIH HHS/United States ; U01-GM-76499/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; Genetic Variation ; Models, Biological ; Population Dynamics ; *Selection, Genetic ; Stochastic Processes ; Time Factors ; }, abstract = {George Williams defined an evolutionary unit as hereditary information for which the selection bias between competing units dominates the informational decay caused by imperfect transmission. In this article, I extend Williams' approach to show that the ratio of selection bias to transmission bias provides a unifying framework for diverse biological problems. Specific examples include Haldane and Lande's mutation-selection balance, Eigen's error threshold and quasispecies, Van Valen's clade selection, Price's multilevel formulation of group selection, Szathmáry and Demeter's evolutionary origin of primitive cells, Levin and Bull's short-sighted evolution of HIV virulence, Frank's timescale analysis of microbial metabolism and Maynard Smith and Szathmáry's major transitions in evolution. The insights from these diverse applications lead to a deeper understanding of kin selection, group selection, multilevel evolutionary analysis and the philosophical problems of evolutionary units and individuality.}, } @article {pmid22144168, year = {2012}, author = {Friesen, ML and Jones, EI}, title = {Modelling the evolution of mutualistic symbioses.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {804}, number = {}, pages = {481-499}, doi = {10.1007/978-1-61779-361-5_24}, pmid = {22144168}, issn = {1940-6029}, mesh = {Adaptation, Biological ; Bacteria/*genetics ; *Biological Evolution ; Game Theory ; Genetics, Population ; Mathematical Concepts ; *Models, Biological ; Software ; Symbiosis/*genetics ; }, abstract = {Mutualistic microbial symbioses are one of the key innovations in the evolution of biological diversity, enabling the expansion of species' niches and the production of sophisticated structures such as the eukaryotic cell. For some of the best-studied cases, we are beginning to have network models of symbiotic metabolism, but this work is in its infancy and has not been developed with an evolutionary perspective. However, theoreticians have long been interested in how these symbioses arise and persist and have applied modelling approaches from economics, evolution, ecology, and sociobology to a number of fundamental questions. We provide an overview of these questions, followed by specific modelling examples. We cover economic game theory, including the Prisoner's Dilemma, the Snowdrift game, and biological markets. We also describe the eco-evolutionary framework of adaptive dynamics, inclusive fitness, and population genetic models. We aim to provide insight into the strengths and weaknesses of each approach and into how current evolutionary methods can benefit an understanding of the mechanistic basis of host-symbiont interactions elucidated by molecular network models.}, } @article {pmid22122288, year = {2012}, author = {Bos, N and Lefèvre, T and Jensen, AB and d'Ettorre, P}, title = {Sick ants become unsociable.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {2}, pages = {342-351}, doi = {10.1111/j.1420-9101.2011.02425.x}, pmid = {22122288}, issn = {1420-9101}, mesh = {Aggression ; Animals ; Ants/*microbiology/physiology ; *Behavior, Animal ; Metarhizium/*physiology ; *Social Behavior ; }, abstract = {Parasites represent a severe threat to social insects, which form high-density colonies of related individuals, and selection should favour host traits that reduce infection risk. Here, using a carpenter ant (Camponotus aethiops) and a generalist insect pathogenic fungus (Metarhizium brunneum), we show that infected ants radically change their behaviour over time to reduce the risk of colony infection. Infected individuals (i) performed less social interactions than their uninfected counterparts, (ii) did not interact with brood anymore and (iii) spent most of their time outside the nest from day 3 post-infection until death. Furthermore, infected ants displayed an increased aggressiveness towards non-nestmates. Finally, infected ants did not alter their cuticular chemical profile, suggesting that infected individuals do not signal their physiological status to nestmates. Our results provide evidence for the evolution of unsociability following pathogen infection in a social animal and suggest an important role of inclusive fitness in driving such evolution.}, } @article {pmid22111867, year = {2012}, author = {Hunt, JH}, title = {A conceptual model for the origin of worker behaviour and adaptation of eusociality.}, journal = {Journal of evolutionary biology}, volume = {25}, number = {1}, pages = {1-19}, doi = {10.1111/j.1420-9101.2011.02421.x}, pmid = {22111867}, issn = {1420-9101}, mesh = {Adaptation, Biological ; Altruism ; Animals ; *Behavior, Animal ; *Biological Evolution ; *Genetic Fitness ; *Models, Biological ; Phenotype ; Phylogeny ; *Selection, Genetic ; *Social Behavior ; *Wasps/genetics ; }, abstract = {In a model based on the wasp family Vespidae, the origin of worker behaviour, which constitutes the eusociality threshold, is not based on relatedness, therefore the origin of eusociality does not depend on inclusive fitness, and workers at the eusociality threshold are not altruistic. Instead, incipient workers and queens behave selfishly and are subject to direct natural selection. Beyond the eusociality threshold, relatedness enables 'soft inheritance' as the framework for initial adaptations of eusociality. At the threshold of irreversibility, queen and worker castes become fixed in advanced eusociality. Transitions from solitary to facultative, facultative to primitive, and primitive to advanced eusociality occur via exaptation, phenotypic accommodation and genetic assimilation. Multilevel selection characterizes the solitary to highly eusocial transition, but components of multilevel selection vary across levels of eusociality. Roles of behavioural flexibility and developmental plasticity in the evolutionary process equal or exceed those of genotype.}, } @article {pmid22108863, year = {2011}, author = {van Zweden, JS and Vitikainen, E and d'Ettorre, P and Sundström, L}, title = {Do cuticular hydrocarbons provide sufficient information for optimal sex allocation in the ant Formica exsecta?.}, journal = {Journal of chemical ecology}, volume = {37}, number = {12}, pages = {1365-1373}, pmid = {22108863}, issn = {1573-1561}, mesh = {Animals ; Ants/chemistry/genetics/*physiology ; Cues ; Demography ; Female ; Finland ; Hydrocarbons/*chemistry ; Male ; Reproduction ; Sex Ratio ; }, abstract = {Split sex ratio theory predicts that when kin structure varies among colonies of social insects, in order to maximize the inclusive fitness, colonies with relatively high sister-sister relatedness should specialize in producing reproductive females, whereas in those with relatively low sister-sister relatedness workers should bias their sex ratio towards males. However, in order to achieve this, workers need to be able to reliably assess the type of colony in which they live. The information on colony kin structure may be encoded in cuticular hydrocarbons (CHCs), assuming that genetic variability translates accurately into chemical variability. However, in genetically heterogeneous colonies, too accurate information may encourage the pursuit of individual interests through nepotistic behavior and reduce colony efficiency or cause social disruption. In this study, we estimated how well variability of CHC recognition cues reflects colony kin structure in the ant Formica exsecta. Our results show that CHC variability does not covary with kin structure or the overall genetic diversity of the colony, and that patrilines and matrilines can have distinct CHC profiles in some but not all colonies. However, within-colony relatedness remains the key determinant of colony sex ratios. Based on our results, CHC variability cannot serve as accurate information on within-colony relatedness, kin structure, or full-sib affiliation, nor do workers seem to use colony CHC variability as a proxy for sex-ratio adjustment. The use of this type of information thus could lead workers to make mistakes, and it remains unclear how colonies of Formica exsecta adjust offspring sex ratio to their optimal value.}, } @article {pmid22072602, year = {2012}, author = {File, AL and Murphy, GP and Dudley, SA}, title = {Fitness consequences of plants growing with siblings: reconciling kin selection, niche partitioning and competitive ability.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1727}, pages = {209-218}, pmid = {22072602}, issn = {1471-2954}, mesh = {Genotype ; Phenotype ; *Plant Development ; *Plant Physiological Phenomena ; Plants/genetics ; Population Density ; Population Dynamics ; }, abstract = {Plant studies that have investigated the fitness consequences of growing with siblings have found conflicting evidence that can support different theoretical frameworks. Depending on whether siblings or strangers have higher fitness in competition, kin selection, niche partitioning and competitive ability have been invoked. Here, we bring together these processes in a conceptual synthesis and argue that they can be co-occurring. We propose that these processes can be reconciled and argue for a trait-based approach of measuring natural selection instead of the fitness-based approach to the study of sibling competition. This review will improve the understanding of how plants interact socially under competitive situations, and provide a framework for future studies.}, } @article {pmid22008256, year = {2011}, author = {Brouwer, L and Van De Pol, M and Atema, E and Cockburn, A}, title = {Strategic promiscuity helps avoid inbreeding at multiple levels in a cooperative breeder where both sexes are philopatric.}, journal = {Molecular ecology}, volume = {20}, number = {22}, pages = {4796-4807}, doi = {10.1111/j.1365-294X.2011.05325.x}, pmid = {22008256}, issn = {1365-294X}, mesh = {Animals ; Female ; Genotyping Techniques ; *Inbreeding ; Male ; Microsatellite Repeats ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; Songbirds/genetics/*physiology ; }, abstract = {In cooperative breeders, the tension between the opposing forces of kin selection and kin competition is at its most severe. Although philopatry facilitates kin selection, it also increases the risk of inbreeding. When dispersal is limited, extra-pair paternity might be an important mechanism to avoid inbreeding, but evidence for this is equivocal. The red-winged fairy-wren is part of a genus of cooperative breeders with extreme levels of promiscuity and male philopatry, but is unique in that females are also strongly philopatric. Here, we test the hypothesis that promiscuity is an important inbreeding avoidance mechanism when both sexes are philopatric. Levels of extra-pair paternity were substantial (70% of broods), but did not arise through females mating with their helpers, but via extra-group mating. Offspring were more likely to be sired by extra-pair males when the social pair was closely related, and these extra-pair males were genetically less similar to the female than the social male and thus, inbreeding is avoided through extra-pair mating. Females were consistent in their choice of the extra-pair sire over time and preferred early moulting males. Despite neighbouring males often being close kin, they sired 37% of extra-pair offspring. However, females that gained paternity from neighbours were typically less related to them than females that gained paternity further away. Our study is the first to suggest that mating with both closely related social partners and neighbours is avoided. Such sophistication in inbreeding avoidance strategies is remarkable, as the extreme levels of promiscuity imply that social context may provide little cue to relatedness.}, } @article {pmid21993501, year = {2012}, author = {Leggett, HC and El Mouden, C and Wild, G and West, S}, title = {Promiscuity and the evolution of cooperative breeding.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1732}, pages = {1405-1411}, pmid = {21993501}, issn = {1471-2954}, mesh = {Animals ; *Biological Evolution ; Breeding ; Cooperative Behavior ; Female ; Genetic Fitness ; Male ; Models, Biological ; *Sexual Behavior, Animal ; Social Behavior ; }, abstract = {Empirical data suggest that low levels of promiscuity have played a key role in the evolution of cooperative breeding and eusociality. However, from a theoretical perspective, low levels of promiscuity can favour dispersal away from the natal patch, and have been argued to select against cooperation in a way that cannot be explained by inclusive fitness theory. Here, we use an inclusive fitness approach to model selection to stay and help in a simple patch-structured population, with strict density dependence, where helping increases the survival of the breeder on the patch. Our model predicts that the level of promiscuity has either no influence or a slightly positive influence on selection for helping. This prediction is driven by the fact that, in our model, staying to help leads to increased competition between relatives for the breeding position-when promiscuity is low (and relatedness is high), the best way to aid relatives is by dispersing to avoid competing with them. Furthermore, we found the same results with an individual-based simulation, showing that this is not an area where inclusive fitness theory 'gets it wrong'. We suggest that our predicted influence of promiscuity is sensitive to biological assumptions, and that if a possibly more biologically relevant scenario were examined, where helping provided fecundity benefits and there was not strict density dependence, then low levels of promiscuity would favour helping, as has been observed empirically.}, } @article {pmid21982746, year = {2011}, author = {Wild, G and Pizzari, T and West, SA}, title = {Sexual conflict in viscous populations: the effect of the timing of dispersal.}, journal = {Theoretical population biology}, volume = {80}, number = {4}, pages = {298-316}, doi = {10.1016/j.tpb.2011.09.002}, pmid = {21982746}, issn = {1096-0325}, mesh = {Animals ; *Competitive Behavior/physiology ; Female ; Male ; Population Dynamics ; *Selection, Genetic ; Sex Factors ; *Sexual Behavior, Animal ; Time Factors ; }, abstract = {In recent years, there has been increasing theoretical and empirical examination of how sexual conflict can arise between males and females. However, much this work has implicitly assumed that interactions take place in panmictic populations with complete dispersal, where interactions are between unrelated individuals. Here, we examine the consequences of limited dispersal and population structure for the evolution of a male phenotype that is associated with the males pre- and post-copulatory reproductive success, using an inclusive-fitness based analysis applied to group-structured populations. We show that: (i) the sex-specific timing of the dispersal phase of the life cycle can drive the evolution of sexual conflict; (ii) the inclusive fitness of a female in this conflict is determined solely by direct (i.e. personal) effects on its own competitive ability. Our analysis is supported by results from individual-based simulations of multi-level selection. Our results support the suggestion that kin selection can influence the evolution of sexual conflict, but reveal that such a role might be more complex than previously appreciated when sex-specific life histories are taken into consideration. We discuss the implications of our results for sexual conflict in various species of insects, but focus primarily on dipteran flies of the family Sepsidae.}, } @article {pmid21967441, year = {2011}, author = {Tully, T and Lambert, A}, title = {The evolution of postreproductive life span as an insurance against indeterminacy.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {10}, pages = {3013-3020}, doi = {10.1111/j.1558-5646.2011.01347.x}, pmid = {21967441}, issn = {1558-5646}, mesh = {Animals ; Arthropods/genetics/*physiology ; *Biological Evolution ; Female ; Longevity ; Male ; *Models, Genetic ; Reproduction ; Selection, Genetic ; }, abstract = {Postreproductive life span remains a puzzle for evolutionary biologists. The explanation of increased inclusive fitness through parental care after reproduction that applies for humans is unrealistic for many species. We propose a new selective mechanism, independent of parental care, which relies on the hypothesis that postreproductive life span can evolve as an insurance against indeterminacy: longer life expectancy reduces the risk of dying by chance before the cessation of reproductive activity. We demonstrate numerically that the duration of evolved postreproductive life span is indeed expected to increase with variability in life span duration. An unprecedented assay of 11 strains of the collembola Folsomia candida shows the existence of (1) postreproductive life span in the absence of parental care; (2) genetic variability in mean postreproductive life span and postreproductive life span variability itself; (3) strong genetic correlation between latter traits. This new explanation brings along the novel idea that loose canalization of a trait (here, somatic life span) can itself act as a selective pressure on other traits.}, } @article {pmid21967419, year = {2011}, author = {Fogarty, L and Strimling, P and Laland, KN}, title = {The evolution of teaching.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {10}, pages = {2760-2770}, doi = {10.1111/j.1558-5646.2011.01370.x}, pmid = {21967419}, issn = {1558-5646}, support = {232823/ERC_/European Research Council/International ; BB/D015812/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; *Biological Evolution ; Genetics, Population ; Humans ; Models, Biological ; Social Behavior ; *Teaching ; }, abstract = {Teaching, alongside imitation, is widely thought to underlie the success of humanity by allowing high-fidelity transmission of information, skills, and technology between individuals, facilitating both cumulative knowledge gain and normative culture. Yet, it remains a mystery why teaching should be widespread in human societies but extremely rare in other animals. We explore the evolution of teaching using simple genetic models in which a single tutor transmits adaptive information to a related pupil at a cost. Teaching is expected to evolve where its costs are outweighed by the inclusive fitness benefits that result from the tutor's relatives being more likely to acquire the valuable information. We find that teaching is not favored where the pupil can easily acquire the information on its own, or through copying others, or for difficult to learn traits, where teachers typically do not possess the information to pass on to relatives. This leads to a narrow range of traits for which teaching would be efficacious, which helps to explain the rarity of teaching in nature, its unusual distribution, and its highly specific nature. Further models that allow for cumulative cultural knowledge gain suggest that teaching evolved in humans because cumulative culture renders otherwise difficult-to-acquire valuable information available to teach.}, } @article {pmid21967416, year = {2011}, author = {Biernaskie, JM and West, SA and Gardner, A}, title = {Are greenbeards intragenomic outlaws?.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {10}, pages = {2729-2742}, doi = {10.1111/j.1558-5646.2011.01355.x}, pmid = {21967416}, issn = {1558-5646}, mesh = {Alleles ; Conflict, Psychological ; Genetics, Population ; Hierarchy, Social ; *Models, Genetic ; Phenotype ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Greenbeard genes identify copies of themselves in other individuals and cause their bearer to behave nepotistically toward those individuals. Hence, they can be favored by kin selection, irrespective of the degree of genealogical relationship between social partners. Although greenbeards were initially developed as a thought experiment, a number of recent discoveries of greenbeard alleles in real populations have led to a resurgence of interest in their evolutionary dynamics and consequences. One issue over which there has been disagreement is whether greenbeards lead to intragenomic conflict. Here, to clarify the "outlaw" status of greenbeards, we develop population genetic models that formally examine selection of greenbeard phenotypes under the control of different loci. We find that, in many cases, greenbeards are not outlaws because selection for or against the greenbeard phenotype is the same across all loci. In contrast, when social interactions are between genealogical kin, we find that greenbeards can be outlaws because different genes can be selected in different directions. Hence, the outlaw status of greenbeard genes crucially depends upon the particular biological details. We also clarify whether greenbeards are favored due to direct or indirect fitness effects and address the relationship of the greenbeard effect to sexual antagonism and reciprocity.}, } @article {pmid21966265, year = {2011}, author = {Torney, CJ and Berdahl, A and Couzin, ID}, title = {Signalling and the evolution of cooperative foraging in dynamic environments.}, journal = {PLoS computational biology}, volume = {7}, number = {9}, pages = {e1002194}, pmid = {21966265}, issn = {1553-7358}, mesh = {*Animal Communication ; Animals ; *Appetitive Behavior ; Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; *Feeding Behavior ; *Models, Biological ; Swallows ; }, abstract = {Understanding cooperation in animal social groups remains a significant challenge for evolutionary theory. Observed behaviours that benefit others but incur some cost appear incompatible with classical notions of natural selection; however, these behaviours may be explained by concepts such as inclusive fitness, reciprocity, intra-specific mutualism or manipulation. In this work, we examine a seemingly altruistic behaviour, the active recruitment of conspecifics to a food resource through signalling. Here collective, cooperative behaviour may provide highly nonlinear benefits to individuals, since group functionality has the potential to be far greater than the sum of the component parts, for example by enabling the effective tracking of a dynamic resource. We show that due to this effect, signalling to others is an evolutionarily stable strategy under certain environmental conditions, even when there is a cost associated to this behaviour. While exploitation is possible, in the limiting case of a sparse, ephemeral but locally abundant nutrient source, a given environmental profile will support a fixed number of signalling individuals. Through a quantitative analysis, this effective carrying capacity for cooperation is related to the characteristic length and time scales of the resource field.}, } @article {pmid22947949, year = {2011}, author = {Danielsbacka, M and Tanskanen, AO and Jokela, M and Rotkirch, A}, title = {Grandparental child care in Europe: evidence for preferential investment in more certain kin.}, journal = {Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior}, volume = {9}, number = {1}, pages = {3-24}, pmid = {22947949}, issn = {1474-7049}, support = {OGHA 04-064//PHS HHS/United States ; P01 AG005842/AG/NIA NIH HHS/United States ; P01 AG08291/AG/NIA NIH HHS/United States ; P30 AG12815/AG/NIA NIH HHS/United States ; R21 AG025169/AG/NIA NIH HHS/United States ; U01 AG09740-13S2/AG/NIA NIH HHS/United States ; Y1-AG-4553-01/AG/NIA NIH HHS/United States ; }, mesh = {Child ; Child Care/*psychology ; Europe/ethnology ; Female ; Humans ; Intergenerational Relations/*ethnology ; Male ; Middle Aged ; Nuclear Family/ethnology ; Paternity ; Sex Factors ; }, abstract = {Theories of kin selection and parental investment predict stronger investment in children and grandchildren by women and maternal kin. Due to paternity uncertainty, parental and grandparental investments along paternal lineages are based on less certain genetic relatedness with the children and grandchildren. Additionally, the hypothesis of preferential investment (Laham, Gonsalkorale, and von Hippel, 2005) predicts investment to vary according to available investment options. Two previous studies have tested this hypothesis with small samples and conflicting results. Using the second wave of the large and multinational Survey of Health, Ageing and Retirement in Europe (SHARE), collected in 2006-07, we study the preferential investment hypothesis in contemporary Europe based on self-reported grandparental provision of child care. We predict that 1) maternal grandmothers provide most care for their grandchildren, followed by maternal grandfathers, paternal grandmothers and last by paternal grandfathers; 2) maternal grandfathers and paternal grandmothers provide equal amounts of care when the latter do not have grandchildren via a daughter; 3) women who have grandchildren via both a daughter and a son will look after the children of the daughter more; and 4) men who have grandchildren via both a daughter and a son will look after the children of the daughter more. Results support all four hypotheses and provide evidence for the continuing effects of paternity uncertainty in contemporary kin behavior.}, } @article {pmid25567938, year = {2010}, author = {Wade, MJ and Bijma, P and Ellen, ED and Muir, W}, title = {Group selection and social evolution in domesticated animals.}, journal = {Evolutionary applications}, volume = {3}, number = {5-6}, pages = {453-465}, pmid = {25567938}, issn = {1752-4571}, support = {R01 GM065414/GM/NIGMS NIH HHS/United States ; }, abstract = {Social interactions, especially those involving competition among individuals, are important in domesticated livestock and in natural populations. The heritability of traits affected by such interactions has two components, one originating in the individual like that of classical traits (direct effects) and the other originating in other group members (indirect effects). The latter type of trait represents a significant source of 'hidden heritability' and it requires population structure and knowledge from relatives in order to access it for selective breeding. When ignored, competitive interactions may increase as an indirect response to direct selection, resulting in diminished yields. We illustrate how population genetic structure affects the response to selection of traits with indirect genetic effects using population genetic and quantitative genetic theory. Population genetic theory permits us to connect our results to the existing body of theory on kin and group selection in natural populations. The quantitative genetic perspective allows us to see how breeders have used knowledge from relatives and family selection in the domestication of plants and animals to improve the welfare and production of livestock by incorporating social genetic effects in the breeding program. We illustrate the central features of these models by reviewing empirical studies from domesticated chickens.}, } @article {pmid25567918, year = {2010}, author = {Dyer, AR and Brown, CS and Espeland, EK and McKay, JK and Meimberg, H and Rice, KJ}, title = {The role of adaptive trans-generational plasticity in biological invasions of plants.}, journal = {Evolutionary applications}, volume = {3}, number = {2}, pages = {179-192}, pmid = {25567918}, issn = {1752-4571}, abstract = {High-impact biological invasions often involve establishment and spread in disturbed, high-resource patches followed by establishment and spread in biotically or abiotically stressful areas. Evolutionary change may be required for the second phase of invasion (establishment and spread in stressful areas) to occur. When species have low genetic diversity and short selection history, within-generation phenotypic plasticity is often cited as the mechanism through which spread across multiple habitat types can occur. We show that trans-generational plasticity (TGP) can result in pre-adapted progeny that exhibit traits associated with increased fitness both in high-resource patches and in stressful conditions. In the invasive sedge, Cyperus esculentus, maternal plants growing in nutrient-poor patches can place disproportional number of propagules into nutrient-rich patches. Using the invasive annual grass, Aegilops triuncialis, we show that maternal response to soil conditions can confer greater stress tolerance in seedlings in the form of greater photosynthetic efficiency. We also show TGP for a phenological shift in a low resource environment that results in greater stress tolerance in progeny. These lines of evidence suggest that the maternal environment can have profound effects on offspring success and that TGP may play a significant role in some plant invasions.}, } @article {pmid26181750, year = {2008}, author = {Stewart-Williams, S}, title = {Human Beings as Evolved Nepotists : Exceptions to the Rule and Effects of Cost of Help.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {19}, number = {4}, pages = {414-425}, pmid = {26181750}, issn = {1045-6767}, abstract = {Inclusive fitness theory provides a compelling explanation for the evolution of altruism among kin. However, a completely satisfactory account of non-kin altruism is still lacking. The present study compared the level of altruism found among siblings with that found among friends and mates and sought to reconcile the findings with an evolutionary explanation for human altruism. Participants (163 males and 156 females) completed a questionnaire about help given to a sibling, friend, or mate. Overall, participants gave friends and mates as much or more help than they gave siblings. However, as the cost of help increased, siblings received a progressively larger share of the help, whereas friends and mates received a progressively smaller share, despite the fact that participants were closer emotionally to friends and mates than they were to siblings. These findings help to explain the relative standing of friends and mates as recipients of altruistic aid.}, } @article {pmid26181616, year = {2008}, author = {Crittenden, AN and Marlowe, FW}, title = {Allomaternal Care among the Hadza of Tanzania.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {19}, number = {3}, pages = {249-262}, pmid = {26181616}, issn = {1045-6767}, abstract = {Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase a mother's fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest percentage of time holding children. The higher the degree of relatedness among kin, the more time they spend holding, supporting the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion.}, } @article {pmid26181464, year = {2008}, author = {Webster, GD and Bryan, A and Crawford, CB and McCarthy, L and Cohen, BH}, title = {Lineage, Sex, and Wealth as Moderators of Kin Investment : Evidence from Inheritances.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {19}, number = {2}, pages = {189-210}, pmid = {26181464}, issn = {1045-6767}, abstract = {Supporting Hamilton's inclusive fitness theory, archival analyses of inheritance patterns in wills have revealed that people invest more of their estates in kin of closer genetic relatedness. Recent classroom experiments have shown that this genetic relatedness effect is stronger for relatives of direct lineage (children, grandchildren) than for relatives of collateral lineage (siblings, nieces, nephews). In the present research, multilevel modeling of more than 1,000 British Columbian wills revealed a positive effect of genetic relatedness on proportions of estates allocated to relatives. This effect was qualified by an interaction with lineage, such that it was stronger for direct than for collateral relatives. Exploratory analyses of the moderating role of benefactors' sex and estate values showed the genetic relatedness effect was stronger among female and wealthier benefactors. The importance of these moderators to understanding kin investment in modern humans is discussed.}, } @article {pmid26181741, year = {2007}, author = {Hames, R and McCabe, C}, title = {Meal sharing among the Ye'kwana.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {18}, number = {1}, pages = {1-21}, pmid = {26181741}, issn = {1045-6767}, abstract = {In this study meal sharing is used as a way of quantifying food transfers between households. Traditional food-sharing studies measure the flow of resources between households. Meal sharing, in contrast, measures food consumption acts according to whether one is a host or a guest in the household as well as the movement of people between households in the context of food consumption. Our goal is to test a number of evolutionary models of food transfers, but first we argue that before one tests models of who should receive food one must understand the adaptiveness of food transfers. For the Ye'kwana, economies of scale in food processing and preparation appear to set the stage for the utility of meal sharing. Evolutionary models of meal sharing, such as kin selection and reciprocal altruism, are evaluated along with non-evolutionary models, such as egalitarian exchange and residential propinquity. In addition, a modified measure of exchange balance-proportional balance-is developed. Reciprocal altruism is shown to be the strongest predictor of exchange intensity and balance.}, } @article {pmid26181609, year = {2006}, author = {Deady, DK and Law Smith, MJ and Kent, JP and Dunbar, RI}, title = {Is priesthood an adaptive strategy? : Evidence from a historical Irish population.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {17}, number = {4}, pages = {393-404}, pmid = {26181609}, issn = {1045-6767}, abstract = {This study examines the socioeconomic and familial background of Irish Catholic priests born between 1867 and 1911. Previous research has hypothesized that lack of marriage opportunities may influence adoption of celibacy as part of a religious institution. The present study traced data from Irish seminary registries for 46 Catholic priests born in County Limerick, Ireland, using 1901 Irish Census returns and Land Valuation records. Priests were more likely to originate from landholding backgrounds, and with landholdings greater in size and wealth than the local average. Priests were found to originate from families with more sons than the national average, but with similar numbers of daughters. These findings are discussed in relation to competition for resources and lineage survival strategies.}, } @article {pmid34517681, year = {2005}, author = {Dierkes, P and Heg, D and Taborsky, M and Skubic, E and Achmann, R}, title = {Genetic relatedness in groups is sex-specific and declines with age of helpers in a cooperatively breeding cichlid.}, journal = {Ecology letters}, volume = {8}, number = {9}, pages = {968-975}, doi = {10.1111/j.1461-0248.2005.00801.x}, pmid = {34517681}, issn = {1461-0248}, abstract = {Kin selection can explain the evolution of cooperative breeding and the distribution of relatives within a population may influence the benefits of cooperative behaviour. We provide genetic data on relatedness in the cooperatively breeding cichlid Neolamprologus pulcher. Helper to breeder relatedness decreased steeply with increasing helper age, particularly to the breeding males. Helper to helper relatedness was age-assortative and also declined with age. These patterns of relatedness could be attributed to territory take-overs by outsiders when breeders had disappeared (more in breeding males), between-group dispersal of helpers and reproductive parasitism. In six of 31 groups females inherited the breeding position of their mother or sister. These matrilines were more likely to occur in large groups. We conclude that the relative fitness benefits of helping gained through kin selection vs. those gained through direct selection depend on helper age and sex.}, } @article {pmid26189622, year = {2005}, author = {Ziker, J and Schnegg, M}, title = {Food sharing at meals : Kinship, reciprocity, and clustering in the taimyr autonomous okrug, northern Russia.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {16}, number = {2}, pages = {178-210}, pmid = {26189622}, issn = {1045-6767}, abstract = {The presence of a kinship link between nuclear families is the strongest predictor of interhousehold sharing in an indigenous, predominantly Dolgan food-sharing network in northern Russia. Attributes such as the summed number of hunters in paired households also account for much of the variation in sharing between nuclear families. Differences in the number of hunters in partner households, as well as proximity and producer/consumer ratios of households, were investigated with regard to cost-benefit models. The subset of households involved in reciprocal meal sharing is 26 of 84 household host-guest pairs. The frequency of reciprocal meal sharing between families in this subset is positively correlated with average household relatedness. The evolution of cooperation through clustering may illuminate the relationship between kinship and reciprocity at this most intimate level of food sharing.}, } @article {pmid26189515, year = {2005}, author = {Quinlan, RJ and Flinn, MV}, title = {Kinship, sex, and fitness in a Caribbean community.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {16}, number = {1}, pages = {32-57}, pmid = {26189515}, issn = {1045-6767}, abstract = {Patterns of human kinship commonly involve preferential treatment of relatives based on lineal descent (lineages) rather than degree of genetic relatedness (kindreds), presenting a challenge for inclusive fitness theory. Here, we examine effects of lineage and kindred characteristics on reproductive success (RS) and number of grandchildren for 130 men and 124 women in a horticultural community on Dominica. Kindreds had little effect on fitness independently of lineage characteristics. Fitness increased with the number of lineal relatives residing in the community but decreased beyond an apparently optimal lineage size, suggesting resource enhancement and competition among kin. Female-biased patrilineage sex ratio was positively associated with men's fitness, while male-biased matrilineage sex ratio was positively associated with women's fitness. Number of brothers in the community was negatively associated with men's, but not women's, fitness. Parents and number of sisters had no effect on either male or female reproduction; however, women with younger sisters had higher RS, suggesting benefits of kin support for childcare. In sum, imposed norms for lineage social organization may enhance lineal ancestors' inclusive fitness at a cost to individual inclusive fitness.}, } @article {pmid26189514, year = {2005}, author = {Anderson, KG}, title = {Relatedness and investment in children in South Africa.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {16}, number = {1}, pages = {1-31}, pmid = {26189514}, issn = {1045-6767}, abstract = {Investment in children is examined using a nationally representative sample of 11,211 black (African) households in South Africa. I randomly selected one child from each household in the sample and calculated the average genetic relatedness of the other household members to the focal child. Using multivariate statistical analysis to control for background variables such as age and sex of child, household size, and socioeconomic status, I examine whether the coefficient of relatedness predicts greater household expenditures on food, on health care, and on children's clothing. I also test whether relatedness is associated with health and schooling outcomes. The results are consistent with an inclusive fitness model: Households invest more in children who are more closely related. Two exceptions were found: in rural areas, genetic relatedness was negatively associated with money spent on food and on health care. Explanations for these results are discussed.}, } @article {pmid29641925, year = {2004}, author = {Wenseleers, T and Hart, AG and Ratnieks, FLW}, title = {When Resistance Is Useless: Policing and the Evolution of Reproductive Acquiescence in Insect Societies.}, journal = {The American naturalist}, volume = {164}, number = {6}, pages = {E154-E167}, doi = {10.1086/425223}, pmid = {29641925}, issn = {1537-5323}, abstract = {In social groups composed of kin, inclusive fitness benefits can favor greater cooperation. Alternatively, cooperation can be enforced through the policing of less cooperative individuals. Here, we show that the effect of policing can be twofold: not only can it directly suppress individual selfishness, it can also entirely remove the incentive for individuals to act selfishly in the first place. We term such individual restraint in response to socially imposed policing "acquiescence" and illustrate the concept using examples drawn from the social Hymenoptera (the ants, bees, and wasps). Inclusive fitness models confirm that when a policing system is in place, individuals should be less tempted to act selfishly. This is shown to have important consequences for the resolution of conflict within their societies. For example, it can explain why in many species very few workers attempt to reproduce and why immature females usually do not attempt to develop as queens rather than workers. Although our analyses are primarily focused on the social insects, our conclusions are likely to be general and to apply to other societies as well.}, } @article {pmid29641920, year = {2004}, author = {Gardner, A and West, SA}, title = {Cooperation and Punishment, Especially in Humans.}, journal = {The American naturalist}, volume = {164}, number = {6}, pages = {753-764}, doi = {10.1086/425623}, pmid = {29641920}, issn = {1537-5323}, abstract = {Explaining altruistic cooperation is one of the greatest challenges faced by sociologists, economists, and evolutionary biologists. The problem is determining why an individual would carry out a costly behavior that benefits another. Possible solutions to this problem include kinship, repeated interactions, and policing. Another solution that has recently received much attention is the threat of punishment. However, punishing behavior is often costly for the punisher, and so it is not immediately clear how costly punishment could evolve. We use a direct (neighbor-modulated) fitness approach to analyze when punishment is favored. This methodology reveals that, contrary to previous suggestions, relatedness between interacting individuals is not crucial to explaining cooperation through punishment. In fact, increasing relatedness directly disfavors punishing behavior. Instead, the crucial factor is a positive correlation between the punishment strategy of an individual and the cooperation it receives. This could arise in several ways, such as when facultative adjustment of behavior leads individuals to cooperate more when interacting with individuals who are more likely to punish. More generally, our results provide a clear example of how the fundamental factor driving the evolution of social traits is a correlation between social partners and how this can arise for reasons other than genealogical kinship.}, } @article {pmid24937580, year = {2004}, author = {Driver, K and Abed, RT}, title = {Does having offspring reduce the risk of suicide in women?.}, journal = {International journal of psychiatry in clinical practice}, volume = {8}, number = {1}, pages = {25-29}, doi = {10.1080/13651500310004506}, pmid = {24937580}, issn = {1365-1501}, abstract = {OBJECTIVES: To assess the effect of having offspring, dependant offspring (<18 years), non-dependant offspring (> 18 years) and no offspring on suicide rates in women. Also to ascertain whether the offspring living at home or away from home altered the outcome.

METHODS: Sixty records held by the coroner of female suicides in Rotherham over a 10-year period (1991-2001) were studied. The 1991 Census for South Yorkshire and the Office For National Statistics (England and Wales) provided comparative data for the general population. Data obtained for both groups included the age of the woman, number of children, age of children, whether the children lived with their mother or away from home. The results were subjected to chi-squared statistical analysis.

RESULTS: There was no difference in the percentage of childless women when comparing the female suicide population of Rotherham with the general female population. However, females with offspring living at home regardless of age were significantly underrepresented in our sample (P < 0.001).

CONCLUSION: The protective effect offspring confer on their mother against suicide appears to operate so long as the offspring lives at home irrespective of off spring's age. The protective effect appears to be lost once they leave home. These findings are discussed in the context of the kin selection hypothesis and deCatanzaro's Darwinian hypothesis on human suicide. (Int J Psych Clin Pract 2004; 8: 25-29).}, } @article {pmid30893959, year = {2003}, author = {Ridley, J and Komdeur, J and Sutherland, WJ}, title = {Population regulation in group-living birds: predictive models of the Seychelles warbler.}, journal = {The Journal of animal ecology}, volume = {72}, number = {4}, pages = {588-598}, doi = {10.1046/j.1365-2656.2003.00728.x}, pmid = {30893959}, issn = {1365-2656}, abstract = {A major challenge for population ecology is to predict population responses to novel conditions, such as habitat loss. This frequently involves understanding dispersal decisions, in terms of their consequences for fitness. However, this approach requires detailed data, and is thus often inappropriate for urgent problems on poorly known species. This may be resolved by developing a predictive framework based on well-studied species, for applying to those that are less well understood. Population size, group sizes and habitat occupancy of the Seychelles warbler (Acrocephalus sechellensis) can be predicted by determining the evolutionary stable dispersal strategy. For densities near to demographic equilibrium, regulation results from the combined effects of non-breeding and use of sink habitats. In the Seychelles warbler, resident male non-breeders compete for breeding vacancies on neighbouring territories. The resulting kin competition is a key process for predicting the observed balance between regulation by non-breeding and regulation by sink use. Family groups, in which offspring delay dispersal, hoping to fill a vacancy on a local territory, are common among group-living species. This suggests that kin competition may frequently play a central role in the population regulation of socially complex species. Although all the model variants considered are complex, predictions are shown to be insensitive to a range of simplifications, illustrating that, despite significant evolutionary import at the individual level, some behaviour can be unimportant when considering population level questions. Identifying which behavioural strategies have significant demographic consequences is key to the further development of population models based on fitness maximizing behaviour.}, } @article {pmid26192596, year = {2002}, author = {Grinnell, J}, title = {Modes of cooperation during territorial defense by African lions.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {13}, number = {1}, pages = {85-104}, pmid = {26192596}, issn = {1045-6767}, abstract = {Cooperation during territorial defense allows social groups of African lions to defend access to resources necessary for individual reproductive success. Some forms of cooperation will be dependent upon cognition: reciprocity places greater cognitive demands on participants than does kinship or mutualism. Lions have well-developed cognitive abilities that enable individuals to recognize and interact with others in ways that seem to enhance their inclusive fitness. Male lions appear to cooperate unconditionally, consistently responding to roaring intruders regardless of their male companions' kinship or behavior. Female lions, however, do keep track of the past behavior of their female companions, apparently using the reliability of a companion as one means of assessing the risks posed by approaching intruders. Some "laggard" females may exploit the cooperative tendencies of "leaders" during territorial encounters. Although leader females clearly recognize laggards as such, the costs of tolerating laggards may be less than the benefits leaders gain through territorial defense behavior. Thus, although lions clearly have the cognitive ability to base cooperation on reciprocity, territorial defense cooperation appears instead to be based primarily on mutual benefits to participants for both male and female lions.}, } @article {pmid26192593, year = {2002}, author = {Fehr, E and Fischbacher, U and Gächter, S}, title = {Strong reciprocity, human cooperation, and the enforcement of social norms.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {13}, number = {1}, pages = {1-25}, pmid = {26192593}, issn = {1045-6767}, abstract = {This paper provides strong evidence challenging the self-interest assumption that dominates the behavioral sciences and much evolutionary thinking. The evidence indicates that many people have a tendency to voluntarily cooperate, if treated fairly, and to punish noncooperators. We call this behavioral propensity "strong reciprocity" and show empirically that it can lead to almost universal cooperation in circumstances in which purely self-interested behavior would cause a complete breakdown of cooperation. In addition, we show that people are willing to punish those who behaved unfairly towards a third person or who defected in a Prisoner's Dilemma game with a third person. This suggests that strong reciprocity is a powerful device for the enforcement of social norms involving, for example, food sharing or collective action. Strong reciprocity cannot be rationalized as an adaptive trait by the leading evolutionary theories of human cooperation (in other words, kin selection, reciprocal altruism, indirect reciprocity, and costly signaling theory). However, multilevel selection theories of cultural evolution are consistent with strong reciprocity.}, } @article {pmid26192165, year = {2001}, author = {Bossong, B}, title = {Gender and age differences in inheritance patterns : Why men leave more to their spouses and women more to their children: An experimental analysis.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {12}, number = {2}, pages = {107-122}, pmid = {26192165}, issn = {1045-6767}, abstract = {By analyzing legacies in California from 1890 to 1984 Judge and Hrdy (1992) detected a gender-related difference: Men with children were statistically more likely to leave all of their property to a wife than were mothers to a husband. The authors argue that men were more likely than women to remarry and have additional children. Thus, in order to transfer their wealth to their mutual children, men can leave it to their wives but women can avoid risks by giving it to the children directly. This hypothesis was tested by two experiments in which subjects were asked to put themselves in the position of a person writing a will and allocate the wealth to the surviving spouse and the children. Age and sex of the heir/heiress were experimentally varied. The results support the inclusive fitness interpretation.}, } @article {pmid29592542, year = {2000}, author = {Denison, RF}, title = {Legume Sanctions and the Evolution of Symbiotic Cooperation by Rhizobia.}, journal = {The American naturalist}, volume = {156}, number = {6}, pages = {567-576}, doi = {10.1086/316994}, pmid = {29592542}, issn = {1537-5323}, abstract = {The legume-rhizobium symbiosis is an ideal model for studying the factors that limit the evolution of microbial mutualists into parasites. Legumes are unable to consistently recognize parasitic rhizobia that, once established inside plant cells, use plant resources for their own reproduction rather than for N2 fixation. Evolution of parasitism in rhizobia, driven partly by competition among multiple rhizobial strains infecting the same plant, may be countered by postinfection legume sanctions. Both the biochemical options for rhizobial cheating and the evolutionary effect of legume sanctions depend on differences in rhizobial life history associated with nodule type. In legumes with determinate nodule growth, rhizobia typically retain the ability to reproduce after differentiating into N2-fixing bacteroids. Sanctions against individual bacteroids (e.g., acid hydrolases) would therefore select for cooperative rhizobia. In nodules with indeterminate growth, bacteroids generally lose the ability to reproduce, so legume sanctions against bacteroids would have no effect on rhizobial evolution. Whole-nodule sanctions (e.g., decreased nodule O2 permeability) could be effective, via kin selection of undifferentiated rhizobia that persist in indeterminate nodules and replenish soil populations after nodule senescence. Mixed nodules could reduce the effectiveness of whole-nodule sanctions. The frequency of mixed nodules under field conditions is unknown.}, } @article {pmid30545205, year = {2000}, author = {Gould, L}, title = {Adoption of a Wild orphaned ringtailed lemur infant by natal group members: Adaptive explanations.}, journal = {Primates; journal of primatology}, volume = {41}, number = {4}, pages = {413-419}, pmid = {30545205}, issn = {1610-7365}, abstract = {In December 1992 an infant ringtailed lemur, approximately 7 weeks of age, was orphaned in one of the regularly-censused social groups at the Beza-Mahafaly Reserve, southwestern Madagascar. The infant was initially adopted by a subadult (2 yr-old) male from the group. Continuous-time focal animal data were collected for a 12-hr period, from the time that the infant was retrieved by the young male, in order to document the adoption process. Ten members of the infant's social group (total group number=18) engaged in infant care behaviors over the 12-hr period. The subadult male spent the most time engaged in infant care, and he and one adult female exhibited the highest frequency of caregiving behaviors over the 12-hr period (p<0.001). Four adult males also initially cared for the infant. The orphan was one of only six infants in the reserve population to survive that year. She was censused two years later as an adolescent member of her natal group. Adaptive explanations for this adoption vary depending upon the care-giver. For the subadult male and adult female caregivers, kin selection can be suggested, as the infant was related to all females and immature animals in the group. Adult males may have exhibited caregiving behaviors as a strategy related to affiliation with adult females which could lead to potential mating and reproductive success.}, } @article {pmid26193364, year = {2000}, author = {Draper, P and Hames, R}, title = {Birth order, sibling investment, and fertility among Ju/'Hoansi (!Kung).}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {11}, number = {2}, pages = {117-156}, pmid = {26193364}, issn = {1045-6767}, abstract = {Birth order has been examined over a wide variety of dimensions in the context of modern populations. A consistent message has been that it is better to be born first. The analysis of birth order in this paper is different in several ways from other investigations into birth order effects. First, we examine the effect of birth order in an egalitarian, small-scale, kin-based society, which has not been done before. Second, we use a different outcome measure, fertility, rather than outcome measures of social, psychological, or economic success. We find, third, that being born late in an egalitarian, technologically simple society rather than being born early has a positive outcome on fertility, and fourth, that number of older siblings and sibling set size are even stronger predictors of fertility, especially for males.}, } @article {pmid26196416, year = {1999}, author = {Quinsey, VL and Lalumière, ML and Querée, M and McNaughton, JK}, title = {Perceived crime severity and biological kinship.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {10}, number = {4}, pages = {399-414}, pmid = {26196416}, issn = {1045-6767}, abstract = {Two predictions concerning the perceived severity of crimes can be derived from evolutionary theory. The first, arising from the theory of inclusive fitness, is that crimes in general should be viewed as more serious to the degree that the victim is genetically related to the perpetrator. The second, arising from the deleterious effects of inbreeding depression, is that heterosexual sexual coercion should be perceived as more serious the closer the genetic relationship of victim and perpetrator, particularly when the victim is a female of fertile age. Two hundred and thirty university students estimated the magnitude of the severity of brief crime descriptions in three separate studies. In the first two, the biological kinship of victim and perpetrator was varied, and in the third, the hypothetical genetic relatedness of the subject and the fictitious victim was varied. All three studies found the linear relationships between biological kinship and perceived crime severity predicted by theory.}, } @article {pmid26196335, year = {1999}, author = {Boehm, C}, title = {The natural selection of altruistic traits.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {10}, number = {3}, pages = {205-252}, pmid = {26196335}, issn = {1045-6767}, abstract = {Proponents of the standard evolutionary biology paradigm explain human "altruism" in terms of either nepotism or strict reciprocity. On that basis our underlying nature is reduced to a function of inclusive fitness: human nature has to be totally selfish or nepotistic. Proposed here are three possible paths to giving costly aid to nonrelatives, paths that are controversial because they involve assumed pleiotropic effects or group selection. One path is pleiotropic subsidies that help to extend nepotistic helping behavior from close family to nonrelatives. Another is "warfare"-if and only if warfare recurred in the Paleolithic. The third and most plausible hypothesis is based on the morally based egalitarian syndrome of prehistoric hunter-gatherers, which reduced phenotypic variation at the within-group level, increased it at the between-group level, and drastically curtailed the advantages of free riders. In an analysis consistent with the fundamental tenets of evolutionary biology, these three paths are evaluated as explanations for the evolutionary development of a rather complicated human social nature.}, } @article {pmid26196139, year = {1999}, author = {Hill, E}, title = {Lineage interests and nonreproductive strategies : An evolutionary approach to medieval religious women.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {10}, number = {2}, pages = {109-134}, pmid = {26196139}, issn = {1045-6767}, abstract = {The nonreproductive role of religious women in the European Middle Ages presents the ideal forum for the discussion of elite family strategies within a historical context. I apply the evolutionary concept of kin selection to this group of women in order to explain how a social formation in which religious women failed to reproduce benefited medieval noble lineages. After a brief review of the roles of noble women in the later Middle Ages, I identify two benefits that nonreproductive women provided within a patrilineal inheritance system. First, spatial segregation and Christian ideology together served to curtail the production of offspring who could pose a threat to lineage interests. Second, cloistered noble women served as a strong political and economic bloc that could further lineage interests within a religious context. Finally, I discuss the evolutionary basis for the formation of groups of nonreproductive women. Using the foundation provided by animal behavioral studies, I apply the twin concepts of cooperative breeding and parental manipulation to noble lineages of the medieval period.}, } @article {pmid29585974, year = {1999}, author = {Wolf, JB and Brodie Iii, ED and Moore, AJ}, title = {Interacting Phenotypes and the Evolutionary Process. II. Selection Resulting from Social Interactions.}, journal = {The American naturalist}, volume = {153}, number = {3}, pages = {254-266}, doi = {10.1086/303168}, pmid = {29585974}, issn = {1537-5323}, abstract = {Social interactions often affect the fitness of interactants. Because of this, social selection has been described as a process distinct from other forms of natural selection. Social selection has been predicted to result in different evolutionary dynamics for interacting phenotypes, including rapid or extreme evolution and evolution of altruism. Despite the critical role that social selection plays in theories of social evolution, few studies have measured the force of social selection or the conditions under which this force changes. Here we present a model of social selection acting on interacting phenotypes that can be evaluated independently from the genetics of interacting phenotypes. Our model of social selection is analogous to covariance models of other forms of selection. We observe that an opportunity for social selection exists whenever individual fitness varies as a result of interactions with conspecifics. Social selection occurs, therefore, when variation in fitness due to interactions covaries with traits, resulting in a net force of selection acting on the interacting phenotypes. Thus, there must be a covariance between the phenotypes of the interactants for social selection to exist. This interacting phenotype covariance is important because it measures the degree to which a particular trait covaries with the selective environment provided by conspecifics. A variety of factors, including nonrandom interactions, behavioral modification during interactions, relatedness, and indirect genetic effects may contribute to the covariance of interacting phenotypes, which promotes social selection. The independent force of social selection (measured as a social selection gradient) can be partitioned empirically from the force of natural selection (measured by the natural selection gradient) using partial regression. This measure can be combined with genetic models of interacting phenotypes to provide insights into social evolution.}, } @article {pmid28565400, year = {1998}, author = {Brookfield, JFY}, title = {QUORUM SENSING AND GROUP SELECTION.}, journal = {Evolution; international journal of organic evolution}, volume = {52}, number = {5}, pages = {1263-1269}, doi = {10.1111/j.1558-5646.1998.tb02007.x}, pmid = {28565400}, issn = {1558-5646}, abstract = {Bacteria respond to cell density by expressing genes whose products are beneficial to the population as a whole. This response is brought about through the release into the medium of signaling molecules of the class N-acyl homoserine lactones, the concentration of which determines the level of gene expression. This form of communication between cells has been termed "quorum sensing," and has been found to operate in the control of many functions in a variety of gram-negative bacteria. As with all signaling between individuals, if fitness costs are associated with the release of and response to the signal, the inclusive fitness of alleles responsible for the phenomenon depends upon genetic relatedness between signaler and responder. The situation is considered in explicit models for bacterial population genetics, in which the critical parameter determining the success of quorum sensing is the mean number of cells founding a population sharing a patch of resource. It is found that extensive polymorphism for the presence or absence of quorum sensing is expected for a wide range of parameter space. If local communities of bacteria contain diverse species, community stability may be the consequence of these interactions rather than polymorphism.}, } @article {pmid28565389, year = {1998}, author = {Montague, CE and Oldroyd, BP}, title = {THE EVOLUTION OF WORKER STERILITY IN HONEY BEES: AN INVESTIGATION INTO A BEHAVIORAL MUTANT CAUSING FAILURE OF WORKER POLICING.}, journal = {Evolution; international journal of organic evolution}, volume = {52}, number = {5}, pages = {1408-1415}, doi = {10.1111/j.1558-5646.1998.tb02022.x}, pmid = {28565389}, issn = {1558-5646}, abstract = {Normally, worker honey bees (Apis mellifera) only lay eggs when their colony is queenless. When a queen is present, worker egg-laying is controlled by mutual "policing" behavior in which any rare worker-laid eggs are eaten by other workers. However, an extremely rare behavioral phenotype arises in which workers develop functional ovaries and lay large numbers of eggs despite the presence of the queen. In this study, microsatellite analysis was used to determine the maternity of drones produced in such a colony under various conditions. One subfamily was found to account for about 90% of drone progeny, with the remainder being laid by other subfamilies or the queen. No evidence of queen policing was found. After a one-month period of extreme worker oviposition in spring, the colony studied reverted to normal behavior and showed no signs of worker oviposition. However, upon removal of the queen, workers commenced oviposition very quickly. Significantly, the subfamily that laid eggs when the queen was present did not contribute to the drone production when the colony was queenless. However, another subfamily contributed a disproportionately large number of drones. The frequency of worker oviposition appears to be determined by opposing selective forces. Individual bees benefit from personal reproduction, whereas other bees and the colony are disadvantaged by it. Thus a behavioral polymorphism can be maintained in the population in which some workers can escape worker policing, with balancing selection at the colony level to detect and eliminate these mutations.}, } @article {pmid28565383, year = {1998}, author = {Goodisman, MAD and Ross, KG}, title = {A TEST OF QUEEN RECRUITMENT MODELS USING NUCLEAR AND MITOCHONDRIAL MARKERS IN THE FIRE ANT SOLENOPSIS INVICTA.}, journal = {Evolution; international journal of organic evolution}, volume = {52}, number = {5}, pages = {1416-1422}, doi = {10.1111/j.1558-5646.1998.tb02023.x}, pmid = {28565383}, issn = {1558-5646}, abstract = {We assess nestmate queen relatedness and the genetic similarity of neighboring nests in the polygyne (multiple-queen) social form of the introduced fire ant Solenopsis invicta using both nuclear and mitochondrial markers. We find that estimates of queen relatedness calculated with both types of markers do not differ statistically from zero. Furthermore, there is no significant relationship between the genetic similarity and geographic proximity of nests in each of six study sites. In contrast to these findings, sites show strong mitochondrial, but no nuclear, genetic differentiation. Our results suggest that nonnestmate queen recruitment occurs at a high frequency in introduced populations of this species. Moreover, queens within nests seem to represent a random sample of the queens within the site in which they reside. Therefore, kin selection models that rely on the recruitment of only nestmate queens to explain the persistence of polygyny in ants do not apply to polygyne S. invicta in its introduced range.}, } @article {pmid26197486, year = {1998}, author = {Thiessen, D and Umezawa, Y}, title = {The sociobiology of everyday life : A new look at a very old novel.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {9}, number = {3}, pages = {293-320}, pmid = {26197486}, issn = {1045-6767}, abstract = {The 1000-year-old novel The Tale of Genji, written by Murasaki Shikibu around 1002 CE, shows the operation of general principles of sociobiology. Isolated from western influences and cloaked in Japanese traditions, the common traits associated with reproductive processes are clearly evident. The novel depicts the differential investment of males and females in offspring, male competitive behaviors, and concerns for paternity, kin selection, reciprocal social exchange, species-typical emotional expression, female mate choice, positive assortative mating, and acknowledgment of hereditary transmission of physical and psychological traits. The nature of human behavior in Genji's time seems little different than now and has all the attributes of species-specific and universal traits. Indeed, it can be argued that the fundamental characteristics of Homo sapiens have never changed, being influenced only in form by culture. The qualitative and quantitative evaluation of ancient texts is a strong methodology for understanding the invariant nature of human behavior.}, } @article {pmid26197483, year = {1998}, author = {Smith, EA}, title = {Is tibetan polyandry adaptive? : Methodological and metatheoretical analyses.}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {9}, number = {3}, pages = {225-261}, pmid = {26197483}, issn = {1045-6767}, abstract = {This paper addresses methodological and metatheoretical aspects of the ongoing debate over the adaptive significance of Tibetan polyandry. Methodological contributions include a means of estimating relatedness of fraternal co-husbands given multigenerational polyandry, and use of Hamilton's rule and a member-joiner model to specify how inclusive fitness gains of co-husbands may vary according to seniority, opportunity costs, and group size. These methods are applied to various data sets, particularly that of Crook and Crook (1988). The metatheoretical discussion pivots on the critique by evolutionary psychologists of adaptationist accounts of polyandry. Contrary to this critique, I argue that valid adaptationist explanations of such practices do not necessitate cognitive mechanisms evolved specifically to produce polyandry, nor that there must have been exact equivalents of Tibetan agricultural estates and social institutions in human evolutionary history. Specific issues raised when one posits either kin selection or cultural evolution to explain the adaptive features of Tibetan polyandry are also discussed.}, } @article {pmid28565119, year = {1997}, author = {Frank, SA}, title = {THE PRICE EQUATION, FISHER'S FUNDAMENTAL THEOREM, KIN SELECTION, AND CAUSAL ANALYSIS.}, journal = {Evolution; international journal of organic evolution}, volume = {51}, number = {6}, pages = {1712-1729}, doi = {10.1111/j.1558-5646.1997.tb05096.x}, pmid = {28565119}, issn = {1558-5646}, abstract = {A general framework is presented to unify diverse models of natural selection. This framework is based on the Price Equation, with two additional steps. First, characters are described by their multiple regression on a set of predictor variables. The most common predictors in genetics are alleles and their interactions, but any predictor may be used. The second step is to describe fitness by multiple regression on characters. Once again, characters may be chosen arbitrarily. This expanded Price Equation provides an exact description of total evolutionary change under all conditions, and for all systems of inheritance and selection. The model is first used for a new proof of Fisher's fundamental theorem of natural selection. The relations are then made clear among Fisher's theorem, Robertson's covariance theorem for quantitative genetics, the Lande-Arnold model for the causal analysis of natural selection, and Hamilton's rule for kin selection. Each of these models is a partial analysis of total evolutionary change. The Price Equation extends each model to an exact, total analysis of evolutionary change for any system of inheritance and selection. This exact analysis is used to develop an expanded Hamilton's rule for total change. The expanded rule clarifies the distinction between two types of kin selection coefficients. The first measures components of selection caused by correlated phenotypes of social partners. The second measures components of heritability via transmission by direct and indirect components of fitness.}, } @article {pmid28565095, year = {1997}, author = {Pfennig, DW and Frankino, WA}, title = {KIN-MEDIATED MORPHOGENESIS IN FACULTATIVELY CANNIBALISTIC TADPOLES.}, journal = {Evolution; international journal of organic evolution}, volume = {51}, number = {6}, pages = {1993-1999}, doi = {10.1111/j.1558-5646.1997.tb05120.x}, pmid = {28565095}, issn = {1558-5646}, abstract = {Inclusive fitness theory predicts that organisms can increase their fitness by helping or not harming relatives, and many animals modify their behavior toward kin in a manner consistent with this prediction. Morphogenesis also may be sensitive to kinship environment, particularly in species where certain individuals facultatively develop structures that can be used against conspecifics as weaponry. We tested this hypothesis by examining whether and how consanguinity affected the probability that a structurally distinctive carnivore phenotype, which is opportunistically cannibalistic, would be produced in plains spadefoot toad tadpoles (Spea bombifrons) and southern spadefoot toad tadpoles (S. multiplicata). For tadpoles of S. multiplicata, individuals were significantly more likely to express the carnivore phenotype in mixed sibship groups than in pure sibship groups. For tadpoles of S. bombifrons, individuals were significantly more likely to express the carnivore phenotype when reared alone than in pure sibship groups. Both outcomes were independent of food availability or sibship specific differences in size or growth rate, and waterborne chemical signals from nonkin were sufficient to trigger expression of the carnivore phenotype. Our results suggest that morphogenesis may be responsive to kinship environment in any species or population that occurs as multiple, environmentally induced forms (polyphenism) that differ in their ability to help or to harm others.}, } @article {pmid28565478, year = {1997}, author = {Kelly, JK}, title = {FITNESS VARIATION ACROSS A SUBDIVIDED POPULATION OF THE ANNUAL PLANT IMPATIENS CAPENSIS.}, journal = {Evolution; international journal of organic evolution}, volume = {51}, number = {4}, pages = {1100-1111}, doi = {10.1111/j.1558-5646.1997.tb03957.x}, pmid = {28565478}, issn = {1558-5646}, abstract = {The evolution of a subdivided population depends on whether subpopulations with high mean fitness make a greater per capita contribution to the next generation than subpopulations with lower mean fitness. I distinguish two different models of ecological population structure, denoted local compensation and global compensation. Local compensation restricts the differential contribution of subpopulations, whereas global compensation allows subpopulations to contribute in direct proportion to their mean fitness. I describe a simple regression-based method that distinguishes these alternatives as points on a continuum of possible population structures. The method is applied to field measurements of local abundance and reproduction in a subdivided population of the annual plant Impatiens capensis. These data suggest that the global compensation model is a more accurate description of the population studied. This result is surprising because local density effects on growth and reproduction occur in I. capensis. The implications of ecological population structure for both geographical variation in selection and kin selection are discussed.}, } @article {pmid28307244, year = {1997}, author = {Donohue, K}, title = {Seed dispersal in Cakile edentula var. lacustris : decoupling the fitness effects of density and distance from the home site.}, journal = {Oecologia}, volume = {110}, number = {4}, pages = {520-527}, doi = {10.1007/s004420050189}, pmid = {28307244}, issn = {1432-1939}, abstract = {A factorial design of three densities of siblings at three local distances from seed parents was employed to distinguish effects of density from effects of dispersal distance on lifespan and fruit production of Cakile edentula var. lacustris, a plant with heteromorphic seeds. The segmented fruits produce two seed types: proximal and distal, with distal seeds having greater mass and greater dispersibility. Effects of longer distances (0.5 km and 30 km) on lifespan and fruit production were investigated using plants at low density. The prediction was tested that the greater seed mass of distal seeds increases fitness when seeds are dispersed into sites of unknown quality away from the home site or when seeds are dispersed to low density. High density caused earlier mortality and lower probability of reproduction. Distance from the maternal plant did not influence lifespan or reproduction at distances of 15 m or less, but lifespan was longer 0.5 km from the home site. No interaction was detected between the effects of density and distance on either lifespan or total fitness. Environmental conditions that influence fitness did not vary as a function of dispersal distance in this system, and favorable conditions at the home site did not persist between generations. Therefore, selection on dispersion patterns in natural conditions is likely to be through effects of density rather than dispersal distance. Proximal seeds had greater reproduction than distal seeds at the home site, and distal seeds had greater reproduction at the more distant sites (but not the most distant site), as expected, but these performance differences could not be attributed to differences in mass between the two seed types. Reduced seed mass was favored at the most distant site, but larger seed mass was favored most strongly at low density. Seeds that are dispersed to low density are larger, suggesting that although kin selection may limit the effectiveness of individual selection to increase seed mass under conditions of sibling competition, density-dependent individual selection on seed mass, rather than distant-dependent selection, also contributes to the observed associations among seed type, seed mass and dispersal ability.}, } @article {pmid31940742, year = {1997}, author = {Frank, SA}, title = {Cytoplasmic Incompatibility and Population Structure.}, journal = {Journal of theoretical biology}, volume = {184}, number = {3}, pages = {327-330}, doi = {10.1006/jtbi.1996.0276}, pmid = {31940742}, issn = {1095-8541}, abstract = {Wolbachiais a maternally inherited bacterial infection common in many insects. These bacteria cause cytoplasmic incompatibility, in which a cross between an infected male and an uninfected female is sterile. Infected females are always fertile, suggesting that an infected male produces a sterilizing product against which infected females are protected. This sterility trait is an evolutionary puzzle because it acts in males, but males never transmit the parasites. Previous work has suggested that the parasite gains by reducing the fecundity of uninfected females, thereby increasing the relative reproductive rate of infected females. This argument depends on kin selection effects: the parasite in the male does not reproduce, but can aid related parasites in neighbouring females. Formal population genetic models have failed to confirm the verbal kin selection models. Those models assumed pleiotropic gene action whereby incompatibility evolves as a correlated effect of other fitness components. A formal model presented here supports the original kin selection theories. This new model also suggests an explanation for observed variation in the degree of incompatibility amongWolbachiastrains isolated fromDrosophila simulans.}, } @article {pmid28565652, year = {1996}, author = {Grosberg, RK and Levitan, DR and Cameron, BB}, title = {EVOLUTIONARY GENETICS OF ALLORECOGNITION IN THE COLONIAL HYDROID HYDRACTINIA SYMBIOLONGICARPUS.}, journal = {Evolution; international journal of organic evolution}, volume = {50}, number = {6}, pages = {2221-2240}, doi = {10.1111/j.1558-5646.1996.tb03612.x}, pmid = {28565652}, issn = {1558-5646}, abstract = {Many sedentary, clonal marine invertebrates compete intensively with conspecifics for habitable space. Allorecognition systems mediate the nature and outcome of these intraspecific competitive interactions, such that the initiation of agonistic behavior and the potential for intergenotypic fusion depend strongly on the relatedness of the contestants. The dependence of these behaviors on relatedness, along with the extraordinary precision with which self can be discriminated from nonself, suggest that allorecognition systems are highly polymorphic genetically. However, allotypic specificity of this sort could be produced by any number of genetic scenarios, ranging from relatively few loci with abundant allelic variation to numerous loci with relatively few alleles per locus. At this point, virtually nothing is known of the formal genetics of allorecognition in marine invertebrates; consequently, the evolutionary dynamics of such systems remain poorly understood. In this paper, we characterize the formal genetics of allorecognition in the marine hydrozoan Hydractinia symbiolongicarpus. Hydractinia symbiolongicarpus colonizes gastropod shells occupied by hermit crabs. When two or more individuals grow into contact, one of three outcomes ensues: fusion (compatibility), transitory fusion (a temporary state of compatibility), and rejection (incompatibility, often accompanied by the production of agonistic structures termed hyperplastic stolons). Observed patterns of compatibility between unrelated, half-sib pairs, and full-sib pairs show that unrelated and half-sib pairs under laboratory culture have a very low probability of being fusible, whereas full sibs have a roughly 30% rate of fusion in experimental pairings. The genetic simulations indicate that roughly five loci, with 5-7 alleles per locus, confer specificity in this species. In ecological terms, the reproductive ecology of H. symbiolongicarpus should promote the cosettlement of kin, some of which should be full sibs, and some half sibs. Thus, there is potential for kin selection to play a major role in the evolution of the H. symbiolongicarpus allorecognition system. In genetic terms, this system conforms to theoretical predictions for a recognition system selected to distinguish among classes of kin, in addition to self from nonself.}, } @article {pmid28568938, year = {1996}, author = {Friesen, VL and Montevecchi, WA and Gaston, AJ and Barrett, RT and Davidson, WS}, title = {MOLECULAR EVIDENCE FOR KIN GROUPS IN THE ABSENCE OF LARGE-SCALE GENETIC DIFFERENTIATION IN A MIGRATORY BIRD.}, journal = {Evolution; international journal of organic evolution}, volume = {50}, number = {2}, pages = {924-930}, doi = {10.1111/j.1558-5646.1996.tb03902.x}, pmid = {28568938}, issn = {1558-5646}, } @article {pmid28568848, year = {1996}, author = {Danforth, BN and Neff, JL and Barretto-Ko, P}, title = {NESTMATE RELATEDNESS IN A COMMUNAL BEE, PERDITA TEXANA (HYMENOPTERA: ANDRENIDAE), BASED ON DNA FINGERPRINTING.}, journal = {Evolution; international journal of organic evolution}, volume = {50}, number = {1}, pages = {276-284}, doi = {10.1111/j.1558-5646.1996.tb04491.x}, pmid = {28568848}, issn = {1558-5646}, abstract = {Perdita texana is a facultatively communal bee species with up to 28 females per nest. We used multilocus DNA fingerprinting to test the hypothesis that nestmates are more closely related to each other than are nonnestmates. The mean band sharing proportion among pairwise nestmate comparisons did not differ significantly from the mean among nonnestmate comparisons [P = 0.787 (df = 484)]. Although mean band sharing proportions did not differ among nestmates and nonnestmates, some nestmates show very high band sharing proportions (in excess of the upper 95% confidence limit for the nonnestmate mean). These individuals almost certainly are related, probably as half-sib sisters, however, they comprise a very small percentage of the nestmate populations. Our results indicate that kin selection is unlikely to play an important role in the evolution and maintenance of communal nesting. Communal societies most likely arise because of the mutualistic benefits of cooperative nesting, including accelerated nest founding and improved nest defense.}, } @article {pmid28565077, year = {1995}, author = {Saitω, Y}, title = {CLINAL VARIATION IN MALE-TO-MALE ANTAGONISM AND WEAPONRY IN A SUBSOCIAL MITE.}, journal = {Evolution; international journal of organic evolution}, volume = {49}, number = {3}, pages = {413-417}, doi = {10.1111/j.1558-5646.1995.tb02273.x}, pmid = {28565077}, issn = {1558-5646}, abstract = {Male aggressiveness is highly variable among populations of a subsocial spider mite that occurs throughout Japan. The average level of aggressiveness is positively correlated with mean winter temperature and with the relative size among males of leg I, which is used as a weapon in this species. The relatedness of males within nests is influenced by rates of overwinter survival, with high survivorship leading to low relatedness, increased aggressiveness, and larger legs I. Within this species, variation in the intensity of sexual selection may therefore be influenced both by natural selection and by kin selection.}, } @article {pmid28568006, year = {1993}, author = {Lloyd, DG and Lively, CM}, title = {BRIEF COMMUNICATIONS: COUNTING GENES IN MODELS OF BIPARENTAL INBREEDING.}, journal = {Evolution; international journal of organic evolution}, volume = {47}, number = {6}, pages = {1874-1876}, doi = {10.1111/j.1558-5646.1993.tb01275.x}, pmid = {28568006}, issn = {1558-5646}, } @article {pmid28567772, year = {1992}, author = {Nonacs, P and Tobin, JE}, title = {SELFISH LARVAE: DEVELOPMENT AND THE EVOLUTION OF PARASITIC BEHAVIOR IN THE HYMENOPTERA.}, journal = {Evolution; international journal of organic evolution}, volume = {46}, number = {6}, pages = {1605-1620}, doi = {10.1111/j.1558-5646.1992.tb01157.x}, pmid = {28567772}, issn = {1558-5646}, abstract = {Queens of hymenopteran social parasites manipulate the workers of other social species into raising their offspring. However, nonconspecific brood care may also allow the parasite larvae to control their own development to a greater extent than possible in nonparasitic species. An evolutionary consequence of this may be the loss of the parasite's worker caste if the larvae can increase their fitness by developing into sexuals rather than workers. We argue that this loss is particularly likely in species in which there is little inclusive fitness benefit in working. Retention of a worker caste correlates with characteristics that increase the fitness of working relative to becoming a sexual, such as worker-production of males, high intracolony relatedness, and seasonal environments where the hosts of potential parasite queens are not always available. Further evidence strongly suggests that when the worker caste is evolutionarily lost in perennial species like ants, it disappears rapidly and through a reduction in caste threshold and queen size, so that parasite larvae become queens with less food than required to produce host workers. This evolutionary process, however, appears to lower overall population fitness, resulting in workerless parasite species having small populations and being geographically restricted. Conversely, in annual species like bees and wasps, workerless social parasitism evolves with no size reduction in queens, which is consistent with an expected lower level of queen/offspring conflict.}, } @article {pmid28568999, year = {1992}, author = {Kelly, JK}, title = {RESTRICTED MIGRATION AND THE EVOLUTION OF ALTRUISM.}, journal = {Evolution; international journal of organic evolution}, volume = {46}, number = {5}, pages = {1492-1495}, doi = {10.1111/j.1558-5646.1992.tb01139.x}, pmid = {28568999}, issn = {1558-5646}, abstract = {A suggestion that limited migration, i.e., population viscosity, should favor the evolution of altruism has been challenged by recent kin selection models explicitly incorporating restricted migration. It is demonstrated that these models compound two distinct elements of population structure, spatial-genotypic variation and density regulation. These two characteristics are often determined by distinct biological processes. While they may be linked under certain circumstances, this is not invariably true. A simple modification of the migration system employed in these studies decouples migration and population regulation thus favoring inter-group selection. At least in some cases, restricted migration will facilitate the evolution of altruism.}, } @article {pmid28564031, year = {1992}, author = {Queller, DC}, title = {A GENERAL MODEL FOR KIN SELECTION.}, journal = {Evolution; international journal of organic evolution}, volume = {46}, number = {2}, pages = {376-380}, doi = {10.1111/j.1558-5646.1992.tb02045.x}, pmid = {28564031}, issn = {1558-5646}, abstract = {Inclusive fitness theory is central to our understanding of the evolution of social behavior. By showing the importance of genetic transmission through nondescendent relatives, it helps to explain the evolution of reproductively altruistic behaviors, such as those observed in the social insects. Inclusive fitness thinking is quantified by Hamilton's rule, but Hamilton's rule has often been criticized for being inexact or insufficiently general. Here I show how adopting a genic perspective yields a very general version that remains pleasingly simple and transparent.}, } @article {pmid24222339, year = {1991}, author = {Hill, K and Hurtado, AM}, title = {The evolution of premature reproductive senescence and menopause in human females : An evaluation of the "grandmother hypothesis".}, journal = {Human nature (Hawthorne, N.Y.)}, volume = {2}, number = {4}, pages = {313-350}, pmid = {24222339}, issn = {1045-6767}, abstract = {Reproductive senescence in human females takes place long before other body functions senesce. This fact presents an evolutionary dilemma since continued reproduction should generally be favored by natural selection. Two commonly proposed hypotheses to account for human menopause are (a) a recent increase in the human lifespan and (b) a switch to investment in close kin rather than direct reproduction. No support is found for the proposition that human lifespans have only recently increased. Data from Ache hunter-gatherers are used to test the kin selection hypothesis. Ache data do not support the proposition that females can gain greater fitness benefits in old age by helping kin rather than continuing to reproduce. Nevertheless, one crucial parameter in the model, when adjusted to the highest value within the measured 95% confidence interval, would lead to the evolution of reproductive senescence at about 53 years of age. Further investigation is necessary to determine whether the kin selection hypothesis of menopause can account for its current maintenance in most populations.}, } @article {pmid28568819, year = {1991}, author = {Blows, MW and Schwarz, MP}, title = {SPATIAL DISTRIBUTION OF A PRIMITIVELY SOCIAL BEE: DOES GENETIC POPULATION STRUCTURE FACILITATE ALTRUISM?.}, journal = {Evolution; international journal of organic evolution}, volume = {45}, number = {3}, pages = {680-693}, doi = {10.1111/j.1558-5646.1991.tb04338.x}, pmid = {28568819}, issn = {1558-5646}, abstract = {Exoneura bicolor is a univoltine, facultatively social bee exhibiting a solitary/quasisocial/semisocial colony polymorphism (Schwarz, 1986, 1987). Intracolony relatedness in semisocial colonies has been previously estimated at 0.49 ± 0.06 (Schwarz, 1987), although the crucial relatedness between altruists and the brood that they rear will be about half this value. This value is unlikely to be increased by the preferential rearing of only close relatives (Schwarz, 1988a) and no known morphological specializations preclude workers from reproducing in this species. Hamilton (1972, 1975) suggested that relatedness may be increased through population subdivision, if this leads to significant inbreeding and increased between-colony genetic variance. The same process may also operate at higher levels of population structure (e.g., Wade, 1978). Population structure and intracolony relatedness in E. bicolor were investigated in seven localities in southern Victoria, Australia, to determine if inbreeding at any level of population structure was contributing to relatedness between altruists and beneficiaries within these colonies. Population structure was described using hierarchical F-statistics and an identity by descent measure, developed by Queller and Goodnight (1989), was used to estimate intracolony relatedness. It was found that inbreeding was not contributing to between-group genetic variance, at any level, in a consistent manner across localities. Therefore relatedness, considered in isolation, does not seem sufficient to account for the presence of worker behavior. It is suggested that large benefits for group living may be responsible for maintaining altruistic behavior, in part, in this species. Significant heterogeneity among localities for all F-statistics estimated in our analysis was found and this may be attributable to stochastic elements such as cofounding behavior and the low percentage of males in the brood. The possible consequences of such heterogeneity in population structure for the maintenance of altruism in E. bicolor are discussed.}, } @article {pmid28564435, year = {1990}, author = {Anderson, DJ}, title = {EVOLUTION OF OBLIGATE SIBLICIDE IN BOOBIES. 2: FOOD LIMITATION AND PARENT-OFFSPRING CONFLICT.}, journal = {Evolution; international journal of organic evolution}, volume = {44}, number = {8}, pages = {2069-2082}, doi = {10.1111/j.1558-5646.1990.tb04312.x}, pmid = {28564435}, issn = {1558-5646}, abstract = {Proximate limitation on parental food delivery has long been invoked to explain the evolution of single-chick broods of pelagic seabirds such as masked boobies (Sula dactylatra). A second possible proximate limit on brood size is siblicide driven by genetic parent-offspring conflict (POC) over brood size, if siblicidal offspring can reduce brood size to one even if the parents' optimal brood size is greater than one. I tested these two hypotheses by experimentally suppressing obligate siblicide in masked booby broods and comparing breeding parameters of these broods with unmanipulated single-chick control broods. Per capita mortality rate of experimental nestlings was higher than that of controls, but this deficit was more than made up by larger brood size. Parents of experimental broods brought more food to offspring, had higher fledging success, and apparently incurred no additional major short-term cost of reproduction, relative to parents of control broods, thus refuting the food limitation hypothesis. Estimates of inclusive fitness of chicks in experimental broods were higher than were those of control nestlings, a result inconsistent with the POC hypothesis that the siblicidal offspring's optimal brood size is one while the parents' optimum is greater than one. This discrepency between natural brood size and apparent brood size optima might be resolved in several ways: experimental artifacts may give misleading estimates of optimal brood size; experimental and control offspring may have different reproductive values at the time of fledging; nestling masked boobies may face a special frequency-dependent case of POC in which the high risk of sharing a nest with a siblicidal sibling makes invasion of other behavioral genotypes difficult even when offspring and parent inclusive fitnesses are higher from a nonsiblicidal brood of two than from a brood of one.}, } @article {pmid28312770, year = {1990}, author = {Zammit, C and Zedler, PH}, title = {Seed yield, seed size and germination behaviour in the annualPogogyne abramsii.}, journal = {Oecologia}, volume = {84}, number = {1}, pages = {24-28}, pmid = {28312770}, issn = {1432-1939}, abstract = {Models of the evolution of seed dormancy reveal that dormancy is favoured either when opportunities for establishment vary over time and when there is wide variation in the probability of success, or when the probability of success is limited by frequency dependence. Empirical evidence supporting the temporal heterogeneity hypothesis exists, but there is scant evidence for dormancy being favoured by frequency dependent competition among seedlings. We test the hypothesis that the intensity of between-sib competition should favour a positive relationship between maternal fecundity and seed dormancy. This hypothesis is supported for the rare, vernal pool annual,Pogogyne abramsii: the proportion of dormant offspring was significantly higher among high fecundity mothers than among other mothers. Dormancy inP. abramsii is controlled by the seed coat, a maternal tissue, so delaying germination favours the inclusive fitness of mothers by reducing the potential for competition among siblings. Seed weight and time to first germination varied significantly amongP. abramsii plants and mean seed weight increased linearly with plant biomass. Seed weight and seed number are independently regulated by plant size. Overall, seed weight varied 10-fold and variability in seed weight within mothers was not explained by plant biomass, seed yield or mean seed weight. GerminableP. abramsii seeds were significantly heavier than dormant seeds, and germinable seeds heavier than 0.20 mg germinated more rapidly than those smaller than 0.20 mg.}, } @article {pmid28569035, year = {1990}, author = {Boomsma, JJ and Grafen, A}, title = {INTRASPECIFIC VARIATION IN ANT SEX RATIOS AND THE TRIVERS-HARE HYPOTHESIS.}, journal = {Evolution; international journal of organic evolution}, volume = {44}, number = {4}, pages = {1026-1034}, doi = {10.1111/j.1558-5646.1990.tb03823.x}, pmid = {28569035}, issn = {1558-5646}, abstract = {We consider worker-controlled sex investments in eusocial Hymenoptera (ants in particular) and assume that relatedness asymmetry is variable among colonies and that workers are able to assess the relatedness asymmetry in their own colony. We predict that such "assessing" workers should maximize their inclusive fitness by specializing in the production of the sex to which they are relatively most related, i.e., colonies whose workers have a relatedness asymmetry below the population average should specialize in males, whereas colonies whose workers have a higher than average relatedness asymmetry should specialize in making females. Our argument yields the expectation that colony sex ratios will be bimodally distributed in ant populations where relatedness asymmetry is variable owing to multiple mating, worker reproduction, and/or polygyny. No such bimodality is expected, however, in ant species where relatedness asymmetry is known to be constant, or in cases where relatedness asymmetry is supposed to be irrelevant due to allospecific brood rearing under queen control, as in the slave-making ants. Comparative data on colony sex ratios in ants are reviewed to test the predictions. The data partly support our contentions, but are as yet insufficient to be considered as decisive evidence.}, } @article {pmid28313003, year = {1990}, author = {Ylönen, H and Mappes, T and Viitala, J}, title = {Different demography of friends and strangers: an experiment on the impact of kinship and familiarity in Clethrionomys glareolus.}, journal = {Oecologia}, volume = {83}, number = {3}, pages = {333-337}, pmid = {28313003}, issn = {1432-1939}, abstract = {We examined demographic effects of familiarity and relatedness in the bank vole Clethrionomys glareolus (Schreber) in four 0.5-ha enclosures in Central Finland. In two enclosures were mature voles which had overwintered together and some of their mature off-spring (hereafter referred to as "Friends"), and in the other two individuals of the same species captured from different localities near the study area ("Strangers"). The experiment lasted from June to September. The populations of Friends reached densities twice as high as those of Strangers with a significantly higher rate of recruitment and survival of the young. This may have been due to mutual familiarity decreasing antagonism towards the juveniles. The conflicting results obtained from studies of Clethrionomys and Microtus are discussed. We believe that these genera represent behavioural adaptations to different habitats and ways of life. Most behavioural population regulation hypotheses are based on studies of Microtus. We conclude that these results should be applied with great caution to other rodent genera.}, } @article {pmid33873979, year = {1990}, author = {Raven, JA and Franco, AA and de Jesus, EL and Jacob-Neto, J}, title = {H[+] extrusion and organic-acid synthesis in N2 -fixing symbioses involving vascular plants.}, journal = {The New phytologist}, volume = {114}, number = {3}, pages = {369-389}, doi = {10.1111/j.1469-8137.1990.tb00405.x}, pmid = {33873979}, issn = {1469-8137}, abstract = {An analysis of published data suggests that the N2 -fixing symbiotic vascular plants extrude more H[+] per unit N fixed than would be expected from data on the same genotypes growing on NH4 [+] if the plants had the same chemical composition when grown on the two N sources. The H[+] /N ratio with urea as the N source is similar to that with N2 . The higher H[+] /N ratio and higher organic acid/N ratio with N2 or urea as N source implies higher whole-plant energy and water costs per unit of biomass and, ultimately, inclusive fitness, produced. The rhizosphere acidification resulting from H[+] extrusion may serve to change rhizosphere pH to some 'optimal' value, and to increase the availability of such limiting resources as P, Mo and Fe which are especially needed in diazotrophy. Data in the literature are consistent with these possibilities in the few cases examined. Within the plant, data on xylem and phloem sap composition in conjunction with shoot composition, of diazotrophically-growing legumes suggest that shoot acid-base homoiostasis can be maintained via the import of appropriate solutes in the xylem and the export of appropriate solutes in the phloem. Acid-base regulation of the nodules in the absence of any H[+] exchange with their environment can also probably be explained in terms of the solutes supplied in the phloem and exported in the xylem. This conclusion is based on data in the literature on the composition of stem phloem sap and of xylem sap exuding from detached nodules of diazotrophic vascular plants. These considerations do not exclude the possibility of net H[+] efflux from nodules fixing N2 in contact with an aqueous medium. The limited data available are consistent with extrusion of some of the H[+] generated in nodules as an alternative to their neutralization by metabolism of organic anions entering in the phloem. Such H[+] extrusion by nodules could aid in their acquisition of Fe from the medium, albeit not always at a phase in the life or the nodule when there is a net requirement for Fe.}, } @article {pmid28568393, year = {1989}, author = {Grosberg, RK and Quinn, JF}, title = {THE EVOLUTION OF SELECTIVE AGGRESSION CONDITIONED ON ALLORECOGNITION SPECIFICITY.}, journal = {Evolution; international journal of organic evolution}, volume = {43}, number = {3}, pages = {504-515}, doi = {10.1111/j.1558-5646.1989.tb04248.x}, pmid = {28568393}, issn = {1558-5646}, abstract = {Many sessile cnidarians deploy specialized structures while competing aggressively for living space. The initiation of aggression is often contingent on the relatedness of the interacting contestants; clonemates and close kin generally behave passively toward one another, whereas more distant relatives generally behave aggressively. Behavioral specificity of this sort requires that there be 1) an allorecognition system that can discriminate among subtle differences in cell-surface determinants and 2) a highly polymorphic genetic system that provides specific labels of relatedness (haplotypes or allotypes). The evoutionary models analyzed in this paper show that a population of individuals that behave aggressively only against haplotypically distinct individuals (discriminating phenotypes) will not be evolutionarily stable in the face of either unconditionally aggressive or unconditionally nonaggressive phenotypes. Furthermore, even if the discriminating trait were somehow fixed, the rare recognition alleles necessary to confer allotypic specificity could not become established through natural selection. Thus, allotypic specificity is unlikely to be maintained by individual selection acting directly through aggressive behavior. Other selective mechanisms might account for the evolution of allorecognition specificity. Allotypic polymorphism could be maintained by pleiotropic mechanisms in which rare alleles are favored by natural selection acting either on gametic incompatibility, pathogen resistance, or somatic fusion, rather than aggressive behavior per se. However, these mechanisms do not explain the maintenance of selective aggression based on allotypic differences. Alternatively, if aggressive members of a clone indirectly enhance the reproductive output or survival of the entire clone (or close relatives), then kin selection acting directly through aggressive behavior could favor allorecognition specificity. Choosing among these alternatives will require the development of more sophisticated theory and empirical analyses of the costs and benefits of aggression.}, } @article {pmid28311959, year = {1988}, author = {Jasieński, M}, title = {Kinship ecology of competition: size hierarchies in kin and nonkin laboratory cohorts of tadpoles.}, journal = {Oecologia}, volume = {77}, number = {3}, pages = {407-413}, pmid = {28311959}, issn = {1432-1939}, abstract = {This study provides an experimental test of the ecological significance of kinship in competitive interactions among individuals. Tadpoles of the fire-bellied toad, Bombina variegata (Anura, Discoglossidae) reared in the laboratory in a high density of siblings grew better and developed faster than when they were reared with similar densities of nonrelatives. Kinship-based genotypic uniformity may therefore be advantageous: it can lead to faster and more uniform growth. In nature it may well be kin recognition that permits such advantage to be realised. The largest tadpoles from pure-sibship cohorts accounted, on average, for the smaller fraction of the cohort total biomass than the largest tadpoles reared with cohorts of nonrelatives, although they attained the same absolute weight and developmental stage. The smallest individuals from pure-sibship cohorts had a much larger absolute body weight than the smallest tadpoles from mixed-sibship cohorts, and were also much more advanced developmentally. The results could be an effect of an altruistic restraint in growth rate on the part of the largest tadpoles in sibling cohorts and certainly not of the smallest ones. However, the results could also be due to the altruism-independent facilitation of living conditions in pure-sibship groups, resulting solely from potential advantages of homogeneous water conditioning.}, } @article {pmid28312321, year = {1988}, author = {Boonstra, R and Hogg, I}, title = {Friends and strangers: a test of the Charnov-Finerty Hypothesis.}, journal = {Oecologia}, volume = {77}, number = {1}, pages = {95-100}, pmid = {28312321}, issn = {1432-1939}, abstract = {We tested the hypothesis that populations composed of unrelated animals should perform worse than those composed of related animals by setting up two moderatedly dense field populations in adjacent enclosures: one was composed of related females and one of unrelated females; both had unrelated males. The survival and reproductive success of a number of litters located by spooling were determined. Final population size, pregnancy success, number of young recruited per pregnancy, and survival were similar in both populations. Thus, differences in relatedness produced no differences in demography. We conclude that the Charnov-Finerty Hypothesis in unlikely to be an explanation for microtine population fluctuations.}, } @article {pmid28564012, year = {1988}, author = {Nonacs, P}, title = {QUEEN NUMBER IN COLONIES OF SOCIAL HYMENOPTERA AS A KIN-SELECTED ADAPTATION.}, journal = {Evolution; international journal of organic evolution}, volume = {42}, number = {3}, pages = {566-580}, doi = {10.1111/j.1558-5646.1988.tb04161.x}, pmid = {28564012}, issn = {1558-5646}, abstract = {Using a series of kin-selection models, I examine factors that favor multiple egg-laying queens (polygyny) in eusocial Hymenoptera colonies. One result is that there is a theoretical conflict of interest between the founding queens and their daughter workers over how many and which individuals should be the extra reproductives. Both castes should prefer their full sisters. Therefore, primary polygyny (multiple related foundresses) may favor queens while secondary polygyny (related queens added to mature colonies) may favor workers. Polygyny, itself, was found to be favored by high colony survivorship and low probability of queens contributing eggs to successive broods. Polygyne colonies, however, did not need to produce more offspring per brood to be selectively favored; they could be half as productive per brood as monogyne ones and still have higher lifetime fitness under some conditions. For reproductive data from eight ant species with both monogyne and polygyne colonies, the model generates results that are consistent with a kin-selection explanation of polygyny in all of them. It is proposed that queen number is an ecologically flexible trait that is influenced by a broad set of factors but is not necessarily linked to specific habitat types. Furthermore, neither polygyny nor monogyny may be reliably considered as the primitive or ancestral Hymenopteran social system. The optimal queen number within a species may evolutionarily increase or decrease, depending on the direction of environmental change.}, } @article {pmid28567849, year = {1988}, author = {Sillén-Tullberg, B}, title = {EVOLUTION OF GREGARIOUSNESS IN APOSEMATIC BUTTERFLY LARVAE: A PHYLOGENETIC ANALYSIS.}, journal = {Evolution; international journal of organic evolution}, volume = {42}, number = {2}, pages = {293-305}, doi = {10.1111/j.1558-5646.1988.tb04133.x}, pmid = {28567849}, issn = {1558-5646}, abstract = {Gregariousness ought to be disadvantageous for palatable organisms that live exposed and are relatively immobile and small in comparison to potential predators. Therefore, the idea that unpalatability generally evolves before egg clustering/larval gregariousness in butterflies was tested. Aposematic coloration in the larva was used as the criterion of unpalatability (it is argued that Batesian mimicry is rare in butterfly larvae), and the relative order of evolution of aposematism and gregariousness was inferred through phylogenetic analysis. Here, existing phylogenies were used, and the analysis was based on an assumption of a minimum number of evolutionary changes (parsimony). A total of 23 cases of independent evolution of gregariousness and 12 cases of independent evolution of aposematic coloration were found. In five cases, gregariousness evolved in cryptic species, the palatability of which is unknown. For lineages in which both unpalatability, as evidenced by aposematic coloration, and gregariousness were found and the two evolutionary events could be separated, unpalatability always preceded gregariousness: five cases of independent evolution of warning coloration were followed by a total of 15 cases of independent evolution of gregariousness. In no lineage did gregariousness evolve before warning coloration. It is thus concluded that unpalatability is an important predisposing factor for the evolution of egg clustering and larval gregariousness in butterflies. Insofar as kin selection is related to larval gregariousness, this study indicates that kin selection is of minor importance for the evolution of both unpalatability and warning coloration.}, } @article {pmid28563857, year = {1988}, author = {Roeloffs, R and Riechert, SE}, title = {DISPERSAL AND POPULATION-GENETIC STRUCTURE OF THE COOPERATIVE SPIDER, AGELENA CONSOCIATA, IN WEST AFRICAN RAINFOREST.}, journal = {Evolution; international journal of organic evolution}, volume = {42}, number = {1}, pages = {173-183}, doi = {10.1111/j.1558-5646.1988.tb04117.x}, pmid = {28563857}, issn = {1558-5646}, abstract = {Dispersal experiments and gel electrophoresis of allozyme polymorphisms were used to investigate the selective mode underlying cooperative behavior in the rainforest spider, Agelena consociata. Previous work has indicated that individual selection alone does not explain the cooperative and even altruistic behavior noted for this African species, which exists in groups of up to hundreds of adults. We found no evidence for active dispersal by reproductives or any age class of this spider. Nest fragmentation by falling tree limbs and storms is indicated as the cause of new nest formation within local areas, while passive dispersal by vertebrate carriers that either have some association with the nests (bats) or move through them is indicated as the probable mode of longer-distance dispersal. The population-genetic structure observed for A. consociata supports the data obtained on dispersal. Wright's FST statistic and G tests for genetic heterogeneity indicate that the populations are subdivided into genetically heterogeneous colonies. Comparisons utilizing Nei's genetic distance show colonies separated by as few as 30 m to be as genetically distinct as are colonies separated by many kilometers. There is also a marked scarcity of heterozygotes, and individuals within nests and associated colonies are genetically related about as much as are full siblings. The results of these analyses indicate that kin selection or some type of family-group selection may have been important in the evolution of cooperative behavior in the species.}, } @article {pmid28563840, year = {1988}, author = {van der Have, TM and Boomsma, JJ and Menken, SBJ}, title = {SEX-INVESTMENT RATIOS AND RELATEDNESS IN THE MONOGYNOUS ANT LASIUS NIGER (L.).}, journal = {Evolution; international journal of organic evolution}, volume = {42}, number = {1}, pages = {160-172}, doi = {10.1111/j.1558-5646.1988.tb04116.x}, pmid = {28563840}, issn = {1558-5646}, abstract = {The genetic variation at two marker loci in three populations of the monogynous ant Lasius niger was used to analyze the importance of relatedness structure to sex-investment ratios in sexuals produced by colonies living in different resource conditions. From a resource-rich monoculture to a population in a resource-limited environment, dry weight investment in queens decreased from female-biased (0.76) to equality with male investment (Boomsma et al., 1982). The investment ratios in sexuals expected from the estimated relatedness ratios, resulting from kin-selection theory (Trivers and Hare, 1976), were in good agreement with the observed ratios in all populations. This indicated that the workers can capitalize on the asymmetry in relatedness, opposing the queen's interest, despite the contrast in environmental conditions in the different populations. This asymmetry, however, almost disappeared in the marginal population, due to a high frequency of double mating and worker production of males, resulting in a much reduced queen-worker conflict. We suggest that different levels of polyandry might be favored at different points of the resource gradient, with the sex ratio secondarily depending on these polyandry levels. As there was no population subdivision or spatial structure within the populations, group-selection and local-mate-competition models cannot account for the observed female-biased ratios, whereas they were rather accurately predicted by kin-selection theory.}, } @article {pmid28564347, year = {1987}, author = {Crozier, RH and Smith, BH and Crozier, YC}, title = {RELATEDNESS AND POPULATION STRUCTURE OF THE PRIMITIVELY EUSOCIAL BEE LASIOGLOSSUM ZEPHYRUM (HYMENOPTERA: HALICTIDAE) IN KANSAS.}, journal = {Evolution; international journal of organic evolution}, volume = {41}, number = {4}, pages = {902-910}, doi = {10.1111/j.1558-5646.1987.tb05863.x}, pmid = {28564347}, issn = {1558-5646}, abstract = {Lasioglossum zephyrum is a primitively eusocial bee, which nests in small colonies of up to 20 individuals. The nests occur in patchily distributed aggregations of from a few to over 1,000 nests along periodically disturbed stream and river banks in eastern North America. We used five polymorphic allozyme loci to test for geographic structure and estimate relatedness in eight patches of nests from five aggregations in Douglas Co., Kansas. Autocorrelation analysis of gene frequencies, plus a multilocus G test, revealed a low but significant tendency for differentiation among nests within patches, among patches within aggregations, and among aggregations. Small numbers of nests restricted estimation of relatedness to three patches, of which only one had a sample size large enough to yield confidence limits narrow enough to be informative. The limits from this patch of 20 nests are 0.64 < 0.8245 < 1.01. While these limits are consistent with the true value being 0.75 (that expected under male-haploidy if each nest results from the reproduction of a single, once-mated female), the occurrence of some nests with three or more genotypes shows that nest makeup is more complex than this, so that a lower value, say 0.7, is more plausible. This value is sufficiently high to indicate that kin selection is probably important in these populations.}, } @article {pmid24896865, year = {1987}, author = {Thompson, RK and Liebreich, M}, title = {Adult chicken alarm calls enhance tonic immobility in chicks.}, journal = {Behavioural processes}, volume = {14}, number = {1}, pages = {49-61}, doi = {10.1016/0376-6357(87)90066-0}, pmid = {24896865}, issn = {0376-6357}, abstract = {An experimenter induced tonic immobility (TI) in parentally naive chicks (G. gallusdomesticus). The chicks remained in TI longer when they were exposed to a conspecific adult fear squawk alarm call than when exposed to an equally novel attraction call or white noise. In a second experiment, both aerial-predator and ground-predator alarm calls enhanced TI similarly to the fear squawk call which is elicited by capture. These results support the hypotheses that TI is an antipredator defense mechanism and that alarm calls evolved through kin-selection.}, } @article {pmid24301365, year = {1987}, author = {Muhtasib, H and Evans, DL}, title = {Linamarin and histamine in the defense of adultZygaena filipendulae.}, journal = {Journal of chemical ecology}, volume = {13}, number = {1}, pages = {133-142}, pmid = {24301365}, issn = {0098-0331}, abstract = {We determined the protective values of histamine and linamarin to an aposematic moth,Zygaena filipendulae. Using ion-exchange resin techniques, we found that the mean histamine concentrations in the wings were 0.061 ± 0.047 μg/mg and 0.013 ± 0.0051 in the moths' bodies (totals: 0.586 μg and 2.921 μg, respectively, all wet weights). Average HCN evolution (mainly from the bitter cyanogen linamarin) from the wings was 0.049 ± 0.41 μg/mg (0.426 μg/ml of linamarin could produce this amount of HCN) and 0.029 ± 0.0026 μg/mg HCN (0.281 μg/mg linamarin) evolved from the bodies (total linamarin 4.09 μg and 61.258 μg, respectively, all wet weights). Therefore, higher concentrations of toxicants were found in the part of the body most liable to initial attack. We found, in offering various toxic solutions to 10 common quails, that 0.1% linamarin (mean linamarin consumed equal to about 70% of the average total wing content) but 1.0% histamine (mean histamine consumed equal to that found in about 8.9 average wing sets) solutions significantly lowered drinking rates. However, combination solutions were still effectively aversive at 0.001% histamine plus 0.028% linamarin. This synergism would allow a moth under local abiotic or dietary stress to elaborate substantially less of one or both compounds than that normally synthesized. The implications to kin selection are discussed.}, } @article {pmid28556332, year = {1986}, author = {Chesser, RK and Ryman, N}, title = {INBREEDING AS A STRATEGY IN SUBDIVIDED POPULATIONS.}, journal = {Evolution; international journal of organic evolution}, volume = {40}, number = {3}, pages = {616-624}, doi = {10.1111/j.1558-5646.1986.tb00512.x}, pmid = {28556332}, issn = {1558-5646}, abstract = {A generalized expression for coefficients of consanguinity and relationship with previous inbreeding is presented to examine various breeding strategies in subdivided populations. Conditions that would favor inbreeding are developed for: 1) nonfamilial inbreeding within a deme versus outbreeding; 2) altruistic inbreeding by females versus outbreeding; 3) sib-mating versus outbreeding; and 4) sib-mating versus nonfamilial breeding within a deme. Inbreeding behavior is advantageous under certain conditions but depends on the types of mating, the previous breeding history of the deme, the rate of accumulation of inbreeding depression, and the cost of migration. In polygynous mating systems it is genetically more advantageous for males to migrate, because female emigration may 1) leave a related male with no mate or one fewer mate, or 2) force both male and female to risk the cost of migration. Nonfamilial breeding is always a better strategy than sib-mating given previous inbreeding within the deme. Even when the cost of migration is zero, inbreeding is favored if the coefficient of relationship among relatives is greater than the ratio of the probabilities of offspring inviability to offspring viability. Although high inbreeding coefficients are probably not adaptive unless the costs of migration are great or inbreeding depression constants are small, low levels of inbreeding are advantageous in many situations. Therefore, increased genetic representation by way of inbreeding and inclusive fitness is a major component of the evolutionary process.}, } @article {pmid28556322, year = {1986}, author = {Mock, DW and Parker, GA}, title = {ADVANTAGES AND DISADVANTAGES OF EGRET AND HERON BROOD REDUCTION.}, journal = {Evolution; international journal of organic evolution}, volume = {40}, number = {3}, pages = {459-470}, doi = {10.1111/j.1558-5646.1986.tb00499.x}, pmid = {28556322}, issn = {1558-5646}, abstract = {Data from great egrets and great blue herons were used to test a fundamental assumption of Lack's brood-reduction hypothesis, that mortality is brood-size dependent. This was confirmed for the largest brood sizes (4 and 3), which, in egrets, also have the highest sib-fighting rates. Broods of one, however, experienced paradoxically high mortality, especially early in the season. The hypothesis is advanced that parents desert unprofitably small broods when sufficient time remains for production of a larger brood. A simple game-theory model shows that this parental desertion may hinge primarily on the overall costs of renesting. Egret brood reduction caused by sibling aggression (siblicide) occurred later than less aggressive forms of brood reduction. The inclusive fitness of senior broodmates is maximized by the successful fledging of all sibs, and the physical superiority of seniors (in food-handling for herons; food-handling and aggression for egrets) usually suffices to guarantee their own welfare in brood competitions. Finally, it is shown that the last chick in asynchronously hatching broods represents two kinds of reproductive value (RV) to the parents-"extra RV" (obtained despite the survival of elder sibs) and "insurance RV" (obtained only when at least one elder sib dies first)-which can be distinguished from field data. This approach can be used in comparisons with other asynchronous species for partitioning the fitness contributions of marginal offspring.}, } @article {pmid28564119, year = {1986}, author = {Morris, DW}, title = {PROXIMATE AND ULTIMATE CONTROLS ON LIFE-HISTORY VARIATION: THE EVOLUTION OF LITTER SIZE IN WHITE-FOOTED MICE (PEROMYSCUS LEUCOPUS).}, journal = {Evolution; international journal of organic evolution}, volume = {40}, number = {1}, pages = {169-181}, doi = {10.1111/j.1558-5646.1986.tb05728.x}, pmid = {28564119}, issn = {1558-5646}, abstract = {Recruitment of litter-mates of nest-box-inhabiting white-footed mice was monitored to study the evolution of litter size. The frequency distribution of litter sizes was nonsymmetrical, and the most frequent litter size was less than the optimum. This was not the result of differential parental survival, which was independent of litter size produced. Recruitment remained constant or increased slightly to a peak in litters of five young, and then dropped precipitously for larger litters. The single optimum litter size of five did not appear to have any physiological correlates. Instead, the equally low probability of successful recruitment of any young from any given litter may have given rise to a bet-hedging strategy of frequent iterated reproductions. A theoretical analysis of optimal parental investment in offspring was initiated under the assumption that optimal brood size represents a maximization of differences between age-specific costs and benefits of reproduction, both of which should be measured in constant currency of inclusive fitness. In the past, benefit has been measured by current fecundity, and cost by residual reproductive value. However, reproductive value is an appropriate estimate of inclusive fitness only for organisms in which parental investment has little effect on the subsequent survival of offspring to reproductive age. Reproductive value weighted by offspring survival and devalued by the degree of genetic relatedness defines a new currency, replacement value, which is more appropriate for evaluating the costs and benefits of parent-offspring conflict over parental investment in current as opposed to future young. Total parent-offspring conflict intensifies with increases in current brood size. For species with severe reproductive constraints, such as post-partum estrus in white-footed mice, such conflict may force parents to curtail investment in current offspring at or near parturition of subsequent litters, even if that means reducing the survival of current young.}, } @article {pmid28310129, year = {1986}, author = {Mallet, J}, title = {Dispersal and gene flow in a butterfly with home range behavior: Heliconius erato (Lepidoptera: Nymphalidae).}, journal = {Oecologia}, volume = {68}, number = {2}, pages = {210-217}, pmid = {28310129}, issn = {1432-1939}, abstract = {Heliconius butterflies have been found to have low rates of dispersal in previous mark-recapture studies, and this lack of movement is due home-range behavior. An experiment on Heliconius erato was designed to investigate movement from the site of pupal eclosion. It was found that most of the movement occurs before the first capture of an individual in a mark-recapture study. After incorporating this early movement, the dispersal parameter, σ, is estimated to be at least 296 m (±30 m jackknifed standard error), and the "neighborhood population size", N, is about 50-150 individuals. These estimates of σ and N are more than 2 and 5 times larger, respectively, than estimates based on standard mark-recapture data, though they are small compared with estimates from other butterfly species. Severe limitations of using dispersal experiments to estimate gene flow and neighborhood size are discussed. Genetic data from color pattern loci in hybrid zones and from electrophoresis suggest that, if anything, the estimates of σ and N that I have obtained are still too low. Genetic and dispersal data together show that kin selection is an unlikely mechanism for the evolution of warning color and other supposed altruisms in Heliconius, unless occasional genetic drift is also involved.}, } @article {pmid33873830, year = {1985}, author = {Raven, JA}, title = {TANSLEY REVIEW No. 2: REGULATION OF PH AND GENERATION OF OSMOLARITY IN VASCULAR PLANTS: A COST-BENEFIT ANALYSIS IN RELATION TO EFFICIENCY OF USE OF ENERGY, NITROGEN AND WATER.}, journal = {The New phytologist}, volume = {101}, number = {1}, pages = {25-77}, doi = {10.1111/j.1469-8137.1985.tb02816.x}, pmid = {33873830}, issn = {1469-8137}, abstract = {The benefits which this paper addresses are those of maintaining the intracellular acid-base balance during growth, and of generating osmolarity related to regulation of turgor in environments of low water potential. These benefits may incur costs in terms of the quantity of potentially growth-limiting resources (photons, water, nitrogen) which are needed to produce unit quantity of 'baseline' plant biomass. The direction (excess H[+] or excess OH[-]) and magnitude of acid-base perturbation during growth depends on the nature of the N-source (NH4 [+] , N2 or NO3 [-]), so that the costing of pH homoiostasis involves consideration of the costs of overall N-assimilation for comparison with the other costs of growth of a terrestrial C3 plant. Photon costs for the various biochemical and transport processes involved in overall growth, N-assimilation, pH regulation and osmolarity generation are computed using known stoichiometries of coupled reactions. Water costs are deduced from the C-requirements for the various processes (including C lost in associated decarboxylations) by assuming a constant value of water lost in transpiration per unit net C fixed in an illuminated shoot. Nitrogen costs are deduced from the N-content of the plants or compounds under consideration. The computed costs for N-assimilation and the generation of osmolarity are referred to the costs of 'baseline' plant synthesis using the cheapest mechanisms (NH4 [+] as source for N-assimilation; inorganic ions as the basis for osmolarity generation) so that the increment of cost related to assimilation of N2 or NO3 [-] , or of osmolarity generation using an organic compatible solute, can be presented. Photon costs of growth with N2 fixation and the processes associated with regulation of pH are (granted the assumptions made as to stoichiometries and plant composition) 9 % higher than are those of growth with NH4 [+] as N˜ source. The predicted cost of growth with NO3 [-] as N source depends on the location of NO3 [-] reduction and the mechanism of OH[-] disposal, and ranges from 5 to 12% more than that for growth with NH4 [+] as N source. H2 O (transpiration) costs follow a similar pattern, with growth on N2 as N source costing 12% more, and growth on NO3 [-] costing to 1-2 to 167 % more, than growth with NH4 [+] as N source. The extra costs in photons of using compatible solutes (sorbitol, proline or glycine betaine) to generate an osmolarity of 500 osmol m[-3] in all of the non-apoplastic water of the plant add 21·5 to 26·1 % to the total costs of growth, while use of compatible solutes to generate osmolarity in 'N' phases (i.e. cytosol, plastid stroma, mitochondrial matrix) alone would add 5·2 to 6·2% The costs of growth in terms of transpirational water are increased 7·9 to 98 % by the use of compatible solutes for osmolarity generation in the 'N' phases only. The increments for the N-containing solutes are higher when NO3 [-] is the N-source rather than NH4 [+] . The N-cost of growth with N-containing compatible solutes generating 500 osmol m[-3] in 'N' phases increases the N cost of growth by 33%. These predicted costs are under-estimates of 'real' costs which take into account the occurrence of alternate oxidase activity under some growth conditions and the production of additional organic acid anions with N2 as opposed to NH4 [+] as N source. Nevertheless, the predicted minimum costs of attaining the benefits of pH regulation and of turgor generation are of use in suggesting where selectively significant (i.e. low requirement for a scarce resource) alternative mechanisms may occur. Examples include a possible photon saving by using NH4 [+] rather than N2 or NO3 [-] where all three are available; a possible water saving by use of photoreduction of NO3 [-] in leaves in arid environments; and a possible N saving by use of non-N-containing compatible solutes (polyols) in environments of low water potential. Proof of these suggestions involves comparisons of inclusive fitness of genotypes possessing the trait under consideration with that of genotypes lacking the trait. CONTENTS Summary 26 I. Introduction 27 II. pH Regulation and Osmolarity Generation 27 III. Photon Costs of Various Syntheses Related to pH Regulation and Osmolarity Generation 31 IV. Conclusions on Energy Costs of pH Regulation During Nitrogen Assimilation and Growth 56 V. Conclusions on Energy Costs of Osmolarity Generation 60 VI. Water Costs of pH Regulation and Nitrogen Assimilation 61 VII. Water Costs of Osmolarity Generation 67 VIII. Nitrogen Costs of Osmolarity Generation 69 IX. Conclusions 70 Acknowledgements 72 References 73.}, } @article {pmid28561366, year = {1985}, author = {Ross, KG and Fletcher, DJC}, title = {GENETIC ORIGIN OF MALE DIPLOIDY IN THE FIRE ANT, SOLENOPSIS INVICTA (HYMENOPTERA: FORMICIDAE), AND ITS EVOLUTIONARY SIGNIFICANCE.}, journal = {Evolution; international journal of organic evolution}, volume = {39}, number = {4}, pages = {888-903}, doi = {10.1111/j.1558-5646.1985.tb00430.x}, pmid = {28561366}, issn = {1558-5646}, abstract = {Male diploidy was studied in natural populations of the fire ant, Solenopsis invicta, in order to find an explanation from population genetics for the apparently common occurrence of this phenomenon in some North American populations. The association of male diploidy with polygyne (more than one queen per colony) populations in this species led us to expect that the two phenomena are causally linked. We proposed three hypotheses, based on current knowledge of sex-determining mechanisms in the Hymenoptera, to explain the loss of genetic diversity associated with high rates of diploid male production in S. invicta: a) allelic diversity was reduced during colonization of North America by a small founder group; b) allelic diversity was reduced during subsequent subfounding of the several polygyne populations; and c) genetic structuring of polygyne populations due to local inbreeding caused reduced allelic diversity and/or increased homozygosity. An extensive survey revealed that diploid males are common in all four polygyne (P) populations studied, and that none occur in the monogyne (M) population in north-central Georgia. On the other hand, newly mated (i.e., colony-founding) queens from this same M population produced diploid males in the laboratory, and in the Georgia M and P populations, the frequencies of queens that produce diploid males were shown to be similar. We conclude that the frequent production of diploid males in S. invicta has resulted from a loss of allelic diversity during colonization of North America rather than from any special genetic attribute of P populations. We found no evidence for genetic structuring of the Georgia P population or for decreased allelic diversity relative to the Georgia M population. Thus, the exclusive occurrence of diploid males in P populations does not reflect a fundamental difference between P and M populations in the genetic determinants of male diploidy but is, rather, the result of differential mortality of diploid-male-producing colonies of the two forms. In view of these results, the common occurrence of male diploidy in the P form of S. invicta cannot be taken as evidence of a role for kin selection in the evolution of polygyny. (In this paper, "polygyny" is used to refer to a multiple-queen society.) Studies of the progeny of single queens with allozyme markers demonstrated that diploid male S. invicta are produced biparentally, as in other hymenopteran species. Diploid males were found to take part in the normal summer mating flights in the Georgia P population, although the significance of this behavior is unknown. Males sampled from two P populations exhibited bimodal size distributions, with the diploid males consistently larger than haploids. Assuming a single locus sex determinant, we estimate 15 alleles at this locus for both forms of the ant in North America.}, } @article {pmid28564214, year = {1985}, author = {Nunney, L}, title = {FEMALE-BIASED SEX RATIOS: INDIVIDUAL OR GROUP SELECTION?.}, journal = {Evolution; international journal of organic evolution}, volume = {39}, number = {2}, pages = {349-361}, doi = {10.1111/j.1558-5646.1985.tb05672.x}, pmid = {28564214}, issn = {1558-5646}, abstract = {The evolution of biased sex ratios in a randomly structured population stems from individual selection acting through local parental control (LPC) of the sex ratio and hence of the mating success of the sons and/or daughters. As a general rule, the sex ratio is biased away from the sex whose fitness is most affected by changes in the local sex ratio. This is the sex whose fitness is subject to the most effective parental control. The bias acts to increase the fitness of the rarer, controlled sex and to increase parental productivity. In the specific case of the evolution of the female-biased Hamiltonian ratios, LPC can affect the mating success of sons but has no effect on the success of daughters. It is argued here and elsewhere (Nunney, unpubl.) that group selection can only promote the spread of a genotype through the maintenance of a positive association of individuals of that genotype. The importance of positive association is well established in the special case of kin selection. Given such a definition, group selection plays no part in the evolution of the Hamiltonian sex ratios, although it is possible to conceive of circumstances under which group selection could favor an even more extreme sex ratio bias. In general, such circumstances involve kin selection. It is argued that the examination of differences in group productivity is not a useful way of looking at the process of natural selection, since (i) by dividing up almost any evolving population into random groups, some groups (those with the highest frequency of the fittest individuals) will be more productive than others; and (ii) in the specific case of the evolution of the Hamiltonian ratios, it is possible to develop models either with or without a group structure and get the same result. Hamilton (1967) originally suggested that a female-biased sex ratio arose in his model because of the advantage of reducing local mate competition (specifically, reducing competition between brothers for mates). This possibility was eliminated by developing a model in which competition between the brothers was prevented regardless of the sex ratio. It was found that the optimum sex-ratio strategy was unaffected. On the other hand, the idea of local parental control has, in each case examined, been able to account for the predicted optimum strategy.}, } @article {pmid28555832, year = {1984}, author = {Cheverud, JM}, title = {EVOLUTION BY KIN SELECTION: A QUANTITATIVE GENETIC MODEL ILLUSTRATED BY MATERNAL PERFORMANCE IN MICE.}, journal = {Evolution; international journal of organic evolution}, volume = {38}, number = {4}, pages = {766-777}, doi = {10.1111/j.1558-5646.1984.tb00349.x}, pmid = {28555832}, issn = {1558-5646}, } @article {pmid28555820, year = {1984}, author = {Uyenoyama, MK}, title = {INBREEDING AND THE EVOLUTION OF ALTRUISM UNDER KIN SELECTION: EFFECTS ON RELATEDNESS AND GROUP STRUCTURE.}, journal = {Evolution; international journal of organic evolution}, volume = {38}, number = {4}, pages = {778-795}, doi = {10.1111/j.1558-5646.1984.tb00350.x}, pmid = {28555820}, issn = {1558-5646}, } @article {pmid28555961, year = {1984}, author = {Silk, JB}, title = {MEASUREMENT OF THE RELATIVE IMPORTANCE OF INDIVIDUAL SELECTION AND KIN SELECTION AMONG FEMALES OF THE GENUS MACACA.}, journal = {Evolution; international journal of organic evolution}, volume = {38}, number = {3}, pages = {553-559}, doi = {10.1111/j.1558-5646.1984.tb00321.x}, pmid = {28555961}, issn = {1558-5646}, } @article {pmid24407459, year = {1983}, author = {Cohen, JA and Brower, LP}, title = {Cardenolide sequestration by the dogbane tiger moth (Cycnia tenera; Arctiidae).}, journal = {Journal of chemical ecology}, volume = {9}, number = {4}, pages = {521-532}, pmid = {24407459}, issn = {0098-0331}, abstract = {Cycnia tenera adults, reared as larvae onAsclepias humistrata, had 10 times higher cardenolide concentrations, and contained 15 times more total cardenolide, than did moths reared onA. tuberosa. Thin-layer chromatography confirmed that each individual cardenolide visualized in the adult moths reared on the former host plant corresponds to one present in the plant, thus demonstrating that the insects' cardenolides are indeed derived from the larval food. Adult weights were significantly greater when the larvae had been fed upon the higher cardenolide plant species,A. humistrata. Similar results for other milkweed-feeding insects have been interpreted by some authors as evidence against a metabolic cost of handling cardenolides. However, such interpretations confound cardenolide differences among milkweed species with other differences in plant primary and secondary chemistry that affect insect growth and development. While the cooccurrence inC. tenera of other noxious chemicals (e.g., alkaloids) is not precluded, cardenolides sequestered from larval host plants have probably contributed to the evolution of visual and auditory aposematism in this species. As the eggs are laid in large clutches and larvae are gregarious, such aposematism may have evolved via kin selection.}, } @article {pmid28568226, year = {1982}, author = {Westoby, M and Rice, B}, title = {EVOLUTION OF THE SEED PLANTS AND INCLUSIVE FITNESS OF PLANT TISSUES.}, journal = {Evolution; international journal of organic evolution}, volume = {36}, number = {4}, pages = {713-724}, doi = {10.1111/j.1558-5646.1982.tb05437.x}, pmid = {28568226}, issn = {1558-5646}, } @article {pmid31992006, year = {1982}, author = {Butynski, TM}, title = {Harem-male replacement and infanticide in the blue monkey (Cercopithecus mitus stuhlmanni) in the Kibale Forest, Uganda.}, journal = {American journal of primatology}, volume = {3}, number = {1-4}, pages = {1-22}, doi = {10.1002/ajp.1350030102}, pmid = {31992006}, issn = {1098-2345}, abstract = {This paper (1) describes the first observations of male replacement and infanticide in the blue monkey (Cercopithecus mitis stuhlmanni), (2) examines these observations in light of those hypotheses put forth to explain infanticide, and (3) presents two basic models through which additional hypotheses are developed. Five groups of blue monkeys were observed for 2,724 hr in the Kibale Forest, Uganda. The pattern of infanticide in the blue monkey was strikingly similar to that reported for other species of primates living in one-male bisexual groups. Data concerning infanticide in the blue monkey do not support the hypothesis that infanticide is a maladaptive behavioral pathology. The data indirectly support the hypothesis that infanticide is part of a flexible, adaptive reproductive strategy of new harem-males. According to Model I, two of the hypothese for explaining how infanticide may be adaptive to the perpetrator are not mutually exclusive. Model II suggests that the rate of infanticide is directly related to competition among males for females and indirectly related to tenure length of harem-males. Models I and II underscore the importance of understanding what variables determine tenure length in haremmales. It is cocluded that length of male tenure is most likely a critical determinant of inclusive fitness not only for males but also for females.}, } @article {pmid28581060, year = {1981}, author = {Wade, MJ and Breden, F}, title = {EFFECT OF INBREEDING ON THE EVOLUTION OF ALTRUISTIC BEHAVIOR BY KIN SELECTION.}, journal = {Evolution; international journal of organic evolution}, volume = {35}, number = {5}, pages = {844-858}, doi = {10.1111/j.1558-5646.1981.tb04948.x}, pmid = {28581060}, issn = {1558-5646}, } @article {pmid28563142, year = {1981}, author = {Aoki, K}, title = {ALGEBRA OF INCLUSIVE FITNESS.}, journal = {Evolution; international journal of organic evolution}, volume = {35}, number = {4}, pages = {659-663}, doi = {10.1111/j.1558-5646.1981.tb04927.x}, pmid = {28563142}, issn = {1558-5646}, } @article {pmid28309944, year = {1981}, author = {Bekoff, M}, title = {Vole population cycles: Kin-selection or familiarity?.}, journal = {Oecologia}, volume = {48}, number = {1}, pages = {131}, pmid = {28309944}, issn = {1432-1939}, } @article {pmid28581146, year = {1980}, author = {Wade, MJ}, title = {AN EXPERIMENTAL STUDY OF KIN SELECTION.}, journal = {Evolution; international journal of organic evolution}, volume = {34}, number = {5}, pages = {844-855}, doi = {10.1111/j.1558-5646.1980.tb04023.x}, pmid = {28581146}, issn = {1558-5646}, } @article {pmid28310928, year = {1980}, author = {Charnov, EL and Finerty, JP}, title = {Vole population cycles: A case for kin-selection?.}, journal = {Oecologia}, volume = {45}, number = {1}, pages = {1-2}, pmid = {28310928}, issn = {1432-1939}, abstract = {Kin-selection, as evidenced by aggression between individuals with a low coefficient of relation, may be a significant contributing factor in vole population cycles. Demographic and behavioral studies support this idea.}, } @article {pmid28568180, year = {1979}, author = {Craig, R}, title = {PARENTAL MANIPULATION, KIN SELECTION, AND THE EVOLUTION OF ALTRUISM.}, journal = {Evolution; international journal of organic evolution}, volume = {33}, number = {1Part2}, pages = {319-334}, doi = {10.1111/j.1558-5646.1979.tb04685.x}, pmid = {28568180}, issn = {1558-5646}, } @article {pmid21939438, year = {2012}, author = {Lefèvre, T and Chiang, A and Kelavkar, M and Li, H and Li, J and de Castillejo, CL and Oliver, L and Potini, Y and Hunter, MD and de Roode, JC}, title = {Behavioural resistance against a protozoan parasite in the monarch butterfly.}, journal = {The Journal of animal ecology}, volume = {81}, number = {1}, pages = {70-79}, doi = {10.1111/j.1365-2656.2011.01901.x}, pmid = {21939438}, issn = {1365-2656}, mesh = {Animals ; Apicomplexa/chemistry/*physiology ; Asclepias/*chemistry/parasitology ; Avoidance Learning ; Butterflies/*parasitology/*physiology ; Female ; Food Chain ; Food Preferences ; Larva/parasitology/physiology ; *Oviposition ; Species Specificity ; Spores, Protozoan/chemistry/physiology ; }, abstract = {1. As parasites can dramatically reduce the fitness of their hosts, there should be strong selection for hosts to evolve and maintain defence mechanisms against their parasites. One way in which hosts may protect themselves against parasitism is through altered behaviours, but such defences have been much less studied than other forms of parasite resistance. 2. We studied whether monarch butterflies (Danaus plexippus L.) use altered behaviours to protect themselves and their offspring against the protozoan parasite Ophryocystis elektroscirrha (McLaughlin & Myers (1970), Journal of Protozoology, 17, p. 300). In particular, we studied whether (i) monarch larvae can avoid contact with infectious parasite spores; (ii) infected larvae preferentially consume therapeutic food plants when given a choice or increase the intake of such plants in the absence of choice; and (iii) infected female butterflies preferentially lay their eggs on medicinal plants that make their offspring less sick. 3. We found that monarch larvae were unable to avoid infectious parasite spores. Larvae were also not able to preferentially feed on therapeutic food plants or increase the ingestion of such plants. However, infected female butterflies preferentially laid their eggs on food plants that reduce parasite growth in their offspring. 4. Our results suggest that animals may use altered behaviours as a protection against parasites and that such behaviours may be limited to a single stage in the host-parasite life cycle. Our results also suggest that animals may use altered behaviours to protect their offspring instead of themselves. Thus, our study indicates that an inclusive fitness approach should be adopted to study behavioural defences against parasites.}, } @article {pmid21929555, year = {2012}, author = {Banks, SC and Blyton, MD and Blair, D and McBurney, L and Lindenmayer, DB}, title = {Adaptive responses and disruptive effects: how major wildfire influences kinship-based social interactions in a forest marsupial.}, journal = {Molecular ecology}, volume = {21}, number = {3}, pages = {673-684}, doi = {10.1111/j.1365-294X.2011.05282.x}, pmid = {21929555}, issn = {1365-294X}, mesh = {Adaptation, Physiological ; Animal Migration ; Animals ; *Cooperative Behavior ; Demography ; *Disasters ; Ecosystem ; *Fires ; Marsupialia ; Sexual Behavior, Animal ; }, abstract = {Environmental disturbance is predicted to play a key role in the evolution of animal social behaviour. This is because disturbance affects key factors underlying social systems, such as demography, resource availability and genetic structure. However, because natural disturbances are unpredictable there is little information on their effects on social behaviour in wild populations. Here, we investigated how a major wildfire affected cooperation (sharing of hollow trees) by a hollow-dependent marsupial. We based two alternative social predictions on the impacts of fire on population density, genetic structure and resources. We predicted an adaptive social response from previous work showing that kin selection in den-sharing develops as competition for den resources increases. Thus, kin selection should occur in burnt areas because the fire caused loss of the majority of hollow-bearing trees, but no detectable mortality. Alternatively, fire may have a disruptive social effect, whereby postfire home range-shifts 'neutralize' fine-scale genetic structure, thereby removing opportunities for kin selection between neighbours. Both predictions occurred: the disruptive social effect in burnt habitat and the adaptive social response in adjacent unburnt habitat. The latter followed a massive demographic influx to unburnt 'refuge' habitat that increased competition for dens, leading to a density-related kin selection response. Our results show remarkable short-term plasticity of animal social behaviour and demonstrate how the social effects of disturbance extend into undisturbed habitat owing to landscape-scale demographic shifts. We predicted long-term changes in kinship-based cooperative behaviour resulting from the genetic and resource impacts of forecast changes to fire regimes in these forests.}, } @article {pmid21920980, year = {2011}, author = {Bourke, AF}, title = {The validity and value of inclusive fitness theory.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1723}, pages = {3313-3320}, pmid = {21920980}, issn = {1471-2954}, mesh = {*Altruism ; *Biological Evolution ; Genetic Fitness/*genetics ; *Models, Genetic ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Social evolution is a central topic in evolutionary biology, with the evolution of eusociality (societies with altruistic, non-reproductive helpers) representing a long-standing evolutionary conundrum. Recent critiques have questioned the validity of the leading theory for explaining social evolution and eusociality, namely inclusive fitness (kin selection) theory. I review recent and past literature to argue that these critiques do not succeed. Inclusive fitness theory has added fundamental insights to natural selection theory. These are the realization that selection on a gene for social behaviour depends on its effects on co-bearers, the explanation of social behaviours as unalike as altruism and selfishness using the same underlying parameters, and the explanation of within-group conflict in terms of non-coinciding inclusive fitness optima. A proposed alternative theory for eusocial evolution assumes mistakenly that workers' interests are subordinate to the queen's, contains no new elements and fails to make novel predictions. The haplodiploidy hypothesis has yet to be rigorously tested and positive relatedness within diploid eusocial societies supports inclusive fitness theory. The theory has made unique, falsifiable predictions that have been confirmed, and its evidence base is extensive and robust. Hence, inclusive fitness theory deserves to keep its position as the leading theory for social evolution.}, } @article {pmid21896748, year = {2011}, author = {Jarosch, A and Stolle, E and Crewe, RM and Moritz, RF}, title = {Alternative splicing of a single transcription factor drives selfish reproductive behavior in honeybee workers (Apis mellifera).}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108}, number = {37}, pages = {15282-15287}, pmid = {21896748}, issn = {1091-6490}, mesh = {Alternative Splicing/*genetics ; Animals ; Bees/*genetics ; Exons/genetics ; Female ; Gene Knockdown Techniques ; *Hierarchy, Social ; Insect Proteins/*genetics/metabolism ; Introns/genetics ; Models, Genetic ; Protein Isoforms/genetics/metabolism ; RNA Interference ; RNA, Messenger/genetics/metabolism ; RNA, Small Interfering/metabolism ; Reproduction/genetics ; Sexual Behavior, Animal/*physiology ; Transcription Factors/*genetics/metabolism ; }, abstract = {In eusocial insects the production of daughters is generally restricted to mated queens, and unmated workers are functionally sterile. The evolution of this worker sterility has been plausibly explained by kin selection theory [Hamilton W (1964) J Theor Biol 7:1-52], and many traits have evolved to prevent conflict over reproduction among the females in an insect colony. In honeybees (Apis mellifera), worker reproduction is regulated by the queen, brood pheromones, and worker policing. However, workers of the Cape honeybee, Apis mellifera capensis, can evade this control and establish themselves as social parasites by activating their ovaries, parthenogenetically producing diploid female offspring (thelytoky) and producing queen-like amounts of queen pheromones. All these traits have been shown to be strongly influenced by a single locus on chromosome 13 [Lattorff HMG, et al. (2007) Biol Lett 3:292-295]. We screened this region for candidate genes and found that alternative splicing of a gene homologous to the gemini transcription factor of Drosophila controls worker sterility. Knocking out the critical exon in a series of RNAi experiments resulted in rapid worker ovary activation-one of the traits characteristic of the social parasites. This genetic switch may be controlled by a short intronic splice enhancer motif of nine nucleotides attached to the alternative splice site. The lack of this motif in parasitic Cape honeybee clones suggests that the removal of nine nucleotides from the altruistic worker genome may be sufficient to turn a honeybee from an altruistic worker into a parasite.}, } @article {pmid21883578, year = {2012}, author = {Dobson, FS and Viblanc, VA and Arnaud, CM and Murie, JO}, title = {Kin selection in Columbian ground squirrels: direct and indirect fitness benefits.}, journal = {Molecular ecology}, volume = {21}, number = {3}, pages = {524-531}, doi = {10.1111/j.1365-294X.2011.05218.x}, pmid = {21883578}, issn = {1365-294X}, mesh = {Animals ; *Cooperative Behavior ; Female ; *Genetic Fitness ; Models, Theoretical ; Population Dynamics ; Sciuridae ; Selection, Genetic ; }, abstract = {Empirical and theoretical studies have supported kin selection by demonstrating nepotism or modelling its conditions and consequences. As an alternative, we previously found that female Columbian ground squirrels had greater direct fitness when more close kin were present. Extending those results, we used population matrix methods to calculate minimum estimates of individual fitness, estimated direct and indirect components of fitness, estimated inclusive fitness by adding the direct fitness (stripped of estimated influences of the social environment) and indirect fitness components together, and finally looked for inclusive fitness benefits of associations with close kin who seem to be 'genial neighbours'. We examined the estimated fitness of a sample of 35 females for which complete lifetimes were known for themselves, their mothers and their littermate sisters. Six of these females had no cosurviving adult close kin, and their direct fitness was significantly lower than 29 females with such kin (λ = 0.66 vs. λ = 1.23). The net fitness benefit of the presence of close kin was thus 0.57. The estimated indirect component of fitness through benefits to the direct fitness of close kin was 0.43. Thus, estimated inclusive fitness for females with cosurviving close kin (λ = 1.09) was significantly greater than that for females without surviving close kin (viz., λ = 0.66). The presence of closely related and philopatric female kin appeared to result in considerable fitness benefits for female ground squirrels, perhaps through the behavioural mechanisms of lowered aggression and other forms of behavioural cooperation.}, } @article {pmid21880091, year = {2012}, author = {Kappeler, PM and Fichtel, C}, title = {Female reproductive competition in Eulemur rufifrons: eviction and reproductive restraint in a plurally breeding Malagasy primate.}, journal = {Molecular ecology}, volume = {21}, number = {3}, pages = {685-698}, doi = {10.1111/j.1365-294X.2011.05255.x}, pmid = {21880091}, issn = {1365-294X}, mesh = {Animals ; *Competitive Behavior ; Female ; Genetic Fitness ; Lemur ; *Reproduction ; Selection, Genetic ; *Sexual Behavior, Animal ; Trees ; }, abstract = {In mammals with female philopatry, co-resident females inevitably compete with each other for resources or reproductive opportunities, thereby reducing the kin-selected benefits of altruism towards relatives. These counteracting forces of cooperation and competition among kin should be particularly pronounced in plurally breeding species with limited alternative breeding opportunities outside the natal group. However, little is still known about the costs of reproductive competition on females' fitness and the victims' potential counter-strategies. Here we summarize long-term behavioural, demographic and genetic data collected on a plurally breeding primate from Madagascar to illuminate mechanisms and effects of female reproductive competition, focusing on forcible eviction and potential reproductive restraint. The main results of our study indicate that females in groups of redfronted lemurs (Eulemur rufifrons) above a critical size suffer from competition from their close relatives: females in larger groups face an increased probability of not giving birth as well as a higher probability of being evicted, especially during the annual mating and birth seasons. Eviction is not predicted by the number of adult females, the number of close female relatives, female age or inter-annual variation in rainfall but only by total group size. Thus, eviction in this species is clearly linked with reproductive competition, it cannot be forestalled by reproductive restraint or having many relatives in the group, and it occurs in the absence of a clear dominance hierarchy. Our study therefore also underscores the notion that potential inclusive fitness benefits from living with relatives may have been generally over-rated and should not be taken for granted.}, } @article {pmid21849384, year = {2012}, author = {Maciejewski, W}, title = {Resistance and relatedness on an evolutionary graph.}, journal = {Journal of the Royal Society, Interface}, volume = {9}, number = {68}, pages = {511-517}, pmid = {21849384}, issn = {1742-5662}, mesh = {*Biological Evolution ; Computational Biology/*methods ; Electromagnetic Phenomena ; Genetic Fitness/*genetics ; Genetics, Population/*methods ; *Models, Theoretical ; }, abstract = {When investigating evolution in structured populations, it is often convenient to consider the population as an evolutionary graph-individuals as nodes, and whom they may act with as edges. There has, in recent years, been a surge of interest in evolutionary graphs, especially in the study of the evolution of social behaviours. An inclusive fitness framework is best suited for this type of study. A central requirement for an inclusive fitness analysis is an expression for the genetic similarity between individuals residing on the graph. This has been a major hindrance for work in this area as highly technical mathematics are often required. Here, I derive a result that links genetic relatedness between haploid individuals on an evolutionary graph to the resistance between vertices on a corresponding electrical network. An example that demonstrates the potential computational advantage of this result over contemporary approaches is provided. This result offers more, however, to the study of population genetics than strictly computationally efficient methods. By establishing a link between gene transfer and electric circuit theory, conceptualizations of the latter can enhance understanding of the former.}, } @article {pmid21839750, year = {2012}, author = {van Veelen, M and García, J and Sabelis, MW and Egas, M}, title = {Group selection and inclusive fitness are not equivalent; the Price equation vs. models and statistics.}, journal = {Journal of theoretical biology}, volume = {299}, number = {}, pages = {64-80}, doi = {10.1016/j.jtbi.2011.07.025}, pmid = {21839750}, issn = {1095-8541}, mesh = {Animals ; *Biological Evolution ; Cooperative Behavior ; Game Theory ; Genotype ; Group Processes ; *Models, Genetic ; Phenotype ; *Selection, Genetic ; }, abstract = {It is often suggested that any group selection model can be recast in terms of inclusive fitness. A standard reference to support that claim is "'Quantitative genetics, inclusive fitness, and group selection" by Queller (1992) in the American Naturalist 139 (3), 540-558. In that paper the Price equation is used for the derivation of this claim. Instead of a general derivation, we try out a simple model. For this simple example, we find that the result does not hold. The non-equivalence of group selection and kin selection is therefore not only an important finding in itself, but also a case where the use of the Price equation leads to a claim that is not correct. If results that are arrived at with the Price equation are not correct, they can typically be repaired by adding extra assumptions, or explicitly stating implicit ones. We give examples with relatively mild and with less mild extra assumptions. We also discuss why the Price equation is often referred to as dynamically insufficient, and we try to find out what Price's theorem could be.}, } @article {pmid21836014, year = {2011}, author = {Leadbeater, E and Carruthers, JM and Green, JP and Rosser, NS and Field, J}, title = {Nest inheritance is the missing source of direct fitness in a primitively eusocial insect.}, journal = {Science (New York, N.Y.)}, volume = {333}, number = {6044}, pages = {874-876}, doi = {10.1126/science.1205140}, pmid = {21836014}, issn = {1095-9203}, mesh = {Animals ; Behavior, Animal ; Biological Evolution ; *Cooperative Behavior ; Female ; *Genetic Fitness ; Male ; Microsatellite Repeats ; *Nesting Behavior ; Reproduction ; *Social Behavior ; Wasps/genetics/*physiology ; }, abstract = {Animals that cooperate with nonrelatives represent a challenge to inclusive fitness theory, unless cooperative behavior is shown to provide direct fitness benefits. Inheritance of breeding resources could provide such benefits, but this route to cooperation has been little investigated in the social insects. We show that nest inheritance can explain the presence of unrelated helpers in a classic social insect model, the primitively eusocial wasp Polistes dominulus. We found that subordinate helpers produced more direct offspring than lone breeders, some while still subordinate but most after inheriting the dominant position. Thus, while indirect fitness obtained through helping relatives has been the dominant paradigm for understanding eusociality in insects, direct fitness is vital to explain cooperation in P. dominulus.}, } @article {pmid21834140, year = {2011}, author = {Oh, KP}, title = {Inclusive fitness of 'kissing cousins': new evidence of a role for kin selection in the evolution of extra-pair mating in birds.}, journal = {Molecular ecology}, volume = {20}, number = {13}, pages = {2657-2659}, doi = {10.1111/j.1365-294x.2011.05118.x}, pmid = {21834140}, issn = {1365-294X}, mesh = {Animals ; Female ; Male ; Passeriformes/*physiology ; Sexual Behavior, Animal/*physiology ; }, abstract = {Social monogamy is nearly ubiquitous across avian taxa,but evidence from a proliferation of studies utilizing molecular paternity analysis suggests that sexual monogamy is the rare exception rather than the rule (Griffith et al. 2002). Efforts to explain the prevalence of extra-pair paternity (EPP) have largely focused on the potential fitness benefits for offspring genetic quality, as females are less likely to benefit directly from seeking extra-pair mates. In particular, there has been considerable interest in the degree to which EPP may represent an adaptive female strategy to avoid inbreeding (or outbreeding)depression when paired with a highly related (or unrelated)social mate (Kempenaers 2007). Others have argued that, because relatives share many genes identical by descent,females might increase their own inclusive fitness by providing additional breeding opportunities to genetically related males (Waser et al. 1986; Kokko & Ots 2006). Thus, in the absence of significant inbreeding depression, pursuing EPP with relatives should be favoured by kin selection, although there exist few unambiguous empirical examples of such preferences in the literature. In this issue of Molecular Ecology, Wang &Lu (2011) present an analysis of mating patterns with respect to genetic relatedness of social and extra-pair partners in the ground tit (Parus humilis), a facultative cooperative breeder in which socially monogamous pairs occasionally form cooperative groups with unpaired helper males (Fig. 1). Consistent with the predictions of the kin-selection hypothesis, females in both bi-parental and cooperative groups preferentially engaged in extra-pair matings with relatives, irrespective of relatedness to their social mates, and while suffering no apparent costs of inbreeding depression in their progeny. These finding shave several exciting implications for our understanding of avian mating system diversity and the evolution of cooperative breeding.}, } @article {pmid21792223, year = {2011}, author = {Giraud, T and Shykoff, JA}, title = {Bacterial cooperation controlled by mobile elements: kin selection versus infectivity.}, journal = {Heredity}, volume = {107}, number = {3}, pages = {277-8; author reply 279-81}, pmid = {21792223}, issn = {1365-2540}, mesh = {Bacteria/*genetics ; *Gene Transfer, Horizontal ; Interspersed Repetitive Sequences/*genetics ; Plasmids/*genetics ; }, } @article {pmid21763747, year = {2011}, author = {Garay, J and Móri, TF}, title = {Is envy one of the possible evolutionary roots of charity?.}, journal = {Bio Systems}, volume = {106}, number = {1}, pages = {28-35}, doi = {10.1016/j.biosystems.2011.06.004}, pmid = {21763747}, issn = {1872-8324}, mesh = {*Altruism ; *Charities ; *Competitive Behavior ; Humans ; }, abstract = {We introduce an evolutionary game in which envy and charity can be considered as a consequence of Darwinian competition, i.e. individuals aim at increasing their own proportion rather than their absolute contribution to the next generation, and other-regarding-preference is a "method" for that. If the damage is additive and its cost is low, an envious strategy defeats a neutral strategy (rational strategy maximizing its own income). If damage is multiplicative, then coexistence of neutral and envious strategists is possible. Envy is a conditional spiteful strategy, thus in envious groups there is less damage than in spiteful groups, so envy decreases the total cost of spiteful competition. Although envy can be selected out in a mixed population of envious, neutral and spiteful individuals when damage is additive, the envious-spiteful strategists (envious within its kin and spiteful outside its kin) outperform neutral and spiteful ones in a simple kin-selection scenario. Furthermore, Clytemnestra's strategy, namely donating to richer people to evokes envious attacks on them, can spread through an envious group. Moreover, the envious-donator strategy (giving to the poorest and damaging the richer individuals) can spread in the envious group. Charity is a "buy-off" behaviour, since the donator can decrease its own damage from envy, thus charity further decreases the total cost of spiteful competition.}, } @article {pmid21762433, year = {2011}, author = {Bonckaert, W and van Zweden, JS and d'Ettorre, P and Billen, J and Wenseleers, T}, title = {Colony stage and not facultative policing explains pattern of worker reproduction in the Saxon wasp.}, journal = {Molecular ecology}, volume = {20}, number = {16}, pages = {3455-3468}, doi = {10.1111/j.1365-294X.2011.05200.x}, pmid = {21762433}, issn = {1365-294X}, mesh = {Animals ; Denmark ; Female ; Genetic Variation ; Hydrocarbons/analysis ; Male ; Microsatellite Repeats ; Ovum ; Reproduction/physiology ; Sex Ratio ; Sexual Behavior, Animal/physiology ; Social Behavior ; Wasps/*physiology ; }, abstract = {Inclusive fitness theory predicts that in colonies of social Hymenoptera headed by a multiple-mated queen, workers should benefit from policing eggs laid by other workers. Foster & Ratnieks provided evidence that in the vespine wasp Dolichovespula saxonica, workers police other workers' eggs only in colonies headed by a multiple-mated queen, but not in those headed by a single-mated one. This conclusion, however, was based on a relatively small sample size, and the original study did not control for possible confounding variables such as the seasonal colony progression of the nests. Our aim, therefore, was to reinvestigate whether or not facultative worker policing occurs in D. saxonica. Remarkably, our data show that in the studied Danish population, there was no correlation between worker-worker relatedness and the percentage of worker-derived males. In addition, we show that variability in cuticular hydrocarbon profiles among the workers did not significantly correlate with relatedness and that workers therefore probably did not have sufficient information on queen mating frequency from the workers' cuticular hydrocarbon profiles. Hence, there was no evidence that workers facultatively policed other workers' eggs in response to queen mating frequency. Nevertheless, our data do show that the seasonal progression of the nest and the location in which the males were reared both explain the patterns of worker reproduction found. Overall, our results suggest that the earlier evidence for facultative worker policing in D. saxonica may have been caused by accidental correlations with certain confounding variables, or, alternatively, that there are large interpopulation differences in the expression of worker policing.}, } @article {pmid21757610, year = {2011}, author = {Heidel, AJ and Lawal, HM and Felder, M and Schilde, C and Helps, NR and Tunggal, B and Rivero, F and John, U and Schleicher, M and Eichinger, L and Platzer, M and Noegel, AA and Schaap, P and Glöckner, G}, title = {Phylogeny-wide analysis of social amoeba genomes highlights ancient origins for complex intercellular communication.}, journal = {Genome research}, volume = {21}, number = {11}, pages = {1882-1891}, pmid = {21757610}, issn = {1549-5469}, support = {BB/D013453/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/E016308/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; BB/E016308//BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Amino Acid Sequence/genetics ; Base Composition ; Biological Transport ; Cell Adhesion/genetics ; Cell Communication/genetics ; Cell Movement/genetics ; Centromere/genetics/metabolism ; Cytoskeleton/genetics ; Dictyostelium/*genetics/metabolism ; Evolution, Molecular ; *Genome, Protozoan ; Molecular Sequence Data ; Molecular Structure ; Nucleotides, Cyclic/metabolism ; Open Reading Frames ; *Phylogeny ; Protein Interaction Domains and Motifs ; Signal Transduction ; Synteny ; Telomere/genetics/metabolism ; Transcription, Genetic ; }, abstract = {Dictyostelium discoideum (DD), an extensively studied model organism for cell and developmental biology, belongs to the most derived group 4 of social amoebas, a clade of altruistic multicellular organisms. To understand genome evolution over long time periods and the genetic basis of social evolution, we sequenced the genomes of Dictyostelium fasciculatum (DF) and Polysphondylium pallidum (PP), which represent the early diverging groups 1 and 2, respectively. In contrast to DD, PP and DF have conventional telomere organization and strongly reduced numbers of transposable elements. The number of protein-coding genes is similar between species, but only half of them comprise an identifiable set of orthologous genes. In general, genes involved in primary metabolism, cytoskeletal functions and signal transduction are conserved, while genes involved in secondary metabolism, export, and signal perception underwent large differential gene family expansions. This most likely signifies involvement of the conserved set in core cell and developmental mechanisms, and of the diverged set in niche- and species-specific adaptations for defense and food, mate, and kin selection. Phylogenetic dating using a concatenated data set and extensive loss of synteny indicate that DF, PP, and DD split from their last common ancestor at least 0.6 billion years ago.}, } @article {pmid21750383, year = {2011}, author = {Gardner, A and Ross, L}, title = {The evolution of hermaphroditism by an infectious male-derived cell lineage: an inclusive-fitness analysis.}, journal = {The American naturalist}, volume = {178}, number = {2}, pages = {191-201}, doi = {10.1086/660823}, pmid = {21750383}, issn = {1537-5323}, mesh = {Animals ; *Biological Evolution ; Cell Lineage ; Female ; Genome, Insect ; Hemiptera/*genetics/physiology ; Hermaphroditic Organisms/*genetics ; Male ; Mating Preference, Animal ; Models, Genetic ; Ploidies ; Reproduction ; Selection, Genetic ; Sex Determination Processes ; }, abstract = {There has been much recent interest in the role for genetic conflicts to drive the evolution of genetic systems. Here we consider the evolution of hermaphroditism in the scale insect tribe Iceryini and the suggestion that this has been driven by conflict between a female and an infectious male tissue derived from her father. We perform an inclusive-fitness analysis to show that, owing to genetic relatedness between father and daughter, there is scope for collaboration as well as conflict over the establishment of the infectious tissue. We also consider the evolutionary interests of a maternally inherited bacterial symbiont that has been implicated in mediating the tissue's establishment. More generally, our analysis reveals that genetic conflicts can drive the evolution of hermaphroditism.}, } @article {pmid21729708, year = {2011}, author = {Gardner, A}, title = {Kin selection under blending inheritance.}, journal = {Journal of theoretical biology}, volume = {284}, number = {1}, pages = {125-129}, doi = {10.1016/j.jtbi.2011.06.028}, pmid = {21729708}, issn = {1095-8541}, mesh = {*Altruism ; Animals ; Biological Evolution ; Family ; Inheritance Patterns/genetics ; *Models, Genetic ; *Selection, Genetic ; Social Adjustment ; }, abstract = {Why did Darwin fail to develop his insights on kin selection into a proper theory of social adaptation? One suggestion has been that his inadequate understanding of heredity kept the problem out of focus. Here, I determine whether it is possible to develop a quantitative theory of kin selection upon the assumption of blending inheritance. I find that, whilst Hamilton's rule of kin selection can be readily derived under the assumption of blending inheritance, this mechanism complicates the computation of relatedness coefficients, and can even cause them to fluctuate over generations. Nevertheless, I show that the ultimate criterion for selection to favour any social trait - i.e. a time-average of Hamilton's rule - remains the same as under particulate inheritance. By eliminating the gene from the theory of kin selection, I clarify the role that it plays in the theory of social adaptation.}, } @article {pmid21716697, year = {2011}, author = {Fox, M and Johow, J and Knapp, LA}, title = {The selfish grandma gene: the roles of the x-chromosome and paternity uncertainty in the evolution of grandmothering behavior and longevity.}, journal = {International journal of evolutionary biology}, volume = {2011}, number = {}, pages = {165919}, pmid = {21716697}, issn = {2090-052X}, abstract = {When considering inclusive fitness, it is expected that individuals will provide more care towards those with whom they are more closely related. Thus, if a selfish X-linked genetic element influenced care giving, we would expect care giving to vary with X-relatedness. Recent studies have shown that X-chromosome inheritance patterns may influence selection of traits affecting behavior and life-history. Sexually antagonistic (SA) zygotic drive could encourage individuals to help those with whom they are more likely to share genetic material at the expense of other relatives. We reanalyze previously reported data in light of this new idea. We also evaluate the effects of paternity uncertainty on SA-zygotic drive. Our evidence suggests that human paternal discrepancy is relatively low. Using published models, we find the effects of paternal discrepancy do not override opportunity for selection based on X-relatedness. Based on these results, longevity and grandmothering behaviors, including favoritism, may be more heavily influenced by selection on the X-chromosome than by paternity uncertainty.}, } @article {pmid21696475, year = {2011}, author = {Thurin, N and Sery, N and Guimbretiere, R and Aron, S}, title = {Colony kin structure and breeding system in the ant genus Plagiolepis.}, journal = {Molecular ecology}, volume = {20}, number = {15}, pages = {3251-3260}, doi = {10.1111/j.1365-294X.2011.05161.x}, pmid = {21696475}, issn = {1365-294X}, mesh = {Alleles ; Animals ; Ants/*genetics ; Female ; *Genetics, Population ; Heterozygote ; Male ; Microsatellite Repeats ; Reproduction ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; }, abstract = {Relatedness is a central parameter in the evolution of sociality, because kin selection theory assumes that individuals involved in altruistic interactions are related. At least three reproductive characteristics are known to profoundly affect colony kin structure in social insects: the number of reproductive queens per colony, the relatedness among breeding queens and queen mating frequency. Both the occurrence of multiple queens (polygyny) and multiple mating (polyandry) decrease within-colony relatedness, while mating among sibs increases relatedness between the workers and the brood they rear. Using DNA microsatellites, we performed a detailed genetic analysis of the colony kin structure and breeding system in three ant species belonging to the genus Plagiolepis: P. schmitzii, P. taurica and P. maura. Our data show that queens of the three species mate multiply: queens of P. maura mate with 1-2 males, queens of P. taurica with 3-11 males and queens of P. schmitzii may have 1-14 different mates. Moreover, colonies are headed by multiple queens: P. taurica and P. maura are facultatively polygynous, while P. schmitzii is obligately polygynous. Despite polyandry and polygyny, relatedness within colonies remains high because all species are characterized by sib-mating, with a fixation index F(it) = 0.25 in P. taurica, 0.24 in P. schmitzii and 0.26 in P. maura, and because the male mates of a queen are on average closely related.}, } @article {pmid21690389, year = {2011}, author = {Queller, DC}, title = {Expanded social fitness and Hamilton's rule for kin, kith, and kind.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108 Suppl 2}, number = {Suppl 2}, pages = {10792-10799}, pmid = {21690389}, issn = {1091-6490}, mesh = {Animals ; *Biological Evolution ; Humans ; Models, Genetic ; Phenotype ; *Selection, Genetic ; Social Adjustment ; }, abstract = {Inclusive fitness theory has a combination of simplicity, generality, and accuracy that has made it an extremely successful way of thinking about and modeling effects on kin. However, there are types of social interactions that, although covered, are not illuminated. Here, I expand the inclusive fitness approach and the corresponding neighbor-modulated approach to specify two other kinds of social selection. Kind selection, which includes greenbeards and many nonadditive games, is where selection depends on an actor's trait having different effects on others depending on whether they share the trait. Kith selection includes social effects that do not require either kin or kind, such as mutualism and manipulation. It involves social effects of a trait that affect a partner, with feedback to the actor's fitness. I derive expanded versions of Hamilton's rule for kith and kind selection, generalizing Hamilton's insight that we can model social selection through a sum of fitness effects, each multiplied by an appropriate association coefficient. Kinship is, thus, only one of the important types of association, but all can be incorporated within an expanded inclusive fitness.}, } @article {pmid21690344, year = {2011}, author = {Nonacs, P}, title = {Kinship, greenbeards, and runaway social selection in the evolution of social insect cooperation.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {108 Suppl 2}, number = {Suppl 2}, pages = {10808-10815}, pmid = {21690344}, issn = {1091-6490}, mesh = {Alleles ; Animals ; Computer Simulation ; *Evolution, Molecular ; Genetic Variation ; Hymenoptera/*genetics ; Male ; Phenotype ; Reproduction/genetics ; Selection, Genetic/*genetics ; Social Behavior ; }, abstract = {Social Hymenoptera have played a leading role in development and testing of kin selection theory. Inclusive fitness models, following from Hamilton's rule, successfully predict major life history characteristics, such as biased sex investment ratios and conflict over parentage of male offspring. However, kin selection models poorly predict patterns of caste-biasing nepotism and reproductive skew within groups unless kin recognition constraints or group-level selection is also invoked. These successes and failures mirror the underlying kin recognition mechanisms. With reliable environmental cues, such as the sex of offspring or the origin of male eggs, predictions are supported. When only genetic recognition cues are potentially available, predictions are not supported. Mathematical simulations demonstrate that these differing mechanisms for determining kinship produce very different patterns of behavior. Decisions based on environmental cues for relatedness result in a robust mixture of cooperation and noncooperation depending on whether or not Hamilton's rule is met. In contrast, cooperation evolves under a wider range of conditions and to higher frequencies with genetic kin recognition as shared greenbeard traits. This "excess of niceness" matches the existing patterns in caste bias and reproductive skew; individuals often help others at an apparent cost to their inclusive fitness. The results further imply a potential for greenbeard-type kin recognition to create arbitrary runaway social selection for shared genetic traits. Suggestive examples in social evolution may be alloparental care and unicoloniality in ants. Differences in kin recognition mechanisms also can have consequences for maintenance of advantageous genetic diversity within populations.}, } @article {pmid21689191, year = {2011}, author = {Tiedemann, R and Paulus, KB and Havenstein, K and Thorstensen, S and Petersen, A and Lyngs, P and Milinkovitch, MC}, title = {Alien eggs in duck nests: brood parasitism or a help from Grandma?.}, journal = {Molecular ecology}, volume = {20}, number = {15}, pages = {3237-3250}, doi = {10.1111/j.1365-294X.2011.05158.x}, pmid = {21689191}, issn = {1365-294X}, mesh = {Aging ; Animals ; Clutch Size ; Ducks/*genetics ; Female ; Microsatellite Repeats ; *Nesting Behavior ; Oviparity ; *Ovum ; Sequence Analysis, DNA ; }, abstract = {Intraspecific brood parasitism (IBP) is a remarkable phenomenon by which parasitic females can increase their reproductive output by laying eggs in conspecific females' nests in addition to incubating eggs in their own nest. Kin selection could explain the tolerance, or even the selective advantage, of IBP, but different models of IBP based on game theory yield contradicting predictions. Our analyses of seven polymorphic autosomal microsatellites in two eider duck colonies indicate that relatedness between host and parasitizing females is significantly higher than the background relatedness within the colony. This result is unlikely to be a by-product of relatives nesting in close vicinity, as nest distance and genetic identity are not correlated. For eider females that had been ring-marked during the decades prior to our study, our analyses indicate that (i) the average age of parasitized females is higher than the age of nonparasitized females, (ii) the percentage of nests with alien eggs increases with the age of nesting females, (iii) the level of IBP increases with the host females' age, and (iv) the number of own eggs in the nest of parasitized females significantly decreases with age. IBP may allow those older females unable to produce as many eggs as they can incubate to gain indirect fitness without impairing their direct fitness: genetically related females specialize in their energy allocation, with young females producing more eggs than they can incubate and entrusting these to their older relatives. Intraspecific brood parasitism in ducks may constitute cooperation among generations of closely related females.}, } @article {pmid21682642, year = {2011}, author = {Strassmann, JE and Gilbert, OM and Queller, DC}, title = {Kin discrimination and cooperation in microbes.}, journal = {Annual review of microbiology}, volume = {65}, number = {}, pages = {349-367}, doi = {10.1146/annurev.micro.112408.134109}, pmid = {21682642}, issn = {1545-3251}, mesh = {Animals ; Bacteria/*genetics ; Bacterial Physiological Phenomena ; Cell Communication ; Eukaryota/genetics/physiology ; *Evolution, Molecular ; Fungi/*genetics/physiology ; Models, Genetic ; *Selection, Genetic ; }, abstract = {Recognition of relatives is important in microbes because they perform many behaviors that have costs to the actor while benefiting neighbors. Microbes cooperate for nourishment, movement, virulence, iron acquisition, protection, quorum sensing, and production of multicellular biofilms or fruiting bodies. Helping others is evolutionarily favored if it benefits others who share genes for helping, as specified by kin selection theory. If microbes generally find themselves in clonal patches, then no special means of discrimination is necessary. Much real discrimination is actually of kinds, not kin, as in poison-antidote systems, such as bacteriocins, in which cells benefit their own kind by poisoning others, and in adhesion systems, in which cells of the same kind bind together. These behaviors can elevate kinship generally and make cooperation easier to evolve and maintain.}, } @article {pmid21656333, year = {2012}, author = {Vasey, PL and VanderLaan, DP}, title = {Sexual orientation in men and avuncularity in Japan: implications for the kin selection hypothesis.}, journal = {Archives of sexual behavior}, volume = {41}, number = {1}, pages = {209-215}, doi = {10.1007/s10508-011-9763-z}, pmid = {21656333}, issn = {1573-2800}, mesh = {*Altruism ; *Biological Evolution ; *Homosexuality, Male ; Humans ; Japan ; Male ; Masculinity ; *Men ; Social Environment ; }, abstract = {The kin selection hypothesis for male androphilia posits that genes for male androphilia can be maintained in the population if the fitness costs of not reproducing directly are offset by enhancing inclusive fitness. In theory, androphilic males can increase their inclusive fitness by directing altruistic behavior toward kin, which, in turn, allows kin to increase their reproductive success. Previous research conducted in Western countries (U.S., UK) has failed to find any support for this hypothesis. In contrast, research conducted in Samoa has provided repeated support for it. In light of these cross-cultural differences, we hypothesized that the development of elevated avuncular (i.e., altruistic uncle-like) tendencies in androphilic males may be contingent on a relatively collectivistic cultural context. To test this hypothesis, we compared data on the avuncular tendencies and altruistic tendencies toward non-kin children of childless androphilic and gynephilic men in Japan, a culture that is known to be relatively collectivistic. The results of this study furnished no evidence that androphilic Japanese men exhibited elevated avuncular tendencies compared to their gynephilic counterparts. Moreover, there was no evidence that androphilic men's avuncular tendencies were more optimally designed (i.e., were more dissociated from their altruistic tendencies toward non-kin children) compared to gynephilic men. If an adaptively designed avuncular male androphilic phenotype exists and its development is contingent on a particular social environment, then the research presented here suggests that a collectivistic cultural context is insufficient, in and of itself, for the expression of such a phenotype.}, } @article {pmid21651814, year = {2011}, author = {Huth-Schwarz, A and León, A and Vandame, R and Moritz, RF and Kraus, FB}, title = {Workers dominate male production in the neotropical bumblebee Bombus wilmattae (Hymenoptera: Apidae).}, journal = {Frontiers in zoology}, volume = {8}, number = {1}, pages = {13}, pmid = {21651814}, issn = {1742-9994}, abstract = {BACKGROUND: Cooperation and conflict in social insects are closely linked to the genetic structure of the colony. Kin selection theory predicts conflict over the production of males between the workers and the queen and between the workers themselves, depending on intra-colonial relatedness but also on other factors like colony efficiency, sex ratios, cost of worker reproduction and worker dominance behaviour. In most bumblebee (Bombus) species the queen wins this conflict and often dominates male production. However, most studies in bumblebees have been conducted with only a few selected, mostly single mated species from temperate climate regions. Here we study the genetic colony composition of the facultative polyandrous neotropical bumblebee Bombus wilmattae, to assess the outcome of the queen-worker conflict over male production and to detect potential worker policing.

RESULTS: A total of 120 males from five colonies were genotyped with up to nine microsatellite markers to infer their parentage. Four of the five colonies were queen right at point of time of male sampling, while one had an uncertain queen status. The workers clearly dominated production of males with an average of 84.9% +/- 14.3% of males being worker sons. In the two doubly mated colonies 62.5% and 96.7% of the male offspring originated from workers and both patrilines participated in male production. Inferring the mother genotypes from the male offspring, between four to eight workers participated in the production of males.

CONCLUSIONS: In this study we show that the workers clearly win the queen-worker conflict over male production in B. wilmattae, which sets them apart from the temperate bumblebee species studied so far. Workers clearly dominated male production in the singly as well the doubly mated colonies, with up to eight workers producing male offspring in a single colony. Moreover no monopolization of reproduction by single workers occurred.}, } @article {pmid21644946, year = {2011}, author = {Powers, ST and Penn, AS and Watson, RA}, title = {The concurrent evolution of cooperation and the population structures that support it.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {6}, pages = {1527-1543}, doi = {10.1111/j.1558-5646.2011.01250.x}, pmid = {21644946}, issn = {1558-5646}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; *Genetic Variation ; Linkage Disequilibrium ; *Models, Biological ; Selection, Genetic ; Social Behavior ; }, abstract = {The evolution of cooperation often depends upon population structure, yet nearly all models of cooperation implicitly assume that this structure remains static. This is a simplifying assumption, because most organisms possess genetic traits that affect their population structure to some degree. These traits, such as a group size preference, affect the relatedness of interacting individuals and hence the opportunity for kin or group selection. We argue that models that do not explicitly consider their evolution cannot provide a satisfactory account of the origin of cooperation, because they cannot explain how the prerequisite population structures arise. Here, we consider the concurrent evolution of genetic traits that affect population structure, with those that affect social behavior. We show that not only does population structure drive social evolution, as in previous models, but that the opportunity for cooperation can in turn drive the creation of population structures that support it. This occurs through the generation of linkage disequilibrium between socio-behavioral and population-structuring traits, such that direct kin selection on social behavior creates indirect selection pressure on population structure. We illustrate our argument with a model of the concurrent evolution of group size preference and social behavior.}, } @article {pmid21620513, year = {2011}, author = {Marshall, JA}, title = {Group selection and kin selection: formally equivalent approaches.}, journal = {Trends in ecology & evolution}, volume = {26}, number = {7}, pages = {325-332}, doi = {10.1016/j.tree.2011.04.008}, pmid = {21620513}, issn = {1872-8383}, mesh = {Animals ; Biological Evolution ; Genetic Fitness ; *Models, Biological ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Inclusive fitness theory, summarised in Hamilton's rule, is a dominant explanation for the evolution of social behaviour. A parallel thread of evolutionary theory holds that selection between groups is also a candidate explanation for social evolution. The mathematical equivalence of these two approaches has long been known. Several recent papers, however, have objected that inclusive fitness theory is unable to deal with strong selection or with non-additive fitness effects, and concluded that the group selection framework is more general, or even that the two are not equivalent after all. Yet, these same problems have already been identified and resolved in the literature. Here, I survey these contemporary objections, and examine them in the light of current understanding of inclusive fitness theory.}, } @article {pmid21615287, year = {2011}, author = {Brown, WM}, title = {The parental antagonism theory of language evolution: preliminary evidence for the proposal.}, journal = {Human biology}, volume = {83}, number = {2}, pages = {213-245}, doi = {10.3378/027.083.0205}, pmid = {21615287}, issn = {1534-6617}, mesh = {Alleles ; *Animal Communication ; Animals ; *Evolution, Molecular ; Forkhead Transcription Factors/genetics ; Genetic Fitness/genetics ; Genomic Imprinting/*genetics/physiology ; Humans ; *Language ; Models, Genetic ; *Parents ; Phenotype ; Time Factors ; Ubiquitin-Protein Ligases/genetics ; }, abstract = {Language--as with most communication systems--likely evolved by means of natural selection. Accounts for the genetical selection of language can usually be divided into two scenarios, either of which used in isolation of the other appear insufficient to explain the phenomena: (1) there are group benefits from communicating, and (2) there are individual benefits from being a better communicator. In contrast, it is hypothesized that language phenotypes emerged during a coevolutionary struggle between parental genomes via genomic imprinting, which is differential gene expression depending on parental origin of the genetic element. It is hypothesized that relatedness asymmetries differentially selected for patrigene-caused language phenotypes to extract resources from mother (early in development) and matrigene-caused language phenotypes to influence degree of cooperativeness among asymmetric kin (later in development). This paper reports that imprinted genes have a high frequency of involvement in language phenotypes (~36%), considering their presumed rarity in the human genome (~2%). For example, two well-studied genes associated with language impairments (FOXP2 and UBE3A) exhibit parent-of- origin effects. Specifically, FOXP2 is putatively paternally expressed, whereas UBE3A is a maternally expressed imprinted gene. It is also hypothesized that the more unique and cooperative aspects of human language emerged to the benefit of matrilineal inclusive fitness. Consistent with this perspective, it is reported here that the X-chromosome has higher involvement in loci that have associations with language than would be expected by chance. It is also reported, for the first time, that human and chimpanzee maternally expressed overlapping imprinted genes exhibit greater evolutionary divergence (in terms of the degree of overlapping transcripts) than paternally expressed overlapping imprinted genes. Finally, an analysis of global language patterns reveals that paternally but not maternally silenced Alu elements are positively correlated with language diversity. Furthermore, there is a much higher than expected frequency of Alu elements inserted into the protein-coding machinery of imprinted and X-chromosomal language loci compared with nonimprinted language loci. Taken together these findings provide some support for parental antagonism theory. Unlike previous theories for language evolution, parental antagonism theory generates testable predictions at the proximate (e.g., neurocognitive areas important for social transmission and language capacities), ontogenetic (e.g., the function of language at different points of development), ultimate (e.g., inclusive fitness), and phylogenetic levels (e.g., the spread of maternally derived brain components in mammals, particularly in the hominin lineage), thus making human capacities for culture more tractable than previously thought.}, } @article {pmid21605218, year = {2011}, author = {Gardner, A and Welch, JJ}, title = {A formal theory of the selfish gene.}, journal = {Journal of evolutionary biology}, volume = {24}, number = {8}, pages = {1801-1813}, doi = {10.1111/j.1420-9101.2011.02310.x}, pmid = {21605218}, issn = {1420-9101}, mesh = {*Adaptation, Biological ; *Evolution, Molecular ; *Genetic Variation ; Genetics, Population ; *Models, Genetic ; Selection, Genetic ; }, abstract = {Adaptation is conventionally regarded as occurring at the level of the individual organism. In contrast, the theory of the selfish gene proposes that it is more correct to view adaptation as occurring at the level of the gene. This view has received much popular attention, yet has enjoyed only limited uptake in the primary research literature. Indeed, the idea of ascribing goals and strategies to genes has been highly controversial. Here, we develop a formal theory of the selfish gene, using optimization theory to capture the analogy of 'gene as fitness-maximizing agent' in mathematical terms. We provide formal justification for this view of adaptation by deriving mathematical correspondences that translate the optimization formalism into dynamical population genetics. We show that in the context of social interactions between genes, it is the gene's inclusive fitness that provides the appropriate maximand. Hence, genic selection can drive the evolution of altruistic genes. Finally, we use the formalism to assess the various criticisms that have been levelled at the theory of the selfish gene, dispelling some and strengthening others.}, } @article {pmid21585585, year = {2011}, author = {Wild, G}, title = {Direct fitness for dynamic kin selection.}, journal = {Journal of evolutionary biology}, volume = {24}, number = {7}, pages = {1598-1610}, doi = {10.1111/j.1420-9101.2011.02291.x}, pmid = {21585585}, issn = {1420-9101}, mesh = {Animals ; Behavior, Animal/*physiology ; *Biological Evolution ; Computer Simulation ; *Genetic Fitness ; *Models, Biological ; }, abstract = {The direct-fitness approach to modelling the evolution of social traits is an alternative to the classical inclusive-fitness-based approach. Despite both its utility and popularity, the direct-fitness approach has not yet been extended to include the analysis of dynamic traits, i.e. traits whose level of expression may vary over time. In this article, I apply the direct-fitness approach to cope with the evolution of a dynamic resource-allocation behaviour when this behaviour influences the fitness of relatives. I am able to implement the direct-fitness approach using components (reproductive value, fitness changes and measures of relatedness) found in standard, social-evolutionary models. I illustrate the modified direct-fitness model with an example studied by previous authors, and I show how the direct-fitness perspective can aid the validation of analytical results by means of a genetic algorithm.}, } @article {pmid21559320, year = {2011}, author = {Waibel, M and Floreano, D and Keller, L}, title = {A quantitative test of Hamilton's rule for the evolution of altruism.}, journal = {PLoS biology}, volume = {9}, number = {5}, pages = {e1000615}, pmid = {21559320}, issn = {1545-7885}, mesh = {*Altruism ; *Biological Evolution ; Computer Simulation ; Epistasis, Genetic ; Genetic Association Studies ; Models, Genetic ; Mutation ; Neural Networks, Computer ; Robotics ; *Selection, Genetic ; }, abstract = {The evolution of altruism is a fundamental and enduring puzzle in biology. In a seminal paper Hamilton showed that altruism can be selected for when rb - c > 0, where c is the fitness cost to the altruist, b is the fitness benefit to the beneficiary, and r is their genetic relatedness. While many studies have provided qualitative support for Hamilton's rule, quantitative tests have not yet been possible due to the difficulty of quantifying the costs and benefits of helping acts. Here we use a simulated system of foraging robots to experimentally manipulate the costs and benefits of helping and determine the conditions under which altruism evolves. By conducting experimental evolution over hundreds of generations of selection in populations with different c/b ratios, we show that Hamilton's rule always accurately predicts the minimum relatedness necessary for altruism to evolve. This high accuracy is remarkable given the presence of pleiotropic and epistatic effects as well as mutations with strong effects on behavior and fitness (effects not directly taken into account in Hamilton's original 1964 rule). In addition to providing the first quantitative test of Hamilton's rule in a system with a complex mapping between genotype and phenotype, these experiments demonstrate the wide applicability of kin selection theory.}, } @article {pmid21521199, year = {2011}, author = {Puurtinen, M}, title = {Mate choice for optimal (k)inbreeding.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {5}, pages = {1501-1505}, doi = {10.1111/j.1558-5646.2010.01217.x}, pmid = {21521199}, issn = {1558-5646}, mesh = {Animals ; Biological Evolution ; Female ; Genetic Fitness ; *Inbreeding ; Male ; *Mating Preference, Animal ; *Models, Biological ; }, abstract = {Mating between related individuals results in inbreeding depression, and this has been thought to select against incestuous matings. However, theory predicts that inbreeding can also be adaptive if it increases the representation of genes identical by descent in future generations. Here, I recapitulate the theory of inclusive fitness benefits of incest, and extend the existing theory by deriving the stable level of inbreeding in populations practicing mate choice for optimal inbreeding. The parsimonious assumptions of the model are that selection maximizes inclusive fitness, and that inbreeding depression is a linear function of homozygosity of offspring. The stable level of inbreeding that maximizes inclusive fitness, and is expected to evolve by natural selection, is shown to be less than previous theory suggests. For wide range of realistic inbreeding depression strengths, mating with intermediately related individuals maximizes inclusive fitness. The predicted preference for intermediately related individuals as reproductive partners is in qualitative agreement with empirical evidence from mate choice experiments and reproductive patterns in nature.}, } @article {pmid21510961, year = {2011}, author = {Uitdehaag, JC}, title = {Bet hedging based cooperation can limit kin selection and form a basis for mutualism.}, journal = {Journal of theoretical biology}, volume = {280}, number = {1}, pages = {76-87}, doi = {10.1016/j.jtbi.2011.04.002}, pmid = {21510961}, issn = {1095-8541}, mesh = {Animals ; *Evolution, Molecular ; *Models, Genetic ; *Mutation ; *Selection, Genetic ; }, abstract = {Mutualism is a mechanism of cooperation in which partners that differ help each other. As such, mutualism opposes mechanisms of kin selection and tag-based selection (for example the green beard mechanism), which are based on giving exclusive help to partners that are related or carry the same tag. In contrast to kin selection, which is a basis for parochialism and intergroup warfare, mutualism can therefore be regarded as a mechanism that drives peaceful coexistence between different groups and individuals. Here the competition between mutualism and kin (tag) selection is studied. In a model where kin selection and tag-based selection are dominant, mutualism is promoted by introducing environmental fluctuations. These fluctuations cause reduction in reproductive success by the mechanism of variance discount. The best strategy to counter variance discount is to share with agents who experience the most anticorrelated fluctuations, a strategy called bet hedging. In this way, bet hedging stimulates cooperation with the most unrelated partners, which is a basis for mutualism. Analytic results and simulations reveal that, if this effect is large enough, mutualistic strategies can dominate kin selective strategies. In addition, mutants of these mutualistic strategies that experience fluctuations that are more anticorrelated to their partner, can outcompete wild type, which can lead to the evolution of specialization. In this way, the evolutionary success of mutualistic strategies can be explained by bet hedging-based cooperation.}, } @article {pmid21490255, year = {2011}, author = {Martín-Gálvez, D and Pérez-Contreras, T and Soler, M and Soler, JJ}, title = {Benefits associated with escalated begging behaviour of black-billed magpie nestlings overcompensate the associated energetic costs.}, journal = {The Journal of experimental biology}, volume = {214}, number = {Pt 9}, pages = {1463-1472}, doi = {10.1242/jeb.050153}, pmid = {21490255}, issn = {1477-9145}, mesh = {Animals ; Cyproheptadine/pharmacology ; Energy Metabolism/drug effects/*physiology ; Feeding Behavior/drug effects/*physiology ; Nesting Behavior/drug effects/*physiology ; Passeriformes/*physiology ; Video Recording ; }, abstract = {Several experimental results support the existence of costs associated with exaggerated begging behaviour, which are assumed by some theoretical models of honest signalling in parent-offspring communication. However, to understand how honest begging behaviour is evolutionarily maintained in nature, the long-term cost-benefit output associated with exaggerated signals should also be estimated. As far as we know, the net cost-benefit balance of begging display has not previously been explored. Here, we used an appetite stimulant, cyproheptadine hydrochloride, to increase the feeling of hunger in some magpie nestlings. Supporting the use of cyproheptadine to manipulate hunger level and thereby begging behaviour, we found that experimental nestlings increased the frequency of begging and received more food than their control nestmates. Contrary to the expectation that physiological costs per se counteract the associated benefits of escalated begging signals, we found that near-fledging experimental magpies showed a better physical condition than control nestlings. These findings stress the interesting question of why magpie nestlings do not show to adults an escalated level of hunger if it implies an advantage. We discuss the responsibility of inclusive fitness costs and indirect genetic effects for the maintenance of honesty in parent-offspring communication.}, } @article {pmid21483861, year = {2011}, author = {Dejean, A and Corbara, B and Leroy, C and Delabie, JH and Rossi, V and Céréghino, R}, title = {Inherited biotic protection in a neotropical pioneer plant.}, journal = {PloS one}, volume = {6}, number = {3}, pages = {e18071}, pmid = {21483861}, issn = {1932-6203}, mesh = {Animals ; Ants/physiology ; Flowers/growth & development/physiology ; Gentianaceae/*growth & development/*physiology ; Pollination/physiology ; Reproduction/physiology ; Seed Dispersal/physiology ; }, abstract = {Chelonanthus alatus is a bat-pollinated, pioneer Gentianaceae that clusters in patches where still-standing, dried-out stems are interspersed among live individuals. Flowers bear circum-floral nectaries (CFNs) that are attractive to ants, and seed dispersal is both barochorous and anemochorous. Although, in this study, live individuals never sheltered ant colonies, dried-out hollow stems--that can remain standing for 2 years--did. Workers from species nesting in dried-out stems as well as from ground-nesting species exploited the CFNs of live C. alatus individuals in the same patches during the daytime, but were absent at night (when bat pollination occurs) on 60.5% of the plants. By visiting the CFNs, the ants indirectly protect the flowers--but not the plant foliage--from herbivorous insects. We show that this protection is provided mostly by species nesting in dried-out stems, predominantly Pseudomyrmex gracilis. That dried-out stems remain standing for years and are regularly replaced results in an opportunistic, but stable association where colonies are sheltered by one generation of dead C. alatus while the live individuals nearby, belonging to the next generation, provide them with nectar; in turn, the ants protect their flowers from herbivores. We suggest that the investment in wood by C. alatus individuals permitting still-standing, dried-out stems to shelter ant colonies constitutes an extended phenotype because foraging workers protect the flowers of live individuals in the same patch. Also, through this process these dried-out stems indirectly favor the reproduction (and so the fitness) of the next generation including both their own offspring and that of their siblings, all adding up to a potential case of inclusive fitness in plants.}, } @article {pmid21460570, year = {2011}, author = {Kingma, SA and Hall, ML and Peters, A}, title = {Multiple benefits drive helping behavior in a cooperatively breeding bird: an integrated analysis.}, journal = {The American naturalist}, volume = {177}, number = {4}, pages = {486-495}, doi = {10.1086/658989}, pmid = {21460570}, issn = {1537-5323}, mesh = {Animals ; Biological Evolution ; *Cooperative Behavior ; Female ; *Helping Behavior ; Male ; Nesting Behavior/*physiology ; Pair Bond ; Passeriformes/genetics/*physiology ; Reproduction ; }, abstract = {Several hypotheses exist to explain the seemingly altruistic helping behavior of cooperative breeders, although the general utility of these hypotheses remains unclear. While the potential importance of inclusive fitness benefits (kin selection) is traditionally widely appreciated, it is increasingly recognized that direct benefits may be more important than assumed. We use an integrative two-step framework to assess support for current hypotheses in purple-crowned fairy wrens, a species where subordinates vary in relatedness to breeders and helping increases productivity. After establishing that assumptions of pay-to-stay and social prestige hypotheses (predicting that helping functions as "paying rent" to stay on the territory or as a signal of individual quality, respectively) were not met and that parentage by subordinates is extremely rare, we tested whether subordinates adjusted nestling feeding rates following the predictions of the kin selection and group augmentation hypotheses. Benefits of kin selection result from investment in relatives, and group augmentation benefits accrue when subordinates invest more in their own future helpers, for example, when they have a better chance of inheriting the breeding position. We found that subordinates fed siblings more than unrelated nestlings, indicating that kin selection could facilitate cooperation. Moreover, the effect of relatedness on feeding effort varied depending on the probability of inheriting a breeding position, suggesting that active group augmentation can explain investment by unrelated subordinates. This statistical interaction would have gone undetected had we not considered both factors simultaneously, illustrating that a focus on single hypotheses could lead to underestimation of their importance in explaining cooperative breeding.}, } @article {pmid21460545, year = {2011}, author = {Walter, B and Brunner, E and Heinze, J}, title = {Policing effectiveness depends on relatedness and group size.}, journal = {The American naturalist}, volume = {177}, number = {3}, pages = {368-376}, doi = {10.1086/658396}, pmid = {21460545}, issn = {1537-5323}, mesh = {Aggression ; Animals ; Ants/*genetics ; *Biological Evolution ; Cooperative Behavior ; Fertility ; Genetic Fitness ; *Group Structure ; Reproduction ; *Social Behavior ; }, abstract = {Cohesion of social groups requires the suppression of individual selfishness. Indeed, worker egg laying in insect societies is usually suppressed or punished through aggression and egg removal. The effectiveness of such "policing" is expected to increase with decreasing relatedness, as inclusive fitness of group members is more strongly affected by selfish worker reproduction when group members are less closely related to each other. As inclusive fitness is also influenced by the costs and benefits of helping, the effectiveness of policing should decrease with increasing colony size, because the costs for the whole colony from selfish worker reproduction are proportionally reduced in large groups. Here, we show that policing effectiveness in colonies of the ant Temnothorax unifasciatus is low in large groups and high in small groups when relatedness is high. When we experimentally decreased the relatedness in groups, the policing effectiveness reached the same high level as in small, highly related groups, irrespective of group size. Therefore, our results indicate that policing effectiveness is simultaneously shaped by relatedness and group size, that is, an ecological factor. This may have major implications for testing policing across species of animals.}, } @article {pmid21460538, year = {2011}, author = {Van Dyken, JD and Linksvayer, TA and Wade, MJ}, title = {Kin selection-mutation balance: a model for the origin, maintenance, and consequences of social cheating.}, journal = {The American naturalist}, volume = {177}, number = {3}, pages = {288-300}, doi = {10.1086/658365}, pmid = {21460538}, issn = {1537-5323}, support = {R01GM084238/GM/NIGMS NIH HHS/United States ; }, mesh = {Altruism ; Animals ; *Biological Evolution ; Competitive Behavior ; *Conflict, Psychological ; Cooperative Behavior ; *Deception ; Gene Frequency ; Genetic Fitness ; Humans ; *Models, Genetic ; *Mutation ; Polymorphism, Genetic ; *Selection, Genetic ; }, abstract = {Social conflict, in the form of intraspecific selfish "cheating," has been observed in a number of natural systems. However, a formal, evolutionary genetic theory of social cheating that provides an explanatory, predictive framework for these observations is lacking. Here we derive the kin selection-mutation balance, which provides an evolutionary null hypothesis for the statics and dynamics of cheating. When social interactions have linear fitness effects and Hamilton's rule is satisfied, selection is never strong enough to eliminate recurrent cheater mutants from a population, but cheater lineages are transient and do not invade. Instead, cheating lineages are eliminated by kin selection but are constantly reintroduced by mutation, maintaining a stable equilibrium frequency of cheaters. The presence of cheaters at equilibrium creates a "cheater load" that selects for mechanisms of cheater control, such as policing. We find that increasing relatedness reduces the cheater load more efficiently than does policing the costs and benefits of cooperation. Our results provide new insight into the effects of genetic systems, mating systems, ecology, and patterns of sex-limited expression on social evolution. We offer an explanation for the widespread cheater/altruist polymorphism found in nature and suggest that the common fear of conflict-induced social collapse is unwarranted.}, } @article {pmid21457170, year = {2011}, author = {Rousset, F and Lion, S}, title = {Much ado about nothing: Nowak et al.'s charge against inclusive fitness theory.}, journal = {Journal of evolutionary biology}, volume = {24}, number = {6}, pages = {1386-1392}, doi = {10.1111/j.1420-9101.2011.02251.x}, pmid = {21457170}, issn = {1420-9101}, mesh = {Animals ; Behavior, Animal/*physiology ; Biological Evolution ; *Models, Biological ; *Publishing ; Selection, Genetic ; *Social Behavior ; }, abstract = {In a recent article, Nowak et al. claim that the mathematical basis of inclusive fitness theory does not stand to scrunity and to have found an alternative explanation for eusociality. We show that these claims are based on false premises, many of which have been exposed more than 25 years ago, such as misrepresentations of the basic components of inclusive fitness and fallacious distinctions between individual fitness and inclusive fitness. Moreover, some limitations ascribed to inclusive fitness are actually limitations of current evolutionary theory, for which Nowak et al. propose no new solution. Likewise, their assertedly 'common sense' empirical alternative to estimating inclusive fitness is not applicable in cases of interest. Finally, their eusociality model merely confirms the importance of all the components of inclusive fitness. We conclude by discussing how rhetorical devices and editorial practices can impede scientific endeavours.}, } @article {pmid21450738, year = {2011}, author = {McDonald, PG and Wright, J}, title = {Bell miner provisioning calls are more similar among relatives and are used by helpers at the nest to bias their effort towards kin.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1723}, pages = {3403-3411}, pmid = {21450738}, issn = {1471-2954}, support = {S19268/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 5/S19268/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; *Cooperative Behavior ; Gene Frequency ; Genetics, Population ; Genotype ; Likelihood Functions ; Male ; Microsatellite Repeats/genetics ; Models, Statistical ; Nesting Behavior/*physiology ; Passeriformes/*physiology ; Pedigree ; *Selection, Genetic ; Sound Spectrography ; Victoria ; Vocalization, Animal/*physiology ; }, abstract = {Kin selection predicts that helpers in cooperative systems should preferentially aid relatives to maximize fitness. In family-based groups, this can be accomplished simply by assisting all group members. In more complex societies, where large numbers of kin and non-kin regularly interact, more sophisticated kin-recognition mechanisms are needed. Bell miners (Manorina melanophrys) are just such a system where individuals regularly interact with both kin and non-kin within large colonies. Despite this complexity, individual helpers of both sexes facultatively work harder when provisioning the young of closer genetic relatedness. We investigated the mechanism by which such adaptive discrimination occurs by assessing genetic kinship influences on the structure of more than 1900 provisioning vocalizations of 185 miners. These 'mew' calls showed a significant, positive linear increase in call similarity with increasing genetic relatedness, most especially in comparisons between male helpers and the breeding male. Furthermore, individual helping effort was more heavily influenced by call similarity to breeding males than to genetic relatedness, as predicted if call similarity is indeed the rule-of-thumb used to discriminate kin in this system. Individual mew call structure appeared to be inflexible and innate, providing an effective mechanism by which helpers can assess their relatedness to any individual. This provides, to our knowledge, the first example of a mechanism for fine-scale kin discrimination in a complex avian society.}, } @article {pmid21438933, year = {2011}, author = {Wang, C and Lu, X}, title = {Female ground tits prefer relatives as extra-pair partners: driven by kin-selection?.}, journal = {Molecular ecology}, volume = {20}, number = {13}, pages = {2851-2863}, doi = {10.1111/j.1365-294X.2011.05070.x}, pmid = {21438933}, issn = {1365-294X}, mesh = {Animals ; Female ; Genotype ; Heterozygote ; Inbreeding ; Male ; Microsatellite Repeats/genetics ; Molecular Typing ; Passeriformes/genetics/*physiology ; Paternal Behavior ; Population Dynamics ; Reproduction ; Sexual Behavior, Animal/*physiology ; Tibet ; }, abstract = {Socially monogamous female birds routinely mate with males outside the pair bond. Three alternative hypotheses consider genetic benefits as the major driver behind the female strategy. The inbreeding avoidance hypothesis predicts that females paired with closely related males should seek copulations with distantly related extra-pair partners to avoid fitness loss from inbreeding depression; the outbreeding avoidance hypothesis predicts the opposite; the kin-selection hypothesis suggests that regardless of social mate relatedness, females should give related males extra-pair fertilization opportunities to gain inclusive fitness if the costs from inbreeding are minor. We test these hypotheses with a facultative cooperative breeder, the ground tit (Parus humilis). Social pairs of ground tits formed randomly with respect to genetic relatedness. In both bi-parental and cooperative groups, a female's engaging in extra-pair mating was independent of relatedness to her social mate; however, females preferred extra-pair sires to which they were more related than to their social mates. Moreover, females had higher relatedness with either their extra-group extra-pair sires in both bi-parental and cooperative groups, or within-group helper sires in cooperative groups, than expected by chance. When more than one potential extra-pair partner was available around a female's nest, she tended to select a relative. There was no indication of fitness reduction from extra-pair mating, which occurred at an intermediate level of inbreeding. These data support the kin-selection hypothesis, although there might be alternative nongenetic reasons associated with the extra-pair mating preference. Our finding offers a new explanation for why female birds pursue extra-pair mating. It also may broaden our understanding of the role of kin-selection in the evolution of cooperative society.}, } @article {pmid21430725, year = {2011}, author = {Herre, EA and Wcislo, WT}, title = {In defence of inclusive fitness theory.}, journal = {Nature}, volume = {471}, number = {7339}, pages = {E8-9; author reply E9-10}, pmid = {21430725}, issn = {1476-4687}, mesh = {Altruism ; Animals ; Biological Evolution ; Cooperative Behavior ; Female ; Game Theory ; *Genetic Fitness ; Genetics, Population ; Heredity ; Male ; *Models, Biological ; Models, Genetic ; Reproducibility of Results ; Selection, Genetic ; Sex Ratio ; }, abstract = {Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Arguably the defining characteristic of the scientific process is its capacity for self-criticism and correction. Nowak et al. challenge proposed connections between relatedness and the evolution of eusociality, suggest instead that defensible nests and "spring-loaded" traits are key, and present alternative modelling approaches. They then dismiss the utility of Hamilton's insight that relatedness has a profound evolutionary effect, formalized in his widely accepted inclusive fitness theory as Hamilton's rule ("Rise and fall of inclusive fitness theory"). However, we believe that Nowak et al. fail to make their case for logical, theoretical and empirical reasons.}, } @article {pmid21430724, year = {2011}, author = {Ferriere, R and Michod, RE}, title = {Inclusive fitness in evolution.}, journal = {Nature}, volume = {471}, number = {7339}, pages = {E6-8; author reply E9-10}, pmid = {21430724}, issn = {1476-4687}, mesh = {Alleles ; Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Female ; Game Theory ; *Genetic Fitness/genetics ; Genetics, Population ; Heredity/genetics ; Male ; *Models, Biological ; Phenotype ; Reproducibility of Results ; Selection, Genetic/genetics ; Sex Ratio ; }, abstract = {Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. For over fifty years, the evolution of social behaviour has been guided by the concept of inclusive fitness as a measure of evolutionary success. Nowak et al. argue that inclusive fitness should be abandoned. In so doing, however, they misrepresent the role that inclusive fitness has played in the theory of social evolution by which understanding social behaviour in a variety of disciplines has developed and flourished. By discarding inclusive fitness on the basis of its limitations, they create a conceptual tension which, we argue, is unnecessary, and potentially dangerous for evolutionary biology.}, } @article {pmid21430723, year = {2011}, author = {Strassmann, JE and Page, RE and Robinson, GE and Seeley, TD}, title = {Kin selection and eusociality.}, journal = {Nature}, volume = {471}, number = {7339}, pages = {E5-6; author reply E9-10}, pmid = {21430723}, issn = {1476-4687}, mesh = {*Altruism ; Animals ; Biological Evolution ; Cooperative Behavior ; Female ; Game Theory ; Genetic Fitness ; Genetics, Population ; Genomic Imprinting ; *Heredity ; Humans ; Male ; *Models, Biological ; Reproducibility of Results ; *Selection, Genetic ; Sex Ratio ; }, abstract = {Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Hamilton described a selective process in which individuals affect kin (kin selection), developed a novel modelling strategy for it (inclusive fitness), and derived a rule to describe it (Hamilton's rule). Nowak et al. assert that inclusive fitness is not the best modelling strategy, and also that its production has been "meagre". The former may be debated by theoreticians, but the latter is simply incorrect. There is abundant evidence to demonstrate that inclusive fitness, kin selection and Hamilton's rule have been extraordinarily productive for understanding the evolution of sociality.}, } @article {pmid21430722, year = {2011}, author = {Boomsma, JJ and Beekman, M and Cornwallis, CK and Griffin, AS and Holman, L and Hughes, WO and Keller, L and Oldroyd, BP and Ratnieks, FL}, title = {Only full-sibling families evolved eusociality.}, journal = {Nature}, volume = {471}, number = {7339}, pages = {E4-5; author reply E9-10}, pmid = {21430722}, issn = {1476-4687}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Female ; Game Theory ; Genetic Fitness ; Genetics, Population ; Male ; *Models, Biological ; Reproducibility of Results ; Reproduction/physiology ; Selection, Genetic ; Sex Ratio ; *Siblings ; }, abstract = {Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. The paper by Nowak et al. has the evolution of eusociality as its title, but it is mostly about something else. It argues against inclusive fitness theory and offers an alternative modelling approach that is claimed to be more fundamental and general, but which, we believe, has no practical biological meaning for the evolution of eusociality. Nowak et al. overlook the robust empirical observation that eusociality has only arisen in clades where mothers are associated with their full-sibling offspring; that is, in families where the average relatedness of offspring to siblings is as high as to their own offspring, independent of population structure or ploidy. We believe that this omission makes the paper largely irrelevant for understanding the evolution of eusociality.}, } @article {pmid21430721, year = {2011}, author = {Abbot, P and Abe, J and Alcock, J and Alizon, S and Alpedrinha, JA and Andersson, M and Andre, JB and van Baalen, M and Balloux, F and Balshine, S and Barton, N and Beukeboom, LW and Biernaskie, JM and Bilde, T and Borgia, G and Breed, M and Brown, S and Bshary, R and Buckling, A and Burley, NT and Burton-Chellew, MN and Cant, MA and Chapuisat, M and Charnov, EL and Clutton-Brock, T and Cockburn, A and Cole, BJ and Colegrave, N and Cosmides, L and Couzin, ID and Coyne, JA and Creel, S and Crespi, B and Curry, RL and Dall, SR and Day, T and Dickinson, JL and Dugatkin, LA and El Mouden, C and Emlen, ST and Evans, J and Ferriere, R and Field, J and Foitzik, S and Foster, K and Foster, WA and Fox, CW and Gadau, J and Gandon, S and Gardner, A and Gardner, MG and Getty, T and Goodisman, MA and Grafen, A and Grosberg, R and Grozinger, CM and Gouyon, PH and Gwynne, D and Harvey, PH and Hatchwell, BJ and Heinze, J and Helantera, H and Helms, KR and Hill, K and Jiricny, N and Johnstone, RA and Kacelnik, A and Kiers, ET and Kokko, H and Komdeur, J and Korb, J and Kronauer, D and Kümmerli, R and Lehmann, L and Linksvayer, TA and Lion, S and Lyon, B and Marshall, JA and McElreath, R and Michalakis, Y and Michod, RE and Mock, D and Monnin, T and Montgomerie, R and Moore, AJ and Mueller, UG and Noë, R and Okasha, S and Pamilo, P and Parker, GA and Pedersen, JS and Pen, I and Pfennig, D and Queller, DC and Rankin, DJ and Reece, SE and Reeve, HK and Reuter, M and Roberts, G and Robson, SK and Roze, D and Rousset, F and Rueppell, O and Sachs, JL and Santorelli, L and Schmid-Hempel, P and Schwarz, MP and Scott-Phillips, T and Shellmann-Sherman, J and Sherman, PW and Shuker, DM and Smith, J and Spagna, JC and Strassmann, B and Suarez, AV and Sundström, L and Taborsky, M and Taylor, P and Thompson, G and Tooby, J and Tsutsui, ND and Tsuji, K and Turillazzi, S and Ubeda, F and Vargo, EL and Voelkl, B and Wenseleers, T and West, SA and West-Eberhard, MJ and Westneat, DF and Wiernasz, DC and Wild, G and Wrangham, R and Young, AJ and Zeh, DW and Zeh, JA and Zink, A}, title = {Inclusive fitness theory and eusociality.}, journal = {Nature}, volume = {471}, number = {7339}, pages = {E1-4; author reply E9-10}, pmid = {21430721}, issn = {1476-4687}, support = {BB/H022716/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Female ; Game Theory ; *Genetic Fitness ; Genetics, Population ; Heredity ; Humans ; Male ; *Models, Biological ; Phenotype ; Reproducibility of Results ; *Selection, Genetic ; Sex Ratio ; }, abstract = {Arising from M. A. Nowak, C. E. Tarnita & E. O. Wilson 466, 1057-1062 (2010); Nowak et al. reply. Nowak et al. argue that inclusive fitness theory has been of little value in explaining the natural world, and that it has led to negligible progress in explaining the evolution of eusociality. However, we believe that their arguments are based upon a misunderstanding of evolutionary theory and a misrepresentation of the empirical literature. We will focus our comments on three general issues.}, } @article {pmid21393537, year = {2011}, author = {Hill, KR and Walker, RS and Bozicević, M and Eder, J and Headland, T and Hewlett, B and Hurtado, AM and Marlowe, F and Wiessner, P and Wood, B}, title = {Co-residence patterns in hunter-gatherer societies show unique human social structure.}, journal = {Science (New York, N.Y.)}, volume = {331}, number = {6022}, pages = {1286-1289}, doi = {10.1126/science.1199071}, pmid = {21393537}, issn = {1095-9203}, mesh = {Adult ; Cooperative Behavior ; Cross-Cultural Comparison ; *Cultural Evolution ; *Family ; Female ; Humans ; Male ; *Population Groups ; *Residence Characteristics ; *Social Behavior ; }, abstract = {Contemporary humans exhibit spectacular biological success derived from cumulative culture and cooperation. The origins of these traits may be related to our ancestral group structure. Because humans lived as foragers for 95% of our species' history, we analyzed co-residence patterns among 32 present-day foraging societies (total n = 5067 individuals, mean experienced band size = 28.2 adults). We found that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands. However, large social networks may help to explain why humans evolved capacities for social learning that resulted in cumulative culture.}, } @article {pmid21382866, year = {2011}, author = {Elsworth, C and Winward, C and Sackley, C and Meek, C and Freebody, J and Esser, P and Izadi, H and Soundy, A and Barker, K and Hilton-Jones, D and Lowe, CM and Paget, S and Tims, M and Parnell, R and Patel, S and Wade, D and Dawes, H}, title = {Supported community exercise in people with long-term neurological conditions: a phase II randomized controlled trial.}, journal = {Clinical rehabilitation}, volume = {25}, number = {7}, pages = {588-598}, doi = {10.1177/0269215510392076}, pmid = {21382866}, issn = {1477-0873}, support = {K-0806/PUK_/Parkinson's UK/United Kingdom ; }, mesh = {Adult ; Age Factors ; Aged ; Aged, 80 and over ; Chronic Disease ; Community Health Services/*organization & administration ; Disabled Persons/*rehabilitation ; *Exercise ; Exercise Tolerance/physiology ; Female ; Follow-Up Studies ; Humans ; Long-Term Care ; Male ; Middle Aged ; Nervous System Diseases/diagnosis/*rehabilitation ; Neuromuscular Diseases/diagnosis/rehabilitation ; Physical Fitness/*physiology ; Physical Therapy Modalities ; Risk Assessment ; Sex Factors ; Single-Blind Method ; Treatment Outcome ; United Kingdom ; }, abstract = {OBJECTIVE: Adults with long-term neurological conditions have low levels of participation in physical activities and report many barriers to participation in exercise. This study examines the feasibility and safety of supporting community exercise for people with long-term neurological conditions using a physical activity support system.

DESIGN: A phase II randomized controlled trial using computer-generated block randomization, allocation concealment and single blind outcome assessment.

SETTING: Oxfordshire and Birmingham community Inclusive Fitness Initiative gyms.

SUBJECTS: Patients with a long-term neurological condition.

INTERVENTIONS: The intervention group (n = 51) received a 12-week, supported exercise programme. The control group (n = 48) participants received standard care for 12 weeks and were then offered the intervention.

MAIN MEASURES: Physical activity, adherence to exercise, measures of mobility, health and well-being.

RESULTS: Forty-eight patients (n = 51) completed the intervention, achieving 14 gym attendances (range 0-39) over the 12 weeks. Overall activity did not increase as measured by the Physical Activity Scale for the Elderly (change score mean 14.31; 95% confidence interval (CI) −8.27 to 36.89) and there were no statistically significant changes in body function and health and well-being measures.

CONCLUSIONS: People with long-term neurological conditions can safely exercise in community gyms when supported and achieve similar attendance to standard exercise referral schemes, but may reduce other life activities in order to participate at a gym.}, } @article {pmid21380545, year = {2011}, author = {Buck, R}, title = {Communicative genes in the evolution of empathy and altruism.}, journal = {Behavior genetics}, volume = {41}, number = {6}, pages = {876-888}, doi = {10.1007/s10519-011-9456-3}, pmid = {21380545}, issn = {1573-3297}, mesh = {Adult ; *Altruism ; Brain/pathology ; Brain Injuries/physiopathology ; Child ; *Communication ; Cooperative Behavior ; Emotions ; Empathy/*genetics ; Evolution, Molecular ; *Genetics, Behavioral ; Humans ; Models, Genetic ; Phenotype ; Phylogeny ; Social Behavior ; }, abstract = {This paper discusses spontaneous communication and its implications for understanding empathy and altruism. The question of the possibility of "true" altruism-giving up one's genetic potential in favor of the genetic potential of another-is a fundamental issue common to the biological, behavioral, and social sciences. Darwin regarded "social instincts and sympathies" to be critical to the social order, but the possibility of biologically-based prosocial motives and emotions was questioned when selection was interpreted as operating at the level of the gene. In the selfish gene hypothesis, Dawkins argued that the unit of evolutionary selection must be an active, germ-line replicator: a unit whose activities determine whether copies of it are made across evolutionary timescales. He argued that the only active replicator existing across evolutionary timescales is the gene, so that the "selfish gene" is a replicator motivated only to make copies of itself. The communicative gene hypothesis notes that genes function by communicating, and the phenotype communication involves not only the individual sending and receiving abilities of the individual genes involved, but also the relationship between them relative to other genes. Therefore the selection of communication as phenotype involves the selection of individual genes and also their relationship. Relationships become replicators, and are selected across evolutionary timescales including social relationships (e.g., sex, nurturance, dominance-submission). An interesting implication of this view: apparent altruism has been interpreted by selfish gene theorists as due to kin selection and reciprocity, in which the survival of kin and comrade indirectly favor the genetic potential of the altruist. From the viewpoint of the communicative gene hypothesis, rather than underlying altruism, kin selection and reciprocity are ways of restricting altruism to kin and comrade: they are mechanisms not of altruism but of xenophobia.}, } @article {pmid21375755, year = {2011}, author = {Nonacs, P}, title = {Monogamy and high relatedness do not preferentially favor the evolution of cooperation.}, journal = {BMC evolutionary biology}, volume = {11}, number = {}, pages = {58}, pmid = {21375755}, issn = {1471-2148}, mesh = {Alleles ; Animals ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Female ; Genes, Dominant ; Genes, Recessive ; Genetic Fitness ; *Models, Biological ; *Sexual Behavior, Animal ; }, abstract = {BACKGROUND: Phylogenetic analyses strongly associate nonsocial ancestors of cooperatively-breeding or eusocial species with monogamy. Because monogamy creates high-relatedness family groups, kin selection has been concluded to drive the evolution of cooperative breeding (i.e., the monogamy hypothesis). Although kin selection is criticized as inappropriate for modeling and predicting the evolution of cooperation, there are no examples where specific inclusive fitness-based predictions are intrinsically wrong. The monogamy hypothesis may be the first case of such a flawed calculation.

RESULTS: A simulation model mutated helping alleles into non-cooperative populations where females mated either once or multiply. Although multiple mating produces sibling broods of lower relatedness, it also increases the likelihood that one offspring will adopt a helper role. Examining this tradeoff showed that under a wide range of conditions polygamy, rather than monogamy, allowed helping to spread more rapidly through populations. Further simulations with mating strategies as heritable traits confirmed that multiple-mating is selectively advantageous. Although cooperation evolves similarly regardless of whether dependent young are close or more distant kin, it does not evolve if they are unrelated.

CONCLUSIONS: The solitary ancestral species to cooperative breeders may have been predominantly monogamous, but it cannot be concluded that monogamy is a predisposing state for the evolution of helping behavior. Monogamy may simply be coincidental to other more important life history characteristics such as nest defense or sequential provisioning of offspring. The differing predictive outcome from a gene-based model also supports arguments that inclusive fitness formulations poorly model some evolutionary questions. Nevertheless, cooperation only evolves when benefits are provided for kin: helping alleles did not increase in frequency in the absence of potential gains in indirect fitness. The key question, therefore, is not whether kin selection occurs, but how best to elucidate the differing evolutionary advantages of genetic relatedness versus genetic diversity.}, } @article {pmid21371156, year = {2011}, author = {Gardner, A and West, SA and Wild, G}, title = {The genetical theory of kin selection.}, journal = {Journal of evolutionary biology}, volume = {24}, number = {5}, pages = {1020-1043}, doi = {10.1111/j.1420-9101.2011.02236.x}, pmid = {21371156}, issn = {1420-9101}, mesh = {Altruism ; Animals ; Family ; Least-Squares Analysis ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Natural selection operates both directly, via the impact of a trait upon the individual's own fitness, and indirectly, via the impact of the trait upon the fitness of the individual's genetically related social partners. These effects are often framed in terms of Hamilton's rule, rb - c > 0, which provides the central result of social-evolution theory. However, a number of studies have questioned the generality of Hamilton's rule, suggesting that it requires restrictive assumptions. Here, we use Fisher's genetical paradigm to demonstrate the generality of Hamilton's rule and to clarify links between different studies. We show that confusion has arisen owing to researchers misidentifying model parameters with the b and c terms in Hamilton's rule, and misidentifying measures of genotypic similarity or genealogical relationship with the coefficient of genetic relatedness, r. More generally, we emphasize the need to distinguish between general kin-selection theory that forms the foundations of social evolution, and streamlined kin-selection methodology that is used to solve specific problems.}, } @article {pmid21347812, year = {2011}, author = {Parvinen, K}, title = {Adaptive dynamics of altruistic cooperation in a metapopulation: evolutionary emergence of cooperators and defectors or evolutionary suicide?.}, journal = {Bulletin of mathematical biology}, volume = {73}, number = {11}, pages = {2605-2626}, doi = {10.1007/s11538-011-9638-4}, pmid = {21347812}, issn = {1522-9602}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Humans ; Mathematical Concepts ; Models, Psychological ; Population Dynamics ; }, abstract = {We investigate the evolution of public goods cooperation in a metapopulation model with small local populations, where altruistic cooperation can evolve due to assortment and kin selection, and the evolutionary emergence of cooperators and defectors via evolutionary branching is possible. Although evolutionary branching of cooperation has recently been demonstrated in the continuous snowdrift game and in another model of public goods cooperation, the required conditions on the cost and benefit functions are rather restrictive, e.g., altruistic cooperation cannot evolve in a defector population. We also observe selection for too low cooperation, such that the whole metapopulation goes extinct and evolutionary suicide occurs. We observed intuitive effects of various parameters on the numerical value of the monomorphic singular strategy. Their effect on the final coexisting cooperator-defector pair is more complex: changes expected to increase cooperation decrease the strategy value of the cooperator. However, at the same time the population size of the cooperator increases enough such that the average strategy does increase. We also extend the theory of structured metapopulation models by presenting a method to calculate the fitness gradient in a general class of metapopulation models, and try to make a connection with the kin selection approach.}, } @article {pmid21343946, year = {2011}, author = {Sibly, RM and Curnow, RN}, title = {Selfishness and altruism can coexist when help is subject to diminishing returns.}, journal = {Heredity}, volume = {107}, number = {2}, pages = {167-173}, pmid = {21343946}, issn = {1365-2540}, mesh = {Algorithms ; Alleles ; *Altruism ; Animals ; Genetics, Population ; Genotype ; Humans ; Models, Genetic ; Phenotype ; }, abstract = {Altruism and selfishness are 30-50% heritable in man in both Western and non-Western populations. This genetically based variation in altruism and selfishness requires explanation. In non-human animals, altruism is generally directed towards relatives, and satisfies the condition known as Hamilton's rule. This nepotistic altruism evolves under natural selection only if the ratio of the benefit of receiving help to the cost of giving it exceeds a value that depends on the relatedness of the individuals involved. Standard analyses assume that the benefit provided by each individual is the same but it is plausible in some cases that as more individuals contribute, help is subject to diminishing returns. We analyse this situation using a single-locus two-allele model of selection in a diploid population with the altruistic allele dominant to the selfish allele. The analysis requires calculation of the relationship between the fitnesses of the genotypes and the frequencies of the genes. The fitnesses vary not only with the genotype of the individual but also with the distribution of phenotypes amongst the sibs of the individual and this depends on the genotypes of his parents. These calculations are not possible by direct fitness or ESS methods but are possible using population genetics. Our analysis shows that diminishing returns change the operation of natural selection and the outcome can now be a stable equilibrium between altruistic and selfish alleles rather than the elimination of one allele or the other. We thus provide a plausible genetic model of kin selection that leads to the stable coexistence in the same population of both altruistic and selfish individuals. This may explain reported genetic variation in altruism in man.}, } @article {pmid21331239, year = {2010}, author = {Schino, G and Aureli, F}, title = {A few misunderstandings about reciprocal altruism.}, journal = {Communicative & integrative biology}, volume = {3}, number = {6}, pages = {561-563}, pmid = {21331239}, issn = {1942-0889}, abstract = {Current discussion about reciprocal altruism is plagued by a few points of continuing disagreement/misunderstanding. In order to facilitate progress in understanding the role of reciprocity in animal societies, in this paper we try to highlight these points of disagreement/misunderstanding. Our contribution can be summarized by the following statements: (1) A temporal contingency between action and reciprocation is not the sole valid evidence for reciprocal altruism; (2) Reciprocity is not (always) cognitively demanding; (3) Kin biases in altruism are not necessarily and entirely due to kin selection; (4) Mutualism can also involve reciprocal partner choice; (5) Biological market theory is an extension of reciprocal altruism theory.}, } @article {pmid21328594, year = {2011}, author = {Rosenbaum, S and Silk, JB and Stoinski, TS}, title = {Male-immature relationships in multi-male groups of mountain gorillas (Gorilla beringei beringei).}, journal = {American journal of primatology}, volume = {73}, number = {4}, pages = {356-365}, doi = {10.1002/ajp.20905}, pmid = {21328594}, issn = {1098-2345}, mesh = {Animals ; Behavior, Animal ; Female ; Gorilla gorilla/*physiology ; Male ; *Paternal Behavior ; Reproduction ; *Social Behavior ; }, abstract = {We examined the pattern and possible functions of social interactions between adult males and immatures in three free-ranging, multi-male groups of mountain gorillas (Gorilla beringei beringei). Previous studies conducted during the 1970s when groups contained one to three adult males concluded that male-immature relationships were likely to be a form of low-cost paternal investment [Stewart, Mountain gorillas: three decades of research at Karisoke. Cambridge, UK: Cambridge University Press, 2001]. We evaluated whether this hypothesis still held in groups containing six to nine adult males, or if male-immature relationships might serve other functions (e.g. mating effort, kin selection, or alliance building). Overall, we found that immatures spent the most time near, and interacted most with, the alpha silverback. These behaviors peaked during the period when infants were still quite vulnerable but increasing their independence from their mothers. Such findings suggest that parenting effort remains the primary function of male-immature relationships; however, there is some evidence for the mating effort hypothesis as well.}, } @article {pmid21320902, year = {2011}, author = {Ihara, Y}, title = {Evolution of culture-dependent discriminate sociality: a gene-culture coevolutionary model.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {366}, number = {1566}, pages = {889-900}, pmid = {21320902}, issn = {1471-2970}, mesh = {*Biological Evolution ; *Cultural Evolution ; Humans ; *Models, Theoretical ; *Social Behavior ; }, abstract = {Animals behave cooperatively towards certain conspecifics while being indifferent or even hostile to others. The distinction is made primarily according to kinship as predicted by the kin selection theory. With regards to humans, however, this is not always the case; in particular, humans sometimes exhibit a discriminate sociality on the basis of culturally transmitted traits, such as personal ornaments, languages, rituals, etc. This paper explores the possibility that the human faculty of cultural transmission and resultant cultural variation among individuals may have facilitated the evolution of discriminate sociality in humans. To this end, a gene-culture coevolutionary model is developed focusing on competition over control of resource as a context in which discriminate sociality may have evolved. Specifically, two types of culture-dependent discriminate sociality are considered: ingroup favouritism, with ingroup and outgroup being distinguished by the presence or absence of a cultural trait; and prestige hierarchies, with the prestige being conferred on the bearer of a cultural trait. The model specifies the conditions under which emergence and evolutionary stability of the two types of discriminate sociality are promoted by the presence of cultural variation among individuals.}, } @article {pmid21295593, year = {2011}, author = {van Veelen, M}, title = {The replicator dynamics with n players and population structure.}, journal = {Journal of theoretical biology}, volume = {276}, number = {1}, pages = {78-85}, doi = {10.1016/j.jtbi.2011.01.044}, pmid = {21295593}, issn = {1095-8541}, mesh = {*Game Theory ; Humans ; *Models, Biological ; *Population Dynamics ; }, abstract = {The well-known replicator dynamics is usually applied to 2-player games and random matching. Here we allow for games with n players, and for population structures other than random matching. This more general application leads to a version of the replicator dynamics of which the standard 2-player, well-mixed version is a special case, and which allows us to explore the dynamic implications of population structure. The replicator dynamics also allows for a reformulation of the central theorem in Van Veelen (2009), which claims that inclusive fitness gives the correct prediction for games with generalized equal gains from switching (or, in other words, when fitness effects are additive). If we furthermore also assume that relatedness is constant during selection - which is a reasonable assumption in a setting with kin recognition - then inclusive fitness even becomes a parameter that determines the speed as well as the direction of selection. For games with unequal gains from switching, inclusive fitness can give the wrong prediction. With equal gains however, not only the sign, but also even the value of inclusive fitness becomes meaningful.}, } @article {pmid21288953, year = {2011}, author = {Banks, SC and Lindenmayer, DB and McBurney, L and Blair, D and Knight, EJ and Blyton, MD}, title = {Kin selection in den sharing develops under limited availability of tree hollows for a forest marsupial.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1719}, pages = {2768-2776}, pmid = {21288953}, issn = {1471-2954}, mesh = {Adaptation, Physiological ; Animals ; Australia ; Behavior, Animal ; *Cooperative Behavior ; *Eucalyptus ; Female ; Inbreeding ; Male ; Marsupialia/*physiology ; Siblings ; Social Behavior ; *Territoriality ; *Trees ; }, abstract = {Animal social behaviour is not static with regard to environmental change. Flexibility in cooperative resource use may be an important response to resource decline, mediating the impacts of resource availability on fitness and demography. In forest ecosystems, hollow trees are key den resources for many species, but are declining worldwide owing to forestry. Altered patterns of den sharing may mediate the effects of the decline of this resource. We studied den-sharing interactions among hollow-dependent Australian mountain brushtail possums to investigate how spatial variation in hollow tree availability affects resource sharing and kin selection. Under reduced den availability, individuals used fewer dens and shared them less often. This suggests increased territoriality in the presence of resource competition. Further, there was a switch from kin avoidance to kin preference with decreasing hollow tree availability. This was driven primarily by a change in den sharing among siblings. The inclusive fitness benefits of den sharing with kin are likely to increase under resource-limiting conditions, but are potentially outweighed by the benefits of associating with non-relatives (avoidance of inbreeding or pathogen transmission) where dens are abundant. We discuss how predictions from social evolutionary theory can contribute to understanding animal responses to landscape change.}, } @article {pmid21178478, year = {2010}, author = {Czárán, T and F, HR}, title = {Janus-headed communication promotes bacterial cooperation and cheating: is quorum sensing useful against infections?.}, journal = {Virulence}, volume = {1}, number = {5}, pages = {402-403}, doi = {10.4161/viru.1.5.12549}, pmid = {21178478}, issn = {2150-5608}, mesh = {Bacteria/*pathogenicity ; *Bacterial Physiological Phenomena ; *Quorum Sensing ; Virulence ; Virulence Factors/genetics/*metabolism ; }, abstract = {In a detailed spatially explicit simulation study (Czárán & Hoekstra, 2009) we have shown that quorum sensing (QS)--the ability of bacteria to detect the local density of their clonemates in their immediate neighbourhood--might have evolved in synergism with cooperative behavior, i.e., the production of "public goods" like virulence factors for the common benefit of the cooperators, in spite of the fact that both cooperation and QS communication can be cheated (exploited) by mutant strains. In particular, we found that 1) cooperation requires an effective kin selection mechanism to operate, which is automatically supplied by the limited mobility of bacteria; 2) QS communication extends the scope for cooperation considerably, and cooperation maintains the selective advantage of QS communication, even if 3) different types of cheaters are always present and coexistent with "honest" phenotypes in a quasi-equilibrium. These predictions are validated by experimental results and field data by now, and medical applications of the results have been suggested.}, } @article {pmid21123273, year = {2011}, author = {Levitis, DA}, title = {Before senescence: the evolutionary demography of ontogenesis.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1707}, pages = {801-809}, pmid = {21123273}, issn = {1471-2954}, support = {T32 AG000246/AG/NIA NIH HHS/United States ; T32-AG000246/AG/NIA NIH HHS/United States ; }, mesh = {Adaptation, Biological ; Age Factors ; *Aging ; Animals ; *Biological Evolution ; Humans ; *Life Tables ; *Mortality ; Phylogeny ; Risk Factors ; Selection, Genetic ; }, abstract = {The age-specific mortality curve for many species, including humans, is U-shaped: mortality declines with age in the developing cohort (ontogenescence) before increasing with age (senescence). The field of evolutionary demography has long focused on understanding the evolution of senescence while largely failing to address the evolution of ontogenescence. The current review is the first to gather the few available hypotheses addressing the evolution of ontogenescence, examine the basis and assumptions of each and ask what the phylogenetic extent of ontogenescence may be. Ontogenescence is among the most widespread of life-history traits, occurring in every population for which I have found sufficiently detailed data, in major groups throughout the eukaryotes, across many causes of death and many life-history types. Hypotheses seeking to explain ontogenescence include those based on kin selection, the acquisition of robustness, heterogeneous frailties and life-history optimization. I propose a further hypothesis, arguing that mortality drops with age because most transitions that could trigger the risks caused by genetic and developmental malfunctions are concentrated in early life. Of these hypotheses, only those that frame ontogenescence as an evolutionary by-product rather than an adaptation can explain the tremendous diversity of organisms and environments in which it occurs.}, } @article {pmid21117963, year = {2011}, author = {Wolf, JB and Traulsen, A and James, R}, title = {Exploring the Link between Genetic Relatedness r and Social Contact Structure k in Animal Social Networks.}, journal = {The American naturalist}, volume = {177}, number = {1}, pages = {135-142}, doi = {10.1086/657442}, pmid = {21117963}, issn = {1537-5323}, mesh = {Animals ; Biological Evolution ; Community Networks ; Game Theory ; Genetic Fitness ; *Hierarchy, Social ; Models, Biological ; Sea Lions/*genetics/psychology ; *Selection, Genetic ; }, abstract = {Our understanding of how cooperation can arise in a population of selfish individuals has been greatly advanced by theory. More than one approach has been used to explore the effect of population structure. Inclusive fitness theory uses genetic relatedness r to express the role of population structure. Evolutionary graph theory models the evolution of cooperation on network structures and focuses on the number of interacting partners k as a quantity of interest. Here we use empirical data from a hierarchically structured animal contact network to examine the interplay between independent, measurable proxies for these key parameters. We find strong inverse correlations between estimates of r and k over three levels of social organization, suggesting that genetic relatedness and social contact structure capture similar structural information in a real population.}, } @article {pmid21070841, year = {2011}, author = {Shuai, L and Song, YL}, title = {Foraging behavior of the midday gerbil (Meriones meridianus): combined effects of distance and microhabitat.}, journal = {Behavioural processes}, volume = {86}, number = {1}, pages = {143-148}, doi = {10.1016/j.beproc.2010.11.001}, pmid = {21070841}, issn = {1872-8308}, mesh = {Animals ; Distance Perception ; *Ecosystem ; Energy Intake/physiology ; Environment ; Feeding Behavior/*physiology ; Gerbillinae ; Predatory Behavior ; Risk-Taking ; Seeds ; }, abstract = {We used the giving-up density (GUD) method and direct observation to study the combined effects of travel distance and microhabitat on foraging behavior of the midday gerbil (Meriones meridianus), which often acts as a central place forager. We provided animals with artificial seed trays in which dry and unhusked pumpkin seeds were mixed with fine sand. Gerbils practiced an eat-and-carry strategy in patches of bush microhabitat that were far from central places (BF patches), and tended to carry all seeds back in the other three treatments. Resource protection, predation risk avoidance and the balance between future and present value of food items may contribute to the eat-and-carry strategy. When distance was held constant, GUDs in open patches were higher than in bush patches, which was consistent with most studies. When microhabitat was held constant, GUDs in nearer patches were normally lower than in farther patches. In most cases, gerbils preferred to carry more seeds back rather than consume them immediately. We concluded that this tendency was due to the gerbils balancing the factors of future value and present value, and individual fitness and inclusive fitness.}, } @article {pmid21062277, year = {2011}, author = {Archetti, M and Scheuring, I}, title = {Coexistence of cooperation and defection in public goods games.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {4}, pages = {1140-1148}, doi = {10.1111/j.1558-5646.2010.01185.x}, pmid = {21062277}, issn = {1558-5646}, mesh = {*Cooperative Behavior ; *Game Theory ; Humans ; *Models, Psychological ; }, abstract = {The production of public goods by the contribution of individual volunteers is a social dilemma because an individual that does not volunteer can benefit from the public good produced by the contributions of others. Therefore it is generally believed that public goods can be produced only in the presence of repeated interactions (which allow reciprocation, reputation effects and punishment) or relatedness (kin selection). Cooperation, however, often occurs in the absence of iterations and relatedness. We show that when the production of a public good is a Volunteer's Dilemma, in which a fixed number of cooperators is necessary to produce the public good, cooperators and defectors persist in a mixed equilibrium, without iterations and without relatedness. This mixed equilibrium is absent in the N-person Prisoner's Dilemma, in which the public good is a linear function of the individual contributions. We also show that the Prisoner's Dilemma and the Volunteer's Dilemma are the two opposite extremes of a general public goods game, and that all intermediate cases can have a mixed equilibrium like the Volunteer's Dilemma. The coexistence of cooperators and defectors, therefore, is a typical outcome of most social dilemmas, which requires neither relatedness nor iterations.}, } @article {pmid21054623, year = {2011}, author = {Rankin, DJ}, title = {Kin selection and the evolution of sexual conflict.}, journal = {Journal of evolutionary biology}, volume = {24}, number = {1}, pages = {71-81}, doi = {10.1111/j.1420-9101.2010.02143.x}, pmid = {21054623}, issn = {1420-9101}, mesh = {Animal Migration ; Animals ; *Conflict, Psychological ; Female ; Inbreeding ; Male ; *Models, Biological ; Sex Factors ; *Sexual Behavior, Animal ; }, abstract = {Males and females do not always share the same evolutionary interests. This is particularly true in the case of multiple mating, where male-male competition can often lead to adaptations that are harmful to the female, and females can evolve counter adaptations to reduce the benefits males gain from such traits. Although social evolution has made substantial progress from kin selection theory, most studies of sexual conflict have ignored the effects of genetic relatedness. Here, I use a model of male harm and female resistance to investigate how kin selection affects the evolution of sexual conflict. Building on models of social evolution, I show that relatedness inhibits sexual conflict, in terms of male harm, whereas it has no effect on the evolution female resistance. This study examines a previously neglected mechanism that can potentially help to resolve sexual conflict over mating and highlights the potential importance of considering relatedness in empirical studies of sexual conflict.}, } @article {pmid21051523, year = {2010}, author = {Kaminski, G and Ravary, F and Graff, C and Gentaz, E}, title = {Firstborns' disadvantage in kinship detection.}, journal = {Psychological science}, volume = {21}, number = {12}, pages = {1746-1750}, doi = {10.1177/0956797610388045}, pmid = {21051523}, issn = {1467-9280}, mesh = {Adolescent ; Adult ; Birth Order/*psychology ; Child ; Face ; Family/*psychology ; Female ; Humans ; Male ; Recognition, Psychology ; Sibling Relations ; Young Adult ; }, abstract = {The ability to assess genetic ties is critical to defining one's own family and, in a broader context, to understanding relationships in groups of strangers. To recognize younger siblings as such, human firstborns can rely on the perinatal association of the mother with her new baby. Later-borns, who cannot rely on such an association, will by necessity actuate alternate strategies, such as recognition of facial clues set aside by firstborns. The effects of such differential early experiences deserve consideration; the development of matching abilities may be used throughout an individual's lifetime to detect other kinship types outside the family. In simple cognitive tasks based on matching face pictures, later-borns surpassed firstborns in detecting kinship among strangers; this pattern was found in populations of different ages and in two countries. This birth-order effect contrasts with the traditional cognitive advantage of firstborns. Inclusive fitness theory explains how early life history promotes specific strategies that can, in turn, permanently enhance human performance in certain domains.}, } @article {pmid21044061, year = {2011}, author = {Taylor, P and Lillicrap, T and Cownden, D}, title = {Inclusive fitness analysis on mathematical groups.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {3}, pages = {849-859}, doi = {10.1111/j.1558-5646.2010.01162.x}, pmid = {21044061}, issn = {1558-5646}, mesh = {*Biological Evolution ; *Genetic Fitness ; Genetics, Population ; *Models, Genetic ; Selection, Genetic ; }, abstract = {Recent work on the evolution of behaviour is set in a structured population, providing a systematic way to describe gene flow and behavioural interactions. To obtain analytical results one needs a structure with considerable regularity. Our results apply to such "homogeneous" structures (e.g., lattices, cycles, and island models). This regularity has been formally described by a "node-transitivity" condition but in mathematics, such internal symmetry is powerfully described by the theory of mathematical groups. Here, this theory provides elegant direct arguments for a more general version of a number of existing results. Our main result is that in large "group-structured" populations, primary fitness effects on others play no role in the evolution of the behaviour. The competitive effects of such a trait cancel the primary effects, and the inclusive fitness effect is given by the direct effect of the actor on its own fitness. This result is conditional on a number of assumptions such as (1) whether generations overlap, (2) whether offspring dispersal is symmetric, (3) whether the trait affects fecundity or survival, and (4) whether the underlying group is abelian. We formulate a number of results of this type in finite and infinite populations for both Moran and Wright-Fisher demographies.}, } @article {pmid21040069, year = {2010}, author = {Taylor, P}, title = {Birth-death symmetry in the evolution of a social trait.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {12}, pages = {2569-2578}, doi = {10.1111/j.1420-9101.2010.02122.x}, pmid = {21040069}, issn = {1420-9101}, mesh = {Altruism ; *Biological Evolution ; Fertility ; Longevity ; *Models, Biological ; Population Dynamics ; }, abstract = {Studies of the evolution of a social trait often make ecological assumptions (of population structure, life history), and thus a trait can be studied many different times with different assumptions. Here, I consider a Moran model of continuous reproduction and use an inclusive fitness analysis to investigate the relationships between fecundity or survival selection and birth-death (BD) or death-birth (DB) demography on the evolution of a social trait. A simple symmetry obtains: fecundity (respectively survival) effects under BD behave the same as survival (respectively fecundity) effects under DB. When these results are specialized to a homogeneous population, greatly simplified conditions for a positive inclusive fitness effect are obtained in both a finite and an infinite population. The results are established using the elegant formalism of mathematical group theory and are illustrated with an example of a finite population arranged in a cycle with asymmetric offspring dispersal.}, } @article {pmid20977775, year = {2010}, author = {Moore, D and Liebig, J}, title = {Mechanisms of social regulation change across colony development in an ant.}, journal = {BMC evolutionary biology}, volume = {10}, number = {}, pages = {328}, pmid = {20977775}, issn = {1471-2148}, mesh = {Analysis of Variance ; Animals ; Ants/*physiology ; Behavior, Animal/*physiology ; Eggs ; Female ; Male ; Reproduction/physiology ; *Social Behavior ; }, abstract = {BACKGROUND: Mutual policing is an important mechanism for reducing conflict in cooperative groups. In societies of ants, bees, and wasps, mutual policing of worker reproduction can evolve when workers are more closely related to the queen's sons than to the sons of workers or when the costs of worker reproduction lower the inclusive fitness of workers. During colony growth, relatedness within the colony remains the same, but the costs of worker reproduction may change. The costs of worker reproduction are predicted to be greatest in incipient colonies. If the costs associated with worker reproduction outweigh the individual direct benefits to workers, policing mechanisms as found in larger colonies may be absent in incipient colonies.

RESULTS: We investigated policing behaviour across colony growth in the ant Camponotus floridanus. In large colonies of this species, worker reproduction is policed by the destruction of worker-laid eggs. We found workers from incipient colonies do not exhibit policing behaviour, and instead tolerate all conspecific eggs. The change in policing behaviour is consistent with changes in egg surface hydrocarbons, which provide the informational basis for policing; eggs laid by queens from incipient colonies lack the characteristic hydrocarbons on the surface of eggs laid by queens from large colonies, making them chemically indistinguishable from worker-laid eggs. We also tested the response to fertility information in the context of queen tolerance. Workers from incipient colonies attacked foreign queens from large colonies; whereas workers from large colonies tolerated such queens. Workers from both incipient and large colonies attacked foreign queens from incipient colonies.

CONCLUSIONS: Our results provide novel insights into the regulation of worker reproduction in social insects at both the proximate and ultimate levels. At the proximate level, our results show that mechanisms of social regulation, such as the response to fertility signals, change dramatically over a colony's life cycle. At the ultimate level, our results emphasize the importance of factors besides relatedness in predicting the level of conflict within a colony. Our results also suggest policing may not be an important regulatory force at every stage of colony development. Changes relating to the life cycle of the colony are sufficient to account for major differences in social regulation in an insect colony. Mechanisms of conflict mediation observed in one phase of a social group's development cannot be generalized to all stages.}, } @article {pmid20975694, year = {2010}, author = {Gorrell, JC and McAdam, AG and Coltman, DW and Humphries, MM and Boutin, S}, title = {Adopting kin enhances inclusive fitness in asocial red squirrels.}, journal = {Nature communications}, volume = {1}, number = {}, pages = {22}, pmid = {20975694}, issn = {2041-1723}, mesh = {*Altruism ; Animals ; Behavior, Animal ; Female ; Male ; Sciuridae ; }, abstract = {Orphaned animals benefit from being adopted, but it is unclear why an adopting parent should incur the costs of rearing extra young. Such altruistic parental behaviour could be favoured if it is directed towards kin and the inclusive benefits of adoption exceed the costs. Here, we report the occurrence of adoption (five occurrences among 2,230 litters over 19 years) in asocial red squirrels (Tamiasciurus hudsonicus). Adoptions were always between kin, while orphans without nearby kin were never adopted. Adoptions were confined exclusively to circumstances in which the benefits to the adopted juvenile (b), discounted by the degree of relatedness between the surrogate and the orphan (r), exceeded the fitness costs of adding an extra juvenile to her litter (c), as predicted by Hamilton's rule (rb>c) for the evolution of altruism. By focusing on adoption in an asocial species, our study provides a clear test of Hamilton's rule that explains the persistence of occasional altruism in a natural mammal population.}, } @article {pmid20942969, year = {2010}, author = {Cronin, AL and Monnin, T}, title = {Self-sacrifice in 'desperado' contests between relatives.}, journal = {Frontiers in zoology}, volume = {7}, number = {}, pages = {27}, pmid = {20942969}, issn = {1742-9994}, abstract = {Intra-specific competition occurs in all animal species and can lead to escalated conflict. Overt fighting entails the risk of injury or death, and is usually avoided through the use of conventions or pre-fight assessments. However, overt fighting can be expected when value of the contest outweighs the value of the future, as contestants have little or nothing to lose. In these situations, respect for conventions and asymmetries between contestants can break down, and overt fighting becomes more likely (the desperado effect). Such conditions can arise in contests between queens over colony ownership in social insects, because the value of inheriting a colony of potentially thousands of helpers is huge and queens may have very limited alternative reproductive options. However, in social species the balance of possible outcomes may be influenced by inclusive fitness, as contestants are often relatives. Here we present a simple model based on social insects, which demonstrates that not fighting can be selectively advantageous when there is a risk posed by fighting to inclusive fitness, even when not fighting is likely to result in death. If contestants are related, a loser can still gain indirect fitness through the winner, whereas fighting introduces a risk that both queens will die and thereby obtain zero inclusive fitness. When relatedness is high and fighting poses a risk of all contestants dying, it can be advantageous to cede the contest and be killed, rather than risk everything by fighting.}, } @article {pmid20942825, year = {2010}, author = {Leigh, EG}, title = {The evolution of mutualism.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {12}, pages = {2507-2528}, doi = {10.1111/j.1420-9101.2010.02114.x}, pmid = {20942825}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; Competitive Behavior ; *Cooperative Behavior ; Ecosystem ; Models, Biological ; Symbiosis ; Trees/physiology ; }, abstract = {Like altruism, mutualism, cooperation between species, evolves only by enhancing all participants' inclusive fitness. Mutualism evolves most readily between members of different kingdoms, which pool complementary abilities for mutual benefit: some of these mutualisms represent major evolutionary innovations. Mutualism cannot persist if cheating annihilates its benefits. In long-term mutualisms, symbioses, at least one party associates with the other nearly all its life. Usually, a larger host harbours smaller symbionts. Cheating is restrained by vertical transmission, as in Buchnera; partner fidelity, as among bull-thorn acacias and protective ants; test-based choice of symbionts, as bobtail squid choose bioluminescent bacteria; or sanctioning nonperforming symbionts, as legumes punish nonperforming nitrogen-fixing bacteria. Mutualisms involving brief exchanges, as among plants and seed-dispersers, however, persist despite abundant cheating. Both symbioses and brief-exchange mutualisms have transformed whole ecosystems. These mutualisms may be steps towards ecosystems which, like Adam Smith's ideal economy, serve their members' common good.}, } @article {pmid20930829, year = {2010}, author = {Doebeli, M}, title = {Inclusive fitness is just bookkeeping.}, journal = {Nature}, volume = {467}, number = {7316}, pages = {661}, pmid = {20930829}, issn = {1476-4687}, mesh = {Animals ; Biological Evolution ; *Genetic Fitness ; *Models, Biological ; }, } @article {pmid20874811, year = {2011}, author = {Massol, F and Duputié, A and David, P and Jarne, P}, title = {Asymmetric patch size distribution leads to disruptive selection on dispersal.}, journal = {Evolution; international journal of organic evolution}, volume = {65}, number = {2}, pages = {490-500}, doi = {10.1111/j.1558-5646.2010.01143.x}, pmid = {20874811}, issn = {1558-5646}, mesh = {Animals ; Biodiversity ; *Biological Evolution ; Biota ; Computer Simulation ; Conservation of Natural Resources ; Ecosystem ; *Models, Genetic ; Selection, Genetic ; }, abstract = {Numerous models have been designed to understand how dispersal ability evolves when organisms live in a fragmented landscape. Most of them predict a single dispersal rate at evolutionary equilibrium, and when diversification of dispersal rates has been predicted, it occurs as a response to perturbation or environmental fluctuation regimes. Yet abundant variation in dispersal ability is observed in natural populations and communities, even in relatively stable environments. We show that this diversification can operate in a simple island model without temporal variability: disruptive selection on dispersal occurs when the environment consists of many small and few large patches, a common feature in natural spatial systems. This heterogeneity in patch size results in a high variability in the number of related patch mates by individual, which, in turn, triggers disruptive selection through a high per capita variance of inclusive fitness. Our study provides a likely, parsimonious and testable explanation for the diversity of dispersal rates encountered in nature. It also suggests that biological conservation policies aiming at preserving ecological communities should strive to keep the distribution of patch size sufficiently asymmetric and variable.}, } @article {pmid20849492, year = {2011}, author = {Wong, M and Balshine, S}, title = {The evolution of cooperative breeding in the African cichlid fish, Neolamprologus pulcher.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {86}, number = {2}, pages = {511-530}, doi = {10.1111/j.1469-185X.2010.00158.x}, pmid = {20849492}, issn = {1469-185X}, mesh = {Animals ; Behavior, Animal/*physiology ; *Biological Evolution ; Breeding ; Cichlids/genetics/*physiology ; Fresh Water ; Reproduction ; Sexual Behavior, Animal ; Social Behavior ; Zambia ; }, abstract = {The conundrum of why subordinate individuals assist dominants at the expense of their own direct reproduction has received much theoretical and empirical attention over the last 50 years. During this time, birds and mammals have taken centre stage as model vertebrate systems for exploring why helpers help. However, fish have great potential for enhancing our understanding of the generality and adaptiveness of helping behaviour because of the ease with which they can be experimentally manipulated under controlled laboratory and field conditions. In particular, the freshwater African cichlid, Neolamprologus pulcher, has emerged as a promising model species for investigating the evolution of cooperative breeding, with 64 papers published on this species over the past 27 years. Here we clarify current knowledge pertaining to the costs and benefits of helping in N. pulcher by critically assessing the existing empirical evidence. We then provide a comprehensive examination of the evidence pertaining to four key hypotheses for why helpers might help: (1) kin selection; (2) pay-to-stay; (3) signals of prestige; and (4) group augmentation. For each hypothesis, we outline the underlying theory, address the appropriateness of N. pulcher as a model species and describe the key predictions and associated empirical tests. For N. pulcher, we demonstrate that the kin selection and group augmentation hypotheses have received partial support. One of the key predictions of the pay-to-stay hypothesis has failed to receive any support despite numerous laboratory and field studies; thus as it stands, the evidence for this hypothesis is weak. There have been no empirical investigations addressing the key predictions of the signals of prestige hypothesis. By outlining the key predictions of the various hypotheses, and highlighting how many of these remain to be tested explicitly, our review can be regarded as a roadmap in which potential paths for future empirical research into the evolution of cooperative breeding are proposed. Overall, we clarify what is currently known about cooperative breeding in N. pulcher, address discrepancies among studies, caution against incorrect inferences that have been drawn over the years and suggest promising avenues for future research in fishes and other taxonomic groups.}, } @article {pmid20843843, year = {2011}, author = {Clune, J and Goldsby, HJ and Ofria, C and Pennock, RT}, title = {Selective pressures for accurate altruism targeting: evidence from digital evolution for difficult-to-test aspects of inclusive fitness theory.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1706}, pages = {666-674}, pmid = {20843843}, issn = {1471-2954}, mesh = {*Altruism ; Biological Evolution ; *Computer Simulation ; *Genetic Fitness ; Models, Biological ; *Selection, Genetic ; }, abstract = {Inclusive fitness theory predicts that natural selection will favour altruist genes that are more accurate in targeting altruism only to copies of themselves. In this paper, we provide evidence from digital evolution in support of this prediction by competing multiple altruist-targeting mechanisms that vary in their accuracy in determining whether a potential target for altruism carries a copy of the altruist gene. We compete altruism-targeting mechanisms based on (i) kinship (kin targeting), (ii) genetic similarity at a level greater than that expected of kin (similarity targeting), and (iii) perfect knowledge of the presence of an altruist gene (green beard targeting). Natural selection always favoured the most accurate targeting mechanism available. Our investigations also revealed that evolution did not increase the altruism level when all green beard altruists used the same phenotypic marker. The green beard altruism levels stably increased only when mutations that changed the altruism level also changed the marker (e.g. beard colour), such that beard colour reliably indicated the altruism level. For kin- and similarity-targeting mechanisms, we found that evolution was able to stably adjust altruism levels. Our results confirm that natural selection favours altruist genes that are increasingly accurate in targeting altruism to only their copies. Our work also emphasizes that the concept of targeting accuracy must include both the presence of an altruist gene and the level of altruism it produces.}, } @article {pmid20825551, year = {2010}, author = {Lehmann, L and Feldman, MW and Kaeuffer, R}, title = {Cumulative cultural dynamics and the coevolution of cultural innovation and transmission: an ESS model for panmictic and structured populations.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {11}, pages = {2356-2369}, doi = {10.1111/j.1420-9101.2010.02096.x}, pmid = {20825551}, issn = {1420-9101}, support = {GM28016/GM/NIGMS NIH HHS/United States ; }, mesh = {Computer Simulation ; *Cultural Characteristics ; *Cultural Evolution ; Fertility/physiology ; Game Theory ; Humans ; Learning/*physiology ; *Models, Biological ; }, abstract = {When individuals in a population can acquire traits through learning, each individual may express a certain number of distinct cultural traits. These traits may have been either invented by the individual himself or acquired from others in the population. Here, we develop a game theoretic model for the accumulation of cultural traits through individual and social learning. We explore how the rates of innovation, decay, and transmission of cultural traits affect the evolutionary stable (ES) levels of individual and social learning and the number of cultural traits expressed by an individual when cultural dynamics are at a steady-state. We explore the evolution of these phenotypes in both panmictic and structured population settings. Our results suggest that in panmictic populations, the ES level of learning and number of traits tend to be independent of the social transmission rate of cultural traits and is mainly affected by the innovation and decay rates. By contrast, in structured populations, where interactions occur between relatives, the ES level of learning and the number of traits per individual can be increased (relative to the panmictic case) and may then markedly depend on the transmission rate of cultural traits. This suggests that kin selection may be one additional solution to Rogers's paradox of nonadaptive culture.}, } @article {pmid20814814, year = {2011}, author = {Lass-Hennemann, J and Deuter, CE and Kuehl, LK and Schulz, A and Blumenthal, TD and Schachinger, H}, title = {Effect of facial self-resemblance on the startle response and subjective ratings of erotic stimuli in heterosexual men.}, journal = {Archives of sexual behavior}, volume = {40}, number = {5}, pages = {1007-1014}, doi = {10.1007/s10508-010-9662-8}, pmid = {20814814}, issn = {1573-2800}, mesh = {Adult ; Attention ; *Face ; Female ; Heterosexuality/*psychology ; Humans ; Male ; Middle Aged ; *Nudism ; Pattern Recognition, Visual/*physiology ; Photic Stimulation ; Reaction Time ; *Reflex, Startle ; Sexual Behavior/*psychology ; }, abstract = {Cues of kinship are predicted to increase prosocial behavior due to the benefits of inclusive fitness, but to decrease approach motivation due to the potential costs of inbreeding. Previous studies have shown that facial resemblance, a putative cue of kinship, increases prosocial behavior. However, the effects of facial resemblance on mating preferences are equivocal, with some studies finding that facial resemblance decreases sexual attractiveness ratings, while other studies show that individuals choose mates partly on the basis of similarity. To further investigate this issue, a psychophysiological measure of affective processing, the startle response, was used in this study, assuming that differences in approach motivation to erotic pictures will modulate startle. Male volunteers (n = 30) viewed 30 pictures of erotic female nudes while startle eyeblink responses were elicited by acoustic noise probes. The female nude pictures were digitally altered so that the face either resembled the male participant or another participant, or were not altered. Non-nude neutral pictures were also included. Importantly, the digital alteration was undetected by the participants. Erotic pictures were rated as being pleasant and clearly reduced startle eyeblink magnitude as compared to neutral pictures. Participants showed greater startle inhibition to self-resembling than to other-resembling or non-manipulated female nude pictures, but subjective pleasure and arousal ratings did not differ among the three erotic picture categories. Our data suggest that visual facial resemblance of opposite-sex nudes increases approach motivation in men, and that this effect was not due to their conscious evaluation of the erotic stimuli.}, } @article {pmid20812974, year = {2010}, author = {Ohtsuki, H}, title = {Evolutionary games in Wright's island model: kin selection meets evolutionary game theory.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {12}, pages = {3344-3353}, doi = {10.1111/j.1558-5646.2010.01117.x}, pmid = {20812974}, issn = {1558-5646}, mesh = {*Biological Evolution ; Game Theory ; *Genetic Fitness ; *Models, Genetic ; Population Dynamics ; Selection, Genetic ; }, abstract = {This article studies evolutionary game dynamics in Wright's infinite island model. I study a general n × n matrix game and derive a basic equation that describes the change in frequency of strategies. A close observation of this equation reveals that three distinct effects are at work: direct benefit to a focal individual, kin-selected indirect benefit to the focal individual via its relatives, and the cost caused by increased kin competition in the focal individual's natal deme. Crucial parameters are the coefficient of relatedness between two individuals and its analogue for three individuals. I provide a number of examples and show when the traditional inclusive fitness measure is recovered and when not. Results demonstrate how evolutionary game theory fits into the framework of kin selection.}, } @article {pmid20811456, year = {2010}, author = {Lee, HH and Molla, MN and Cantor, CR and Collins, JJ}, title = {Bacterial charity work leads to population-wide resistance.}, journal = {Nature}, volume = {467}, number = {7311}, pages = {82-85}, pmid = {20811456}, issn = {1476-4687}, support = {DP1 OD003644/OD/NIH HHS/United States ; /HHMI/Howard Hughes Medical Institute/United States ; DP1OD003644/OD/NIH HHS/United States ; DP1 OD003644-05/OD/NIH HHS/United States ; DP1 OD003644-04/OD/NIH HHS/United States ; }, mesh = {Anti-Bacterial Agents/metabolism/pharmacology ; *Drug Resistance, Bacterial ; Escherichia coli/*drug effects/genetics/*growth & development/metabolism ; Gene Expression Profiling ; Genome, Bacterial ; Indoles/metabolism ; Microbial Sensitivity Tests ; Microbial Viability ; Mutation ; Norfloxacin/metabolism/pharmacology ; }, abstract = {Bacteria show remarkable adaptability in the face of antibiotic therapeutics. Resistance alleles in drug target-specific sites and general stress responses have been identified in individual end-point isolates. Less is known, however, about the population dynamics during the development of antibiotic-resistant strains. Here we follow a continuous culture of Escherichia coli facing increasing levels of antibiotic and show that the vast majority of isolates are less resistant than the population as a whole. We find that the few highly resistant mutants improve the survival of the population's less resistant constituents, in part by producing indole, a signalling molecule generated by actively growing, unstressed cells. We show, through transcriptional profiling, that indole serves to turn on drug efflux pumps and oxidative-stress protective mechanisms. The indole production comes at a fitness cost to the highly resistant isolates, and whole-genome sequencing reveals that this bacterial altruism is made possible by drug-resistance mutations unrelated to indole production. This work establishes a population-based resistance mechanism constituting a form of kin selection whereby a small number of resistant mutants can, at some cost to themselves, provide protection to other, more vulnerable, cells, enhancing the survival capacity of the overall population in stressful environments.}, } @article {pmid20740005, year = {2010}, author = {Nowak, MA and Tarnita, CE and Wilson, EO}, title = {The evolution of eusociality.}, journal = {Nature}, volume = {466}, number = {7310}, pages = {1057-1062}, pmid = {20740005}, issn = {1476-4687}, support = {R01 GM078986/GM/NIGMS NIH HHS/United States ; R01 GM078986-04/GM/NIGMS NIH HHS/United States ; R01GM078986/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Behavior, Animal/*physiology ; *Biological Evolution ; Female ; Humans ; Insecta/physiology ; Male ; Models, Biological ; Selection, Genetic ; *Social Behavior ; }, abstract = {Eusociality, in which some individuals reduce their own lifetime reproductive potential to raise the offspring of others, underlies the most advanced forms of social organization and the ecologically dominant role of social insects and humans. For the past four decades kin selection theory, based on the concept of inclusive fitness, has been the major theoretical attempt to explain the evolution of eusociality. Here we show the limitations of this approach. We argue that standard natural selection theory in the context of precise models of population structure represents a simpler and superior approach, allows the evaluation of multiple competing hypotheses, and provides an exact framework for interpreting empirical observations.}, } @article {pmid20739319, year = {2011}, author = {Kachel, AF and Premo, LS and Hublin, JJ}, title = {Grandmothering and natural selection.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1704}, pages = {384-391}, pmid = {20739319}, issn = {1471-2954}, mesh = {*Biological Evolution ; Computer Simulation ; Family ; Female ; Humans ; Longevity/*genetics ; Models, Genetic ; Postmenopause/*genetics ; Reproduction/*genetics ; }, abstract = {Humans are unique among primates in that women regularly outlive their reproductive period by decades. The grandmother hypothesis proposes that natural selection increased the length of the human post-menopausal period-and, thus, extended longevity-as a result of the inclusive fitness benefits of grandmothering. However, it has yet to be demonstrated that the inclusive fitness benefits associated with grandmothering are large enough to warrant this explanation. Here, we show that the inclusive fitness benefits are too small to affect the evolution of longevity under a wide range of conditions in simulated populations. This is due in large part to the relatively weak selection that applies to women near or beyond the end of their reproductive period. However, we find that grandmothers can facilitate the evolution of a shorter reproductive period when their help decreases the weaning age of their matrilineal grandchildren. Because selection favours a shorter reproductive period in the presence of shorter interbirth intervals, this finding holds true for any form of allocare that helps mothers resume cycling more quickly. We conclude that while grandmothering is unlikely to explain human-like longevity, allocare could have played an important role in shaping other unique aspects of human life history, such as a later age at first birth and a shorter female reproductive period.}, } @article {pmid20685707, year = {2011}, author = {Setchell, JM and Vaglio, S and Abbott, KM and Moggi-Cecchi, J and Boscaro, F and Pieraccini, G and Knapp, LA}, title = {Odour signals major histocompatibility complex genotype in an Old World monkey.}, journal = {Proceedings. Biological sciences}, volume = {278}, number = {1703}, pages = {274-280}, pmid = {20685707}, issn = {1471-2954}, mesh = {Animal Communication ; Animals ; Cues ; Female ; Genetic Variation ; *Genotype ; Major Histocompatibility Complex/*genetics ; Male ; Mandrillus/*genetics/metabolism/physiology ; Mating Preference, Animal ; *Odorants ; Pheromones/chemistry/*genetics ; }, abstract = {The major histocompatibility complex (MHC) is an extraordinarily diverse cluster of genes that play a key role in the immune system. MHC gene products are also found in various body secretions, leading to the suggestion that MHC genotypes are linked to unique individual odourtypes that animals use to assess the suitability of other individuals as potential mates or social partners. We investigated the relationship between chemical odour profiles and genotype in a large, naturally reproducing population of mandrills, using gas chromatography-mass spectrometry and MHC genotyping. Odour profiles were not linked to the possession of particular MHC supertypes. Sex influenced some measures of odour diversity and dominance rank influenced some measures of odour diversity in males, but not in females. Odour similarity was strongly related to similarity at the MHC, and, in some cases, to pedigree relatedness. Our results suggest that odour provides both a cue of individual genetic quality and information against which the receiver can compare its own genotype to assess genetic similarity. These findings provide a potential mechanism underlying mate choice for genetic diversity and MHC similarity as well as kin selection.}, } @article {pmid20679114, year = {2010}, author = {de Waal, FB and Suchak, M}, title = {Prosocial primates: selfish and unselfish motivations.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {365}, number = {1553}, pages = {2711-2722}, pmid = {20679114}, issn = {1471-2970}, support = {P51 RR000165/RR/NCRR NIH HHS/United States ; RR-00165/RR/NCRR NIH HHS/United States ; }, mesh = {*Altruism ; Animals ; *Cooperative Behavior ; *Empathy ; Female ; Humans ; Male ; *Motivation ; Pan troglodytes ; }, abstract = {Non-human primates are marked by well-developed prosocial and cooperative tendencies as reflected in the way they support each other in fights, hunt together, share food and console victims of aggression. The proximate motivation behind such behaviour is not to be confused with the ultimate reasons for its evolution. Even if a behaviour is ultimately self-serving, the motivation behind it may be genuinely unselfish. A sharp distinction needs to be drawn, therefore, between (i) altruistic and cooperative behaviour with knowable benefits to the actor, which may lead actors aware of these benefits to seek them by acting cooperatively or altruistically and (ii) altruistic behaviour that offers the actor no knowable rewards. The latter is the case if return benefits occur too unpredictably, too distantly in time or are of an indirect nature, such as increased inclusive fitness. The second category of behaviour can be explained only by assuming an altruistic impulse, which-as in humans-may be born from empathy with the recipient's need, pain or distress. Empathy, a proximate mechanism for prosocial behaviour that makes one individual share another's emotional state, is biased the way one would predict from evolutionary theories of cooperation (i.e. by kinship, social closeness and reciprocation). There is increasing evidence in non-human primates (and other mammals) for this proximate mechanism as well as for the unselfish, spontaneous nature of the resulting prosocial tendencies. This paper further reviews observational and experimental evidence for the reciprocity mechanisms that underlie cooperation among non-relatives, for inequity aversion as a constraint on cooperation and on the way defection is dealt with.}, } @article {pmid20679104, year = {2010}, author = {Brosnan, SF and Bshary, R}, title = {Cooperation and deception: from evolution to mechanisms.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {365}, number = {1553}, pages = {2593-2598}, pmid = {20679104}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; *Deception ; Humans ; Models, Theoretical ; *Selection, Genetic ; }, abstract = {Nature is full of struggle, as predicted by the theory of evolution through natural selection, yet there are also paramount examples where individuals help each other. These instances of helping have been difficult to reconcile with Darwin's theory because it is not always obvious how individuals are working for their own direct benefit. Consequently, initial publications that offered solutions to subsets of the observed cases of helping, such as kin selection or reciprocity, are among the most influential and most cited papers in evolution/behavioural ecology. During the last few years, a wave of new studies and concepts has considerably advanced our understanding of the conditions under which individuals are selected to help others. On the empirical side, advances are due to stronger incorporation of the natural history of each study species and an emphasis on proximate questions regarding decision-making processes. In parallel, theorists have provided more realistic models together with an increased exploration of the importance of life history and ecology in understanding cooperation. The ideas presented by the authors of this volume represent, in many ways, the revolutionary new approach to studying behaviour which is currently underway.}, } @article {pmid20655318, year = {2011}, author = {Marshall, JA}, title = {Queller's rule ok: Comment on van Veelen 'when inclusive fitness is right and when it can be wrong'.}, journal = {Journal of theoretical biology}, volume = {270}, number = {1}, pages = {185-8; author reply 189-95}, doi = {10.1016/j.jtbi.2010.07.015}, pmid = {20655318}, issn = {1095-8541}, mesh = {Algorithms ; *Altruism ; *Biological Evolution ; *Cooperative Behavior ; Family ; *Game Theory ; Group Processes ; *Models, Biological ; }, } @article {pmid20643741, year = {2010}, author = {Frank, SA}, title = {Microbial secretor-cheater dynamics.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {365}, number = {1552}, pages = {2515-2522}, pmid = {20643741}, issn = {1471-2970}, support = {U01 GM076499/GM/NIGMS NIH HHS/United States ; U01-GM-76499/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; *Bodily Secretions ; Genetic Fitness/*genetics ; *Genetics, Population ; *Microbiological Phenomena ; *Models, Theoretical ; Mutation/genetics ; Population Dynamics ; *Selection, Genetic ; }, abstract = {Microbial secretions manipulate the environment and communicate information to neighbours. The secretions of an individual microbe typically act externally and benefit all members of the local group. Secreting imposes a cost in terms of growth, so that cheaters that do not secrete gain by sharing the benefits without paying the costs. Cheaters have been observed in several experimental and natural settings. Given that cheaters grow faster than secretors when in direct competition, what maintains the widely observed patterns of secretion? Recent theory has emphasized the genetic structure of populations, in which secretors tend to associate spatially with other secretors, reducing direct competition and allowing highly secreting groups to share mutual benefits. Such kin selection can be a powerful force favouring cooperative traits. Here, I argue that, although kin selection is a factor, the combination of mutation and demographic processes dominate in determining the relative fitness of secretors versus cheaters when measured over the full cycle of microbial life history. Key demographic factors include the local density of microbes at which secretion significantly alters the environment, the extent to which secretion enhances microbial growth and maximum local density, and the ways in which secretion alters colony survival and dispersal.}, } @article {pmid20627598, year = {2010}, author = {Saad, G}, title = {Munchausen by proxy: the dark side of parental investment theory?.}, journal = {Medical hypotheses}, volume = {75}, number = {6}, pages = {479-481}, doi = {10.1016/j.mehy.2010.04.029}, pmid = {20627598}, issn = {1532-2777}, mesh = {*Biological Evolution ; Female ; Humans ; Mothers/*psychology ; Munchausen Syndrome by Proxy/*etiology ; Personality Disorders/*complications ; }, abstract = {The parental investment hypothesis provides a parsimonious explanation for a wide range of sexually dimorphic traits and behaviors across countless species. In the human context, the hypothesis posits that in light of the differentially greater parental investment that human females provide to their offspring, they should be much more vested in the wellbeing of their children. Munchausen Syndrome by Proxy (MSbP) occurs when a caregiver feigns or causes a medical condition in a dependent (typically a child). In the great majority of cases, the biological mother is the perpetrator, which is thus deeply surprising from an evolutionary perspective. I propose that for a small sample of women (e.g., those suffering from specific personality disorders and who do not possess the necessary support from their husbands/partners), the parental investment hypothesis is usurped or subverted in the service of their narcissistic need for attention (especially from high-status male physicians). Hence, in the same way that infanticide can be explained from a Darwinian perspective (despite it being at first glance incongruent with kin selection theory), MSbP appears to be equally amenable to an evolutionary analysis. One can test the hypothesis by demonstrating that the sex-specificity of the disorder holds true irrespective of cultural setting and epoch. Furthermore, one can look at single-parental families (as a means of controlling for the otherwise differential access to children in dual-parent homes) to show that within this controlled environment, mothers will remain the greater perpetrators of MSbP.}, } @article {pmid20619817, year = {2010}, author = {Uematsu, K and Kutsukake, M and Fukatsu, T and Shimada, M and Shibao, H}, title = {Altruistic colony defense by menopausal female insects.}, journal = {Current biology : CB}, volume = {20}, number = {13}, pages = {1182-1186}, doi = {10.1016/j.cub.2010.04.057}, pmid = {20619817}, issn = {1879-0445}, mesh = {Altruism ; Animals ; Aphids/*physiology ; *Behavior, Animal ; Female ; }, abstract = {Recent studies have suggested that an extended postreproductive life span, such as life after menopause in human females, will evolve when the indirect (kin-selected) fitness benefits from altruistic behavior are greater than the direct fitness benefits from continuing reproduction. Under some conditions in which postreproductive altruism is more beneficial and/or continuing reproduction is more costly, the postreproductive life span can be shaped by natural selection. However, indirect fitness benefits during postreproductive survival have been documented mainly in intelligent mammals such as humans and cetaceans, in which elder females possess enhanced social knowledge through learning. Here we show that postreproductive females of the gall-forming aphid Quadrartus yoshinomiyai (Nipponaphidini) can gain indirect fitness benefits through their altruistic colony defense. These females cease reproduction around the time of gall opening and defend the colony by sticking themselves to intruding predators with a waxy secretion that is accumulated in their body with aging. Our results suggest that the presence of an age-related trait for altruistic behavior promotes the evolution of postreproductive altruism in this social insect via kin selection under natural selection imposed by predators.}, } @article {pmid20591868, year = {2010}, author = {Johnstone, RA and Cant, MA}, title = {The evolution of menopause in cetaceans and humans: the role of demography.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1701}, pages = {3765-3771}, pmid = {20591868}, issn = {1471-2954}, mesh = {Age Factors ; Animals ; *Biological Evolution ; Cetacea/*physiology ; Family ; Female ; Humans ; Male ; Menopause/*physiology ; *Models, Biological ; Population Dynamics ; }, abstract = {Human females stop reproducing long before they die. Among other mammals, only pilot and killer whales exhibit a comparable period of post-reproductive life. The grandmother hypothesis suggests that kin selection can favour post-reproductive survival when older females help their relatives to reproduce. But although there is an evidence that grandmothers can provide such assistance, it is puzzling why menopause should have evolved only among the great apes and toothed whales. We have previously suggested (Cant & Johnstone 2008 Proc. Natl Acad. Sci. USA 105, 5332-5336 (doi:10.1073/pnas.0711911105)) that relatedness asymmetries owing to female-biased dispersal in ancestral humans would have favoured younger females in reproductive competition with older females, predisposing our species to the evolution of menopause. But this argument appears inapplicable to menopausal cetaceans, which exhibit philopatry of both sexes combined with extra-group mating. Here, we derive general formulae for 'kinship dynamics', the age-related changes in local relatedness that occur in long-lived social organisms as a consequence of dispersal and mortality. We show that the very different social structures of great apes and menopausal whales both give rise to an increase in local relatedness with female age, favouring late-life helping. Our analysis can therefore help to explain why, of all long-lived, social mammals, it is specifically among the great apes and toothed whales that menopause and post-reproductive helping have evolved.}, } @article {pmid20585494, year = {2010}, author = {Nowbahari, E and Hollis, KL}, title = {Rescue behavior: Distinguishing between rescue, cooperation and other forms of altruistic behavior.}, journal = {Communicative & integrative biology}, volume = {3}, number = {2}, pages = {77-79}, pmid = {20585494}, issn = {1942-0889}, abstract = {Reports of rescue behavior in non-human animals are exceedingly rare, except in ants where rescue is well known, but has not been explored experimentally until recently. Although we predict that rescue behavior should be limited to circumstances in which the victim and the rescuer are highly related to one another, or in which unrelated individuals must cooperate very closely with one another, we also predict that it is likely to be far more common than the current literature would suggest. To address this oversight, we propose a rigorous definition of rescue behavior, one that helps researchers to focus on its necessary and sufficient components, at the same time that it helps to differentiate rescue behavior from cooperation and other forms of helping behavior. In this way we also hope to expand our understanding of altruism in particular and kin selection in general.}, } @article {pmid20545672, year = {2011}, author = {Nonacs, P and Hager, R}, title = {The past, present and future of reproductive skew theory and experiments.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {86}, number = {2}, pages = {271-298}, doi = {10.1111/j.1469-185X.2010.00144.x}, pmid = {20545672}, issn = {1469-185X}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Models, Biological ; Reproduction/*genetics/*physiology ; *Social Behavior ; }, abstract = {A major evolutionary question is how reproductive sharing arises in cooperatively breeding species despite the inherent reproductive conflicts in social groups. Reproductive skew theory offers one potential solution: each group member gains or is allotted inclusive fitness equal to or exceeding their expectation from reproducing on their own. Unfortunately, a multitude of skew models with conflicting predictions has led to confusion in both testing and evaluating skew theory. The confusion arises partly because one set of models (the 'transactional' type) answer the ultimate evolutionary question of what ranges of reproductive skew can yield fitness-enhancing solutions for all group members. The second set of models ('compromise') give an evolutionarily proximate, game-theoretic evolutionarily stable state (ESS) solution that determines reproductive shares based on relative competitive abilities. However, several predictions arising from compromise models require a linear payoff to increased competition and do not hold with non-linear payoffs. Given that for most species it may be very difficult or impossible to determine the true relationship between effort devoted to competition and reproductive share gained, compromise models are much less predictive than previously appreciated. Almost all skew models make one quantitative prediction (e.g. realized skew must fall within ranges predicted by transactional models), and two qualitative predictions (e.g. variation in relatedness or competitive ability across groups affects skew). A thorough review of the data finds that these three predictions are relatively rarely supported. As a general rule, therefore, the evolution of cooperative breeding appears not to be dependent on the ability of group members to monitor relatedness or competitive ability in order to adjust their behaviour dynamically to gain reproductive share. Although reproductive skew theory fails to predict within-group dynamics consistently, it does better at predicting quantitative differences in skew across populations or species. This suggests that kin selection can play a significant role in the evolution of sociality. To advance our understanding of reproductive skew will require focusing on a broader array of factors, such as the frequency of mistaken identity, delayed fitness payoffs, and selection pressures arising from across-group competition. We furthermore suggest a novel approach to investigate the sharing of reproduction that focuses on the underlying genetics of skew. A quantitative genetics approach allows the partitioning of variance in reproductive share itself or that of traits closely associated with skew into genetic and non-genetic sources. Thus, we can determine the heritability of reproductive share and infer whether it actually is the focus of natural selection. We view the 'animal model' as the most promising empirical method where the genetics of reproductive share can be directly analyzed in wild populations. In the quest to assess whether skew theory can provide a framework for understanding the evolution of sociality, quantitative genetics will be a central tool in future research.}, } @article {pmid20534616, year = {2010}, author = {Nam, KB and Simeoni, M and Sharp, SP and Hatchwell, BJ}, title = {Kinship affects investment by helpers in a cooperatively breeding bird.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1698}, pages = {3299-3306}, pmid = {20534616}, issn = {1471-2954}, mesh = {Animals ; *Behavior, Animal ; *Cooperative Behavior ; DNA/chemistry/genetics ; Family ; Female ; Genotype ; *Helping Behavior ; Linear Models ; Male ; Microsatellite Repeats ; Passeriformes/genetics/*growth & development ; Pedigree ; *Reproduction ; }, abstract = {Helping behaviour in cooperative breeding systems has been attributed to kin selection, but the relative roles of direct and indirect fitness benefits in the evolution of such systems remain a matter of debate. In theory, helpers could maximize the indirect fitness benefits of cooperation by investing more in broods with whom they are more closely related, but there is little evidence for such fine-scale adjustment in helper effort among cooperative vertebrates. In this study, we used the unusual cooperative breeding system of the long-tailed tit Aegithalos caudatus to test the hypothesis that the provisioning effort of helpers was positively correlated with their kinship to broods. We first use pedigrees and microsatellite genotypes to characterize the relatedness between helpers and breeders from a 14 year field study. We used both pedigree and genetic approaches because long-tailed tits have access to pedigree information acquired through social relationships, but any fitness consequences will be determined by genetic relatedness. We then show using both pedigrees and genetic relatedness estimates that alloparental investment by helpers increases as their relatedness to the recipients of their care increases. We conclude that kin selection has played a critical role in moulding the investment decisions of helpers in this cooperatively breeding species.}, } @article {pmid20532644, year = {2011}, author = {Wild, G}, title = {Inclusive fitness from multitype branching processes.}, journal = {Bulletin of mathematical biology}, volume = {73}, number = {5}, pages = {1028-1051}, doi = {10.1007/s11538-010-9551-2}, pmid = {20532644}, issn = {1522-9602}, mesh = {Algorithms ; Alleles ; *Biological Evolution ; Computer Simulation ; Demography ; Genetic Fitness/*physiology ; Genetics, Population/methods ; Genotype ; *Models, Genetic ; Monte Carlo Method ; Mutation/physiology ; Probability ; Selection, Genetic/physiology ; *Social Behavior ; Stochastic Processes ; }, abstract = {I use multitype branching processes to study genetic models for the evolution of social behaviour, i.e. behaviours that, when acted out, affect the success of the actor's neighbours. Here, I suppose an individual bearing a mutant copy of a gene influences the reproductive success of a neighbour by altering its own competitive ability. Approximations based on assumptions about the rareness of the mutant allele and the strength of selection allow me to formulate statements concerning the probability of mutant extinction in terms of inclusive fitness. Inclusive fitness is an idea well known to biologists and can be thought of as a sum of an individual's fitness and the fitness of each of its relatives, weighted by some measure of genetic relatedness. Previous work has led to some confusion surrounding the definition of the inclusive-fitness effect of a mutant allele when individuals carrying that allele experience demographic conditions that fluctuate randomly. In this paper, I emphasise the link between inclusive fitness and the probability of mutant extinction. I recover standard results for populations of constant size, and I show that inclusive fitness can be used to determine the short-term fate of mutants in the face of stochastic demographic fluctuations. Overall, then, I provide a connection between certain inclusive-fitness-based approaches routinely applied in theoretical studies of social evolution.}, } @article {pmid20500363, year = {2010}, author = {Rueppell, O and Hayworth, MK and Ross, NP}, title = {Altruistic self-removal of health-compromised honey bee workers from their hive.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {7}, pages = {1538-1546}, doi = {10.1111/j.1420-9101.2010.02022.x}, pmid = {20500363}, issn = {1420-9101}, mesh = {*Altruism ; Analysis of Variance ; Animals ; Bees/drug effects/*physiology ; Carbon Dioxide ; Hydroxyurea/toxicity ; Models, Biological ; Nesting Behavior/drug effects/*physiology ; Selection, Genetic/*physiology ; }, abstract = {Social insect colonies represent distinct units of selection. Most individuals evolve by kin selection and forgo individual reproduction. Instead, they display altruistic food sharing, nest maintenance and self-sacrificial colony defence. Recently, altruistic self-removal of diseased worker ants from their colony was described as another important kin-selected behaviour. Here, we report corroborating experimental evidence from honey bee foragers and theoretical analyses. We challenged honey bee foragers with prolonged CO(2) narcosis or by feeding with the cytostatic drug hydroxyurea. Both treatments resulted in increased mortality but also caused the surviving foragers to abandon their social function and remove themselves from their colony, resulting in altruistic suicide. A simple model suggests that altruistic self-removal by sick social insect workers to prevent disease transmission is expected under most biologically plausible conditions. The combined theoretical and empirical support for altruistic self-removal suggests that it may be another important kin-selected behaviour and a potentially widespread mechanism of social immunity.}, } @article {pmid20487133, year = {2010}, author = {Frank, SA}, title = {The trade-off between rate and yield in the design of microbial metabolism.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {3}, pages = {609-613}, doi = {10.1111/j.1420-9101.2010.01930.x}, pmid = {20487133}, issn = {1420-9101}, support = {U01-GM-76499/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; *Metabolism ; *Models, Genetic ; }, abstract = {Extra energy devoted to resource acquisition speeds metabolic rate, but reduces the net yield of energy. In direct competition, microbial strains with high rates of resource acquisition often outcompete strains with slower resource acquisition but higher yield, reducing the net output of the group. Here, I use mathematical models to analyse the genetic and demographic factors that tip the balance toward either rate or yield. My models clarify the widely discussed roles of kin selection and the spatial structure of populations. I also emphasize the strong effect of two previously ignored factors: demographic aspects of colony survival and reproduction strongly shape the design of metabolic rate and efficiency, and competitive mutants within long-lived colonies favour rate over yield, degrading the efficiency of the population.}, } @article {pmid20482610, year = {2010}, author = {Van Dyken, JD}, title = {The components of kin competition.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {10}, pages = {2840-2854}, pmid = {20482610}, issn = {1558-5646}, support = {R01 GM084238/GM/NIGMS NIH HHS/United States ; R01 GM084238-02/GM/NIGMS NIH HHS/United States ; 5R01GM084238-02/GM/NIGMS NIH HHS/United States ; }, mesh = {*Altruism ; Animals ; *Biological Evolution ; Competitive Behavior/*physiology ; Life Cycle Stages/genetics ; *Models, Biological ; Population Dynamics ; Selection, Genetic ; }, abstract = {It is well known that competition among kin alters the rate and often the direction of evolution in subdivided populations. Yet much remains unclear about the ecological and demographic causes of kin competition, or what role life cycle plays in promoting or ameliorating its effects. Using the multilevel Price equation, I derive a general equation for evolution in structured populations under an arbitrary intensity of kin competition. This equation partitions the effects of selection and demography, and recovers numerous previous models as special cases. I quantify the degree of kin competition, α, which explicitly depends on life cycle. I show how life cycle and demographic assumptions can be incorporated into kin selection models via α, revealing life cycles that are more or less permissive of altruism. As an example, I give closed-form results for Hamilton's rule in a three-stage life cycle. Although results are sensitive to life cycle in general, I identify three demographic conditions that give life cycle invariant results. Under the infinite island model, α is a function of the scale of density regulation and dispersal rate, effectively disentangling these two phenomena. Population viscosity per se does not impede kin selection.}, } @article {pmid20443991, year = {2010}, author = {Kingma, SA and Hall, ML and Arriero, E and Peters, A}, title = {Multiple benefits of cooperative breeding in purple-crowned fairy-wrens: a consequence of fidelity?.}, journal = {The Journal of animal ecology}, volume = {79}, number = {4}, pages = {757-768}, doi = {10.1111/j.1365-2656.2010.01697.x}, pmid = {20443991}, issn = {1365-2656}, mesh = {Animals ; Biological Evolution ; Female ; Male ; Models, Theoretical ; *Pair Bond ; Phylogeny ; Selection, Genetic ; *Songbirds ; Survival Analysis ; }, abstract = {1. Kin selection is one of the mechanisms that can explain apparent altruism by subordinate individuals in cooperatively breeding species, if subordinates boost the production of kin. We compared productivity and breeder survival in pairs with and without subordinates in a genetically monogamous cooperatively breeding bird, the purple-crowned fairy-wren Malurus coronatus. 2. Additive effects of subordinate help increased productivity. Total feeding rates to the nest were increased by two or more subordinates, and fledgling production was greater in larger groups. Not all subordinates contributed to nestling feeding, and the effect of group size was greater when non-contributors were excluded from analyses, suggesting that increased fledgling production was a direct result of help. 3. Compensatory effects of subordinate help improved breeder survival. Assisted breeders reduced their workload by 20-30%, irrespective of the number of helpers. Although re-nesting intervals were not affected by group size, reduced breeder feeding rates resulted in improved survival and breeders in larger groups survived better. 4. Subordinates and nestlings are usually progeny of the breeding pair in this species, and benefits of cooperative breeding are very different from three congeners with extremely high levels of extra-group paternity (EGP). In these Malurus, fledgling production and survival of male breeders are not enhanced in larger groups. This is consistent with the expectation that kin-selected benefits vary with relatedness, and thus levels of EGP. 5. We tested whether benefits of cooperative breeding in 37 avian species varied with levels of extra-group mating. Both direct and phylogenetically controlled comparisons showed that improvement of (male) breeder survival and enhanced productivity are more likely when fidelity is higher, as predicted when investment of subordinates correlates with relatedness to offspring. This pattern highlights the importance of considering the genetic mating system for understanding the evolution of cooperative breeding.}, } @article {pmid20424059, year = {2010}, author = {Vasey, PL and VanderLaan, DP}, title = {An adaptive cognitive dissociation between willingness to help kin and nonkin in Samoan Fa'afafine.}, journal = {Psychological science}, volume = {21}, number = {2}, pages = {292-297}, doi = {10.1177/0956797609359623}, pmid = {20424059}, issn = {1467-9280}, mesh = {Adult ; *Altruism ; Biological Evolution ; Child ; Child Care ; *Cross-Cultural Comparison ; Family/*ethnology/*psychology ; Female ; *Gender Identity ; *Helping Behavior ; Homosexuality, Male/*psychology ; Humans ; Independent State of Samoa ; Male ; *Maternal Behavior ; *Motivation ; Personality Inventory/statistics & numerical data ; Psychometrics ; Young Adult ; }, abstract = {Androphilia refers to sexual attraction and arousal to adult males, whereas gynephilia refers to sexual attraction and arousal to adult females. Previous research has demonstrated that Samoan male androphiles (known locally as fa'afafine) exhibit significantly higher altruistic tendencies toward nieces and nephews than do Samoan women and gynephilic men. The present study examined whether adaptive design features characterize the psychological mechanisms underlying fa'afafine's elevated avuncular tendencies. The association between altruistic tendencies toward nieces and nephews and altruistic tendencies toward nonkin children was significantly weaker among fa'afafine than among Samoan women and gynephilic men. We argue that this cognitive dissociation would allow fa'afafine to allocate resources to nieces and nephews in a more economical, efficient, reliable, and precise manner. These findings are consistent with the kin selection hypothesis, which suggests that androphilic males have been selected over evolutionary time to act as "helpers-in-the-nest," caring for nieces and nephews and thereby increasing their own indirect fitness.}, } @article {pmid20394666, year = {2010}, author = {McGlothlin, JW and Moore, AJ and Wolf, JB and Brodie, ED}, title = {Interacting phenotypes and the evolutionary process. III. Social evolution.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {9}, pages = {2558-2574}, doi = {10.1111/j.1558-5646.2010.01012.x}, pmid = {20394666}, issn = {1558-5646}, mesh = {Aggression ; Altruism ; Animals ; *Biological Evolution ; Models, Biological ; *Phenotype ; Population Density ; Selection, Genetic ; *Social Behavior ; Weapons ; }, abstract = {Interactions among conspecifics influence social evolution through two distinct but intimately related paths. First, they provide the opportunity for indirect genetic effects (IGEs), where genes expressed in one individual influence the expression of traits in others. Second, interactions can generate social selection when traits expressed in one individual influence the fitness of others. Here, we present a quantitative genetic model of multivariate trait evolution that integrates the effects of both IGEs and social selection, which have previously been modeled independently. We show that social selection affects evolutionary change whenever the breeding value of one individual covaries with the phenotype of its social partners. This covariance can be created by both relatedness and IGEs, which are shown to have parallel roles in determining evolutionary response. We show that social selection is central to the estimation of inclusive fitness and derive a version of Hamilton's rule showing the symmetrical effects of relatedness and IGEs on the evolution of altruism. We illustrate the utility of our approach using altruism, greenbeards, aggression, and weapons as examples. Our model provides a general predictive equation for the evolution of social phenotypes that encompasses specific cases such as kin selection and reciprocity. The parameters can be measured empirically, and we emphasize the importance of considering both IGEs and social selection, in addition to relatedness, when testing hypotheses about social evolution.}, } @article {pmid20383331, year = {2010}, author = {Bates, LA and Handford, R and Lee, PC and Njiraini, N and Poole, JH and Sayialel, K and Sayialel, S and Moss, CJ and Byrne, RW}, title = {Why do African elephants (Loxodonta africana) simulate oestrus? An analysis of longitudinal data.}, journal = {PloS one}, volume = {5}, number = {4}, pages = {e10052}, pmid = {20383331}, issn = {1932-6203}, mesh = {Animal Communication ; Animals ; Elephants/*physiology ; Estrus/*physiology/urine ; Female ; Longitudinal Studies ; Male ; Reproduction ; *Sexual Behavior, Animal ; }, abstract = {Female African elephants signal oestrus via chemicals in their urine, but they also exhibit characteristic changes to their posture, gait and behaviour when sexually receptive. Free-ranging females visually signal receptivity by holding their heads and tails high, walking with an exaggerated gait, and displaying increased tactile behaviour towards males. Parous females occasionally exhibit these visual signals at times when they are thought not to be cycling and without attracting interest from musth males. Using demographic and behavioural records spanning a continuous 28-year period, we investigated the occurrence of this "simulated" oestrus behaviour. We show that parous females in the Amboseli elephant population do simulate receptive oestrus behaviours, and this false oestrus occurs disproportionately in the presence of naïve female kin who are observed coming into oestrus for the first time. We compare several alternative hypotheses for the occurrence of this simulation: 1) false oestrus has no functional purpose (e.g., it merely results from abnormal hormonal changes); 2) false oestrus increases the reproductive success of the simulating female, by inducing sexual receptivity; and 3) false oestrus increases the inclusive fitness of the simulating female, either by increasing the access of related females to suitable males, or by encouraging appropriate oestrus behaviours from female relatives who are not responding correctly to males. Although the observed data do not fully conform to the predictions of any of these hypotheses, we rule out the first two, and tentatively suggest that parous females most likely exhibit false oestrus behaviours in order to demonstrate to naïve relatives at whom to direct their behaviour.}, } @article {pmid20375319, year = {2009}, author = {Foster, KR}, title = {A defense of sociobiology.}, journal = {Cold Spring Harbor symposia on quantitative biology}, volume = {74}, number = {}, pages = {403-418}, doi = {10.1101/sqb.2009.74.041}, pmid = {20375319}, issn = {1943-4456}, mesh = {Altruism ; Animals ; Female ; History, 20th Century ; History, 21st Century ; Humans ; Insecta/physiology ; Male ; Models, Biological ; Social Behavior ; *Sociobiology/history/statistics & numerical data/trends ; Vertebrates/physiology ; }, abstract = {To counter recent claims that sociobiology is in disarray or requires reformulation, I discuss the semantics, theory, and data that underlie the field. A historical perspective is used to identify the cause of current debates. I argue that semantic precision is required in discussing terms such as kin selection, group selection, and altruism, but once care is taken, the objections to the unity of theoretical sociobiology largely evaporate. More work is required, however, to understand group adaptation, which might be taken to be the process of optimizing phenotypes that is driven by group, rather than individual, context. From the empirical perspective, the eusocial insects with their fixed division between work and reproduction are often a sounding board in discussions. Here, one finds clear evidence for the role of kin selection and relatedness in both the origin of eusociality and its maintenance. Data from other systems including the social vertebrates, microorganisms, and even plants also support the role of relatedness and particularly family life in the evolution of cooperation and altruism. These data, however, in no way invalidate the claim that group selection is also a central process in social evolution and I discuss the empirical evidence for group selection. The foundations of sociobiology are solid and the future should build on these foundations. Exciting new areas include the importance of community and species-level selection in evolution and elucidating the molecular mechanisms that underlie social traits.}, } @article {pmid20338534, year = {2010}, author = {Cela-Conde, CJ and Burges, L and Nadal, M and Olivera, A}, title = {Altruism and fairness: Unnatural selection?.}, journal = {Comptes rendus biologies}, volume = {333}, number = {2}, pages = {174-180}, doi = {10.1016/j.crvi.2009.12.005}, pmid = {20338534}, issn = {1768-3238}, mesh = {*Altruism ; Animals ; Behavior, Animal/physiology ; Biological Evolution ; Courtship ; Family ; Female ; Group Processes ; History, 19th Century ; Humans ; Interpersonal Relations ; Male ; *Marriage ; *Morals ; *Selection, Genetic ; *Social Justice ; Sociobiology/*history ; }, abstract = {Darwin admitted that the evolution of moral phenomena such as altruism and fairness, which are usually in opposition to the maximization of individual reproductive success, was not easily accounted for by natural selection. Later, authors have proposed additional mechanisms, including kin selection, inclusive fitness, and reciprocal altruism. In the present work, we explore the extent to which sexual selection has played a role in the appearance of human moral traits. It has been suggested that because certain moral virtues, including altruism and kindness, are sexually attractive, their evolution could have been shaped by the process of sexual selection. Our review suggests that although it is possible that sexual selection played such a role, it is difficult to determine the extent of its relevance, the specific form of this influence, and its interplay with other evolutionary mechanisms.}, } @article {pmid20223978, year = {2010}, author = {West, SA and Gardner, A}, title = {Altruism, spite, and greenbeards.}, journal = {Science (New York, N.Y.)}, volume = {327}, number = {5971}, pages = {1341-1344}, doi = {10.1126/science.1178332}, pmid = {20223978}, issn = {1095-9203}, mesh = {Adaptation, Biological ; *Altruism ; Animals ; Behavior, Animal ; Competitive Behavior ; Cooperative Behavior ; Diploidy ; Female ; Genes ; *Genetic Fitness ; Haploidy ; Humans ; Male ; Reproduction ; *Selection, Genetic ; Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {Hamilton's theory of inclusive fitness showed how natural selection could lead to behaviors that decrease the relative fitness of the actor and also either benefit (altruism) or harm (spite) other individuals. However, several fundamental issues in the evolution of altruism and spite have remained contentious. Here, we show how recent work has resolved three key debates, helping clarify how Hamilton's theoretical overview links to real-world examples, in organisms ranging from bacteria to humans: Is the evolution of extreme altruism, represented by the sterile workers of social insects, driven by genetics or ecology? Does spite really exist in nature? And, can altruism be favored between individuals who are not close kin but share a "greenbeard" gene for altruism?}, } @article {pmid20164866, year = {2010}, author = {Wade, MJ and Wilson, DS and Goodnight, C and Taylor, D and Bar-Yam, Y and de Aguiar, MA and Stacey, B and Werfel, J and Hoelzer, GA and Brodie, ED and Fields, P and Breden, F and Linksvayer, TA and Fletcher, JA and Richerson, PJ and Bever, JD and Van Dyken, JD and Zee, P}, title = {Multilevel and kin selection in a connected world.}, journal = {Nature}, volume = {463}, number = {7283}, pages = {E8-9; discussion E9-10}, pmid = {20164866}, issn = {1476-4687}, support = {R01 GM084238/GM/NIGMS NIH HHS/United States ; R01 GM084238-02/GM/NIGMS NIH HHS/United States ; R01 GM092660/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Genetic Fitness/*physiology ; *Models, Biological ; Parasites/*genetics/*pathogenicity ; Selection, Genetic/*physiology ; Virulence/genetics/physiology ; }, abstract = {Wild et al. argue that the evolution of reduced virulence can be understood from the perspective of inclusive fitness, obviating the need to evoke group selection as a contributing causal factor. Although they acknowledge the mathematical equivalence of the inclusive fitness and multilevel selection approaches, they conclude that reduced virulence can be viewed entirely as an individual-level adaptation by the parasite. Here we show that their model is a well-known special case of the more general theory of multilevel selection, and that the cause of reduced virulence resides in the opposition of two processes: within-group and among-group selection. This distinction is important in light of the current controversy among evolutionary biologists in which some continue to affirm that natural selection centres only and always at the level of the individual organism or gene, despite mathematical demonstrations that evolutionary dynamics must be described by selection at various levels in the hierarchy of biological organization.}, } @article {pmid20139736, year = {2010}, author = {Dormont, L and Delle-Vedove, R and Bessière, JM and Key, MH and Schatz, B}, title = {Helping in food-deceptive orchids? A possible new mechanism maintaining polymorphism of floral signals.}, journal = {Plant signaling & behavior}, volume = {5}, number = {5}, pages = {526-527}, doi = {10.4161/psb.10967}, pmid = {20139736}, issn = {1559-2324}, mesh = {Animals ; Breeding ; Flowers/physiology ; Orchidaceae/*genetics ; Pollination ; *Polymorphism, Genetic ; *Signal Transduction ; }, abstract = {Why different colour morphs have evolved in flowering plants, and how they are maintained in populations, have long intrigued ecologists. The impact of variation in floral colour and odour (the two are frequently associated) on reproductive success remains poorly understood. In European rewardless orchids, many species occasionally show rare white-flowered individuals within populations of the common-coloured morph. In a recent study, we found that in Orchis mascula the presence of rare white-flowered morphs significantly increased the reproductive success (from 6% to 27%) of purple-flowered plants, while success of the white morph remained low. This surprising result appears due solely to floral color polymorphism, which in this species is not associated with odour polymorphism. We hypothesize that colour variation plays the key role in pollinator attraction, and that white-flowered individuals may be regarded to function as "sensory traps". We also propose that the maintenance of white-flowered mutants in O. mascula may result through kin selection, in which they act as helpers increasing the reproductive success of related purple individuals.}, } @article {pmid20129979, year = {2010}, author = {Bryden, J and Jansen, VA}, title = {The impact of clonal mixing on the evolution of social behaviour in aphids.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1688}, pages = {1651-1657}, pmid = {20129979}, issn = {1471-2954}, mesh = {Animal Migration ; Animals ; Aphids/classification/*genetics/*physiology ; Behavior, Animal/physiology ; *Biological Evolution ; Computer Simulation ; Ecosystem ; Female ; Models, Biological ; Population Dynamics ; Reproduction/genetics/physiology ; Selection, Genetic ; Social Behavior ; }, abstract = {Reports of substantial clonal mixing measured in social aphid colonies seem, on the face of it, to rule out population structure as an explanation of this enigmatic insect's social behaviour. To clarify how selection operates in aphids, and to disentangle direct and indirect fitness components, we present a model of the life cycle of a typical colony-dwelling aphid. The model incorporates ecological factors and includes a trade-off between investing in social behaviour and investing in reproduction. Our focus on inclusive fitness contrasts with previous approaches that optimize colony output. Through deriving a variant of Hamilton's rule, we show that a simple relationship can be established between the patch-carrying capacity and immigration rates into patches. Our results indicate that the levels of clonal mixing reported are not inconsistent with social behaviour. We discuss our model in terms of the evolutionary origins of social behaviour in aphids.}, } @article {pmid20116243, year = {2010}, author = {Heinze, J and Walter, B}, title = {Moribund ants leave their nests to die in social isolation.}, journal = {Current biology : CB}, volume = {20}, number = {3}, pages = {249-252}, doi = {10.1016/j.cub.2009.12.031}, pmid = {20116243}, issn = {1879-0445}, mesh = {Animals ; Ants/microbiology/*physiology ; *Biological Evolution ; Metarhizium/pathogenicity ; *Social Behavior ; }, abstract = {Animal societies provide perfect conditions for the spread of infections and are therefore expected to employ mechanisms that reduce the probability of transmitting pathogens to group members [1-4]. Death in nature rarely results from old age but commonly results from diseases. Leaving one's group to die in seclusion might be an efficient way of minimizing the risk of infecting kin. Anecdotal observations of moribund individuals deserting from their groups exist for several species, including humans (e.g., [5]), but have rarely been substantiated by quantitative analysis. Furthermore, to confirm that dying in solitude has evolved because of its altruistic benefits requires refuting the alternative explanation of pathogen manipulation of host behavior. Here we show that workers of the ant Temnothorax unifasciatus dying from fungal infection, uninfected workers whose life expectancy was reduced by exposure to 95% CO(2)[6, 7], and workers dying spontaneously in observation colonies exhibited the same suite of behavior of isolating themselves from their nestmates days or hours before death. Actively leaving the nest and breaking off all social interactions thus occurred regardless of whether individuals were infected or not. Social withdrawal might be a commonly overlooked altruistic trait serving the inclusive fitness interests of dying individuals in social animals.}, } @article {pmid20100214, year = {2010}, author = {Harcombe, W}, title = {Novel cooperation experimentally evolved between species.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {7}, pages = {2166-2172}, doi = {10.1111/j.1558-5646.2010.00959.x}, pmid = {20100214}, issn = {1558-5646}, support = {GM 57756/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; *Cooperative Behavior ; Escherichia coli K12/*metabolism ; Methionine/metabolism ; *Models, Theoretical ; Salmonella typhimurium/genetics/*metabolism ; *Selection, Genetic ; Species Specificity ; *Symbiosis ; }, abstract = {Cooperation violates the view of "nature red in tooth and claw" that prevails in our understanding of evolution, yet examples of cooperation abound. Most work has focused on maintenance of cooperation within a single species through mechanisms such as kin selection. The factors necessary for the evolutionary origin of aiding unrelated individuals such as members of another species have not been experimentally tested. Here, I demonstrate that cooperation between species can be evolved in the laboratory if (1) there is preexisting reciprocation or feedback for cooperation, and (2) reciprocation is preferentially received by cooperative genotypes. I used a two species system involving Salmonella enterica ser. Typhimurium and an Escherichia coli mutant unable to synthesize an essential amino acid. In lactose media Salmonella consumes metabolic waste from E. coli, thus creating a mechanism of reciprocation for cooperation. Growth in a spatially structured environment assured that the benefits of cooperation were preferentially received by cooperative genotypes. Salmonella evolved to aid E. coli by excreting a costly amino acid, however this novel cooperation disappeared if the waste consumption or spatial structure were removed. This study builds on previous work to demonstrate an experimental origin of interspecific cooperation, and to test the factors necessary for such interactions to arise.}, } @article {pmid20074313, year = {2010}, author = {Duncan, SI and Riechert, SE and Fitzpatrick, BM and Fordyce, JA}, title = {Relatedness and genetic structure in a socially polymorphic population of the spider Anelosimus studiosus.}, journal = {Molecular ecology}, volume = {19}, number = {4}, pages = {810-818}, doi = {10.1111/j.1365-294X.2010.04523.x}, pmid = {20074313}, issn = {1365-294X}, mesh = {Animals ; Female ; *Genetic Variation ; *Genetics, Population ; Microsatellite Repeats ; Phenotype ; Sequence Analysis, DNA ; *Social Behavior ; Spiders/*genetics ; }, abstract = {The evolution of sociality remains a challenge in evolutionary biology and a central question is whether association between kin is a critical factor favouring the evolution of cooperation. This study examines genetic structure of Anelosimus studiosus, a spider exhibiting polymorphic social behaviour. Two phenotypes have been identified: an 'asocial' phenotype with solitary female nests and a 'social' phenotype with multi-female/communal nests. To address the questions of whether these phenotypes are differentiated populations and whether cooperative individuals are closely related, we used microsatellites to analyse individuals from both communal and solitary nests. We found no evidence of differentiation between social and solitary samples, implying high rates of interbreeding. This is consistent with the hypothesis that these phenotypes coexist as a behavioural polymorphism within populations. Pairwise relatedness coefficients were used to test whether cooperating individuals are more closely related than expected by chance. Pairwise relatedness of females sharing communal webs averaged 0.25, the level expected for half-siblings and significantly more closely related than random pairs from the population. Solitary females collected at similar distances to the communal spider pairs were also more closely related than expected by chance (mean relatedness = 0.18), but less related than social pairs. These results imply that low dispersal contributes to increase likelihood of interaction between kin, but relatedness between social pairs is not explained by spatial structure alone. We propose that these phenotypes represent stages in the evolution of sociality, where viscous population structure creates opportunities for kin selection and cooperation is favoured under certain environmental conditions.}, } @article {pmid20071391, year = {2010}, author = {Mourabit, S and Rundle, SD and Spicer, JI and Sloman, KA}, title = {Alarm substance from adult zebrafish alters early embryonic development in offspring.}, journal = {Biology letters}, volume = {6}, number = {4}, pages = {525-528}, pmid = {20071391}, issn = {1744-957X}, mesh = {Analysis of Variance ; *Animal Communication ; Animals ; Embryonic Development/*drug effects ; Escape Reaction/*physiology ; Genetic Fitness/*physiology ; Heart Function Tests/drug effects ; Muscle Contraction/drug effects ; Pheromones/*pharmacology ; Species Specificity ; Video Recording ; Zebrafish/*embryology/*metabolism ; }, abstract = {Alarm substances elicit behavioural responses in a wide range of animals but effects on early embryonic development are virtually unknown. Here we investigated whether skin injury-induced alarm substances caused physiological responses in embryos produced by two Danio species (Danio rerio and Danio albolineatus). Both species showed more rapid physiological development in the presence of alarm substance, although there were subtle differences between them: D. rerio had advanced muscle contraction and heart function, whereas D. albolineatus had advanced heart function only. Hence, alarm cues from injured or dying fish may be of benefit to their offspring, inducing physiological responses and potentially increasing their inclusive fitness.}, } @article {pmid20069721, year = {2010}, author = {Fortunato, L and Archetti, M}, title = {Evolution of monogamous marriage by maximization of inclusive fitness.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {1}, pages = {149-156}, doi = {10.1111/j.1420-9101.2009.01884.x}, pmid = {20069721}, issn = {1420-9101}, mesh = {*Biological Evolution ; Female ; History, Ancient ; Humans ; Male ; Marriage/*history ; Models, Theoretical ; Sexual Behavior/*history ; Socioeconomic Factors ; }, abstract = {The majority of human societies allow polygynous marriage, and the prevalence of this practice is readily understood in evolutionary terms. Why some societies prescribe monogamous marriage is however not clear: current evolutionary explanations--that social monogamy increases within-group co-operation, giving societies an advantage in competition with other groups--conflict with the historical and ethnographic evidence. We show that, within the framework of inclusive fitness theory, monogamous marriage can be viewed as the outcome of the strategic behaviour of males and females in the allocation of resources to the next generation. Where resources are transferred across generations, social monogamy can be advantageous if partitioning of resources among the offspring of multiple wives causes a depletion of their fitness value, and/or if females grant husbands higher fidelity in exchange for exclusive investment of resources in their offspring. This may explain why monogamous marriage prevailed among the historical societies of Eurasia: here, intensive agriculture led to scarcity of land, with depletion in the value of estates through partitioning among multiple heirs. Norms promoting high paternity were common among ancient societies in the region, and may have further facilitated the establishment of social monogamy. In line with the historical and ethnographic evidence, this suggests that monogamous marriage emerged in Eurasia following the adoption of intensive agriculture, as ownership of land became critical to productive and reproductive success.}, } @article {pmid20050913, year = {2010}, author = {Lion, S and Gandon, S}, title = {Life history, habitat saturation and the evolution of fecundity and survival altruism.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {6}, pages = {1594-1606}, doi = {10.1111/j.1558-5646.2009.00933.x}, pmid = {20050913}, issn = {1558-5646}, mesh = {*Altruism ; *Biological Evolution ; Ecosystem ; *Fertility ; *Models, Biological ; Population Density ; Population Dynamics ; *Selection, Genetic ; }, abstract = {Hamilton's rule provides a general description of the conditions for the evolution of altruism. But altruism can take different forms depending on which life-history trait is affected by the helping behavior (fecundity vs. survival helping). In particular, these different forms of helping may have very different demographic consequences, which may feed back on evolution. We examine the interplay between various forms of helping and demography in viscous populations with empty sites. A key component of our analysis is the local density of empty sites experienced by a focal individual, which provides a measure of habitat saturation. Habitat saturation is shown to have contrasting effects depending on (1) whether the physiological costs and benefits of helping affect fecundity, survival or both; and (2) whether the costs of helping are paid in a density-dependent or density-independent manner. For a given level of habitat saturation and with density-dependent reproduction, we find that the conditions for the evolution of helping should be more favorable in the survival altruism life cycle with a cost on fecundity, and more stringent in the fecundity altruism life cycle with a cost on survival. More generally, our analysis stresses the importance of taking into account the feedback between population demography, life history, and kin selection when investigating the selective pressures on altruism.}, } @article {pmid20002254, year = {2010}, author = {Leigh, EG}, title = {The group selection controversy.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {1}, pages = {6-19}, doi = {10.1111/j.1420-9101.2009.01876.x}, pmid = {20002254}, issn = {1420-9101}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Genome ; *Selection, Genetic ; }, abstract = {Many thought Darwinian natural selection could not explain altruism. This error led Wynne-Edwards to explain sustainable exploitation in animals by selection against overexploiting groups. Williams riposted that selection among groups rarely overrides within-group selection. Hamilton showed that altruism can evolve through kin selection. How strongly does group selection influence evolution? Following Price, Hamilton showed how levels of selection interact: group selection prevails if Hamilton's rule applies. Several showed that group selection drove some major evolutionary transitions. Following Hamilton's lead, Queller extended Hamilton's rule, replacing genealogical relatedness by the regression on an actor's genotypic altruism of interacting neighbours' phenotypic altruism. Price's theorem shows the generality of Hamilton's rule. All instances of group selection can be viewed as increasing inclusive fitness of autosomal genomes. Nonetheless, to grasp fully how cooperation and altruism evolve, most biologists need more concrete concepts like kin selection, group selection and selection among individuals for their common good.}, } @article {pmid20002247, year = {2010}, author = {Bijma, P}, title = {Fisher's fundamental theorem of inclusive fitness and the change in fitness due to natural selection when conspecifics interact.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {1}, pages = {194-206}, doi = {10.1111/j.1420-9101.2009.01895.x}, pmid = {20002247}, issn = {1420-9101}, mesh = {Animals ; Biological Evolution ; Breeding ; *Competitive Behavior ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Competition and cooperation is fundamental to evolution by natural selection, both in animals and plants. Here, I investigate the consequences of such interactions for response in fitness due to natural selection. I provide quantitative genetic expressions for heritable variance and response in fitness due to natural selection when conspecifics interact. Results show that interactions among conspecifics generate extra heritable variance in fitness, and that interacting with kin is the key to evolutionary success because it translates the extra heritable variance into response in fitness. This work also unifies Fisher's fundamental theorem of natural selection (FTNS) and Hamilton's inclusive fitness (IF). The FTNS implies that natural selection maximizes fitness, whereas Hamilton proposed maximization of IF. This work shows that the FTNS describes the increase in IF, rather than direct fitness, at a rate equal to the additive genetic variance in fitness. Thus, Hamilton's IF and Fisher's FTNS both describe the maximization of IF.}, } @article {pmid19939839, year = {2010}, author = {Viblanc, VA and Arnaud, CM and Dobson, FS and Murie, JO}, title = {Kin selection in Columbian ground squirrels (Urocitellus columbianus): littermate kin provide individual fitness benefits.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1684}, pages = {989-994}, pmid = {19939839}, issn = {1471-2954}, mesh = {Animals ; Animals, Wild/*physiology ; Behavior, Animal/*physiology ; Biological Evolution ; *Cooperative Behavior ; Female ; Reproduction/*physiology ; Sciuridae/*physiology ; Social Behavior ; }, abstract = {Since W. D. Hamilton's seminal work on the evolution of sociality, a large body of research has accumulated on how kin selection might explain the evolution of cooperation in many group-living species. Our study examined the evolutionary basis of philopatry and cooperation; specifically, whether individuals benefit from the presence of close kin. We applied an individual fitness approach to a 16-year study of Columbian ground squirrels (Urocitellus columbianus) to investigate potential causal paths by which the presence of kin might act on individual fitness. Our results indicate that individual fitness benefits resulted from associations of philopatric female kin, and support the hypothesis that increased tolerance of proximity of kin is a proximate mechanism for these benefits. The major life-history influence of kin on individual fitness was through improved reproductive success, and this benefit may have been owing to philopatric settlement of kin that were recognized through familiarization in the natal burrow. Thus, we demonstrated an evolutionary basis necessary for ongoing kin-selected cooperation in Columbian ground squirrels, though the mechanism of familiarity may determine which kin individuals benefit from cooperative behaviours.}, } @article {pmid19929970, year = {2010}, author = {Traulsen, A}, title = {Mathematics of kin- and group-selection: formally equivalent?.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {2}, pages = {316-323}, doi = {10.1111/j.1558-5646.2009.00899.x}, pmid = {19929970}, issn = {1558-5646}, mesh = {Biological Evolution ; Game Theory ; Mathematics ; *Selection, Genetic ; }, abstract = {Evolutionary game theory is a general mathematical framework that describes the evolution of social traits. This framework forms the basis of many multilevel selection models and is also frequently used to model evolutionary dynamics on networks. Kin selection, which was initially restricted to describe social interactions between relatives, has also led to a broader mathematical approach, inclusive fitness, that can not only describe social evolution among relatives, but also in group structured populations or on social networks. It turns out that the underlying mathematics of game theory is fundamentally different from the approach of inclusive fitness. Thus, both approaches-evolutionary game theory and inclusive fitness-can be helpful to understand the evolution of social traits in group structured or spatially extended populations.}, } @article {pmid19912449, year = {2010}, author = {Frank, SA}, title = {Demography and the tragedy of the commons.}, journal = {Journal of evolutionary biology}, volume = {23}, number = {1}, pages = {32-39}, pmid = {19912449}, issn = {1420-9101}, support = {U01 GM076499/GM/NIGMS NIH HHS/United States ; U01 GM076499-04/GM/NIGMS NIH HHS/United States ; U01-GM-76499/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; *Cooperative Behavior ; Models, Theoretical ; Population Dynamics ; }, abstract = {Individual success in group-structured populations has two components. First, an individual gains by outcompeting its neighbours for local resources. Second, an individual's share of group success must be weighted by the total productivity of the group. The essence of sociality arises from the tension between selfish gains against neighbours and the associated loss that selfishness imposes by degrading the efficiency of the group. Without some force to modulate selfishness, the natural tendencies of self interest typically degrade group performance to the detriment of all. This is the tragedy of the commons. Kin selection provides the most widely discussed way in which the tragedy is overcome in biology. Kin selection arises from behavioural associations within groups caused either by genetical kinship or by other processes that correlate the behaviours of group members. Here, I emphasize demography as a second factor that may also modulate the tragedy of the commons and favour cooperative integration of groups. Each act of selfishness or cooperation in a group often influences group survival and fecundity over many subsequent generations. For example, a cooperative act early in the growth cycle of a colony may enhance the future size and survival of the colony. This time-dependent benefit can greatly increase the degree of cooperation favoured by natural selection, providing another way in which to overcome the tragedy of the commons and enhance the integration of group behaviour. I conclude that analyses of sociality must account for both the behavioural associations of kin selection theory and the demographic consequences of life history theory.}, } @article {pmid19890865, year = {2009}, author = {Vitzthum, VJ}, title = {The ecology and evolutionary endocrinology of reproduction in the human female.}, journal = {American journal of physical anthropology}, volume = {140 Suppl 49}, number = {}, pages = {95-136}, doi = {10.1002/ajpa.21195}, pmid = {19890865}, issn = {1096-8644}, mesh = {Adaptation, Physiological ; Adolescent ; Adult ; Age Factors ; Anthropology, Physical ; *Biological Evolution ; Female ; Gonadotropins/blood/urine ; Humans ; Menstruation/genetics/physiology ; Middle Aged ; Models, Theoretical ; Ovary/physiology ; Reproduction/genetics/*physiology ; Sexual Behavior ; }, abstract = {Human reproductive ecology (HRE) is the study of the mechanisms that link variation in reproductive traits with variation in local habitats. Empirical and theoretical contributions from biological anthropology, physiology, and demography have established the foundation necessary for developing a comprehensive understanding, grounded in life history theory (LHT), of temporal, individual, and populational variation in women's reproductive functioning. LHT posits that natural selection leads to the evolution of mechanisms that tend to allocate resources to the competing demands of growth, reproduction, and survival such that fitness is locally maximized. (That is, among alternative allocation patterns exhibited in a population, those having the highest inclusive fitness will become more common over generational time.) Hence, strategic modulation of reproductive effort is potentially adaptive because investment in a new conception may risk one's own survival, future reproductive opportunities, and/or current offspring survival. The hypothalamic-pituitary-ovarian (HPO) axis is the principal neuroendocrine pathway by which the human female modulates reproductive functioning according to the changing conditions in her habitat. Adjustments of reproductive investment in a potential conception are manifested in temporal and individual variation in ovarian cycle length, ovulation, hormone levels, and the probability of conception. Understanding the extent and causes of adaptive and non-adaptive variation in ovarian functioning is fundamental to ascertaining the proximate and remote determinants of human reproductive patterns. In this review I consider what is known and what still needs to be learned of the ecology of women's reproductive biology, beginning with a discussion of the principal explanatory frameworks in HRE and the biometry of ovarian functioning. Turning next to empirical studies, it is evident that marked variation between cycles, women, and populations is the norm rather than an aberration. Other than woman's age, the determinants of these differences are not well characterized, although developmental conditions, dietary practices, genetic variation, and epigenetic mechanisms have all been hypothesized to play some role. It is also evident that the reproductive functioning of women born and living in arduous conditions is not analogous to that of athletes, dieters, or even the lower end of the "normal range" of HPO functioning in wealthier populations. Contrary to the presumption that humans have low fecundity and an inefficient reproductive system, both theory and present evidence suggest that we may actually have very high fecundity and a reproductive system that has evolved to be flexible, ruthlessly efficient and, most importantly, strategic.}, } @article {pmid19889706, year = {2010}, author = {Duffy, JE and Macdonald, KS}, title = {Kin structure, ecology and the evolution of social organization in shrimp: a comparative analysis.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1681}, pages = {575-584}, pmid = {19889706}, issn = {1471-2954}, mesh = {Animals ; Bayes Theorem ; Behavior, Animal/*physiology ; Belize ; *Biological Evolution ; Body Size ; Decapoda/*physiology ; *Ecosystem ; Phylogeny ; Population Dynamics ; Porifera/*parasitology ; *Social Behavior ; Species Specificity ; *Symbiosis ; }, abstract = {Eusocial societies present a Darwinian paradox, yet they have evolved independently in insects, mole-rats and symbiotic shrimp. Historically, eusociality has been thought to arise as a response to ecological challenges, mediated by kin selection, but the role of kin selection has recently been questioned. Here we use phylogenetically independent contrasts to test the association of eusociality with ecological performance and genetic structure (via life history) among 20 species of sponge-dwelling shrimp (Synalpheus) in Belize. Consistent with hypotheses that cooperative groups enjoy an advantage in challenging habitats, we show that eusocial species are more abundant, occupy more sponges and have broader host ranges than non-social sister species, and that these patterns are robust to correction for the generally smaller body sizes of eusocial species. In contrast, body size explains less or no variation after accounting for sociality. Despite strong ecological pressures on most sponge-dwellers, however, eusociality arose only in species with non-dispersing larvae, which form family groups subject to kin selection. Thus, superior ability to hold valuable resources may favour eusociality in shrimp but close genetic relatedness is nevertheless key to its origin, as in other eusocial animals.}, } @article {pmid19889701, year = {2010}, author = {Kronauer, DJ and Schöning, C and d'Ettorre, P and Boomsma, JJ}, title = {Colony fusion and worker reproduction after queen loss in army ants.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1682}, pages = {755-763}, pmid = {19889701}, issn = {1471-2954}, mesh = {Altruism ; Animals ; Ants/*physiology ; *Behavior, Animal ; Female ; Genetics, Population ; Male ; Population Dynamics ; Reproduction/*physiology ; *Social Behavior ; }, abstract = {Theory predicts that altruism is only evolutionarily stable if it is preferentially directed towards relatives, so that any such behaviour towards seemingly unrelated individuals requires scrutiny. Queenless army ant colonies, which have anecdotally been reported to fuse with queenright foreign colonies, are such an enigmatic case. Here we combine experimental queen removal with population genetics and cuticular chemistry analyses to show that colonies of the African army ant Dorylus molestus frequently merge with neighbouring colonies after queen loss. Merging colonies often have no direct co-ancestry, but are on average probably distantly related because of overall population viscosity. The alternative of male production by orphaned workers appears to be so inefficient that residual inclusive fitness of orphaned workers might be maximized by indiscriminately merging with neighbouring colonies to increase their reproductive success. We show that worker chemical recognition profiles remain similar after queen loss, but rapidly change into a mixed colony Gestalt odour after fusion, consistent with indiscriminate acceptance of alien workers that are no longer aggressive. We hypothesize that colony fusion after queen loss might be more widespread, especially in spatially structured populations of social insects where worker reproduction is not profitable.}, } @article {pmid19889369, year = {2009}, author = {Lawrence, JG}, title = {Microbial evolution: enforcing cooperation by partial kin selection.}, journal = {Current biology : CB}, volume = {19}, number = {20}, pages = {R943-5}, doi = {10.1016/j.cub.2009.09.045}, pmid = {19889369}, issn = {1879-0445}, mesh = {*Biological Evolution ; Escherichia coli/genetics/metabolism/*physiology ; Escherichia coli Proteins/metabolism/physiology ; Gene Transfer, Horizontal ; *Microbial Interactions ; }, abstract = {How do bacterial cells mediate effective cooperation? A new paper suggests two routes: converting the uninitiated to their cause by lateral gene transfer, and enforcing cooperative behavior by killing revertants.}, } @article {pmid19878453, year = {2009}, author = {Kautz, S and Pauls, SU and Ballhorn, DJ and Lumbsch, HT and Heil, M}, title = {Polygynous supercolonies of the acacia-ant Pseudomyrmex peperi, an inferior colony founder.}, journal = {Molecular ecology}, volume = {18}, number = {24}, pages = {5180-5194}, doi = {10.1111/j.1365-294X.2009.04395.x}, pmid = {19878453}, issn = {1365-294X}, mesh = {Aggression ; Alleles ; Animals ; Ants/*genetics ; Competitive Behavior ; Evolution, Molecular ; Female ; *Genetic Variation ; *Genetics, Population ; Male ; Mexico ; Microsatellite Repeats ; Phylogeny ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; }, abstract = {In ant-plant protection mutualisms, plants provide nesting space and nutrition to defending ants. Several plant-ants are polygynous. Possessing more than one queen per colony can reduce nestmate relatedness and consequently the inclusive fitness of workers. Here, we investigated the colony structure of the obligate acacia-ant Pseudomyrmex peperi, which competes for nesting space with several congeneric and sympatric species. Pseudomyrmex peperi had a lower colony founding success than its congeners and thus, appears to be competitively inferior during the early stages of colony development. Aggression assays showed that P. peperi establishes distinct, but highly polygynous supercolonies, which can inhabit large clusters of host trees. Analysing queens, workers, males and virgin queens from two supercolonies with eight polymorphic microsatellite markers revealed a maximum of three alleles per locus within a colony and, thus, high relatedness among nestmates. Colonies had probably been founded by one singly mated queen and supercolonies resulted from intranidal mating among colony-derived males and daughter queens. This strategy allows colonies to grow by budding and to occupy individual plant clusters for time spans that are longer than an individual queen's life. Ancestral states reconstruction indicated that polygyny represents the derived state within obligate acacia-ants. We suggest that the extreme polygyny of Pseudomyrmex peperi, which is achieved by intranidal mating and thereby maintains high nestmate relatedness, might play an important role for species coexistence in a dynamic and competitive habitat.}, } @article {pmid19878410, year = {2009}, author = {Thurin, N and Aron, S}, title = {Sib-mating in the ant Plagiolepis pygmaea: adaptative inbreeding?.}, journal = {Journal of evolutionary biology}, volume = {22}, number = {12}, pages = {2481-2487}, doi = {10.1111/j.1420-9101.2009.01864.x}, pmid = {19878410}, issn = {1420-9101}, mesh = {Adaptation, Physiological/*genetics ; Aggression ; Animals ; Ants/*genetics/*physiology ; Female ; *Inbreeding ; Male ; *Sexual Behavior, Animal ; }, abstract = {Multiple functional queens in a colony (polygyny) and multiple mating by queens (polyandry) in social insects challenge kin selection, because they dilute inclusive fitness benefits from helping. Colonies of the ant Plagiolepis pygmaea brash contain several hundreds of multiply mated queens. Yet, within-colony relatedness remains unexpectedly high. This stems from low male dispersal, extensive mating among relatives and adoption of young queens in the natal colony. We investigated whether inbreeding results from workers expelling foreign males, and/or from preferential mating between related partners. Our data show that workers actively repel unrelated males entering their colony, and that queens preferentially mate with related males. These results are consistent with inclusive fitness being a driving force for inbreeding: by preventing outbreeding, workers reduce erosion of relatedness within colonies due to polygyny and polyandry. That virgin queens mate preferentially with related males could result from a long history of inbreeding, which is expected to reduce depression in species with regular sibmating.}, } @article {pmid19863794, year = {2009}, author = {Frohschammer, S and Heinze, J}, title = {A heritable component in sex ratio and caste determination in a Cardiocondyla ant.}, journal = {Frontiers in zoology}, volume = {6}, number = {}, pages = {27}, pmid = {19863794}, issn = {1742-9994}, abstract = {Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias") - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids.Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals). Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals) even when uniformly nursed by workers from another colony.Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.}, } @article {pmid19860868, year = {2009}, author = {Ruch, J and Heinrich, L and Bilde, T and Schneider, JM}, title = {Relatedness facilitates cooperation in the subsocial spider, Stegodyphus tentoriicola.}, journal = {BMC evolutionary biology}, volume = {9}, number = {}, pages = {257}, pmid = {19860868}, issn = {1471-2148}, mesh = {Animals ; Biological Evolution ; Cooperative Behavior ; Feeding Behavior ; Genetic Fitness ; Spiders/genetics/*physiology ; }, abstract = {BACKGROUND: Cooperative hunting and foraging in spiders is rare and prone to cheating such that the actions of selfish individuals negatively affect the whole group. The resulting social dilemma may be mitigated by kin selection since related individuals lose indirect fitness benefits by acting selfishly. Indeed, cooperation with genetic kin reduces the disadvantages of within-group competition in the subsocial spider Stegodyphus lineatus, supporting the hypothesis that high relatedness is an important pre-adaptation in the transition to sociality in spiders. In this study we examined the consequences of group size and relatedness on cooperative feeding in the subsocial spider S. tentoriicola, a species suggested to be at the transition to permanent sociality.

RESULTS: We formed groups of 3 and 6 spiders that were either siblings or non-siblings. We found that increasing group size negatively affected feeding efficiency but that these negative effects were reduced in sib-groups. Sib groups were more likely to feed cooperatively and all group members grew more homogenously than groups of unrelated spiders. The measured differences did not translate into differential growth or mortality during the experimental period of 8 weeks.

CONCLUSION: The combination of our results with those from previous studies indicates that the conflict between individual interests and group interests may be reduced by nepotism and that the latter promote the maintenance of the social community.}, } @article {pmid19858492, year = {2009}, author = {Akçay, E and Van Cleve, J and Feldman, MW and Roughgarden, J}, title = {A theory for the evolution of other-regard integrating proximate and ultimate perspectives.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {106}, number = {45}, pages = {19061-19066}, pmid = {19858492}, issn = {1091-6490}, support = {R01 GM028016/GM/NIGMS NIH HHS/United States ; T15 LM007033/LM/NLM NIH HHS/United States ; GM-28016/GM/NIGMS NIH HHS/United States ; LM-07033/LM/NLM NIH HHS/United States ; }, mesh = {Animals ; Behavior, Animal/*physiology ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; *Models, Theoretical ; Motivation/*physiology ; *Social Behavior ; }, abstract = {Although much previous work describes evolutionary mechanisms that promote or stabilize different social behaviors, we still have little understanding of the factors that drive animal behavior proximately. Here we present a modeling approach to answer this question. Our model rests on motivations to achieve objectives as the proximate determinants of behavior. We develop a two-tiered framework by first modeling the dynamics of a social interaction at the behavioral time scale and then find the evolutionarily stable objectives that result from the outcomes these dynamics produce. We use this framework to ask whether "other-regarding" motivations, which result from a kind of nonselfish objective, can evolve when individuals are engaged in a social interaction that entails a conflict between their material payoffs. We find that, at the evolutionarily stable state, individuals can be other-regarding in that they are motivated to increase their partners' payoff as well as their own. In contrast to previous theories, we find that such motivations can evolve because of their direct effect on fitness and do not require kin selection or a special group structure. We also derive general conditions for the evolutionary stability of other-regarding motivations. Our conditions indicate that other-regarding motivations are more likely to evolve when social interactions and behavioral objectives are both synergistic.}, } @article {pmid19846458, year = {2010}, author = {Wright, J and McDonald, PG and te Marvelde, L and Kazem, AJ and Bishop, CM}, title = {Helping effort increases with relatedness in bell miners, but 'unrelated' helpers of both sexes still provide substantial care.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1680}, pages = {437-445}, pmid = {19846458}, issn = {1471-2954}, support = {S19268/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; 5/S19 268/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Behavior, Animal ; *Breeding ; *Cooperative Behavior ; Female ; *Helping Behavior ; Male ; Nesting Behavior/*physiology ; Passeriformes/*physiology ; }, abstract = {Indirect fitness benefits from kin selection can explain why non-breeding individuals help raise the young of relatives. However, the evolution of helping by non-relatives requires direct fitness benefits, for example via group augmentation. Here, we examine nest visit rates, load sizes and prey types delivered by breeding pairs and their helpers in the cooperatively breeding bell miner (Manorina melanophrys). In this system, males remain in their natal colony while young females typically disperse, and helpers of both sexes often assist at multiple nests concurrently. We found extremely clear evidence for the expected effect of genetic relatedness on individual helping effort per nest within colonies. This positive incremental effect of kinship was facultative-i.e. largely the result of within-individual variation in helping effort. Surprisingly, no sex differences were detectable in any aspect of helping, and even non-relatives provided substantial aid. Helpers and breeders of both sexes regulated their provisioning effort by responding visit-by-visit to changes in nestling begging. Helping behaviour in bell miners therefore appears consistent with adaptive cooperative investment in the brood, and kin-selected care by relatives. Similar investment by 'unrelated' helpers of both sexes argues against direct fitness benefits, but is perhaps explained by kin selection at the colony level.}, } @article {pmid19845858, year = {2009}, author = {Buston, PM and Fauvelot, C and Wong, MY and Planes, S}, title = {Genetic relatedness in groups of the humbug damselfish Dascyllus aruanus: small, similar-sized individuals may be close kin.}, journal = {Molecular ecology}, volume = {18}, number = {22}, pages = {4707-4715}, doi = {10.1111/j.1365-294X.2009.04383.x}, pmid = {19845858}, issn = {1365-294X}, mesh = {Animals ; *Behavior, Animal ; Female ; *Genetics, Population ; Linkage Disequilibrium ; Male ; Microsatellite Repeats ; Perciformes/*genetics ; Polymorphism, Genetic ; Sequence Analysis, DNA ; *Social Behavior ; }, abstract = {Kin selection plays an important role in the evolution of social behaviour in terrestrial systems. The extent to which kin selection influences the evolution of social behaviour in marine systems is largely unexplored. Generally, it is considered that kin selection is irrelevant in marine systems, because it is assumed that the dispersing larval phase of marine organisms will break up kin associations. Here, we challenge this assumption and investigate the opportunity for kin selection in a coral reef fish: the humbug damselfish Dascyllus aruanus. This fish lives in groups composed of a large male and a number of smaller females and nonbreeders. We use 10 polymorphic microsatellite loci to assess the relatedness of 265 individuals from 35 groups. The mean coefficient of relatedness among group members is 0.01 +/- 0.04, suggesting that individuals are not associated with close relatives. However, the distribution of pairwise relatedness of individuals within groups has an overabundance of positive values, and indicates that there might be 35 pairs of close relatives within groups. Further analyses reveal that close relatives likely are similar in size and small in size, suggesting that they might have recruited together. We conclude that it is possible for kin selection to operate in D. aruanus, but kin recognition will be a prerequisite for such selection. This study reveals that individuals can be associated with close relatives, and there is a hidden potential for kin selection, during certain parts of the life cycle of coral reef fishes.}, } @article {pmid19840082, year = {2010}, author = {Schino, G and Aureli, F}, title = {The relative roles of kinship and reciprocity in explaining primate altruism.}, journal = {Ecology letters}, volume = {13}, number = {1}, pages = {45-50}, doi = {10.1111/j.1461-0248.2009.01396.x}, pmid = {19840082}, issn = {1461-0248}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Female ; *Foster Home Care ; Grooming ; Primates/*psychology ; }, abstract = {Several hypotheses have been proposed to explain the evolution of altruistic behaviours. Their relative roles in explaining actual cases of animal altruism are, however, unclear. In particular, while kin selection is widely believed to have a pervasive influence on animal behaviour, reciprocity is generally thought to be rare. Despite this general agreement, there has been no direct test comparing the relative roles of kinship and reciprocity in explaining animal altruism. In this paper, we report on the results of such a test based on a meta-analysis of allogrooming in primates, grooming being probably the most common altruistic behaviour among mammals. In direct contrast to the prevailing view, reciprocity played a much larger role than kinship in explaining primate allogrooming. These results point to a more significant role of reciprocity in the evolution of animal altruism than is generally acknowledged.}, } @article {pmid19833134, year = {2010}, author = {Taylor, PD and Grafen, A}, title = {Relatedness with different interaction configurations.}, journal = {Journal of theoretical biology}, volume = {262}, number = {3}, pages = {391-397}, doi = {10.1016/j.jtbi.2009.10.012}, pmid = {19833134}, issn = {1095-8541}, mesh = {Altruism ; Animals ; *Geography ; Humans ; Models, Genetic ; Mortality ; Mutation/genetics ; *Population Dynamics ; Reproduction ; *Social Behavior ; }, abstract = {In an inclusive fitness model of social behaviour, a key concept is that of the relatedness between two interactants. This is typically calculated with reference to a "focal" actor taken to be representative of all actors, but when there are different interaction configurations, relatedness must be constructed as an average over all such configurations. We provide an example of such a calculation in an island model with local reproduction but global mortality, leading to variable island size and hence variable numbers of individual interactions. We find that the analysis of this example significantly sharpens our understanding of relatedness. As an application, we obtain a version of Hamilton's rule for a tag-based model of altruism in a randomly mixed population. For large populations, the selective advantage of altruism is enhanced by low (but not too low) tag mutation rates and large numbers of tags. For moderate population sizes and moderate numbers of tags, we find a window of tag mutation rates with critical benefit/cost ratios of between 1 and 3.}, } @article {pmid19828549, year = {2010}, author = {Brown, SP and Taylor, PD}, title = {Joint evolution of multiple social traits: a kin selection analysis.}, journal = {Proceedings. Biological sciences}, volume = {277}, number = {1680}, pages = {415-422}, pmid = {19828549}, issn = {1471-2954}, support = {/WT_/Wellcome Trust/United Kingdom ; }, mesh = {*Altruism ; *Biological Evolution ; *Cooperative Behavior ; Humans ; Models, Genetic ; *Selection, Genetic ; *Social Behavior ; }, abstract = {General models of the evolution of cooperation, altruism and other social behaviours have focused almost entirely on single traits, whereas it is clear that social traits commonly interact. We develop a general kin-selection framework for the evolution of social behaviours in multiple dimensions. We show that whenever there are interactions among social traits new behaviours can emerge that are not predicted by one-dimensional analyses. For example, a prohibitively costly cooperative trait can ultimately be favoured owing to initial evolution in other (cheaper) social traits that in turn change the cost-benefit ratio of the original trait. To understand these behaviours, we use a two-dimensional stability criterion that can be viewed as an extension of Hamilton's rule. Our principal example is the social dilemma posed by, first, the construction and, second, the exploitation of a shared public good. We find that, contrary to the separate one-dimensional analyses, evolutionary feedback between the two traits can cause an increase in the equilibrium level of selfish exploitation with increasing relatedness, while both social (production plus exploitation) and asocial (neither) strategies can be locally stable. Our results demonstrate the importance of emergent stability properties of multidimensional social dilemmas, as one-dimensional stability in all component dimensions can conceal multidimensional instability.}, } @article {pmid19816544, year = {2009}, author = {Alvergne, A and Huchard, E and Caillaud, D and Charpentier, MJ and Setchell, JM and Ruppli, C and Féjan, D and Martinez, L and Cowlishaw, G and Raymond, M}, title = {Human Ability to Recognize Kin Visually Within Primates.}, journal = {International journal of primatology}, volume = {30}, number = {1}, pages = {199-210}, pmid = {19816544}, issn = {0164-0291}, abstract = {The assessment of relatedness is a key determinant in the evolution of social behavior in primates. Humans are able to detect kin visually in their own species using facial phenotypes, and facial resemblance in turn influences both prosocial behaviors and mating decisions. This suggests that cognitive abilities that allow facial kin detection in conspecifics have been favored in the species by kin selection. We investigated the extent to which humans are able to recognize kin visually by asking human judges to assess facial resemblance in 4 other primate species (common chimpanzees, western lowland gorillas, mandrills, and chacma baboons) on the basis of pictures of faces. Humans achieved facial interspecific kin recognition in all species except baboons. Facial resemblance is a reliable indicator of relatedness in at least chimpanzees, gorillas, and mandrills, and future work should explore if the primates themselves also share the ability to detect kin facially.}, } @article {pmid19816542, year = {2008}, author = {Smallegange, IM and Tregenza, T}, title = {Local Competition Between Foraging Relatives: Growth and Survival of Bruchid Beetle Larvae.}, journal = {Journal of insect behavior}, volume = {21}, number = {5}, pages = {375-386}, pmid = {19816542}, issn = {0892-7553}, abstract = {Kin selection theory states that when resources are limited and all else is equal, individuals will direct competition away from kin. However, when competition between relatives is completely local, as is the case in granivorous insects whose larval stages spend their lives within a single seed, this can reduce or even negate the kin-selected benefits. Instead, an increase in competition may have the same detrimental effects on individuals that forage with kin as those that forage with non-kin. In a factorial experiment we assessed the effects of relatedness and competition over food on the survival and on fitness-related traits of the bruchid beetle Callosobruchus maculatus. Relatedness of competitors did not affect the survival of larvae. Larval survival substantially decreased with increasing larval density, and we found evidence that beetles maturing at a larger size were more adversely affected by competition, resulting in lower survival rates. Furthermore, females showed a reduction in their growth rate with increasing larval density, emerging smaller after the same development time. Males increased their growth rate, emerging earlier but at a similar size when food was more limited. Our results add to the growing number of studies that fail to show a relationship between relatedness and a reduction in competition between relatives in closed systems, and emphasize the importance of the scale at which competition between relatives occurs.}, } @article {pmid19805431, year = {2009}, author = {Silk, JB}, title = {Nepotistic cooperation in non-human primate groups.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {364}, number = {1533}, pages = {3243-3254}, pmid = {19805431}, issn = {1471-2970}, mesh = {Animals ; Behavior, Animal/*physiology ; *Biological Evolution ; *Cooperative Behavior ; *Family ; Female ; Humans ; Male ; Primates/genetics/*physiology ; }, abstract = {Darwin was struck by the many similarities between humans and other primates and believed that these similarities were the product of common ancestry. He would be even more impressed by the similarities if he had known what we have learned about primates over the last 50 years. Genetic kinship has emerged as the primary organizing force in the evolution of primate social organization and the patterning of social behaviour in non-human primate groups. There are pronounced nepotistic biases across the primate order, from tiny grey mouse lemurs (Microcebus murinus) that forage alone at night but cluster with relatives to sleep during the day, to cooperatively breeding marmosets that rely on closely related helpers to rear their young, rhesus macaque (Macaca mulatta) females who acquire their mother's rank and form strict matrilineal dominance hierarchies, male howler monkeys that help their sons maintain access to groups of females and male chimpanzees (Pan troglodytes) that form lasting relationships with their brothers. As more evidence of nepotism has accumulated, important questions about the evolutionary processes underlying these kin biases have been raised. Although kin selection predicts that altruism will be biased in favour of relatives, it is difficult to assess whether primates actually conform to predictions derived from Hamilton's rule: br > c. In addition, other mechanisms, including contingent reciprocity and mutualism, could contribute to the nepotistic biases observed in non-human primate groups. There are good reasons to suspect that these processes may complement the effects of kin selection and amplify the extent of nepotistic biases in behaviour.}, } @article {pmid19805430, year = {2009}, author = {Clutton-Brock, T}, title = {Structure and function in mammalian societies.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {364}, number = {1533}, pages = {3229-3242}, pmid = {19805430}, issn = {1471-2970}, mesh = {Animals ; Behavior, Animal/*physiology ; *Biological Evolution ; Female ; Male ; Mammals/genetics/*physiology ; Reproduction/genetics/*physiology ; *Social Dominance ; }, abstract = {Traditional interpretations of the evolution of animal societies have suggested that their structure is a consequence of attempts by individuals to maximize their inclusive fitness within constraints imposed by their social and physical environments. In contrast, some recent re-interpretations have argued that many aspects of social organization should be interpreted as group-level adaptations maintained by selection operating between groups or populations. Here, I review our current understanding of the evolution of mammalian societies, focusing, in particular, on the evolution of reproductive strategies in societies where one dominant female monopolizes reproduction in each group and her offspring are reared by other group members. Recent studies of the life histories of females in these species show that dispersing females often have little chance of establishing new breeding groups and so are likely to maximize their inclusive fitness by helping related dominants to rear their offspring. As in eusocial insects, increasing group size can lead to a progressive divergence in the selection pressures operating on breeders and helpers and to increasing specialization in their behaviour and life histories. As yet, there is little need to invoke group-level adaptations in order to account for the behaviour of individuals or the structure of mammalian groups.}, } @article {pmid19805425, year = {2009}, author = {Ratnieks, FL and Helanterä, H}, title = {The evolution of extreme altruism and inequality in insect societies.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {364}, number = {1533}, pages = {3169-3179}, pmid = {19805425}, issn = {1471-2970}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; Biological Evolution ; Female ; *Genetic Fitness ; Insecta/*physiology ; Male ; }, abstract = {In eusocial organisms, some individuals specialize in reproduction and others in altruistic helping. The evolution of eusociality is, therefore, also the evolution of remarkable inequality. For example, a colony of honeybees (Apis mellifera) may contain 50 000 females all of whom can lay eggs. But 100 per cent of the females and 99.9 per cent of the males are offspring of the queen. How did such extremes evolve? Phylogenetic analyses show that high relatedness was almost certainly necessary for the origin of eusociality. However, even the highest family levels of kinship are insufficient to cause the extreme inequality seen in e.g. honeybees via 'voluntary altruism'. 'Enforced altruism' is needed, i.e. social pressures that deter individuals from attempting to reproduce. Coercion acts at two stages in an individual's life cycle. Queens are typically larger so larvae can be coerced into developing into workers by being given less food. Workers are coerced into working by 'policing', in which workers or the queen eat worker-laid eggs or aggress fertile workers. In some cases, individuals rebel, such as when stingless bee larvae develop into dwarf queens. The incentive to rebel is strong as an individual is the most closely related to its own offspring. However, because individuals gain inclusive fitness by rearing relatives, there is also a strong incentive to 'acquiesce' to social coercion. In a queenright honeybee colony, the policing of worker-laid eggs is very effective, which results in most workers working instead of attempting to reproduce. Thus, extreme altruism is due to both kinship and coercion. Altruism is frequently seen as a Darwinian puzzle but was not a puzzle that troubled Darwin. Darwin saw his difficulty in explaining how individuals that did not reproduce could evolve, given that natural selection was based on the accumulation of small heritable changes. The recognition that altruism is an evolutionary puzzle, and the solution was to wait another 100 years for William Hamilton.}, } @article {pmid19805422, year = {2009}, author = {Grafen, A}, title = {Formalizing Darwinism and inclusive fitness theory.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {364}, number = {1533}, pages = {3135-3141}, pmid = {19805422}, issn = {1471-2970}, mesh = {Animals ; *Biological Evolution ; *Genetic Fitness ; Genetics, Population ; Humans ; *Models, Genetic ; *Selection, Genetic ; Social Behavior ; }, abstract = {Inclusive fitness maximization is a basic building block for biological contributions to any theory of the evolution of society. There is a view in mathematical population genetics that nothing is caused to be maximized in the process of natural selection, but this is explained as arising from a misunderstanding about the meaning of fitness maximization. Current theoretical work on inclusive fitness is discussed, with emphasis on the author's 'formal Darwinism project'. Generally, favourable conclusions are drawn about the validity of assuming fitness maximization, but the need for continuing work is emphasized, along with the possibility that substantive exceptions may be uncovered. The formal Darwinism project aims more ambitiously to represent in a formal mathematical framework the central point of Darwin's Origin of Species, that the mechanical processes of inheritance and reproduction can give rise to the appearance of design, and it is a fitting ambition in Darwin's bicentenary year to capture his most profound discovery in the lingua franca of science.}, } @article {pmid19805058, year = {2009}, author = {Johns, PM and Howard, KJ and Breisch, NL and Rivera, A and Thorne, BL}, title = {Nonrelatives inherit colony resources in a primitive termite.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {106}, number = {41}, pages = {17452-17456}, pmid = {19805058}, issn = {1091-6490}, support = {//Howard Hughes Medical Institute/United States ; }, mesh = {Aggression ; Animals ; Cultural Evolution ; Female ; Isoptera/genetics/*physiology ; Models, Psychological ; Mole Rats/genetics/physiology ; Nesting Behavior ; Reproduction/physiology ; *Social Behavior ; Wood/parasitology ; }, abstract = {The evolution of eusociality, especially how selection would favor sterility or subfertility of most individuals within a highly social colony, is an unresolved paradox. Eusociality evolved independently in diverse taxa, including insects (all ants and termites; some bees, wasps, thrips, and beetles), snapping shrimp, and naked mole rats. Termites have received comparatively less focus than the haplodiploid Hymenoptera (ants, bees, and wasps); however, they are the only diploid group with highly complex colonies and an extraordinary diversity of castes. In this study we staged encounters between unrelated colonies of primitive dampwood termites, Zootermopsis nevadensis, mimicking natural meetings that occur under bark. During encounters, kings and/or queens were killed and surviving members merged into one colony. After encounters, members of both unrelated colonies cooperated as a single social unit. We determined the colony of origin of replacement reproductives that emerged after death of kings and/or queens. Here, we document that replacement reproductives developed from workers in either or both original colonies, inherited the merged resources of the colony, and sometimes interbred. Because this species shares many characteristics with ancestral termites, these findings demonstrate how ecological factors could have promoted the evolution of eusociality by accelerating and enhancing direct fitness opportunities of helper offspring, rendering relatedness favoring kin selection less critical.}, } @article {pmid19800234, year = {2009}, author = {Nogueira, T and Rankin, DJ and Touchon, M and Taddei, F and Brown, SP and Rocha, EP}, title = {Horizontal gene transfer of the secretome drives the evolution of bacterial cooperation and virulence.}, journal = {Current biology : CB}, volume = {19}, number = {20}, pages = {1683-1691}, pmid = {19800234}, issn = {1879-0445}, support = {/WT_/Wellcome Trust/United Kingdom ; }, mesh = {Escherichia coli/genetics/pathogenicity/*physiology ; Escherichia coli Proteins/genetics/metabolism ; *Gene Transfer, Horizontal ; Genome, Bacterial ; Microbial Interactions/*genetics ; *Models, Theoretical ; Virulence ; }, abstract = {BACKGROUND: Microbes engage in a remarkable array of cooperative behaviors, secreting shared proteins that are essential for foraging, shelter, microbial warfare, and virulence. These proteins are costly, rendering populations of cooperators vulnerable to exploitation by nonproducing cheaters arising by gene loss or migration. In such conditions, how can cooperation persist?

RESULTS: Our model predicts that differential gene mobility drives intragenomic variation in investment in cooperative traits. More mobile loci generate stronger among-individual genetic correlations at these loci (higher relatedness) and thereby allow the maintenance of more cooperative traits via kin selection. By analyzing 21 Escherichia genomes, we confirm that genes coding for secreted proteins-the secretome-are very frequently lost and gained and are associated with mobile elements. We show that homologs of the secretome are overrepresented among human gut metagenomics samples, consistent with increased relatedness at secretome loci across multiple species. The biosynthetic cost of secreted proteins is shown to be under intense selective pressure, even more than for highly expressed proteins, consistent with a cost of cooperation driving social dilemmas. Finally, we demonstrate that mobile elements are in conflict with their chromosomal hosts over the chimeric ensemble's social strategy, with mobile elements enforcing cooperation on their otherwise selfish hosts via the cotransfer of secretome genes with "mafia strategy" addictive systems (toxin-antitoxin and restriction-modification).

CONCLUSION: Our analysis matches the predictions of our model suggesting that horizontal transfer promotes cooperation, as transmission increases local genetic relatedness at mobile loci and enforces cooperation on the resident genes. As a consequence, horizontal transfer promoted by agents such as plasmids, phages, or integrons drives microbial cooperation.}, } @article {pmid19780812, year = {2010}, author = {Gardner, A and West, SA}, title = {Greenbeards.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {1}, pages = {25-38}, doi = {10.1111/j.1558-5646.2009.00842.x}, pmid = {19780812}, issn = {1558-5646}, mesh = {*Altruism ; *Genetics ; Humans ; }, abstract = {Greenbeards are genes that can identify the presence of copies of themselves in other individuals, and cause their bearer to behave nepotistically toward those individuals. In recent years, a number of examples have been discovered, and it has been suggested that greenbeards represent one of the fundamental routes to social behaviors such as cooperation. However, despite their possible theoretical and empirical importance, many basic aspects of greenbeard biology are commonly misunderstood. Here, we distinguish between four different types of greenbeard, which differ in their evolutionary dynamics. We show that all four types exist, and that they differ in the ease with which they can be empirically detected. We clarify the inclusive fitness explanation of greenbeards, and show that they are not intragenomic outlaws. Finally, we argue that although greenbeards are likely to be most common and easiest to detect in microorganisms, they are unlikely to important in organisms such as humans.}, } @article {pmid19744267, year = {2009}, author = {Alves, DA and Imperatriz-Fonseca, VL and Francoy, TM and Santos-Filho, PS and Nogueira-Neto, P and Billen, J and Wenseleers, T}, title = {The queen is dead--long live the workers: intraspecific parasitism by workers in the stingless bee Melipona scutellaris.}, journal = {Molecular ecology}, volume = {18}, number = {19}, pages = {4102-4111}, doi = {10.1111/j.1365-294X.2009.04323.x}, pmid = {19744267}, issn = {1365-294X}, mesh = {Animals ; Bees/*genetics/physiology ; Female ; Genotype ; Male ; Microsatellite Repeats ; Parasites/*genetics/physiology ; Reproduction/genetics ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; }, abstract = {Insect societies are well known for their high degree of cooperation, but their colonies can potentially be exploited by reproductive workers who lay unfertilized, male eggs, rather than work for the good of the colony. Recently, it has also been discovered that workers in bumblebees and Asian honeybees can succeed in entering and parasitizing unrelated colonies to produce their own male offspring. The aim of this study was to investigate whether such intraspecific worker parasitism might also occur in stingless bees, another group of highly social bees. Based on a large-scale genetic study of the species Melipona scutellaris, and the genotyping of nearly 600 males from 45 colonies, we show that approximately 20% of all males are workers' sons, but that around 80% of these had genotypes that were incompatible with them being the sons of workers of the resident queen. By tracking colonies over multiple generations, we show that these males were not produced by drifted workers, but rather by workers that were the offspring of a previous, superseded queen. This means that uniquely, workers reproductively parasitize the next-generation workforce. Our results are surprising given that most colonies were sampled many months after the previous queen had died and that workers normally only have a life expectancy of approximately 30 days. It also implies that reproductive workers greatly outlive all other workers. We explain our results in the context of kin selection theory, and the fact that it pays workers more from exploiting the colony if costs are carried by less related individuals.}, } @article {pmid19710066, year = {2009}, author = {Pitnick, S and Dobler, R and Hosken, DJ}, title = {Sperm length is not influenced by haploid gene expression in the flies Drosophila melanogaster and Scathophaga stercoraria.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1675}, pages = {4029-4034}, pmid = {19710066}, issn = {0962-8452}, mesh = {Animals ; Biological Evolution ; Diptera/cytology/*genetics/*metabolism ; Female ; Gene Expression Regulation ; *Haploidy ; Male ; Spermatozoa/*cytology ; }, abstract = {Recent theoretical models have postulated a role for haploid-diploid conflict and for kin selection favouring sperm cooperation and altruism in the diversification and specialization of sperm form. A critical assumption of these models-that haploid gene expression contributes to variation in sperm form-has never been demonstrated and remains contentious. By quantifying within-male variation in sperm length using crosses between males and females from populations that had been subjected to divergent experimental selection, we demonstrate that haploid gene expression does not contribute to variation in sperm length in both Drosophila melanogaster and Scathophaga stercoraria. This finding casts doubt on the importance of haploid-diploid conflict and kin selection as evolutionary influences of sperm phenotypes.}, } @article {pmid19708888, year = {2009}, author = {Du, B and Lu, X}, title = {Bi-parental vs. cooperative breeding in a passerine: fitness-maximizing strategies of males in response to risk of extra-pair paternity?.}, journal = {Molecular ecology}, volume = {18}, number = {18}, pages = {3929-3939}, doi = {10.1111/j.1365-294X.2009.04336.x}, pmid = {19708888}, issn = {1365-294X}, mesh = {Animals ; *Clutch Size ; Female ; Male ; Microsatellite Repeats ; Passeriformes/*genetics/physiology ; *Paternal Behavior ; *Reproduction ; Sequence Analysis, DNA ; *Sexual Behavior, Animal ; }, abstract = {In socially monogamous species, males that risk cuckoldry more than others might gain inclusive fitness by yielding paternity to relatives. We tested this prediction in the Tibetan ground tit Pseudopodoces humilis, an unusual facultative cooperative breeder wherein most helpers (87% males) join a mated pair shortly before clutch completion. Extra-pair paternity among bi-parental broods occurred less often (26% of broods, 9% of young) compared with cooperative broods (68%, 25%). In the former, most extra-pair sires (88%) were pair breeders unrelated to the cuckolded males, whereas in the latter, sires (87%) were mainly helpers related to the dominant males. Brood productivity did not differ between the bi-parental and cooperative breeders, but helpers' partitioning over group paternity reduced the realized reproductive success of helped males. After taking inclusive fitness into account, however, there was no difference in success of dominant males between the two social systems. One possible explanation for the differences in the rates of cuckoldry in the two systems was body size, because pair-bond males in bi-parental situations were significantly larger than those in cooperative ones. We propose two alternative strategies for males to maximize fitness: breed as a pair if large to avoid cuckoldry from helpers, or breed cooperatively if small but compromise some paternity to relatives. Our results provide an unusual route to the incidence of cooperative groups, based on constraints imposed by low competitive ability of breeding males rather than some external ecological or demographic factors.}, } @article {pmid19703222, year = {2010}, author = {Wilkins, JF}, title = {Antagonistic coevolution of two imprinted loci with pleiotropic effects.}, journal = {Evolution; international journal of organic evolution}, volume = {64}, number = {1}, pages = {142-151}, doi = {10.1111/j.1558-5646.2009.00826.x}, pmid = {19703222}, issn = {1558-5646}, mesh = {Animals ; *Biological Evolution ; Epigenesis, Genetic ; *Genomic Imprinting ; }, abstract = {At a locus subject to genomic imprinting, the expression pattern of an allele depends on its parent of origin. Typically, one allele is expressed while the other is transcriptionally silent, and natural selection at the locus will be driven by the inclusive fitness of the active allele. For some aspects of phenotype, the relevant fitness function differs between maternally and paternally derived alleles, so that maternally and paternally expressed imprinted loci become involved in an intragenomic, interlocus conflict. Here I consider the consequences of such a conflict between loci with pleiotropic effects and show that phenotypes are driven away from their optimal values, resulting in a maladaptive, but selectively favored, evolutionary trajectory. The extent to which the evolutionarily stable state departs from the optimal phenotype depends only linearly on the magnitude of the conflict, but is extremely sensitive to the relationship between the pleiotropic effects of the two loci. Thus, even a small intragenomic conflict can have significant deleterious consequences for multiple aspects of phenotype. This result has potential consequences for our understanding of disease states that occur at high frequency in the population, including several common psychological and behavioral disorders such as schizophrenia, bipolar disorder, major depression, and autism.}, } @article {pmid19688042, year = {2009}, author = {Tripet, F and Clegg, S and Elnaiem, DE and Ward, RD}, title = {Cooperative blood-feeding and the function and implications of feeding aggregations in the sand fly, Lutzomyia longipalpis (Diptera: Psychodidae).}, journal = {PLoS neglected tropical diseases}, volume = {3}, number = {8}, pages = {e503}, pmid = {19688042}, issn = {1935-2735}, abstract = {Given the importance that the evolution of cooperation bears in evolutionary biology and the social sciences, extensive theoretical work has focused on identifying conditions that promote cooperation among individuals. In insects, cooperative or altruistic interactions typically occur amongst social insects and are thus explained by kin selection. Here we provide evidence that in Lutzomia longipalpis, a small biting fly and an important vector of leishmaniasis in the New World, cooperative blood-feeding in groups of non-kin individuals results in a strong decrease in saliva expenditure. Feeding in groups also strongly affected the time taken to initiate a bloodmeal and its duration and ultimately resulted in greater fecundity. The benefits of feeding aggregations were particularly strong when flies fed on older hosts pre-exposed to sand fly bites, suggesting that flies feeding in groups may be better able to overcome their stronger immune response. These results demonstrate that, in L. longipalpis, feeding cooperatively maximizes the effects of salivary components injected into hosts to facilitate blood intake and to counteract the host immune defences. As a result, cooperating sand flies enjoy enormous fitness gains. This constitutes, to our knowledge, the first functional explanation for feeding aggregations in this species and potentially in other hematophagous insects and a rare example of cooperation amongst individuals of a non-social insects species. The evolution of cooperative group feeding in sand flies may have important implications for the epidemiology of leishmaniasis.}, } @article {pmid19667179, year = {2009}, author = {Cameron, EZ and Setsaas, TH and Linklater, WL}, title = {Social bonds between unrelated females increase reproductive success in feral horses.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {106}, number = {33}, pages = {13850-13853}, pmid = {19667179}, issn = {1091-6490}, mesh = {Animals ; Behavior, Animal ; Birth Rate ; Cooperative Behavior ; Female ; Horses ; Male ; Reproduction/*physiology ; Risk ; *Sexual Behavior, Animal ; Time Factors ; }, abstract = {In many mammals, females form close social bonds with members of their group, usually between kin. Studies of social bonds and their fitness benefits have not been investigated outside primates, and are confounded by the relatedness between individuals in primate groups. Bonds may arise from kin selection and inclusive fitness rather than through direct benefits of association. However, female equids live in long-term social groups with unrelated members. We present 4 years of behavioral data, which demonstrate that social integration between unrelated females increases both foal birth rates and survival, independent of maternal habitat quality, social group type, dominance status, and age. Also, we show that such social integration reduces harassment by males. Consequently, social integration has strong direct fitness consequences between nonrelatives, suggesting that social bonds can evolve based on these direct benefits alone. Our results support recent studies highlighting the importance of direct benefits in maintaining cooperative behavior, while controlling for the confounding influence of kinship.}, } @article {pmid19616012, year = {2009}, author = {Marshall, JA}, title = {The donation game with roles played between relatives.}, journal = {Journal of theoretical biology}, volume = {260}, number = {3}, pages = {386-391}, doi = {10.1016/j.jtbi.2009.07.008}, pmid = {19616012}, issn = {1095-8541}, mesh = {Adolescent ; Adult ; Altruism ; Evolution, Molecular ; Family Relations ; *Game Theory ; *Gift Giving ; Humans ; *Models, Genetic ; Models, Psychological ; Selection, Genetic ; }, abstract = {We consider a social game with two choices, played between two relatives, where roles are assigned to individuals so that the interaction is asymmetric. Behaviour in each of the two roles is determined by a separate genetic locus. Such asymmetric interactions between relatives, in which individuals occupy different behavioural contexts, may occur in nature, for example between adult parents and juvenile offspring. The social game considered is known to be equivalent to a donation game with non-additive payoffs, and has previously been analysed for the single locus case, both for discrete and continuous strategy traits. We present an inclusive fitness analysis of the discrete trait game with roles and recover equilibrium conditions including fixation of selfish or altruistic behaviour under both behavioural contexts, or fixation of selfish behaviour under one context and altruistic behaviour under the other context. These equilibrium solutions assume that the payoff matrices under each behavioural context are identical. The equilibria possible do depend crucially, however, on the deviation from payoff additivity that occurs when both interacting individuals act altruistically.}, } @article {pmid19608458, year = {2009}, author = {Villarreal, LP}, title = {Persistence pays: how viruses promote host group survival.}, journal = {Current opinion in microbiology}, volume = {12}, number = {4}, pages = {467-472}, pmid = {19608458}, issn = {1879-0364}, mesh = {Animals ; Carrier State ; Evolution, Molecular ; *Host-Pathogen Interactions ; Mice ; Murine hepatitis virus/physiology ; Population Dynamics ; Selection, Genetic ; *Survival ; *Virus Latency ; Virus Physiological Phenomena ; }, abstract = {Recently, we have realized that viruses numerically dominate all life. Although viruses are known to affect host survival in populations, this has not been previously evaluated in the context of host group selection. Group selection per se is not a currently accepted idea and its apparent occurrence is explained by statistical gene frequency models of kin selection. Viruses were not considered in such models. Prevalent views associate viruses and disease. Yet many viruses establish species-specific persistent, inapparent infections that are stable on an evolutionary time scale. Such persistent infections can have large effects on relative reproductive fitness of competing host populations. In this essay, I present arguments on how persistent infections can promote population survival. Mouse hepatitis virus is used as well studied examplar to re-evaluate the theoretical basis of the mouse haystack model of M Smith. This virus-centric re-examination concludes that viruses can indeed affect and promote relative group selection.}, } @article {pmid19605399, year = {2009}, author = {Wittemyer, G and Okello, JB and Rasmussen, HB and Arctander, P and Nyakaana, S and Douglas-Hamilton, I and Siegismund, HR}, title = {Where sociality and relatedness diverge: the genetic basis for hierarchical social organization in African elephants.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1672}, pages = {3513-3521}, pmid = {19605399}, issn = {0962-8452}, mesh = {Africa ; Animals ; DNA, Mitochondrial/genetics ; Elephants/*genetics/*physiology ; Female ; Genotype ; *Social Dominance ; }, abstract = {Hierarchical properties characterize elephant fission-fusion social organization whereby stable groups of individuals coalesce into higher order groups or split in a predictable manner. This hierarchical complexity is rare among animals and, as such, an examination of the factors driving its emergence offers unique insight into the evolution of social behaviour. Investigation of the genetic basis for such social affiliation demonstrates that while the majority of core social groups (second-tier affiliates) are significantly related, this is not exclusively the case. As such, direct benefits received through membership of these groups appear to be salient to their formation and maintenance. Further analysis revealed that the majority of groups in the two higher social echelons (third and fourth tiers) are typically not significantly related. The majority of third-tier members are matrilocal, carrying the same mtDNA control region haplotype, while matrilocality among fourth-tier groups was slightly less than expected at random. Comparison of results to those from a less disturbed population suggests that human depredation, leading to social disruption, altered the genetic underpinning of social relations in the study population. These results suggest that inclusive fitness benefits may crystallize elephant hierarchical social structuring along genetic lines when populations are undisturbed. However, indirect benefits are not critical to the formation and maintenance of second-, third- or fourth-tier level bonds, indicating the importance of direct benefits in the emergence of complex, hierarchical social relations among elephants. Future directions and conservation implications are discussed.}, } @article {pmid19551644, year = {2009}, author = {Santos-Filho, PS and Eterovic, A and Kleinert, AM and Imperatriz-Fonseca, VL}, title = {The number of reproductive workers in highly eusocial Hymenoptera: monogyny and monandry.}, journal = {Genetics and molecular research : GMR}, volume = {8}, number = {2}, pages = {557-570}, pmid = {19551644}, issn = {1676-5680}, mesh = {Animals ; Behavior, Animal ; Female ; Hymenoptera/*physiology ; Male ; Reproduction/*physiology ; Social Behavior ; }, abstract = {Haplodiploidy results in relatedness asymmetries between colony members of highly eusocial Hymenoptera. As a consequence, queen and reproductive workers are more related to their own sons than to each other's male offspring. Kin selection theory predicts multiple optima in male parentage: either the queen or the workers should produce all the males. Nevertheless, shared male parentage is common in highly eusocial hymenopterans. An inclusive fitness model was used to analyze the effect of the number of reproductive workers on male parentage shared by the queen and laying workers by isolating the male component from an inclusive fitness equation using the equal fitness through male condition for each pairwise combination of the three female classes comprised of the queen, laying workers and non-laying workers. The main result of the theoretical analyses showed that the fraction of males produced by workers increases asymptotically with the number of laying workers at an increasingly diminishing rate, tending to an asymptotic value of 0.67. In addition, as the number of laying workers increases, the share of male parentage converges to that of non-laying workers. The diminishing return effect on male parentage share depending on the number of reproductive workers leads us to expect the number of reproductive workers to be relatively small in a stingless bee colony, even in the absence of productivity costs. The available data confirms this hypothesis, as there is an unusually small number of reproductive workers in stingless bee colonies.}, } @article {pmid19535369, year = {2009}, author = {Kaminski, G and Dridi, S and Graff, C and Gentaz, E}, title = {Human ability to detect kinship in strangers' faces: effects of the degree of relatedness.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1670}, pages = {3193-3200}, pmid = {19535369}, issn = {0962-8452}, mesh = {Adult ; Face/*anatomy & histology ; Female ; Humans ; Male ; Pattern Recognition, Visual/*physiology ; }, abstract = {The resemblance between human faces has been shown to be a possible cue in recognizing the relatedness between parents and children, and more recently, between siblings. However, the general inclusive fitness theory proposes that kin-selective behaviours are also relevant to more distant relatives, which requires the detection of larger kinship bonds. We conducted an experiment to explore the use of facial clues by 'strangers', i.e. evaluators from a different family, to associate humans of varying degrees of relatedness. We hypothesized that the visual capacity to detect relatedness should be weaker with lower degrees of relatedness. We showed that human adults are capable of (although not very efficient at) assessing the relatedness of unrelated individuals from photographs and that visible facial cues vary according to the degree of relatedness. This sensitivity exists even for kin pair members that are more than a generation apart and have never lived together. Collectively, our findings are in agreement with emerging knowledge on the role played by facial resemblance as a kinship cue. But we have progressed further to show how the capacity to distinguish between related and non-related pairs applies to situations relevant to indirect fitness.}, } @article {pmid19519786, year = {2009}, author = {Lion, S and Gandon, S}, title = {Habitat saturation and the spatial evolutionary ecology of altruism.}, journal = {Journal of evolutionary biology}, volume = {22}, number = {7}, pages = {1487-1502}, doi = {10.1111/j.1420-9101.2009.01769.x}, pmid = {19519786}, issn = {1420-9101}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Ecology ; Ecosystem ; Models, Genetic ; }, abstract = {Under which ecological conditions should individuals help their neighbours? We investigate the effect of habitat saturation on the evolution of helping behaviours in a spatially structured population. We combine the formalisms of population genetics and spatial moment equations to tease out the effects of various physiological (direct benefits and costs of helping) and ecological parameters (such as the density of empty sites) on the selection gradient on helping. Our analysis highlights the crucial importance of demography for the evolution of helping behaviours. It shows that habitat saturation can have contrasting effects, depending on the form of competition (direct vs. indirect competition) and on the conditionality of helping. In our attempt to bridge the gap between spatial ecology and population genetics, we derive an expression for relatedness that takes into account both habitat saturation and the spatial structure of genetic variation. This analysis helps clarify discrepancies in the results obtained by previous theoretical studies. It also provides a theoretical framework taking into account the interplay between demography and kin selection, in which new biological questions can be explored.}, } @article {pmid19505481, year = {2009}, author = {Lion, S}, title = {Relatedness in spatially structured populations with empty sites: An approach based on spatial moment equations.}, journal = {Journal of theoretical biology}, volume = {260}, number = {1}, pages = {121-131}, doi = {10.1016/j.jtbi.2009.05.035}, pmid = {19505481}, issn = {1095-8541}, mesh = {Animals ; Ecosystem ; *Models, Genetic ; Pedigree ; Population Density ; Population Dynamics ; *Selection, Genetic ; }, abstract = {Taking into account the interplay between spatial ecological dynamics and selection is a major challenge in evolutionary ecology. Although inclusive fitness theory has proven to be a very useful tool to unravel the interactions between spatial genetic structuring and selection, applications of the theory usually rely on simplifying demographic assumptions. In this paper, I attempt to bridge the gap between spatial demographic models and kin selection models by providing a method to compute approximations for relatedness coefficients in a spatial model with empty sites. Using spatial moment equations, I provide an approximation of nearest-neighbour relatedness on random regular networks, and show that this approximation performs much better than the ordinary pair approximation. I discuss the connection between the relatedness coefficients I define and those used in population genetics, and sketch some potential extensions of the theory.}, } @article {pmid19500245, year = {2009}, author = {Johnson, EL and Cunningham, TW and Marriner, SM and Kovacs, JL and Hunt, BG and Bhakta, DB and Goodisman, MA}, title = {Resource allocation in a social wasp: effects of breeding system and life cycle on reproductive decisions.}, journal = {Molecular ecology}, volume = {18}, number = {13}, pages = {2908-2920}, doi = {10.1111/j.1365-294X.2009.04240.x}, pmid = {19500245}, issn = {1365-294X}, mesh = {Animals ; Female ; Genetic Markers ; Male ; Nesting Behavior ; Reproduction/genetics ; Sequence Analysis, DNA ; *Sex Ratio ; *Sexual Behavior, Animal ; Wasps/*genetics/*growth & development ; }, abstract = {Organisms must make important decisions on how to allocate resources to reproduction. We investigated allocation decisions in the social wasp Vespula maculifrons to understand how social insects make reproductive choices. We first determined how annual colonies apportioned resources to growth and reproduction by analysing developing brood. In contrast to expectations, colonies invested in both growth (workers) and reproduction (males) simultaneously. In addition, colonies showed evidence of producing males in pulses and reversing their reproductive choices by decreasing investment in males late in the season. This reversal is consistent with theory suggesting that colonies decrease production in males if fitness of late emerging males is low. To further investigate reproductive decisions within colonies, we determined if the male mates of multiply-mated queens varied in their reproductive success over time. Sperm use by queens did vary over time suggesting that male success may depend on sperm clumping within the female reproductive tract. Finally, we tested if colony sex ratio conformed to expectations under kin selection theory that nestmate relatedness would positively correlate with investment in new queens if workers controlled sex allocation. Surprisingly, the proportion of queens produced by colonies was negatively correlated with nestmate relatedness, suggesting that allocation may be shaped by advantages arising from increased genetic diversity resulting from multiple mating by queens. Overall, our study suggests that the reproductive decisions of colonies are flexible and may depend both on environmental cues arising from energetic needs of the colony and genetic cues arising from mating behaviours of queens.}, } @article {pmid19492013, year = {2009}, author = {Gohli, J and Högstedt, G}, title = {Explaining the evolution of warning coloration: secreted secondary defence chemicals may facilitate the evolution of visual aposematic signals.}, journal = {PloS one}, volume = {4}, number = {6}, pages = {e5779}, pmid = {19492013}, issn = {1932-6203}, mesh = {Adaptation, Physiological ; Animal Communication ; Animals ; Biological Evolution ; Chickens ; Computer Simulation ; Insecta ; Models, Biological ; Models, Statistical ; Models, Theoretical ; Pigmentation ; *Predatory Behavior ; Probability ; *Smell ; Stochastic Processes ; }, abstract = {Several pathways have been postulated to explain the evolution of warning coloration, which is a perplexing phenomenon. Many of these attempt to circumvent the problem of naïve predators by inferring kin selection or neophobia. Through a stochastic model, we show that a secreted secondary defence chemical can provide selective pressure, on the individual level, towards developing warning coloration. Our fundamental assumption is that increased conspicuousness will result in longer assessment periods and divergence from the predators' searching image, thus reducing the probability of a predator making mistakes. We conclude that strong olfactory signaling by means of chemical secretions can lead to the evolution of warning coloration.}, } @article {pmid19482994, year = {2009}, author = {Heinze, J and d'Ettorre, P}, title = {Honest and dishonest communication in social Hymenoptera.}, journal = {The Journal of experimental biology}, volume = {212}, number = {Pt 12}, pages = {1775-1779}, doi = {10.1242/jeb.015008}, pmid = {19482994}, issn = {0022-0949}, mesh = {*Animal Communication ; Animals ; Biological Evolution ; Female ; Fertility ; Hymenoptera/*physiology ; Male ; Sex Attractants/physiology ; Social Behavior ; Social Dominance ; }, abstract = {Communication in social insects usually serves the good of the whole society and thus increases the inclusive fitness of all individuals. Hence, cheating and dishonesty are not expected when nestmates are to be alarmed or recruited to food sources. However, kin selection predicts a conflict of interest among individuals about the partitioning of reproduction. Dishonest communication may then be advantageous. Workers usually do not lay eggs in the presence of a fertile queen, but in many species they do so when the queen is removed. This effect has been explained by manipulative, i.e. dishonest, queen control or honest fertility signalling. Numerous studies have documented qualitative and quantitative differences in the pheromone blends of reproductives and non-reproductives. We examine these data for signs of honest signalling, conflict and manipulation.}, } @article {pmid19474791, year = {2009}, author = {Wild, G and Gardner, A and West, SA}, title = {Adaptation and the evolution of parasite virulence in a connected world.}, journal = {Nature}, volume = {459}, number = {7249}, pages = {983-986}, pmid = {19474791}, issn = {1476-4687}, mesh = {*Adaptation, Physiological ; Animals ; *Biological Evolution ; Geography ; *Models, Biological ; Parasites/*pathogenicity ; Selection, Genetic ; Virulence ; }, abstract = {Adaptation is conventionally regarded as occurring at the level of the individual organism, where it functions to maximize the individual's inclusive fitness. However, it has recently been argued that empirical studies on the evolution of parasite virulence in spatial populations show otherwise. In particular, it has been claimed that the evolution of lower virulence in response to limited parasite dispersal provides proof of Wynne-Edwards's idea of adaptation at the group level. Although previous theoretical work has shown that limited dispersal can favour lower virulence, it has not clarified why, with five different suggestions having been given. Here we show that the effect of dispersal on parasite virulence can be understood entirely within the framework of inclusive fitness theory. Limited parasite dispersal favours lower parasite growth rates and, hence, reduced virulence because it (1) decreases the direct benefit of producing offspring (dispersers are worth more than non-dispersers, because they can go to patches with no or fewer parasites), and (2) increases the competition for hosts experienced by both the focal individual ('self-shading') and their relatives ('kin shading'). This demonstrates that reduced virulence can be understood as an individual-level adaptation by the parasite to maximize its inclusive fitness, and clarifies the links with virulence theory more generally.}, } @article {pmid19464296, year = {2009}, author = {Steinauer, ML and Hanelt, B and Agola, LE and Mkoji, GM and Loker, ES}, title = {Genetic structure of Schistosoma mansoni in western Kenya: The effects of geography and host sharing.}, journal = {International journal for parasitology}, volume = {39}, number = {12}, pages = {1353-1362}, pmid = {19464296}, issn = {1879-0135}, support = {R03 TW008127-02/TW/FIC NIH HHS/United States ; R01 AI044913/AI/NIAID NIH HHS/United States ; P20 RR018754-06A1/RR/NCRR NIH HHS/United States ; 1P20RR18754/RR/NCRR NIH HHS/United States ; P20 RR018754/RR/NCRR NIH HHS/United States ; R03 TW008127/TW/FIC NIH HHS/United States ; AI044913/AI/NIAID NIH HHS/United States ; R01 AI044913-10/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Female ; Fresh Water ; Genetic Markers ; Host-Parasite Interactions/*genetics ; Humans ; Kenya ; Male ; Microsatellite Repeats/*genetics ; Schistosoma mansoni/*genetics/pathogenicity ; *Schistosomiasis mansoni ; Snails/*parasitology ; Virulence/genetics ; }, abstract = {We examined the spatial structure of Schistosoma mansoni, a parasite of humans, from natural infections at two levels: across the Lake Victoria basin of Kenya and among snail hosts. Using 20 microsatellite markers we examined geographic patterns of relatedness and population structure of cercariae and found weak, but significant structure detected by some, but not all analyses. We hypothesise structure created by aggregations of clonal individuals or adherence of hosts to local transmission sites is eroded by high amounts of gene flow in the region. This finding also supports previous hypotheses concerning the evolution of drug resistance in the region. Intrasnail dynamics were investigated in the context of aggregation and kin selection theory to determine how relatedness and also sex influence host sharing and host exploitation. Cercarial production did not differ significantly between snails with one or two genotypes suggesting that mixed infections resulted in decreased individual fitness and provides a framework for reproductive competition. Coinfection patterns in snails were independent of parasite relatedness indicating that schistosomes were not aggregated according to their relatedness and that kin selection was not influencing host sharing. Additionally, host exploitation in coinfections (measured by cercarial production) was not negatively correlated with relatedness, as predicted by classical models due to increased competition and thus exploitation when parasites are unrelated. Because of the low levels of relatedness within the population, schistosomes may rarely encounter close relatives and kin selection mechanisms that influence the distribution of individuals within snails or the virulence mode of the parasites may simply have not evolved.}, } @article {pmid19457187, year = {2009}, author = {Beekman, M and Allsopp, MH and Jordan, LA and Lim, J and Oldroyd, BP}, title = {A quantitative study of worker reproduction in queenright colonies of the Cape honey bee, Apis mellifera capensis.}, journal = {Molecular ecology}, volume = {18}, number = {12}, pages = {2722-2727}, doi = {10.1111/j.1365-294X.2009.04224.x}, pmid = {19457187}, issn = {1365-294X}, mesh = {Animals ; Bees/*genetics ; Female ; Genotype ; Male ; Microsatellite Repeats ; Reproduction/genetics ; *Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {Reproduction by workers is rare in honey bee colonies that have an active queen. By not producing their own offspring and preventing other workers from producing theirs, workers are thought to increase their inclusive fitness due to their higher average relatedness towards queen-produced male offspring compared with worker-produced male offspring. But there is one exception. Workers of the Cape honey bee, Apis mellifera capensis, are able to produce diploid female offspring via thelytokous parthenogenesis and thus produce clones of themselves. As a result, worker reproduction and tolerance towards worker-produced offspring is expected to be more permissive than in arrhenotokous (sub)species where worker offspring are male. Here we quantify the extent to which A. m. capensis workers contribute to reproduction in queenright colonies using microsatellite analyses of pre-emergent brood. We show that workers produced 10.5% of workers and 0.48% of drones. Most of the workers' contribution towards the production of new workers coincided with the colonies producing new queens during reproductive swarming.}, } @article {pmid19443503, year = {2009}, author = {Bourke, AF}, title = {The kin structure of sexual interactions.}, journal = {Biology letters}, volume = {5}, number = {5}, pages = {689-692}, pmid = {19443503}, issn = {1744-957X}, mesh = {Animals ; Biological Evolution ; Breeding ; Female ; Male ; Reproduction/*genetics ; Sex Ratio ; *Sexual Behavior, Animal ; }, abstract = {The origin of sexual reproduction involved the evolution of zygotes from separate genomes and, like other social processes, should therefore be amenable to analysis using kin selection theory. I consider how kin structure affects sexual interactions in three contexts--the evolution of sexual reproduction, sex allocation and sexual conflict. Kin structure helps explain the even-handed replication of paternal and maternal genes under outbreeding. Under inbreeding, it predicts altruistic failure to replicate by one half of the diploid genome. Kin structure predicts optimal sex ratios and potential conflicts over sex ratio within social groups and individuals. Sexual conflict predictably occurs as a function of (i) the probability that current sexual partners will reproduce together in future and (ii) between-partner relatedness. I conclude that systematically analysing the kin structure of sexual interactions helps illuminate their evolution.}, } @article {pmid19419985, year = {2009}, author = {Richard, M and Losdat, S and Lecomte, J and de Fraipont, M and Clobert, J}, title = {Optimal level of inbreeding in the common lizard.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1668}, pages = {2779-2786}, pmid = {19419985}, issn = {0962-8452}, mesh = {Animals ; Ecosystem ; Female ; *Inbreeding ; Lizards/*genetics/*physiology ; Male ; Sexual Behavior, Animal/physiology ; }, abstract = {Mate choice with regard to genetic similarity has been rarely considered as a dynamic process. We examined this possibility in breeding populations of the common lizard (Lacerta vivipara) kept for several years in semi-natural conditions. We investigated whether they displayed a pattern of mate choice according to the genetic similarity and whether it was context-dependent. Mate choice depended on genetic similarity with the partner and also on age and condition. There was no systematic avoidance of inbreeding. Females of intermediate ages, more monogamous, did not mate with genetically similar partners, whereas younger and older females, more polyandrous, did but highest clutch proportions were associated with intermediate values of pair-relatedness. These results indicate dynamic mate choice, suggesting that individuals of different phenotypes select their partners in different ways according to their genetic similarity. We consider our results in the light of diverse and apparently contradictory theories concerning genetic compatibility, and particularly, optimal inbreeding and inclusive fitness.}, } @article {pmid19418529, year = {2009}, author = {Mace, R and Colleran, H}, title = {Kin influence on the decision to start using modern contraception: A longitudinal study from rural Gambia.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {21}, number = {4}, pages = {472-477}, doi = {10.1002/ajhb.20940}, pmid = {19418529}, issn = {1520-6300}, mesh = {Adolescent ; Adult ; Age Factors ; Aged ; Aged, 80 and over ; Anthropology, Cultural ; Biological Evolution ; Contraception Behavior/*ethnology ; *Cultural Characteristics ; Ecological and Environmental Phenomena ; *Family Relations ; Female ; Fertility ; Gambia ; Humans ; Longitudinal Studies ; Middle Aged ; Rural Population ; Sociology ; }, abstract = {In earlier work in rural Gambia, we found that kin influence reproductive success: matrilineal kin, especially mothers, maternal grandmothers and unmarried older sisters all helped to promote the survival and nutrition of young children; in contrast patrilineal kin, especially husband's mother, promoted fertility. These differing influences of maternal and paternal lineage are predicted on the basis of kin selection and sexual conflict theory, because the costs of reproduction fall more heavily on the mother than the father. These studies covered the period 1950-1975, when this population was essentially "natural fertility, natural mortality." It is not possible to tell whether these effects were due to kin influencing active reproductive decision-making, or due to indirect effects such as kin improving nutrition by helping. Since 1976, modern contraception has become available in this community. In an analysis of the behavioral ecology of the decision to start using modern contraception, we found that high parity for your age was a key determinant of the decision, as was village and calendar year. Here, we examine whether the presence or absence of kin and also whether the contraceptive status of kin influenced the decision to start using contraception. We find little evidence that kin directly influence contraceptive uptake, either by their presence/absence or as models for social learning. However, death of a first husband (i.e., widowhood) does accelerate contraceptive uptake. We discuss our results from an evolutionary demography perspective, in particular regarding theories of sexual conflict, biased cultural transmission, and social learning.}, } @article {pmid19416733, year = {2009}, author = {Holmes, MM and Goldman, BD and Goldman, SL and Seney, ML and Forger, NG}, title = {Neuroendocrinology and sexual differentiation in eusocial mammals.}, journal = {Frontiers in neuroendocrinology}, volume = {30}, number = {4}, pages = {519-533}, pmid = {19416733}, issn = {1095-6808}, support = {F31 NS058258/NS/NINDS NIH HHS/United States ; K02 MH072825/MH/NIMH NIH HHS/United States ; K02 MH072825-05/MH/NIMH NIH HHS/United States ; }, mesh = {Animals ; Behavior, Animal/*physiology ; Brain/anatomy & histology/physiology ; *Neuroendocrinology ; Rats ; Reproduction/physiology ; *Sex Characteristics ; *Sex Determination Processes ; Sexual Behavior, Animal/*physiology ; *Social Behavior ; }, abstract = {Sexual differentiation of the mammalian nervous system has been studied intensively for over 25 years. Most of what we know, however, comes from work on relatively non-social species in which direct reproduction (i.e., production of offspring) is virtually the only route to reproductive success. In social species, an individual's inclusive fitness may include contributions to the gene pool that are achieved by supporting the reproductive efforts of close relatives; this feature is most evident in eusocial organisms. Here, we review what is known about neuroendocrine mechanisms, sexual differentiation, and effects of social status on the brain and spinal cord in two eusocial mammals: the naked mole-rat and Damaraland mole-rat. These small rodents exhibit the most rigidly organized reproductive hierarchy among mammals, with reproduction suppressed in a majority of individuals. Our findings suggest that eusociality may be associated with a relative lack of sex differences and a reduced influence of gonadal hormones on some functions to which these hormones are usually tightly linked. We also identify neural changes accompanying a change in social and reproductive status, and discuss the implications of our findings for understanding the evolution of sex differences and the neuroendocrinology of reproductive suppression.}, } @article {pmid19410582, year = {2009}, author = {van Veelen, M}, title = {Group selection, kin selection, altruism and cooperation: when inclusive fitness is right and when it can be wrong.}, journal = {Journal of theoretical biology}, volume = {259}, number = {3}, pages = {589-600}, doi = {10.1016/j.jtbi.2009.04.019}, pmid = {19410582}, issn = {1095-8541}, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Cooperative Behavior ; Family ; *Game Theory ; Group Processes ; Phenotype ; }, abstract = {Group selection theory has a history of controversy. After a period of being in disrepute, models of group selection have regained some ground, but not without a renewed debate over their importance as a theoretical tool. In this paper I offer a simple framework for models of the evolution of altruism and cooperation that allows us to see how and to what extent both a classification with and one without group selection terminology are insightful ways of looking at the same models. Apart from this dualistic view, this paper contains a result that states that inclusive fitness correctly predicts the direction of selection for one class of models, represented by linear public goods games. Equally important is that this result has a flip side: there is a more general, but still very realistic class of models, including models with synergies, for which it is not possible to summarize their predictions on the basis of an evaluation of inclusive fitness.}, } @article {pmid21462403, year = {2009}, author = {Gardner, A and Arce, A and Alpedrinha, J}, title = {Budding dispersal and the sex ratio.}, journal = {Journal of evolutionary biology}, volume = {22}, number = {5}, pages = {1036-1045}, doi = {10.1111/j.1420-9101.2009.01719.x}, pmid = {21462403}, issn = {1420-9101}, support = {//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; *Biological Evolution ; Computer Simulation ; *Demography ; Female ; Male ; *Models, Biological ; Population Dynamics ; *Sex Ratio ; *Social Behavior ; }, abstract = {There is much interest in understanding how population demography impacts upon social evolution. Here, we consider the impact of rate and pattern of dispersal upon a classic social evolutionary trait--the sex ratio. We recover existing analytical results for individual dispersal, and we extend these to allow for budding dispersal. In particular, while a cancelling of relatedness and kin competition effects means that the sex ratio is unaffected by the rate of individual dispersal, we find that a decoupling of relatedness and kin competition means that budding dispersal favours increasingly female-biased sex ratios. More generally, our analysis illustrates the relative ease with which biological problems involving class structure can be solved using a kin selection approach to social evolution theory.}, } @article {pmid19403541, year = {2009}, author = {Milla, R and Forero, DM and Escudero, A and Iriondo, JM}, title = {Growing with siblings: a common ground for cooperation or for fiercer competition among plants?.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1667}, pages = {2531-2540}, pmid = {19403541}, issn = {0962-8452}, mesh = {Demography ; Lupinus/*genetics/*growth & development ; Plant Roots/genetics ; Reproduction ; }, abstract = {Recent work has shown that certain plants can identify their kin in competitive settings through root recognition, and react by decreasing root growth when competing with relatives. Although this may be a necessary step in kin selection, no clear associated improvement in individual or group fitness has been reported to qualify as such. We designed an experiment to address whether genetic relatedness between neighbouring plants affects individual or group fitness in artificial populations. Seeds of Lupinus angustifolius were sown in groups of siblings, groups of different genotypes from the same population and groups of genotypes from different populations. Both plants surrounded by siblings and by genotypes from the same population had lower individual fitness and produced fewer flowers and less vegetative biomass as a group. We conclude that genetic relatedness entails decreased individual and group fitness in L. angustifolius. This, together with earlier work, precludes the generalization that kin recognition may act as a widespread, major microevolutionary mechanism in plants.}, } @article {pmid19392712, year = {2009}, author = {Karban, R and Shiojiri, K}, title = {Self-recognition affects plant communication and defense.}, journal = {Ecology letters}, volume = {12}, number = {6}, pages = {502-506}, doi = {10.1111/j.1461-0248.2009.01313.x}, pmid = {19392712}, issn = {1461-0248}, mesh = {Animals ; Artemisia/genetics/immunology/*physiology ; Autoimmunity ; *Cell Communication ; Grasshoppers ; Immunity ; }, abstract = {Animals have the ability to distinguish self from non-self, which has allowed them to evolve immune systems and, in some instances, to act preferentially towards individuals that are genetically identical or related. Self-recognition is less well known for plants, although recent work indicates that physically connected roots recognize self and reduce competitive interactions. Sagebrush uses volatile cues emitted by clipped branches of self or different neighbours to increase resistance to herbivory. Here, we show that plants that received volatile cues from genetically identical cuttings accumulated less natural damage than plants that received cues from non-self cuttings. Volatile communication is required to coordinate systemic processes such as induced resistance and plants respond more effectively to self than non-self cues. This self/non-self discrimination did not require physical contact and is a necessary first step towards possible kin recognition and kin selection.}, } @article {pmid19367573, year = {2009}, author = {Newson, L}, title = {Cultural versus reproductive success: Why does economic development bring new tradeoffs?.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {21}, number = {4}, pages = {464-471}, doi = {10.1002/ajhb.20925}, pmid = {19367573}, issn = {1520-6300}, mesh = {Anthropology, Cultural ; Biological Evolution ; *Cultural Characteristics ; *Economics ; Family Relations ; Fertility ; Humans ; Marriage ; Reproduction ; Reproductive Behavior/*ethnology ; Social Support ; Socioeconomic Factors ; Sociology ; Women, Working ; }, abstract = {Achievements that attract social rewards in developed countries, such as educational qualifications, a prestigious career, and the ability to acquire prestige goods, interfere with a woman's ability to achieve reproductive success. This tradeoff between cultural and reproductive success may have developed because economic development creates an evolutionarily novel social environment. In the social environment of developed countries, a far smaller proportion of social exchange is between kin than in the small-scale communities in which the human brain and behavior evolved. Evidence suggests that social interaction between non-kin is less likely to encourage behavior that enhances inclusive fitness. A model of the cultural change that is likely to result from this change in social influence suggests that beliefs and values will become increasingly less consistent with the pursuit of fitness (Newson et al. [2007]: Evol Hum Behav 28: 199-210). Responses to the World Value Survey, which has been carried out in over 70 countries, confirm a number of the predictions of this model. In countries where fertility began to decline more recently, people appear to perceive the costs of having children to be lower relative to the cost of childlessness and the benefits of being a parent.}, } @article {pmid19358634, year = {2009}, author = {Ohtsuki, H and Tsuji, K}, title = {Adaptive reproduction schedule as a cause of worker policing in social hymenoptera: a dynamic game analysis.}, journal = {The American naturalist}, volume = {173}, number = {6}, pages = {747-758}, doi = {10.1086/598488}, pmid = {19358634}, issn = {1537-5323}, mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; Female ; Fertility ; *Game Theory ; *Hymenoptera ; Male ; *Models, Biological ; Oviparity ; Population Dynamics ; *Social Behavior ; }, abstract = {Evolutionary theories predict conflicts over sex allocation, male parentage, and reproductive allocation in hymenopteran societies. However, no theory to date has considered the evolution when a colony faces these three conflicts simultaneously. We tackled this issue by developing a dynamic game model, focusing especially on worker policing. Whereas a Nash equilibrium predicts male parentage patterns that are basically the same as those of relatedness-based worker-policing theory (queen multiple mating impedes worker reproduction), we also show the potential for worker policing under queen single mating. Worker policing will depend on the stage of colony growth that is caused by interaction with reproductive allocation conflict or a trade-off between current and future reproduction. Male production at an early stage greatly hinders the growth of the work force and undermines future inclusive fitness of colony members, leading to worker policing at the ergonomic stage. This new mechanism can explain much broader ranges of existing worker-policing behavior than that predicted from relatedness. Predictions differ in many respects from those of models assuming operation of only one or two of the three conflicts, suggesting the importance of interactions among conflicts.}, } @article {pmid19356730, year = {2009}, author = {Sigling, HO and Wolterink-Donselaar, IG and Spruijt, BM}, title = {Home seeking behavior in rat pups: Attachment vs. kin selection, oxytocin vs. vasopressin.}, journal = {European journal of pharmacology}, volume = {612}, number = {1-3}, pages = {48-53}, doi = {10.1016/j.ejphar.2009.03.070}, pmid = {19356730}, issn = {1879-0712}, mesh = {Animals ; Animals, Newborn ; Animals, Outbred Strains ; Behavior, Animal/*drug effects ; Dose-Response Relationship, Drug ; Female ; Injections, Intraventricular ; Models, Animal ; Oxytocin/administration & dosage/*pharmacology ; Pregnancy ; Rats ; Rats, Wistar ; Vasopressins/administration & dosage/antagonists & inhibitors/*pharmacology ; }, abstract = {We are interested in the rat as an animal model for infant-mother attachment. In the first experiment we tried to distinguish between a preference for familiar animals (attachment theory) and a preference for genetically related animals (kin selection theory) with the use of an early cross-fostering procedure. Genetic relationships did not influence preferences in cross-fostered pups on postnatal day 17, only familiarity did. Subsequently we investigated if peptides known to influence affiliative behaviors were also effective in the present paradigm. Injection of oxytocin into the cisterna magna did not yield significant effects on preference, while vasopressin and desglycinamide-[Arg8]vasopressin reduced the preference in a dose dependent manner. The effect of vasopressin was completely blocked by pretreatment with the vasopressin V(1A) receptor antagonist d(CH2)5Tyr(Me)(2),Arg(8)-vasopressin. We discuss the explanatory power of attachment theory and kin selection theory with regard to preference experiments in rats and the usefulness of the rat as an animal model for infant-mother attachment.}, } @article {pmid19350759, year = {2008}, author = {Kemkes, A}, title = {Is perceived childlessness a cue for stereotyping? Evolutionary aspects of a social phenomenon.}, journal = {Biodemography and social biology}, volume = {54}, number = {1}, pages = {33-46}, doi = {10.1080/19485565.2008.9989130}, pmid = {19350759}, issn = {1948-5565}, mesh = {Adolescent ; Adult ; Aged ; *Biological Evolution ; Female ; Health Knowledge, Attitudes, Practice ; Humans ; Logistic Models ; Male ; Middle Aged ; Odds Ratio ; *Parenting ; *Prejudice ; *Reproductive Behavior ; *Social Perception ; *Stereotyping ; Surveys and Questionnaires ; Young Adult ; }, abstract = {The present research investigates the moderating role of the "child factor" in impression formation. 307 university students (148 males, 159 females) were asked to assess 14 traits related to physical attractiveness, resource accruing potential, and emotional stability. The stimulus person was either accompanied by a child or shown individually. As expected, targets depicted with children were believed to be more family-committed and to possess greater parenting skills. The child factor also favourably biased respondents' assessments in terms of honesty, faithfulness, and maturity. Women with children were assumed to be less ambitious, while men with children were believed to be more generous and possess higher status and financial security. All results are discussed within the greater evolutionary context of kin selection and the "good-parent process". It is hypothesized that the negative stereotyping of the voluntary childfree is a by-product of cues that infer prosocial behaviour--similar to those used in mate selection.}, } @article {pmid19335877, year = {2009}, author = {Holzer, B and Keller, L and Chapuisat, M}, title = {Genetic clusters and sex-biased gene flow in a unicolonial Formica ant.}, journal = {BMC evolutionary biology}, volume = {9}, number = {}, pages = {69}, pmid = {19335877}, issn = {1471-2148}, mesh = {Animals ; Ants/*genetics ; Behavior, Animal ; Computational Biology ; DNA, Mitochondrial/genetics ; *Gene Flow ; Genes, Insect ; Genetic Markers ; *Genetics, Population ; Haplotypes ; Male ; Microsatellite Repeats ; Polymorphism, Genetic ; Sequence Analysis, DNA ; Social Behavior ; }, abstract = {BACKGROUND: Animal societies are diverse, ranging from small family-based groups to extraordinarily large social networks in which many unrelated individuals interact. At the extreme of this continuum, some ant species form unicolonial populations in which workers and queens can move among multiple interconnected nests without eliciting aggression. Although unicoloniality has been mostly studied in invasive ants, it also occurs in some native non-invasive species. Unicoloniality is commonly associated with very high queen number, which may result in levels of relatedness among nestmates being so low as to raise the question of the maintenance of altruism by kin selection in such systems. However, the actual relatedness among cooperating individuals critically depends on effective dispersal and the ensuing pattern of genetic structuring. In order to better understand the evolution of unicoloniality in native non-invasive ants, we investigated the fine-scale population genetic structure and gene flow in three unicolonial populations of the wood ant F. paralugubris.

RESULTS: The analysis of geo-referenced microsatellite genotypes and mitochondrial haplotypes revealed the presence of cryptic clusters of genetically-differentiated nests in the three populations of F. paralugubris. Because of this spatial genetic heterogeneity, members of the same clusters were moderately but significantly related. The comparison of nuclear (microsatellite) and mitochondrial differentiation indicated that effective gene flow was male-biased in all populations.

CONCLUSION: The three unicolonial populations exhibited male-biased and mostly local gene flow. The high number of queens per nest, exchanges among neighbouring nests and restricted long-distance gene flow resulted in large clusters of genetically similar nests. The positive relatedness among clustermates suggests that kin selection may still contribute to the maintenance of altruism in unicolonial populations if competition occurs among clusters.}, } @article {pmid19328589, year = {2009}, author = {Helanterä, H and Strassmann, JE and Carrillo, J and Queller, DC}, title = {Unicolonial ants: where do they come from, what are they and where are they going?.}, journal = {Trends in ecology & evolution}, volume = {24}, number = {6}, pages = {341-349}, doi = {10.1016/j.tree.2009.01.013}, pmid = {19328589}, issn = {0169-5347}, mesh = {Animals ; Ants/*genetics/*physiology ; *Behavior, Animal ; *Social Behavior ; }, abstract = {Unicolonial ant populations are the most extensive cooperative units known in nature, forming networks of interconnected nests extending sometimes hundreds of kilometers. Within such a supercolony, worker altruistic behavior might be maladaptive, because it seems to aid random members of the population instead of relatives. However, recent genetic and behavioral data show that, viewed on a sufficiently large scale, unicolonial ants do have colony boundaries that define very large kin groups. It seems likely that they are family groups that continue to express their kin-selected behavior as they grow to extreme sizes. However, at extreme sizes, kin selection theory predicts that these behaviors are maladapted and evolutionarily unstable, a prediction that is supported by their twiggy phylogenetic distribution.}, } @article {pmid19324757, year = {2009}, author = {Wiernasz, DC and Cole, BJ}, title = {Dioecy and the evolution of sex ratios in ants.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1664}, pages = {2125-2132}, pmid = {19324757}, issn = {0962-8452}, mesh = {Animals ; Ants/genetics/*physiology ; Female ; Genetic Variation ; Male ; *Models, Biological ; Population Dynamics ; Sex Characteristics ; *Sex Ratio ; }, abstract = {Split sex ratios, when some colonies produce only male and others only female reproductives, is a common feature of social insects, especially ants. The most widely accepted explanation for split sex ratios was proposed by Boomsma and Grafen, and is driven by conflicts of interest among colonies that vary in relatedness. The predictions of the Boomsma-Grafen model have been confirmed in many cases, but contradicted in several others. We adapt a model for the evolution of dioecy in plants to make predictions about the evolution of split sex ratios in social insects. Reproductive specialization results from the instability of the evolutionarily stable strategy (ESS) sex ratio, and is independent of variation in relatedness. We test predictions of the model with data from a long-term study of harvester ants, and show that it correctly predicts the intermediate sex ratios we observe in our study species. The dioecy model provides a comprehensive framework for sex allocation that is based on the pay-offs to the colony via production of males and females, and is independent of the genetic variation among colonies. However, in populations where the conditions for the Boomsma-Grafen model hold, kin selection will still lead to an association between sex ratio and relatedness.}, } @article {pmid19324749, year = {2009}, author = {Boncoraglio, G and Caprioli, M and Saino, N}, title = {Fine-tuned modulation of competitive behaviour according to kinship in barn swallow nestlings.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1664}, pages = {2117-2123}, pmid = {19324749}, issn = {0962-8452}, mesh = {*Animal Communication ; Animals ; *Competitive Behavior ; Feeding Behavior ; Female ; Linear Models ; Male ; Maternal Behavior ; Paternal Behavior ; Swallows/anatomy & histology/growth & development/*physiology ; }, abstract = {Kin selection theory predicts that, in species where progeny members compete for limiting parental care, individual offspring should be more prone to monopolize parental resources as their genetic relatedness to brood competitors decreases. Mixed parentage among broodmates may arise as a consequence, for example, of extra-pair fertilization or brood parasitism events. In this experimental study of barn swallows (Hirundo rustica), we reciprocally partially cross-fostered hatchlings between broods and compared the behaviour of pairs of related and unrelated broodmates in a competitive context, both under normal food provisioning regime and after mild food deprivation. We found that scramble competition for food mediated by visual and vocal solicitation displays (begging) is inversely related to relatedness among competitors, independent of their level of satiation. Nestlings may modulate their competitive behaviour according to vocal cues that vary with their origin and allow kin recognition. We also uncover direct fitness costs to both parents and offspring arising from mixed parentage in a brood, in terms of increased parental workload and reduced survival of the nestlings. Such previously neglected costs may select for reduced frequency of extra-pair fertilizations and brood parasitism in species with extensive parental care.}, } @article {pmid19324658, year = {2009}, author = {Herbers, JM}, title = {Darwin's 'one special difficulty': celebrating Darwin 200.}, journal = {Biology letters}, volume = {5}, number = {2}, pages = {214-217}, pmid = {19324658}, issn = {1744-9561}, mesh = {Animals ; *Biological Evolution ; Female ; *Insecta ; Male ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Darwin identified eusocial evolution, especially of complex insect societies, as a particular challenge to his theory of natural selection. A century later, Hamilton provided a framework for selection on inclusive fitness. Hamilton's rule is robust and fertile, having generated multiple subdisciplines over the past 45 years. His suggestion that eusociality can be explained via kin selection, however, remains contentious. I review the continuing debate on the role of kin selection in eusocial evolution and suggest some lines of research that should resolve that debate.}, } @article {pmid19324640, year = {2009}, author = {Bressan, P and Zucchi, G}, title = {Human kin recognition is self- rather than family-referential.}, journal = {Biology letters}, volume = {5}, number = {3}, pages = {336-338}, pmid = {19324640}, issn = {1744-9561}, mesh = {Adolescent ; Adult ; Discrimination, Psychological/physiology ; *Face ; *Family ; Female ; Humans ; Male ; Middle Aged ; Pattern Recognition, Visual/*physiology ; Twins, Dizygotic ; Twins, Monozygotic ; Young Adult ; }, abstract = {Inclusive fitness theory predicts that organisms will tend to help close kin more than less related individuals. In a variety of birds and mammals, relatives are recognized by comparing their phenotype to an internal representation or template, which might be learned through either repeated exposure to family members or self-inspection. Mirrors are ubiquitous now, but were absent during our evolutionary history; hence it is hard to predict, and empirically unknown, whether human kin recognition is family- or self-referential. Here we put this issue to the strongest possible test by comparing nepotistic behaviour towards self- versus co-twin-resemblant individuals. Seventy monozygotic and dizygotic twins were shown same-sex faces, covertly manipulated to resemble either themselves or their co-twin, and indicated which individual they would prefer in two prosocial contexts. Self-resemblant faces were significantly preferred to twin-resemblant faces, showing that visual information about the self supersedes that about close family members in the kin-recognition template. Because, under conditions of paternal uncertainty, a reliable family-referent template could be based only on one's mother and maternal relatives, a unique advantage of self-referent phenotype matching is the possibility of (consciously or unconsciously) identifying one's father and paternal relatives as kin.}, } @article {pmid19307041, year = {2009}, author = {Svensson, EI}, title = {Understanding the egalitarian revolution in human social evolution.}, journal = {Trends in ecology & evolution}, volume = {24}, number = {5}, pages = {233-235}, doi = {10.1016/j.tree.2009.01.004}, pmid = {19307041}, issn = {0169-5347}, mesh = {Altruism ; Biological Evolution ; Humans ; Models, Theoretical ; *Social Behavior ; *Social Class ; }, abstract = {Humans are unique among animals in cooperating in large groups of unrelated individuals, with a high degree of resource sharing. These features challenge traditional evolutionary theories built on kin selection or reciprocity. A recent theoretical model by Gavrilets and colleagues takes a fresh look at the 'egalitarian revolution' that separates humans from our closest relatives, the great apes. The model suggests that information from within-group conflicts leads to the emergence of cooperative alliances and social networks.}, } @article {pmid19298495, year = {2009}, author = {Lopez-Vaamonde, C and Raine, NE and Koning, JW and Brown, RM and Pereboom, JJ and Ings, TC and Ramos-Rodriguez, O and Jordan, WC and Bourke, AF}, title = {Lifetime reproductive success and longevity of queens in an annual social insect.}, journal = {Journal of evolutionary biology}, volume = {22}, number = {5}, pages = {983-996}, doi = {10.1111/j.1420-9101.2009.01706.x}, pmid = {19298495}, issn = {1420-9101}, mesh = {Animals ; Bees/*physiology ; England ; Female ; Fertility/physiology ; Genetic Fitness/genetics/*physiology ; *Hierarchy, Social ; Longevity/*physiology ; Male ; }, abstract = {Although central to understanding life-history evolution, the relationship between lifetime reproductive success and longevity remains uncertain in many organisms. In social insects, no studies have reported estimates of queens' lifetime reproductive success and longevity within populations, despite the importance of understanding how sociality and associated within-group conflict affect life-history traits. To address this issue, we studied two samples of colonies of the annual bumblebee, Bombus terrestris audax, reared from wild-caught queens from a single population. In both samples, queens' lifetime reproductive success, measured as either queens' inclusive fitness or as total biomass of queen-produced sexuals (new queens and males), was significantly positively associated with queen longevity, measured from the day the first worker was produced. We suggest that a positive relationship between reproductive success and longevity was inherited from nonsocial ancestors showing parental care and maintained, at least in part, because the presence of workers buffers queens against extrinsic mortality.}, } @article {pmid19298494, year = {2009}, author = {Wild, G and Fernandes, AD}, title = {Investment in the public good through conditional phenotypes of large effect.}, journal = {Journal of evolutionary biology}, volume = {22}, number = {5}, pages = {927-941}, doi = {10.1111/j.1420-9101.2009.01711.x}, pmid = {19298494}, issn = {1420-9101}, mesh = {*Biological Evolution ; Computer Simulation ; *Demography ; Fertility/physiology ; *Genetics, Population ; *Helping Behavior ; Humans ; Models, Biological ; *Population Dynamics ; *Selection, Genetic ; }, abstract = {We investigate the evolution of an individual's willingness to invest in a public good (what we call, helping) in a patch-structured population with limited natal dispersal. We assume that an individual's decision to invest is informed by its dispersal status: an individual makes one decision given it is native to the patch on which it breeds, and is free to make a different decision given that it is not native to the patch on which it breeds. Unlike previous work, we assume that investment in the public good, and the public good, itself, both have a large effect on individual fecundity. Kin selection analysis reveals that only extreme investment decisions (i.e. 'always invest' or 'never invest') can be evolutionarily stable. Numerical results suggest that the evolutionary instability of the 'never invest' phenotype (what we call, complete nonhelping) implies the evolutionary stability of 'always invest' (what we call, complete helping). In addition, numerical results show that bistability of extreme phenotypes is possible, indicating that the adaptive significance of altruism, in this context, is greater than has been previously recognized. Numerical results are supported by computer simulation, and results, themselves, are briefly discussed in a concluding section.}, } @article {pmid19220344, year = {2009}, author = {Baquero, F}, title = {Environmental stress and evolvability in microbial systems.}, journal = {Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases}, volume = {15 Suppl 1}, number = {}, pages = {5-10}, doi = {10.1111/j.1469-0691.2008.02677.x}, pmid = {19220344}, issn = {1469-0691}, mesh = {*Adaptation, Biological ; Bacteria/*genetics ; *Biodiversity ; *Biological Evolution ; *Environment ; }, abstract = {The sustainability of life on the planet depends on the preservation of the existing microbial systems, which constitutes our major "biological atmosphere". The detection of variations in microbial systems as a result of anthropogenic or natural changes is critical both to detect and assess risks and to programme specific interventions. Changes in microbial systems provokes stress, probably altering the local evolutionary time by changing evolvability (the possibilities of microbes to evolve). Methods should be refined to properly assess diversity in microbial systems. We propose that such diversity estimations should be done on a multi-hierarchical scale, encompassing not only organisms, but sub-cellular entities (e.g. chromosomal domains, plasmids, transposons, integrons, genes, gene modules) and supra-cellular organizations (e.g. clones, populations, communities, ecosystems), applying Hamiltonian criteria of inclusive fitness for the different ensembles. In any of these entities, we can generally identify, in a fractal manner, constant and variable parts. Variation in these entities and ensembles is probably both reduced and increased by environmental stress. Because of that, variation in microbial systems might serve as mirrors or symptoms of the health of the planet.}, } @article {pmid19203923, year = {2009}, author = {Monnin, T and Cini, A and Lecat, V and Fédérici, P and Doums, C}, title = {No actual conflict over colony inheritance despite high potential conflict in the social wasp Polistes dominulus.}, journal = {Proceedings. Biological sciences}, volume = {276}, number = {1662}, pages = {1593-1601}, pmid = {19203923}, issn = {0962-8452}, mesh = {Animals ; *Conflict, Psychological ; Female ; Male ; Oviposition ; Population Density ; *Sexual Behavior, Animal ; *Social Behavior ; Wasps/genetics/*physiology ; }, abstract = {Social insect societies are outstanding examples of cooperation and conflict. Individuals work together, yet seek to increase their inclusive fitness at each others' expense. One such conflict is over colony inheritance, when a queen inherits the colony following the death of the previous queen. Colony inheritance is common in the social wasp Polistes dominulus, and it can have dramatic fitness consequences. The subordinate inheriting the colony is often unrelated to the initial foundress (alpha) and the workers, who therefore get zero inclusive fitness. Workers are capable of mating and reproducing, so that inheritance by a subordinate rather than by a related worker is surprising. Using patterns of egg-laying and egg destruction, we show in 32 laboratory colonies that, upon the removal of alpha, workers fully accepted a subordinate as the new breeder. This new alpha monopolized reproduction to the same extent as alpha, and there was no increase in reproduction by workers and other subordinates. Why workers accept a potentially unrelated subordinate as breeder rather than a full-sister worker is unclear. They may be constrained to do so, and they may seek fitness benefits by producing males later in the season or by absconding the nest.}, } @article {pmid19156416, year = {2009}, author = {Lessard, S}, title = {Diffusion approximations for one-locus multi-allele kin selection, mutation and random drift in group-structured populations: a unifying approach to selection models in population genetics.}, journal = {Journal of mathematical biology}, volume = {59}, number = {5}, pages = {659-696}, pmid = {19156416}, issn = {1432-1416}, mesh = {Algorithms ; Alleles ; Animal Migration ; Animals ; Diploidy ; Gene Frequency/genetics ; *Genetic Drift ; Genetics, Population/*methods ; Genotype ; *Inbreeding ; Markov Chains ; *Models, Genetic ; Mutation/*genetics ; Population Density ; *Selection, Genetic ; }, abstract = {Diffusion approximations are ascertained from a two-time-scale argument in the case of a group-structured diploid population with scaled viability parameters depending on the individual genotype and the group type at a single multi-allelic locus under recurrent mutation, and applied to the case of random pairwise interactions within groups. The main step consists in proving global and uniform convergence of the distribution of the group types in an infinite population in the absence of selection and mutation, using a coalescent approach. An inclusive fitness formulation with coefficient of relatedness between a focal individual J affecting the reproductive success of an individual I, defined as the expected fraction of genes in I that are identical by descent to one or more genes in J in a neutral infinite population, given that J is allozygous or autozygous, yields the correct selection drift functions. These are analogous to the selection drift functions obtained with pure viability selection in a population with inbreeding. They give the changes of the allele frequencies in an infinite population without mutation that correspond to the replicator equation with fitness matrix expressed as a linear combination of a symmetric matrix for allozygous individuals and a rank-one matrix for autozygous individuals. In the case of no inbreeding, the mean inclusive fitness is a strict Lyapunov function with respect to this deterministic dynamics. Connections are made between dispersal with exact replacement (proportional dispersal), uniform dispersal, and local extinction and recolonization. The timing of dispersal (before or after selection, before or after mating) is shown to have an effect on group competition and the effective population size.}, } @article {pmid19154382, year = {2009}, author = {Wade, MJ and Brandvain, Y}, title = {Reversing mother's curse: selection on male mitochondrial fitness effects.}, journal = {Evolution; international journal of organic evolution}, volume = {63}, number = {4}, pages = {1084-1089}, pmid = {19154382}, issn = {1558-5646}, support = {1T32HD49336/HD/NICHD NIH HHS/United States ; R01 GM084238/GM/NIGMS NIH HHS/United States ; R01 GM084238-01/GM/NIGMS NIH HHS/United States ; R01GM084238-01/GM/NIGMS NIH HHS/United States ; T32 HD049336/HD/NICHD NIH HHS/United States ; }, mesh = {Alleles ; Animals ; Female ; Humans ; Inbreeding ; Male ; Mitochondria/*genetics ; *Models, Biological ; Reproduction/genetics/*physiology ; Selection, Genetic ; }, abstract = {Many essential organelles and endosymbionts exhibit a strict matrilineal pattern of inheritance. The absence of paternal transmission of such extranuclear components is thought to preclude a response to selection on their effects on male viability and fertility. We overturn this dogma by showing that two mechanisms, inbreeding and kin selection, allow mitochondria to respond to selection on both male viability and fertility. Even modest levels of inbreeding allow such a response to selection when there are direct fitness effects of mitochondria on male fertility because inbreeding associates male fertility traits with mitochondrial matrilines. Male viability effects of mitochondria are also selectable whenever there are indirect fitness effects of males on the fitness of their sisters. When either of these effects is sufficiently strong, we show that there are conditions that allow the spread of mitochondria with direct effects that are harmful to females, contrary to standard expectation. We discuss the implications of our findings for the evolution of organelles and endosymbionts and genomic conflict.}, } @article {pmid19067608, year = {2009}, author = {Wild, G and West, SA}, title = {Genomic imprinting and sex allocation.}, journal = {The American naturalist}, volume = {173}, number = {1}, pages = {E1-14}, doi = {10.1086/593305}, pmid = {19067608}, issn = {1537-5323}, mesh = {Animals ; Competitive Behavior ; Diploidy ; Female ; *Genomic Imprinting ; Haploidy ; Male ; *Models, Biological ; Models, Genetic ; Selection, Genetic ; *Sex Ratio ; Sexual Behavior, Animal ; }, abstract = {Genomic imprinting allows maternally and paternally derived alleles to have different patterns of expression (one allele is often silent). Kin selection provides an explanation of genomic imprinting because conflicts of interest can arise between paternally and maternally inherited alleles when they have different probabilities of being present in other individuals. Our aim here is to examine the extent to which conflicts between paternally and maternally inherited alleles could arise over the allocation of resources to male and female reproduction (sex allocation), for example, conflict over the offspring sex ratio. We examine the situations in which sex allocation is influenced by competitive or cooperative interactions between relatives: local resource competition, local mate competition, and local resource enhancement. We determine solutions for diploids and haplodiploids when either the mother or the offspring controls sex allocation. Our results suggest that the greatest conflict between paternally and maternally inherited alleles and therefore the strongest selection for genomic imprinting will occur in haplodiploid species where the offspring can control sex allocation, such as the social hymenoptera and the polyembryonic parasitoid wasps. Within the social hymenoptera, we expect especially strong selection for genomic imprinting in species subject to local resource competition, such as honeybees and army ants.}, } @article {pmid19018270, year = {2008}, author = {Timmermans, I and Hefetz, A and Fournier, D and Aron, S}, title = {Population genetic structure, worker reproduction and thelytokous parthenogenesis in the desert ant Cataglyphis sabulosa.}, journal = {Heredity}, volume = {101}, number = {6}, pages = {490-498}, doi = {10.1038/hdy.2008.72}, pmid = {19018270}, issn = {1365-2540}, mesh = {Animals ; Ants/*genetics/physiology ; Female ; Male ; Parthenogenesis ; }, abstract = {In social Hymenoptera, within-colony relatedness is usually high due to the haplodiploid sex-determining system. However, factors such as the presence of multiple reproductive queens (polygyny), multiple queen matings (polyandry) or worker reproduction result in decreased relatedness among workers and the brood they rear, and consequently dilute their inclusive fitness benefits from helping. Here, we investigated population genetic structure, mating system, worker reproduction and parthenogenesis in the desert ant Cataglyphis sabulosa. Analysis of worker genotypes showed that colonies are headed by a single queen, mated with 1-5 males. The inbreeding coefficient within colonies and the levels of relatedness between the queens and their mates were positive, indicating that mating occurs between related individuals. Moreover, the mates of a queen are on average related and contribute equally to worker production. Our analyses also indicate that colonies are genetically differentiated and form a population exhibiting no isolation-by-distance pattern, consistent with the independent foundation of new colonies (that is, without the help of workers). Finally, both ovarian dissections and genetic data on the parentage of males show that workers do not reproduce in queenright colonies; however, they lay both haploid (arrhenotokous males) and diploid (thelytokous females) eggs in queenless colonies. In contrast to the congeneric species C. cursor, where new queens are produced by thelytokous parthenogenesis, female sexuals of C. sabulosa result from classical sexual reproduction.}, } @article {pmid19005747, year = {2009}, author = {Vasey, PL and VanderLaan, DP}, title = {Kin selection and the evolution of male androphilia.}, journal = {Archives of sexual behavior}, volume = {38}, number = {2}, pages = {170-171}, doi = {10.1007/s10508-008-9443-9}, pmid = {19005747}, issn = {1573-2800}, mesh = {*Altruism ; Family/*psychology ; Homosexuality, Male/*psychology ; Humans ; Independent State of Samoa ; Male ; United Kingdom ; United States ; }, } @article {pmid18937373, year = {2008}, author = {Aanen, DK and Debets, AJ and de Visser, JA and Hoekstra, RF}, title = {The social evolution of somatic fusion.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {30}, number = {11-12}, pages = {1193-1203}, doi = {10.1002/bies.20840}, pmid = {18937373}, issn = {1521-1878}, mesh = {Animals ; *Biological Evolution ; Crosses, Genetic ; Genetics, Population ; Immune System ; Models, Biological ; Models, Genetic ; Models, Theoretical ; Polymorphism, Genetic ; Reproduction/*genetics/*physiology ; }, abstract = {The widespread potential for somatic fusion among different conspecific multicellular individuals suggests that such fusion is adaptive. However, because recognition of non-kin (allorecognition) usually leads to a rejection response, successful somatic fusion is limited to close kin. This is consistent with kin-selection theory, which predicts that the potential cost of fusion and the potential for somatic parasitism decrease with increasing relatedness. Paradoxically, however, Crozier found that, in the short term, positive-frequency-dependent selection eliminates the required genetic polymorphism at allorecognition loci. The 'Crozier paradox' may be solved if allorecognition is based on extrinsically balanced polymorphisms, for example at immune loci. Alternatively, the assumption of most models that self fusion is mutually beneficial is wrong. If fusion is on average harmful, selection will promote unconditional rejection. However, we propose that fusion within individuals is beneficial, selecting for the ability to fuse, but fusion between individuals on average costly, selecting for non-self recognition (rather than non-kin recognition). We discuss experimental data on fungi that are consistent with this hypothesis.}, } @article {pmid18847475, year = {2008}, author = {Santos, M and Szathmáry, E}, title = {Genetic hitchhiking can promote the initial spread of strong altruism.}, journal = {BMC evolutionary biology}, volume = {8}, number = {}, pages = {281}, pmid = {18847475}, issn = {1471-2148}, mesh = {Alleles ; *Altruism ; *Biological Evolution ; Computer Simulation ; Genetic Variation ; Genetics, Population ; Haplotypes ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {BACKGROUND: The evolutionary origin of strong altruism (where the altruist pays an absolute cost in terms of fitness) towards non-kin has never been satisfactorily explained since no mechanism (except genetic drift) seems to be able to overcome the fitness disadvantage of the individual who practiced altruism in the first place.

RESULTS: Here we consider a multilocus, single-generation random group model and demonstrate that with low, but realistic levels of recombination and social heterosis (selecting for allelic diversity within groups) altruism can evolve without invoking kin selection, because sampling effects in the formation of temporary groups and selection for complementary haplotypes generate nonrandom associations between alleles at polymorphic loci.

CONCLUSION: By letting altruism get off the ground, selection on other genes favourably interferes with the eventual fate of the altruistic trait due to genetic hitchhiking.}, } @article {pmid18837586, year = {2007}, author = {Goetze, D}, title = {Public goods, sharing genes, and the formation of large groups.}, journal = {Politics and the life sciences : the journal of the Association for Politics and the Life Sciences}, volume = {26}, number = {2}, pages = {7-25}, doi = {10.2990/26_2_7}, pmid = {18837586}, issn = {0730-9384}, mesh = {*Altruism ; *Biological Evolution ; Cooperative Behavior ; *Group Processes ; *Heredity ; Humans ; Politics ; Social Behavior ; Social Justice ; }, abstract = {Humans exhibit intense attachments to very large groups, sometimes numbering in the millions. The author addresses the question of how inclinations to attach to large groups might have evolved and identifies the problem of collective action and free riding as the central obstacles to overcome. He argues that the nonsubtractibility feature of public goods and the inclusive fitness theory of W. D. Hamilton are key elements in the evolution of sharing behavior in large groups: a source of group attachments. The argument implies that the mix of goods available and produced in past and present environments impacts the configuration of different-sized groups found in human society.}, } @article {pmid18837585, year = {2007}, author = {Masters, RD}, title = {Historical change and evolutionary theory.}, journal = {Politics and the life sciences : the journal of the Association for Politics and the Life Sciences}, volume = {26}, number = {2}, pages = {46-74}, doi = {10.2990/26_2_46}, pmid = {18837585}, issn = {0730-9384}, mesh = {*Altruism ; *Biological Evolution ; Economics ; Ethnicity ; Game Theory ; *Government ; Humans ; Information Systems ; Jurisprudence ; Leadership ; Politics ; Religion ; Social Behavior ; *Social Change ; Warfare ; }, abstract = {Despite advances in fields like genetics, evolutionary psychology, and human behavior and evolution--which generally focus on individual or small group behavior from a biological perspective--evolutionary biology has made little impact on studies of political change and social history. Theories of natural selection often seem inapplicable to human history because our social behavior is embedded in language (which makes possible the concepts of time and social identity on which what we call "history" depends). Peter Corning's Holistic Darwinism reconceptualizes evolutionary biology, making it possible to go beyond the barriers separating the social and natural sciences. Corning focuses on two primary processes: "synergy" (complex multivariate interactions at multiple levels between a species and its environment) and "cybernetics" (the information systems permitting communication between individuals and groups over time). Combining this frame of reference with inclusive fitness theory, it is possible to answer the most important (and puzzling) question in human history: How did a species that lived for millennia in hunter-gatherer bands form centralized states governing large populations of non-kin (including multi-ethnic empires as well as modern nation-states)? The fragility and contemporary ethnic violence in Kenya and the Congo should suffice as evidence that these issues need to be taken seriously. To explain the rise and fall of states as well as changes in human laws and customs--the core of historical research--it is essential to show how the provision of collective goods can overcome the challenge of self-interest and free-riding in some instances, yet fail to do so in others. To this end, it is now possible to consider how a state providing public goods can--under circumstances that often include effective leadership--contribute to enhanced inclusive fitness of virtually all its members. Because social behavior needs to adapt to ecology, but ecological systems are constantly transformed by human technology and social behavior, multilevel evolutionary processes can explain two central features of human history: the rise, transformations, and ultimate fall of centralized governments (the "stuff" of history); and the biological uniqueness of Homo sapiens as the mammalian species that colonized--and became top carnivore--in virtually every habitable environment on the earth's surface. Once scholars admit the necessity of linking processes of natural selection with human transformations of the natural world, it will seem anomalous that it has taken so long to integrate Darwinian biology and the social sciences.}, } @article {pmid18810630, year = {2010}, author = {Vasey, PL and VanderLaan, DP}, title = {Avuncular tendencies and the evolution of male androphilia in Samoan fa'afafine.}, journal = {Archives of sexual behavior}, volume = {39}, number = {4}, pages = {821-830}, doi = {10.1007/s10508-008-9404-3}, pmid = {18810630}, issn = {1573-2800}, mesh = {Adaptation, Biological ; Adult ; Analysis of Variance ; *Biological Evolution ; Family/*psychology ; Fertility ; Homosexuality, Male/*psychology ; Humans ; Male ; *Models, Biological ; Samoa ; *Social Behavior ; }, abstract = {The kin selection hypothesis for male androphilia holds that genes for male androphilia can be maintained in a population if the fitness costs of not reproducing directly are offset by enhancing indirect fitness. Kin share some proportion of genes identical by virtue of descent. Theoretically speaking, androphilic males can increase their fitness indirectly by allocating altruistic behavior toward kin, which, in turn, allows kin to increase their reproductive success. Research conducted in Independent Samoa has shown that androphilic males (known locally as fa'afafine) report significantly higher avuncular tendencies relative to gynephilic men. Here, we replicate this sexual orientation difference, using a larger, independent sample, suggesting that the documented sexual orientation difference in avuncular tendencies in Independent Samoa is genuine. We also extend previous research by showing that fa'afafine exhibit significantly higher avuncular tendencies even when compared to a more closely matched control group that also lacks direct parental care responsibilities (i.e., gynephilic men with no children). Although the greater avuncular tendencies of fa'afafine relative to gynephilic men are consistent with the predictions of the kin selection hypothesis for male androphilia, further research is needed before deeming male androphilia an adaptation for promoting elevated avuncularity. Likewise, more research is needed before deeming elevated avuncularity in fa'afafine an evolved adaptation for promoting indirect fitness. We discuss these findings in the context of alternative evolutionary explanations for male androphilia (i.e., an evolved by-product of an adaptation).}, } @article {pmid18781278, year = {2008}, author = {Kümmerli, R and Martin, RD}, title = {Patterns of infant handling and relatedness in Barbary macaques (Macaca sylvanus) on Gibraltar.}, journal = {Primates; journal of primatology}, volume = {49}, number = {4}, pages = {271-282}, pmid = {18781278}, issn = {0032-8332}, mesh = {Age Factors ; Analysis of Variance ; Animals ; Female ; Gibraltar ; Macaca/genetics/*physiology ; Male ; *Maternal Behavior ; Microsatellite Repeats/genetics ; Nesting Behavior/*physiology ; *Paternal Behavior ; Sex Factors ; Sexual Behavior, Animal/*physiology ; }, abstract = {Among papionin primates, the Barbary macaque (Macaca sylvanus) shows the most extensive interactions between infants and group members other than the mother. Two different types of interactions occur: (1) long-lasting dyadic interactions between a handler and an infant, and (2) brief triadic interactions between two handlers involving an infant. Previous investigations showed that infant handling by males is best explained as use of infants to manage relationships with other males. In contrast, no adaptive explanation for infant handling by females emerged. Here, we compared the infant-handling pattern between subadult/adult males and subadult/adult females in a free-ranging group of 46 Barbary macaques on Gibraltar to test whether the relationship management hypothesis also applies to female handlers. We further investigated the infant-handling pattern of juveniles and used microsatellite markers to estimate relatedness between infant handlers and the infant's mother. We found that males, females and juveniles all participated extensively in triadic interactions using infants of above-average related females. In contrast, only males and juveniles were highly involved in dyadic interactions with infants of related females, while females rarely handled infants other than their own. The pattern of infant handling was entirely compatible with the predictions of the relationship management hypothesis for males and mostly so for females. Moreover, our genetic analysis revealed that males and females differ in their partner choice: while females preferred to interact with related females, males had no significant preference to interact with related males. We further discuss the observed above-average relatedness values between infant handlers and the infant's mother in the light of kin-selection theory.}, } @article {pmid18761362, year = {2009}, author = {Platek, SM and Krill, AL and Wilson, B}, title = {Implicit trustworthiness ratings of self-resembling faces activate brain centers involved in reward.}, journal = {Neuropsychologia}, volume = {47}, number = {1}, pages = {289-293}, doi = {10.1016/j.neuropsychologia.2008.07.018}, pmid = {18761362}, issn = {0028-3932}, mesh = {Brain/*physiology ; *Brain Mapping ; Esthetics ; *Face ; Facial Expression ; Female ; Functional Laterality ; Humans ; Image Processing, Computer-Assisted ; Magnetic Resonance Imaging ; Male ; Oxygen/blood ; Pattern Recognition, Visual/physiology ; Photic Stimulation/methods ; *Reward ; Self Concept ; Sex Factors ; }, abstract = {On the basis of Hamilton's (Hamilton, W. D. (1964). The genetical evolution of social behavior I, II. Journal of Theoretical Biology, 7, 17-52) theory of inclusive fitness, self-facial resemblance is hypothesized as a mechanism for self-referent phenotypic matching by which humans can detect kin. To understand the mechanisms underlying pro-sociality toward self-resembling faces, we investigated the neural correlates of implicit trustworthiness ratings for self-resembling faces. Here we show that idiosyncratic trustworthiness ratings of self-resembling faces predict brain activation in the ventral inferior, middle and medial frontal gyri, substrates involved in reward processing. These findings demonstrate that neural reward centers are implicated in evaluating implicit pro-social behaviors toward self-resembling faces. These findings suggest that humans have evolved to use neurocomputational architecture dedicated to face processing and reward evaluation for the differentiation of kin, which drives implicit idiosyncratic affectively regulated social interactions.}, } @article {pmid18707497, year = {2002}, author = {Hudson, RE and Aukema, JE and Rispe, C and Roze, D}, title = {Altruism, cheating, and anticheater adaptations in cellular slime molds.}, journal = {The American naturalist}, volume = {160}, number = {1}, pages = {31-43}, doi = {10.1086/340613}, pmid = {18707497}, issn = {1537-5323}, abstract = {Cellular slime molds (CSMs) possess a remarkable life cycle that encompasses an extreme act of altruism. CSM cells live as individual amoebae until starved, then aggregate and ultimately transform themselves into a multicellular fruiting body. This fruiting body consists of stalk cells (altruists that eventually die) and spores (the beneficiaries of this sacrifice). Altruistic systems such as this are vulnerable to cheaters, which are individuals unrelated to the altruists that obtain the benefits provided by them without reciprocating. Here, we investigate two forces that can maintain CSM altruism despite cheating: kin selection and anticheater adaptations. First, we present new kinship-based models based on CSM developmental biology to evaluate the efficacy of kin selection. These models show that stalk-making genotypes can still be maintained when aggregations are initiated by multiple "founder" spores, provided that spores of stalkless fruiting bodies have low rates of dispersal and dispersal success is a concave function of stalk height. Second, we review proposals that several features of CSM development, such as the chemical suppression of the redifferentiation of prestalk cells into prespores, act as anticheater adaptations.}, } @article {pmid18707485, year = {2002}, author = {MacColl, AD and Hatchwell, BJ}, title = {Temporal variation in fitness payoffs promotes cooperative breeding in long-tailed tits Aegithalos caudatus.}, journal = {The American naturalist}, volume = {160}, number = {2}, pages = {186-194}, doi = {10.1086/341013}, pmid = {18707485}, issn = {1537-5323}, abstract = {Cooperative breeding is paradoxical because some individuals forego independent reproduction and instead help others to reproduce. The ecological constraints model states that such behavior arises because of constraints on independent reproduction. Spatial variation in constraints has been shown to co-vary with the incidence of cooperative breeding in correlational and experimental studies. Here, we examine whether temporally variable ecological constraints can act in a similar way to promote cooperative breeding in the atypical system of long-tailed tits Aegithalos caudatus. In this species, individuals may switch reproductive tactics from breeding to helping within the same breeding season. Using 7 yr of field data, we show that reproductive success declined seasonally because of declines in brood size, nestling weight, and juvenile survival. The survival to breeding age of chicks from nests with helpers was higher than for chicks from nests without helpers, and since helpers usually helped at the nest of a close relative, they accrued inclusive fitness benefits. We used these data to model the expected fitness payoffs of breeding and helping at different times during the season. The model shows that late in the breeding season, the fitness payoff from a kin-directed helping tactic becomes greater than that from independent breeding. The behavioral switch predicted by the model is consistent with the observed switch from breeding to helping, which shows that cooperative breeding may evolve as a way of making the best of a bad job at the end of a temporally constrained breeding season.}, } @article {pmid18707355, year = {2001}, author = {Foster, KR and Ratnieks, FL}, title = {The effect of sex-allocation biasing on the evolution of worker policing in hymenopteran societies.}, journal = {The American naturalist}, volume = {158}, number = {6}, pages = {615-623}, doi = {10.1086/323588}, pmid = {18707355}, issn = {1537-5323}, abstract = {Mutual policing is thought to be important in conflict suppression at all levels of biological organization. In hymenopteran societies (bees, ants, and wasps), multiple mating by queens favors mutual policing of male production among workers (worker policing). However, worker policing of male production is proving to be more widespread than predicted by relatedness patterns, occurring in societies headed by single-mated queens in which, paradoxically, workers are more related to the workers' sons that they kill than the queen's sons that they spare. Here we develop an inclusive-fitness model to show that a second reproductive conflict, the conflict over sex allocation, can explain the evolution of worker policing contrary to relatedness predictions. Among ants, and probably other social Hymenoptera, workers kill males to favor their more related sisters. Importantly, males are killed at the larval stage, presumably because workers cannot determine the sex of queen-laid eggs. Sex-allocation biasing favors worker policing because policing removes some males (the workers' sons) at low cost at the egg stage rather than at higher cost at the larval stage. Our model reveals an important interaction between two reproductive conflicts in which the presence of one conflict (sex allocation) favors the suppression of the other (male production by workers).}, } @article {pmid18707354, year = {2001}, author = {Andersson, M}, title = {Relatedness and the evolution of conspecific brood parasitism.}, journal = {The American naturalist}, volume = {158}, number = {6}, pages = {599-614}, doi = {10.1086/324113}, pmid = {18707354}, issn = {1537-5323}, abstract = {In conspecific brood parasitism (CBP), a parasitic female takes advantage of the parental care performed by a host female by laying eggs in the nest of the host. The host female raises the offspring of the parasitic female as well as her own. In species where local females are related, direct costs for the host might be more than compensated for by gains in inclusive fitness through increased reproduction of a related parasite, but the role of relatedness in CBP is debated. This inclusive-fitness model of parasitism, structured as a game between host and parasite, suggests that both females can gain inclusive fitness and that host-parasite relatedness can therefore facilitate the evolution of CBP. Crucial assumptions are that there is kin discrimination and a potential for host resistance to parasitism by unrelated females but close relatives are accepted. The cost of parasitism in terms of reduced clutch size or offspring survival for the host must not be large; otherwise, parasitism will reduce her inclusive fitness. Therefore, if these costs are high, it does not benefit a host to accept a parasite, even if the parasite is closely related. The secondary female may still have higher fitness from parasitism, but if the costs are high, she should parasitize an unrelated host, not a relative. This requires that the reduction in parasite success that a host can cause by resistance is not too large; otherwise, it will be better for the secondary female to parasitize an accepting related host or to nest solitarily. For these reasons, host-parasite relatedness is most likely to occur in animals where costs of being parasitized are low and host resistance can markedly reduce the success of an unrelated parasite. When costs are higher, parasitism of unrelated hosts may be better, and if host resistance strongly reduces parasite success, solitary breeding is preferable. In some cases, CBP is directly advantageous for the host, and it may sometimes evolve in close connection with cooperative breeding, which is also considered in the model. Some but not all empirical results support these ideas, and more detailed studies of behavior, relatedness, and reproduction of host and parasite are needed for critical tests.}, } @article {pmid18707345, year = {2001}, author = {Reuter, M and Keller, L}, title = {Sex ratio conflict and worker production in eusocial hymenoptera.}, journal = {The American naturalist}, volume = {158}, number = {2}, pages = {166-177}, doi = {10.1086/321311}, pmid = {18707345}, issn = {1537-5323}, abstract = {The best known of the conflicts occurring in eusocial Hymenoptera is queen-worker conflict over sex ratio. So far, sex ratio theory has mostly focused on optimal investment in the production of male versus female sexuals, neglecting the investment in workers. Increased investment in workers decreases immediate sexual productivity but increases expected future colony productivity. Thus, an important issue is to determine the queen's and workers' optimal investment in each of the three castes (workers, female sexuals, and male sexuals), taking into account a possible trade-off between production of female sexuals and workers (both castes developing from diploid female eggs). Here, we construct a simple and general kin selection model that allows us to calculate the evolutionarily stable investments in the three castes, while varying the identity of the party controlling resource allocation (relative investment in workers, female sexuals, and male sexuals). Our model shows that queens and workers favor the investment in workers that maximizes lifetime colony productivity of sexual males and females, whatever the colony kin structure. However, worker production is predicted to be at this optimum only if one of the two parties has complete control over resource allocation, a situation that is evolutionarily unstable because it strongly selects the other party to manipulate sex allocation in its favor. Queens are selected to force workers to raise all the males by limiting the number of eggs they lay, whereas workers should respond to egg limitation by raising a greater proportion of the female eggs into sexual females rather than workers as a means to attain a more female-biased sex allocation. This tug-of-war between queens and workers leads to a stable equilibrium where sex allocation is between the queen and worker optima and the investment in workers is below both parties' optimum. Our model further shows that, under most conditions, female larvae are in strong conflict with queens and workers over their developmental fate because they value their own reproduction more than that of siblings. With the help of our model, we also investigate how variation in queen number and number of matings per queen affect the level of conflict between queens, workers, and larvae and ultimately the allocation of resource in the three castes. Finally, we make predictions that allow us to test which party is in control of sex allocation and caste determination.}, } @article {pmid18691258, year = {2008}, author = {Johnstone, RA}, title = {Kin selection, local competition, and reproductive skew.}, journal = {Evolution; international journal of organic evolution}, volume = {62}, number = {10}, pages = {2592-2599}, doi = {10.1111/j.1558-5646.2008.00480.x}, pmid = {18691258}, issn = {0014-3820}, mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; Competitive Behavior ; *Models, Theoretical ; Population Density ; Population Dynamics ; Reproduction ; *Social Behavior ; }, abstract = {In a spatially structured population, limited dispersal gives rise to local relatedness, potentially favoring indiscriminate helping behavior. However, it also leads to local competition, which reduces the benefits of helping local kin. This tension has become the focus for a growing body of theoretical work. Existing models, however, have focused chiefly on the net impact of limited dispersal on cooperative or competitive effort in a homogeneous population. Here, I extend existing models of kin selection in a group-structured population to allow for asymmetries in expected fecundity and reproductive success among group members. I explore the consequent impact of limited dispersal on the evolution of helping and harming behavior, and on the degree of reproductive inequality or skew. I show that when individuals in a group differ in their expected fecundity, limited dispersal gives rise to kin selection for harming behavior on the part of more fecund individuals, and for helping behavior on the part of less fecund individuals. As a result, philopatry tends to exaggerate differences in reproductive success, and so promotes greater reproductive skew.}, } @article {pmid18658236, year = {2008}, author = {Schneider, JM and Bilde, T}, title = {Benefits of cooperation with genetic kin in a subsocial spider.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {105}, number = {31}, pages = {10843-10846}, pmid = {18658236}, issn = {1091-6490}, mesh = {Animals ; Behavior, Animal/*physiology ; Biological Evolution ; *Cooperative Behavior ; Feeding Behavior/*physiology ; Female ; Greece ; Linear Models ; Spiders/genetics/*physiology ; }, abstract = {Interaction within groups exploiting a common resource may be prone to cheating by selfish actions that result in disadvantages for all members of the group, including the selfish individuals. Kin selection is one mechanism by which such dilemmas can be resolved. This is because selfish acts toward relatives include the cost of lowering indirect fitness benefits that could otherwise be achieved through the propagation of shared genes. Kin selection theory has been proved to be of general importance for the origin of cooperative behaviors, but other driving forces, such as direct fitness benefits, can also promote helping behavior in many cooperatively breeding taxa. Investigating transitional systems is therefore particularly suitable for understanding the influence of kin selection on the initial spread of cooperative behaviors. Here we investigated the role of kinship in cooperative feeding. We used a cross-fostering design to control for genetic relatedness and group membership. Our study animal was the periodic social spider Stegodyphus lineatus, a transitional species that belongs to a genus containing both permanent social and periodic social species. In S. lineatus, the young cooperate in prey capture and feed communally. We provide clear experimental evidence for net benefits of cooperating with kin. Genetic relatedness within groups and not association with familiar individuals directly improved feeding efficiency and growth rates, demonstrating a positive effect of kin cooperation. Hence, in communally feeding spiders, nepotism favors group retention and reduces the conflict between selfish interests and the interests of the group.}, } @article {pmid18656491, year = {2008}, author = {Dickson, ES}, title = {Expected utility violations evolve under status-based selection mechanisms.}, journal = {Journal of theoretical biology}, volume = {254}, number = {3}, pages = {650-654}, doi = {10.1016/j.jtbi.2008.06.033}, pmid = {18656491}, issn = {1095-8541}, mesh = {*Choice Behavior ; *Decision Making ; Game Theory ; Humans ; Models, Genetic ; Models, Psychological ; *Selection, Genetic ; Social Environment ; }, abstract = {The expected utility theory of decision making under uncertainty, a cornerstone of modern economics, assumes that humans linearly weight "utilities" for different possible outcomes by the probabilities with which these outcomes occur. Despite the theory's intuitive appeal, both from normative and from evolutionary perspectives, many experiments demonstrate systematic, though poorly understood, patterns of deviation from EU predictions. This paper offers a novel theoretical account of such patterns of deviation by demonstrating that EU violations can emerge from evolutionary selection when individual "status" affects inclusive fitness. In humans, battles for resources and social standing involve high-stakes decision making, and assortative mating ensures that status matters for fitness outcomes. The paper therefore proposes grounding the study of decision making under uncertainty in an evolutionary game-theoretic framework.}, } @article {pmid18625292, year = {2008}, author = {Rachlin, H and Jones, BA}, title = {Altruism among relatives and non-relatives.}, journal = {Behavioural processes}, volume = {79}, number = {2}, pages = {120-123}, pmid = {18625292}, issn = {0376-6357}, support = {R01 MH044049/MH/NIMH NIH HHS/United States ; R01 MH044049-19/MH/NIMH NIH HHS/United States ; R01MH04404916/MH/NIMH NIH HHS/United States ; }, mesh = {Adult ; *Altruism ; *Choice Behavior ; *Cooperative Behavior ; Family ; Group Structure ; Humans ; Models, Biological ; *Psychological Distance ; Selection, Genetic ; }, abstract = {Hamilton's [Hamilton, W.D., 1964. The genetical evolution of social behavior, I, II. J. Theor. Biol. 7, 1-52] kin-selection theory predicts that altruism will be greater with greater genetic overlap (degree of kinship) between giver and receiver. Kin may be identified in terms of social distance-the closer you feel to someone else, (a) the greater your genetic overlap with them should be, and (b) the more altruistic you should be toward them. The present experiment determined the amount of their own (hypothetical) monetary reward undergraduates were willing to forgo in order to give $75 to other people at various social distances. We found that (a) genetic relationship and (b) altruism varied inversely with social distance; the closer you feel to someone else, the closer their relation to you is likely to be, and the more altruistic you are likely to be toward them. However, even at the same social distance, participants were willing to forgo significantly more money for the benefit of relatives than for the benefit of non-relatives. These results are consistent with kin-selection theory and imply that altruism is determined by factors in addition to social distance.}, } @article {pmid18624886, year = {2008}, author = {Wild, G}, title = {Toward evolutionary graphs with two sexes: a kin selection analysis of a sex allocation problem.}, journal = {Journal of evolutionary biology}, volume = {21}, number = {5}, pages = {1428-1437}, doi = {10.1111/j.1420-9101.2008.01561.x}, pmid = {18624886}, issn = {1420-9101}, mesh = {*Biological Evolution ; *Game Theory ; *Models, Genetic ; Mutation ; Population Dynamics ; *Selection, Genetic ; *Sex Ratio ; }, abstract = {Evolutionary graphs are used to model the effects of spatial and social structure in social evolutionary problems (e.g. evolutionary games). Recent work has highlighted the fact that evolution on graphs can be understood using kin selection theory. This paper shows how one can use kin selection to study evolutionary graphs inhabited by a diploid sexual organism by means of a simple example. Specifically, we study the well-known sex allocation problem of how best to divide a fixed amount of effort between the production of sons on the one hand and the production of daughters on the other. Like many previous studies, we identify equal investment in sons and daughters as the only phenotype favoured by selection. Our analysis also highlights the advantages and disadvantages of applying kin selection to the study of evolutionary graphs.}, } @article {pmid18624737, year = {2008}, author = {Schausberger, P and Hoffmann, D}, title = {Maternal manipulation of hatching asynchrony limits sibling cannibalism in the predatory mite Phytoseiulus persimilis.}, journal = {The Journal of animal ecology}, volume = {77}, number = {6}, pages = {1109-1114}, doi = {10.1111/j.1365-2656.2008.01440.x}, pmid = {18624737}, issn = {1365-2656}, mesh = {Animals ; Behavior, Animal ; *Cannibalism ; Female ; Mites/*physiology ; Oviposition ; Reproduction/physiology ; Time Factors ; }, abstract = {1. Sibling cannibalism is a common phenomenon in the animal kingdom but entails a high risk of direct and inclusive fitness loss for the mother and her offspring. Therefore, mechanisms limiting sibling cannibalism are expected to be selected for. One way of maternal manipulation of sibling cannibalism is to influence hatching asynchrony between nearby laid eggs. This has rarely been tested experimentally. 2. We examined the ability of ovipositing females of the cannibalistic predatory mite Phytoseiulus persimilis to influence the occurrence of sibling cannibalism among offspring by manipulating hatching asynchrony of nearby laid eggs. 3. In the first experiment, we assessed the occurrence of sibling cannibalism in relation to the hatching interval (24 h and 48 h) between nearby laid eggs. In the second experiment, we tested whether ovipositing females discriminate sites containing young (24-h old) and old (48-h old) eggs, fresh and old traces (metabolic waste products and possibly pheromones) left by the same female (24 h and 48 h ago), or young eggs plus fresh female traces and old eggs plus old female traces. Both experiments were conducted with and without prey. 4. Without prey, siblings were more likely to cannibalize each other if the hatching interval between nearby laid eggs was short (24 h). Cannibalism occurred less often when senior siblings (protonymphs) experienced a delay in the opportunity to cannibalize junior siblings (larvae). 5. Independent of prey availability, females preferentially added new eggs to sites containing old eggs plus old female traces but did neither distinguish between young and old eggs presented without own traces nor between fresh and old traces presented without eggs. 6. We discuss cue perception and use by P. persimilis females and contrast the outcome of our experiments and theoretical predictions of sibling cannibalism. We conclude that P. persimilis mothers increase hatching asynchrony of nearby laid eggs to prevent sibling cannibalism on the last produced offspring. Such a behaviour may be considered a simple form of maternal care increasing the survival prospects of offspring.}, } @article {pmid18622630, year = {2008}, author = {Holzer, B and Chapuisat, M and Keller, L}, title = {Foreign ant queens are accepted but produce fewer offspring.}, journal = {Oecologia}, volume = {157}, number = {4}, pages = {717-723}, pmid = {18622630}, issn = {0029-8549}, mesh = {Animals ; Ants/genetics/*physiology ; *Competitive Behavior ; Female ; Genetics, Population ; Reproduction/physiology ; *Sexual Behavior, Animal ; *Social Dominance ; }, abstract = {Understanding social evolution requires us to understand the processes regulating the number of breeders within social groups and how they partition reproduction. Queens in polygynous (multiple queens per colony) ants often seek adoption in established colonies instead of founding a new colony independently. This mode of dispersal leads to potential conflicts, as kin selection theory predicts that resident workers should favour nestmate queens over foreign queens. Here we compared the survival of foreign and resident queens as well as their relative reproductive share. We used the ant Formica exsecta to construct colonies consisting of one queen with workers related to this resident queen and introduced a foreign queen. We found that the survival of foreign queens did not differ from that of resident queens over a period of 136 days. However, the genetic analyses revealed that resident queens produced a 1.5-fold higher number of offspring than introduced queens, and had an equal or higher share in 80% of the colonies. These data indicate that some discrimination can occur against dispersing individuals and that dispersal can thus have costs in terms of direct reproduction for dispersing queens.}, } @article {pmid18621061, year = {2008}, author = {Kronauer, DJ}, title = {Genomic imprinting and kinship in the social Hymenoptera: what are the predictions?.}, journal = {Journal of theoretical biology}, volume = {254}, number = {4}, pages = {737-740}, doi = {10.1016/j.jtbi.2008.06.019}, pmid = {18621061}, issn = {1095-8541}, mesh = {Alleles ; Animals ; Diploidy ; Female ; Gene Expression ; *Genomic Imprinting ; Haploidy ; Hymenoptera/*genetics/physiology ; Male ; *Models, Genetic ; *Social Behavior ; }, abstract = {The kinship theory of genomic imprinting predicts that conflicts of interest between parents can promote the evolution of opposed expression patterns of maternally and paternally derived alleles in the offspring. The social Hymenoptera (ants, some bees, and some wasps) are particularly suitable to test this theory, because a variety of social conflicts are predicted due to relatedness asymmetries between female and male nestmates that are a corollary of haplo-diploid sex determination. Here I argue that the kin-selection predictions for genomic imprinting in social Hymenoptera might in many cases be more complex than previously suggested, because the optimal strategy will have to take fitness effects in different castes and sexes into account.}, } @article {pmid18565030, year = {2008}, author = {Chaves-Campos, J and DeWoody, JA}, title = {The spatial distribution of avian relatives: do obligate army-ant-following birds roost and feed near family members?.}, journal = {Molecular ecology}, volume = {17}, number = {12}, pages = {2963-2974}, doi = {10.1111/j.1365-294X.2008.03811.x}, pmid = {18565030}, issn = {1365-294X}, mesh = {Animals ; Behavior, Animal/*physiology ; Biodiversity ; Costa Rica ; Feeding Behavior/physiology ; Female ; Genetic Speciation ; Geography ; Male ; Microsatellite Repeats/*genetics ; Passeriformes/classification/*genetics/physiology ; }, abstract = {The ocellated antbird (Phaenostictus mcleannani) feeds in groups and therefore is an informative species in which to study the biological factors that modulate avian group living. These birds congregate at swarms of army ants to capture fleeing prey, and previous observations suggest that males may be philopatric, feed with close relatives, and defend communal feeding ranges. We assessed whether kin selection could be an important factor maintaining group formation in a population of ocellated antbirds inhabiting continuous forest at La Selva Biological Station, Costa Rica, using radiotelemetry and 15 novel microsatellite markers. We predicted that the roosting areas of closely related adult males should overlap and that adult males feeding simultaneously at the same swarm should be highly related. We banded and genotyped 65 individuals (>or= 88% of the population) and radiotagged 30 of them. The results generally did not conform to our predictions. Little overlap occurred among the roosting areas of same-sex individuals, and nearest roosting neighbours (either same or opposite sex) were generally unrelated. A small proportion of male dyads suggested short-distance dispersal, but in general the distribution of genotypes within the study area approached randomness. We found little evidence of natal philopatry in either sex. Less than half of the feeding groups sampled included highly related males; most consisted of unrelated individuals. Hence, we found limited potential for kin selection to favour group living and suggest that other factors, particularly direct benefits (e.g. food intake), are probably more important than indirect effects (nepotism).}, } @article {pmid18522914, year = {2008}, author = {Sharp, SP and Simeoni, M and Hatchwell, BJ}, title = {Dispersal of sibling coalitions promotes helping among immigrants in a cooperatively breeding bird.}, journal = {Proceedings. Biological sciences}, volume = {275}, number = {1647}, pages = {2125-2130}, pmid = {18522914}, issn = {0962-8452}, mesh = {Animal Communication ; Animal Migration ; Animals ; *Breeding ; *Cooperative Behavior ; Female ; Male ; *Nesting Behavior ; Passeriformes/genetics/*physiology ; Population Dynamics ; Sexual Behavior, Animal ; }, abstract = {Kin selection is a major force in social evolution, but dispersal is often assumed to reduce its impact by diluting kinship. In most cooperatively breeding vertebrates, in which more than two individuals care for young, juveniles delay dispersal and become helpers in family groups. In long-tailed tits (Aegithalos caudatus), however, offspring disperse to breed and helpers are failed breeders that preferentially aid kin. Helping also occurs among immigrants, but their origins are unknown and cooperation in these cases is poorly understood. Here, we combine long-term demographic and genetic data from our study population to investigate immigration and helping in this species. We first used a novel application of parentage analysis to discriminate between immigrants and unknown philopatric recruits. We then cross-checked sibship reconstruction with pairwise relatedness estimates to show that immigrants disperse in sibling coalitions and helping among them is kin biased. These results indicate that dispersal need not preclude sociality, and dispersal of kin coalitions may help maintain kin-selected cooperation in the absence of delayed dispersal.}, } @article {pmid18522913, year = {2008}, author = {Wolf, JB and Trillmich, F}, title = {Kin in space: social viscosity in a spatially and genetically substructured network.}, journal = {Proceedings. Biological sciences}, volume = {275}, number = {1647}, pages = {2063-2069}, pmid = {18522913}, issn = {0962-8452}, mesh = {Animals ; *Behavior, Animal ; Female ; Population Density ; Population Dynamics ; Sea Lions/genetics/*physiology ; *Social Behavior ; }, abstract = {Population substructuring is a fundamental aspect of animal societies. A growing number of theoretical studies recognize that who-meets-whom is not random, but rather determined by spatial relationships or illustrated by social networks. Structural properties of large highly dynamic social systems are notoriously difficult to unravel. Network approaches provide powerful ways to analyse the intricate relationships between social behaviour, dispersal strategies and genetic structure. Applying network analytical tools to a colony of the highly gregarious Galápagos sea lion (Zalophus wollebaeki), we find several genetic clusters that correspond to spatially determined 'network communities'. Overall relatedness was low, and genetic structure in the network can be interpreted as an emergent property of philopatry and seems not to be primarily driven by targeted interactions among highly related individuals in family groups. Nevertheless, social relationships between directly adjacent individuals in the network were stronger among genetically more similar individuals. Taken together, these results suggest that even small differences in the degree of relatedness can influence behavioural decisions. This raises the fascinating prospect that kin selection may also apply to low levels of relatedness within densely packed animal groups where less obvious co-operative interactions such as increased tolerance and stress reduction are important.}, } @article {pmid18511689, year = {2008}, author = {Hughes, WO and Oldroyd, BP and Beekman, M and Ratnieks, FL}, title = {Ancestral monogamy shows kin selection is key to the evolution of eusociality.}, journal = {Science (New York, N.Y.)}, volume = {320}, number = {5880}, pages = {1213-1216}, doi = {10.1126/science.1156108}, pmid = {18511689}, issn = {1095-9203}, mesh = {Altruism ; Animals ; Ants ; Bees ; *Biological Evolution ; Female ; Male ; Phylogeny ; *Sexual Behavior, Animal ; *Social Behavior ; Sociobiology ; Wasps ; }, abstract = {Close relatedness has long been considered crucial to the evolution of eusociality. However, it has recently been suggested that close relatedness may be a consequence, rather than a cause, of eusociality. We tested this idea with a comparative analysis of female mating frequencies in 267 species of eusocial bees, wasps, and ants. We found that mating with a single male, which maximizes relatedness, is ancestral for all eight independent eusocial lineages that we investigated. Mating with multiple males is always derived. Furthermore, we found that high polyandry (>2 effective mates) occurs only in lineages whose workers have lost reproductive totipotency. These results provide the first evidence that monogamy was critical in the evolution of eusociality, strongly supporting the prediction of inclusive fitness theory.}, } @article {pmid18505710, year = {2008}, author = {Young, LC and Zaun, BJ and Vanderwerf, EA}, title = {Successful same-sex pairing in Laysan albatross.}, journal = {Biology letters}, volume = {4}, number = {4}, pages = {323-325}, pmid = {18505710}, issn = {1744-9561}, mesh = {Animals ; Birds/genetics/*physiology ; Cooperative Behavior ; Female ; Male ; *Nesting Behavior ; Pair Bond ; Population Density ; Population Dynamics ; Sex Determination Processes ; Sex Ratio ; *Social Behavior ; }, abstract = {Unrelated same-sex individuals pairing together and cooperating to raise offspring over many years is a rare occurrence in the animal kingdom. Cooperative breeding, in which animals help raise offspring that are not their own, is often attributed to kin selection when individuals are related, or altruism when individuals are unrelated. Here we document long-term pairing of unrelated female Laysan albatross (Phoebastria immutabilis) and show how cooperation may have arisen as a result of a skewed sex ratio in this species. Thirty-one per cent of Laysan albatross pairs on Oahu were female-female, and the overall sex ratio was 59% females as a result of female-biased immigration. Female-female pairs fledged fewer offspring than male-female pairs, but this was a better alternative than not breeding. In most female-female pairs that raised a chick in more than 1 year, at least one offspring was genetically related to each female, indicating that both females had opportunities to reproduce. These results demonstrate how changes in the sex ratio of a population can shift the social structure and cause cooperative behaviour to arise in a monogamous species, and they also underscore the importance of genetically sexing monomorphic species.}, } @article {pmid18449959, year = {2008}, author = {MacLean, RC}, title = {The tragedy of the commons in microbial populations: insights from theoretical, comparative and experimental studies.}, journal = {Heredity}, volume = {100}, number = {5}, pages = {471-477}, pmid = {18449959}, issn = {1365-2540}, mesh = {*Biological Evolution ; *Microbiology ; *Models, Theoretical ; Thermodynamics ; }, abstract = {First principles of thermodynamics imply that metabolic pathways are faced with a trade-off between the rate and yield of ATP production. Simple evolutionary models argue that this trade-off generates a fundamental social conflict in microbial populations: average fitness in a population is highest if all individuals exploit common resources efficiently, but individual reproductive rate is maximized by consuming common resources at the highest possible rate, a scenario known as the tragedy of the commons. In this paper, I review studies that have addressed two key questions: What is the evidence that the rate-yield trade-off is an evolutionary constraint on metabolic pathways? And, if so, what determines evolutionary outcome of the conflicts generated by this trade-off? Comparative studies and microbial experiments provide evidence that the rate-yield trade-off is an evolutionary constraint that is driven by thermodynamic constraints that are common to all metabolic pathways and pathway-specific constraints that reflect the evolutionary history of populations. Microbial selection experiments show that the evolutionary consequences of this trade-off depend on both kin selection and biochemical constraints. In well-mixed populations with low relatedness, genotypes with rapid and efficient metabolism can coexist as a result of negative frequency-dependent selection generated by density-dependent biochemical costs of rapid metabolism. Kin selection can promote the maintenance of efficient metabolism in structured populations with high relatedness by ensuring that genotypes with efficient metabolic pathways gain an indirect fitness benefit from their competitive restraint. I conclude by suggesting avenues for future research and by discussing the broader implications of this work for microbial social evolution.}, } @article {pmid18446375, year = {2008}, author = {Fauvergue, X and Lo Genco, A and Lo Pinto, M}, title = {Virgins in the wild: mating status affects the behavior of a parasitoid foraging in the field.}, journal = {Oecologia}, volume = {156}, number = {4}, pages = {913-920}, pmid = {18446375}, issn = {0029-8549}, mesh = {Animals ; Aphids/*parasitology/*physiology ; Female ; Host-Parasite Interactions ; Male ; Reproduction ; Sexual Behavior, Animal ; }, abstract = {In haplodiploid organisms, virgin females can produce offspring, albeit only sons. They may therefore face a trade-off between either: (1) searching for hosts and producing sons immediately; or (2) searching for mates and perhaps producing both sons and daughters later in life. Although this trade-off raises a theoretical interest, it has not been approached experimentally. The objective of this article is thus to document the effect of mating status on the foraging behavior of a haplodiploid parasitoid. For this, we recorded the behavior of virgin and mated female Lysiphlebus testaceipes (Hymenoptera: Braconidae) after being released, in the field, on a colony of their aphid hosts. Half of the virgin females were mated by a wild male after less than 10 min of foraging. Evidently, virgin females attract males while foraging on host patches, so that the two activities are not mutually exclusive. Nonetheless, virgin females stayed motionless more often and for longer periods than mated females. Consequently, they attacked aphids at a lower rate, and in turn, attacked fewer aphids on each patch. Moreover, contrary to mated females, virgins did not aggregate their progeny on large patches. We conclude that in L. testaceipes, the trade-off may not be as hypothesized. By dispersing across patches more than mated females, virgins could promote future mating opportunities for their sons and increase their inclusive fitness. However, by moving too frequently, females may lose immediate mating opportunities for themselves and the immediate advantage of producing offspring of both sexes. The observed behavior of virgin L. testaceipes females on host patches could reflect an optimal solution to such a trade-off.}, } @article {pmid18442836, year = {2008}, author = {Roze, D and Rousset, F}, title = {Multilocus models in the infinite island model of population structure.}, journal = {Theoretical population biology}, volume = {73}, number = {4}, pages = {529-542}, doi = {10.1016/j.tpb.2008.03.002}, pmid = {18442836}, issn = {1096-0325}, mesh = {Animals ; Biological Evolution ; Diploidy ; Gene Frequency ; Genetic Linkage ; *Genetics, Population ; Haploidy ; Life Cycle Stages ; *Models, Genetic ; Population Dynamics ; Quantitative Trait Loci ; Reproduction/physiology ; Selection, Genetic ; }, abstract = {Different methods have been developed to consider the effects of statistical associations among genes that arise in population genetics models: kin selection models deal with associations among genes present in different interacting individuals, while multilocus models deal with associations among genes at different loci. It was pointed out recently that these two types of models are very similar in essence. In this paper, we present a method to construct multilocus models in the infinite island model of population structure (where deme size may be arbitrarily small). This method allows one to compute recursions on allele frequencies, and different types of genetic associations (including associations between different individuals from the same deme), and incorporates selection. Recursions can be simplified using quasi-equilibrium approximations; however, we show that quasi-equilibrium calculations for associations that are different from zero under neutrality must include a term that has not been previously considered. The method is illustrated using simple examples.}, } @article {pmid18422930, year = {2008}, author = {Knopp, T and Heimovirta, M and Kokko, H and Merilä, J}, title = {Do male moor frogs (Rana arvalis) lek with kin?.}, journal = {Molecular ecology}, volume = {17}, number = {10}, pages = {2522-2530}, doi = {10.1111/j.1365-294X.2008.03748.x}, pmid = {18422930}, issn = {1365-294X}, mesh = {Animals ; *Genetic Variation ; Male ; Microsatellite Repeats/genetics ; Ranidae/*genetics/physiology ; *Sexual Behavior, Animal ; Sweden ; }, abstract = {Many amphibian species are known to form leks during breeding season, yet it has seldom been tested which evolutionary forces are likely to act on lek formation in this taxon. We tested the kin selection hypothesis for lek formation by using eight variable microsatellite loci to compare the genetic relationship of 203 males in seven Rana arvalis leks. The results indicate that moor frog males do not lek with kin: their relatedness within leks was not higher than expected by chance. Furthermore, spatially distinct leks within same water bodies could not be distinguished from each other as separate units. These results are not expected if kin selection underlie lek formation. On the basis of these results and general knowledge of anuran breeding biology, we suggest that lek formation in explosively breeding amphibians might have evolved by female choice for breeding aggregations, combined with female choice of habitat. Future work should aim at predicting aggregations based on rules of phonotaxis over different spatial scales, and empirical work should document visitation rates not only for leks of a specific size, but also for different travel distances that visiting females may have had to cover.}, } @article {pmid18409383, year = {2008}, author = {Provorov, NA and Vorob'ev, NI and Andronov, EE}, title = {[Macro- and microevolution of bacteria in symbiotic systems].}, journal = {Genetika}, volume = {44}, number = {1}, pages = {12-28}, pmid = {18409383}, issn = {0016-6758}, mesh = {Bacteria/*genetics/metabolism ; *Bacterial Physiological Phenomena ; *Evolution, Molecular ; Genetic Drift ; Genome, Bacterial/physiology ; Genome, Plant/physiology ; *Plant Physiological Phenomena ; Plants/*genetics/metabolism ; Selection, Genetic ; Symbiosis/*physiology ; }, abstract = {Using the examples of diverse interactions among prokaryotes and eukaryotes, the relationships between molecular and population mechanisms of evolution of symbiotic bacteria are addressed. Their circulation in host-environment systems activates microevolutionary factors that direct combinative or reductive genome evolution in facultative, ecologically obligatory, and genetically obligatory symbioses. Due to intense systemic intra-genome rearrangements and horizontal gene transfer, two types of gene systems evolve in these bacteria: (1) controlling the pathogenesis-like processes of host recognition and penetration and (2) responsible for mutualistic interactions that are related to nitrogen fixation and its transfer to the host. The evolution of gene systems of type 1 is directed by individual (Darwinian, frequency-dependent) selection, which is responsible for gene-for-gene interactions between the partners. In the evolution of the type 2 systems, group (interdeme, kin) selection plays the key role, being responsible for the development of bacterial traits beneficial for the host. Using the legume--rhizobia symbiosis as an example, it is shown that evolution of mutualism can be described in terms of biological altruism, whose regularities are common for intraspecific and interspecific relationships. Macroevolutionary rearrangements of bacterial genomes result from the structural changes in their populations, wherein various selection modes are combined with stochastic processes (genetic drift, population waves) induced in the symbiotic systems.}, } @article {pmid18389201, year = {2008}, author = {Heinze, J}, title = {Hierarchy length in orphaned colonies of the ant Temnothorax nylanderi.}, journal = {Die Naturwissenschaften}, volume = {95}, number = {8}, pages = {757-760}, pmid = {18389201}, issn = {0028-1042}, mesh = {*Aggression ; Animals ; Ants/*anatomy & histology/genetics ; Body Size ; Female ; Male ; Models, Biological ; Ovum ; Reproduction ; Sexual Behavior, Animal ; Social Behavior ; *Social Dominance ; }, abstract = {Workers of the ant Temnothorax nylanderi form dominance orders in orphaned colonies in which only one or a few top-ranking workers begin to produce males from unfertilized eggs. Between one and 11 individuals initiated 80% of all aggression in 14 queenless colonies. As predicted from inclusive fitness models (Molet M, van Baalen M, Monnin T, Insectes Soc 52:247-256, 2005), hierarchy length was found to first increase with colony size and then to level off at larger worker numbers. The frequency and skew of aggression decreased with increasing size, indicating that rank orders are less pronounced in larger colonies.}, } @article {pmid18386099, year = {2008}, author = {Traulsen, A and Shoresh, N and Nowak, MA}, title = {Analytical results for individual and group selection of any intensity.}, journal = {Bulletin of mathematical biology}, volume = {70}, number = {5}, pages = {1410-1424}, pmid = {18386099}, issn = {1522-9602}, support = {R01 GM078986/GM/NIGMS NIH HHS/United States ; R01 GM078986-02/GM/NIGMS NIH HHS/United States ; }, mesh = {Algorithms ; Evolution, Molecular ; Game Theory ; *Genetics, Population ; *Models, Genetic ; *Selection, Genetic ; Stochastic Processes ; }, abstract = {The idea of evolutionary game theory is to relate the payoff of a game to reproductive success (= fitness). An underlying assumption in most models is that fitness is a linear function of the payoff. For stochastic evolutionary dynamics in finite populations, this leads to analytical results in the limit of weak selection, where the game has a small effect on overall fitness. But this linear function makes the analysis of strong selection difficult. Here, we show that analytical results can be obtained for any intensity of selection, if fitness is defined as an exponential function of payoff. This approach also works for group selection (= multi-level selection). We discuss the difference between our approach and that of inclusive fitness theory.}, } @article {pmid18371985, year = {2008}, author = {Grafen, A and Archetti, M}, title = {Natural selection of altruism in inelastic viscous homogeneous populations.}, journal = {Journal of theoretical biology}, volume = {252}, number = {4}, pages = {694-710}, doi = {10.1016/j.jtbi.2008.01.021}, pmid = {18371985}, issn = {1095-8541}, mesh = {*Altruism ; Animals ; Biological Evolution ; *Models, Genetic ; Population Density ; Population Dynamics ; *Selection, Genetic ; }, abstract = {Biological explanations are given of three main uninterpreted theoretical results on the selection of altruism in inelastic viscous homogeneous populations, namely that non-overlapping generations hinder the evolution of altruism, fecundity effects are more conducive to altruism than survival effects, and one demographic regime (so-called death-birth) permits altruism whereas another (so-called birth-death) does not. The central idea is 'circles of compensation', which measure how far the effects of density dependence extend from a focal individual. Relatednesses can then be calculated that compensate for density dependence. There is very generally a 'balancing circle of compensation', at which the viscosity of the population slows up selection of altruism, but does not affect its direction, and this holds for altruism towards any individual, not just immediate neighbours. These explanations are possible because of recent advances in the theory of inclusive fitness on graphs. The assumption of node bitransitivity in that recent theory is relaxed to node transitivity and symmetry of the dispersal matrix, and new formulae show how to calculate relatedness from dispersal and vice versa.}, } @article {pmid18331456, year = {2008}, author = {Alizon, S and Taylor, P}, title = {Empty sites can promote altruistic behavior.}, journal = {Evolution; international journal of organic evolution}, volume = {62}, number = {6}, pages = {1335-1344}, doi = {10.1111/j.1558-5646.2008.00369.x}, pmid = {18331456}, issn = {0014-3820}, mesh = {*Altruism ; Computer Simulation ; Fertility/*physiology ; *Models, Theoretical ; *Selection, Genetic ; Spatial Behavior/*physiology ; }, abstract = {Spatial structure has been shown to promote altruistic behavior, however, it also increases the intensity of competition among relatives. Our purpose here is to develop a model in which this competition is minimized, more precisely a local increase in fecundity has a minimal competitive effect on the fitness of nearby individuals. We work with an island model in which sites are allowed to be empty, choosing our demographic rules so that in patches with higher fecundity, empty sites are filled at a higher rate. We also allow dispersal rates to evolve in response to the proportion of empty sites in the patch. Patches with different numbers of empty sites differ in frequency, in within-patch consanguinity, and in reproductive value. Using an inclusive fitness argument, we show that our model does promote altruism; indeed Hamilton's Rule is shown to hold. The only negative effect on an actor of a gift of fecundity to a patchmate turns out to be a slight decrease in reproductive value due to an increased probability of an empty site being occupied. We show that altruists are most favored in islands with an intermediate number of empty sites.}, } @article {pmid18280990, year = {2008}, author = {Lodé, T}, title = {Kin recognition versus familiarity in a solitary mustelid, the European polecat Mustela putorius.}, journal = {Comptes rendus biologies}, volume = {331}, number = {3}, pages = {248-254}, doi = {10.1016/j.crvi.2007.12.006}, pmid = {18280990}, issn = {1631-0691}, mesh = {Aggression ; Aging ; Animals ; Discrimination, Psychological ; Family ; Female ; Ferrets/*psychology ; Male ; Recognition, Psychology ; Sex Characteristics ; Siblings ; *Social Behavior ; }, abstract = {The aim of this experimental study was to investigate kin discrimination in the polecat and to analyse the ontogeny of interactions. Juvenile polecats (ten males and nine females) had been raised under four distinct experimental conditions: 1, kin, familiar; 2, kin, unfamiliar; 3, non-kin, familiar; 4, non-kin, unfamiliar. During dyadic encounters between polecats in neutral enclosures, the number of positive (tolerance), negative (aggression), intermediate (intimidation), and neutral interactions (no direct interactions) were recorded at two different ages of the animals (50 and 70 days old). Male-male encounters were characterised by more aggressive behaviour than female-female ones. The proportion of these negative interactions increased with age, while the proportion of positive interactions decreased. Although aggressive behaviours varied among groups, the reaction did never differ with the kinship. Kin selection theory provides successful explanations for a wide range of phenomena, but our results suggest that multiple mechanisms running simultaneously might be involved in social behaviours. Familiarity clearly influenced the social behaviour of polecats and might be involved in a kin facilitation effect favouring interactions. Animals raised together demonstrated more positive and less negative interactions, so that, despite the individualistic way of life of the polecat, familiarisation may result in more tolerance, emphasising that solitary species may provide significant information on social life. Anyway, familiarisation in polecat may be regarded as a cognitive form of recognition.}, } @article {pmid18264688, year = {2008}, author = {Inbar, S and Katzav-Gozansky, T and Hefetz, A}, title = {Kin composition effects on reproductive competition among queenless honeybee workers.}, journal = {Die Naturwissenschaften}, volume = {95}, number = {5}, pages = {427-432}, pmid = {18264688}, issn = {0028-1042}, mesh = {Animals ; Bees/*physiology ; Female ; Male ; Pheromones/*physiology ; Reproduction ; Sexual Behavior, Animal ; Social Behavior ; }, abstract = {Kin selection and inclusive fitness theories predict that, in hopeless queenless (QL) groups, competition or cooperation will occur over male production among workers of different patrilines. Competition is expected to involve mutual inhibition of reproduction and to affect fertility advertisement. To examine kin effect on these phenomena, we studied QL groups of honeybee workers comprising three types of kin structure: groups composed of pure single patrilines, groups composed of three mixed patrilines (all originating from colonies headed by single-drone-inseminated queens), and control groups composed of bees originating from naturally mated queens. Global assessment of ovarian development, irrespective of patriline composition, revealed no differences among group types. In contrast, the performance of specific patrilines revealed that, in the three-mixed-patriline groups, some patrilines were reproductively suppressed compared to their performance when reared as a pure single patriline, resulting in an uneven share of reproduction. Analysis of the fertility signal produced by Dufour's gland revealed kin composition effects, which may reflect the bees' competitive efforts. Although patriline effects on worker reproductive superiority have been shown in QL colonies, we were able to investigate specific patriline performance both in competitive and noncompetitive situations here for the first time. The results are consistent with the hypothesis that reproductive and pheromonal competitions in QL groups are affected by the number of subfamilies populating a colony and that these act as coalitions. The results also emphasize that within-colony heterogeneity, in the form of multiple patrilines, has far-reaching consequences on social evolution.}, } @article {pmid18252662, year = {2008}, author = {Foote, AD}, title = {Mortality rate acceleration and post-reproductive lifespan in matrilineal whale species.}, journal = {Biology letters}, volume = {4}, number = {2}, pages = {189-191}, pmid = {18252662}, issn = {1744-9561}, mesh = {Aging/*physiology ; Animals ; Female ; Longevity/*physiology ; Mortality ; Reproduction/*physiology ; *Selection, Genetic ; Species Specificity ; Whales/*physiology ; }, abstract = {The strength of selection to increase the span of a life stage is dependent upon individuals at that stage being able to contribute towards individual fitness and the probability of their surviving to that stage. Complete reproductive cessation and a long post-reproductive female lifespan as found in humans are also found in killer whale (Orcinus orca) and short-finned pilot whale (Globicephala macrorhynchus), but not in the long-finned pilot whale (Globicephala melaena). Each species forms kin-based, stable matrilineal groups and exhibits kin-directed behaviours that could increase inclusive fitness. Here, the initial mortality rate and mortality rate-doubling time of females of these three closely related whale species are compared. The initial mortality rate shows little variation among pilot whale species; however mortality rate accelerates almost twice as fast in the long-finned pilot whale as it does in killer whale and short-finned pilot whale. Selection for a long post-reproductive female lifespan in matrilineal whales may therefore be determined by the proportion of females surviving past the point of reproductive cessation.}, } @article {pmid18212805, year = {2008}, author = {Buckling, A and Brockhurst, MA}, title = {Kin selection and the evolution of virulence.}, journal = {Heredity}, volume = {100}, number = {5}, pages = {484-488}, doi = {10.1038/sj.hdy.6801093}, pmid = {18212805}, issn = {1365-2540}, mesh = {Animals ; *Biological Evolution ; Parasites/genetics/*pathogenicity ; Virulence/*genetics ; }, abstract = {Social interactions between conspecific parasites are partly dependent on the relatedness of interacting parasites (kin selection), which, in turn, is predicted to affect the extent of damage they cause their hosts (virulence). High relatedness is generally assumed to favour less competitive interactions, but the relationship between relatedness and virulence is crucially dependent on the social behaviour in question. Here, we discuss the rather limited body of experimental work that addresses how kin-selected social behaviours affect virulence. First, if prudent use of host resources (a form of cooperation) maximizes the transmission success of the parasite population, decreased relatedness is predicted to result in increased host exploitation and virulence. Experimental support for this well-established theoretical result is surprisingly limited. Second, if parasite within-host growth rate is a positive function of cooperation (that is, when individuals need to donate public goods, such as extracellular enzymes), virulence is predicted to increase with increasing relatedness. The limited studies testing this hypothesis are broadly consistent with this prediction. Finally, there is some empirical evidence supporting theory that suggests that spiteful behaviours are maximized at intermediate degrees of relatedness, which, in turn, leads to minimal virulence because of the reduced growth rate of the infecting population. We highlight the need for further thorough experimentation on the role of kin selection in the evolution of virulence and identify additional biological complexities to these simple frameworks.}, } @article {pmid18179515, year = {2008}, author = {Bshary, R and Bergmüller, R}, title = {Distinguishing four fundamental approaches to the evolution of helping.}, journal = {Journal of evolutionary biology}, volume = {21}, number = {2}, pages = {405-420}, doi = {10.1111/j.1420-9101.2007.01482.x}, pmid = {18179515}, issn = {1420-9101}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; Ecosystem ; Game Theory ; Humans ; Selection, Genetic ; Social Sciences ; Terminology as Topic ; }, abstract = {The evolution and stability of helping behaviour has attracted great research efforts across disciplines. However, the field is also characterized by a great confusion over terminology and a number of disagreements, often between disciplines but also along taxonomic boundaries. In an attempt to clarify several issues, we identify four distinct research fields concerning the evolution of helping: (1) basic social evolution theory that studies helping within the framework of Hamilton's inclusive fitness concept, i.e. direct and indirect benefits, (2) an ecological approach that identifies settings that promote life histories or interaction patterns that favour unconditional cooperative and altruistic behaviour, e.g. conditions that lead to interdependency or interactions among kin, (3) the game theoretic approach that identifies strategies that provide feedback and control mechanisms (protecting from cheaters) favouring cooperative behaviour (e.g. pseudo-reciprocity, reciprocity), and (4) the social scientists' approach that particularly emphasizes the special cognitive requirements necessary for human cooperative strategies. The four fields differ with respect to the 'mechanisms' and the 'conditions' favouring helping they investigate. Other major differences concern a focus on either the life-time fitness consequences or the immediate payoff consequences of behaviour, and whether the behaviour of an individual or a whole interaction is considered. We suggest that distinguishing between these four separate fields and their complementary approaches will reduce misunderstandings, facilitating further integration of concepts within and across disciplines.}, } @article {pmid18171147, year = {2008}, author = {Priest, NK and Galloway, LF and Roach, DA}, title = {Mating frequency and inclusive fitness in Drosophila melanogaster.}, journal = {The American naturalist}, volume = {171}, number = {1}, pages = {10-21}, doi = {10.1086/523944}, pmid = {18171147}, issn = {1537-5323}, mesh = {Animals ; Biological Evolution ; Drosophila melanogaster/*genetics ; Female ; Fertility ; Male ; Selection, Genetic ; Sexual Behavior, Animal/*physiology ; }, abstract = {In many species, increased mating frequency reduces maternal survival and reproduction. In order to understand the evolution of mating frequency, we need to determine the consequences of increased mating frequency for offspring. We conducted an experiment in Drosophila melanogaster in which we manipulated the mating frequency of mothers and examined the survival and fecundity of the mothers and their daughters. We found that mothers with the highest mating frequency had accelerated mortality and more rapid reproductive senescence. On average, they had 50% shorter lives and 30% lower lifetime reproductive success (LRS) than did mothers with the lowest mating frequency. However, mothers with the highest mating frequency produced daughters with 28% greater LRS. This finding implies that frequent mating stimulates cross-generational fitness trade-offs such that maternal fitness is reduced while offspring fitness is enhanced. We evaluate these results using a demographic metric of inclusive fitness. We show that the costs and benefits of mating frequency depend on the growth rate of the population. In an inclusive fitness context, there was no evidence that increased mating frequency results in fitness costs for mothers. These results indicate that cross-generational fitness trade-offs have an important role in sexual selection and life-history evolution.}, } @article {pmid18157627, year = {2008}, author = {DeBruine, LM and Jones, BC and Little, AC and Perrett, DI}, title = {Social perception of facial resemblance in humans.}, journal = {Archives of sexual behavior}, volume = {37}, number = {1}, pages = {64-77}, doi = {10.1007/s10508-007-9266-0}, pmid = {18157627}, issn = {0004-0002}, mesh = {Altruism ; Attention ; Choice Behavior ; Cues ; *Face ; *Family ; Female ; Humans ; Inbreeding ; Male ; Marriage/*psychology ; Mental Recall ; Physical Fitness ; Sex Characteristics ; *Social Perception ; *Visual Perception ; }, abstract = {Two lines of reasoning predict that highly social species will have mechanisms to influence behavior toward individuals depending on their degree of relatedness. First, inclusive fitness theory leads to the prediction that organisms will preferentially help closely related kin over more distantly related individuals. Second, evaluation of the relative costs and potential benefits of inbreeding suggests that the degree of kinship should also be considered when choosing a mate. In order to behaviorally discriminate between individuals with different levels of relatedness, organisms must be able to discriminate cues of kinship. Facial resemblance is one such potential cue in humans. Computer-graphic manipulation of face images has made it possible to experimentally test hypotheses about human kin recognition by facial phenotype matching. We review recent experimental evidence that humans respond to facial resemblance in ways consistent with inclusive fitness theory and considerations of the costs of inbreeding, namely by increasing prosocial behavior and positive attributions toward self-resembling images and selectively tempering attributions of attractiveness to other-sex faces in the context of a sexual relationship.}, } @article {pmid18093348, year = {2008}, author = {Pollet, TV and Dunbar, RI}, title = {Childlessness predicts helping of nieces and nephews in United States, 1910.}, journal = {Journal of biosocial science}, volume = {40}, number = {5}, pages = {761-770}, doi = {10.1017/S0021932007002659}, pmid = {18093348}, issn = {1469-7599}, mesh = {Adolescent ; Adult ; Child ; Child Rearing/*history ; Female ; History, 20th Century ; Humans ; Infertility/*epidemiology/history ; *Intergenerational Relations ; Male ; Odds Ratio ; Reproductive Behavior/*history/*statistics & numerical data ; Residence Characteristics/statistics & numerical data ; Socioeconomic Factors ; United States ; }, abstract = {The 'helpers at the nest' hypothesis suggests that individuals who are not currently reproducing often help kin by caretaking and thereby increase their inclusive fitness. Using a large scale historical dataset (Integrated Public Use Microdata Series sample of 1910; n=13,935), the hypothesis is tested that childless couples are more likely to fulfil such a role by taking care of a niece or nephew, but not a parent, than couples with children. Childless couples were significantly more likely to take care of a niece or nephew than couples with children. In contrast, couples with children and childless couples did not differ in caretaking of parents. Childless couples were also more likely to have more and younger nieces/nephews in their home than couples with children.}, } @article {pmid18092991, year = {2007}, author = {Suni, SS and Gignoux, C and Gordon, DM}, title = {Male parentage in dependent-lineage populations of the harvester ant Pogonomyrmex barbatus.}, journal = {Molecular ecology}, volume = {16}, number = {24}, pages = {5149-5155}, doi = {10.1111/j.1365-294X.2007.03492.x}, pmid = {18092991}, issn = {0962-1083}, mesh = {Animals ; Ants/genetics/*physiology ; Female ; Genotype ; Inbreeding ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; Reproduction/physiology ; }, abstract = {We investigated the extent to which workers reproduce in a dependent-lineage population of the monogynous harvester ant Pogonomyrmex barbatus. Dependent-lineage populations contain two interbreeding, yet genetically distinct mitochondrial lineages, each associated with specific alleles at nuclear loci. Workers develop from matings between lineages, and queens develop from matings within lineages, so queens must mate with males of both lineages to produce daughter queens and workers. Males develop from unfertilized eggs and are haploid. Worker production of males could lead to male-mediated gene flow between the lineages if worker-produced males were reproductively capable. This could result in the loss of the dependent-lineage system, because its persistence depends on the maintenance of allelic differences between the lineages. To investigate the extent of worker reproduction in P. barbatus, we genotyped 19-20 males and workers from seven colonies, at seven microsatellite loci, and 1239 additional males at two microsatellite loci. Our methods were powerful enough to detect worker reproduction if workers produced more than 0.39% of males in the population. We detected no worker-produced males; all males appeared to be produced by queens. Thus, worker reproduction is sufficiently infrequent to have little impact on the dependent-lineage system. These results are consistent with predictions based on inclusive fitness theory because the effective queen mating frequency calculated from worker genotypes was 4.26, which is sufficiently high for workers to police those that attempt to reproduce.}, } @article {pmid18082910, year = {2008}, author = {Ratnieks, FL and Wenseleers, T}, title = {Altruism in insect societies and beyond: voluntary or enforced?.}, journal = {Trends in ecology & evolution}, volume = {23}, number = {1}, pages = {45-52}, doi = {10.1016/j.tree.2007.09.013}, pmid = {18082910}, issn = {0169-5347}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; Coercion ; Female ; *Insecta ; Male ; Reproduction/genetics ; }, abstract = {The altruism of insect workers has puzzled researchers for decades. Inclusive fitness theory suggests that high relatedness has been key in promoting such altruism. Recent theory, however, indicates that the intermediate levels of relatedness found within insect societies are too low to directly cause the extreme altruism observed in many species. Instead, recent results show that workers are frequently coerced into acting altruistically. Hence, the altruism seen in many modern-day insect societies is not voluntary but enforced. Here, we also consider the role of coercion in promoting altruism and cooperation in other social systems, such as vertebrate and human societies, and interspecific mutualisms.}, } @article {pmid18070102, year = {2008}, author = {Lion, S and Baalen, Mv}, title = {Self-structuring in spatial evolutionary ecology.}, journal = {Ecology letters}, volume = {11}, number = {3}, pages = {277-295}, doi = {10.1111/j.1461-0248.2007.01132.x}, pmid = {18070102}, issn = {1461-0248}, mesh = {Altruism ; Animals ; *Biological Evolution ; Demography ; *Ecosystem ; Host-Pathogen Interactions ; Interpersonal Relations ; *Models, Biological ; Population Density ; Population Dynamics ; Selection, Genetic ; Virulence ; }, abstract = {Spatial self-structuring has been a focus of recent interest among evolutionary ecologists. We review recent developments in the study of the interplay between spatial self-structuring and evolution. We first discuss the relative merits of the various theoretical approaches to spatial modelling in ecology. Second, we synthesize the main theoretical studies of the evolution of cooperation in spatially structured populations. We show that population viscosity is generally beneficial to cooperation, because cooperators can reap additional benefits from being clustered. A similar mechanism can explain the evolution of honest communication and of reduced virulence in host-parasite interactions. We also discuss some recent innovative empirical results that test these theories. Third, we show the relevance of these results to the general field of evolutionary ecology. An important conclusion is that kin selection is the main process that drives evolution of cooperation in viscous populations. Many results of kin selection theory can be recovered as emergent properties of spatial ecological dynamics. We discuss the implications of these results for the study of multilevel selection and evolutionary transitions. We conclude by sketching some perspectives for future research, with a particular emphasis on the topics of evolutionary branching, criticality, spatial fluctuations and experimental tests of theoretical predictions. Space is the place - Sun Ra.}, } @article {pmid18021204, year = {2008}, author = {Boncoraglio, G and Saino, N}, title = {Barn swallow chicks beg more loudly when broodmates are unrelated.}, journal = {Journal of evolutionary biology}, volume = {21}, number = {1}, pages = {256-262}, doi = {10.1111/j.1420-9101.2007.01441.x}, pmid = {18021204}, issn = {1420-9101}, mesh = {Animals ; *Competitive Behavior ; *Feeding Behavior ; Female ; Male ; *Nesting Behavior ; Swallows/*genetics ; *Vocalization, Animal ; }, abstract = {Parents of a variety of animal species distribute critical resources among their offspring according to the intensity of begging displays. Kin selection theory predicts that offspring behave more selfishly in monopolizing parental care as relatedness with competitors declines. We cross-fostered two eggs between barn swallow (Hirundo rustica) clutches and compared the loudness of begging between mixed and control broods under normal feeding conditions and after a period of food deprivation. Begging loudness was higher in mixed broods under normal but not poor feeding conditions. Survival was reduced in mixed than control broods. Call features varied according to parentage, possibly serving as a cue for self-referent phenotype matching in mixed broods. This is the first evidence within a vertebrate species that competitive behaviour among broodmates depends on their relatedness. Thus, kin recognition and relatedness may be important determinants of communication among family members, care allocation and offspring viability in barn swallows.}, } @article {pmid18020704, year = {2007}, author = {López-Villavicencio, M and Jonot, O and Coantic, A and Hood, ME and Enjalbert, J and Giraud, T}, title = {Multiple infections by the anther smut pathogen are frequent and involve related strains.}, journal = {PLoS pathogens}, volume = {3}, number = {11}, pages = {e176}, pmid = {18020704}, issn = {1553-7374}, mesh = {Genetic Variation ; Genotype ; Host-Parasite Interactions ; Mycoses/*epidemiology/*parasitology ; Plant Diseases/*parasitology ; Polymerase Chain Reaction ; Silene/*parasitology ; Ustilaginales/pathogenicity/*physiology ; }, abstract = {Population models of host-parasite interactions predict that when different parasite genotypes compete within a host for limited resources, those that exploit the host faster will be selected, leading to an increase in parasite virulence. When parasites sharing a host are related, however, kin selection should lead to more cooperative host exploitation that may involve slower rates of parasite reproduction. Despite their potential importance, studies that assess the prevalence of multiple genotype infections in natural populations remain rare, and studies quantifying the relatedness of parasites occurring together as natural multiple infections are particularly scarce. We investigated multiple infections in natural populations of the systemic fungal plant parasite Microbotryum violaceum, the anther smut of Caryophyllaceae, on its host, Silene latifolia. We found that multiple infections can be extremely frequent, with different fungal genotypes found in different stems of single plants. Multiple infections involved parasite genotypes more closely related than would be expected based upon their genetic diversity or due to spatial substructuring within the parasite populations. Together with previous sequential inoculation experiments, our results suggest that M. violaceum actively excludes divergent competitors while tolerating closely related genotypes. Such an exclusion mechanism might explain why multiple infections were less frequent in populations with the highest genetic diversity, which is at odds with intuitive expectations. Thus, these results demonstrate that genetic diversity can influence the prevalence of multiple infections in nature, which will have important consequences for their optimal levels of virulence. Measuring the occurrence of multiple infections and the relatedness among parasites within hosts in natural populations may be important for understanding the evolutionary dynamics of disease, the consequences of vaccine use, and forces driving the population genetic structure of parasites.}, } @article {pmid18004383, year = {2007}, author = {Diggle, SP and Griffin, AS and Campbell, GS and West, SA}, title = {Cooperation and conflict in quorum-sensing bacterial populations.}, journal = {Nature}, volume = {450}, number = {7168}, pages = {411-414}, doi = {10.1038/nature06279}, pmid = {18004383}, issn = {1476-4687}, mesh = {Animals ; Colony Count, Microbial ; Humans ; Models, Biological ; Pseudomonas aeruginosa/genetics/*physiology ; Quorum Sensing/genetics/*physiology ; }, abstract = {It has been suggested that bacterial cells communicate by releasing and sensing small diffusible signal molecules in a process commonly known as quorum sensing (QS). It is generally assumed that QS is used to coordinate cooperative behaviours at the population level. However, evolutionary theory predicts that individuals who communicate and cooperate can be exploited. Here we examine the social evolution of QS experimentally in the opportunistic pathogen Pseudomonas aeruginosa, and show that although QS can provide a benefit at the group level, exploitative individuals can avoid the cost of producing the QS signal or of performing the cooperative behaviour that is coordinated by QS, and can therefore spread. We also show that a solution to the problem of exploitation is kin selection, if interacting bacterial cells tend to be close relatives. These results show that the problem of exploitation, which has been the focus of considerable attention in animal communication, also arises in bacteria.}, } @article {pmid17996103, year = {2007}, author = {Koch, AL}, title = {Evolution of temperate pathogens: the bacteriophage/bacteria paradigm.}, journal = {Virology journal}, volume = {4}, number = {}, pages = {121}, pmid = {17996103}, issn = {1743-422X}, mesh = {Bacteria/*virology ; Bacteriophages/*genetics ; *Evolution, Molecular ; *Genes, Switch ; Models, Biological ; *Models, Genetic ; Virus Physiological Phenomena ; }, abstract = {BACKGROUND: Taking as a pattern, the T4 and lambda viruses interacting with each other and with their Gram-negative host, Escherichia coli, a general model is constructed for the evolution of 'gentle' or temperate pathogens. This model is not simply either pure group or kin selection, but probably is common in a variety of host-parasite pairs in various taxonomic groups. The proposed mechanism is that for its own benefit the pathogen evolved ways to protect its host from attack by other pathogens and this has incidentally protected the host. Although appropriate mechanisms would have been developed and excluded related viral species and also other quite different pathogens, the important advance would have been when other individuals of the same species that arrive at the host subsequent to the first infecting one were excluded.

RESULTS: Such a class of mechanisms would not compete one genotype with another, but simply would be of benefit to the first pathogen that had attacked a host organism.

CONCLUSION: This would tend to protect and extend the life of the host against the detrimental effects of a secondarily infecting pathogen. This leads to the pathogens becoming more temperate via the now favorable co-evolution with its host, which basically protects both host and virus against other pathogens but may cause slowing of the growth of the primary infecting pathogen. Evolution by a 'gentle' strategy would be favored as long as the increased wellbeing of the host also favored the eventual transmission of the early infecting pathogen to other hosts.}, } @article {pmid17991501, year = {2008}, author = {Hausken, K and Hirshleifer, J}, title = {Truthful signalling, the heritability paradox, and the Malthusian equi-marginal principle.}, journal = {Theoretical population biology}, volume = {73}, number = {1}, pages = {11-23}, doi = {10.1016/j.tpb.2007.09.002}, pmid = {17991501}, issn = {0040-5809}, mesh = {*Animal Communication ; Animals ; *Choice Behavior ; Competitive Behavior ; Female ; Male ; Models, Biological ; Models, Statistical ; Population Dynamics ; *Sexual Behavior, Animal ; }, abstract = {The article shows that heritable quality differentials are consistent with the Zahavi Handicap Principle (the Truthful Signalling Hypothesis (TSH)). Earlier analyses have assumed non-heritable quality. The crucial innovation is the Malthusian equi-marginal principle: under selection pressures the relative numbers of higher- and lower-quality organisms will change until, in equilibrium, not the average but the marginal levels of quality will be equalized. Assuming kin selection, each male maximizes his own reproductive success and signals until the marginal value of more signalling is zero. We further require evolutionary stability; displacements to higher or lower population sizes must be restored to equilibrium. The article proposes an alternative to Fisher's [1958. The Genetical Theory of Natural Selection. Dover Publications, Inc., New York [Original publication 1929]] and Hamilton and Zuk's [1982. Heritable true fitness and bright birds: a role for parasites? Science 218, 384-387] suggestions. The model is solvable for ranges of parameters that constitute the stable region. We particularly consider the unit signalling costs of the high- and low-quality males, where it has been widely believed that for a TSH equilibrium the former must be lower than the latter. This article confirms our earlier result that this is not a necessary condition for a truthful signalling equilibrium, though the unit signalling costs of the high-quality males cannot be too much larger.}, } @article {pmid17983464, year = {2008}, author = {Lehmann, L}, title = {The adaptive dynamics of niche constructing traits in spatially subdivided populations: evolving posthumous extended phenotypes.}, journal = {Evolution; international journal of organic evolution}, volume = {62}, number = {3}, pages = {549-566}, doi = {10.1111/j.1558-5646.2007.00291.x}, pmid = {17983464}, issn = {0014-3820}, mesh = {Adaptation, Biological/*physiology ; *Biological Evolution ; *Ecosystem ; *Genetics, Population ; *Models, Biological ; *Phenotype ; Selection, Genetic ; }, abstract = {Niche construction, by which organisms modify the environment in which they live, has been proposed to affect the evolution of many phenotypic traits. But what about the evolution of a niche constructing trait itself, whose expression changes the pattern of natural selection to which the trait is exposed in subsequent generations? This article provides an inclusive fitness analysis of selection on niche constructing phenotypes, which can affect their environment from local to global scales in arbitrarily spatially subdivided populations. The model shows that phenotypic effects of genes extending far beyond the life span of the actor can be affected by natural selection, provided they modify the fitness of those individuals living in the future that are likely to have inherited the niche construction lineage of the actor. Present benefits of behaviors are thus traded off against future indirect costs. The future costs will generally result from a complicated interplay of phenotypic effects, population demography and environmental dynamics. To illustrate these points, I derive the adaptive dynamics of a trait involved in the consumption of an abiotic resource, where resource abundance in future generations feeds back to the evolutionary dynamics of the trait.}, } @article {pmid17972271, year = {2008}, author = {Eberle, M and Kappeler, PM}, title = {Mutualism, reciprocity, or kin selection? Cooperative rescue of a conspecific from a boa in a nocturnal solitary forager the gray mouse lemur.}, journal = {American journal of primatology}, volume = {70}, number = {4}, pages = {410-414}, doi = {10.1002/ajp.20496}, pmid = {17972271}, issn = {0275-2565}, mesh = {Animals ; Behavior, Animal/*physiology ; Cheirogaleidae/genetics/*physiology ; *Cooperative Behavior ; Female ; Madagascar ; Male ; Observation ; Pedigree ; *Selection, Genetic ; }, abstract = {Predator mobbing is a widespread phenomenon in many taxa but the evolution of cooperative mobbing as an adaptive behavior is still subject to debate. Here, we report evidence for cooperative predator defense in a nocturnal solitarily foraging primate, the gray mouse lemur (Microcebus murinus). Several mouse lemurs mobbed a snake that held a non-related male conspecific until he could escape. Evolutionary hypotheses to explain cooperative mobbing include (1) by-product mutualism, when individuals defend others in the process of defending themselves; (2) reciprocity, where animals achieve a higher fitness when helping each other than when they do not cooperate; and (3) kin selection where animals help each other only if they share genes by common descent. Owing to the solitary activity of this species, reciprocity seems to be least likely to explain our observations. By-product mutualism cannot be ruled out entirely but, if costs of snake mobbing are relatively low, the available detailed socio-genetic information indicates that kin selection, rather than any of the other proposed mechanisms, is the primary evolutionary force behind the observed cooperative rescue.}, } @article {pmid17957201, year = {2008}, author = {MacLean, RC}, title = {The tragedy of the commons in microbial populations: insights from theoretical, comparative and experimental studies.}, journal = {Heredity}, volume = {100}, number = {3}, pages = {233-239}, doi = {10.1038/sj.hdy.6801073}, pmid = {17957201}, issn = {1365-2540}, mesh = {Bacteria/*metabolism ; *Biological Evolution ; Competitive Behavior/*physiology ; Genotype ; Metabolic Networks and Pathways/*physiology ; *Models, Biological ; Selection, Genetic ; Thermodynamics ; }, abstract = {First principles of thermodynamics imply that metabolic pathways are faced with a trade-off between the rate and yield of ATP production. Simple evolutionary models argue that this trade-off generates a fundamental social conflict in microbial populations: average fitness in a population is highest if all individuals exploit common resources efficiently, but individual reproductive rate is maximized by consuming common resources at the highest possible rate, a scenario known as the tragedy of the commons. In this paper, I review studies that have addressed two key questions: What is the evidence that the rate-yield trade-off is an evolutionary constraint on metabolic pathways? And, if so, what determines evolutionary outcome of the conflicts generated by this trade-off? Comparative studies and microbial experiments provide evidence that the rate-yield trade-off is an evolutionary constraint that is driven by thermodynamic constraints that are common to all metabolic pathways and pathway-specific constraints that reflect the evolutionary history of populations. Microbial selection experiments show that the evolutionary consequences of this trade-off depend on both kin selection and biochemical constraints. In well-mixed populations with low relatedness, genotypes with rapid and efficient metabolism can coexist as a result of negative frequency-dependent selection generated by density-dependent biochemical costs of rapid metabolism. Kin selection can promote the maintenance of efficient metabolism in structured populations with high relatedness by ensuring that genotypes with efficient metabolic pathways gain an indirect fitness benefit from their competitive restraint. I conclude by suggesting avenues for future research and by discussing the broader implications of this work for microbial social evolution.}, } @article {pmid17956391, year = {2007}, author = {Lehmann, L and Keller, L and Sumpter, DJ}, title = {The evolution of helping and harming on graphs: the return of the inclusive fitness effect.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {6}, pages = {2284-2295}, doi = {10.1111/j.1420-9101.2007.01414.x}, pmid = {17956391}, issn = {1010-061X}, mesh = {*Altruism ; Biological Evolution ; Cooperative Behavior ; Models, Genetic ; Selection, Genetic ; }, abstract = {Evolutionary graph theory has been proposed as providing new fundamental rules for the evolution of co-operation and altruism. But how do these results relate to those of inclusive fitness theory? Here, we carry out a retrospective analysis of the models for the evolution of helping on graphs of Ohtsuki et al. [Nature (2006) 441, 502] and Ohtsuki & Nowak [Proc. R. Soc. Lond. Ser. B Biol. Sci (2006) 273, 2249]. We show that it is possible to translate evolutionary graph theory models into classical kin selection models without disturbing at all the mathematics describing the net effect of selection on helping. Model analysis further demonstrates that costly helping evolves on graphs through limited dispersal and overlapping generations. These two factors are well known to promote relatedness between interacting individuals in spatially structured populations. By allowing more than one individual to live at each node of the graph and by allowing interactions to vary with the distance between nodes, our inclusive fitness model allows us to consider a wider range of biological scenarios leading to the evolution of both helping and harming behaviours on graphs.}, } @article {pmid17956390, year = {2007}, author = {Grafen, A}, title = {An inclusive fitness analysis of altruism on a cyclical network.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {6}, pages = {2278-2283}, doi = {10.1111/j.1420-9101.2007.01413.x}, pmid = {17956390}, issn = {1010-061X}, mesh = {*Altruism ; Biological Evolution ; Cooperative Behavior ; *Models, Genetic ; Population Dynamics ; }, abstract = {A recent model studies the evolution of cooperation on a network, and concludes with a result connecting the benefits and costs of interactions and the number of neighbours. Here, an inclusive fitness analysis is conducted of the only case solved analytically, of a cycle, and the identical result is obtained. This brings the result within a biologically familiar framework. It is notable that the benefits and costs in the inclusive fitness framework need to be derived, and are not the benefits and costs that are the parameters in the original model. The relatedness is a quadratic function of position in a cycle of size N: an individual is related by 1 to itself, by (N - 5)/(N + 1) to an immediate neighbour, and by very close to -1/2 to the most distant individuals. The inclusive fitness analysis explains hitherto puzzling features of the results.}, } @article {pmid17928007, year = {2007}, author = {van Veelen, M and Hopfensitz, A}, title = {In love and war: altruism, norm formation, and two different types of group selection.}, journal = {Journal of theoretical biology}, volume = {249}, number = {4}, pages = {667-680}, doi = {10.1016/j.jtbi.2007.09.007}, pmid = {17928007}, issn = {0022-5193}, mesh = {*Altruism ; Biological Evolution ; Competitive Behavior ; *Group Processes ; Humans ; Markov Chains ; *Models, Genetic ; Models, Psychological ; *Selection, Genetic ; }, abstract = {We analyse simulations reported in "The co-evolution of individual behaviors and social institutions" by Bowles et al., 2003 in the Journal of Theoretical Biology 223, 135-147, and begin with distinguishing two types of group selection models. The literature does not provide different names for them, but they are shown to be fundamentally different and have quite different empirical implications. The working of the first one depends on the answer to the question "is the probability that you also are an altruist large enough", while the other needs an affirmative answer to "are our interests enough in line". The first one therefore can also be understood as a kin selection model, while the working of the second can also be described in terms of the direct benefits. The actual simulation model is a combination of the two. It is also a Markov chain, which has important implications for how the output data should be handled.}, } @article {pmid17926288, year = {2007}, author = {Wild, G and West, SA}, title = {A sex allocation theory for vertebrates: combining local resource competition and condition-dependent allocation.}, journal = {The American naturalist}, volume = {170}, number = {5}, pages = {E112-28}, doi = {10.1086/522057}, pmid = {17926288}, issn = {1537-5323}, mesh = {Animals ; *Behavior, Animal ; Breeding ; *Competitive Behavior ; Female ; Male ; *Models, Biological ; Population Dynamics ; *Sex Ratio ; Vertebrates/*physiology ; }, abstract = {Tests of sex allocation theory in vertebrates are usually based on verbal arguments. However, the operation of multiple selective forces can complicate verbal arguments, possibly making them misleading. We construct an inclusive fitness model for the evolution of condition-dependent brood sex ratio adjustment in response to two leading explanations for sex ratio evolution in vertebrates: the effect of maternal quality on the fitness of male and female offspring (the Trivers-Willard hypothesis [TWH]) and local resource competition (LRC) between females. We show (1) the population sex ratio can be either unbiased or biased in either direction (toward either males or females); (2) brood sex ratio adjustment can be biased in either direction, with high-quality females biasing reproductive investment toward production of sons (as predicted by the TWH) or production of daughters (opposite to predictions of the TWH); and (3) selection can favor gradual sex ratio adjustment, with both sons and daughters being produced by both high- and low-quality mothers. Despite these complications, clear a priori predictions can be made for how the population sex ratio and the conditional sex ratio adjustment of broods should vary across populations or species, and within populations, across individuals of different quality.}, } @article {pmid17919300, year = {2007}, author = {Buckling, A and Harrison, F and Vos, M and Brockhurst, MA and Gardner, A and West, SA and Griffin, A}, title = {Siderophore-mediated cooperation and virulence in Pseudomonas aeruginosa.}, journal = {FEMS microbiology ecology}, volume = {62}, number = {2}, pages = {135-141}, doi = {10.1111/j.1574-6941.2007.00388.x}, pmid = {17919300}, issn = {0168-6496}, mesh = {Animals ; Ecosystem ; Moths/microbiology ; Mutation ; Oligopeptides/physiology ; Pseudomonas Infections/*microbiology ; Pseudomonas aeruginosa/genetics/pathogenicity/*physiology ; Selection, Genetic ; Siderophores/*physiology ; Virulence ; }, abstract = {Why should organisms cooperate with each other? Helping close relatives that are likely to share the same genes (kin selection) is one important explanation that is likely to apply across taxa. The production of metabolically costly extracellular iron-scavenging molecules (siderophores) by microorganisms is a cooperative behaviour because it benefits nearby conspecifics. We review experiments focusing on the production of the primary siderophore (pyoverdin) of the opportunistic bacterial pathogen, Pseudomonas aeruginosa, which test kin selection theories that seek to explain the evolution of cooperation. First, cooperation is indeed favoured when individuals interact with their close relatives and when there is competition between groups of cooperators and noncooperators, such that the benefit of cooperation can be realized. Second, the relative success of cheats and cooperators is a function of their frequencies within populations. Third, elevated mutation rates can confer a selective disadvantage under conditions when cooperation is beneficial, because high mutation rates reduce how closely bacteria are related to each other. Fourth, cooperative pyoverdin production is also shown to be favoured by kin selection in vivo (caterpillars), and results in more virulent infections. Finally, we briefly outline ongoing and future work using this experimental system.}, } @article {pmid17879185, year = {2007}, author = {Ross-Gillespie, A and Gardner, A and West, SA and Griffin, AS}, title = {Frequency dependence and cooperation: theory and a test with bacteria.}, journal = {The American naturalist}, volume = {170}, number = {3}, pages = {331-342}, doi = {10.1086/519860}, pmid = {17879185}, issn = {1537-5323}, mesh = {Ecosystem ; Iron/metabolism ; *Models, Biological ; Mutation ; Pseudomonas aeruginosa/*physiology ; Selection, Genetic ; Siderophores/*metabolism ; }, abstract = {Hamilton's inclusive fitness theory provides a leading explanation for the problem of cooperation. A general result from inclusive fitness theory is that, except under restrictive conditions, cooperation should not be subject to frequency-dependent selection. However, several recent studies in microbial systems have demonstrated that the relative fitness of cheaters, which do not cooperate, is greater when cheaters are rarer. Here we demonstrate theoretically that such frequency-dependent selection can occur in microbes when there is (1) sufficient population structuring or (2) an association between the level of cooperation and total population growth. We test prediction (2) and its underlying assumption, using the pathogenic bacterium Pseudomonas aeruginosa, by competing strains that produce iron-scavenging siderophore molecules (cooperators) with nonproducers (cheaters) at various ratios, under conditions that minimize population structuring. We found that both the relative fitness of cheaters and the productivity of the mixed culture were significantly negatively related to initial cheater frequency. Furthermore, when the period of population growth was experimentally shortened, the strength of frequency dependence was reduced. More generally, we argue that frequency-dependent selection on cooperative traits may be more common in microbes than in metazoans because strong selection, structuring, and cooperation-dependent growth will be more common in microbial populations.}, } @article {pmid17878141, year = {2007}, author = {Shanley, DP and Sear, R and Mace, R and Kirkwood, TB}, title = {Testing evolutionary theories of menopause.}, journal = {Proceedings. Biological sciences}, volume = {274}, number = {1628}, pages = {2943-2949}, pmid = {17878141}, issn = {0962-8452}, support = {/WT_/Wellcome Trust/United Kingdom ; BB/C008200/1/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Adult ; Age Factors ; Aged ; *Biological Evolution ; Female ; Fertility ; Gambia ; Humans ; *Menopause ; Middle Aged ; Models, Biological ; }, abstract = {Why do women cease fertility rather abruptly through menopause at an age well before generalized senescence renders child rearing biologically impossible? The two main evolutionary hypotheses are that menopause serves either (i) to protect mothers from rising age-specific maternal mortality risks, thereby protecting their highly dependent younger children from death if the mother dies or (ii) to provide post-reproductive grandmothers who enhance their inclusive fitness by helping to care and provide for their daughters' children. Recent theoretical work indicates that both factors together are necessary if menopause is to provide an evolutionary advantage. However, these ideas need to be tested using detailed data from actual human life histories lived under reasonably 'natural' conditions; for obvious reasons, such data are extremely scarce. We here describe a study based on a remarkably complete dataset from The Gambia. The data provided quantitative estimates for key parameters for the theoretical model, which were then used to assess the actual effects on fitness. Empirically based numerical analysis of this nature is essential if the enigma of menopause is to be explained satisfactorily in evolutionary terms. Our results point to the distinctive (and perhaps unique) role of menopause in human evolution and provide important support for the hypothesized evolutionary significance of grandmothers.}, } @article {pmid17874366, year = {2007}, author = {Lion, S and van Baalen, M}, title = {From infanticide to parental care: why spatial structure can help adults be good parents.}, journal = {The American naturalist}, volume = {170}, number = {2}, pages = {E26-46}, doi = {10.1086/519462}, pmid = {17874366}, issn = {1537-5323}, mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; *Cannibalism ; *Models, Biological ; Population Dynamics ; }, abstract = {We investigate the evolution of parental care and cannibalism in a spatially structured population where adults can either help or kill juveniles in their neighborhood. We show that spatial structure can reverse the selective pressures on adult behavior, leading to the evolution of parental care, whereas the nonspatial model predicts that cannibalism is the sole evolutionary outcome. Our analysis emphasizes that evolution of such spatially structured populations is best understood at the level of the cluster of invading mutants, and we define invasion fitness as the growth rate of that cluster. We derive an analytical expression for the selective pressures on the trait and show that relatedness and Hamilton's rule are recovered as emergent properties of the spatial ecological dynamics. When adults can also help other adults, the benefits to each class of recipients are weighted by the class reproductive value, a result consistent with that of other models of kin selection. Finally, we advocate a different approach to moment equations and argue that even though the development of moment closure approximations is a necessary line of research, much-needed ecological and evolutionary insight can be gained by studying the unclosed moment equations.}, } @article {pmid17868291, year = {2007}, author = {Kümmerli, R and Keller, L}, title = {Contrasting population genetic structure for workers and queens in the putatively unicolonial ant Formica exsecta.}, journal = {Molecular ecology}, volume = {16}, number = {21}, pages = {4493-4503}, doi = {10.1111/j.1365-294x.2007.03514.x}, pmid = {17868291}, issn = {0962-1083}, mesh = {Animals ; Ants/*genetics/physiology ; *Behavior, Animal ; Female ; Genetic Linkage ; Genotype ; Male ; Microsatellite Repeats ; Polymorphism, Genetic ; Population Dynamics ; *Social Behavior ; Social Isolation ; }, abstract = {The theory of inclusive fitness provides a powerful explanation for reproductive altruism in social insects, whereby workers gain inclusive fitness benefit by rearing the brood of related queens. Some ant species, however, have unicolonial population structures where multiple nests, each containing numerous queens, are interconnected and individuals move freely between nests. In such cases, nestmate relatedness values may often be indistinguishable from zero, which is problematic for inclusive fitness-based explanations of reproductive altruism. We conducted a detailed population genetic study in the polygynous ant Formica exsecta, which has been suggested to form unicolonial populations in its native habitat. Analyses based on adult workers indeed confirmed a genetic structuring consistent with a unicolonial population structure. However, at the population level the genetic structuring inferred from worker pupae was not consistent with a unicolonial population structure, but rather suggested a multicolonial population structure of extended family-based nests. These contrasting patterns suggest limited queen dispersal and free adult worker dispersal. That workers indeed disperse as adults was confirmed by mark-recapture measures showing consistent worker movement between nests. Together, these findings describe a new form of social organization, which possibly also characterizes other ant species forming unicolonial populations in their native habitats. Moreover, the genetic analyses also revealed that while worker nestmate relatedness was indistinguishable from zero at a small geographical scale, it was significantly positive at the population level. This highlights the need to consider the relevant geographical scale when investigating the role of inclusive fitness as a selective force maintaining reproductive altruism.}, } @article {pmid17853999, year = {2007}, author = {Rubenstein, DR}, title = {Temporal but not spatial environmental variation drives adaptive offspring sex allocation in a plural cooperative breeder.}, journal = {The American naturalist}, volume = {170}, number = {1}, pages = {155-165}, doi = {10.1086/518671}, pmid = {17853999}, issn = {1537-5323}, mesh = {*Adaptation, Biological ; Animals ; *Breeding ; *Cooperative Behavior ; *Environment ; Female ; Male ; Models, Biological ; Nesting Behavior ; Sex Determination Processes ; Sex Factors ; Sex Ratio ; Starlings/*physiology ; }, abstract = {Cooperatively breeding birds have been used frequently to study sex allocation because the adaptive value of the sexes partly depends upon the costs and benefits for parents of receiving help. I examined patterns of directional sex allocation in relation to maternal condition (Trivers-Willard hypothesis), territory quality (helper competition hypothesis), and the number of available helpers (helper repayment hypothesis) in the superb starling, Lamprotornis superbus, a plural cooperative breeder with helpers of both sexes. Superb starlings biased their offspring sex ratio in relation to prebreeding rainfall, which was correlated with maternal condition. Mothers produced relatively more female offspring in wetter years, when they were in better condition, and more male offspring in drier years, when they were in poorer condition. There was no relationship between offspring sex ratio and territory quality or the number of available helpers. Although helping was male biased, females had a greater variance in reproductive success than males. These results are consistent with the Trivers-Willard hypothesis and suggest that although females in most cooperatively breeding species make sex allocation decisions to increase their future direct reproductive success, female superb starlings appear to base this decision on their current body condition to increase their own inclusive fitness.}, } @article {pmid17850546, year = {2007}, author = {Zhan, XJ and Zhang, ZJ and Wu, H and Goossens, B and Li, M and Jiang, SW and Bruford, MW and Wei, FW}, title = {Molecular analysis of dispersal in giant pandas.}, journal = {Molecular ecology}, volume = {16}, number = {18}, pages = {3792-3800}, doi = {10.1111/j.1365-294X.2007.03450.x}, pmid = {17850546}, issn = {0962-1083}, mesh = {*Animal Migration ; Animals ; China ; Competitive Behavior ; Feces ; Female ; Genetic Variation ; Genotype ; Male ; Microsatellite Repeats ; Sequence Analysis, DNA ; Sex Factors ; Software ; Ursidae/classification/genetics/*physiology ; }, abstract = {Although dispersal in the giant panda (Ailuropoda melanoleuca) is a demographic mechanism which can potentially counteract the negative effect of habitat fragmentation, little is known about dispersal in this species because of difficulties in observing individuals. Using data from faecal microsatellite genotyping, we compared the spatial distribution of giant pandas in two populations and the proximity of relatives in one key population to infer their dispersal pattern. We conclude that giant pandas exhibit female-biased dispersal because: (i) vAIc (variance of assignment index) for females was significantly larger than for males, suggesting that females comprise both 'local' and 'foreign' genotypes; (ii) the average spatial distance of related female dyads was significantly larger than that of males; (iii) larger r (relatedness), F(ST) (genetic variance among populations) and mAIc (mean of assignment index) values were found in males using the software FSTAT, although the differences were not significant; (iv) males set up territories neighbouring to their birth place; (v) significant population structure using microsatellites with a concomitant lack of mitochondrial structure was found in a previous study, possibly indicating more extensive female dispersal; and (vi) female-biased dispersal was strongly supported by evidence from concomitant ecological studies. Considering previous ecological data and life-history characteristics of the giant panda, female-biased dispersal is most likely to be due to competition for birth dens among females, inbreeding avoidance and enhancing inclusive fitness among related males.}, } @article {pmid17727893, year = {2007}, author = {Taylor, PD and Day, T and Wild, G}, title = {From inclusive fitness to fixation probability in homogeneous structured populations.}, journal = {Journal of theoretical biology}, volume = {249}, number = {1}, pages = {101-110}, doi = {10.1016/j.jtbi.2007.07.006}, pmid = {17727893}, issn = {0022-5193}, mesh = {Animals ; Consanguinity ; Game Theory ; Gene Frequency ; *Models, Genetic ; Population Dynamics ; Probability ; *Selection, Genetic ; *Social Behavior ; }, abstract = {The methods of inclusive fitness provide a powerful analysis of the action of selection on social behaviour. The key component of this analysis is the concept of relatedness R. In infinite populations, a standard method of calculating relatedness coefficients is through coefficients of consanguinity using the notion of genetic identity by descent. In this paper, we show that this approach can also be made to work in finite populations and we assume here that the population has a homogeneous structure, such as an island model. We demonstrate that, under the assumption that genetic effects are small and additive, the resulting formulation of inclusive fitness is equivalent to other significant measures of selection in finite populations, including the change in average allele frequency and fixation probability. The results are illustrated for a model of the evolution of cooperation in a finite island population.}, } @article {pmid17714661, year = {2007}, author = {Boomsma, JJ}, title = {Kin selection versus sexual selection: why the ends do not meet.}, journal = {Current biology : CB}, volume = {17}, number = {16}, pages = {R673-83}, doi = {10.1016/j.cub.2007.06.033}, pmid = {17714661}, issn = {0960-9822}, mesh = {Animals ; *Biological Evolution ; Breeding ; Female ; Insecta/genetics/*physiology ; Male ; *Sexual Behavior, Animal ; }, abstract = {I redevelop the hypothesis that lifetime monogamy is a fundamental condition for the evolution of eusocial lineages with permanent non-reproductive castes, and that later elaborations--such as multiply-mated queens and multi-queen colonies--arose without the re-mating promiscuity that characterizes non-social and cooperative breeding. Sexually selected traits in eusocial lineages are therefore peculiar, and their evolution constrained. Indirect (inclusive) fitness benefits in cooperatively breeding vertebrates appear to be negatively correlated with promiscuity, corroborating that kin selection and sexual selection tend to generally exclude each other. The monogamy window required for transitions from solitary and cooperative breeding towards eusociality implies that the relatedness and benefit-cost variables of Hamilton's rule do not vary at random, but occur in distinct and only partly overlapping combinations in cooperative, eusocial, and derived eusocial breeding systems.}, } @article {pmid17714501, year = {2007}, author = {Jansen, VA and Vitalis, R}, title = {The evolution of dispersal in a Levins' type metapopulation model.}, journal = {Evolution; international journal of organic evolution}, volume = {61}, number = {10}, pages = {2386-2397}, doi = {10.1111/j.1558-5646.2007.00201.x}, pmid = {17714501}, issn = {0014-3820}, mesh = {*Biological Evolution ; *Demography ; Ecosystem ; Extinction, Biological ; Models, Biological ; }, abstract = {We study the evolution of the dispersal rate in a metapopulation model with extinction and colonization dynamics, akin to the model as originally described by Levins. To do so we extend the metapopulation model with a description of the within patch dynamics. By means of a separation of time scales we analytically derive a fitness expression from first principles for this model. The fitness function can be written as an inclusive fitness equation (Hamilton's rule). By recasting this equation in a form that emphasizes the effects of competition we show the effect of the local competition and the local population size on the evolution of dispersal. We find that the evolution of dispersal cannot be easily interpreted in terms of avoidance of kin competition, but rather that increased dispersal reduces the competitive ability. Our model also yields a testable prediction in term of relatedness and life-history parameters.}, } @article {pmid17714295, year = {2007}, author = {Whitlock, MC and Davis, BH and Yeaman, S}, title = {The costs and benefits of resource sharing: reciprocity requires resource heterogeneity.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {5}, pages = {1772-1782}, doi = {10.1111/j.1420-9101.2007.01387.x}, pmid = {17714295}, issn = {1010-061X}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; *Biological Evolution ; Models, Theoretical ; }, abstract = {The evolution of resource sharing requires that the fitness benefits to the recipients be much higher than the costs to the giver, which requires heterogeneity among individuals in the fitness value of acquiring additional resources. We develop four models of the evolution of resource sharing by either direct or indirect reciprocity, with equal or unequal partners. Evolution of resource sharing by reciprocity requires differences between interacting individuals in the fitness value of the resource, and these differences must reverse although previous acts of giving are remembered and both participants survive. Moreover, inequality in the expected reproductive value of the interacting individuals makes reciprocity more difficult to evolve, but may still allow evolution of sharing by kin selection. These constraints suggest that resource sharing should evolve much more frequently by kin selection than by reciprocity, a prediction that is well supported by observations in the natural world.}, } @article {pmid17714275, year = {2007}, author = {Doerr, ED and Doerr, VA}, title = {Positive effects of helpers on reproductive success in the brown treecreeper and the general importance of future benefits.}, journal = {The Journal of animal ecology}, volume = {76}, number = {5}, pages = {966-976}, doi = {10.1111/j.1365-2656.2007.01280.x}, pmid = {17714275}, issn = {0021-8790}, mesh = {Animals ; Behavior, Animal/*physiology ; *Cooperative Behavior ; Female ; Fertility ; *Helping Behavior ; Male ; Nesting Behavior/*physiology ; Reproduction/physiology ; Songbirds/*physiology ; Trees ; }, abstract = {1. Numerous studies of cooperatively breeding species have tested for effects of helpers on reproductive success to evaluate hypotheses for the evolution of cooperation, but relatively few have used experimental or statistical approaches that control for the confounding effects of breeder and territory quality. 2. In the brown treecreeper Climacteris picumnus, most helpers are male offspring of the breeding pair that have delayed dispersal. We analysed 5 years of data (97 territory-years) using hierarchical linear modelling to test for effects of helpers on reproductive success while controlling for confounding factors. 3. The number of helpers was related positively to reproductive success even after controlling for differences between territories and breeders. A threshold effect was observed, with success increasing most with the presence of a second helper (i.e. at group size of four). 4. Feeding at the nest was one mechanism responsible for this effect, as larger groups had higher total feeding rates at all nesting stages. Higher total feeding rates, as well as higher feeding rates by helpers, were correlated in turn with greater reproductive success. 5. An analysis of the effects of helper feeding rate on reproductive success in groups with just one helper produced only weak support for a positive effect of helpers. Controlled comparisons of this kind utilize only a small fraction of the total data available and thus have limited statistical power compared to hierarchical or mixed-modelling. 6. A number of hypotheses to explain the evolution and maintenance of helping behaviour are consistent with our results for brown treecreepers including kin selection and hypotheses based on future direct benefits. 7. A previous synthesis of studies of helper effects that controlled for confounding factors suggested a pattern in which male helpers rarely have positive effects on reproductive success. However, revising that synthesis to include recent hierarchical or mixed-modelling studies suggests that helpers of both sexes usually have positive effects, and that the relative importance of future direct benefits may have been underestimated.}, } @article {pmid17711471, year = {2007}, author = {Taylor, C and Nowak, MA}, title = {Transforming the dilemma.}, journal = {Evolution; international journal of organic evolution}, volume = {61}, number = {10}, pages = {2281-2292}, pmid = {17711471}, issn = {0014-3820}, support = {R01 GM078986/GM/NIGMS NIH HHS/United States ; R01 GM078986-02/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; *Cooperative Behavior ; *Game Theory ; Humans ; *Models, Biological ; *Selection, Genetic ; Stochastic Processes ; }, abstract = {How does natural selection lead to cooperation between competing individuals? The Prisoner's Dilemma captures the essence of this problem. Two players can either cooperate or defect. The payoff for mutual cooperation, R, is greater than the payoff for mutual defection, P. But a defector versus a cooperator receives the highest payoff, T, where as the cooperator obtains the lowest payoff, S. Hence, the Prisoner's Dilemma is defined by the payoff ranking T > R > P > S. In a well-mixed population, defectors always have a higher expected payoff than cooperators, and therefore natural selection favors defectors. The evolution of cooperation requires specific mechanisms. Here we discuss five mechanisms for the evolution of cooperation: direct reciprocity, indirect reciprocity, kin selection, group selection, and network reciprocity (or graph selection). Each mechanism leads to a transformation of the Prisoner's Dilemma payoff matrix. From the transformed matrices, we derive the fundamental conditions for the evolution of cooperation. The transformed matrices can be used in standard frameworks of evolutionary dynamics such as the replicator equation or stochastic processes of game dynamics in finite populations.}, } @article {pmid17711149, year = {2007}, author = {Eggers, S and Hashimoto, DM and Kirchengast, S}, title = {An evolutionary approach to explain the high frequency of the polycystic ovary syndrome (PCOS).}, journal = {Anthropologischer Anzeiger; Bericht uber die biologisch-anthropologische Literatur}, volume = {65}, number = {2}, pages = {169-179}, pmid = {17711149}, issn = {0003-5548}, mesh = {Altruism ; Animals ; *Biological Evolution ; Child Rearing ; Cross-Sectional Studies ; Family ; Female ; Humans ; Infant ; Infant Mortality ; Infant, Newborn ; Infertility, Female/*epidemiology ; Polycystic Ovary Syndrome/*epidemiology/genetics/psychology ; Pregnancy ; Primates ; }, abstract = {Infertility and sterility are worldwide phenomena with a long history. At a first glance a condition causing sterility seems to be paradox in an evolutionary sense because it contradicts the biogenetical imperative. In the present paper an evolutionary explanation for the high prevalence rate of PCOS, the most common endocrine disorder causing female infertility, is presented. The symptomatology of PCOS is described and the high prevalence rates of PCOS are explained by means of Darwinian medicine, kin selection and allomothering.}, } @article {pmid17710151, year = {2007}, author = {Gardner, A and West, SA and Griffin, AS}, title = {Is bacterial persistence a social trait?.}, journal = {PloS one}, volume = {2}, number = {8}, pages = {e752}, pmid = {17710151}, issn = {1932-6203}, mesh = {Anti-Bacterial Agents/pharmacology ; Bacteria/drug effects/genetics/*metabolism ; Biological Evolution ; Drug Resistance, Bacterial/physiology ; *Models, Biological ; *Population Dynamics ; Stochastic Processes ; }, abstract = {The ability of bacteria to evolve resistance to antibiotics has been much reported in recent years. It is less well-known that within populations of bacteria there are cells which are resistant due to a non-inherited phenotypic switch to a slow-growing state. Although such 'persister' cells are receiving increasing attention, the evolutionary forces involved have been relatively ignored. Persistence has a direct benefit to cells because it allows survival during catastrophes-a form of bet-hedging. However, persistence can also provide an indirect benefit to other individuals, because the reduced growth rate can reduce competition for limiting resources. This raises the possibility that persistence is a social trait, which can be influenced by kin selection. We develop a theoretical model to investigate the social consequences of persistence. We predict that selection for persistence is increased when: (a) cells are related (e.g. a single, clonal lineage); and (b) resources are scarce. Our model allows us to predict how the level of persistence should vary with time, across populations, in response to intervention strategies and the level of competition. More generally, our results clarify the links between persistence and other bet-hedging or social behaviours.}, } @article {pmid17703898, year = {2007}, author = {Bergmüller, R and Johnstone, RA and Russell, AF and Bshary, R}, title = {Integrating cooperative breeding into theoretical concepts of cooperation.}, journal = {Behavioural processes}, volume = {76}, number = {2}, pages = {61-72}, doi = {10.1016/j.beproc.2007.07.001}, pmid = {17703898}, issn = {0376-6357}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; *Cooperative Behavior ; *Helping Behavior ; Models, Biological ; Psychological Theory ; Reproduction ; Sexual Behavior, Animal ; Social Behavior ; }, abstract = {In cooperative breeding systems, some individuals help to raise offspring that are not their own. While early explanations for such altruistic behaviour were predominantly based on kin selection, recent evidence suggests that direct benefits may be important in the maintenance of cooperation. To date, however, discussions of cooperative breeding have made little reference to more general theories of cooperation between unrelated individuals (while these theories rarely address cooperative breeding). Here, we attempt to integrate the two fields. We identify four key questions that can be used to categorise different mechanisms for the maintenance of cooperative behaviour: (1) whether or not individuals invest in others; (2) whether or not this initial investment elicits a return investment by the beneficiary; (3) whether the interaction is direct, i.e. between two partners, or indirect (involving third parties) and (4) whether only actions that increase the fitness of the partner or also fitness reducing actions (punishment) are involved in the interaction. Asking these questions with regards to concepts in the literature on cooperative breeding, we found that (a) it is often straightforward to relate these concepts to general mechanisms of cooperation, but that (b) a single term (such as 'pay-to-stay', 'group augmentation' or 'prestige') may sometimes subsume two or more distinct mechanisms, and that (c) at least some mechanisms that are thought to be important in cooperative breeding systems have remained largely unexplored in the theoretical literature on the evolution of cooperation. Future theoretical models should incorporate asymmetries in power and pay off structure caused for instance by dominance hierarchies or partner choice, and the use of N-player games. The key challenges for both theoreticians and empiricists will be to integrate the hitherto disparate fields and to disentangle the parallel effects of kin and non-kin based mechanisms of cooperation.}, } @article {pmid17653685, year = {2007}, author = {Kovacs, JL and Goodisman, MA}, title = {Irregular brood patterns and worker reproduction in social wasps.}, journal = {Die Naturwissenschaften}, volume = {94}, number = {12}, pages = {1011-1014}, pmid = {17653685}, issn = {0028-1042}, mesh = {Animals ; Breeding ; Female ; Male ; Nesting Behavior ; Reproduction ; Social Behavior ; Species Specificity ; Wasps/classification/*physiology ; }, abstract = {The potential for reproductive conflict among colony members exists in all social insect societies. For example, queens and workers may be in conflict over the production of males within colonies. Kin selection theory predicts that in a colony headed by a multiply-mated queen, worker reproduction is prevented by worker policing in the form of differential oophagy. However, few studies have demonstrated that workers actually lay eggs within queenright colonies. The purpose of this study was to determine if workers laid male eggs within unmanipulated queen-right colonies of the polyandrous social wasps Vespula maculifrons and V. squamosa. We focused our analysis on an unusual brood pattern within colonies, multiple egg cells. We were primarily interested in determining if individuals reared in these irregular circumstances were queen or worker offspring. To address this question, we genotyped 318 eggs from eight V. maculifrons and two V. squamosa colonies. No worker reproduction was detected in any of the queenright colonies; all of the eggs found in multiple egg cells were consistent with being queen-produced. However, the frequency of multiple egg cells differed among colonies, suggesting that queens vary in the frequency of errors they make when laying eggs within cells. Finally, we suggest that workers may not be laying eggs within queenright colonies and that worker reproduction may be controlled through mechanisms other than differential oophagy in polyandrous Vespula wasps.}, } @article {pmid17651186, year = {2007}, author = {Wenseleers, T}, title = {Nepotism absent in insect societies - or is it?.}, journal = {Molecular ecology}, volume = {16}, number = {15}, pages = {3063-3065}, doi = {10.1111/j.1365-294X.2007.03313.x}, pmid = {17651186}, issn = {0962-1083}, mesh = {Animals ; Female ; Genotype ; Larva/physiology ; Male ; Microsatellite Repeats ; Models, Biological ; Sex Ratio ; Sexual Behavior, Animal ; *Social Behavior ; *Social Dominance ; Wasps/genetics/*physiology ; }, abstract = {Inclusive fitness theory, put forward by English biologist William Hamilton in 1964, is considered by many as the most important addition to the theory of natural selection since Darwin. One prediction of the theory is that animals should often show a tendency to nepotistically favour close relatives. Goodisman et al. (2007) test this theory for the first time using molecular methods in a vespine wasp, the eastern yellowjacket, Vespula maculifrons. Somewhat surprisingly, nepotism was found to be absent. This begs the question why nepotism is predicted by theory, yet in a growing list of species is shown to be absent. Is inclusive fitness theory in trouble? As we show, it is not: costs and constraints explain the general absence of queen rearing nepotism, and nepotism in insect societies in fact is well supported in the context of male rearing and manipulation of colony sex ratios.}, } @article {pmid17641209, year = {2007}, author = {Dugatkin, LA}, title = {Inclusive fitness theory from Darwin to Hamilton.}, journal = {Genetics}, volume = {176}, number = {3}, pages = {1375-1380}, pmid = {17641209}, issn = {0016-6731}, mesh = {*Biological Evolution ; History, 20th Century ; History, 21st Century ; *Models, Genetic ; Models, Theoretical ; Research/*history ; Selection, Genetic ; Social Behavior ; }, } @article {pmid17623070, year = {2007}, author = {Schrempf, A and Darrouzet, E and Heinze, J}, title = {Mating success and potential male-worker conflict in a male-dimorphic ant.}, journal = {BMC evolutionary biology}, volume = {7}, number = {}, pages = {114}, pmid = {17623070}, issn = {1471-2148}, mesh = {Animals ; Ants/genetics/*physiology ; Female ; Longevity ; Male ; Reproduction ; Sex Characteristics ; *Sexual Behavior, Animal ; }, abstract = {BACKGROUND: Males of many species adjust their reproductive tactics with regard to their condition and status. For example, large males may develop weapons and fight for access to females, whereas small or undernourished males do not express costly weapons or ornaments and sneak copulations. Different condition-dependent reproductive tactics may be associated with unequal average fitness, but the tactic chosen by a given male under given circumstances is thought to result in the highest possible fitness return. The ant species Cardiocondyla obscurior exhibits an environment-controlled polymorphism of docile, winged males and aggressive "ergatoid" males. Ergatoid males, which can replenish their sperm supply throughout their lives, engage in lethal fighting, and attempt to monopolize all female sexuals available in their nests, were previously assumed to gain higher lifetime reproductive success than the peaceful, winged males, which disperse to mate away from the nest and whose spermatogenesis is limited to the first days of adult life. However, precise data on male mating success have as yet not been available.Here, we compare the average mating success of the two male morphs, taking the high mortality rate of immature ergatoid males into account. Because individuals in insect societies may have opposing interests about their own development, we also investigate whether the interests of male larvae coincide with those of the workers and the rest of the society.

RESULTS: When the survival probability of males is taken into account, winged males are more likely to mate multiply and in consequence have a higher estimated average mating success than ergatoid males. Therefore, male larvae are expected to prefer developing into winged instead of ergatoid adults.

CONCLUSION: Though male larvae can expect a higher average mating success when developing into winged males, most colonies produce only ergatoid males under standard conditions. This might point at a novel type of potential kin conflict within the social insect colony. Because workers in insect societies usually control male larval development, ergatoid male production under normal conditions probably reflects the optimal allocation strategy of workers to maximise their inclusive fitness.}, } @article {pmid17584220, year = {2007}, author = {Grafen, A}, title = {The formal Darwinism project: a mid-term report.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {4}, pages = {1243-1254}, doi = {10.1111/j.1420-9101.2007.01321.x}, pmid = {17584220}, issn = {1010-061X}, mesh = {Animals ; *Biological Evolution ; Genetics, Population ; Humans ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {For 8 years I have been pursuing in print an ambitious and at times highly technical programme of work, the 'Formal Darwinism Project', whose essence is to underpin and formalize the fitness optimization ideas used by behavioural ecologists, using a new kind of argument linking the mathematics of motion and the mathematics of optimization. The value of the project is to give stronger support to current practices, and at the same time sharpening theoretical ideas and suggesting principled resolutions of some untidy areas, for example, how to define fitness. The aim is also to unify existing free-standing theoretical structures, such as inclusive fitness theory, Evolutionary Stable Strategy (ESS) theory and bet-hedging theory. The 40-year-old misunderstanding over the meaning of fitness optimization between mathematicians and biologists is explained. Most of the elements required for a general theory have now been implemented, but not together in the same framework, and 'general time' remains to be developed and integrated with the other elements to produce a final unified theory of neo-Darwinian natural selection.}, } @article {pmid17567552, year = {2007}, author = {Dudley, SA and File, AL}, title = {Kin recognition in an annual plant.}, journal = {Biology letters}, volume = {3}, number = {4}, pages = {435-438}, pmid = {17567552}, issn = {1744-9561}, mesh = {Biomass ; Brassicaceae/*growth & development ; *Ecosystem ; Plant Leaves/growth & development ; Plant Roots/growth & development ; }, abstract = {Kin recognition is important in animal social systems. However, though plants often compete with kin, there has been as yet no direct evidence that plants recognize kin in competitive interactions. Here we show in the annual plant Cakile edentula, allocation to roots increased when groups of strangers shared a common pot, but not when groups of siblings shared a pot. Our results demonstrate that plants can discriminate kin in competitive interactions and indicate that the root interactions may provide the cue for kin recognition. Because greater root allocation is argued to increase below-ground competitive ability, the results are consistent with kin selection.}, } @article {pmid17561898, year = {2007}, author = {Mutic, JJ and Wolf, JB}, title = {Indirect genetic effects from ecological interactions in Arabidopsis thaliana.}, journal = {Molecular ecology}, volume = {16}, number = {11}, pages = {2371-2381}, doi = {10.1111/j.1365-294X.2007.03259.x}, pmid = {17561898}, issn = {0962-1083}, mesh = {Arabidopsis/anatomy & histology/*genetics/growth & development ; Biomass ; Ecology ; Flowers/anatomy & histology ; Plant Leaves/anatomy & histology ; *Quantitative Trait Loci ; }, abstract = {Indirect genetic effects arise when genes expressed in one individual affect the expression of traits in other individuals. The importance of indirect genetic effects has been recognized for a diversity of evolutionary processes including kin selection, sexual selection, community structure and multilevel selection, but data regarding their genetic architecture and prevalence throughout the genome remain scarce, especially for interactions between unrelated individuals. Using a set of 411 Bay-0 x Shahdara Arabidopsis recombinant inbred lines grown with Landsberg neighbours, we examined quantitative trait loci (QTL) having direct and indirect effects on size, developmental, and fitness related traits. Using an interval mapping approach, we identified 15 QTL with direct effects and found that 13 of these QTL had significant indirect effects on trait expression in neighbouring plants. These results suggest widespread pleiotropy, as nearly all direct effect QTL have associated pleiotropic indirect effects. Paradoxically, most indirect effects were of the same sign as direct effects, creating a pattern of nearly universal positive pleiotropy that makes most covariances between direct and indirect effects positive. These results are consistent with a complex genetic basis for intraspecific interactions, but suggest that interactions between neighbouring plants are largely positive, rather than negative as would be expected for competition. In addition to their evolutionary and ecological importance, these pleiotropic relationships between DGE and IGE loci have implications for quantitative genetic studies of natural populations as well as experimental design considerations. Additionally, studies that ignore IGEs may over- or underestimate quantitative genetic parameters, as well as the effect of and variance contributed by QTL.}, } @article {pmid17550343, year = {2008}, author = {de Waal, FB}, title = {Putting the altruism back into altruism: the evolution of empathy.}, journal = {Annual review of psychology}, volume = {59}, number = {}, pages = {279-300}, doi = {10.1146/annurev.psych.59.103006.093625}, pmid = {17550343}, issn = {0066-4308}, mesh = {Affect ; *Altruism ; *Biological Evolution ; Cooperative Behavior ; *Empathy ; Humans ; Intention ; Social Behavior ; }, abstract = {Evolutionary theory postulates that altruistic behavior evolved for the return-benefits it bears the performer. For return-benefits to play a motivational role, however, they need to be experienced by the organism. Motivational analyses should restrict themselves, therefore, to the altruistic impulse and its knowable consequences. Empathy is an ideal candidate mechanism to underlie so-called directed altruism, i.e., altruism in response to anothers's pain, need, or distress. Evidence is accumulating that this mechanism is phylogenetically ancient, probably as old as mammals and birds. Perception of the emotional state of another automatically activates shared representations causing a matching emotional state in the observer. With increasing cognition, state-matching evolved into more complex forms, including concern for the other and perspective-taking. Empathy-induced altruism derives its strength from the emotional stake it offers the self in the other's welfare. The dynamics of the empathy mechanism agree with predictions from kin selection and reciprocal altruism theory.}, } @article {pmid17542839, year = {2007}, author = {Schliekelman, P}, title = {Kin selection and evolution of infectious disease resistance.}, journal = {Evolution; international journal of organic evolution}, volume = {61}, number = {6}, pages = {1277-1288}, doi = {10.1111/j.1558-5646.2007.00122.x}, pmid = {17542839}, issn = {0014-3820}, mesh = {Alleles ; Communicable Diseases/*immunology/transmission ; *Evolution, Molecular ; Family ; Humans ; Immunity, Innate/*genetics ; Models, Genetic ; Receptors, CCR5/genetics ; *Selection, Genetic ; }, abstract = {Discoveries of mutations conferring resistance to infectious diseases have led to increased interest in the evolutionary dynamics of disease resistance. Several recent papers have estimated the historical strength of selection for mutations conferring disease resistance. These studies are based on simple population genetic models that do not take account of factors such as spatial and family structure. Such factors may have a substantial impact on the strength of natural selection through inclusive fitness effects. That is, people have a strong tendency to live with relatives and therefore have a high probability of transmitting infectious diseases to them. Thus, an allele that protects an individual against disease infection also protects that individual's family members. Because some of these family members are likely to also be carrying the allele, selection for that allele is magnified by family structure. In this paper, I use mathematical modeling techniques to explore the impact of such kin selection on the strength of selection for infectious disease resistance alleles. I show that if the resistance allele has the same proportional effect on both within- and between-family transmission, then the impact of kin selection is relatively minor. Selection coefficients are increased by 5-35%, with a greater benefit for weaker alleles. The reason is that an individual with a strong resistance allele does not need much protection from infection by family members and thus does not benefit much from their alleles. The effect of kin selection can be dramatic, however, if the resistance allele has a larger effect on between-family transmission than within-family transmission (which can occur if between-family infection rates are much smaller than within-family rates), increasing selection coefficients by as much as two- to threefold. These results show conditions when it is important to consider family structure in estimates of the strength of selection for infectious disease resistance alleles.}, } @article {pmid17542838, year = {2007}, author = {Rose, MR and Rauser, CL and Benford, G and Matos, M and Mueller, LD}, title = {Hamilton's forces of natural selection after forty years.}, journal = {Evolution; international journal of organic evolution}, volume = {61}, number = {6}, pages = {1265-1276}, doi = {10.1111/j.1558-5646.2007.00120.x}, pmid = {17542838}, issn = {0014-3820}, mesh = {Adaptation, Biological ; Age Factors ; Aging ; *Biological Evolution ; Genetics/history ; History, 20th Century ; Hybrid Vigor ; Longevity/genetics ; *Selection, Genetic ; }, abstract = {In 1966, William D. Hamilton published a landmark paper in evolutionary biology: "The Moulding of Senescence by Natural Selection." It is now apparent that this article is as important as his better-known 1964 articles on kin selection. Not only did the 1966 article explain aging, it also supplied the basic scaling forces for natural selection over the entire life history. Like the Lorentz transformations of relativistic physics, Hamilton's Forces of Natural Selection provide an overarching framework for understanding the power of natural selection at early ages, the existence of aging, the timing of aging, the cessation of aging, and the timing of the cessation of aging. His twin Forces show that natural selection shapes survival and fecundity in different ways, so their evolution can be somewhat distinct. Hamilton's Forces also define the context in which genetic variation is shaped. The Forces of Natural Selection are readily manipulable using experimental evolution, allowing the deceleration or acceleration of aging, and the shifting of the transition ages between development, aging, and late life. For these reasons, evolutionary research on the demographic features of life history should be referred to as "Hamiltonian."}, } @article {pmid17522682, year = {2007}, author = {Taylor, PD and Day, T and Wild, G}, title = {Evolution of cooperation in a finite homogeneous graph.}, journal = {Nature}, volume = {447}, number = {7143}, pages = {469-472}, doi = {10.1038/nature05784}, pmid = {17522682}, issn = {1476-4687}, mesh = {Alleles ; *Biological Evolution ; Competitive Behavior/*physiology ; Fertility/physiology ; Humans ; Models, Genetic ; Phenotype ; }, abstract = {Recent theoretical studies of selection in finite structured populations have worked with one of two measures of selective advantage of an allele: fixation probability and inclusive fitness. Each approach has its own analytical strengths, but given certain assumptions they provide equivalent results. In most instances the structure of the population can be specified by a network of nodes connected by edges (that is, a graph), and much of the work here has focused on a continuous-time model of evolution, first described by ref. 11. Working in this context, we provide an inclusive fitness analysis to derive a surprisingly simple analytical condition for the selective advantage of a cooperative allele in any graph for which the structure satisfies a general symmetry condition ('bi-transitivity'). Our results hold for a broad class of population structures, including most of those analysed previously, as well as some for which a direct calculation of fixation probability has appeared intractable. Notably, under some forms of population regulation, the ability of a cooperative allele to invade is seen to be independent of the nature of population structure (and in particular of how game partnerships are specified) and is identical to that for an unstructured population. For other types of population regulation our results reveal that cooperation can invade if players choose partners along relatively 'high-weight' edges.}, } @article {pmid17496139, year = {2007}, author = {Gilbert, OM and Foster, KR and Mehdiabadi, NJ and Strassmann, JE and Queller, DC}, title = {High relatedness maintains multicellular cooperation in a social amoeba by controlling cheater mutants.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {104}, number = {21}, pages = {8913-8917}, pmid = {17496139}, issn = {0027-8424}, support = {T15 LM007093/LM/NLM NIH HHS/United States ; 5T15 LM07093/LM/NLM NIH HHS/United States ; }, mesh = {Animals ; Dictyostelium/*genetics ; Evolution, Molecular ; F-Box Proteins/genetics/metabolism ; Mutant Chimeric Proteins/genetics ; Mutation/genetics ; Protozoan Proteins/genetics/metabolism ; }, abstract = {The control of cheating is important for understanding major transitions in evolution, from the simplest genes to the most complex societies. Cooperative systems can be ruined if cheaters that lower group productivity are able to spread. Kin-selection theory predicts that high genetic relatedness can limit cheating, because separation of cheaters and cooperators limits opportunities to cheat and promotes selection against low-fitness groups of cheaters. Here, we confirm this prediction for the social amoeba Dictyostelium discoideum; relatedness in natural wild groups is so high that socially destructive cheaters should not spread. We illustrate in the laboratory how high relatedness can control a mutant that would destroy cooperation at low relatedness. Finally, we demonstrate that, as predicted, mutant cheaters do not normally harm cooperation in a natural population. Our findings show how altruism is preserved from the disruptive effects of such mutant cheaters and how exceptionally high relatedness among cells is important in promoting the cooperation that underlies multicellular development.}, } @article {pmid17494750, year = {2007}, author = {Strassmann, JE and Queller, DC}, title = {Insect societies as divided organisms: the complexities of purpose and cross-purpose.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {104 Suppl 1}, number = {Suppl 1}, pages = {8619-8626}, pmid = {17494750}, issn = {0027-8424}, mesh = {Animals ; Haploidy ; Insecta/*physiology ; Models, Biological ; Reproduction ; Selection, Genetic ; *Social Behavior ; }, abstract = {Individual organisms are complex in a special way. The organization and function of their parts seem directed toward a purpose: the survival and reproduction of that individual. Groups of organisms are different. They may also be complex, but that is usually because their parts, the individual organisms, are working at cross-purposes. The most obvious exception to this rule is the social insects. Here, the individuals cooperate in complex ways toward the common goal of the success of the colony, even if it means that most of them do not reproduce. Kin selection theory explains how this can evolve. Nonreproductive individuals help in the reproduction of their kin, who share and transmit their genes. Such help is most favored when individuals can give more to their kin than they give up by not reproducing directly. For example, they can remain at their natal site and help defend a valuable resource ("fortress defenders"), or they can ensure that at least one adult survives to care for helpless young ("life insurers"). Although kin selection explains the extensive cooperation and common purpose of social insect colonies, it also predicts a certain amount of cross-purpose and conflict behavior. Kin selection has predicted how workers and queens disagree over sex ratios, how potential queens struggle to be the colony's head, how workers try to produce sons, and how other workers often prevent them. Kin selection analysis of cooperation and conflict in social insects is one of the outstanding achievements of evolutionary theory.}, } @article {pmid17492975, year = {2007}, author = {Nonacs, P}, title = {Tug-of-war has no borders: it is the missing model in reproductive skew theory.}, journal = {Evolution; international journal of organic evolution}, volume = {61}, number = {5}, pages = {1244-1250}, doi = {10.1111/j.1558-5646.2007.00092.x}, pmid = {17492975}, issn = {0014-3820}, mesh = {Animals ; *Cooperative Behavior ; Models, Biological ; *Reproduction ; *Social Dominance ; }, abstract = {Cooperative breeding often results in unequal reproduction between dominant and subordinate group members. Transactional skew models attempt to predict how unequal reproduction can be before the groups themselves become unstable. A number of variants of transactional models have been developed, with a key difference being whether reproduction is controlled by one party or contested by all. It is shown here that ESS solutions for all situations of contested control over reproduction are given by the original tug-of-war model (TOW). Several interesting results follow. First, TOW can escalate enough to destabilize some types of groups. Particularly vulnerable are those that have low relatedness and gain little from cooperative breeding relative to solitary reproduction. Second, TOW can drastically reduce group productivity and especially the inclusive fitness of dominant individuals. Third, these results contrast strongly with those from variants of TOW models that include concessions to maintain group stability. Such models are shown to be special cases of the general and simpler TOW framework, and to have assumptions that may be biologically suspect. Finally, the overall analysis suggests that there is no mechanism within existing TOW framework that will prevent a costly struggle for reproductive control. Because social species rarely exhibit the high levels of aggression predicted by TOW models, alternative evolutionary mechanisms are considered that can limit conflict and produce more mutually beneficial outcomes. The further development of alternative models to predict patterns of reproductive skew are highly recommended.}, } @article {pmid17490945, year = {2007}, author = {Charmantier, A and Keyser, AJ and Promislow, DE}, title = {First evidence for heritable variation in cooperative breeding behaviour.}, journal = {Proceedings. Biological sciences}, volume = {274}, number = {1619}, pages = {1757-1761}, pmid = {17490945}, issn = {0962-8452}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; *Helping Behavior ; Longevity ; Nesting Behavior/*physiology ; Oregon ; Passeriformes/*genetics/physiology ; Pedigree ; Sexual Behavior, Animal/*physiology ; }, abstract = {Understanding the evolution of complex social behaviours, such as cooperative breeding, is a fundamental problem in evolutionary biology, which has attracted much theoretical and empirical interest. Variation within and between species in the frequency of helping behaviour has been typically associated with variation in direct costs and benefits due to ecological constraints, or with indirect fitness payoffs (i.e. kin selection). Here, we provide the first evidence that individual variation in cooperative behaviour within a natural population also has a heritable component. Using a seven-generation pedigree in a wild population of western bluebirds (Sialia mexicana), we show significant heritable variation for the propensity to help rather than breed, as well as for the probability of having a helper at the nest. We also document a strong positive relationship between a bird's lifespan and its prospect of receiving help when breeding, in accordance with earlier comparative studies across species. These findings provide useful insights into the possible mechanisms which have led to the evolution of cooperative breeding and other social systems.}, } @article {pmid17470348, year = {2007}, author = {Lipson, H}, title = {Evolutionary robotics: emergence of communication.}, journal = {Current biology : CB}, volume = {17}, number = {9}, pages = {R330-2}, doi = {10.1016/j.cub.2007.03.003}, pmid = {17470348}, issn = {0960-9822}, mesh = {*Animal Communication ; Animals ; *Biological Evolution ; Competitive Behavior/physiology ; Cooperative Behavior ; Neural Networks, Computer ; Robotics/*methods ; *Selection, Genetic ; }, abstract = {The emergence of communication is considered one of the major transitions in evolution. Recent work using robot-based simulation shows that communication arises spontaneously. While deceptive communication arises in a purely competitive setting, cooperative communication arises only subject to group or kin selection.}, } @article {pmid17465897, year = {2007}, author = {Mäki-Petäys, H and Corander, J and Aalto, J and Liukkonen, T and Helle, P and Orell, M}, title = {No genetic evidence of sex-biased dispersal in a lekking bird, the capercaillie (Tetrao urogallus).}, journal = {Journal of evolutionary biology}, volume = {20}, number = {3}, pages = {865-873}, doi = {10.1111/j.1420-9101.2007.01314.x}, pmid = {17465897}, issn = {1010-061X}, mesh = {*Animal Migration ; Animals ; Bayes Theorem ; Biological Evolution ; DNA, Mitochondrial/chemistry ; Female ; Galliformes/genetics/*physiology ; Gene Flow ; Genetic Markers ; Genetic Variation ; Haplotypes ; Male ; Microsatellite Repeats ; Population Density ; Sex Factors ; *Sexual Behavior, Animal ; }, abstract = {Sex-biased dispersal is often connected to the mating behaviour of the species. Even if patterns of natal dispersal are reasonably well documented for monogamous birds, only a few data are available for polygynous and especially lekking species. We investigated the dispersal of the capercaillie (Tetrao urogallus) by examining sex-specific gene flow among the leks. Genetic information was extracted using nuclear and mitochondrial molecular markers for sexed faecal samples and analysed by novel Bayesian statistical methods. Contrary to the traditional view that the males are highly philopatric and female is the dispersing sex, we found roughly equivalent gross and effective dispersal of the sexes. The level of polygamy has a strong influence on the effective population size and on the effective dispersal. The results do not support the theories that dispersal evolves solely as a result of resource competition or other advantages to males obtained through kin selection in lekking species.}, } @article {pmid17462673, year = {2007}, author = {Wild, G and Traulsen, A}, title = {The different limits of weak selection and the evolutionary dynamics of finite populations.}, journal = {Journal of theoretical biology}, volume = {247}, number = {2}, pages = {382-390}, doi = {10.1016/j.jtbi.2007.03.015}, pmid = {17462673}, issn = {0022-5193}, mesh = {Animals ; *Biological Evolution ; Game Theory ; *Models, Genetic ; Reproduction ; *Selection, Genetic ; }, abstract = {Evolutionary theory often resorts to weak selection, where different individuals have very similar fitness. Here, we relate two ways to introduce weak selection. The first considers evolutionary games described by payoff matrices with similar entries. This approach has recently attracted a lot of interest in the context of evolutionary game dynamics in finite populations. The second way to introduce weak selection is based on small distances in phenotype space and is a standard approach in kin-selection theory. Whereas both frameworks are interchangeable for constant fitness, frequency-dependent selection shows significant differences between them. We point out the difference between both limits of weak selection and discuss the condition under which the differences vanish. It turns out that this condition is fulfilled by the popular parametrization of the prisoner's dilemma in benefits and costs. However, for general payoff matrices differences between the two frameworks prevail.}, } @article {pmid17456276, year = {2007}, author = {Madsen, EA and Tunney, RJ and Fieldman, G and Plotkin, HC and Dunbar, RI and Richardson, JM and McFarland, D}, title = {Kinship and altruism: a cross-cultural experimental study.}, journal = {British journal of psychology (London, England : 1953)}, volume = {98}, number = {Pt 2}, pages = {339-359}, doi = {10.1348/000712606X129213}, pmid = {17456276}, issn = {0007-1269}, mesh = {*Altruism ; Asian People ; Child ; Cross-Cultural Comparison ; Ethnicity ; Family/*psychology ; Female ; Humans ; Male ; Surveys and Questionnaires ; White People ; }, abstract = {Humans are characterized by an unusual level of prosociality. Despite this, considerable indirect evidence suggests that biological kinship plays an important role in altruistic behaviour. All previous reports of the influence of kin selection on human altruism have, however, used correlational (rather than experimental) designs, or imposed only a hypothetical or negligible time cost on participants. Since these research designs fail either to control for confounding variables or to meet the criteria required as a test of Hamilton's rule for kin selection (that the altruist pays a true cost), they fail to establish unequivocally whether kin selection plays a role. We show that individuals from two different cultures behave in accordance with Hamilton's rule by acting more altruistically (imposing a higher physical cost upon themselves) towards more closely related individuals. Three possible sources of confound were ruled out: generational effects, sexual attraction and reciprocity. Performance on the task however did not exhibit a perfect linear relationship with relatedness, which might reflect either the intrusion of other variables (e.g. cultural differences in the way kinship is costed) or that our behavioural measure is insufficiently sensitive to fine-tuned differences in the way individuals view their social world. These findings provide the first unequivocal experimental evidence that kinship plays a role in moderating altruistic behaviour. Kinship thus represents a baseline against which individuals pitch other criteria (including reciprocity, prosociality, obligation and a moral sense) when deciding how to behave towards others.}, } @article {pmid17439857, year = {2007}, author = {Bargum, K and Sundström, L}, title = {Multiple breeders, breeder shifts and inclusive fitness returns in an ant.}, journal = {Proceedings. Biological sciences}, volume = {274}, number = {1617}, pages = {1547-1551}, pmid = {17439857}, issn = {0962-8452}, mesh = {Animals ; Ants/genetics/*physiology ; Female ; Finland ; *Genetics, Population ; Genotype ; *Hierarchy, Social ; Microsatellite Repeats/genetics ; Reproduction/physiology ; *Selection, Genetic ; Sexual Behavior, Animal/*physiology ; }, abstract = {In social insects, colonies may contain multiple reproductively active queens. This leads to potential conflicts over the apportionment of brood maternity, especially with respect to the production of reproductive offspring. We investigated reproductive partitioning in offspring females (gynes) and workers in the ant Formica fusca, and combined this information with data on the genetic returns gained by workers. Our results provide the first evidence that differential reproductive partitioning among breeders can enhance the inclusive fitness returns for sterile individuals that tend non-descendant offspring. Two aspects of reproductive partitioning contribute to this outcome. First, significantly fewer mother queens contribute to gyne (new reproductive females) than to worker brood, such that relatedness increases from worker to gyne brood. Second, and more importantly, adult workers were significantly more related to the reproductive brood raised by the colony, than to the contemporary worker brood. Thus, the observed breeder shift leads to genetic benefits for the adult workers that tend the brood. Our results also have repercussions for genetic population analyses. Given the observed pattern of reproductive partitioning, estimates of effective population size based on worker and gyne samples are not interchangeable.}, } @article {pmid17437563, year = {2007}, author = {Widdig, A}, title = {Paternal kin discrimination: the evidence and likely mechanisms.}, journal = {Biological reviews of the Cambridge Philosophical Society}, volume = {82}, number = {2}, pages = {319-334}, doi = {10.1111/j.1469-185X.2007.00011.x}, pmid = {17437563}, issn = {1464-7931}, mesh = {Animals ; Behavior, Animal/*physiology ; Female ; Inbreeding ; Male ; Odorants ; *Pair Bond ; Phenotype ; Primates/*physiology ; Sexual Behavior, Animal/*physiology ; Siblings ; *Social Behavior ; Species Specificity ; Vocalization, Animal/physiology ; }, abstract = {One of the most important assumptions of kin selection theory is that individuals behave differently towards kin than non-kin. In mammals, there is strong evidence that maternal kin are distinguished from non-kin via familiarity. However, little is known about whether or not mammals can also recognize paternal kin as many female mammals, including primates, mate with multiple males near the time of conception, potentially concealing paternal kinship. Genetic data in several mammalian species with a promiscuous mating system and male-biased dispersal reveal a high skew in male reproduction which leads to co-residing paternal half-siblings. In most primates, individuals also form stable bisexual groups creating opportunities for males to interact with their offspring. Here I consider close paternal kin co-resident in the same social group, such as father-offspring and paternal half-siblings (i.e. animals sharing the same father but who were born to different mothers) and review mammalian studies of paternal kin discrimination. Furthermore, I summarize the most likely mechanisms of paternal kin discrimination (familiarity and phenotype matching). When familiarity is the underlying mechanism, mothers and/or the sire could mediate familiarity among paternal half-siblings as well as between fathers and offspring assuming mothers and/or fathers can assess paternity. When animals use phenotype matching, they might use their fathers' template (when the father is present) or self (when the father is absent) to assess paternal kinship in others. Available evidence suggests that familiarity and phenotype matching might be used for paternal kin discrimination and that both mechanisms might apply to a wide range of social mammals characterized by a high skew in male reproduction and co-residence of paternal kin. Among primates, suggested evidence for phenotype matching can often have an alternative explanation, which emphasizes the crucial importance of controlling for familiarity as a potential confounding variable. However, the mechanism/s used to identify paternal kin might differ within a species (as a function of each individual's specific circumstances) as well as among species (depending upon the key sensory modalities of the species considered). Finally, I discuss the possible cues used in paternal kin discrimination and offer suggestions for future studies.}, } @article {pmid17416674, year = {2007}, author = {Lehmann, L and Keller, L and West, S and Roze, D}, title = {Group selection and kin selection: two concepts but one process.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {104}, number = {16}, pages = {6736-6739}, pmid = {17416674}, issn = {0027-8424}, mesh = {Animals ; Life Cycle Stages/genetics ; *Models, Genetic ; Models, Statistical ; Retrospective Studies ; *Selection, Genetic ; }, abstract = {In a recent paper, Traulsen and Nowak use a multilevel selection model to show that cooperation can be favored by group selection in finite populations [Traulsen A, Nowak M (2006) Proc Natl Acad Sci USA 103:10952-10955]. The authors challenge the view that kin selection may be an appropriate interpretation of their results and state that group selection is a distinctive process "that permeates evolutionary processes from the emergence of the first cells to eusociality and the economics of nations." In this paper, we start by addressing Traulsen and Nowak's challenge and demonstrate that all their results can be obtained by an application of kin selection theory. We then extend Traulsen and Nowak's model to life history conditions that have been previously studied. This allows us to highlight the differences and similarities between Traulsen and Nowak's model and typical kin selection models and also to broaden the scope of their results. Our retrospective analyses of Traulsen and Nowak's model illustrate that it is possible to convert group selection models to kin selection models without disturbing the mathematics describing the net effect of selection on cooperation.}, } @article {pmid17379522, year = {2007}, author = {Brockhurst, MA and Buckling, A and Gardner, A}, title = {Cooperation peaks at intermediate disturbance.}, journal = {Current biology : CB}, volume = {17}, number = {9}, pages = {761-765}, doi = {10.1016/j.cub.2007.02.057}, pmid = {17379522}, issn = {0960-9822}, support = {//Wellcome Trust/United Kingdom ; }, mesh = {Biofilms/*growth & development ; *Biological Evolution ; *Cooperative Behavior ; *Environment ; *Models, Biological ; Population Dynamics ; Pseudomonas fluorescens/*growth & development ; Selection, Genetic ; Sociobiology ; }, abstract = {Explaining cooperation is a challenge for evolutionary biology. Surprisingly, the role of extrinsic ecological parameters remains largely unconsidered. Disturbances are widespread in nature and have evolutionary consequences. We develop a mathematical model predicting that cooperative traits most readily evolve at intermediate disturbance. Under infrequent disturbance, cooperation breaks down through the accumulation of evolved cheats. Higher rates of disturbance prevent this because the resulting bottlenecks increase genetic structuring (relatedness) promoting kin selection for cooperation. However, cooperation cannot be sustained under very frequent disturbance if population density remains below the level required for successful cooperation. We tested these predictions by using cooperative biofilm formation by the bacterium Pseudomonas fluorescens. The proportion of biofilm-forming bacteria peaked at intermediate disturbance, in a manner consistent with model predictions. Under infrequent and intermediate disturbance, most bacteria occupied the biofilm, but the proportion of cheats was higher under less frequent disturbance. Under frequent disturbance, many bacteria did not occupy the biofilm, suggesting that biofilm dwelling was not as beneficial under frequent versus intermediate disturbance. Given the ubiquity of disturbances in nature, these results suggest that they may play a major role in the evolution of social traits in microbes.}, } @article {pmid17374597, year = {2007}, author = {Harrison, F and Buckling, A}, title = {High relatedness selects against hypermutability in bacterial metapopulations.}, journal = {Proceedings. Biological sciences}, volume = {274}, number = {1615}, pages = {1341-1347}, pmid = {17374597}, issn = {0962-8452}, mesh = {Cooperative Behavior ; *Genetics, Population ; Linear Models ; Pseudomonas aeruginosa/*genetics/*growth & development/metabolism ; Siderophores/metabolism ; }, abstract = {Mutation rate and cooperation have important ecological and evolutionary consequences and, moreover, can affect pathogen virulence. While hypermutability accelerates adaptation to novel environments, hypermutable lineages ('mutators') are selected against in well-adapted populations. Using the model organism Pseudomonas aeruginosa, we previously demonstrated a further potential disadvantage to hypermutability, namely, that it can accelerate the breakdown of cooperation. We now investigate how this property of mutators can affect their persistence in metapopulations. Mutator and wild-type bacteria were competed for 250 generations in globally competing metapopulations, imposing conditions of high or low intra-deme relatedness. High relatedness favours cooperating groups, so we predicted that mutators should achieve lower equilibrium frequencies under high relatedness than under low relatedness. This was observed in our study. Consistent with our hypothesis, there was a positive correlation between mean mutator and cheat frequencies. We conclude that when dense population growth requires cooperation, and when cooperation is favoured (high relatedness), demes containing high frequencies of mutators are likely to be selected against because they also contain high frequencies of non-cooperating cheats. We have also identified conditions where mutator lineages are likely to dominate metapopulations; namely, when low relatedness reduces kin selection for cooperation. These results may help to explain clinical distributions of mutator bacteria.}, } @article {pmid17360270, year = {2007}, author = {Diggle, SP and Gardner, A and West, SA and Griffin, AS}, title = {Evolutionary theory of bacterial quorum sensing: when is a signal not a signal?.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {362}, number = {1483}, pages = {1241-1249}, pmid = {17360270}, issn = {0962-8436}, mesh = {*Biological Evolution ; Gram-Negative Bacteria/genetics/*physiology ; Gram-Positive Bacteria/genetics/*physiology ; Models, Biological ; Quorum Sensing/genetics/*physiology ; }, abstract = {The term quorum sensing (QS) is used to describe the communication between bacterial cells, whereby a coordinated population response is controlled by diffusible molecules produced by individuals. QS has not only been described between cells of the same species (intraspecies), but also between species (interspecies) and between bacteria and higher organisms (inter-kingdom). The fact that QS-based communication appears to be widespread among microbes is strange, considering that explaining both cooperation and communication are two of the greatest problems in evolutionary biology. From an evolutionary perspective, intraspecies signalling can be explained using models such as kin selection, but when communication is described between species, it is more difficult to explain. It is probable that in many cases this involves QS molecules being used as 'cues' by other species as a guide to future action or as manipulating molecules whereby one species will 'coerce' a response from another. In these cases, the usage of QS molecules cannot be described as signalling. This review seeks to integrate the evolutionary literature on animal signalling with the microbiological literature on QS, and asks whether QS within bacteria is true signalling or whether these molecules are also used as cues or for the coercion of other cells.}, } @article {pmid17339208, year = {2007}, author = {Lehmann, L and Balloux, F}, title = {Natural selection on fecundity variance in subdivided populations: kin selection meets bet hedging.}, journal = {Genetics}, volume = {176}, number = {1}, pages = {361-377}, pmid = {17339208}, issn = {0016-6731}, mesh = {Animals ; Biological Evolution ; Fertility/*genetics ; Gene Frequency ; Genetic Variation/*genetics ; Humans ; Life Cycle Stages ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {In a series of seminal articles in 1974, 1975, and 1977, J. H. Gillespie challenged the notion that the "fittest" individuals are those that produce on average the highest number of offspring. He showed that in small populations, the variance in fecundity can determine fitness as much as mean fecundity. One likely reason why Gillespie's concept of within-generation bet hedging has been largely ignored is the general consensus that natural populations are of large size. As a consequence, essentially no work has investigated the role of the fecundity variance on the evolutionary stable state of life-history strategies. While typically large, natural populations also tend to be subdivided in local demes connected by migration. Here, we integrate Gillespie's measure of selection for within-generation bet hedging into the inclusive fitness and game theoretic measure of selection for structured populations. The resulting framework demonstrates that selection against high variance in offspring number is a potent force in large, but structured populations. More generally, the results highlight that variance in offspring number will directly affect various life-history strategies, especially those involving kin interaction. The selective pressures on three key traits are directly investigated here, namely within-generation bet hedging, helping behaviors, and the evolutionary stable dispersal rate. The evolutionary dynamics of all three traits are markedly affected by variance in offspring number, although to a different extent and under different demographic conditions.}, } @article {pmid17316699, year = {2007}, author = {van Veelen, M}, title = {Hamilton's missing link.}, journal = {Journal of theoretical biology}, volume = {246}, number = {3}, pages = {551-554}, doi = {10.1016/j.jtbi.2007.01.001}, pmid = {17316699}, issn = {0022-5193}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Game Theory ; Genetics, Population ; Humans ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Hamilton's famous rule was presented in 1964 in a paper called "The genetical theory of social behaviour (I and II)", Journal of Theoretical Biology 7, 1-16, 17-32. The paper contains a mathematical genetical model from which the rule supposedly follows, but it does not provide a link between the paper's central result, which states that selection dynamics take the population to a state where mean inclusive fitness is maximized, and the rule, which states that selection will lead to maximization of individual inclusive fitness. This note provides a condition under which Hamilton's rule does follow from his central result.}, } @article {pmid17316424, year = {2007}, author = {Korb, J}, title = {Workers of a drywood termite do not work.}, journal = {Frontiers in zoology}, volume = {4}, number = {}, pages = {7}, pmid = {17316424}, issn = {1742-9994}, abstract = {BACKGROUND: Social insects (ants, bees, wasps and termites) are considered as prime examples of altruism in which individuals (workers) forego their own reproduction to help other individuals reproduce. Such a behaviour is favoured by natural selection because the workers rear close kin and in doing so enhance their inclusive fitness.

RESULTS: Here I show, however, that this does not generally apply to termite workers which are scarcely investigated. In the basal drywood termite Cryptotermes secundus the 'workers', which form the large majority of a colony, did not stay to raise relatives. There is no brood caring behaviour and they do not engage in costly help. They are large immature offspring that develop into either winged (dispersing) or unwinged (replacement) reproductives and the probability that they did so was unaffected by the number of brood in the nest as a brood addition experiment showed.

CONCLUSION: Thus, in contrast to general perception where termite workers are considered equivalent to workers in Hymenoptera, the 'large immatures' of C. secundus did not behave as workers that help in raising younger siblings. This apparently is not necessary as the colony lives inside its food. These results, which are likely to be typical for wood-dwelling termites, open the possibility that large complex group living can evolve without altruistic helping and that costly altruistic helping by workers in termites evolved only as a second step.}, } @article {pmid17307304, year = {2007}, author = {Maul, A}, title = {An evolutionary interpretation of the significance of physical pain experienced by human females: defloration and childbirth pains.}, journal = {Medical hypotheses}, volume = {69}, number = {2}, pages = {403-409}, doi = {10.1016/j.mehy.2007.01.005}, pmid = {17307304}, issn = {0306-9877}, mesh = {*Biological Evolution ; Coitus/*physiology ; Female ; Humans ; *Hymen/physiopathology ; Labor Pain/*etiology/physiopathology ; Parturition/*physiology ; Pregnancy ; }, abstract = {The phenomena surrounding the pains commonly related to both first coitus and delivery have been addressed rather poorly in previous work, as regards their evolutionary aspects, during the investigation of human sexuality and reproductive behavior. In particular, the function of the hymen and the significance of defloration are largely misunderstood. The present paper aims to analyse the meaning of these two female physical pains in an evolutionary context. Accordingly, childbirth and defloration pains are hypothesized to manifest an adaptation designed to increase inclusive fitness in human evolutionary history. Clearly, the significance of pain as a message is essentially emotional. Indeed, the intense sexual emotions that may precede and/or follow the pain, the breaking and bleeding of the hymen during the first complete sexual act may generate distinctive strong feelings on/from each side of the newly formed couple. As to labor pain, both the shared intimacy with the mother and the emotional background during confinement may create mutual solicitude among the protagonists (i.e. midwifes, father, mother). Such feelings or attitudes may subsequently turn out to be beneficial to all of them, and more particularly to the newborn. As a general consequence, it appears that the two physical pains under consideration may have behavioral implications, in the sense that they contribute to increasing the stability of the connection between partners and thus, indirectly, to the welfare or even the survival (especially in former times) of the newborn child.}, } @article {pmid17305846, year = {2007}, author = {Mondor, EB and Messing, RH}, title = {Direct vs. inclusive fitness in the evolution of aphid cornicle length.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {2}, pages = {807-812}, doi = {10.1111/j.1420-9101.2006.01271.x}, pmid = {17305846}, issn = {1010-061X}, mesh = {Adaptation, Physiological ; Animal Communication ; Animals ; Aphids/*anatomy & histology/classification/physiology ; *Biological Evolution ; Female ; Flight, Animal ; Male ; Phenotype ; Phylogeny ; Selection, Genetic ; Species Specificity ; }, abstract = {By comparing the relative sizes of anatomical structures among phenotypes, selective pressures that shape species' morphologies can be evaluated. Aphids emit droplets containing an alarm pheromone/defensive secretion from unique anatomical structures called cornicles, upon being attacked. As aphids live in colonies of high relatedness, it is uncertain whether direct or inclusive fitness benefits have chiefly promoted cornicle evolution. Morphological measurements for apterous parthenogen, alate parthenogen, female sexual and male sexual morphs of 43 species (21 genera, one subfamily) were assessed to distinguish between the hypotheses that: (1) cornicles evolved for mechanical defence against natural enemies (direct fitness); (2) cornicles evolved for alarm signalling (inclusive fitness); or (3) cornicle length has been largely constrained by flight aerodynamics. Our results generally support the inclusive fitness hypothesis; cornicle length decreases as the relative number and relatedness of offspring decreases. As cornicle length is greatest in apterous parthenogenetic morphs, inclusive fitness benefits of protecting highly related kin may have been a key factor selecting for cornicles, and increased cornicle length, in aphids.}, } @article {pmid17305808, year = {2007}, author = {West, SA and Griffin, AS and Gardner, A}, title = {Social semantics: altruism, cooperation, mutualism, strong reciprocity and group selection.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {2}, pages = {415-432}, doi = {10.1111/j.1420-9101.2006.01258.x}, pmid = {17305808}, issn = {1010-061X}, mesh = {Altruism ; Animals ; *Biological Evolution ; Cooperative Behavior ; Humans ; *Social Behavior ; *Terminology as Topic ; }, abstract = {From an evolutionary perspective, social behaviours are those which have fitness consequences for both the individual that performs the behaviour, and another individual. Over the last 43 years, a huge theoretical and empirical literature has developed on this topic. However, progress is often hindered by poor communication between scientists, with different people using the same term to mean different things, or different terms to mean the same thing. This can obscure what is biologically important, and what is not. The potential for such semantic confusion is greatest with interdisciplinary research. Our aim here is to address issues of semantic confusion that have arisen with research on the problem of cooperation. In particular, we: (i) discuss confusion over the terms kin selection, mutualism, mutual benefit, cooperation, altruism, reciprocal altruism, weak altruism, altruistic punishment, strong reciprocity, group selection and direct fitness; (ii) emphasize the need to distinguish between proximate (mechanism) and ultimate (survival value) explanations of behaviours. We draw examples from all areas, but especially recent work on humans and microbes.}, } @article {pmid17276915, year = {2007}, author = {Thünken, T and Bakker, TC and Baldauf, SA and Kullmann, H}, title = {Active inbreeding in a cichlid fish and its adaptive significance.}, journal = {Current biology : CB}, volume = {17}, number = {3}, pages = {225-229}, doi = {10.1016/j.cub.2006.11.053}, pmid = {17276915}, issn = {0960-9822}, mesh = {*Adaptation, Physiological ; Animals ; Behavior, Animal ; Cichlids/genetics/*physiology ; Crosses, Genetic ; Female ; *Inbreeding ; Male ; *Mating Preference, Animal ; Reproduction ; }, abstract = {Levels of inbreeding are highly variable in natural populations. Inbreeding can be due to random factors (like population size), limited dispersal, or active mate choice for relatives. Because of inbreeding depression, mating with kin is often avoided, although sometimes intermediately related individuals are preferred (optimal outbreeding). However, theory predicts that the advantages of mating with close kin can override the effects of inbreeding depression, but in the animal kingdom, empirical evidence for this is scarce. Here we show that both sexes of Pelvicachromis taeniatus, an African cichlid with biparental brood care, prefer mating with unfamiliar close kin over nonkin, suggesting inclusive fitness advantages for inbreeding individuals. Biparental care requires synchronous behavior among parents. Since parental care is costly, there is a conflict between parents over care, which can reduce offspring fitness. Relatedness is expected to enhance cooperation among individuals. The comparison of the parental behavior of in- and outbreeding pairs showed that related parents were more cooperative and invested more than unrelated parents. Since we found no evidence for inbreeding depression, our results suggest that in P. taeniatus, inbreeding is an advantageous strategy.}, } @article {pmid17254996, year = {2007}, author = {Grafen, A}, title = {Detecting kin selection at work using inclusive fitness.}, journal = {Proceedings. Biological sciences}, volume = {274}, number = {1610}, pages = {713-719}, pmid = {17254996}, issn = {0962-8452}, mesh = {*Altruism ; *Biological Evolution ; Computer Simulation ; Genetics, Population ; *Models, Theoretical ; Population Density ; *Population Dynamics ; *Selection, Genetic ; }, abstract = {A recent model shows that altruism can evolve with limited migration and variable group sizes, and the authors claim that kin selection cannot provide a sufficient explanation of their results. It is demonstrated, using a recent reformulation of Hamilton's original arguments, that the model falls squarely within the scope of inclusive fitness theory, which furthermore shows how to calculate inclusive fitness and the relevant relatedness. A distinction is drawn between inclusive fitness, which is a method of analysing social behaviour; and kin selection, a process that operates through genetic similarity brought about by common ancestry, but not by assortation by genotype or by direct assessment of genetic similarity. The recent model is analysed, and it turns out that kin selection provides a sufficient explanation to considerable quantitative accuracy, contrary to the authors' claims. A parallel analysis is possible and would be illuminating for all models of social behaviour in which individuals' effects on each other's offspring numbers combine additively.}, } @article {pmid17254993, year = {2007}, author = {Masuda, N and Ohtsuki, H}, title = {Tag-based indirect reciprocity by incomplete social information.}, journal = {Proceedings. Biological sciences}, volume = {274}, number = {1610}, pages = {689-695}, pmid = {17254993}, issn = {0962-8452}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; Game Theory ; Humans ; *Models, Theoretical ; *Selection, Genetic ; }, abstract = {Evolution of altruistic behaviour in interacting individuals is accounted for by, for example, kin selection, direct reciprocity, spatially limited interaction and indirect reciprocity. Real social agents, particularly humans, often take actions based on similarity between themselves and others. Although tag-based indirect reciprocity in which altruism occurs exclusively among similar flocks is a natural expectation, its mechanism has not really been established. We propose a model of tag-based indirect reciprocity by assuming that each player may note strategies of others. We show that tag-based altruism can evolve to eradicate other strategies, including unconditional defectors for various initial strategy configurations and parameter sets. A prerequisite for altruism is that the strategy is sometimes, but not always, visible to others. Without visibility of strategies, policing does not take place and defection is optimal. With perfect visibility, what a player does is always witnessed by others and cooperation is optimal. In the intermediate regime, discriminators based on tag proximity, rather than mixture of generous players and defectors, are most likely to evolve. In this situation, altruism is realized based on homophily in which players are exclusively good to similar others.}, } @article {pmid17240339, year = {2007}, author = {Sumner, S and Lucas, E and Barker, J and Isaac, N}, title = {Radio-tagging technology reveals extreme nest-drifting behavior in a eusocial insect.}, journal = {Current biology : CB}, volume = {17}, number = {2}, pages = {140-145}, doi = {10.1016/j.cub.2006.11.064}, pmid = {17240339}, issn = {0960-9822}, mesh = {Animals ; Female ; *Nesting Behavior ; Radio ; *Selection, Genetic ; *Social Behavior ; *Wasps ; }, abstract = {Kin-selection theory underlies our basic understanding of social evolution [1, 2]. Nest drifting in eusocial insects (where workers move between nests) presents a challenge to this paradigm, since a worker should remain as a helper on her natal colony, rather than visit other colonies to which she is less closely related. Here we reveal nest drifting as a strategy by which workers may maximize their indirect fitness by helping on several related nests, preferring those where the marginal return from their help is greatest. By using a novel monitoring technique, radio frequency identification (RFID) tagging, we provide the first accurate estimate of drifting in a eusocial insect: 56% of females drifted in a natural population of the eusocial paper wasp Polistes canadensis, exceeding previous records of drifting in natural populations by more than 30-fold. We demonstrate that drifting cannot be explained through social parasitism, queen succession, mistakes in nest identity, or methodological bias. Instead, workers appear to gain indirect fitness benefits by helping on several related colonies in a viscous population structure. The potential importance of this strategy as a component of the kin-selected benefits for a social insect worker has previously been overlooked because of methodological difficulties in quantifying and studying drifting.}, } @article {pmid17211805, year = {2007}, author = {Gardner, A and West, SA and Barton, NH}, title = {The relation between multilocus population genetics and social evolution theory.}, journal = {The American naturalist}, volume = {169}, number = {2}, pages = {207-226}, doi = {10.1086/510602}, pmid = {17211805}, issn = {1537-5323}, mesh = {Animals ; *Evolution, Molecular ; *Genetics, Population ; *Hierarchy, Social ; Inheritance Patterns ; Linkage Disequilibrium ; Selection, Genetic ; }, abstract = {Evolution at multiple gene positions is complicated. Direct selection on one gene disturbs the evolutionary dynamics of associated genes. Recent years have seen the development of a multilocus methodology for modeling evolution at arbitrary numbers of gene positions with arbitrary dominance and epistatic relations, mode of inheritance, genetic linkage, and recombination. We show that the approach is conceptually analogous to social evolutionary methodology, which focuses on selection acting on associated individuals. In doing so, we (1) make explicit the links between the multilocus methodology and the foundations of social evolution theory, namely, Price's theorem and Hamilton's rule; (2) relate the multilocus approach to levels-of-selection and neighbor-modulated-fitness approaches in social evolution; (3) highlight the equivalence between genetical hitchhiking and kin selection; (4) demonstrate that the multilocus methodology allows for social evolutionary analyses involving coevolution of multiple traits and genetical associations between nonrelatives, including individuals of different species; (5) show that this methodology helps solve problems of dynamic sufficiency in social evolution theory; (6) form links between invasion criteria in multilocus systems and Hamilton's rule of kin selection; (7) illustrate the generality and exactness of Hamilton's rule, which has previously been described as an approximate, heuristic result.}, } @article {pmid17210023, year = {2007}, author = {Taylor, PD and Wild, G and Gardner, A}, title = {Direct fitness or inclusive fitness: how shall we model kin selection?.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {1}, pages = {301-309}, doi = {10.1111/j.1420-9101.2006.01196.x}, pmid = {17210023}, issn = {1010-061X}, mesh = {*Biological Evolution ; Computer Simulation ; Cooperative Behavior ; *Genetics, Population ; *Models, Theoretical ; Reproduction/genetics ; *Selection, Genetic ; Species Specificity ; }, abstract = {Two standard mathematical formulations of kin-selection models can be found. Inclusive fitness is an actor-centred approach, which calculates the fitness effect on a number of recipients of the behaviour of a single actor. Direct fitness is a recipient-centred approach, which calculates the fitness effect on the recipient of the behaviour of a number of actors. Inclusive fitness offers us a powerful heuristic, of choosing behaviour to maximize fitness, but direct fitness can be mathematically easier to work with and has recently emerged as the preferred approach of theoreticians. In this paper, we explore the fundamental connection between these two approaches in both homogeneous and class-structured populations, and we show that under simple assumptions (mainly fair meiosis and weak selection) they provide equivalent formulations, which correspond to the predictions of Price's equation for allele frequency change. We use a couple of examples to highlight differences in their conception and formulation, and we briefly discuss a two-species example in which we have a class of 'actor' that is never a 'recipient', which the standard direct fitness method can handle but the usual inclusive fitness cannot.}, } @article {pmid17210011, year = {2007}, author = {Lehmann, L}, title = {The evolution of trans-generational altruism: kin selection meets niche construction.}, journal = {Journal of evolutionary biology}, volume = {20}, number = {1}, pages = {181-189}, doi = {10.1111/j.1420-9101.2006.01202.x}, pmid = {17210011}, issn = {1010-061X}, mesh = {*Adaptation, Biological ; *Altruism ; *Biological Evolution ; Computer Simulation ; *Models, Theoretical ; *Selection, Genetic ; }, abstract = {A cornerstone result of sociobiology states that limited dispersal can induce kin competition to offset the kin selected benefits of altruism. Several mechanisms have been proposed to circumvent this dilemma but all assume that actors and recipients of altruism interact during the same time period. Here, this assumption is relaxed and a model is developed where individuals express an altruistic act, which results in posthumously helping relatives living in the future. The analysis of this model suggests that kin selected benefits can then feedback on the evolution of the trait in a way that promotes altruistic helping at high rates under limited dispersal. The decoupling of kin competition and kin selected benefits results from the fact that by helping relatives living in the future, an actor is helping individuals that are not in direct competition with itself. A direct consequence is that behaviours which actors gain by reducing the common good of present and future generations can be opposed by kin selection. The present model integrates niche-constructing traits with kin selection theory and delineates demographic and ecological conditions under which altruism can be selected for; and conditions where the 'tragedy of the commons' can be reduced.}, } @article {pmid17158317, year = {2006}, author = {Nowak, MA}, title = {Five rules for the evolution of cooperation.}, journal = {Science (New York, N.Y.)}, volume = {314}, number = {5805}, pages = {1560-1563}, pmid = {17158317}, issn = {1095-9203}, support = {R01 GM078986/GM/NIGMS NIH HHS/United States ; R01 GM078986-04/GM/NIGMS NIH HHS/United States ; 1R01GM078986-01/GM/NIGMS NIH HHS/United States ; }, mesh = {*Biological Evolution ; Community Networks ; *Cooperative Behavior ; Family ; Game Theory ; Helping Behavior ; Humans ; Mathematics ; Selection, Genetic ; }, abstract = {Cooperation is needed for evolution to construct new levels of organization. Genomes, cells, multicellular organisms, social insects, and human society are all based on cooperation. Cooperation means that selfish replicators forgo some of their reproductive potential to help one another. But natural selection implies competition and therefore opposes cooperation unless a specific mechanism is at work. Here I discuss five mechanisms for the evolution of cooperation: kin selection, direct reciprocity, indirect reciprocity, network reciprocity, and group selection. For each mechanism, a simple rule is derived that specifies whether natural selection can lead to cooperation.}, } @article {pmid17148404, year = {2006}, author = {Korb, J}, title = {Limited food induces nepotism in drywood termites.}, journal = {Biology letters}, volume = {2}, number = {3}, pages = {364-366}, pmid = {17148404}, issn = {1744-9561}, mesh = {Animals ; *Biological Evolution ; Competitive Behavior ; *Cooperative Behavior ; Ecology/methods ; Environment ; *Feeding Behavior ; Female ; *Food ; Isoptera/*physiology ; Male ; Models, Biological ; *Reproduction ; *Social Behavior ; }, abstract = {The evolution of cooperation and altruistic behaviour where individuals forego their own reproduction to help others reproduce can be explained by kin selection. Depending on the costs and benefits provided, altruism can be evolutionarily favoured if it is directed at close relatives. A considerable body of data supports the role of relatedness as a key determinant of cooperation and conflict within societies. However, the role of ecological factors and, in particular, how these costs and benefits interact with relatedness remains poorly understood. By studying 16 colonies, here I show that in a drywood termite ecological factors determine the importance of relatedness. In colonies with limited food supply, nestmates restrict cooperative interactions mainly to close relatives, while non-discriminative cooperation occurs when food is abundant. This shows for the first time directly the interaction between ecological conditions and relatedness in shaping cooperation.}, } @article {pmid17148292, year = {2006}, author = {Nonacs, P}, title = {Nepotism and brood reliability in the suppression of worker reproduction in the eusocial Hymenoptera.}, journal = {Biology letters}, volume = {2}, number = {4}, pages = {577-579}, pmid = {17148292}, issn = {1744-9561}, mesh = {Animals ; Bees/growth & development/*physiology ; Female ; Male ; *Models, Biological ; Ovum/growth & development ; Reproduction/physiology ; }, abstract = {In many eusocial Hymenoptera, workers prevent each other from producing male offspring by destroying worker-laid eggs. Kin selection theory predicts that such 'worker policing' behaviour can evolve by increasing the average relatedness between workers and their male brood. Alternatively, if worker-laid eggs are of low relative viability, their replacement would increase the developmental reliability of the brood. Less colony investment in terms of time and resources would be lost on poor males. This gain is independent of the relatedness of the males. Unfortunately, both nepotistic and group efficiency benefits can simultaneously accrue with the replacement of worker-laid eggs. Therefore, worker behaviour towards eggs cannot completely resolve whether both processes have been equally evolutionarily important. Adequate resolution requires the presentation of worker-produced brood of various ages. The stage at which brood are replaced can discriminate whether worker policing occurs owing to a preference for closer genetic kin, a preference for the more reliable brood or both.}, } @article {pmid17148214, year = {2005}, author = {Kleven, O and Jacobsen, F and Robertson, RJ and Lifjeld, JT}, title = {Extrapair mating between relatives in the barn swallow: a role for kin selection?.}, journal = {Biology letters}, volume = {1}, number = {4}, pages = {389-392}, pmid = {17148214}, issn = {1744-9561}, mesh = {Animals ; Female ; *Inbreeding ; Male ; Mating Preference, Animal/*physiology ; Microsatellite Repeats ; Polymorphism, Genetic ; Swallows/*physiology ; }, abstract = {Why do females of many species mate with more than one male? One of the main hypotheses suggests that female promiscuity is an insurance mechanism against the potential detrimental effects of inbreeding. Accordingly, females should preferably mate with less related males in multiple or extrapair mating. Here we analyse paternity, relatedness among mating partners, and relatedness between parents and offspring, in the socially monogamous North American barn swallow (Hirundo rustica erythrogaster). In contrast to the inbreeding avoidance hypothesis, we found that extrapair mating partners were more related than expected by random choice, and tended to be more related than social partners. Furthermore, extrapair mating resulted in genetic parents being more related to their extrapair young than to their withinpair young. We propose a new hypothesis for extrapair mating based on kin selection theory as a possible explanation to these findings.}, } @article {pmid17148146, year = {2005}, author = {Beekman, M and Oldroyd, BP}, title = {Honeybee workers use cues other than egg viability for policing.}, journal = {Biology letters}, volume = {1}, number = {2}, pages = {129-132}, pmid = {17148146}, issn = {1744-9561}, mesh = {Animals ; *Bees ; Cues ; Female ; Oviparity/physiology ; Ovum/*physiology ; Selection, Genetic ; *Social Behavior ; }, abstract = {Worker policing, wherein social insect workers prevent their sisters from reproducing by eating worker-laid eggs, is recognized as a textbook example of kin selection in action. However, the evolutionary basis of policing was recently challenged in a study that suggested that police-workers remove worker-laid eggs not because rearing workers' sons reduces worker fitness, but merely because worker-laid eggs have low viability. Here, we refute Pirk et al.'s conclusions. First, we confirm earlier work that showed equal viability of eggs laid by queens and workers. Second, a statistical analysis of the data of Pirk et al. reveals that their own data do not support the conclusion that worker-laid eggs are policed merely because of their low viability. Third, we present data that unequivocally show that police-workers cannot discriminate between dead and live eggs. Hence, our study seriously weakens the challenge to the kin-selected basis of policing in honeybees.}, } @article {pmid17133858, year = {2006}, author = {Wild, G}, title = {Sex ratios when helpers stay at the nest.}, journal = {Evolution; international journal of organic evolution}, volume = {60}, number = {10}, pages = {2012-2022}, pmid = {17133858}, issn = {0014-3820}, mesh = {Animals ; *Biological Evolution ; Female ; *Helping Behavior ; Male ; Maternal Behavior ; Models, Biological ; Paternal Behavior ; *Sex Ratio ; }, abstract = {This study investigates the evolution of the sex ratio (parental investment in sons) when breeding adults are supported by help provided by nonbreeding individuals of one sex. The study also assumes that the helping sex remains on its natal site to compete for the opportunity to breed, whereas the nonhelping sex disperses. Two kin-selection models are presented, both of which incorporate the age structure found in many natural populations where such helping occurs. The first model assumes that helpers increase the survival of their parents. The second model assumes that helpers are indiscriminant: a helper chooses to increase the survival of a random pair of adults breeding on its natal patch. In both models, sex ratios are not always biased toward the sex that provides the most help. When helpers do not discriminate (second model), the direction of sex-ratio bias is determined solely by the size of the benefit of helping behavior. When this benefit is small, sex-ratio evolution is primarily influenced by local resource competition and sex ratios are biased toward the nonhelping (dispersive) sex. If the benefit of help is large enough, the effect of local resource competition is reduced and sex-ratio bias favors the helpful sex. When helpers help only their parents, the same qualitative relationship exists between the direction of sex-ratio bias and the benefit of helping. In this case, however, the direction of sex-ratio bias is also influenced by the size of the social group, mortality, and which individual (mother or father) controls the sex ratio. This study also investigates a sex-ratio conflict that exists between mates. Helping behavior of nonbreeders can act to alleviate the disparities between the optimal sex ratio from the perspective of a mother and that from the perspective of a father. This consequence of helping has not been previously recognized.}, } @article {pmid17109313, year = {2006}, author = {Wenseleers, T and Ratnieks, FL}, title = {Comparative analysis of worker reproduction and policing in eusocial hymenoptera supports relatedness theory.}, journal = {The American naturalist}, volume = {168}, number = {6}, pages = {E163-79}, doi = {10.1086/508619}, pmid = {17109313}, issn = {1537-5323}, mesh = {Animals ; *Hierarchy, Social ; Hymenoptera/*physiology ; Phylogeny ; Reproduction/physiology ; *Selection, Genetic ; Sexual Behavior, Animal/*physiology ; }, abstract = {In many bees, wasps, and ants, workers police each other in order to prevent individual workers from selfishly producing their own male offspring. Although several factors can selectively favor worker policing, genetic relatedness is considered to be of special importance. In particular, kin selection theory predicts that worker policing should be more common in species where workers are more related to the queen's sons than to other workers' sons. Here we provide strong novel support for this theory based on a comparative analysis of policing and male parentage in 109 species of ants, bees, and wasps. First, an analysis of behavioral data confirms that worker policing occurs more frequently in species where workers are more related to the queen's sons than to other workers' sons. Second, an analysis of male parentage shows that a significantly higher percentage of the males are workers' sons in species where the workers are more related to other workers' sons. Both conclusions also hold if data are analyzed using phylogenetically independent contrasts. Although our analysis provides strong overall support for the theory that relatedness affects kin conflict over male parentage, there is also significant residual variation. Several factors that may explain this variation are discussed.}, } @article {pmid17087973, year = {2007}, author = {Fletcher, JA and Zwick, M}, title = {The evolution of altruism: game theory in multilevel selection and inclusive fitness.}, journal = {Journal of theoretical biology}, volume = {245}, number = {1}, pages = {26-36}, doi = {10.1016/j.jtbi.2006.09.030}, pmid = {17087973}, issn = {0022-5193}, mesh = {*Altruism ; *Biological Evolution ; Competitive Behavior ; Cooperative Behavior ; Game Theory ; Humans ; Mathematics ; Models, Psychological ; Selection, Genetic ; }, abstract = {Although the prisoner's dilemma (PD) has been used extensively to study reciprocal altruism, here we show that the n-player prisoner's dilemma (NPD) is also central to two other prominent theories of the evolution of altruism: inclusive fitness and multilevel selection. An NPD model captures the essential factors for the evolution of altruism directly in its parameters and integrates important aspects of these two theories such as Hamilton's rule, Simpson's paradox, and the Price covariance equation. The model also suggests a simple interpretation of the Price selection decomposition and an alternative decomposition that is symmetrical and complementary to it. In some situations this alternative shows the temporal changes in within- and between-group selection more clearly than the Price equation. In addition, we provide a new perspective on strong vs. weak altruism by identifying their different underlying game structures (based on absolute fitness) and showing how their evolutionary dynamics are nevertheless similar under selection (based on relative fitness). In contrast to conventional wisdom, the model shows that both strong and weak altruism can evolve in periodically formed random groups of non-conditional strategies if groups are multigenerational. An integrative approach based on the NPD helps unify different perspectives on the evolution of altruism.}, } @article {pmid17059321, year = {2005}, author = {Boari, M}, title = {Fitness extraction and the conceptual foundations of political biology.}, journal = {Politics and the life sciences : the journal of the Association for Politics and the Life Sciences}, volume = {24}, number = {1-2}, pages = {64-75}, doi = {10.2990/1471-5457(2005)24[64:FEATCF]2.0.CO;2}, pmid = {17059321}, issn = {0730-9384}, abstract = {In well known formulations, political science, classical and neoclassical economics, and political economy have recognized as foundational a human impulse toward self-preservation. To employ this concept, modern social-sciences theorists have made simplifying assumptions about human nature and have then built elaborately upon their more incisive simplifications. Advances in biology, including advances in evolutionary theory, notably inclusive-fitness theory, have for decades now encouraged the reconsideration of such assumptions and, more ambitiously, the reconciliation of the social and life sciences. I ask if this reconciliation is feasible and test a path to the unification of politics and biology, called here "political biology." Two new notions, "fitness extraction" and "fitness exchange," are defined, then differentiated from each other, and lastly contrasted to cooperative gaming, the putative essential element of economics.}, } @article {pmid17046023, year = {2007}, author = {Ratnieks, FL and Helanterä, H and Foster, KR}, title = {Are mistakes inevitable? Sex allocation specialization by workers can reduce the genetic information needed to assess queen mating frequency.}, journal = {Journal of theoretical biology}, volume = {244}, number = {3}, pages = {470-477}, doi = {10.1016/j.jtbi.2006.09.003}, pmid = {17046023}, issn = {0022-5193}, mesh = {Alleles ; Animals ; Ants/genetics/*physiology ; Female ; Gene Expression ; Gene Frequency ; Genotype ; Male ; *Models, Genetic ; Odorants ; *Sex ; Sexual Behavior, Animal/*physiology ; }, abstract = {Insect workers can increase their inclusive fitness by biasing colony sex allocation towards males when their mother queen is mated to multiple males and females when she is singly mated. Workers need heritable variation in odour diversity to assess queen mating frequency. Here we present a simple one-locus two-allele model, which shows that the sex ratio specialization itself will often select against rare alleles that would provide additional information for the assessment of queen mating frequency. However, under certain rather restricted conditions, such as when sex ratios are highly female biased, and when worker reproduction is rare, sex ratio specialization can select for rare alleles. This suggests that sex allocation biasing by workers will usually reduce the very information that workers need to assess queen mating frequency. Our model is an example where an explicit treatment of underlying genetics and mechanisms of behaviour, such as information use, is necessary to fully understand the evolution of an adaptive behavioural strategy.}, } @article {pmid16979557, year = {2006}, author = {Hain, TJ and Neff, BD}, title = {Promiscuity drives self-referent kin recognition.}, journal = {Current biology : CB}, volume = {16}, number = {18}, pages = {1807-1811}, doi = {10.1016/j.cub.2006.07.021}, pmid = {16979557}, issn = {0960-9822}, mesh = {Animals ; Cues ; Fertilization in Vitro ; Larva/genetics/physiology ; Male ; Odorants ; Perciformes/genetics/*physiology ; Phenotype ; *Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {Kin selection theory has been one of the most significant advances in our understanding of social behavior . However, the discovery of widespread promiscuity has challenged the evolutionary importance of kin selection because it reduces the benefit associated with helping nestmates . This challenge would be resolved if promiscuous species evolved a self-referent kin-recognition mechanism that enables individuals to differentiate kin and nonkin . Here, we take advantage of an asymmetry in the level of promiscuity among males of alternative life histories in the bluegill sunfish (Lepomis macrochirus). We show that, as a consequence of this asymmetry, offspring of "parental" males have a high level of relatedness to nestmates, whereas offspring of "cuckolder" males have a low level of relatedness to nestmates. We find that offspring of parentals do not use a direct recognition mechanism to discriminate among nestmates, whereas offspring of cuckolders use kin recognition by self-referent phenotype matching to differentiate between kin and nonkin. Furthermore, we estimate that the cost of utilizing such self-referent kin recognition is equivalent to a relatedness (R) of at least 0.06. These results provide compelling evidence for adaptive use of kin recognition by self-referent phenotype matching and confirm the importance of kinship in social behavior.}, } @article {pmid16979546, year = {2006}, author = {Hauber, ME and Safran, RJ}, title = {Behavioural ecology: promiscuous fathers sire young that recognize true family.}, journal = {Current biology : CB}, volume = {16}, number = {18}, pages = {R797-800}, doi = {10.1016/j.cub.2006.08.036}, pmid = {16979546}, issn = {0960-9822}, mesh = {Animals ; Cues ; Female ; Male ; Perciformes/*physiology ; Phenotype ; *Sexual Behavior, Animal ; Social Behavior ; }, abstract = {Most theories of kin selection assume that animals are able to distinguish relatives from non-relatives. This is especially difficult in situations where mixed parentage precludes that relatedness is recognised by familiarity. Recent work shows that, within the same brood, young bluegill sunfish that are fathered by cuckolders--but not those sired by parental males--pick out their relatives using self-referent phenotype matching and not familiarity.}, } @article {pmid16968282, year = {2006}, author = {Temple, HJ and Hoffman, JI and Amos, W}, title = {Dispersal, philopatry and intergroup relatedness: fine-scale genetic structure in the white-breasted thrasher, Ramphocinclus brachyurus.}, journal = {Molecular ecology}, volume = {15}, number = {11}, pages = {3449-3458}, doi = {10.1111/j.1365-294X.2006.03006.x}, pmid = {16968282}, issn = {0962-1083}, mesh = {Animal Migration/*physiology ; Animals ; Conservation of Natural Resources ; DNA/chemistry/genetics ; Female ; Genetic Variation ; Genetics, Population ; Genotype ; Male ; Microsatellite Repeats/genetics ; Multivariate Analysis ; Passeriformes/genetics/*physiology ; Population Dynamics ; West Indies ; }, abstract = {Dispersal is a fundamental process influencing evolution, social behaviour, and the long-term persistence of populations. We use both observational and genetic data to investigate dispersal, kin-clustering and intergroup relatedness in the white-breasted thrasher, Ramphocinclus brachyurus, a cooperatively breeding bird that is globally endangered. Mark-resighting data suggested sex-biased dispersal, with females dispersing over greater distances while males remained philopatric. Accordingly, spatial autocorrelation analysis showed highly significant fine-scale genetic structure among males, but not among females. This fine-scale genetic structuring of the male population resulted in very high levels of relatedness between dominant males at neighbouring nests, similar to that seen within cooperative groups in many species where kin selection is cited as a cause of cooperation. By implication, between-group as well as within-group cooperation may be important, potentially creating a feedback loop in which short-distance dispersal by males leads to the formation of male kin clusters that in turn facilitate nepotistic interactions and favour further local recruitment. The strength of spatial autocorrelation, as measured by the autocorrelation coefficient, r, was approximately two to three times greater than that reported in previous studies of animals. Relatively short dispersal distances by both males and females may have a negative impact on the white-breasted thrasher's ability to colonize new areas, and may influence the long-term persistence of isolated populations. This should be taken into account when designating protected areas or selecting sites for habitat restoration.}, } @article {pmid16968260, year = {2006}, author = {Woxvold, IA and Adcock, GJ and Mulder, RA}, title = {Fine-scale genetic structure and dispersal in cooperatively breeding apostlebirds.}, journal = {Molecular ecology}, volume = {15}, number = {11}, pages = {3139-3146}, doi = {10.1111/j.1365-294X.2006.03009.x}, pmid = {16968260}, issn = {0962-1083}, mesh = {Animal Migration/*physiology ; Animals ; DNA/chemistry/genetics ; Female ; Genetic Variation/genetics ; Genetics, Population ; Male ; Microsatellite Repeats/genetics ; New South Wales ; Passeriformes/genetics/*physiology ; Polymerase Chain Reaction/veterinary ; Polymorphism, Genetic/genetics ; Reproduction/genetics/physiology ; Sequence Analysis, DNA ; }, abstract = {In cooperatively breeding species, restricted dispersal of offspring leads to clustering of closely related individuals, increasing the potential both for indirect genetic benefits and inbreeding costs. In apostlebirds (Struthidea cinerea), philopatry by both sexes results in the formation of large (up to 17 birds), predominantly sedentary breeding groups that remain stable throughout the year. We examined patterns of relatedness and fine-scale genetic structure within a population of apostlebirds using six polymorphic microsatellite loci. We found evidence of fine-scale genetic structure within the study population that is consistent with behavioural observations of short-distance dispersal, natal philopatry by both sexes and restricted movement of breeding groups between seasons. Global F(ST) values among breeding groups were significantly positive, and the average level of pairwise relatedness was significantly higher for individuals within groups than between groups. For individuals from different breeding groups, geographical distance was negatively correlated with pairwise relatedness and positively correlated with pairwise F(ST). However, when each sex was examined separately, this pattern was significant only among males, suggesting that females may disperse over longer distances. We discuss the potential for kin selection to influence the evolution and maintenance of cooperative breeding in apostlebirds. Our results demonstrate that spatial genetic structural analysis offers a useful alternative to field observations in examining dispersal patterns of cooperative breeders.}, } @article {pmid16953785, year = {2006}, author = {Spector, L and Klein, J}, title = {Genetic stability and territorial structure facilitate the evolution of tag-mediated altruism.}, journal = {Artificial life}, volume = {12}, number = {4}, pages = {553-560}, doi = {10.1162/artl.2006.12.4.553}, pmid = {16953785}, issn = {1064-5462}, mesh = {*Altruism ; Animals ; Artificial Intelligence ; *Biological Evolution ; Computer Simulation ; Genomic Instability ; Humans ; Models, Genetic ; Models, Psychological ; }, abstract = {Evolutionary theorists have long been interested in the conditions that permit the evolution of altruistic cooperation. Recent work has demonstrated that altruistic donation can evolve in surprisingly simple models, in which agents base their decisions to donate solely on the similarity of evolved "tags" relative to evolved tag-difference tolerances. There is disagreement, however, about the conditions under which tag-mediated altruism will in fact evolve. Here we vary two critical parameters in a standard model of tag-mediated altruism-genetic stability and territorial structure-and show that altruism evolves in a wide range of conditions. We demonstrate the evolution of significant levels of altruism even when the immediate costs to donors equal the benefits to recipients. We describe the mechanism that permits the emergence of altruism in the model as a form of kin selection that is facilitated by interactions between altruism, genetic drift, and fecundity.}, } @article {pmid16951902, year = {2006}, author = {Libertini, G}, title = {Evolutionary explanations of the "actuarial senescence in the wild" and of the "state of senility".}, journal = {TheScientificWorldJournal}, volume = {6}, number = {}, pages = {1086-1108}, doi = {10.1100/tsw.2006.209}, pmid = {16951902}, issn = {1537-744X}, mesh = {Aging/*genetics ; Animals ; Animals, Wild/physiology ; Apoptosis/physiology ; *Biological Evolution ; Humans ; Models, Biological ; Selection, Genetic ; Telomere/physiology ; }, abstract = {A large set of data suggests that progressive reduction of fitness and senile decay in vertebrates are in correlation with the decline of cell replication capacities. However, the limits in such capacities are hardly explained in evolutionarily terms by current gerontological theories that rule out fitness decline as something genetically determined and regulated, and therefore somehow favored by natural selection. Four theories are tested as possible explanations of the "increasing mortality with increasing chronological age in populations in the wild" ("IMICAW"[1]), alias "actuarial senescence in the wild"[2], and of the observed negative correlation between extrinsic mortality and the ratio between deaths due to intrinsic mortality and deaths due to extrinsic mortality. Only the theory attributing an adaptive value to IMICAW allows an evolutionary explanation for it and for the aforesaid inverse correlation, while the other three theories ("mutation accumulation", "antagonistic pleiotropy", and "disposable soma" th.) even predict a positive correlation. Afterwards, the same theories are tested as possible explanations for the "state of senility"[3], namely the deteriorated state of individuals in artificially protected conditions (captivity, civilization, etc.) at ages rarely or never observable in the wild. With the distinction between "damage resulting from intrinsic living processes"[4], alias "age changes"[5], and "age-associated diseases"[4,5], the same theory explaining IMICAW allows a rational interpretation of the first category of phenomena while another theory, the "mutation accumulation" hypothesis, gives an immediate interpretation for the second category. The current gerontological paradigm explaining the increasing mortality with increasing chronological age as consequence of insufficient selection should be restricted to the "age-associated diseases". For IMICAW, it should be substituted with the concept of a physiologic phenomenon genetically determined by a balance of opposite selective pressures--strictly in terms of kin selection--and, for "age changes", with the action of the same IMICAW-causing mechanisms at ages when selection becomes ineffective.}, } @article {pmid16942818, year = {2006}, author = {Fletcher, JA and Zwick, M and Doebeli, M and Wilson, DS}, title = {What's wrong with inclusive fitness?.}, journal = {Trends in ecology & evolution}, volume = {21}, number = {11}, pages = {597-8; author reply 599-600}, doi = {10.1016/j.tree.2006.08.008}, pmid = {16942818}, issn = {0169-5347}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; *Biological Evolution ; Insecta/*genetics ; Models, Biological ; *Selection, Genetic ; }, } @article {pmid16928642, year = {2006}, author = {Lizé, A and Carval, D and Cortesero, AM and Fournet, S and Poinsot, D}, title = {Kin discrimination and altruism in the larvae of a solitary insect.}, journal = {Proceedings. Biological sciences}, volume = {273}, number = {1599}, pages = {2381-2386}, pmid = {16928642}, issn = {0962-8452}, mesh = {*Altruism ; Animals ; Coleoptera/*physiology ; Feeding Behavior/*physiology ; Larva/physiology ; Species Specificity ; }, abstract = {Kin selection theory predicts altruism between related individuals, which requires the ability to recognize kin from non-kin. In insects, kin discrimination associated with altruistic behaviour is well-known in clonal and social species but in very few solitary insects. Here, we report that the solitary larvae of a non-social insect Aleochara bilineata Gyll. (Coleoptera; Staphylinidae) show kin discrimination and sibling-directed altruistic behaviour. Larvae superparasitize more frequently the hosts parasitized by non-kin individuals than those hosts parasitized by siblings. Kin discrimination probably occurs by self-referent phenotype matching, where an individual compares its own phenotype with that of a non-familiar related individual, a mechanism rarely demonstrated in animals. The label used to recognize kin from non-kin corresponds to substances contained in the plug placed on the hosts by the resident larvae during the parasitization process. Kin competition induced by a limited larval dispersion may have favoured the evolution of kin recognition in this solitary species.}, } @article {pmid16874634, year = {2006}, author = {Fletcher, JA and Zwick, M}, title = {Unifying the theories of inclusive fitness and reciprocal altruism.}, journal = {The American naturalist}, volume = {168}, number = {2}, pages = {252-262}, doi = {10.1086/506529}, pmid = {16874634}, issn = {1537-5323}, mesh = {*Altruism ; *Biological Evolution ; Models, Biological ; }, abstract = {Inclusive fitness and reciprocal altruism are widely thought to be distinct explanations for how altruism evolves. Here we show that they rely on the same underlying mechanism. We demonstrate this commonality by applying Hamilton's rule, normally associated with inclusive fitness, to two simple models of reciprocal altruism: one, an iterated prisoner's dilemma model with conditional behavior; the other, a mutualistic symbiosis model where two interacting species differ in conditional behaviors, fitness benefits, and costs. We employ Queller's generalization of Hamilton's rule because the traditional version of this rule does not apply when genotype and phenotype frequencies differ or when fitness effects are nonadditive, both of which are true in classic models of reciprocal altruism. Queller's equation is more general in that it applies to all situations covered by earlier versions of Hamilton's rule but also handles nonadditivity, conditional behavior, and lack of genetic similarity between altruists and recipients. Our results suggest changes to standard interpretations of Hamilton's rule that focus on kinship and indirect fitness. Despite being more than 20 years old, Queller's generalization of Hamilton's rule is not sufficiently appreciated, especially its implications for the unification of the theories of inclusive fitness and reciprocal altruism.}, } @article {pmid16872637, year = {2006}, author = {Janssen, MA and Goldstone, RL}, title = {Dynamic-persistence of cooperation in public good games when group size is dynamic.}, journal = {Journal of theoretical biology}, volume = {243}, number = {1}, pages = {134-142}, doi = {10.1016/j.jtbi.2006.06.012}, pmid = {16872637}, issn = {0022-5193}, mesh = {Animals ; Biological Evolution ; *Cooperative Behavior ; *Game Theory ; Group Processes ; *Models, Biological ; Mutation ; Population Density ; *Population Dynamics ; }, abstract = {The evolution of cooperation is possible with a simple model of a population of agents that can move between groups. The agents play public good games within their group. The relative fitness of individuals within the whole population affects their number of offspring. Groups of cooperators evolve but over time are invaded by defectors which eventually results in the group's extinction. However, for small levels of migration and mutation, high levels of cooperation evolve at the population level. Thus, evolution of cooperation based on individual fitness without kin selection, indirect or direct reciprocity is possible. We provide an analysis of the parameters that affect cooperation, and describe the dynamics and distribution of population sizes over time.}, } @article {pmid16866635, year = {2007}, author = {Schwarz, MP and Richards, MH and Danforth, BN}, title = {Changing paradigms in insect social evolution: insights from halictine and allodapine bees.}, journal = {Annual review of entomology}, volume = {52}, number = {}, pages = {127-150}, doi = {10.1146/annurev.ento.51.110104.150950}, pmid = {16866635}, issn = {0066-4170}, mesh = {Animals ; *Bees ; *Biological Evolution ; Climate ; Reproduction ; *Social Behavior ; }, abstract = {Until the 1980s theories of social insect evolution drew strongly on halictine and allodapine bees. However, that early work suffered from a lack of sound phylogenetic inference and detailed information on social behavior in many critical taxa. Recent studies have changed our understanding of these bee groups in profound ways. It has become apparent that forms of social organization, caste determination, and sex allocation are more labile and complex than previously thought, although the terminologies for describing them are still inadequate. Furthermore, the unexpected complexity means that many key parameters in kin selection and reproductive skew models remain unquantified, and addressing this lack of information will be formidable. At the same time, phylogenetic questions have become more tractable, and DNA sequence-based studies have resolved questions that earlier studies could not resolve, radically changing our understanding of the number of origins and losses of sociality in these bees.}, } @article {pmid16859334, year = {2001}, author = {Brigandt, I}, title = {The homeopathy of kin selection: an evaluation of Van den Berghe's sociobiological approach to ethnic nepotism.}, journal = {Politics and the life sciences : the journal of the Association for Politics and the Life Sciences}, volume = {20}, number = {2}, pages = {203-215}, doi = {10.1017/s0730938400005487}, pmid = {16859334}, issn = {0730-9384}, abstract = {The present discussion of sociobiological approaches to ethnic nepotism takes Pierre van den Berghe's theory as a starting point. Two points, which have not been addressed in former analyses, are considered to be of particular importance. It is argued that the behavioral mechanism of ethnic nepotism -- as understood by van den Berghe -- cannot explain ethnic boundaries and attitudes. In addition, I show that van den Berghe's central premise concerning ethnic nepotism is in contradiction to Hamilton's formula, the essential principle of kin selection theory. It is further discussed how other approaches that make reference to ethnic nepotism are related to van den Berghe's account and its problems. I conclude with remarks on the evolutionary explanation of ethnic phenomena.}, } @article {pmid16846912, year = {2006}, author = {Holzer, B and Kümmerli, R and Keller, L and Chapuisat, M}, title = {Sham nepotism as a result of intrinsic differences in brood viability in ants.}, journal = {Proceedings. Biological sciences}, volume = {273}, number = {1597}, pages = {2049-2052}, pmid = {16846912}, issn = {0962-8452}, mesh = {Animals ; Ants/genetics/*physiology ; *Behavior, Animal ; Genotype ; *Social Behavior ; }, abstract = {In animal societies, cooperation for the common wealth and latent conflicts due to the selfish interests of individuals are in delicate balance. In many ant species, colonies contain multiple breeders and workers interact with nestmates of varying degrees of relatedness. Therefore, workers could increase their inclusive fitness by preferentially caring for their closest relatives, yet evidence for nepotism in insect societies remains scarce and controversial. We experimentally demonstrate that workers of the ant Formica exsecta do not discriminate between highly related and unrelated brood, but that brood viability differs between queens. We further show that differences in brood viability are sufficient to explain a relatedness pattern that has previously been interpreted as evidence for nepotism. Hence, our findings support the view that nepotism remains elusive in social insects and emphasize the need for further controlled experiments.}, } @article {pmid16842425, year = {2006}, author = {Pomilla, C and Rosenbaum, HC}, title = {Estimates of relatedness in groups of humpback whales (Megaptera novaeangliae) on two wintering grounds of the Southern Hemisphere.}, journal = {Molecular ecology}, volume = {15}, number = {9}, pages = {2541-2555}, doi = {10.1111/j.1365-294X.2006.02943.x}, pmid = {16842425}, issn = {0962-1083}, mesh = {Animals ; Cold Temperature ; Female ; Gabon ; Genetic Variation/genetics ; Genotype ; Humpback Whale/*genetics/*physiology ; Madagascar ; Male ; Microsatellite Repeats ; Mothers ; *Pedigree ; Population Dynamics ; *Seasons ; }, abstract = {Group formation in humpback whales has been described in relation to different components of the migratory cycle, yet it is debated whether such groups represent real social bonding or ephemeral aggregations. Cooperative behaviours are exhibited during feeding activities, and it has been suggested that males may cooperate during competition for mates. Since most cooperative behaviours are expected to originate among kin, genetic relatedness represents a critical variable in the understanding of any social phenomenon, especially when cooperation cannot be confirmed unequivocally. Using an approach combining multi-locus microsatellite genotyping and several genetic relatedness estimators, we analyzed whale associations for two different wintering grounds in the Southern Hemisphere. The analyses included 648 whales sampled from 292 groups off the coast of Gabon and Northeast Madagascar, and screened for eleven microsatellite loci. Through simulations, we assessed the performance of three pairwise relatedness estimators. The individuals were molecularly sexed and their associations were investigated in the context of sex and group type. No significant association among relatives was found with the exception of mother-offspring pairs, supporting previous indications of extended maternal care. The analysis from the Gabon population also suggests that related males may avoid each other during competitive activities. Our results demonstrate that if cooperative behaviours occur on wintering grounds they are not favoured by kin selection.}, } @article {pmid16781823, year = {2006}, author = {Montañés-Rada, F and Ramírez, JM and De Lucas Taracena, MT}, title = {Violence in mental disorders and community sample: an evolutionary model related with dominance in social relationships.}, journal = {Medical hypotheses}, volume = {67}, number = {4}, pages = {930-940}, doi = {10.1016/j.mehy.2006.02.054}, pmid = {16781823}, issn = {0306-9877}, mesh = {Adult ; Female ; Humans ; Male ; Mental Disorders/diagnosis/*genetics/*psychology ; Models, Genetic ; Prevalence ; *Social Dominance ; *Social Environment ; *Violence ; }, abstract = {The major risk determinants of violence are to be young and male, to have low socioeconomic status and suffering substance abuse. This is true whether it occurs in the context of a concurrent mental illness or not; i.e., mental disorders are neither necessary, nor sufficient causes for violence. Intense motivation is a facilitating factor for violence in clinical and non clinical samples. This explains why 'normal' people, are implicated in planned violence at higher rates than mentally ill (e.g. in criminal acts against property). However mentally ill patients are more easily implicated in impulsive violence or in violence without obvious cause due to veiled motivation fuelled by unidentified symptoms. Subjective or real awareness of competitive disadvantage increases motivation for violence (e.g. paranoid, narcissistic symptoms, etc.). Many psychiatric disorders as antisocial disorder, borderline, schizophrenia, have most of the factors that facilitate the appearance of violence. Antisocial disorder is a good model to study determinants of violence in normal samples as it is present in young males that do not have any psychotic symptom, have stable symptomatology, self control under scrutiny, and their motivations are similar to normal samples. Our evolutionary model suggests that there is a non random association of genetic factors (genes, pseudogenes, promoting areas, etc.), that is, a genetic cluster (cluster DO), whose phylogenetic function is to motivate to be the dominant in social relationships. To be the dominant is a major psychological feature present in many social groups of animals, included primates. DO cluster have sense from an evolutionary viewpoint: when expressed in no pathological way it increases inclusive fitness (transmission of the genes of a person genotype whether by oneself or by relatives reproduction). Features of cluster DO in humans are expressed differently according to sex, age, moral education, level of intelligence, etc. Cluster DO has higher phenotypical expression in males and young people. Primary antisocial personality disorder and other related disorders (cluster B personality disorders, disocial, defiant disorder, etc.), are a pathological manifestation of this cluster DO. Some other genetic clusters that causes the genetic liability to some disorders (e.g. attention deficit disorder) are non random associated with cluster DO, thus explaining clinical comorbidity. According to our model, motivation for dominance usually prevails over motivation for material benefit or antinormative behaviour, this explains some incongruent behaviour in antisocial patients not elucidated by other models. Along with the primary expressed feature of dominance of cluster DO there are other secondary features that have been identified by psychobiological studies: novelty seeking, intolerance for frustration, impulsiveness, fearless, aggressiveness, higher threshold for activation of the sympathetic system, lack of empathy, egoism, non acceptance of rules, defiant and rebellious behaviour, manipulation in social interactions, selfishness and deficits in altruism or in social co-operation.}, } @article {pmid16779946, year = {2005}, author = {Bernard, LC and Mills, M and Swenson, L and Walsh, RP}, title = {An evolutionary theory of human motivation.}, journal = {Genetic, social, and general psychology monographs}, volume = {131}, number = {2}, pages = {129-184}, doi = {10.3200/MONO.131.2.129-184}, pmid = {16779946}, issn = {8756-7547}, mesh = {*Biological Evolution ; Cognition ; Consciousness ; Emotions ; Humans ; Learning ; *Motivation ; *Psychological Theory ; Social Behavior ; }, abstract = {The authors review psychology's historical, competing perspectives on human motivation and propose a new comprehensive theory. The new theory is based on evolutionary principles as proposed by C. Darwin (1859) and modified by W. D. Hamilton (1964, 1996), R. L. Trivers (1971, 1972), and R. Dawkins (1989). The theory unifies biological, behavioral, and cognitive approaches to motivation. The theory is neuropsychological and addresses conscious and nonconscious processes that underlie motivation, emotion, and self-control. The theory predicts a hierarchical structure of motives that are measurable as individual differences in human behavior. These motives are related to social problem domains (D. B. Bugental, 2000; D. T. Kenrick, N. P. Li, & J. Butner, 2003), and each is hypothesized to solve a particular problem of human inclusive fitness.}, } @article {pmid16777741, year = {2006}, author = {Killingback, T and Bieri, J and Flatt, T}, title = {Evolution in group-structured populations can resolve the tragedy of the commons.}, journal = {Proceedings. Biological sciences}, volume = {273}, number = {1593}, pages = {1477-1481}, pmid = {16777741}, issn = {0962-8452}, mesh = {Animals ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Game Theory ; Models, Biological ; Population Dynamics ; }, abstract = {Public goods are the key features of all human societies and are also important in many animal societies. Collaborative hunting and collective defence are but two examples of public goods that have played a crucial role in the development of human societies and still play an important role in many animal societies. Public goods allow societies composed largely of cooperators to outperform societies composed mainly of non-cooperators. However, public goods also provide an incentive for individuals to be selfish by benefiting from the public good without contributing to it. This is the essential paradox of cooperation-known variously as the Tragedy of the Commons, Multi-person Prisoner's Dilemma or Social Dilemma. Here, we show that a new model for evolution in group-structured populations provides a simple and effective mechanism for the emergence and maintenance of cooperation in such a social dilemma. This model does not depend on kin selection, direct or indirect reciprocity, punishment, optional participation or trait-group selection. Since this mechanism depends only on population dynamics and requires no cognitive abilities on the part of the agents concerned, it potentially applies to organisms at all levels of complexity.}, } @article {pmid16769087, year = {2006}, author = {van Veelen, M}, title = {Why kin and group selection models may not be enough to explain human other-regarding behaviour.}, journal = {Journal of theoretical biology}, volume = {242}, number = {3}, pages = {790-797}, doi = {10.1016/j.jtbi.2006.04.022}, pmid = {16769087}, issn = {0022-5193}, mesh = {*Altruism ; *Family ; Humans ; *Models, Genetic ; Phenotype ; *Selection, Genetic ; }, abstract = {Models of kin or group selection usually feature only one possible fitness transfer. The phenotypes are either to make this transfer or not to make it and for any given fitness transfer, Hamilton's rule predicts which of the two phenotypes will spread. In this article we allow for the possibility that different individuals or different generations face similar, but not necessarily identical possibilities for fitness transfers. In this setting, phenotypes are preference relations, which concisely specify behaviour for a range of possible fitness transfers (rather than being a specification for only one particular situation an animal or human can be in). For this more general set-up, we find that only preference relations that are linear in fitnesses can be explained using models of kin selection and that the same applies to a large class of group selection models. This provides a new implication of hierarchical selection models that could in principle falsify them, even if relatedness--or a parameter for assortativeness--is unknown. The empirical evidence for humans suggests that hierarchical selection models alone are not enough to explain their other-regarding or altruistic behaviour.}, } @article {pmid16765385, year = {2006}, author = {Wilkins, JF}, title = {Competitive signal discrimination, methylation reprogramming and genomic imprinting.}, journal = {Journal of theoretical biology}, volume = {242}, number = {3}, pages = {643-651}, doi = {10.1016/j.jtbi.2006.04.015}, pmid = {16765385}, issn = {0022-5193}, mesh = {Alleles ; Animals ; *Computer Simulation ; *DNA Methylation ; Embryonic Development ; Female ; *Gene Expression Regulation, Developmental ; *Genomic Imprinting ; Humans ; Male ; Mammals/*embryology ; *Models, Genetic ; Pregnancy ; }, abstract = {Genomic imprinting (parent-of-origin-dependent gene regulation) is associated with intra-genomic evolutionary conflict over the optimal pattern of gene expression. Most theoretical models of imprinting focus on the conflict between the maternally and paternally derived alleles at an imprinted locus. Recently, however, more attention has been focused on multi-directional conflicts involving not only the imprinted gene itself, but also the genes that encode the regulatory machinery responsible for establishing and maintaining imprinted gene expression. In this paper, I examine the conflict involved in epigenetic reprogramming of imprinted genes in early mammalian embryonic development. In the earliest phase of development, maternal-store proteins are responsible for most regulatory activity in the embryo. These proteins are under selection to maximize the mother's inclusive fitness, which is not identical to that of either of the sets of genes present in the embryo. Both the maternally and paternally derived genomes in the embryo favor maintenance of the epigenetic modifications established in the female and male germlines, respectively. Maternal-store proteins favor maintenance of some of these modifications, but erasure of others. Here I consider the logical structure of the machinery responsible for these two activities. Methylation maintenance is most effectively performed by AND-linked architectures, which may explain the unusual trafficking behavior of the oocyte-specific DNA methyltransferase, Dnmt1o. By contrast, demethylation is better supported by OR-linked architectures, which may explain the difficulty in identifying the factor(s) responsible for the active demethylation of the paternal genome following fertilization.}, } @article {pmid16739021, year = {2006}, author = {Dronnet, S and Lohou, C and Christides, JP and Bagnères, AG}, title = {Cuticular hydrocarbon composition reflects genetic relationship among colonies of the introduced termite Reticulitermes santonensis feytaud.}, journal = {Journal of chemical ecology}, volume = {32}, number = {5}, pages = {1027-1042}, pmid = {16739021}, issn = {0098-0331}, mesh = {Aggression/physiology ; Animals ; Chromatography, Gas ; Environment ; Genetic Variation ; Genotype ; Hydrocarbons/*analysis ; Isoptera/chemistry/*genetics/physiology ; Lipids/analysis ; Microsatellite Repeats ; Paris ; Principal Component Analysis ; }, abstract = {Nestmate recognition plays a key role in kin selection to maintain colony integrity in social insects. Previous studies have demonstrated that nestmate recognition is dependent on detection of cuticular hydrocarbons. However, the absence of intraspecific aggression between some colonies of Isoptera and social Hymenoptera questions whether kin recognition must occur in social insects. The purpose of this study was to determine if cuticular hydrocarbon similarity and high genetic relatedness could explain the lack of intraspecific aggression among and within colonies of the introduced subterranean termite Reticulitermes santonensis. We performed both GC analysis of cuticular hydrocarbons and genotyping by using 10 DNA microsatellite loci on the same 10 workers from each of 14 parisian colonies. Multivariate analyses demonstrated correspondence between cuticular hydrocarbon patterns and genetic variation. By using a redundancy analysis combining chemical and genetic data, we found that a few hydrocarbons (mainly short vs. long chains; saturated vs. unsaturated alkanes) were associated with most genetic variation. We also found a strong positive correlation between chemical and genetic distances between colonies, thus providing evidence of a genetic basis for cuticular hydrocarbon variation. However, genetic distance did not account for all chemical variation, thus suggesting that some hydrocarbon variation was environmentally derived. Investigation at the intracolony level indicated that cuticular hydrocarbons did not depend on colony social structure. Based on our findings, we speculate that the absence of intraspecific aggression in R. santonensis may result from a loss of diversity in genetically derived recognition compounds in this species that presumably descended from R. flavipes populations imported from North America.}, } @article {pmid16701471, year = {2006}, author = {Foster, KR and Wenseleers, T and Ratnieks, FL}, title = {Kin selection is the key to altruism.}, journal = {Trends in ecology & evolution}, volume = {21}, number = {2}, pages = {57-60}, doi = {10.1016/j.tree.2005.11.020}, pmid = {16701471}, issn = {0169-5347}, mesh = {*Altruism ; Animals ; *Behavior, Animal ; *Biological Evolution ; Hymenoptera/genetics/physiology ; Models, Biological ; *Selection, Genetic ; }, abstract = {Kin selection theory, also known as inclusive fitness theory, has been the subject of much debate and misunderstanding. Nevertheless, the idea that relatedness among individuals can drive the evolution of altruism has emerged as a central paradigm in evolutionary biology. Or has it? In two recent articles, E.O. Wilson argues that kin selection should no longer be considered the main explanation for the evolution of altruism in insect societies. Here, we discuss what these articles say about kin selection and how it relates to the theory. We conclude that kin selection remains the key explanation for the evolution of altruism in eusocial insects.}, } @article {pmid16688175, year = {2006}, author = {Field, J and Cronin, A and Bridge, C}, title = {Future fitness and helping in social queues.}, journal = {Nature}, volume = {441}, number = {7090}, pages = {214-217}, doi = {10.1038/nature04560}, pmid = {16688175}, issn = {1476-4687}, mesh = {Animals ; Female ; Male ; Population Density ; Reproduction/physiology ; *Social Behavior ; Social Dominance ; Wasps/*physiology ; }, abstract = {Helpers in primitively eusocial and cooperatively breeding animal societies forfeit their own reproduction to rear the offspring of a queen or breeding pair, but may eventually attain breeding status themselves. Kin selection provides a widely accepted theoretical framework for understanding these societies, but differences in genetic relatedness do not explain a universal societal feature: the huge variation between individuals in helping effort. An alternative explanation for this variation lies in a fundamental trade-off faced by helpers: by working harder, they increase the indirect component of their fitness, but simultaneously decrease their own future survival and fecundity. Here, we show that individuals work less hard when they stand to lose more future fitness through working. We experimentally manipulated two components of future fitness in social queues of hover wasps (Stenogastrinae): a helper's chance of inheriting an egg-laying position, and the workforce available to rear her offspring should she inherit. After each manipulation, helpers increased or decreased their effort as appropriate to the change in expected future fitness that they experienced. Although helping provides significant indirect fitness benefits for hover wasps, our study shows that variation in the costs associated with helping is the major determinant of helping effort.}, } @article {pmid16676159, year = {2006}, author = {Kronauer, DJ and Berghoff, SM and Powell, S and Denny, AJ and Edwards, KJ and Franks, NR and Boomsma, JJ}, title = {A reassessment of the mating system characteristics of the army ant Eciton burchellii.}, journal = {Die Naturwissenschaften}, volume = {93}, number = {8}, pages = {402-406}, pmid = {16676159}, issn = {0028-1042}, mesh = {Animals ; Ants/genetics/*physiology ; Female ; Male ; Microsatellite Repeats ; Reproduction/*physiology ; Sexual Behavior, Animal ; Software ; }, abstract = {In a recent study, Denny et al. (2004a) showed that queens of the army ant, Eciton burchellii, mate with multiple males and presented estimates suggesting that they mate with more males than queens of any other ant species so far investigated. They also inferred that data were consistent with queens being inseminated repeatedly throughout their life, which would be exceptional among the social Hymenoptera and contradictory to predictions from kin selection theory. In the present study, we reanalyze these data using new software and supplement them with similar microsatellite data from other colonies of the same species. Mating frequencies in E. burchellii are indeed very high (mean observed and effective queen-mating frequencies of 12.9 each) but considerably lower than the previous estimates. We show that the number of patrilines represented in the first worker offspring of a young queen is lower than in older queens but suggest that this may be due to initial sperm clumping in the queen's sperm storage organ, rather than to repeated inseminations. Moreover, we found no evidence for repeated mating by genotyping sequential worker generations produced by a single old queen, showing that she did not obtain new inseminations despite ample opportunities for mating.}, } @article {pmid16670991, year = {2006}, author = {Nonacs, P and Liebert, AE and Starks, PT}, title = {Transactional skew and assured fitness return models fail to predict patterns of cooperation in wasps.}, journal = {The American naturalist}, volume = {167}, number = {4}, pages = {467-480}, doi = {10.1086/501168}, pmid = {16670991}, issn = {1537-5323}, mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; *Cooperative Behavior ; Female ; Male ; Models, Biological ; Reproduction ; Wasps/*physiology ; }, abstract = {Cooperative breeders often exhibit reproductive skew, where dominant individuals reproduce more than subordinates. Two approaches derived from Hamilton's inclusive fitness model predict when subordinate behavior is favored over living solitarily. The assured fitness return (AFR) model predicts that subordinates help when they are highly likely to gain immediate indirect fitness. Transactional skew models predict dominants and subordinates "agree" on a level of reproductive skew that induces subordinates to join groups. We show the AFR model to be a special case of transactional skew models that assumes no direct reproduction by subordinates. We use data from 11 populations of four wasp species (Polistes, Liostenogaster) as a test of whether transactional frameworks suffice to predict when subordinate behavior should be observed in general and the specific level of skew observed in cooperative groups. The general prediction is supported; in 10 of 11 cases, transactional models correctly predict presence or absence of cooperation. In contrast, the specific prediction is not consistent with the data. Where cooperation occurs, the model accurately predicts highly biased reproductive skew between full sisters. However, the model also predicts that distantly related or unrelated females should cooperate with low skew. This prediction fails: cooperation with high skew is the observed norm. Neither the generalized transactional model nor the special-case AFR model can explain this significant feature of wasp sociobiology. Alternative, nontransactional hypotheses such as parental manipulation and kin recognition errors are discussed.}, } @article {pmid16637492, year = {2006}, author = {Kokko, H and Ots, I}, title = {When not to avoid inbreeding.}, journal = {Evolution; international journal of organic evolution}, volume = {60}, number = {3}, pages = {467-475}, pmid = {16637492}, issn = {0014-3820}, mesh = {Animals ; Biological Evolution ; Female ; *Inbreeding ; Male ; *Models, Biological ; }, abstract = {Avoidance of incestuous matings is widely reported across many animal taxa, and the adaptive value of such behavior is explained through inbreeding depression. However, an old and somewhat neglected theoretical result predicts that inbred matings offer another, positive effect on the inclusive fitness of parents: an individual who mates with a relative will help that relative to spread genes identical by descent. This benefit can be substantial, if the additional mating achieved by the relative does not harm his mating success otherwise, and in the context of selfing in plants the phenomenon is well known. Here, we develop a model that derives expected values of inbreeding tolerance, that is, the magnitude of inbreeding depression that is required to make individuals avoid inbreeding, for different animal life histories and parental investment patterns. We also distinguish between simultaneous and sequential mate choice, and show that inbreeding tolerance should often be remarkably high in the latter scenario in particular, although egalitarian parental care will lead to lower tolerance. There is a mismatch between theory and data: the almost complete lack of cases where individuals prefer to mate incestuously is at odds with a large overlap between the predicted range of inbreeding tolerance and estimates of inbreeding depression found in nature. We discuss four different solutions to this enigma, and suggest that inbreeding tolerance, where it is found, should not always be attributed to a simple constraint that has prevented finding any other mate.}, } @article {pmid16625195, year = {2006}, author = {Burtsev, M and Turchin, P}, title = {Evolution of cooperative strategies from first principles.}, journal = {Nature}, volume = {440}, number = {7087}, pages = {1041-1044}, doi = {10.1038/nature04470}, pmid = {16625195}, issn = {1476-4687}, mesh = {Animals ; *Biological Evolution ; Birds/*physiology ; Computer Simulation ; *Cooperative Behavior ; Models, Biological ; Population Density ; Time Factors ; }, abstract = {One of the greatest challenges in the modern biological and social sciences is to understand the evolution of cooperative behaviour. General outlines of the answer to this puzzle are currently emerging as a result of developments in the theories of kin selection, reciprocity, multilevel selection and cultural group selection. The main conceptual tool used in probing the logical coherence of proposed explanations has been game theory, including both analytical models and agent-based simulations. The game-theoretic approach yields clear-cut results but assumes, as a rule, a simple structure of payoffs and a small set of possible strategies. Here we propose a more stringent test of the theory by developing a computer model with a considerably extended spectrum of possible strategies. In our model, agents are endowed with a limited set of receptors, a set of elementary actions and a neural net in between. Behavioural strategies are not predetermined; instead, the process of evolution constructs and reconstructs them from elementary actions. Two new strategies of cooperative attack and defence emerge in simulations, as well as the well-known dove, hawk and bourgeois strategies. Our results indicate that cooperative strategies can evolve even under such minimalist assumptions, provided that agents are capable of perceiving heritable external markers of other agents.}, } @article {pmid16599973, year = {2006}, author = {Kronauer, DJ and Schöning, C and Boomsma, JJ}, title = {Male parentage in army ants.}, journal = {Molecular ecology}, volume = {15}, number = {4}, pages = {1147-1151}, doi = {10.1111/j.1365-294X.2005.02850.x}, pmid = {16599973}, issn = {0962-1083}, mesh = {Alleles ; Animals ; Ants/*genetics/physiology ; Genotype ; Male ; Microsatellite Repeats/genetics ; *Sexual Behavior, Animal ; }, abstract = {In most social insects workers do not mate, but have retained the ability to produce haploid eggs that can develop into viable male offspring. Under what circumstances this reproductive potential is realized and how the ensuing worker-queen conflict over male production is resolved, is an area of active research in insect sociobiology. Here we present microsatellite data for 176 males from eight colonies of the African army ant Dorylus (Anomma) molestus. Comparison with worker genotypes and inferred queen genotypes from the same colonies show that workers do not or at best very rarely reproduce in the presence of the queen. Queens of D. (A.) molestus are known to be highly multiply mated. This implies that workers are on average more closely related to queen sons than to other workers' sons, so that our results are consistent with predictions from inclusive fitness theory. It remains unknown, however, whether worker sterility is maintained by active worker policing or by self-restraint.}, } @article {pmid16599972, year = {2006}, author = {Halverson, MA and Skelly, DK and Caccone, A}, title = {Kin distribution of amphibian larvae in the wild.}, journal = {Molecular ecology}, volume = {15}, number = {4}, pages = {1139-1145}, doi = {10.1111/j.1365-294X.2006.02819.x}, pmid = {16599972}, issn = {0962-1083}, mesh = {Alleles ; *Animal Migration ; Animals ; Fresh Water ; Genetic Carrier Screening ; Larva/genetics/growth & development ; Microsatellite Repeats/genetics ; Ranidae/*genetics/*growth & development ; Selection, Genetic ; *Siblings ; }, abstract = {According to kin selection theory, the location of an individual with respect to its relatives can have important ramifications for its fitness. Perhaps more than any other vertebrate group, anuran amphibian larvae have been the subject of many experiments on this topic. Some anuran species have been shown in the laboratory to recognize and associate with their siblings and half-siblings. However, due to the difficulty of identifying sibships, no kinship studies with anuran larvae have been conducted in the wild. Here, we use microsatellite analysis to show that wood frog (Rana sylvatica) tadpoles were nonrandomly distributed in two ponds with respect to their relatives. In one pond, the tadpoles were significantly clumped with their siblings or half-siblings as expected from other published laboratory studies on this species. However, in another pond, the tadpoles were significantly nonrandomly dispersed from their siblings or half-siblings. This is the first example of kin repulsion of nonreproductive animals in the wild and the first time a species has been shown to display both aggregation and repulsion under different circumstances. These results suggest that kin distribution is context dependent and demonstrate the importance of testing kin selection hypotheses under natural conditions.}, } @article {pmid16580787, year = {2006}, author = {Yun, AJ and Lee, PY and Doux, J}, title = {Osteoarthritis: an example of phenoptosis through autonomic dysfunction?.}, journal = {Medical hypotheses}, volume = {67}, number = {5}, pages = {1079-1085}, doi = {10.1016/j.mehy.2006.02.026}, pmid = {16580787}, issn = {1532-2777}, mesh = {Apoptosis ; Autonomic Nervous System/pathology/*physiopathology ; Biomechanical Phenomena ; Cartilage/pathology/physiopathology ; Cell Death/physiology ; Homeostasis ; Humans ; Joints/pathology/physiopathology ; Models, Biological ; Osteoarthritis/pathology/*physiopathology ; }, abstract = {Phenoptosis, the programmed death of organisms akin to cellular apoptosis, constitutes a type of Darwinian selection that enhances inclusive fitness. It provides a means by which senescent and pre-senescent members can self-terminate if they have incurred sufficient cumulative stress such that their continued survival detracts from inclusive fitness. Sepsis, vascular disease, menopause, cancer, and aging all represent examples of phenoptosis at work. We previously proposed that feed-forward autonomic dysfunction fundamentally drives phenoptosis in all its guises. Accordingly, we now postulate that osteoarthritis defines a type of biomechanical phenoptosis, mediated by feed-forward autonomic dysfunction, and manifested through joint destruction associated with fitness disadvantages. Biomechanical capability plays a significant role in evolutionary fitness, and sustained joint insults such as immobility or undue biomechanical stress may serve as proxies for inferior fitness. By both hindering an individual's ability to compete for energy and increasing that individual's vulnerability to predation, feed-forward joint destruction may facilitate adaptive phenoptosis among impaired or senile members. Empirical data suggests that contrary to common belief, heavy joint use does not necessarily cause osteoarthritis, whereas immobility and neuropathy can predispose to the condition. From a Darwinian perspective, another process mediated by sympathetic activity, the alarm cry of attacked prey, simultaneously promotes the escape of kin while attracting predators and scavengers. By effectively enabling the martyrdom of biomechanically-challenged individuals, osteoarthritis may serve to optimize system energy efficiency in a similar fashion. This framework may generalize to other situations where regenerative capacity dissipates in conjunction with maturation, typically leading to fibrosis. By allowing environmental pressure to sort the phenotypes, imperfect repair mechanisms may accelerate adaptation and optimize long-term inclusive fitness for all individuals. As the basis of competition shifts from biomechanical to cognitive skills, and as novel triggers for physical stress emerge, osteoarthritis may now represent a modern maladaptation.}, } @article {pmid16572169, year = {2006}, author = {Jansen, VA and van Baalen, M}, title = {Altruism through beard chromodynamics.}, journal = {Nature}, volume = {440}, number = {7084}, pages = {663-666}, doi = {10.1038/nature04387}, pmid = {16572169}, issn = {1476-4687}, mesh = {*Altruism ; Biological Evolution ; Cooperative Behavior ; Game Theory ; *Hair Color/genetics ; Humans ; *Models, Biological ; Models, Genetic ; *Selection, Genetic ; Viscosity ; }, abstract = {The evolution of altruism, a behaviour that benefits others at one's own fitness expense, poses a darwinian paradox. The paradox is resolved if many interactions are with related individuals so that the benefits of altruism are reaped by copies of the altruistic gene in other individuals, a mechanism called kin selection. However, recognition of altruists could provide an alternative route towards the evolution of altruism. Arguably the simplest recognition system is a conspicuous, heritable tag, such as a green beard. Despite the fact that such genes have been reported, the 'green beard effect' has often been dismissed because it is unlikely that a single gene can code for altruism and a recognizable tag. Here we model the green beard effect and find that if recognition and altruism are always inherited together, the dynamics are highly unstable, leading to the loss of altruism. In contrast, if the effect is caused by loosely coupled separate genes, altruism is facilitated through beard chromodynamics in which many beard colours co-occur. This allows altruism to persist even in weakly structured populations and implies that the green beard effect, in the form of a fluid association of altruistic traits with a recognition tag, can be much more prevalent than hitherto assumed.}, } @article {pmid16537425, year = {2006}, author = {Zhou, X and Oi, FM and Scharf, ME}, title = {Social exploitation of hexamerin: RNAi reveals a major caste-regulatory factor in termites.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {103}, number = {12}, pages = {4499-4504}, pmid = {16537425}, issn = {0027-8424}, mesh = {Amino Acid Sequence ; Animals ; Carrier Proteins/genetics/*metabolism ; Gene Expression ; Insect Proteins/genetics/*metabolism ; Isoptera/genetics/*growth & development/metabolism ; Molecular Sequence Data ; RNA Interference ; }, abstract = {Lower termites express a unique form of eusocial polyphenism in that totipotent workers can differentiate into either soldier or reproductive caste phenotypes. In this initial effort using RNA interference in termites, we found that two hexamerin genes, Hex-1 and Hex-2, participate in the regulation of caste polyphenism. Our methodology involved a dual gene-silencing approach that used a single short-interfering RNA fragment to silence the two homologous hexamerin genes. We performed validation studies that evaluated effects on nontarget housekeeping genes, silencing of a nonhousekeeping control gene, and effects at the protein level. We found that the two hexamerin proteins, which are inducible by the morphogenetic juvenile hormone and which constitute a significant proportion of total termite protein, suppress juvenile-hormone-dependent worker differentiation to the soldier caste phenotype. This mechanism allows termite colonies to retain high proportions of altruistic worker caste members, thus apparently enhancing colony-inclusive fitness. These findings demonstrate a unique status quo regulatory mechanism for termite worker caste retention and provide an example of previously undescribed preadult developmental/caste-regulatory genes from any social insect.}, } @article {pmid16537121, year = {2006}, author = {Archie, EA and Moss, CJ and Alberts, SC}, title = {The ties that bind: genetic relatedness predicts the fission and fusion of social groups in wild African elephants.}, journal = {Proceedings. Biological sciences}, volume = {273}, number = {1586}, pages = {513-522}, pmid = {16537121}, issn = {0962-8452}, mesh = {Animals ; *Behavior, Animal ; DNA, Mitochondrial/chemistry/genetics ; Elephants/*genetics/psychology ; Female ; Genetics, Population ; Haplotypes ; Microsatellite Repeats/genetics ; Polymerase Chain Reaction/veterinary ; *Social Behavior ; }, abstract = {Many social animals live in stable groups. In contrast, African savannah elephants (Loxodonta africana) live in unusually fluid, fission-fusion societies. That is, 'core' social groups are composed of predictable sets of individuals; however, over the course of hours or days, these groups may temporarily divide and reunite, or they may fuse with other social groups to form much larger social units. Here, we test the hypothesis that genetic relatedness predicts patterns of group fission and fusion among wild, female African elephants. Our study of a single Kenyan population spans 236 individuals in 45 core social groups, genotyped at 11 microsatellite and one mitochondrial DNA (mtDNA) locus. We found that genetic relatedness predicted group fission; adult females remained with their first order maternal relatives when core groups fissioned temporarily. Relatedness also predicted temporary fusion between social groups; core groups were more likely to fuse with each other when the oldest females in each group were genetic relatives. Groups that shared mtDNA haplotypes were also significantly more likely to fuse than groups that did not share mtDNA. Our results suggest that associations between core social groups persist for decades after the original maternal kin have died. We discuss these results in the context of kin selection and its possible role in the evolution of elephant sociality.}, } @article {pmid16485773, year = {2005}, author = {Williams, BJ}, title = {Kin selection in human populations: theory reconsidered.}, journal = {Human biology}, volume = {77}, number = {4}, pages = {421-431}, doi = {10.1353/hub.2005.0070}, pmid = {16485773}, issn = {0018-7143}, mesh = {*Altruism ; *Biological Evolution ; Family ; Gene Frequency ; Humans ; Mathematics ; *Models, Genetic ; Models, Psychological ; *Selection, Genetic ; }, abstract = {Past considerations of kin selection have assumed a dyadic fitness exchange relationship between altruist and recipient. This approach does not account for all alleles affected by altruistic behavior. This can be corrected by focusing on matings rather than on individuals. I present a model that tries to account for fitness changes resulting from altruistic acts, not only for the altruist and recipient but also for their spouses, in an evolving population. Results from this model indicate that Hamilton's rule fails to predict when the altruism allele will increase in frequency and, more important, suggest that kin selection can, at most, account for low levels of a gene for altruism but only if fairly extreme conditions are met.}, } @article {pmid16477595, year = {2006}, author = {Levréro, F and Gatti, S and Ménard, N and Petit, E and Caillaud, D and Gautier-Hion, A}, title = {Living in nonbreeding groups: an alternative strategy for maturing gorillas.}, journal = {American journal of primatology}, volume = {68}, number = {3}, pages = {275-291}, doi = {10.1002/ajp.20223}, pmid = {16477595}, issn = {0275-2565}, mesh = {Age Factors ; Animal Migration ; Animals ; *Breeding ; Congo ; Female ; Gorilla gorilla/genetics/growth & development/*physiology ; Hierarchy, Social ; Male ; Population Dynamics ; *Sexual Behavior, Animal ; }, abstract = {The one-male reproductive strategy implies that maturing males are temporarily excluded from reproduction. In gorillas, these excluded males live either solitarily or in nonbreeding groups (NBGs) that are devoid of adult females. The dynamics of NBGs are not well known. In this study, which was conducted on a gorilla population (Gorilla gorilla gorilla) of 377 individuals that visited the Lokoué clearing in the Republic of Congo, we detail how the NBGs formed, and analyze their dynamics according to age-sex classes, the relatedness of members, and the origin and destination of transferring individuals. We discuss the potential benefits gained by individuals living in these groups. The NBGs included mainly immature males, most of which appeared to have migrated voluntarily from their natal groups. Some individuals (including juvenile females) came from disbanded breeding groups (BGs). Migrants preferentially joined NBGs that included a silverback male. Their dispersal patterns were not determined by their degree of relatedness, but they tended to associate with related silverbacks. In this way, the migrants could enhance their protection against predators and gain experience with different environmental conditions. By tolerating and protecting offspring, aging silverbacks could enhance their inclusive fitness. Finally, young and healthy silverbacks could increase their likelihood of forming a future BG when unrelated females joined them.}, } @article {pmid16475087, year = {2005}, author = {Roze, D and Rousset, F}, title = {Inbreeding depression and the evolution of dispersal rates: a multilocus model.}, journal = {The American naturalist}, volume = {166}, number = {6}, pages = {708-721}, doi = {10.1086/497543}, pmid = {16475087}, issn = {1537-5323}, mesh = {Animal Migration ; Animals ; Behavior, Animal ; Body Size ; Chromosome Mapping ; Female ; *Inbreeding ; Male ; *Models, Genetic ; Recombination, Genetic ; *Selection, Genetic ; }, abstract = {Inbreeding depression is one of the possible reasons organisms disperse. In this article, we present a two-locus model for the evolution of dispersal in the presence of inbreeding depression. The first locus codes for a modifier of the migration rate, while the second locus is a selected locus generating inbreeding depression. We express the change in frequency of the migration modifier as a function of allele frequencies and genetic associations and then use a quasi-equilibrium assumption to express genetic associations as functions of allele frequencies. Our model disentangles two effects of inbreeding depression: it gives an advantage to migrant individuals because their offspring are on average less homozygous, but it also decreases the degree of population structure, thus decreasing the strength of kin selection for dispersal. We then extend our model to include an infinite number of selected loci. When the cost of dispersal is not too high, the model predictions are confirmed by multilocus simulation results and show that inbreeding depression can have a substantial effect on the dispersal rate. For high costs of dispersal, we observe discrepancies between the model and the simulations, probably caused by associations among selected loci, which are neglected in the analysis.}, } @article {pmid16382816, year = {2003}, author = {Heath, KM}, title = {The effects of kin propinquity on infant mortality.}, journal = {Social biology}, volume = {50}, number = {3-4}, pages = {270-280}, doi = {10.1080/19485565.2003.9989076}, pmid = {16382816}, issn = {0037-766X}, mesh = {Adolescent ; Anthropology, Cultural ; Child ; Child, Preschool ; Church of Jesus Christ of Latter-day Saints/*history ; Family Characteristics/*ethnology ; Family Relations ; Female ; History, 19th Century ; Humans ; Infant ; Infant Care/*history ; Infant Mortality/*history ; Infant, Newborn ; Intergenerational Relations/*ethnology ; Marriage/ethnology/*history ; Risk Factors ; Social Environment ; Survival Analysis ; United States ; Utah/epidemiology ; }, abstract = {This study tests the grandmother hypothesis and analyzes the effect of kin propinquity on infant mortality in a 19th century American frontier communal, polygynous population. The study shows that the presence of maternal grandmothers, aunts, uncles, and paternal aunts were significantly associated with increased infant survivorship while grandfathers, paternal grandmothers, and paternal uncles showed little effect. This study has implications for understanding the evolution of a long postreproductive life span, postmarital residential strategies, and behavioral strategies that enhance inclusive fitness.}, } @article {pmid16357252, year = {2005}, author = {Scarborough, CL and Ferrari, J and Godfray, HC}, title = {Aphid protected from pathogen by endosymbiont.}, journal = {Science (New York, N.Y.)}, volume = {310}, number = {5755}, pages = {1781}, doi = {10.1126/science.1120180}, pmid = {16357252}, issn = {1095-9203}, support = {D19263/BB_/Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Aphids/*microbiology/physiology ; Enterobacteriaceae/genetics/*physiology ; Entomophthorales/pathogenicity/*physiology ; Molecular Sequence Data ; Spores, Fungal/physiology ; *Symbiosis ; }, abstract = {Aphids are associated with several facultative bacterial endosymbionts that may influence their interactions with other organisms. We show here that one of the three most common facultative symbionts of pea aphid (Acyrthosiphon pisum), the bacterium Regiella insecticola, has a major effect on host resistance to a fungal pathogen. Experimental establishment of the bacterium in uninfected aphid clones led to higher survival after fungal attack. The bacteria also increased the aphid's inclusive fitness, because the presence of the symbiont reduced the probability of fungal sporulation on aphid cadavers, hence lowering the rate of transmission of the disease to nearby related aphids.}, } @article {pmid16351832, year = {2001}, author = {Wieser, W}, title = {Private and collective interests; conflicts and solutions: the central theme of current thinking in evolutionary biology.}, journal = {Zoology (Jena, Germany)}, volume = {104}, number = {3-4}, pages = {184-191}, doi = {10.1078/0944-2006-00023}, pmid = {16351832}, issn = {0944-2006}, abstract = {The statement made by the population geneticist Theodosius Dobzhansky (1973): "Nothing in Biology Makes Sense Except in the Light of Evolution", is often quoted as a crucially important generalization on the nature of biology. I am inclined to consider as equally important the statement: "Nothing in Evolutionary Biology Makes Sense Except in the Light of Conflicts between Parts and Systems." This generalization takes account of the dynamic nature of biological phenomena, but also of the fact that the study of transitions from autonomous units to cooperative systems has become one of the most exciting and scientifically rewarding enterprises in all of organismic biology. The problems encountered and the speculations generated in the course of this enterprise will be either of the more unit-centered or of the more system-centered type, most biologists tending to lean towards one or the other. This explains why evolutionary biology is fraught with so many antagonistic attitudes and polarizing points of view. In this essay I want specifically to draw attention to and discuss the following issues which in recent years have polarized biologists: the dual nature of genes; the logic of Hamilton's rule; the relationship between kin selection, signalling networks and systemic manipulation; the semantic problem of progress in evolution; and the evolutionary consequences of the vastly differing time scales over which genotypic and phenotypic information processing occurs in higher animals.}, } @article {pmid16313605, year = {2005}, author = {Gibson, RM and Pires, D and Delaney, KS and Wayne, RK}, title = {Microsatellite DNA analysis shows that greater sage grouse leks are not kin groups.}, journal = {Molecular ecology}, volume = {14}, number = {14}, pages = {4453-4459}, doi = {10.1111/j.1365-294X.2005.02746.x}, pmid = {16313605}, issn = {0962-1083}, mesh = {Animals ; California ; Galliformes/genetics/*physiology ; Genetic Markers/genetics ; *Genetics, Population ; Genotype ; Linkage Disequilibrium ; Male ; Microsatellite Repeats/genetics ; Oligonucleotides ; *Selection, Genetic ; Sexual Behavior, Animal/*physiology ; *Social Behavior ; }, abstract = {The spectacular social courtship displays of lekking birds are thought to evolve via sexual selection, but this view does not easily explain the participation of many males that apparently fail to mate. One of several proposed solutions to this 'lek skew paradox' is that kin selection favours low-ranking males joining leks to increase the fitness of closely related breeders. We investigated the potential for kin selection to operate in leks of the greater sage grouse, Centrocercus urophasianus, by estimating relatedness between lekking males using microsatellite DNA markers. We also calibrated these estimates using data from known families. Mean relatedness within leks was statistically indistinguishable from zero. We also found no evidence for local clustering of kin during lek display, although males tended to range closer to kin when off the lek. These results make kin selection an unlikely solution to the lek skew paradox in sage grouse. Together with other recent studies, they also raise the question of why kin selection apparently promotes social courtship in some lekking species, but not in others.}, } @article {pmid16306537, year = {2005}, author = {Noor, MA and Johnson, NA}, title = {A kingpin of academic inclusive fitness: the history and contributions of Bruce Grant.}, journal = {Genetics}, volume = {171}, number = {3}, pages = {867-871}, pmid = {16306537}, issn = {0016-6731}, mesh = {Animals ; Drosophila melanogaster/*genetics ; Genetic Research/*history ; History, 20th Century ; History, 21st Century ; Mentors/*history ; Moths/*genetics ; Wasps/*genetics ; }, } @article {pmid16257418, year = {2006}, author = {Wilkins, JF}, title = {Tissue-specific reactivation of gene expression at an imprinted locus.}, journal = {Journal of theoretical biology}, volume = {240}, number = {2}, pages = {277-287}, doi = {10.1016/j.jtbi.2005.09.007}, pmid = {16257418}, issn = {0022-5193}, mesh = {Alleles ; Animals ; Dosage Compensation, Genetic ; Epigenesis, Genetic ; Female ; Gene Expression ; *Gene Expression Regulation, Developmental ; Genetic Diseases, Inborn/genetics ; Genetic Drift ; *Genomic Imprinting ; Humans ; Male ; *Models, Genetic ; Mutation ; }, abstract = {Genomic imprinting is the phenomenon where the expression pattern of an allele at a locus differs depending on the allele's parent of origin. In most cases, one of the two alleles is transcriptionally silent. Recent empirical work has shown some genes to be imprinted in a tissue-specific manner, where the silenced allele becomes reactivated in particular cell lineages during development. Here I describe an evolutionary model of tissue-specific transcriptional reactivation. The model describes the relationships among various inclusive fitness functions and phenotypic effects necessary for natural selection to favor the epigenetic reprogramming required for this sort of reactivation, and makes predictions regarding the nature and magnitude of phenotypic and fitness consequences of mutations in particular somatic tissues. In particular, if an imprinted gene is reactivated in one of two tissues that interact in producing a particular phenotype, expression of the gene in those two tissues is expected to have opposite phenotypic effects. The model predicts that in some cases, mutations affecting the silenced allele at an imprinted locus may be phenotypically more severe than those affecting the expressed allele. These predictions are contrasted with those of an alternative explanation for reactivation: protection against deleterious recessive somatic mutations. The inclusive-fitness model of reactivation indicates that the intragenomic conflicts present in the parental germ lines and developing embryo persist though adult life, and can have complex effects on phenotypes and patterns of gene expression in somatic tissues.}, } @article {pmid16254893, year = {2005}, author = {Allen, JS and Bruss, J and Damasio, H}, title = {The aging brain: the cognitive reserve hypothesis and hominid evolution.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {17}, number = {6}, pages = {673-689}, doi = {10.1002/ajhb.20439}, pmid = {16254893}, issn = {1042-0533}, support = {NS 19632/NS/NINDS NIH HHS/United States ; }, mesh = {Aging/*physiology ; Animals ; *Biological Evolution ; Brain/*growth & development ; Cognition/*physiology ; Hominidae/*anatomy & histology ; Humans ; }, abstract = {Compared to other primates, humans live a long time and have large brains. Recent theories of the evolution of human life history stages (grandmother hypothesis, intergenerational transfer of information) lend credence to the notion that selection for increased life span and menopause has occurred in hominid evolution, despite the reduction in the force of natural selection operating on older, especially post-reproductive, individuals. Theories that posit the importance (in an inclusive fitness sense) of the survival of older individuals require them to maintain a reasonably high level of cognitive function (e.g., memory, communication). Patterns of brain aging and factors associated with healthy brain aging should be relevant to this issue. Recent neuroimaging research suggests that, in healthy aging, human brain volume (gray and white matter) is well-maintained until at least 60 years of age; cognitive function also shows only nonsignificant declines at this age. The maintenance of brain volume and cognitive performance is consistent with the idea of a significant post- or late-reproductive life history stage. A clinical model, "the cognitive reserve hypothesis," proposes that both increased brain volume and enhanced cognitive ability may contribute to healthy brain aging, reducing the likelihood of developing dementia. Selection for increased brain size and increased cognitive ability in hominid evolution may therefore have been important in selection for increased lifespan in the context of intergenerational social support networks.}, } @article {pmid16250466, year = {2005}, author = {Linksvayer, TA and Wade, MJ}, title = {The evolutionary origin and elaboration of sociality in the aculeate Hymenoptera: maternal effects, sib-social effects, and heterochrony.}, journal = {The Quarterly review of biology}, volume = {80}, number = {3}, pages = {317-336}, doi = {10.1086/432266}, pmid = {16250466}, issn = {0033-5770}, support = {GM65414/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Genetics, Population ; *Hymenoptera/genetics ; *Social Behavior ; }, abstract = {We discuss the evolutionary origin and elaboration of sociality using an indirect genetic effects perspective. Indirect genetic effects models simultaneously consider zygotic genes, genes expressed in social partners (especially mothers and siblings), and the interactions between them. Incorporation of these diverse genetic effects should lead to more realistic models of social evolution. We first review haplodiploidy as a factor that promotes the evolution of eusociality. Social insect biologists have doubted the importance of relatedness asymmetry caused by haplodiploidy and focused on other predisposing factors such as maternal care. However; indirect effects theory shows that maternal care evolves more readily in haplodiploids, especially with inbreeding and despite multiple mating. Because extended maternal care is believed to be a precondition for the evolution of eusociality, the evolutionary bias towards maternal care in haplodiploids may result in a further bias towards eusociality in these groups. Next, we compare kin selection and parental manipulation and then briefly review additional hypotheses for the evolutionary origin of eusociality. We present a verbal model for the evolutionary origin and elaboration of sib-social care from maternal care based on the modification of the timing of expression of maternal care behaviors. Specifically, heterochrony genes cause maternal care behaviors to be expressed prereproductively towards siblings instead of postreproductively towards offspring. Our review demonstrates that both maternal effect genes (expressed in a parental manipulation manner) and direct effect zygotic genes (expressed in an offspring control manner) are likely involved in the evolution of eusociality. We conclude by describing theoretical and empirical advances with indirect genetic effects and sociogenomics, and we provide specific quantitative genetic and genomic predictions from our heterochrony model for the evolutionary origin and elaboration of eusociality.}, } @article {pmid16202104, year = {2005}, author = {Ost, M and Vitikainen, E and Waldeck, P and Sundström, L and Lindström, K and Hollmén, T and Franson, JC and Kilpi, M}, title = {Eider females form non-kin brood-rearing coalitions.}, journal = {Molecular ecology}, volume = {14}, number = {12}, pages = {3903-3908}, doi = {10.1111/j.1365-294X.2005.02694.x}, pmid = {16202104}, issn = {0962-1083}, mesh = {Animals ; Ducks/genetics/*physiology ; Female ; Finland ; Gene Frequency ; Genotype ; *Maternal Behavior ; Microsatellite Repeats/genetics ; *Nesting Behavior ; Sequence Analysis, DNA ; }, abstract = {Kin selection is a powerful tool for understanding cooperation among individuals, yet its role as the sole explanation of cooperative societies has recently been challenged on empirical grounds. These studies suggest that direct benefits of cooperation are often overlooked, and that partner choice may be a widespread mechanism of cooperation. Female eider ducks (Somateria mollissima) may rear broods alone, or they may pool their broods and share brood-rearing. Females are philopatric, and it has been suggested that colonies may largely consist of related females, which could promote interactions among relatives. Alternatively, shared brood care could be random with respect to relatedness, either because brood amalgamations are accidental and nonadaptive, or through group augmentation, assuming that the fitness of all group members increases with group size. We tested these alternatives by measuring the relatedness of co-tending eider females in enduring coalitions with microsatellite markers. Females formed enduring brood-rearing coalitions with each other at random with respect to relatedness. However, based on previous data, partner choice is nonrandom and dependent on female body condition. We discuss potential mechanisms underlying eider communal brood-rearing decisions, which may be driven by the specific ecological conditions under which sociality has evolved in this species.}, } @article {pmid16195927, year = {2006}, author = {Seno, H}, title = {Group size determined by fusion and fission. A mathematical modelling with inclusive fitness.}, journal = {Journal of mathematical biology}, volume = {52}, number = {1}, pages = {70-92}, pmid = {16195927}, issn = {0303-6812}, mesh = {Animals ; Behavior ; Humans ; Mathematics ; *Models, Biological ; Population Density ; Population Dynamics ; }, abstract = {We consider a mathematical model for the group size determination by the intra-reactions, self-growth, ostracism and fission within a group, and by the inter-reactions, immigration and fusion between two groups. In some group reactions, a conflict between two groups occurs about the reaction to change the group size. We construct a mathematical model to consider such conflict, taking into account the inclusive fitness of members in each group. In the conflict about the fusion between two groups, our analysis shows that the smaller group wants to fuse, while the larger does not. Also the criterion to resolve the conflict is discussed, and some numerical examples are given, too. It is concluded that, depending on the deviation in the total cost paid for the conflict by counterparts, the group reactions could result in a terminal group size different from that reached only by a sequence of outsider's immigrations into a group.}, } @article {pmid16194555, year = {2006}, author = {Milchtaich, I}, title = {Comparative statics of games between relatives.}, journal = {Theoretical population biology}, volume = {69}, number = {2}, pages = {203-210}, doi = {10.1016/j.tpb.2005.08.002}, pmid = {16194555}, issn = {0040-5809}, mesh = {*Altruism ; Cooperative Behavior ; *Family Relations ; *Game Theory ; Gene Frequency ; Humans ; *Models, Biological ; Physical Fitness ; *Selection, Genetic ; }, abstract = {According to Hamilton's theory of kin selection, species tend to evolve behavior such that each organism appears to be attempting to maximize its inclusive fitness. In particular, two neighbors are likely to help each other if the cost of doing so is less than the benefit multiplied by r, their coefficient of relatedness. Since the latter is less than unity, mutual altruism benefits both neighbors. However, is it theoretically possible that acting so as to maximize the inclusive, rather than personal, fitness may harm both parties. This may occur in strategic symmetric pairwise interactions (more specifically, nxn games), in which the outcome depends on both sides' actions. In this case, the equilibrium outcome may be less favorable to the interactants' personal fitness than if each of them acted so as to maximize the latter. This paper shows, however, that such negative effect of relatedness on fitness is incompatible with evolutionary stability. If the symmetric equilibrium strategies are evolutionarily stable, a higher coefficient of relatedness can only entail higher personal fitness for the two neighbors. This suggests that negative comparative statics as above are not likely to occur in nature.}, } @article {pmid16191611, year = {2005}, author = {Hoffman, JI and Amos, W}, title = {Does kin selection influence fostering behaviour in Antarctic fur seals (Arctocephalus gazella)?.}, journal = {Proceedings. Biological sciences}, volume = {272}, number = {1576}, pages = {2017-2022}, pmid = {16191611}, issn = {0962-8452}, mesh = {*Altruism ; Animals ; Atlantic Islands ; Female ; Fur Seals/genetics/*physiology ; Genotype ; Maternal Behavior/*physiology ; Microsatellite Repeats/genetics ; Research Design ; *Selection, Genetic ; }, abstract = {A recent observation that female Antarctic fur seals foster pups born to related females raises the fascinating possibility that kin selection may promote altruistic behaviour even on a crowded breeding beach, where individual interactions are frequent and complex. However, the use of genetic markers to identify small numbers of unusually highly related individuals is fraught with difficulty due to the likely presence of genotyping errors and related problems. Consequently, we examined an enlarged dataset where errors had been reduced to an absolute minimum by a combination of close scrutiny and repeat genotyping. We find no support for the idea that females preferentially suckle pups born to female relatives. Instead, the previously reported pattern can be explained by a combination of genotyping errors and de novo mutations. Our study emphasizes the need for caution when interpreting rare events that occur at a rate approaching that expected for normal genotyping errors.}, } @article {pmid16163356, year = {2005}, author = {Rossiter, SJ and Ransome, RD and Faulkes, CG and Le Comber, SC and Jones, G}, title = {Mate fidelity and intra-lineage polygyny in greater horseshoe bats.}, journal = {Nature}, volume = {437}, number = {7057}, pages = {408-411}, doi = {10.1038/nature03965}, pmid = {16163356}, issn = {1476-4687}, mesh = {Animals ; Biological Evolution ; Chiroptera/*genetics/*physiology ; Cooperative Behavior ; Female ; Male ; Microsatellite Repeats/genetics ; *Pedigree ; Sexual Behavior, Animal/*physiology ; }, abstract = {Mating strategies that lead to increased kinship within socially cooperative groups may offer inclusive fitness benefits to individuals, but can also result in higher levels of inbreeding. Here we show in a sexually segregated bat species that females avoid this conflict through two mating behaviours. First, most females revisit and breed with specific, individual males across years, so that their single offspring born in different years are full siblings. Second, relatives in the maternal line, including mothers and daughters, share breeding partners (intra-lineage polygyny) more often than expected by chance. Although these behaviours increased levels of co-ancestry among colony members, there was no concomitant rise in inbreeding. We suggest that when females engage in mate fidelity and intra-lineage polygyny, kin ties among female roost mates will be strengthened, thereby potentially contributing to social group cohesiveness. Our findings reveal the hidden complexity that can underlie polygynous breeding, and highlight a new potential route by which female mate choice could influence social evolution.}, } @article {pmid16157878, year = {2005}, author = {Wilson, EO and Hölldobler, B}, title = {Eusociality: origin and consequences.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {102}, number = {38}, pages = {13367-13371}, pmid = {16157878}, issn = {0027-8424}, mesh = {Animals ; *Biological Evolution ; Insecta/*physiology ; *Selection, Genetic ; *Social Behavior ; }, abstract = {In this new assessment of the empirical evidence, an alternative to the standard model is proposed: group selection is the strong binding force in eusocial evolution; individual selection, the strong dissolutive force; and kin selection (narrowly defined), either a weak binding or weak dissolutive force, according to circumstance. Close kinship may be more a consequence of eusociality than a factor promoting its origin. A point of no return to the solitary state exists, as a rule when workers become anatomically differentiated. Eusociality has been rare in evolution, evidently due to the scarcity of environmental pressures adequate to tip the balance among countervailing forces in favor of group selection. Eusociality in ants and termites in the irreversible stage is the key to their ecological dominance and has (at least in ants) shaped some features of internal phylogeny. Their colonies are consistently superior to solitary and preeusocial competitors, due to the altruistic behavior among nestmates and their ability to organize coordinated action by pheromonal communication.}, } @article {pmid16156824, year = {2005}, author = {Seddon, N and Amos, W and Adcock, G and Johnson, P and Kraaijeveld, K and Kraaijeveld-Smit, FJ and Lee, W and Senapathi, GD and Mulder, RA and Tobias, JA}, title = {Mating system, philopatry and patterns of kinship in the cooperatively breeding subdesert mesite Monias benschi.}, journal = {Molecular ecology}, volume = {14}, number = {11}, pages = {3573-3583}, doi = {10.1111/j.1365-294X.2005.02675.x}, pmid = {16156824}, issn = {0962-1083}, mesh = {Animals ; Birds/*physiology ; Female ; Madagascar ; Male ; Microsatellite Repeats/genetics ; *Models, Biological ; Nesting Behavior/*physiology ; Observation ; *Polymorphism, Genetic ; *Selection, Genetic ; Sex Factors ; Sexual Behavior, Animal/*physiology ; Spatial Behavior/*physiology ; }, abstract = {In the first molecular study of a member of the threatened avian family, Mesitornithidae, we used nine polymorphic microsatellite loci to elucidate parentage, patterns of within-group kinship and occurrence of extra-group paternity in the subdesert mesite Monias benschi, of southwest Madagascar. We found this cooperatively breeding species to have a very fluid mating system. There was evidence of genetic monogamy and polygynandry: of the nine groups with multiple offspring, six contained one breeding pair with unrelated helpers and three contained multiple male and female breeders with related helpers. Although patterns of within-group kinship varied, there was a strong positive relationship between group size and relatedness, suggesting that groups form by natal philopatry. There was also a strong positive correlation between within-sex and between-sex relatedness, indicating that unlike most cooperatively breeding birds, philopatry involved both sexes. In contrast to predictions of kin selection and reproductive skew models, all monogamous groups contained unrelated individuals, while two of the three polygynandrous groups were families. Moreover, although between-group variation in seasonal reproductive success was related to within-group female relatedness, relatedness among males and between the sexes had no bearing on a group's reproductive output. While kin selection may underlie helping behaviour in females, factors such as direct long-term fitness benefits of group living probably determine helping in males. Of the 14 offspring produced by fully sampled groups, at least two were sired by males from neighbouring groups: one by a breeding male and one by a nonbreeding male, suggesting that males may augment their reproductive success through extra-group paternity.}, } @article {pmid16101779, year = {2005}, author = {Fraser, DJ and Duchesne, P and Bernatchez, L}, title = {Migratory charr schools exhibit population and kin associations beyond juvenile stages.}, journal = {Molecular ecology}, volume = {14}, number = {10}, pages = {3133-3146}, doi = {10.1111/j.1365-294X.2005.02657.x}, pmid = {16101779}, issn = {0962-1083}, mesh = {Alleles ; Animal Migration/*physiology ; Animals ; Behavior, Animal/*physiology ; DNA/chemistry/genetics ; Female ; Fresh Water ; Genetic Variation ; Genetics, Population ; Male ; Microsatellite Repeats ; Population Dynamics ; Quebec ; Trout/*genetics/physiology ; }, abstract = {Few studies have critically investigated the genetic composition of wild fish schools. Yet, such investigations may have profound implications for the understanding of social organization and population differentiation in both fundamental and applied research. Using 20 microsatellite loci, we investigated the composition of 53 schools (total n = 211) of adult and subadult migratory brook charr (Salvelinus fontinalis) sampled from the known feeding areas of two populations inhabiting Mistassini Lake (Québec, Canada). We specifically tested whether (i) school members originated from the same population, (ii) individuals from the same population within schools were kin (half- or full-siblings), and (iii) kin schooling relationships differed between sexes. Randomization tests revealed a tendency for most schools to be population specific, although some schools were population mixtures. Significantly more kin were found within schools than expected at random for both populations (approximately 21-34% of the total number of school members). This result, combined with the observed size range of individuals, indicated that stable associations between kin may occur beyond juvenile stages for up to 4 years. Nevertheless, a high proportion of school members were non-kin (approximately 66-79%). No differences were detected between sexes in the propensity to school with kin. We discuss the hypothesis that the stable kin groups, rather than arising from kin selection, may instead be a by-product of familiarity based on individual selection for the maintenance of local adaptations related to migration (natal and feeding area philopatry). Our results are noteworthy because they suggest that there is some degree of permanence in the composition of wild fish schools. Additionally, they support the hypothesis that schools can be hierarchically structured (from population members down to family groups) and are thus nonrandom genetic entities.}, } @article {pmid16050107, year = {2005}, author = {Wenseleers, T and Badcock, NS and Erven, K and Tofilski, A and Nascimento, FS and Hart, AG and Burke, TA and Archer, ME and Ratnieks, FL}, title = {A test of worker policing theory in an advanced eusocial wasp, Vespula rufa.}, journal = {Evolution; international journal of organic evolution}, volume = {59}, number = {6}, pages = {1306-1314}, pmid = {16050107}, issn = {0014-3820}, mesh = {Animals ; England ; Female ; Gene Frequency ; Male ; Microsatellite Repeats/genetics ; *Models, Biological ; Observation ; Ovum ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; *Social Dominance ; Wasps/*physiology ; }, abstract = {Mutual policing is an important mechanism for maintaining social harmony in group-living organisms. In some ants, bees, and wasps, workers police male eggs laid by other workers in order to maintain the reproductive primacy of the queen. Kin selection theory predicts that multiple mating by the queen is one factor that can selectively favor worker policing. This is because when the queen is mated to multiple males, workers are more closely related to queen's sons than to the sons of other workers. Here we provide an additional test of worker policing theory in Vespinae wasps. We show that the yellowjacket Vespula rufa is characterized by low mating frequency, and that a significant percentage of the males are workers' sons. This supports theoretical predictions for paternities below 2, and contrasts with other Vespula species, in which paternities are higher and few or no adult males are worker produced, probably due to worker policing, which has been shown in one species, Vespula vulgaris. Behavioral observations support the hypothesis that V. rufa has much reduced worker policing compared to other Vespula. In addition, a significant proportion of worker-laid eggs were policed by the queen.}, } @article {pmid16048775, year = {2005}, author = {Stiver, KA and Dierkes, P and Taborsky, M and Gibbs, HL and Balshine, S}, title = {Relatedness and helping in fish: examining the theoretical predictions.}, journal = {Proceedings. Biological sciences}, volume = {272}, number = {1572}, pages = {1593-1599}, pmid = {16048775}, issn = {0962-8452}, mesh = {Animals ; Body Weights and Measures ; Cichlids/genetics/*physiology ; *Cooperative Behavior ; Female ; Fresh Water ; Male ; Reproduction/genetics ; *Selection, Genetic ; Sex Factors ; Sex Ratio ; Territoriality ; Zambia ; }, abstract = {Many studies have attempted to explain the evolution of cooperation, yet little attention has been paid to what factors control the amount or kind of cooperation performed. Kin selection theory suggests that more cooperation, or help, should be given by relatives. However, recent theory suggests that under specific ecological and demographic conditions, unrelated individuals must 'pay to stay' in the group and therefore may help more. We tested these contrasting predictions using the cooperatively breeding fish, Neolamprologus pulcher, and found that the degree of work effort by helpers depended on which helping behaviours were considered and on their level of relatedness to the breeding male or female. In the field, helpers unrelated to the breeding male performed more territory defence, while helpers unrelated to the breeding female contributed less to territory defence. In the laboratory, unrelated group members helped more. Our work demonstrates that a number of factors in addition to kinship shape cooperative investment patterns.}, } @article {pmid16046225, year = {2006}, author = {Grafen, A}, title = {Optimization of inclusive fitness.}, journal = {Journal of theoretical biology}, volume = {238}, number = {3}, pages = {541-563}, doi = {10.1016/j.jtbi.2005.06.009}, pmid = {16046225}, issn = {0022-5193}, mesh = {Adaptation, Biological ; Animals ; Gene Frequency ; Genetic Variation ; Genome ; Models, Biological ; Phenotype ; *Selection, Genetic ; *Social Behavior ; }, abstract = {The first fully explicit argument is given that broadly supports a widespread belief among whole-organism biologists that natural selection tends to lead to organisms acting as if maximizing their inclusive fitness. The use of optimization programs permits a clear statement of what this belief should be understood to mean, in contradistinction to the common mathematical presumption that it should be formalized as some kind of Lyapunov or even potential function. The argument reveals new details and uncovers latent assumptions. A very general genetic architecture is allowed, and there is arbitrary uncertainty. However, frequency dependence of fitnesses is not permitted. The logic of inclusive fitness immediately draws together various kinds of intra-genomic conflict, and the concept of 'p-family' is introduced. Inclusive fitness is thus incorporated into the formal Darwinism project, which aims to link the mathematics of motion (difference and differential equations) used to describe gene frequency trajectories with the mathematics of optimization used to describe purpose and design. Important questions remain to be answered in the fundamental theory of inclusive fitness.}, } @article {pmid16029479, year = {2005}, author = {Sutherland, DR and Spencer, PB and Singleton, GR and Taylor, AC}, title = {Kin interactions and changing social structure during a population outbreak of feral house mice.}, journal = {Molecular ecology}, volume = {14}, number = {9}, pages = {2803-2814}, doi = {10.1111/j.1365-294X.2005.02623.x}, pmid = {16029479}, issn = {0962-1083}, mesh = {Alleles ; Animals ; Female ; *Genetics, Population ; Mice/*physiology ; Microsatellite Repeats/genetics ; *Models, Theoretical ; Movement/physiology ; Population Density ; Population Dynamics ; Seasons ; Selection, Genetic ; *Social Behavior ; Victoria ; }, abstract = {Populations of feral house mice (Mus domesticus L.) in Australia undergo multiannual fluctuations in density, and these outbreaks may be partly driven by some change in behavioural self-regulation. In other vertebrate populations with multiannual fluctuations, changes in kin structure have been proposed as a causal mechanism for changes in spacing behaviour, which consequently result in density fluctuations. We tested the predictions of two alternative conceptual models based on kin selection in a population of house mice during such an outbreak. Both published models (Charnov & Finerty 1980; Lambin & Krebs 1991) propose that the level of relatedness between interacting individuals affects their behavioural response and that this changes with population density, though the nature of this relationship differs between the two models. Neither of the models was consistent with all observed changes in relatedness between interacting female mice; however, our results suggested that changes in kin structure still have potential for explaining why mouse outbreaks begin. Therefore, we have developed a variant of one of these conceptual models suggesting that the maintenance of female kin groups through the preceding winter significantly improves recruitment during the subsequent breeding season, and is therefore necessary for mouse outbreaks. We provide six testable predictions to falsify this hypothesis.}, } @article {pmid16010468, year = {2005}, author = {Rahman, Q and Hull, MS}, title = {An empirical test of the kin selection hypothesis for male homosexuality.}, journal = {Archives of sexual behavior}, volume = {34}, number = {4}, pages = {461-467}, doi = {10.1007/s10508-005-4345-6}, pmid = {16010468}, issn = {0004-0002}, mesh = {Adult ; England ; Family Relations ; *Gender Identity ; *Homosexuality, Male/psychology ; Humans ; *Identification, Psychological ; Male ; Psychometrics ; *Sibling Relations ; *Social Adjustment ; Surveys and Questionnaires ; }, abstract = {The current investigation, following Bobrow and Bailey (2001), aimed to test the kin selection theory of homosexuality in human males using a survey design. A total of 60 heterosexual and 60 homosexual men from England completed items measuring psychological and behavioral indices of "special design" as predicted by adaptation due to kin selection. There were no significant differences between heterosexual and homosexual men in general familial affinity, generous feelings (willingness to provide financial and emotional resources), and benevolent tendencies (such as willingness to baby-sit). These remained non-significant after co-varying for level of personal income (higher among homosexual men), psychological gender, and interest in children. Overall, little support was found for the kin selection theory in a community sample.}, } @article {pmid16006333, year = {2005}, author = {Liebig, J and Monnin, T and Turillazzi, S}, title = {Direct assessment of queen quality and lack of worker suppression in a paper wasp.}, journal = {Proceedings. Biological sciences}, volume = {272}, number = {1570}, pages = {1339-1344}, pmid = {16006333}, issn = {0962-8452}, mesh = {Animals ; Female ; Fertility/physiology ; Italy ; Population Density ; Reproduction/physiology ; Sexual Behavior, Animal/*physiology ; *Social Dominance ; Video Recording ; Wasps/*physiology ; }, abstract = {Assessing a conspecific's potential is often crucial to increase one's fitness, e.g. in female choice, contests with rivals or reproductive conflicts in animal societies. In the latter, helpers benefit from accurately assessing the fertility of the breeder as an indication of inclusive fitness. There is evidence that this can be achieved using chemical correlates of reproductive activity. Here, we show that queen quality can be assessed by directly monitoring her reproductive output. In the paper wasp Polistes dominulus, we mimicked a decrease in queen fertility by regularly removing brood. This triggered ovarian development and egg-laying by many workers, which strongly suggests that brood abundance is a reliable cue of queen quality. Brood abundance can be monitored when workers perform regular brood care in small size societies where each brood element is kept in a separate cell. Our results also show that although the queen was not manipulated, and thus remained healthy and fully fertile, she did not control worker egg-laying. Nevertheless, when workers laid eggs, the queen secured a near reproductive monopoly by selectively destroying these eggs, a mechanism known as 'queen policing'. By contrast, workers destroyed comparatively few queen-laid eggs, but did destroy each other's eggs.}, } @article {pmid16005306, year = {2005}, author = {Wild, G and Taylor, PD}, title = {A kin-selection approach to the resolution of sex-ratio conflict between mates.}, journal = {Journal of theoretical biology}, volume = {236}, number = {2}, pages = {126-136}, doi = {10.1016/j.jtbi.2005.03.003}, pmid = {16005306}, issn = {0022-5193}, mesh = {Animals ; *Biological Evolution ; Fathers ; Female ; Genotype ; Male ; *Models, Genetic ; Mothers ; Nesting Behavior ; *Pair Bond ; *Parenting ; Phenotype ; *Sex Ratio ; }, abstract = {We investigate an instance of conflict between mates over the sex ratio of their brood. We construct a kin-selection model for the evolution of the sex ratio assuming local resource competition (LRC) among females. We explore two basic scenarios: (a) the case where parents make simultaneous sex-ratio decisions (the simultaneous allocation model); and (b) the case where parental sex-ratio decisions occur one after the other (the sequential allocation model). In the simultaneous investment model, resolution of the conflict between mates depends on the extent to which relative paternal contribution influences the brood sex ratio. In the sequential allocation model, fathers determine primary sex-ratio through fertilization bias; then mothers modify the paternal sex-ratio decision by adjusting the level of investment of some resource that contributes to offspring survival. Under the sequential model, a compromise is always achieved; however this compromise favours one perspective or the other, depending on the extent to which maternal investment influences offspring survival.}, } @article {pmid15969731, year = {2005}, author = {Cutrera, AP and Lacey, EA and Busch, C}, title = {Genetic structure in a solitary rodent (Ctenomys talarum): implications for kinship and dispersal.}, journal = {Molecular ecology}, volume = {14}, number = {8}, pages = {2511-2523}, doi = {10.1111/j.1365-294X.2005.02551.x}, pmid = {15969731}, issn = {0962-1083}, mesh = {Animals ; Argentina ; *Demography ; Electrophoresis ; Female ; Gene Frequency ; *Genetic Variation ; *Genetics, Population ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; Rodentia/*genetics ; Sex Factors ; }, abstract = {The genetic structure of a population provides critical insights into patterns of kinship and dispersal. Although genetic evidence of kin structure has been obtained for multiple species of social vertebrates, this aspect of population biology has received considerably less attention among solitary taxa in which spatial and social relationships are unlikely to be influenced by kin selection. Nevertheless, significant kin structure may occur in solitary species, particularly if ecological or life history traits limit individual vagility. To explore relationships between genetic structure, kinship, and dispersal in a solitary vertebrate, we compared patterns of genetic variation in two demographically distinct populations of the talar tuco-tuco (Ctenomys talarum), a solitary species of subterranean rodent from Buenos Aires Province, Argentina. Based on previous field studies of C. talarum at Mar de Cobo (MC) and Necochea (NC), we predicted that natal dispersal in these populations is male biased, with dispersal distances for males and females being greater at NC. Analyses of 12 microsatellite loci revealed that in both populations, kin structure was more apparent among females than among males. Between populations, kinship and genetic substructure were more pronounced at MC. Thus, our findings were consistent with predicted patterns of dispersal for these animals. Collectively, these results indicate that populations of this solitary species are characterized by significant kin structure, suggesting that, even in the absence of sociality and kin selection, the spatial distributions and movements of individuals may significantly impact patterns of genetic diversity among conspecifics.}, } @article {pmid15965260, year = {2005}, author = {Lessard, S}, title = {Kin selection is implicated in partial sib-mating populations with constant viability differences before mating.}, journal = {Genetics}, volume = {171}, number = {1}, pages = {407-413}, pmid = {15965260}, issn = {0016-6731}, mesh = {Algorithms ; Alleles ; Animals ; Female ; Gene Frequency ; Genetics, Population ; *Inbreeding ; Male ; *Models, Genetic ; Mutation ; Reproduction/genetics ; *Selection, Genetic ; }, abstract = {The change in the frequency of a rare mutant allele under constant sex-differentiated viability selection in an infinite, partial full-sib mating population is studied. The diplo-diploid and haplo-diploid polygynous models are considered with a Poisson distribution for the number of offspring produced by every mated female. Reproduction is followed by weak selection among the offspring and then mating to form the next generation. It is shown that the rate of change with respect to the frequency of the mutant allele and the intensity of selection can be expressed in terms of costs or benefits of substituting the mutant type for the wild type, which correspond to average excesses in viability in females and males, multiplied by coefficients of relatedness to the individuals affected by such a substitution and reproductive values associated to the sexes of these individuals. This reveals hidden interactions between mated individuals and between males for mating, the former having positive effects on the reproductive success of related individuals and the latter having negative effects. Such interactions are the result of reproductive constraints when a fixed proportion of females must mate with a male sib and all females are fertilized as long as one mate is available. However, they affect the change in allele frequency because there is inbreeding or relatedness between mates and more generally relatedness between interacting individuals. Surprisingly, the effects of these interactions cancel out in a diploid population when the number of offspring is large enough so that the possibility for a female to have no male sib to mate with can be neglected and the viability differences are the same in both sexes.}, } @article {pmid15953618, year = {2005}, author = {van Veelen, M}, title = {On the use of the Price equation.}, journal = {Journal of theoretical biology}, volume = {237}, number = {4}, pages = {412-426}, doi = {10.1016/j.jtbi.2005.04.026}, pmid = {15953618}, issn = {0022-5193}, mesh = {Animals ; Biological Evolution ; Factor Analysis, Statistical ; Mathematical Computing ; Models, Genetic ; *Models, Statistical ; Probability Theory ; }, abstract = {This paper distinguishes two categories of questions that the Price equation can help us answer. The two different types of questions require two different disciplines that are related, but nonetheless move in opposite directions. These disciplines are probability theory on the one hand and statistical inference on the other. In the literature on the Price equation this distinction is not made. As a result of this, questions that require a probability model are regularly approached with statistical tools. In this paper, we examine the possibilities of the Price equation for answering questions of either type. By spending extra attention on mathematical formalities, we avoid the two disciplines to get mixed up. After that, we look at some examples, both from kin selection and from group selection, that show how the inappropriate use of statistical terminology can put us on the wrong track. Statements that are 'derived' with the help of the Price equation are, therefore, in many cases not the answers they seem to be. Going through the derivations in reverse can, however, be helpful as a guide how to build proper (probabilistic) models that do give answers.}, } @article {pmid15910322, year = {2005}, author = {Trontti, K and Aron, S and Sundström, L}, title = {Inbreeding and kinship in the ant Plagiolepis pygmaea.}, journal = {Molecular ecology}, volume = {14}, number = {7}, pages = {2007-2015}, doi = {10.1111/j.1365-294X.2005.02529.x}, pmid = {15910322}, issn = {0962-1083}, mesh = {Animals ; Ants/*genetics/physiology ; France ; Gene Frequency ; *Genetic Variation ; *Genetics, Population ; Genotype ; *Inbreeding ; Microsatellite Repeats/genetics ; Population Dynamics ; Sexual Behavior, Animal/physiology ; Species Specificity ; }, abstract = {In ants the presence of multiple reproductive queens (polygyny) decreases the relatedness among workers and the brood they rear, and subsequently dilutes their inclusive fitness benefits from helping. However, adoption of colony daughters, low male dispersal in conjunction with intranidal (within nest) mating and colony reproduction by budding may preserve local genetic differences, and slow down the erosion of relatedness. Reduced dispersal and intranidal mating may, however, also lead to detrimental effects owing to competition and inbreeding. We studied mating and dispersal patterns, and colony kinship in three populations of the polygynous ant Plagiolepis pygmaea using microsatellite markers. We found that the populations were genetically differentiated, but also a considerable degree of genetic structuring within populations. The genetic viscosity within populations can be attributed to few genetically homogeneous colony networks, which presumably have arisen through colony reproduction by budding. Hence, selection may act at different levels, the individuals, the colonies and colony networks. All populations were also significantly inbred (F=0.265) suggesting high frequencies of intranidal mating and low male dispersal. Consequently the mean regression relatedness among workers was significantly higher (r = 0.529-0.546) than would be expected under the typically reported number (5-35) of queens in nests of the species. Furthermore, new queens were mainly recruited from their natal or a neighbouring related colony. Finally, the effective number of queens coincided with that found upon excavation, suggesting low reproductive skew.}, } @article {pmid15889344, year = {2005}, author = {Dilworth, C}, title = {The selfish karyotype. An analysis of the biological basis of morals.}, journal = {Rivista di biologia}, volume = {98}, number = {1}, pages = {125-154}, pmid = {15889344}, issn = {0035-6050}, mesh = {*Altruism ; *Biological Evolution ; Cooperative Behavior ; *Genetics, Behavioral ; Humans ; Karyotyping ; *Morals ; Social Behavior ; }, abstract = {An analysis is made of the kin-selection/group-selection debate on the issue of the biological basis of morals. The kin-selection view sees altruism, and morals in the case of humans, as resting solely on genetic factors; in fact, on this view, evolution itself is to take place only through genetic change -- a position which cannot be reconciled with our knowledge that species evolution involves karyotypic change. Morality is thought to stem from a particular gene which at one time was completely absent from the human population but which later entered and spread through it. On the generally accepted conception of kin selection, this 'altruistic' gene is to be responsible not only for apparently altruistic behaviour towards near relatives, but also for parental care. Thus this view, among other things, has the absurd consequence that there was a period directly after humans first came into existence during which we did not care for our young. In contrast, the group-selection view, as developed here, sees morality as stemming from the species' karyotype, and to be passed on karyotypically from species to species through evolution. As suggested by Darwin, morality is thus derived from our social instincts, and is fundamentally directed to members of one's tribe or community, not to members of one's family. In keeping with this perspective, it is suggested here that the biological basis of morals does not concern the continuation of each individual's gene line, but the continuing existence of the individual's community, and thus, indirectly, the survival of the human species, through supporting the continuing instantiation of its karyotype.}, } @article {pmid15858573, year = {2005}, author = {Sharp, SP and McGowan, A and Wood, MJ and Hatchwell, BJ}, title = {Learned kin recognition cues in a social bird.}, journal = {Nature}, volume = {434}, number = {7037}, pages = {1127-1130}, doi = {10.1038/nature03522}, pmid = {15858573}, issn = {1476-4687}, mesh = {Animals ; *Cooperative Behavior ; *Cues ; Female ; Learning/*physiology ; Male ; Nesting Behavior/physiology ; Pair Bond ; *Pedigree ; Reproduction/physiology ; Seasons ; Songbirds/*physiology ; United Kingdom ; Vocalization, Animal/*physiology ; }, abstract = {In many cooperatively breeding birds, kin selection has an important role in the evolution and maintenance of social behaviour, and 'helpers' can maximize indirect fitness gains by preferentially allocating care to close relatives. Although there is evidence for kin-biased helping behaviour in several species, the mechanism of kin recognition underlying this behaviour is poorly understood. Vocalizations are the most commonly used cues in avian recognition systems, but the effectiveness of vocal signals as reliable recognition cues must depend on how they are acquired. However, there have been no experimental studies of the development of vocal recognition cues in cooperative birds; indeed, the ontogeny of all bird vocalizations other than song is poorly known in any species. Here, we show that cooperatively breeding long-tailed tits (Aegithalos caudatus) can discriminate between kin and non-kin according to the individual-specific characteristics of contact calls, and show experimentally that individuals learn these calls from provisioning adults during the nestling period. Finally, we show that the pattern of cooperative behaviour in this species is consistent with the use of recognition cues learned through association.}, } @article {pmid15842480, year = {2005}, author = {Long, TA}, title = {The influence of mating system on the intensity of parent-offspring conflict in primates.}, journal = {Journal of evolutionary biology}, volume = {18}, number = {3}, pages = {509-515}, doi = {10.1111/j.1420-9101.2005.00888.x}, pmid = {15842480}, issn = {1010-061X}, mesh = {Animals ; *Biological Evolution ; Body Size ; *Conflict, Psychological ; Female ; Fetus/physiology ; Male ; Maternal Behavior ; *Models, Biological ; Paternal Behavior ; Placenta/physiology ; Primates/*physiology ; *Selection, Genetic ; Sexual Behavior, Animal/*physiology ; *Social Behavior ; }, abstract = {An evolutionary conflict of interest exists between parents and their offspring over the partitioning of parental investment (PI) among siblings. When the direct fitness benefits to offspring of increased PI, outweigh the inclusive fitness costs from lost future sibling fitness, selection should favour the evolution of offspring selfishness over altruism. In theory, this conflict is heightened when females are not strictly monogamous, as current offspring should be less altruistic towards future half-siblings than they would be towards full-siblings. Using data collected on foetal growth rate (representing prenatal PI) in primates, I test the prediction from theory that the resolution of the parent-offspring conflict will be closer to the offspring's evolutionary optima in polyandrous species than in more monandrous species. Using phylogenetic comparative analysis, and controlling for allometry, I show that offspring are able to obtain more PI when the probability of future full-siblings decreases, and that this is most pronounced in taxa where there is the opportunity for direct foetal access to the maternal bloodstream. These results support the hypothesis that the resolution of prenatal PI conflict is influenced by both a species' mating system and by its placental structure.}, } @article {pmid15801618, year = {2004}, author = {Saigo, T and Tsuchida, K}, title = {Queen and worker policing in monogynous and monandrous colonies of a primitively eusocial wasp.}, journal = {Proceedings. Biological sciences}, volume = {271 Suppl 6}, number = {Suppl 6}, pages = {S509-12}, pmid = {15801618}, issn = {0962-8452}, mesh = {Animals ; Female ; *Hierarchy, Social ; Microsatellite Repeats/genetics ; Observation ; Reproduction/genetics/physiology ; Sex Ratio ; Sexual Behavior, Animal/*physiology ; *Social Behavior ; Wasps/genetics/*physiology ; }, abstract = {Kin-selection theory predicts that a worker prefers to produce her own sons in a colony with monandry and monogyny because relatedness to her sons (0.5) and nephews (0.375) exceeds that to brothers (0.25). In spite of this prediction, recent studies reveal that workers police each other (mutual-worker egg removal) even in monandrous and monogynous colonies. We conducted field and laboratory studies to evaluate queen and worker policing in queen-right colonies of the primitively eusocial wasp Polistes chinensis antennalis. Genetic studies using microsatellite markers, as well as extensive observations of natural colonies, revealed that both queen and workers removed both queen- and worker-laid eggs in monogynous and monandrous colonies. The queen's eggs survived to hatching more successfully than those of the workers (88.5% versus 1.4%). We discuss the likely factors to explain these worker-policing behaviours.}, } @article {pmid15792223, year = {2005}, author = {Billiard, S and Lenormand, T}, title = {Evolution of migration under kin selection and local adaptation.}, journal = {Evolution; international journal of organic evolution}, volume = {59}, number = {1}, pages = {13-23}, pmid = {15792223}, issn = {0014-3820}, mesh = {*Adaptation, Biological ; *Animal Migration ; Biological Evolution ; Competitive Behavior ; Environment ; Linkage Disequilibrium ; *Models, Genetic ; Stochastic Processes ; }, abstract = {We present here a stochastic two-locus, two-habitat model for the evolution of migration with local adaptation and kin selection. One locus determines the migration rate while the other causes local adaptation. We show that the opposing forces of kin competition and local adaptation can lead to the existence of one or two convergence stable migration rates, notably depending on the recombination rate between the two loci. We show that linkage between migration and local adaptation loci has two antagonist effects: when linkage is tight, cost of local adaptation increases, leading to smaller equilibrium migration rates. However, when linkage is tighter, the population structure at the migration locus tends to be very high because of the indirect selection, and thus equilibrium migration rates increases. This result, qualitatively different from results obtained with other models of migration evolution, indicates that ignoring drift or the detail of the genetic architecture may lead to incorrect conclusions.}, } @article {pmid15772661, year = {2005}, author = {Bowles, S and Posel, D}, title = {Genetic relatedness predicts South African migrant workers' remittances to their families.}, journal = {Nature}, volume = {434}, number = {7031}, pages = {380-383}, doi = {10.1038/nature03420}, pmid = {15772661}, issn = {1476-4687}, mesh = {Age Factors ; *Altruism ; Cost-Benefit Analysis ; Data Collection ; *Family ; Family Characteristics ; Female ; Humans ; Income/*statistics & numerical data ; Male ; *Models, Biological ; Parents ; *Pedigree ; Reproduction ; Sex Factors ; South Africa ; Transients and Migrants/*statistics & numerical data ; }, abstract = {Inclusive fitness models predict many commonly observed behaviours: among humans, studies of within-household violence, the allocation of food and child care find that people favour those to whom they are more closely related. In some cases however, kin-altruism effects appear to be modest. Do individuals favour kin to the extent that kin-altruism models predict? Data on remittances sent by South African migrant workers to their rural households of origin allow an explicit test, to our knowledge the first of its kind for humans. Using estimates of the fitness benefits and costs associated with the remittance, the genetic relatedness of the migrant to the beneficiaries of the transfer, and their age- and sex-specific reproductive values, we estimate the level of remittance that maximizes the migrant worker's inclusive fitness. This is a much better predictor of observed remittances than is average relatedness, even when we take account (by means of a multiple regression) of covarying influences on the level of remittance. But the effect is modest: less than a third of the observed level of remittances can be explained by our kin-altruism model.}, } @article {pmid15744300, year = {2005}, author = {Krakauer, AH}, title = {Kin selection and cooperative courtship in wild turkeys.}, journal = {Nature}, volume = {434}, number = {7029}, pages = {69-72}, doi = {10.1038/nature03325}, pmid = {15744300}, issn = {1476-4687}, mesh = {Altruism ; Animals ; Animals, Wild/*physiology ; Biological Evolution ; *Cooperative Behavior ; *Courtship ; Female ; Genotype ; Male ; Microsatellite Repeats/genetics ; Models, Biological ; Reproduction/physiology ; *Selection, Genetic ; Sexual Behavior, Animal/*physiology ; Turkeys/*physiology ; }, abstract = {In the few species of birds in which males form display partnerships to attract females, one male secures most or all of the copulations. This leads to the question of why subordinate males help in the absence of observable reproductive benefits. Hamilton's concept of kin selection, whereby individuals can benefit indirectly by helping a relative, was a crucial breakthrough for understanding apparently altruistic systems. However in the only direct test of kin selection in coordinated display partnerships, partners were unrelated, discounting kin selection as an explanation for the evolution of cooperation. Here I show, using genetic measures of relatedness and reproductive success, that kin selection can explain the evolution of cooperative courtship in wild turkeys. Subordinate (helper) males do not themselves reproduce, but their indirect fitness as calculated by Hamilton's rule more than offsets the cost of helping. This result confirms a textbook example of kin selection that until now has been controversial and also extends recent findings of male relatedness on avian leks by quantifying the kin-selected benefits gained by non-reproducing males.}, } @article {pmid15734690, year = {2005}, author = {Preston, BT and Stevenson, IR and Pemberton, JM and Coltman, DW and Wilson, K}, title = {Male mate choice influences female promiscuity in Soay sheep.}, journal = {Proceedings. Biological sciences}, volume = {272}, number = {1561}, pages = {365-373}, pmid = {15734690}, issn = {0962-8452}, mesh = {Animals ; Body Size ; Body Weights and Measures ; Competitive Behavior/physiology ; Female ; Male ; Observation ; Reproduction/*physiology ; Scotland ; *Selection, Genetic ; Sex Factors ; Sexual Behavior, Animal/*physiology ; Sheep/*physiology ; Spermatozoa/*physiology ; }, abstract = {In most animal species, males are predicted to compete for reproductive opportunities, while females are expected to choose between potential mates. However, when males' rate of reproduction is constrained, or females vary widely in 'quality', male mate choice is also predicted to occur. Such conditions exist in the promiscuous mating system of feral Soay sheep on St Kilda, Scotland, where a highly synchronized mating season, intense sperm competition and limitations on sperm production constrain males' potential reproductive rate, and females vary substantially in their ability to produce successful offspring. We show that, consistent with predictions, competitive rams focus their mating activity and siring success towards heavier females with higher inclusive fitness. To our knowledge, this is the first time that male mate choice has been identified and shown to lead to assortative patterns of parentage in a natural mammalian system, and occurs despite fierce male-male competition for mates. An additional consequence of assortative mating in this population is that lighter females experience a series of unstable consorts with less adept rams, and hence are mated by a greater number of males during their oestrus. We have thus also identified a novel male-driven mechanism that generates variation in female promiscuity, which suggests that the high levels of female promiscuity in this system are not part of an adaptive female tactic to intensify post-copulatory competition between males.}, } @article {pmid15677714, year = {2005}, author = {Hammel, EA}, title = {Demographic dynamics and kinship in anthropological populations.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {102}, number = {6}, pages = {2248-2253}, pmid = {15677714}, issn = {0027-8424}, mesh = {Data Interpretation, Statistical ; *Demography ; *Family ; Fertility ; Humans ; Models, Theoretical ; *Population ; }, abstract = {Changes in fertility and mortality affect the size of surviving sibling sets and thus numbers of surviving kin. Because the genealogical generations specifying kinship relations are not temporal cohorts and most plausible demographic changes in anthropological populations are period shocks, the effect of such shocks on kin counts are complex. Shocks increasing fertility or decreasing mortality produce larger numbers of kin per ego and decrease the inequality of the distribution of kin and vice versa. Effects are more diffuse at more distant collateral ranges. Effects are stronger the more intense the shock and the longer its duration. Kinship distributions return to their initial state after the shock and as the original age structure of the population is ergodically reattained. Alternating shocks produce more complex patterns. Implications of these outcomes are that opportunities for political networking and consolidation by means of kinship are altered by demographic instabilities, as are the dynamics of kin selection. This analysis is limited for simplicity to unilineal agnatic reckoning of kin.}, } @article {pmid19325857, year = {2007}, author = {Abedon, ST and Lejeune, JT}, title = {Why bacteriophage encode exotoxins and other virulence factors.}, journal = {Evolutionary bioinformatics online}, volume = {1}, number = {}, pages = {97-110}, pmid = {19325857}, issn = {1176-9343}, abstract = {This study considers gene location within bacteria as a function of genetic element mobility. Our emphasis is on prophage encoding of bacterial virulence factors (VFs). At least four mechanisms potentially contribute to phage encoding of bacterial VFs: (i) Enhanced gene mobility could result in greater VF gene representation within bacterial populations. We question, though, why certain genes but not others might benefit from this mobility. (ii) Epistatic interactions-between VF genes and phage genes that enhance VF utility to bacteria-could maintain phage genes via selection acting on individual, VF-expressing bacteria. However, is this mechanism sufficient to maintain the rest of phage genomes or, without gene co-regulation, even genetic linkage between phage and VF genes? (iii) Phage could amplify VFs during disease progression by carrying them to otherwise commensal bacteria colocated within the same environment. However, lytic phage kill bacteria, thus requiring assumptions of inclusive fitness within bacterial populations to explain retention of phage-mediated VF amplification for the sake of bacterial utility. Finally, (iv) phage-encoded VFs could enhance phage Darwinian fitness, particularly by acting as ecosystem-modifying agents. That is, VF-supplied nutrients could enhance phage growth by increasing the density or by improving the physiology of phage-susceptible bacteria. Alternatively, VF-mediated break down of diffusion-inhibiting spatial structure found within the multicellular bodies of host organisms could augment phage dissemination to new bacteria or to environments. Such phage-fitness enhancing mechanisms could apply particularly given VF expression within microbiologically heterogeneous environments, ie, ones where phage have some reasonable potential to acquire phage-susceptible bacteria.}, } @article {pmid15590617, year = {2004}, author = {Stake, JE}, title = {The property 'instinct'.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {359}, number = {1451}, pages = {1763-1774}, pmid = {15590617}, issn = {0962-8436}, mesh = {Animals ; Behavior/physiology ; Biological Evolution ; Family ; Female ; Gender Identity ; Humans ; Instinct ; Male ; Ownership/*legislation & jurisprudence ; }, abstract = {Evolutionary theory and empirical studies suggest that many animals, including humans, have a genetic predisposition to acquire and retain property. This is hardly surprising because survival is closely bound up with the acquisition of things: food, shelter, tools and territory. But the root of these general urges may also run to quite specific and detailed rules about property acquisition, retention and disposition. The great variation in property-related behaviours across species may mask some important commonalities grounded in adaptive utility. Experiments and observations in the field and laboratory suggest that the legal rules of temporal priority and possession are grounded in what were evolutionarily stable strategies in the ancestral environment. Moreover, the preferences that humans exhibit in disposing of their property on their deaths, both by dispositions made in wills and by the laws of intestacy, tend to advance reproductive success as a result of inclusive fitness pay-offs.}, } @article {pmid15560908, year = {2004}, author = {Lessard, S and Rocheleau, G}, title = {Kin selection and coefficients of relatedness in family-structured populations with inbreeding.}, journal = {Theoretical population biology}, volume = {66}, number = {4}, pages = {287-306}, doi = {10.1016/j.tpb.2004.05.004}, pmid = {15560908}, issn = {0040-5809}, mesh = {Animals ; *Inbreeding ; Population Dynamics ; Reproduction/genetics ; Selection, Genetic ; }, abstract = {We consider family specific fitnesses that depend on mixed strategies of two basic phenotypes or behaviours. Pairwise interactions are assumed, but they are restricted to occur between sibs. To study the change in frequency of a rare mutant allele, we consider two different forms of weak selection, one applied through small differences in genotypic values determining individual mixed strategies, the other through small differences in viabilities according to the behaviours chosen by interacting sibs. Under these two specific forms of weak selection, we deduce conditions for initial increase in frequency of a rare mutant allele for autosomal genes in the partial selfing model as well as autosomal and sex-linked genes in the partial sib-mating model with selection before mating or selection after mating. With small differences in mixed strategies, we show that conditions for protection of a mutant allele are tantamount to conditions for initial increase in frequency obtained in additive kin selection models. With particular reference to altruism versus selfishness, we provide explicit ranges of values for the selfing or sib-mating rate based on a fixed cost-benefit ratio and the dominance scheme that allow the spreading of a rare mutant allele into the population. This study confirms that more inbreeding does not necessarily promote the evolution of altruism. Under the hypothesis of small differences in viabilities, the situation is much more intricate unless an additive model is assumed. In general however, conditions for initial increase in frequency of a mutant allele can be obtained in terms of fitness effects that depend on the genotypes of interacting individuals or their mates and generalized conditional coefficients of relatedness according to the inbreeding condition of the interacting individuals.}, } @article {pmid15530496, year = {2005}, author = {Yaniv, O and Motro, U}, title = {Time-dependent animal conflicts: 2. The asymmetric case.}, journal = {Journal of theoretical biology}, volume = {232}, number = {2}, pages = {277-284}, doi = {10.1016/j.jtbi.2004.08.012}, pmid = {15530496}, issn = {0022-5193}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; *Conflict, Psychological ; *Game Theory ; Helping Behavior ; Models, Biological ; }, abstract = {This paper presents an asymmetric game-theoretical model to the following type of animal conflicts: a member of a group is at risk and needs the help of another member to be saved. As long as assistance is not provided, this individual has a positive, time-dependent rate of dying. Assisting the individual which is at risk accrues a cost, but losing it decreases each member's inclusive fitness. A potential helper's interval between the moment a group member gets into trouble and the moment it assists is a random variable, hence its strategy is to choose the distribution of this random variable. In the asymmetric conflict all the potential helpers have identical strategy sets, but each plays a different role. For example, male or female and young or old. We consider both payoff-irrelevant asymmetry and payoff-relevant asymmetry and characterize each role's stable replies. The evolutionarily stable strategies (ESS) are computed, and the model is applied to the n brothers' problem. According to our results immediate assistance and no assistance are possible ESS both under payoff-relevant asymmetry and under payoff-relevant asymmetry.}, } @article {pmid15530495, year = {2005}, author = {Yaniv, O and Motro, U}, title = {Time-dependent animal conflicts: 1. The symmetric case.}, journal = {Journal of theoretical biology}, volume = {232}, number = {2}, pages = {261-275}, doi = {10.1016/j.jtbi.2004.08.011}, pmid = {15530495}, issn = {0022-5193}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; *Conflict, Psychological ; *Game Theory ; Helping Behavior ; Models, Biological ; }, abstract = {Animal conflicts are often characterized by time-dependent strategy sets. This paper considers the following type of animal conflicts: a member of a group is at risk and needs the assistance of another member to be saved. As long as assistance is not provided, the individual which is at risk has a positive, time-dependent rate of dying. Each of the other group members is a potential helper. Assisting this individual accrues a cost, but losing him decreases the inclusive fitness of each group member. A potential helper's interval between the moment an individual finds itself at risk and the moment it assists is a random variable, hence its strategy is to choose the probability distribution for this random variable. Assuming that each of the potential helpers knows the others' strategies, we show that the ability to observe their realizations influences the evolutionarily stable strategies (ESS) of the game. According to our results, where the realizations can be observed ESS always exist: immediate assistance, no assistance and delayed assistance. Where the realizations cannot be observed ESS do not always exist, immediate assistance and no assistance are possible ESS, while delayed assistance cannot be an ESS. We apply our model to the n brothers' problem and to the parental investment conflict.}, } @article {pmid15504012, year = {2004}, author = {Mondor, EB and Roitberg, BD}, title = {Inclusive fitness benefits of scent-marking predators.}, journal = {Proceedings. Biological sciences}, volume = {271 Suppl 5}, number = {Suppl 5}, pages = {S341-3}, pmid = {15504012}, issn = {0962-8452}, mesh = {Adaptation, Physiological/*physiology ; Analysis of Variance ; *Animal Communication ; Animals ; Aphids/*physiology ; Coleoptera/*physiology ; Escape Reaction/physiology ; Odorants ; Pheromones/chemistry ; Predatory Behavior/physiology ; *Selection, Genetic ; }, abstract = {Because relatedness is high and dispersal is limited, one would expect to see higher levels of altruistic behaviour among clonal organisms than among animals of lesser relatedness. Enigmatically, however, parthenogenetic aphids do not emit alarm signals when a predator first enters a colony but only after being captured. Here, we report that an aphid smearing alarm pheromone directly onto a predator decreases the predation risk for clone-mates as the predator continues to search for additional prey. Adult multicoloured Asian ladybird beetles, Harmonia axyridis, daubed with alarm pheromone caused a greater proportion of aphids to drop off a plant and escape predation than did predators lacking pheromone droplets. Thus, along with direct fitness benefits of individual protection, aphid alarm signalling behaviour may have evolved through inclusive fitness benefits of protecting clone-mates by scent-marking predators.}, } @article {pmid15446434, year = {2004}, author = {Axelrod, R and Hammond, RA and Grafen, A}, title = {Altruism via kin-selection strategies that rely on arbitrary tags with which they coevolve.}, journal = {Evolution; international journal of organic evolution}, volume = {58}, number = {8}, pages = {1833-1838}, doi = {10.1111/j.0014-3820.2004.tb00465.x}, pmid = {15446434}, issn = {0014-3820}, mesh = {*Altruism ; *Biological Evolution ; Computer Simulation ; *Models, Genetic ; *Selection, Genetic ; Social Environment ; }, abstract = {Hamilton's rule explains when natural selection will favor altruism between conspecifics, given their degree of relatedness. In practice, indicators of relatedness (such as scent) coevolve with strategies based on these indicators, a fact not included in previous theories of kin recognition. Using a combination of simulation modeling and mathematical extension of Hamilton's rule, we demonstrate how altruism can emerge and be sustained in a coevolutionary setting where relatedness depends on an individual's social environment and varies from one locus to another. The results support a very general expectation of widespread, and not necessarily weak, conditional altruism in nature.}, } @article {pmid15368599, year = {2004}, author = {Tymicki, K}, title = {Kin influence on female reproductive behavior: the evidence from reconstitution of the Bejsce parish registers, 18th to 20th centuries, Poland.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {16}, number = {5}, pages = {508-522}, doi = {10.1002/ajhb.20059}, pmid = {15368599}, issn = {1042-0533}, mesh = {Cohort Studies ; Developed Countries ; Family Characteristics ; Female ; *Fertility ; History, 18th Century ; History, 19th Century ; History, 20th Century ; Humans ; Poland ; *Population Dynamics ; Proportional Hazards Models ; Registries ; Regression Analysis ; *Reproductive History ; }, abstract = {The phenomenon of kin-oriented help, according to inclusive fitness theory, should be of crucial importance with respect to the process of reproduction. This is due to the fact that the devoted time and resources might indirectly contribute to the reproductive performance of a donor. This study aimed at analyzing the kin effects on fertility in order to check whether help received from kinsmen enhance a recipient's reproduction in terms of parity transition risk, completed fertility, and the number of survivors. The data came from reconstitution of church registers from Bejsce parish, Poland. To estimate the kin effect, regression models for count outcomes and techniques of multilevel event history analysis were applied. The analyses have shown that completed fertility and parity-specific transition risks are strongly influenced by various kin groups. Moreover, a multilevel hazard model revealed differences in the patterns of the kin influence among controlled fertility than among natural fertility birth cohorts. Female reproductive outcome is influenced mainly by the presence of siblings and postreproductive helpers (grandparents). However, there is a negative impact of so-called helpers-at-the-nest (older children in the household) on parity transition risks.}, } @article {pmid15355244, year = {2005}, author = {Tallamy, DW}, title = {Egg dumping in insects.}, journal = {Annual review of entomology}, volume = {50}, number = {}, pages = {347-370}, doi = {10.1146/annurev.ento.50.071803.130424}, pmid = {15355244}, issn = {0066-4170}, mesh = {Animals ; Behavior, Animal/*physiology ; Biological Evolution ; Female ; Host-Parasite Interactions ; Insecta/*physiology ; Oviposition/*physiology ; }, abstract = {Females that place eggs under the care of conspecifics have been labeled egg dumpers. Egg dumping is an effective reproductive alternative that lowers risks for, and has the potential to increase fecundity in, its practitioners. Although insect egg dumpers can be social parasites of the maternal behavior of egg recipients, dumping is more likely to be a viable reproductive alternative when the costs to egg recipients are low and thus the defense by potential hosts against egg dumping intrusions is minimal. These conditions are met in insects that guard only eggs or in insects whose eggs hatch into self-supporting precocial young that need little beyond defense from parents. When this is the case, egg dumping is favored by natural and/or kin selection as a mechanism by which dumpers can avoid parental risks and increase fecundity, and egg recipients can enhance offspring survival by diluting predation.}, } @article {pmid15329720, year = {2004}, author = {Griffin, AS and West, SA and Buckling, A}, title = {Cooperation and competition in pathogenic bacteria.}, journal = {Nature}, volume = {430}, number = {7003}, pages = {1024-1027}, doi = {10.1038/nature02744}, pmid = {15329720}, issn = {1476-4687}, mesh = {Altruism ; Analysis of Variance ; *Biological Evolution ; Competitive Behavior ; Cooperative Behavior ; Host-Parasite Interactions ; Humans ; *Models, Biological ; Pseudomonas aeruginosa/classification/genetics/*pathogenicity/*physiology ; Siderophores/*biosynthesis ; Virulence ; }, abstract = {Explaining altruistic cooperation is one of the greatest challenges for evolutionary biology. One solution to this problem is if costly cooperative behaviours are directed towards relatives. This idea of kin selection has been hugely influential and applied widely from microorganisms to vertebrates. However, a problem arises if there is local competition for resources, because this leads to competition between relatives, reducing selection for cooperation. Here we use an experimental evolution approach to test the effect of the scale of competition, and how it interacts with relatedness. The cooperative trait that we examine is the production of siderophores, iron-scavenging agents, in the pathogenic bacterium Pseudomonas aeruginosa. As expected, our results show that higher levels of cooperative siderophore production evolve in the higher relatedness treatments. However, our results also show that more local competition selects for lower levels of siderophore production and that there is a significant interaction between relatedness and the scale of competition, with relatedness having less effect when the scale of competition is more local. More generally, the scale of competition is likely to be of particular importance for the evolution of cooperation in microorganisms, and also the virulence of pathogenic microorganisms, because cooperative traits such as siderophore production have an important role in determining virulence.}, } @article {pmid15312076, year = {2004}, author = {Wenseleers, T and Helanterä, H and Hart, A and Ratnieks, FL}, title = {Worker reproduction and policing in insect societies: an ESS analysis.}, journal = {Journal of evolutionary biology}, volume = {17}, number = {5}, pages = {1035-1047}, doi = {10.1111/j.1420-9101.2004.00751.x}, pmid = {15312076}, issn = {1010-061X}, mesh = {Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; Hymenoptera/*physiology ; *Models, Biological ; Reproduction/physiology ; *Social Dominance ; }, abstract = {Insect societies are vulnerable to exploitation by workers who reproduce selfishly rather than help to rear the queen's offspring. In most species, however, only a small proportion of the workers reproduce. Here, we develop an evolutionarily stable strategy (ESS) model to investigate factors that could explain these observed low levels of reproductive exploitation. Two key factors are identified: relatedness and policing. Relatedness affects the ESS proportion of reproductive workers because laying workers generally work less, leading to greater inclusive fitness costs when within-colony relatedness is higher. The second key factor is policing. In many species, worker-laid eggs are selectively removed or 'policed' by other workers or the queen. We show that policing not only prevents the rearing of worker-laid eggs but can also make it unprofitable for workers to lay eggs in the first place. This can explain why almost no workers reproduce in species with efficient policing, such as honeybees, Apis, and the common wasp, Vespula vulgaris, despite relatively low relatedness caused by multiple mating of the mother queen. Although our analyses focus on social insects, the conclusion that both relatedness and policing can reduce the incentive for cheating applies to other biological systems as well.}, } @article {pmid15312074, year = {2004}, author = {Hodgson, DJ and Hitchman, RB and Vanbergen, AJ and Hails, RS and Possee, RD and Cory, JS}, title = {Host ecology determines the relative fitness of virus genotypes in mixed-genotype nucleopolyhedrovirus infections.}, journal = {Journal of evolutionary biology}, volume = {17}, number = {5}, pages = {1018-1025}, doi = {10.1111/j.1420-9101.2004.00750.x}, pmid = {15312074}, issn = {1010-061X}, mesh = {Animals ; *Ecosystem ; Electrophoresis ; Genotype ; Larva/physiology/virology ; Linear Models ; *Models, Genetic ; Moths/genetics/physiology/*virology ; Nucleopolyhedroviruses/*genetics/*pathogenicity ; Polymorphism, Restriction Fragment Length ; Scotland ; Time Factors ; }, abstract = {Mixed-genotype infections are common in many natural host-parasite interactions. Classical kin-selection models predict that single-genotype infections can exploit host resources prudently to maximize fitness, but that selection favours rapid exploitation when co-infecting genotypes share limited host resources. However, theory has outpaced evidence: we require empirical studies of pathogen genotypes that naturally co-infect hosts. Do genotypes actually compete within hosts? Can host ecology affect the outcome of co-infection? We posed both questions by comparing traits of infections in which two baculovirus genotypes were fed to hosts alongside inocula of the same or a different genotype. The host, Panolis flammea, is a herbivore of Pinus sylvestris and Pi. contorta. The pathogen, PfNPV (a nucleopolyhedrovirus), occurs naturally as mixtures of genotypes that differ, when isolated, in pathogenicity, speed of kill and yield. Single-genotype infection traits failed to predict the 'winning' genotypes in co-infections. Co-infections infected and caused lethal disease in more hosts, and produced high yields, relative to single-genotype infections. The need to share with nonkin did not cause fitness costs to either genotype. In fact, in hosts feeding on Pi. sylvestris, one genotype gained increased yields in mixed-genotype infections. These results are discussed in relation to theory surrounding adaptive responses to competition with nonkin for limited resources.}, } @article {pmid15295600, year = {2004}, author = {Giron, D and Dunn, DW and Hardy, IC and Strand, MR}, title = {Aggression by polyembryonic wasp soldiers correlates with kinship but not resource competition.}, journal = {Nature}, volume = {430}, number = {7000}, pages = {676-679}, doi = {10.1038/nature02721}, pmid = {15295600}, issn = {1476-4687}, mesh = {Aggression/*physiology ; Altruism ; Animals ; Competitive Behavior/*physiology ; Female ; Heredity/*physiology ; Larva/growth & development/physiology ; Male ; Pedigree ; Reproduction/physiology ; Sex Characteristics ; Sex Ratio ; Wasps/*embryology/growth & development/*physiology ; }, abstract = {Kin selection theory predicts that individuals will show less aggression and more altruism towards relatives. However, recent theoretical developments suggest that with limited dispersal, competition between relatives can override the effects of relatedness. The predicted and opposing influences of relatedness and competition are difficult to approach experimentally because conditions that increase average relatedness among individuals also tend to increase competition. Polyembryonic wasps in the family Encyrtidae are parasites whose eggs undergo clonal division to produce large broods. These insects have also evolved a caste system: some embryos in a clone develop into reproductive larvae that mature into adults, whereas others develop into sterile soldier larvae that defend siblings from competitors. In a brood from a single egg, reproductive altruism by soldiers reflects clone-level allocation to defence at the cost of reproduction, with no conflict between individuals. When multiple eggs are laid into a host, inter-clone conflicts of interest arise. Here we report that soldier aggression in Copidosoma floridanum is inversely related to the genetic relatedness of competitors but shows no correlation with the level of resource competition.}, } @article {pmid15288352, year = {2004}, author = {Brown, WM and Consedine, NS}, title = {Just how happy is the happy puppet? An emotion signaling and kinship theory perspective on the behavioral phenotype of children with Angelman syndrome.}, journal = {Medical hypotheses}, volume = {63}, number = {3}, pages = {377-385}, doi = {10.1016/j.mehy.2004.05.010}, pmid = {15288352}, issn = {0306-9877}, support = {1P20 CA 91372/CA/NCI NIH HHS/United States ; 2SO6 GM54650/GM/NIGMS NIH HHS/United States ; KO7 AG00921/AG/NIA NIH HHS/United States ; }, mesh = {Adult ; *Affect ; Angelman Syndrome/*genetics/*psychology ; Child ; Child Behavior/*psychology ; Child, Preschool ; Clinical Trials as Topic ; Family/psychology ; Female ; Genomic Imprinting/*genetics ; Humans ; Infant ; Infant, Newborn ; Male ; *Models, Genetic ; *Models, Psychological ; Object Attachment ; *Parent-Child Relations ; Phenotype ; }, abstract = {The favored level of parental investment in a child may differ for genes of maternal and paternal origin in the child. This conflict can be expressed in the phenomenon of genomic imprinting that refers to situations in which the same gene is differentially expressed depending on its parent of origin. Two disorders that show the effects of genomic imprinting--both at 15q11-q13--are Angelman Syndrome (AS) which is due to the absence of expression of maternally-inherited genes and Prader-Willi syndromes (PWS) which is due to the absence of expression of paternally-inherited genes. However, although both disorders can arise from the deletion of the same genetic region, the gustatory, behavioral, and affective characteristics of AS and PWS children are remarkably distinct. Recent research inspired by kinship theory has suggested the origins of these phenotypic differences may lie in the differential investment of each parent's genome in the AS or PWS child. Specifically, it is thought that each set of parental genes have different 'ideas' regarding how the child should behave towards the mother and how much investment they should look to extract. In normal cases, the trade-off between the competing parental genomes produces a behavioral equilibrium in the child. However, in pathological instances, particularly where gene expression is one-sided, the evolved behavioral strategies favored by the contributing genome will dominate the child's behavior. To date, research in the area of genomic conflict in AS and PWS children has primarily focusing on differences in post-natal nutrition-related behaviors. The current paper extends this framework by offering an emotion and evolutionary signaling interpretation of the affective characteristics of AS children. A review of the affective characteristics of the two syndromes (PWS and AS) is presented before kinship and emotions theory are used to examine the functions that differential affect expression may serve in altering maternal investment. We expected that because the ultimate goal of paternal genes is to increase the child rearing burden of mothers, the Angelman behavioral phenotype should exhibit the emotion signaling characteristics that elicit levels of investment more consistent with paternal genetic interests. AS children display more positive, relative to negative, affect expressions (i.e. AS children laugh and smile more frequently than PWS children). In affect signaling theories, positive affect signals (i.e., smiling, laughing) have evolved to manipulate the sensory systems of receivers to increase social resources. In contrast, because the expression of some negative affects may indicate to the mother that the infant is not viable, negative affect expression is characteristically low among AS children. However, AS children may nonetheless have high levels of non-expressed anxiety because of its role in assisting the child (and its paternal genome) to maintain vigilance for changes in investment on the part of the mother. Overall, our kinship and emotion signaling analysis of AS children suggests that their global pattern of affect signaling represents one manifestation of an array of possible evolved strategies within the parental genome. Specifically, because AS exhibits the effects of paternally-inherited genes unhindered by the expression of maternally-inherited genes, the AS infant manifests a pattern of expression and non-expression that maximize maternal investment and thus paternal fitness. This theory is a significant departure from the standard but erroneous conjecture that a mother and child's inclusive fitness interests are one and the same.}, } @article {pmid15282605, year = {2004}, author = {Lopez-Vaamonde, C and Koning, JW and Brown, RM and Jordan, WC and Bourke, AF}, title = {Social parasitism by male-producing reproductive workers in a eusocial insect.}, journal = {Nature}, volume = {430}, number = {6999}, pages = {557-560}, doi = {10.1038/nature02769}, pmid = {15282605}, issn = {1476-4687}, mesh = {Aggression/physiology ; Aging/physiology ; Animals ; Bees/genetics/*physiology ; Behavior, Animal/physiology ; Biological Evolution ; Female ; Genotype ; Male ; Microsatellite Repeats/genetics ; Parasites/genetics/*physiology ; Reproduction/*physiology ; *Social Behavior ; }, abstract = {The evolution of extreme cooperation, as found in eusocial insects (those with a worker caste), is potentially undermined by selfish reproduction among group members. In some eusocial Hymenoptera (ants, bees and wasps), workers can produce male offspring from unfertilized eggs. Kin selection theory predicts levels of worker reproduction as a function of the relatedness structure of the workers' natal colony and the colony-level costs of worker reproduction. However, the theory has been only partially successful in explaining levels of worker reproduction. Here we show that workers of a eusocial bumble bee (Bombus terrestris) enter unrelated, conspecific colonies in which they then produce adult male offspring, and that such socially parasitic workers reproduce earlier and are significantly more reproductive and aggressive than resident workers that reproduce within their own colonies. Explaining levels of worker reproduction, and hence the potential of worker selfishness to undermine the evolution of cooperation, will therefore require more than simply a consideration of the kin-selected interests of resident workers. It will also require knowledge of the full set of reproductive options available to workers, including intraspecific social parasitism.}, } @article {pmid15278845, year = {2004}, author = {Roze, D and Rousset, F}, title = {The robustness of Hamilton's rule with inbreeding and dominance: kin selection and fixation probabilities under partial sib mating.}, journal = {The American naturalist}, volume = {164}, number = {2}, pages = {214-231}, doi = {10.1086/422202}, pmid = {15278845}, issn = {1537-5323}, mesh = {*Altruism ; Animals ; Biological Evolution ; Diploidy ; Female ; Gene Frequency ; Genes, Dominant ; Haploidy ; *Inbreeding ; Male ; Models, Biological ; Phenotype ; Population Dynamics ; *Selection, Genetic ; }, abstract = {Assessing the validity of Hamilton's rule when there is both inbreeding and dominance remains difficult. In this article, we provide a general method based on the direct fitness formalism to address this question. We then apply it to the question of the evolution of altruism among diploid full sibs and among haplodiploid sisters under inbreeding resulting from partial sib mating. In both cases, we find that the allele coding for altruism always increases in frequency if a condition of the form rb>c holds, where r depends on the rate of sib mating alpha but not on the frequency of the allele, its phenotypic effects, or the dominance of these effects. In both examples, we derive expressions for the probability of fixation of an allele coding for altruism; comparing these expressions with simulation results allows us to test various approximations often made in kin selection models (weak selection, large population size, large fecundity). Increasing alpha increases the probability of fixation of recessive altruistic alleles (h<1/2), while it can increase or decrease the probability of fixation of dominant altruistic alleles (h>1/2).}, } @article {pmid15255052, year = {2004}, author = {Komdeur, J and Richardson, DS and Burke, T}, title = {Experimental evidence that kin discrimination in the Seychelles warbler is based on association and not on genetic relatedness.}, journal = {Proceedings. Biological sciences}, volume = {271}, number = {1542}, pages = {963-969}, pmid = {15255052}, issn = {0962-8452}, mesh = {Animals ; Association Learning/physiology ; Female ; Genotype ; *Helping Behavior ; Logistic Models ; Microsatellite Repeats/genetics ; Nesting Behavior/*physiology ; Observation ; Recognition, Psychology/*physiology ; Seychelles ; *Social Dominance ; Songbirds/genetics/*physiology ; }, abstract = {In cooperative breeding systems driven by kin selection, effective kin-recognition cues are important. Recognition could be achieved by the direct assessment of the genetic relatedness of individuals or by learning through association. In the Seychelles warbler, Acrocephalus sechellensis, female subordinates maximize indirect fitness by preferentially helping genetically related nestlings. Help seems to be based on the continued presence of the primary female who previously fed the subordinate in the nest but it has, so far, been impossible to discount the direct assessment of genetic relatedness. We used a cross-fostering experiment to separate the two possible cues. Adult birds did not discriminate between their own and cross-fostered eggs or nestlings. Cross-fostering resulted in nestlings that were unrelated to the primary female that raised them, but control nestlings were closely related to their primary females. The proportions of cross-fostered and control female offspring that stayed and became helpers on their 'natal' territory were similar. However, for both groups the chance of becoming a subordinate helper was associated with the continued presence of the primary female and not with any other factor tested. Our study provides strong evidence that helping decisions are based on associative-learning cues.}, } @article {pmid15245410, year = {2004}, author = {Kronauer, DJ and Schoning, C and Pedersen, JS and Boomsma, JJ and Gadau, J}, title = {Extreme queen-mating frequency and colony fission in African army ants.}, journal = {Molecular ecology}, volume = {13}, number = {8}, pages = {2381-2388}, doi = {10.1111/j.1365-294X.2004.02262.x}, pmid = {15245410}, issn = {0962-1083}, mesh = {Animals ; Ants/genetics/*physiology ; Female ; Gene Frequency ; Genotype ; Kenya ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; *Selection, Genetic ; Sexual Behavior, Animal/*physiology ; *Social Behavior ; }, abstract = {Army ants have long been suspected to represent an independent origin of multiple queen-mating in the social Hymenoptera. Using microsatellite markers, we show that queens of the African army ant Dorylus (Anomma) molestus have the highest absolute (17.3) and effective (17.5) queen-mating frequencies reported so far for ants. This confirms that obligate multiple queen-mating in social insects is associated with large colony size and advanced social organization, but also raises several novel questions. First, these high estimates place army ants in the range of mating frequencies of honeybees, which have so far been regarded as odd exceptions within the social Hymenoptera. Army ants and honeybees are fundamentally different in morphology and life history, but are the only social insects known that combine obligate multiple mating with reproduction by colony fission and extremely male-biased sex ratios. This implies that the very high numbers of matings in both groups may be due partly to the relatively low costs of additional matings. Second, we were able to trace recent events of colony fission in four of the investigated colonies, where the genotypes of the two queens were only compatible with a mother-daughter relationship. A direct comparison of male production between colonies with offspring from one and two queens, respectively, suggested strongly that new queens do not produce a sexual brood until all workers of the old queen have died, which is consistent with kin selection theory.}, } @article {pmid15241605, year = {2004}, author = {Korb, J and Heinze, J}, title = {Multilevel selection and social evolution of insect societies.}, journal = {Die Naturwissenschaften}, volume = {91}, number = {6}, pages = {291-304}, pmid = {15241605}, issn = {0028-1042}, mesh = {Animals ; *Biological Evolution ; Female ; Insecta/*classification/*genetics ; Male ; Reproduction ; *Selection, Genetic ; Sexual Behavior, Animal ; *Social Behavior ; }, abstract = {How sterile, altruistic worker castes have evolved in social insects and how they are maintained have long been central topics in evolutionary biology. With the advance of kin selection theory, insect societies, in particular those of haplodiploid bees, ants, and wasps, have become highly suitable model systems for investigating the details of social evolution and recently also how within-group conflicts are resolved. Because insect societies typically do not consist of clones, conflicts among nestmates arise, for example about the partitioning of reproduction and the allocation of resources towards male and female sexuals. Variation in relatedness among group members therefore appears to have a profound influence on the social structure of groups. However, insect societies appear to be remarkably robust against such variation: division of labor and task allocation are often organized in more or less the same way in societies with high as in those with very low nestmate relatedness. To explain the discrepancy between predictions from kin structure and empirical data, it was suggested that constraints-such as the lack of power or information-prevent individuals from pursuing their own selfish interests. Applying a multilevel selection approach shows that these constraints are in fact group-level adaptation preventing or resolving intracolonial conflict. The mechanisms of conflict resolution in insect societies are similar to those at other levels in the biological hierarchy (e.g., in the genome or multicellular organisms): alignment of interests, fair lottery, and social control. Insect societies can thus be regarded as a level of selection with novelties that provide benefits beyond the scope of a solitary life. Therefore, relatedness is less important for the maintenance of insect societies, although it played a fundamental role in their evolution.}, } @article {pmid15232949, year = {2004}, author = {Sachs, JL and Mueller, UG and Wilcox, TP and Bull, JJ}, title = {The evolution of cooperation.}, journal = {The Quarterly review of biology}, volume = {79}, number = {2}, pages = {135-160}, doi = {10.1086/383541}, pmid = {15232949}, issn = {0033-5770}, support = {57756//PHS HHS/United States ; }, mesh = {Algorithms ; Animals ; *Biological Evolution ; Computational Biology ; *Cooperative Behavior ; Humans ; Models, Biological ; Selection, Genetic ; *Sociobiology ; Symbiosis ; }, abstract = {Darwin recognized that natural selection could not favor a trait in one species solely for the benefit of another species. The modern, selfish-gene view of the world suggests that cooperation between individuals, whether of the same species or different species, should be especially vulnerable to the evolution of noncooperators. Yet, cooperation is prevalent in nature both within and between species. What special circumstances or mechanisms thus favor cooperation? Currently, evolutionary biology offers a set of disparate explanations, and a general framework for this breadth of models has not emerged. Here, we offer a tripartite structure that links previously disconnected views of cooperation. We distinguish three general models by which cooperation can evolve and be maintained: (i) directed reciprocation--cooperation with individuals who give in return; (ii) shared genes--cooperation with relatives (e.g., kin selection); and (iii) byproduct benefits--cooperation as an incidental consequence of selfish action. Each general model is further subdivided. Several renowned examples of cooperation that have lacked explanation until recently--plant-rhizobium symbioses and bacteria-squid light organs--fit squarely within this framework. Natural systems of cooperation often involve more than one model, and a fruitful direction for future research is to understand how these models interact to maintain cooperation in the long term.}, } @article {pmid15209109, year = {2004}, author = {Dani, FR and Foster, KR and Zacchi, F and Seppä, P and Massolo, A and Carelli, A and Arévalo, E and Queller, DC and Strassmann, JE and Turillazzi, S}, title = {Can cuticular lipids provide sufficient information for within-colony nepotism in wasps?.}, journal = {Proceedings. Biological sciences}, volume = {271}, number = {1540}, pages = {745-753}, pmid = {15209109}, issn = {0962-8452}, mesh = {Animals ; *Cooperative Behavior ; Discriminant Analysis ; Gas Chromatography-Mass Spectrometry ; Gene Frequency ; Italy ; *Lipid Metabolism ; Lipids/chemistry ; Microsatellite Repeats/genetics ; Multivariate Analysis ; *Odorants ; Population Dynamics ; United Kingdom ; Wasps/*chemistry/genetics/*physiology ; }, abstract = {Inclusive fitness theory predicts that members of non-clonal societies will gain by directing altruistic acts towards their closest relatives. Multiple mating by queens and multiple queens creates distinct full-sister groups in many hymenopteran societies within which nepotism might occur. However, the weight of empirical data suggests that nepotism within full-sister groups is absent. It has been suggested that a lack of reliable recognition markers is responsible. In this paper, we investigated whether epicuticular lipids could provide reliable cues for intracolony kin recognition in two species of social wasps, the paper wasp Polistes dominulus and the hornet Vespa crabro. Epicuticular lipids have previously been shown to be central to kin recognition at the nest level, making them excellent candidates for within-nest discrimination. We genotyped individuals using DNA microsatellites and analysed surface chemistry by gas chromatography-mass spectrometry. We find that in both species epicuticular lipids typically could provide enough information to distinguish related nest-mates from unrelated nest-mates, a difference that occurs in colonies with multiple queens. However, in V. crabro, where colonies may be composed by different patrilines, information for discrimination between full sisters and half-sisters is weaker and prone to errors. Our data suggest that epicuticular lipids at best provide reliable information for intracolony nepotistic discrimination in multiple-queen colonies composed of unrelated lines.}, } @article {pmid15135029, year = {2004}, author = {Fletcher, JA and Zwick, M}, title = {Strong altruism can evolve in randomly formed groups.}, journal = {Journal of theoretical biology}, volume = {228}, number = {3}, pages = {303-313}, doi = {10.1016/j.jtbi.2004.01.004}, pmid = {15135029}, issn = {0022-5193}, mesh = {*Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; *Group Processes ; *Models, Genetic ; }, abstract = {Although the conditions under which altruistic behaviors evolve continue to be vigorously debated, there is general agreement that altruistic traits involving an absolute cost to altruists (strong altruism) cannot evolve when populations are structured with randomly formed groups. This conclusion implies that the evolution of such traits depends upon special environmental conditions or additional organismic capabilities that enable altruists to interact with each other more than would be expected with random grouping. Here we show, using both analytic and simulation results, that the positive assortment necessary for strong altruism to evolve does not require these additional mechanisms, but merely that randomly formed groups exist for more than one generation. Conditions favoring the selection of altruists, which are absent when random groups initially form, can naturally arise even after a single generation within groups-and even as the proportion of altruists simultaneously decreases. The gains made by altruists in a second generation within groups can more than compensate for the losses suffered in the first and in this way altruism can ratchet up to high levels. This is true even if altruism is initially rare, migration between groups allowed, homogeneous altruist groups prohibited, population growth restricted, or kin selection precluded. Until now random group formation models have neglected the significance of multigenerational groups-even though such groups are a central feature of classic "haystack" models of the evolution of altruism. We also explore the important role that stochasticity (effectively absent in the original infinite models) plays in the evolution of altruism. The fact that strong altruism can increase when groups are periodically and randomly formed suggests that altruism may evolve more readily and in simpler organisms than is generally appreciated.}, } @article {pmid15120679, year = {2004}, author = {Jones, D}, title = {The universal psychology of kinship: evidence from language.}, journal = {Trends in cognitive sciences}, volume = {8}, number = {5}, pages = {211-215}, doi = {10.1016/j.tics.2004.03.001}, pmid = {15120679}, issn = {1364-6613}, mesh = {Anthropology ; Classification ; Cross-Cultural Comparison ; Family/*psychology ; Hierarchy, Social ; Humans ; *Language ; *Psycholinguistics ; *Social Environment ; }, abstract = {Kinship is central to social organization in many societies; how people think about kinship should be relevant to social cognition generally. One window onto the mental representation of kinship is afforded by variation and universals in terms for kin. Kin terminologies are commonly organized around binary distinctive features, and terms for some types of kin are consistently linguistically marked. These observations can be formalized in the newly developed framework of linguistic Optimality Theory: permutations in the rank order of a small set of constraints generate basic types of kin terminology without over-generating rare or non-existent types. The result, I argue, is evidence for an innate faculty of social cognition (including several universal schemas of social relationships), apparently shaped by several kinds of genetic kin selection.}, } @article {pmid15070433, year = {2004}, author = {Arévalo, E and Zhu, Y and Carpenter, JM and Strassmann, JE}, title = {The phylogeny of the social wasp subfamily Polistinae: evidence from microsatellite flanking sequences, mitochondrial COI sequence, and morphological characters.}, journal = {BMC evolutionary biology}, volume = {4}, number = {}, pages = {8}, pmid = {15070433}, issn = {1471-2148}, mesh = {Animals ; DNA/chemistry/genetics/isolation & purification ; DNA, Mitochondrial/*genetics ; Electron Transport Complex IV/*genetics ; Microsatellite Repeats/*genetics ; Molecular Sequence Data ; *Phylogeny ; Sequence Analysis, DNA ; Species Specificity ; Wasps/anatomy & histology/classification/*genetics ; }, abstract = {BACKGROUND: Social wasps in the subfamily Polistinae (Hymenoptera: Vespidae) have been important in studies of the evolution of sociality, kin selection, and within colony conflicts of interest. These studies have generally been conducted within species, because a resolved phylogeny among species is lacking. We used nuclear DNA microsatellite flanking sequences, mitochondrial COI sequence, and morphological characters to generate a phylogeny for the Polistinae (Hymenoptera) using 69 species.

RESULTS: Our phylogeny is largely concordant with previous phylogenies at higher levels, and is more resolved at the species level. Our results support the monophyly of the New World subgenera of Polistini, while the Old World subgenera are a paraphyletic group. All genera for which we had more than one exemplar were supported as monophyletic except Polybia which is not resolved, and may be paraphyletic.

CONCLUSION: The combination of DNA sequences from flanks of microsatellite repeats with mtCOI sequences and morphological characters proved to be useful characters establishing relationships among the different subgenera and species of the Polistini. This is the first detailed hypothesis for the species of this important group.}, } @article {pmid15058395, year = {2004}, author = {Olendorf, R and Getty, T and Scribner, K}, title = {Cooperative nest defence in red-winged blackbirds: reciprocal altruism, kinship or by-product mutualism?.}, journal = {Proceedings. Biological sciences}, volume = {271}, number = {1535}, pages = {177-182}, pmid = {15058395}, issn = {0962-8452}, mesh = {Animals ; *Cooperative Behavior ; Male ; Michigan ; Microsatellite Repeats/genetics ; Nesting Behavior/*physiology ; Principal Component Analysis ; *Selection, Genetic ; Songbirds/genetics/*physiology ; }, abstract = {Male red-winged blackbirds (Agelaius phoeniceus) often cooperate with their neighbours in defending nests against predators. Some studies have suggested that this is an example of by-product mutualism, whereas others have suggested the possibility of reciprocal altruism. No study has addressed the possibility of kin-selected cooperation in nest defence in this species. Reciprocal altruism, kin selection and by-product mutualism are not mutually exclusive alternatives, but few studies of territorial neighbours have tested for multiple mechanisms simultaneously. We test for these three possibilities in a population of red-winged blackbirds. We used simulated defections to test for reciprocal altruism. We used analysis of microsatellite loci to test for kin selection between adult male neighbours. We also used microsatellite loci to test for by-product mutualism resulting from nest defence of offspring sired on neighbouring territories. We found that male red-winged blackbirds cooperate in nest defence primarily as a form of reciprocal altruism. Experimental males reduced their level of nest defence relative to controls following simulated defection by a neighbour. In contrast to some earlier studies, we found no evidence for by-product mutualism: males did not defend nests where they had sired extra-pair offspring. We also found no evidence for kin selection: males were no more cooperative with more closely related neighbours. Considered alongside the results from other studies, our study suggests that mechanisms stabilizing cooperation in red-winged blackbirds may vary among populations.}, } @article {pmid15043817, year = {2004}, author = {Bradley, BJ and Doran-Sheehy, DM and Lukas, D and Boesch, C and Vigilant, L}, title = {Dispersed male networks in western gorillas.}, journal = {Current biology : CB}, volume = {14}, number = {6}, pages = {510-513}, doi = {10.1016/j.cub.2004.02.062}, pmid = {15043817}, issn = {0960-9822}, mesh = {Animals ; Central African Republic ; Congo ; Emigration and Immigration ; Gorilla gorilla/*genetics/*physiology ; Male ; Microsatellite Repeats/genetics ; Nesting Behavior/physiology ; *Selection, Genetic ; *Social Dominance ; }, abstract = {Although kin-selection theory has been widely used to explain the tendency of individuals to bias beneficial behaviors towards relatives living within the same social group, less attention has focused on kin-biased interactions between groups. For animal societies in which females emigrate, as is the case for mountain gorillas (Gorilla beringei beringei), encounters between males in different groups often involve aggressive displays that can escalate to physical violence and fatal injuries. However, recent findings on the little-studied western gorilla (Gorilla gorilla) indicate that interactions between social groups occur more frequently than they do in mountain gorillas and are often, although not always, surprisingly nonaggressive. We investigated the pattern of genetic relationships between individuals of different groups and found evidence suggesting a previously unrecognized "dispersed male network" social structure in western gorillas in which the single males leading social groups were usually related to one or more nearby males. We propose that this provides a basis for extra-group, kin-biased behaviors and may explain the reported peaceful intergroup interactions. Furthermore, these results suggest that a patrilocal social structure, in which males remain in their natal region and potentially benefit from kin associations, is a feature unifying African apes and humans.}, } @article {pmid14766187, year = {2004}, author = {Rousset, F and Ronce, O}, title = {Inclusive fitness for traits affecting metapopulation demography.}, journal = {Theoretical population biology}, volume = {65}, number = {2}, pages = {127-141}, doi = {10.1016/j.tpb.2003.09.003}, pmid = {14766187}, issn = {0040-5809}, mesh = {Alleles ; Animals ; Behavior, Animal ; *Genetics, Population ; Humans ; Markov Chains ; *Models, Genetic ; *Population Dynamics ; *Selection, Genetic ; Stochastic Processes ; }, abstract = {Defining computable analytical measures of the effects of selection in populations with demographic and environmental stochasticity is a long-standing problem. We derive an analytical measure which takes in account all consequences of the discrete nature of deme size. Expressions of this measure are detailed for infinite island models of population structure. As an illustration we consider the evolution of dispersal in populations made of small demes with environmental and demographic stochasticity. We confirm some results obtained from the analysis of models based on deterministic approximations. In particular, when there is an Allee effect, we show that evolution of the dispersal rate may lead the metapopulation to extinction. Thus, selection on the dispersal rate could restrict the distribution of species subject to Allee effects. This selection-driven extinction is prevented by kin selection when the environmental extinction rate is small.}, } @article {pmid14666124, year = {2004}, author = {Carlsson, J and Carlsson, JE and Olsén, KH and Hansen, MM and Eriksson, T and Nilsson, J}, title = {Kin-biased distribution in brown trout: an effect of redd location or kin recognition?.}, journal = {Heredity}, volume = {92}, number = {2}, pages = {53-60}, doi = {10.1038/sj.hdy.6800376}, pmid = {14666124}, issn = {0018-067X}, mesh = {Animals ; Behavior, Animal/*physiology ; DNA/analysis ; Denmark ; Gene Frequency ; *Genetics, Population ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; Scotland ; *Selection, Genetic ; Spatial Behavior/*physiology ; Trout/*genetics ; }, abstract = {A wide range of animals have been reported to show kin-biased behaviours, such as reduced aggressiveness and increased food sharing among relatives. However, less is known about whether wild animals also associate with relatives under natural conditions, which is a prerequisite to facilitate kin-biased behaviours and hence kin selection. We tested, by means of microsatellite polymorphism, correlations between pair-wise relatedness and pair-wise metric distance in wild brown trout (Salmo trutta L.) under natural conditions in two streams. Our data show that young-of-the-year as well as older trout found close together also had a higher genetic relatedness in one of the two streams, whereas no relationship was found in the other stream. Very few half and full siblings were found in the second stream and under these conditions it is unlikely that kin-biased behaviours will receive positive selection. We discuss the underlying mechanisms for the observed structure and we specifically address the issue of whether the grouping of related individuals could reflect dispersal from the same spawning redds, or if it reflects active association with relatives, possibly conferring kin-selected advantages.}, } @article {pmid14635900, year = {2003}, author = {Richardson, DS and Burke, T and Komdeurs, J}, title = {Sex-specific associative learning cues and inclusive fitness benefits in the Seychelles warbler.}, journal = {Journal of evolutionary biology}, volume = {16}, number = {5}, pages = {854-861}, doi = {10.1046/j.1420-9101.2003.00592.x}, pmid = {14635900}, issn = {1010-061X}, mesh = {Animals ; *Biological Evolution ; Female ; Genotype ; *Learning ; Male ; Microsatellite Repeats ; Pedigree ; *Sexual Behavior, Animal ; *Songbirds ; }, abstract = {In cooperative breeding vertebrates, indirect fitness benefits would be maximized by subordinates that accurately assess their relatedness to group offspring and preferentially help more closely related kin. In the Seychelles warbler (Acrocephalus sechellensis), we found a positive relationship between subordinate-nestling kinship (determined using microsatellite marker genotypes) and provisioning rates, but only for female subordinates. Female subordinates that helped were significantly more related to the nestlings than were nonhelpers, and the decision to help appears to be based on associative learning cues. High levels of female infidelity means that subordinates cannot trust their legitimacy through the male line, consequently they appear to use the continued presence of the primary female, but not the primary male, as a reliable cue to determine when to feed nestlings. By using effective discrimination, female subordinates are able to maximize the indirect benefits gained within a cooperative breeding system otherwise driven primarily by direct breeding benefits.}, } @article {pmid14635844, year = {2003}, author = {Hammond, RL and Bruford, MW and Bourke, AF}, title = {Male parentage does not vary with colony kin structure in a multiple-queen ant.}, journal = {Journal of evolutionary biology}, volume = {16}, number = {3}, pages = {446-455}, doi = {10.1046/j.1420-9101.2003.00544.x}, pmid = {14635844}, issn = {1010-061X}, mesh = {Animals ; Ants/*physiology ; Biological Evolution ; Female ; Male ; Microsatellite Repeats ; *Models, Biological ; Population Dynamics ; Reproduction/physiology ; *Selection, Genetic ; *Sex Ratio ; Sexual Behavior, Animal/*physiology ; United Kingdom ; }, abstract = {Kin selection theory predicts that, in social Hymenoptera, the parentage of males should be determined by within-colony relatedness. We present a model showing that, when sex ratios are split (bimodal) as a function of colony kin structure, the predictions of kin selection theory regarding the occurrence of worker reproduction and policing (prevention of worker reproduction) require modification. To test the predictions of kin selection theory and our model, we estimated using microsatellites the frequency of worker-produced male eggs and adults in the facultatively polygynous (multiple-queen) ant Leptothorax acervorum. Analysis of 210 male eggs and 328 adult males from 13 monogynous (single-queen) and nine polygynous colonies demonstrated that the frequency of worker-produced males was low (2.3-4.6% of all males) and did not differ significantly between colony classes or between eggs and adults. This suggested workers' self-restraint as the cause of infrequent worker reproduction in both colony classes. Such an outcome is not predicted either by comparing relatedness values or by our model. Therefore, it appears that factors other than colony kin structure and sex ratio effects determine the pattern of male parentage in the study population. A likely factor is a colony-level cost of worker reproduction.}, } @article {pmid14632228, year = {2003}, author = {Wenseleers, T and Ratnieks, FL and Billen, J}, title = {Caste fate conflict in swarm-founding social hymenoptera: an inclusive fitness analysis.}, journal = {Journal of evolutionary biology}, volume = {16}, number = {4}, pages = {647-658}, doi = {10.1046/j.1420-9101.2003.00574.x}, pmid = {14632228}, issn = {1010-061X}, mesh = {Animals ; *Biological Evolution ; Feeding Behavior ; Female ; Hymenoptera/*genetics ; Nutritional Status ; *Sexual Behavior, Animal ; *Social Dominance ; }, abstract = {A caste system in which females develop into morphologically distinct queens or workers has evolved independently in ants, wasps and bees. Although such reproductive division of labour may benefit the colony it is also a source of conflict because individual immature females can benefit from developing into a queen in order to gain greater direct reproduction. Here we present a formal inclusive fitness analysis of caste fate conflict appropriate for swarm-founding social Hymenoptera. Three major conclusions are reached: (1) when caste is self-determined, many females should selfishly choose to become queens and the resulting depletion of the workforce can substantially reduce colony productivity; (2) greater relatedness among colony members reduces this excess queen production; (3) if workers can prevent excess queen production at low cost by controlled feeding, a transition to nutritional caste determination should occur. These predictions generalize results derived earlier using an allele-frequency model [Behav. Ecol. Sociobiol. (2001) 50: 467] and are supported by observed levels of queen production in various taxa, especially stingless bees, where caste can be either individually or nutritionally controlled.}, } @article {pmid14618541, year = {2003}, author = {Lehmann, L and Perrin, N}, title = {Inbreeding avoidance through kin recognition: choosy females boost male dispersal.}, journal = {The American naturalist}, volume = {162}, number = {5}, pages = {638-652}, doi = {10.1086/378823}, pmid = {14618541}, issn = {0003-0147}, mesh = {Animals ; Female ; *Inbreeding ; Male ; *Models, Biological ; Movement/*physiology ; Population Dynamics ; Recognition, Psychology/*physiology ; Reproduction/*physiology ; Selection, Genetic ; Time Factors ; }, abstract = {Inbreeding avoidance is predicted to induce sex biases in dispersal. But which sex should disperse? In polygynous species, females pay higher costs to inbreeding and thus might be expected to disperse more, but empirical evidence consistently reveals male biases. Here, we show that theoretical expectations change drastically if females are allowed to avoid inbreeding via kin recognition. At high inbreeding loads, females should prefer immigrants over residents, thereby boosting male dispersal. At lower inbreeding loads, by contrast, inclusive fitness benefits should induce females to prefer relatives, thereby promoting male philopatry. This result points to disruptive effects of sexual selection. The inbreeding load that females are ready to accept is surprisingly high. In absence of search costs, females should prefer related partners as long as delta
RESULTS: We derive local stability conditions which account for the consequences of small and constant patch size. All results are derived from considering Rm, the overall production of successful emigrants from a patch initially colonized by a single mutant immigrant. Further, the results are interpreted in term of concepts of inclusive fitness theory. The condition for convergence to an evolutionarily stable strategy is proportional to some previous expressions for inclusive fitness. The condition for evolutionary stability stricto sensu takes into account effects of selection on relatedness, which cannot be neglected. It is function of the relatedness between pairs of genes in a neutral model and also of a three-genes relationship. Based on these results, I analyze basic models of dispersal and of competition for resources. In the latter scenario there are cases of global instability despite local stability. The results are developed for haploid island models with constant patch size, but the techniques demonstrated here would apply to more general scenarios with an island mode of dispersal.

CONCLUSIONS: The results allow to identity and to analyze the relative importance of the different selective pressures involved. They bridge the gap between the modelling frameworks that have led to the Rm concept and to inclusive fitness.}, } @article {pmid14582006, year = {2003}, author = {Cadet, C and Ferrière, R and Metz, JA and van Baalen, M}, title = {The evolution of dispersal under demographic stochasticity.}, journal = {The American naturalist}, volume = {162}, number = {4}, pages = {427-441}, doi = {10.1086/378213}, pmid = {14582006}, issn = {0003-0147}, mesh = {*Biological Evolution ; *Ecosystem ; *Environment ; *Models, Biological ; Movement/*physiology ; Population Dynamics ; Selection, Genetic ; Stochastic Processes ; }, abstract = {Temporal and spatial variations of the environment are important factors favoring the evolution of dispersal. With few exceptions, these variations have been considered to be exclusively fluctuations of habitat quality. However, since the presence of conspecifics forms part of an individual's environment, demographic stochasticity may be a component of this variability as well, in particular when local populations are small. To study this effect, we analyzed the evolution of juvenile dispersal in a metapopulation model in which habitat quality is constant in space and time but occupancy fluctuates because of demographic stochasticity. Our analysis extends previous studies in that it includes competition of resources and competition for space. Also, juvenile dispersal is not given by a fixed probability but is made conditional on the presence of free territories in a patch, whereas individuals born in full patches will always disperse. Using a combination of analytical and numerical approaches, we show that demographic stochasticity in itself may provide enough variability to favor dispersal even from patches that are not fully occupied. However, there is no simple relationship between the evolution of dispersal and various indicators of demographic stochasticity. Selected dispersal depends on all aspects of the life-history profile, including kin selection.}, } @article {pmid14576431, year = {2003}, author = {Griffin, AS and West, SA}, title = {Kin discrimination and the benefit of helping in cooperatively breeding vertebrates.}, journal = {Science (New York, N.Y.)}, volume = {302}, number = {5645}, pages = {634-636}, doi = {10.1126/science.1089402}, pmid = {14576431}, issn = {1095-9203}, mesh = {Altruism ; Animals ; *Behavior, Animal ; Birds/*physiology ; Breeding ; *Cooperative Behavior ; Family ; Female ; *Helping Behavior ; Male ; Mammals/*physiology ; Probability ; Sexual Behavior, Animal ; Social Behavior ; Species Specificity ; }, abstract = {In many cooperatively breeding vertebrates, a dominant breeding pair is assisted in offspring care by nonbreeding helpers. A leading explanation for this altruistic behavior is Hamilton's idea that helpers gain indirect fitness benefits by rearing relatives (kin selection). Many studies have shown that helpers typically provide care for relatives, but relatively few have shown that helpers provide closer kin with preferential care (kin discrimination), fueling the suggestion that kin selection only poorly accounts for the evolution of cooperative breeding in vertebrates. We used meta-analysis to show that (i) individuals consistently discriminate between kin, and (ii) stronger discrimination occurs in species where the benefits of helping are greater. These results suggest a general role for kin selection and that the relative importance of kin selection varies across species, as predicted by Hamilton's rule.}, } @article {pmid14561330, year = {2003}, author = {Beekman, M and Ratnieks, FL}, title = {Power over reproduction in social hymenoptera.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {358}, number = {1438}, pages = {1741-1753}, pmid = {14561330}, issn = {0962-8436}, mesh = {Animals ; Hymenoptera/*physiology ; *Power, Psychological ; Reproduction/physiology ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Inclusive fitness theory has been very successful in predicting and explaining much of the observed variation in the reproductive characteristics of insect societies. For example, the theory correctly predicts sex-ratio biasing by workers in relation to the queen's mating frequency. However, within an insect society there are typically multiple reproductive optima, each corresponding to the interest of different individual(s) or parties of interest. When multiple optima occur, which party's interests prevail? Presumably, the interests of the party with the greatest 'power'; the ability to do or act. This article focuses on factors that influence power over colony reproduction. In particular, we seek to identify the principles that may cause different parties of interest to have greater or lesser power. In doing this, we discuss power from two different angles. On the one hand, we discuss general factors based upon non-idiosyncratic biological features (e.g. information, access to and ability to process food) that are likely to be important to all social Hymenoptera. On the other hand, we discuss idiosyncratic factors that depend upon the biology of a taxon at any hierarchical level. We propose that a better understanding of the diversity of reproductive characteristics of insect societies will come from combining inclusive fitness theory with a wide range of other factors that affect relative power in a conflict situation.}, } @article {pmid14561293, year = {2003}, author = {Gilley, DC}, title = {Absence of nepotism in the harassment of duelling queens by honeybee workers.}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1528}, pages = {2045-2049}, pmid = {14561293}, issn = {0962-8452}, mesh = {Aggression/*physiology ; Animals ; Bees/*genetics/*physiology ; Biological Evolution ; Competitive Behavior/*physiology ; Female ; Microsatellite Repeats ; Population Dynamics ; *Selection, Genetic ; }, abstract = {Nepotism shapes interactions among the members of almost every animal society. However, clear evidence of nepotism within highly cooperative insect societies, such as ant, wasp and honeybee colonies, is rare. Recent empirical findings suggest that nepotism occurs within honeybee colonies where kin-selection theory most strongly predicts its existence: during the lethal queen-queen duels that determine which of several young queens will become the colony's next queen. In this study, I test whether worker bees act nepotistically by hindering duelling queens that are distantly related to themselves. I accomplished this by observing labelled workers harassing duelling queen bees in observation hives and subsequently by determining worker-queen relatedness using DNA microsatellites. I show that the workers that harassed duelling queens were neither more-closely nor more-distantly related to them than were workers selected randomly from the colony. Thus, workers did not behave nepotistically by hindering half-sister queens more than full-sister queens. These results demonstrate that under certain conditions, natural selection limits the evolution of nepotism within animal societies despite strong theoretical predictions for its existence.}, } @article {pmid14561291, year = {2003}, author = {Gemmell, NJ}, title = {Kin selection may influence fostering behaviour in Antarctic fur seals (Arctocephalus gazella).}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1528}, pages = {2033-2037}, pmid = {14561291}, issn = {0962-8452}, mesh = {Animals ; Animals, Suckling/*genetics ; Antarctic Regions ; Atlantic Islands ; Female ; Fur Seals/*genetics/*physiology ; Lactation/physiology ; Maternal Behavior/*physiology ; Microsatellite Repeats ; *Selection, Genetic ; }, abstract = {Fostering confers obvious advantages to the offspring but is seemingly costly to the caregiver. Such behaviour is particularly paradoxical in seals where the energetic investment in milk is very high and has led to the suggestion that this behaviour may have evolved through either kin selection or reciprocity. We used a combination of genetic and behavioural data to investigate whether kin selection plays a role in the fostering behaviour observed in a well-studied population of Antarctic fur seals (Arctocephalus gazella) from Bird Island, South Georgia. Genotypic data from eight highly polymorphic microsatellite markers were used to estimate relatedness among mother-pup pairs, foster mother-pup pairs and the total population. Mean relatedness was found to be significantly higher for foster mother-pup pairs than that observed for the total population, suggesting that kin selection could have a role in the maintenance of fostering behaviour in this species.}, } @article {pmid14557542, year = {2003}, author = {Hartmann, A and Wantia, J and Torres, JA and Heinze, J}, title = {Worker policing without genetic conflicts in a clonal ant.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {100}, number = {22}, pages = {12836-12840}, pmid = {14557542}, issn = {0027-8424}, mesh = {Aggression ; Animals ; Ants/growth & development/*physiology ; Conflict, Psychological ; Female ; Larva ; Parthenogenesis ; Reproduction ; Sexual Behavior, Animal/physiology ; *Social Behavior ; }, abstract = {In group-living animals, mutual policing to suppress reproduction is an important mechanism in the resolution of conflict between selfish group members and the group as a whole. In societies of bees, ants, and wasps, policing against the production of males by other workers is expected when egg laying by workers decreases the average inclusive fitness of individual group members. This may result (i) from the relatedness of workers being lower to worker than to queen-derived males or (ii) from a lowered overall colony efficiency. Whereas good evidence exists for policing behavior caused by genetic conflicts, policing caused by efficiency factors has not been demonstrated. We investigated the regulation of reproduction in the ant Platythyrea punctata, a species in which colonies are clones because workers are capable of producing female offspring by thelytokous parthenogenesis. Reproductive conflicts resulting from differences in genetic relatedness are therefore not expected, but uncontrolled reproduction by all workers could lead to the destruction of sociality. Here we show that worker policing by aggressive attacks against additionally reproducing workers keeps the number of reproducing workers low. Furthermore, through experimental manipulation of the number of brood items per colony, we show that worker policing can enhance group efficiency.}, } @article {pmid12957119, year = {2003}, author = {Tullberg, J}, title = {Rationality and social behavior.}, journal = {Journal of theoretical biology}, volume = {224}, number = {4}, pages = {469-478}, doi = {10.1016/s0022-5193(03)00194-2}, pmid = {12957119}, issn = {0022-5193}, mesh = {Altruism ; Animals ; Behavior, Animal ; Biological Evolution ; Cooperative Behavior ; Ethics ; *Group Processes ; Humans ; Selection, Genetic ; *Social Behavior ; }, abstract = {This article penetrates the relationship between social behavior and rationality. A critical analysis is made of efforts to classify some behaviors as altruistic, as they simultaneously meet criteria of rationality by not truly being self-destructive. Newcomb's paradox is one attempt to create a hybrid behavior that is both irrational and still meets some criterion of rationality. Such dubious rationality is often seen as a source of altruistic behavior. Group selection is a controversial topic. Sober and Wilson (Unto Others--The Evolution and Psychology of Unselfish Behavior, Harvard University Press, Cambridge, MA, 1998) suggest that a very wide concept of group selection might be used to explain altruism. This concept also includes kin selection and reciprocity, which blurs its focus. The latter mechanisms hardly need further arguments to prove their existence. This article suggests that it is group selection in a strict sense that should be investigated to limit semantic neologism and confusion. In evaluation, the effort to muster a mechanism for altruism out of group selection has not been successful. However, this is not the end to group selection, but rather a good reason to investigate more promising possibilities. There is little reason to burden group selection with the instability of altruism caused by altruistic members of a group having lower fitness than egoistic members. Group selection is much more likely to develop in combination with group egoism. A common project is supported by incitement against free riding, where conformist members joined in solidarity achieve a higher fitness than members pursuing more individualistic options. Group egoism is in no conflict with rationality, and the effects of group selection will be supported rather than threatened by individual selection. Empirical evidence indicates a high level of traits such as conformism and out-group antagonism in line with group egoism. These traits are also likely candidates for behavior favored by group selection since they homogenize the group and link the different individuals closer to one another and a similar fate.}, } @article {pmid12919478, year = {2003}, author = {Ortega, J and Maldonado, JE and Wilkinson, GS and Arita, HT and Fleischer, RC}, title = {Male dominance, paternity, and relatedness in the Jamaican fruit-eating bat (Artibeus jamaicensis).}, journal = {Molecular ecology}, volume = {12}, number = {9}, pages = {2409-2415}, doi = {10.1046/j.1365-294x.2003.01924.x}, pmid = {12919478}, issn = {0962-1083}, mesh = {Alleles ; Animals ; Chiroptera/*genetics/*physiology ; Electrophoresis, Polyacrylamide Gel ; Female ; *Genetic Variation ; *Genetics, Population ; Male ; Mexico ; Microsatellite Repeats/genetics ; Reproduction/*genetics ; *Social Dominance ; }, abstract = {We analysed variation at 14 nuclear microsatellite loci to assess the genetic structure, relatedness, and paternity of polygynous Jamaican fruit-eating bats. A total of 84 adults captured in two caves exhibited little genetic differentiation between caves (FST = 0.008). Average relatedness among adult females in 10 harem groups was very low (R = 0.014 +/- 0.011), providing no evidence of harem structure. Dominant and subordinate males shared paternity in large groups, while dominant and satellite males shared paternity in smaller groups. However, our results suggest that male rank influences paternity. Dominant males fathered 69% of 40 offspring, followed by satellite (22%) and subordinate males (9%). Overall adult male bats are not closely related, however, in large harem groups we found that subordinate and dominant males exhibited relatedness values consistent with a father-offspring relationship. Because dominant and subordinate males also sired all the pups in large groups, we propose that their association provides inclusive fitness to them.}, } @article {pmid12888314, year = {2003}, author = {Hill, EM and Grabel, D and McCurren, R}, title = {Impairment in family caregiving: a biological perspective.}, journal = {Medical hypotheses}, volume = {61}, number = {2}, pages = {248-258}, doi = {10.1016/s0306-9877(03)00156-7}, pmid = {12888314}, issn = {0306-9877}, mesh = {Aged ; *Caregivers/psychology ; Child ; Child Abuse/prevention & control/psychology ; Cultural Characteristics ; Decision Making ; Elder Abuse/prevention & control/psychology ; Humans ; Models, Biological ; Risk Factors ; Social Environment ; }, abstract = {This paper focuses on patterns in the care of children and dependent elders, providing a new perspective to understand impairment in family caregiving. One concept from evolutionary theory, kin selection, has promise for providing a broad framework for understanding patterns of family caregiving. We present an application of the evolutionary model to the issue of family care decisions in the face of potential conflicts of interest. Specifically, a mathematical biological model, which was developed to understand self-preservation motivation, is applied to the kin investment decision. Using the evolutionary model, the main predictors of investment would be relatedness, reproductive value, and expected benefit from the care invested. The biological model accounts very simply for decisions between caring for an elder parent or caring for your own child, and for decisions by two daughters (one with a child, one childless) to care for an elder parent. The factors that form the basis of an evolutionary model (relatedness, reproductive value, and benefit from care) have not been widely investigated in family care studies, however, and this absence reveals new directions for future research.}, } @article {pmid12875829, year = {2003}, author = {Mohtashemi, M and Mui, L}, title = {Evolution of indirect reciprocity by social information: the role of trust and reputation in evolution of altruism.}, journal = {Journal of theoretical biology}, volume = {223}, number = {4}, pages = {523-531}, doi = {10.1016/s0022-5193(03)00143-7}, pmid = {12875829}, issn = {0022-5193}, mesh = {*Altruism ; *Biological Evolution ; *Computer Simulation ; Humans ; Interpersonal Relations ; Memory ; *Models, Psychological ; Social Desirability ; Trust ; }, abstract = {The complexity of human's cooperative behavior cannot be fully explained by theories of kin selection and group selection. If reciprocal altruism is to provide an explanation for altruistic behavior, it would have to depart from direct reciprocity, which requires dyads of individuals to interact repeatedly. For indirect reciprocity to rationalize cooperation among genetically unrelated or even culturally dissimilar individuals, information about the reputation of individuals must be assessed and propagated in a population. Here, we propose a new framework for the evolution of indirect reciprocity by social information: information selectively retrieved from and propagated through dynamically evolving networks of friends and acquaintances. We show that for indirect reciprocity to be evolutionarily stable, the differential probability of trusting and helping a reputable individual over a disreputable individual, at a point in time, must exceed the cost-to-benefit ratio of the altruistic act. In other words, the benefit received by the trustworthy must out-weigh the cost of helping the untrustworthy.}, } @article {pmid12867980, year = {2003}, author = {Helms Cahan, S and Keller, L}, title = {Complex hybrid origin of genetic caste determination in harvester ants.}, journal = {Nature}, volume = {424}, number = {6946}, pages = {306-309}, doi = {10.1038/nature01744}, pmid = {12867980}, issn = {1476-4687}, mesh = {Animals ; Ants/classification/*genetics/*physiology ; Crosses, Genetic ; Female ; Gene Frequency ; Genome ; Genotype ; Male ; Models, Genetic ; Phylogeny ; *Social Dominance ; Species Specificity ; }, abstract = {Caste differentiation and division of labour are the hallmarks of insect societies and at the root of their ecological success. Kin selection predicts that caste determination should result from environmentally induced differences in gene expression, a prediction largely supported by empirical data. However, two exceptional cases of genetically determined caste differentiation have recently been found in harvester ants. Here we show that genetic caste determination evolved in these populations after complex hybridization events. We identified four distinct genetic lineages, each consisting of unique blends of the genomes of the parental species, presumably Pogonomyrmex barbatus and P. rugosus. Crosses between lineages H1 and H2 and between J1 and J2 give rise to workers, whereas queens develop from within-lineage matings. Although historical gene flow is evident, genetic exchange among lineages and between lineages and the parental species no longer occurs. This unusual system of caste determination seems to be evolutionarily stable.}, } @article {pmid12840760, year = {2003}, author = {Schaal, B and Coureaud, G and Langlois, D and Giniès, C and Sémon, E and Perrier, G}, title = {Chemical and behavioural characterization of the rabbit mammary pheromone.}, journal = {Nature}, volume = {424}, number = {6944}, pages = {68-72}, doi = {10.1038/nature01739}, pmid = {12840760}, issn = {1476-4687}, mesh = {Animals ; Animals, Newborn/*physiology ; Animals, Suckling/*physiology ; Chromatography, Gas ; Female ; Gases/analysis/chemistry ; Mammary Glands, Animal/*chemistry ; Milk/*chemistry ; Nipples/chemistry ; Odorants/analysis ; Pheromones/analysis/*chemistry/*physiology ; Phylogeny ; Rabbits ; Smell/*physiology ; }, abstract = {Mammals owe part of their evolutionary success to the harmonious exchanges of information, energy and immunity between females and their offspring. This functional reciprocity is vital for the survival and normal development of infants, and for the inclusive fitness of parents. It is best seen in the intense exchanges taking place around the mother's offering of, and the infant's quest for, milk. All mammalian females have evolved behavioural and sensory methods of stimulating and guiding their inexperienced newborns to their mammae, whereas newborns have coevolved means to respond to them efficiently. Among these cues, maternal odours have repeatedly been shown to be involved, but the chemical identity and pheromonal nature of these cues have not been definitively characterized until now. Here we focus on the nature of an odour signal emitted by the female rabbit to which newborn pups respond by attraction and oral grasping, and provide a complete chemical and behavioural description of a pheromone of mammary origin in a mammalian species.}, } @article {pmid12837935, year = {2003}, author = {Boomsma, JJ and Nielsen, J and Sundström, L and Oldham, NJ and Tentschert, J and Petersen, HC and Morgan, ED}, title = {Informational constraints on optimal sex allocation in ants.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {100}, number = {15}, pages = {8799-8804}, pmid = {12837935}, issn = {0027-8424}, mesh = {Animals ; Ants/genetics/growth & development/*physiology ; Female ; Finland ; Genetics, Population ; Hydrocarbons/analysis ; Male ; Odorants ; Selection, Genetic ; Sex Ratio ; Social Behavior ; }, abstract = {Workers of the ant Formica truncorum specialize in rearing females or males depending on the number of fathers of a colony. These split sex ratios increase inclusive fitness, but it has remained unknown how workers assess the number of patrilines in their colonies and to what extent their reproductive decisions are constrained by lack of information. By analysis of the quantitative variation in cuticular hydrocarbon profiles of workers of multiply mated queens, we show that the heritable component of recognition cues is low and that the extent of sex ratio biasing toward males is correlated with patriline differences in hydrocarbon profiles. Workers are thus able to capitalize on colony-level relatedness asymmetry, but their inclusive fitness is constrained by uninformative recognition cues. These results are consistent with the hypothesis that the occasional expression of nepotistic phenotypes favoring full-sisters over half-sisters maintains selection against informative recognition cues. We evaluate how inclusive fitness theory may be used to predict the number and kind of recognition cues in insect societies of a specific relatedness structure.}, } @article {pmid12817149, year = {2003}, author = {Baglione, V and Canestrari, D and Marcos, J and Ekman, J}, title = {Kin selection in cooperative alliances of carrion crows.}, journal = {Science (New York, N.Y.)}, volume = {300}, number = {5627}, pages = {1947-1949}, doi = {10.1126/science.1082429}, pmid = {12817149}, issn = {1095-9203}, mesh = {Animals ; *Behavior, Animal ; Biological Evolution ; *Breeding ; Cooperative Behavior ; Female ; Male ; Microsatellite Repeats ; Reproduction ; *Selection, Genetic ; Sexual Behavior, Animal ; Social Behavior ; Songbirds/genetics/*physiology ; Spain ; Territoriality ; }, abstract = {In most cooperative vertebrates, delayed natal dispersal is the mechanism that leads to the formation of kin societies. Under this condition, the possibility that kin-based cooperative breeding is an unselected consequence of dispersal patterns can never be ruled out because helpers can only help their relatives. Here we show that a population of carrion crows (Corvus corone corone) fully fits the central prediction of kin selection theory that cooperative breeding should arise among relatives. On their territory, resident breeders are aided not only by nonbreeding retained offspring but also by immigrants (mainly males), with whom they share matings. Philopatry cannot account, however, for the high degree of genetic relatedness found between breeders and immigrants of the same sex that cooperate at a nest, indicating that crows actively choose to breed cooperatively with their relatives.}, } @article {pmid12778541, year = {2003}, author = {Frank, SA}, title = {Perspective: repression of competition and the evolution of cooperation.}, journal = {Evolution; international journal of organic evolution}, volume = {57}, number = {4}, pages = {693-705}, doi = {10.1111/j.0014-3820.2003.tb00283.x}, pmid = {12778541}, issn = {0014-3820}, support = {AI24424/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; *Competitive Behavior ; *Cooperative Behavior ; Hymenoptera/physiology ; Meiosis/genetics ; *Models, Genetic ; *Selection, Genetic ; Symbiosis ; }, abstract = {Repression of competition within groups joins kin selection as the second major force in the history of life shaping the evolution of cooperation. When opportunities for competition against neighbors are limited within groups, individuals can increase their own success only by enhancing the efficiency and productivity of their group. Thus, characters that repress competition within groups promote cooperation and enhance group success. Leigh first expressed this idea in the context of fair meiosis, in which each chromosome has an equal chance of transmission via gametes. Randomized success means that each part of the genome can increase its own success only by enhancing the total number of progeny and thus increasing the success of the group. Alexander used this insight about repression of competition in fair meiosis to develop his theories for the evolution of human sociality. Alexander argued that human social structures spread when they repress competition within groups and promote successful group-against-group competition. Buss introduced a new example with his suggestion that metazoan success depended on repression of competition between cellular lineages. Maynard Smith synthesized different lines of thought on repression of competition. In this paper, I develop simple mathematical models to illustrate the main processes by which repression of competition evolves. With the concepts made clear, I then explain the history of the idea. I finish by summarizing many new developments in this subject and the most promising lines for future study.}, } @article {pmid12755887, year = {2003}, author = {Brown, MJ and Schmid-Hempel, R and Schmid-Hempel, P}, title = {Queen-controlled sex ratios and worker reproduction in the bumble bee Bombus hypnorum, as revealed by microsatellites.}, journal = {Molecular ecology}, volume = {12}, number = {6}, pages = {1599-1605}, doi = {10.1046/j.1365-294x.2003.01840.x}, pmid = {12755887}, issn = {0962-1083}, mesh = {Alleles ; Animals ; Bees/*genetics/*physiology ; DNA Primers ; Electrophoresis ; Female ; Finland ; Male ; Microsatellite Repeats/genetics ; Reproduction/physiology ; *Sex Ratio ; Sexual Behavior, Animal/*physiology ; *Social Dominance ; Sweden ; }, abstract = {Social insect colonies provide model systems for the examination of conflicts among parties with different genetic interests. As such, they have provided the best tests of inclusive fitness theory. However, much remains unknown about in which party's favour such conflicts are resolved, partly as a result of the only recent advent of the molecular tools needed to examine the outcome of these conflicts. Two key conflicts in social insect colonies are over control of the reproductive sex ratio and the production of male offspring. Most studies have examined only one of these conflicts but in reality they occur in tandem and may influence each other. Using microsatellite analyses, the outcome of conflict over sex ratios and male production was examined in the bumble bee, Bombus hypnorum. The genotypes were determined for mother queens, their mates and males for each of 10 colonies. In contrast to other reports of mating frequency in this species, all of the queens were singly mated. The population sex ratio was consistent with queen control, suggesting that queens are winning this conflict. In contrast, workers produced over 20% of all males in queen-right colonies, suggesting that they are more effective in competing over male-production. Combining these results with previous work, it is suggested that worker reproduction is a labile trait that may well impose only small costs on queen fitness.}, } @article {pmid12741187, year = {2003}, author = {Greeff, JM and van Noort, S and Rasplus, JY and Kjellberg, F}, title = {Dispersal and fighting in male pollinating fig wasps.}, journal = {Comptes rendus biologies}, volume = {326}, number = {1}, pages = {121-130}, doi = {10.1016/s1631-0691(03)00010-6}, pmid = {12741187}, issn = {1631-0691}, mesh = {*Agonistic Behavior ; Animals ; Biological Evolution ; Female ; Ficus/parasitology ; Male ; Phylogeny ; Pollen ; Sex Ratio ; *Sexual Behavior, Animal ; Siblings ; Species Specificity ; *Territoriality ; Wasps/anatomy & histology/*physiology ; }, abstract = {For more than two decades, it has been the dogma that the males of pollinating fig wasps do not fight and that they only mate in their native fig. Their extreme degree of local mating leads to highly female biased sex ratios that should eliminate the benefits of fighting and dispersal by males. Furthermore, males sharing a fig are often brothers, and fighting may be barred by kin selection. Therefore, theory supported the presumed absence of fighting and dispersal in pollinating fig wasp males. However, we report here that in pollinating fig wasps, fighting between brothers evolved at least four and possibly six time, and dispersal by males at least twice. This finding supports the idea that competition between relatives can cancel the ameliorating effects of relatedness. The explanation to this evolutionary puzzle, as well as the consequences of male dispersal and fighting, opens the doors to exciting new research.}, } @article {pmid12737659, year = {2003}, author = {Bono, JM and Herbers, JM}, title = {Proximate and ultimate control of sex ratios in Myrmica brevispinosa colonies.}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1517}, pages = {811-817}, pmid = {12737659}, issn = {0962-8452}, mesh = {Animals ; Ants/*physiology ; Environment ; Female ; Food ; Male ; Population Density ; *Sex Ratio ; }, abstract = {The literature on sex ratio evolution in ant colonies is dominated by inclusive fitness arguments. In general, genetic theory makes good predictions about sexual investment in ant populations, but understanding colony-level variance in sex investment ratios has proven more difficult. Recently, however, more studies have addressed ecological factors that influence colony-level sex investment ratios. Food availability, in particular, has been manipulated because larval nutrition influences female caste determination, thus implying that resource availability should be of critical importance for colony sex investment ratios. However, results from food supplementation experiments are equivocal, and it is clear that ant colony response to food supplementation is dependent on the ecological background of the population. We presented field colonies of the ant Myrmica brevispinosa with two food types (proteins and carbohydrates), and assessed their relative impact on colony-level sex investment ratios. We show that colonies receiving carbohydrate enhancement invested in more female sexuals and produced more female-biased sex allocation ratios than protein-fed or control colonies. Thus, our study is the first, to our knowledge, to demonstrate that sex ratios in social insect colonies might be sensitive to resource quality. Male investment was not influenced by food treatment, but was positively correlated with colony size. Therefore, the shift in sex ratios in our study must have been mediated through nutritional influences on female caste determination rather than male brood elimination. We also used our data to evaluate evidence for sex ratio compensation by queenright colonies in response to male production by workers from orphaned colonies.}, } @article {pmid12732479, year = {2003}, author = {Marshall, JA and Rowe, JE}, title = {Kin selection may inhibit the evolution of reciprocation.}, journal = {Journal of theoretical biology}, volume = {222}, number = {3}, pages = {331-335}, doi = {10.1016/s0022-5193(03)00039-0}, pmid = {12732479}, issn = {0022-5193}, mesh = {Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Game Theory ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Kin selection and reciprocal cooperation provide two candidate explanations for the evolution of cooperation. Models of the evolution of cooperation have typically focussed on one or the other mechanism, despite claims that kin selection could pave the way for the evolution of reciprocal cooperation. We describe a computer simulation model that explicitly supports both kin selection and reciprocal cooperation. The model simulates a viscous population of discrete individuals with social interaction taking the form of the Prisoner's Dilemma and selection acting on performance in these interactions. We recount how the analytical and empirical study of this model led to the conclusion that kin selection may actually inhibit the evolution of effective strategies for establishing reciprocal cooperation.}, } @article {pmid12704711, year = {2003}, author = {Crognier, E}, title = {Reproductive success: which meaning?.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {15}, number = {3}, pages = {352-360}, doi = {10.1002/ajhb.10153}, pmid = {12704711}, issn = {1042-0533}, mesh = {Family Characteristics ; Female ; Fertility ; Humans ; Male ; Models, Biological ; Reproduction/*physiology ; Sexual Behavior ; }, abstract = {The theory of kin selection (the part played by behavior in the changes of mean inclusive fitness) induced many human sociobiologists to think that since behavior was involved in the increase in fitness, this last entity could apply to the individual. Approximated by the individual's lifetime reproductive success, this measure became the keyword of studies linking social and cultural behavior to biological adaptive processes. To be commonly applicable to human populations, it had to be simplified to represent the number of offspring reaching sexual maturity and most existing studies are based on this definition. The current trend, however, seems to consider that, like inbreeding, reproductive success takes its signification in the depth of successive generations. These diverse measures were tested in two traditional populations, Berber and Aymara, and show that finding a satisfactory evaluation of reproductive success is a problem that is still far from a solution.}, } @article {pmid12699220, year = {2003}, author = {Härdling, R and Kokko, H and Arnold, KE}, title = {Dynamics of the caring family.}, journal = {The American naturalist}, volume = {161}, number = {3}, pages = {395-412}, doi = {10.1086/367587}, pmid = {12699220}, issn = {0003-0147}, mesh = {Animals ; Biological Evolution ; Conflict, Psychological ; *Cooperative Behavior ; Energy Metabolism ; *Feeding Behavior ; Heredity ; Models, Biological ; Nesting Behavior ; *Reproduction ; }, abstract = {When several individuals simultaneously provide for offspring, as in families, the effort of any one individual will depend on the efforts of the other family members. This conflict of interest among family members is made more complicated by their relatedness because relatives share genetic interest to some degree. The conflict resolution will also be influenced by the differences in reproductive value between breeders and helpers. Here, we calculate evolutionarily stable provisioning efforts in families with up to two helpers. We explicitly consider that the behavioral choices are made in a life-history context, and we also consider how group sizes change dynamically; this affects, for example, average relatedness among group members. We assume two different scenarios: intact families in which the breeder is 100% monogamous and stepfamilies in which the breeder shifts mate between breeding events. The average relatedness among family members is allowed to evolve in concert with changes in provisioning effort. Our model shows that an individual's provisioning effort is not easy to predict from either its relatedness to the offspring or its reproductive value. Instead, it is necessary to consider the inclusive fitness effect of provisioning, which is determined by a combination of relatedness, reproductive value, and the reproductive value of the offspring.}, } @article {pmid12691176, year = {2002}, author = {Illius, AW and Tolkamp, BJ and Yearsley, J}, title = {The evolution of the control of food intake.}, journal = {The Proceedings of the Nutrition Society}, volume = {61}, number = {4}, pages = {465-472}, doi = {10.1079/pns2002179}, pmid = {12691176}, issn = {0029-6651}, mesh = {Animals ; Behavior Control ; *Biological Evolution ; Eating/*physiology ; Environment ; Genotype ; *Homeostasis ; Humans ; Physical Fitness ; }, abstract = {The ultimate goal of an organism is to maximise its inclusive fitness, and an important sub-goal must be the optimisation of the lifetime pattern of food intake, in order to meet the nutrient demands of survival, growth and reproduction. The conventional assumption that fitness is maximised by maximising daily food intake, subject to physical and physiological constraints, has been challenged recently. Instead, it can be argued that fitness is maximised by balancing benefits and costs over the organism's lifetime. The fitness benefits of food intake are a function of its contribution to survival, growth (including necessary body reserves) and reproduction. Against these benefits must be set costs. These costs include not only extrinsic foraging costs and risks, such as those due to predation, but also intrinsic costs associated with food intake, such as obesity and oxidative metabolism that may reduce vitality and lifespan. We argue that the aggregate of benefits and costs form the fitness function of food intake and present examples of such an approach to predicting optimal food intake.}, } @article {pmid12675828, year = {2003}, author = {Coltman, DW and Pilkington, JG and Pemberton, JM}, title = {Fine-scale genetic structure in a free-living ungulate population.}, journal = {Molecular ecology}, volume = {12}, number = {3}, pages = {733-742}, doi = {10.1046/j.1365-294x.2003.01762.x}, pmid = {12675828}, issn = {0962-1083}, mesh = {Adenosine Deaminase/chemistry/genetics ; Alleles ; Animals ; Aspartate Aminotransferase, Mitochondrial/chemistry/genetics ; Atlantic Islands ; *Behavior, Animal ; Censuses ; DNA/chemistry/genetics ; Female ; *Genetics, Population ; Hemoglobins/chemistry/genetics ; Inbreeding ; Isocitrate Dehydrogenase/chemistry/genetics ; Male ; Microsatellite Repeats/genetics ; Population Dynamics ; Scotland ; Sex Factors ; Sheep/*genetics ; Social Behavior ; Transferrin/chemistry/genetics ; }, abstract = {The fine-scale genetic structure of wild animal populations has rarely been analysed, yet is potentially important as a confounding factor in quantitative genetic and allelic association studies, as well as having implications for population dynamics, inbreeding and kin selection. In this study, we examined the extent to which the three spatial subunits, or hefts, of the Village Bay population of Soay sheep (Ovis aries) on St Kilda, Scotland, are genetically structured using data from 20 microsatellite and protein loci. Allele frequencies differed significantly among three hefts in all the study years we considered (1987-2000 inclusive). Small but significantly positive F(ST) and negative F(IS) values were observed in most years, indicating that the hefts are genetically differentiated, and that within each heft there is more observed heterozygosity than would be expected if each were an isolated breeding population. Males showed less fidelity to their natal heft, and as a consequence higher levels of relatedness within hefts were observed among females than among males. There was a significant negative relationship between geographical proximity and relatedness in pairwise comparisons involving females, and on average pairs of females located within 50 m of each other were related at the equivalent level of second cousins. Structure is therefore largely driven by incomplete postnatal dispersal by females. Mating appears to be random with respect to the spatial-genetic substructure of the hefts, and therefore genetic structure does not contribute to the overall rate of inbreeding in the population. However, genetic substructure can lead to allelic associations and generate environmental effects within lineages that have the potential to confound heritability analyses and allelic association studies.}, } @article {pmid12650467, year = {2003}, author = {Loeb, ML}, title = {Evolution of egg dumping in a subsocial insect.}, journal = {The American naturalist}, volume = {161}, number = {1}, pages = {129-142}, doi = {10.1086/344918}, pmid = {12650467}, issn = {0003-0147}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Cooperative Behavior ; Female ; Insecta/genetics/*parasitology/*physiology ; Litter Size ; Ovum/*physiology ; Reproduction/*physiology ; Selection, Genetic ; }, abstract = {Egg dumping, or abandonment of eggs and young to the care of other conspecifics, frees individuals from costs of maternal care while potentially imposing energetic and ecological costs on egg recipients. It is not clear, however, that egg dumping necessarily represents selfish manipulation of egg recipients, and in some ecological contexts, recipients may benefit from enlarged broods. Thus, egg dumping may either be mutually beneficial for dumpers and recipients or entail costs for dumpers that are compensated by other means, such as improving reproduction of genetically related egg recipients. Here I use field experiments to test the relative importance of manipulation (i.e., "parasitism"), mutualism, and kin selection in the evolution of egg dumping in the tingid lace bug Gargaphia solani. In support of mutualism and kin selection, I found that reproduction of egg recipient G. solani benefits from brood enlargement, most likely because eggs and gregarious nymphs find safety in greater numbers. But contrary to both parasitism and mutualism, egg dumper reproduction was not improved by offspring abandonment. Indeed, dumpers laid smaller clutches than recipients, and dumpers did not convert a survival advantage into greater future reproduction. Genetic analyses of a natural G. solani population revealed, however, that dumpers are related to their egg recipients. Moreover, Hamilton's rule showed that egg-dumping G. solani earn sufficient indirect genetic benefits for kin selection to favor the behavior. Thus, egg dumping in some species may be kin-selected cooperation rather than parasitism or mutualism.}, } @article {pmid12641904, year = {2003}, author = {Krützen, M and Sherwin, WB and Connor, RC and Barré, LM and Van de Casteele, T and Mann, J and Brooks, R}, title = {Contrasting relatedness patterns in bottlenose dolphins (Tursiops sp.) with different alliance strategies.}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1514}, pages = {497-502}, pmid = {12641904}, issn = {0962-8452}, mesh = {Animals ; Biological Evolution ; *Cooperative Behavior ; Dolphins/*genetics/*physiology ; Female ; Male ; *Sexual Behavior, Animal ; }, abstract = {Male bottlenose dolphins (Tursiops sp.) in Shark Bay have one of the most complex male societies outside humans. Two broad mating strategies have been identified in males. In the first strategy, there are two types of alliances: stable 'first-order' pairs and trios that herd individual females in reproductive condition, and 'second-order' teams of two first-order alliances (five or six individuals) that join forces against rivals in contests for females. In the alternative strategy, a 'super-alliance' of ca. 14 individuals, males form pairs or trios to herd females, but in contrast to the stable alliances, these pairs and trios are highly labile. Here, we show that males in stable first-order alliances and the derived second-order alliances are often strongly related, so that they may gain inclusive fitness benefits from alliance membership. By contrast, members of the super-alliance are no more closely related than expected by chance. Further, the strength of the association of alliance partners within the super-alliance, as measured by an index of joint participation in consorting a female, was not correlated with their genetic relatedness. Thus, within one population and one sex, it appears that there may be simultaneous operation of more than one mode of group formation.}, } @article {pmid12640144, year = {2003}, author = {Wolf, JB}, title = {Genetic architecture and evolutionary constraint when the environment contains genes.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {100}, number = {8}, pages = {4655-4660}, pmid = {12640144}, issn = {0027-8424}, mesh = {Animals ; *Biological Evolution ; Body Constitution/genetics ; Drosophila melanogaster/*genetics/growth & development/physiology ; Environment ; Female ; Male ; *Models, Genetic ; Phenotype ; Social Environment ; }, abstract = {The environment provided by conspecifics is often the most important component of the environment experienced by individuals, frequently having profound effects on fitness and trait expression. Although these social effects on fitness and trait expression may appear to be purely environmental, they differ from other sorts of environmental influences, because they can have a genetic basis and thus can contribute to evolution. Theory has shown that these effects modify the definition of genetic architecture by making the phenotype the property of the genotypes of multiple individuals and alter evolutionary dynamics by introducing additional heritable components contributing to trait evolution. These effects suggest that genetic and evolutionary analyses of traits influenced by social environments must incorporate the genetic components of variation contributed by these environments. However, empirical studies incorporating these effects are generally lacking. In this paper, I quantify the contribution of genetically based environmental effects arising from social interactions during group rearing to the quantitative genetics of body size in Drosophila melanogaster. The results demonstrate that the genetic architecture of body size contains an important component of variation contributed by the social environment, which is hidden to ordinary genetic analyses and opposes the direct effects of genes on body-size development within a population. Using a model of trait evolution, I show that these effects significantly alter evolutionary predictions by providing hidden constraints on phenotypic evolution. The importance of relatedness of interactants and the potential impact of kin selection on the evolution of body size are also examined.}, } @article {pmid12625087, year = {2002}, author = {Preston, SD and de Waal, FB}, title = {Empathy: Its ultimate and proximate bases.}, journal = {The Behavioral and brain sciences}, volume = {25}, number = {1}, pages = {1-20; discussion 20-71}, doi = {10.1017/s0140525x02000018}, pmid = {12625087}, issn = {0140-525X}, mesh = {Adult ; Animals ; Biological Evolution ; Child ; Emotions/physiology ; *Empathy ; Haplorhini ; Helping Behavior ; Humans ; Mental Disorders/physiopathology/psychology ; Morals ; Personality Development ; Phylogeny ; Prefrontal Cortex/physiopathology ; Socialization ; }, abstract = {There is disagreement in the literature about the exact nature of the phenomenon of empathy. There are emotional, cognitive, and conditioning views, applying in varying degrees across species. An adequate description of the ultimate and proximate mechanism can integrate these views. Proximately, the perception of an object's state activates the subject's corresponding representations, which in turn activate somatic and autonomic responses. This mechanism supports basic behaviors (e.g., alarm, social facilitation, vicariousness of emotions, mother-infant responsiveness, and the modeling of competitors and predators) that are crucial for the reproductive success of animals living in groups. The Perception-Action Model (PAM), together with an understanding of how representations change with experience, can explain the major empirical effects in the literature (similarity, familiarity, past experience, explicit teaching, and salience). It can also predict a variety of empathy disorders. The interaction between the PAM and prefrontal functioning can also explain different levels of empathy across species and age groups. This view can advance our evolutionary understanding of empathy beyond inclusive fitness and reciprocal altruism and can explain different levels of empathy across individuals, species, stages of development, and situations.}, } @article {pmid12614581, year = {2003}, author = {Oli, MK}, title = {Hamilton goes empirical: estimation of inclusive fitness from life-history data.}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1512}, pages = {307-311}, pmid = {12614581}, issn = {0962-8452}, mesh = {Altruism ; Animals ; *Biological Evolution ; *Models, Genetic ; Population Dynamics ; Reproduction/genetics ; *Selection, Genetic ; Sociobiology ; }, abstract = {Hamilton's theory of kin selection is one of the most important advances in evolutionary biology since Darwin. Central to the kin-selection theory is the concept of inclusive fitness. However, despite the importance of inclusive fitness in evolutionary theory, empirical estimation of inclusive fitness has remained an elusive task. Using the concept of individual fitness, I present a method for estimating inclusive fitness and its components for diploid organisms with age-structured life histories. The method presented here: (i) allows empirical estimation of inclusive fitness from life-history data; (ii) simultaneously considers all components of fitness, including timing and magnitude of reproduction; (iii) is consistent with Hamilton's definition of inclusive fitness; and (iv) adequately addresses shortcomings of existing methods of estimating inclusive fitness. I also demonstrate the application of this new method for testing Hamilton's rule.}, } @article {pmid12596763, year = {2003}, author = {Tarpy, DR}, title = {Genetic diversity within honeybee colonies prevents severe infections and promotes colony growth.}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1510}, pages = {99-103}, pmid = {12596763}, issn = {0962-8452}, mesh = {Animals ; Bees/*genetics/microbiology/*physiology ; Female ; *Genetic Predisposition to Disease ; *Genetic Variation ; Male ; Mycoses/*genetics ; Population Growth ; Sexual Behavior, Animal ; }, abstract = {Multiple mating by social insect queens increases the genetic diversity among colony members, thereby reducing intracolony relatedness and lowering the potential inclusive fitness gains of altruistic workers. Increased genetic diversity may be adaptive, however, by reducing the prevalence of disease within a nest. Honeybees, whose queens have the highest levels of multiple mating among social insects, were investigated to determine whether genetic variation helps to prevent chronic infections. I instrumentally inseminated honeybee queens with semen that was either genetically similar (from one male) or genetically diverse (from multiple males), and then inoculated their colonies with spores of Ascosphaera apis, a fungal pathogen that kills developing brood. I show that genetically diverse colonies had a lower variance in disease prevalence than genetically similar colonies, which suggests that genetic diversity may benefit colonies by preventing severe infections.}, } @article {pmid12590769, year = {2003}, author = {West, SA and Buckling, A}, title = {Cooperation, virulence and siderophore production in bacterial parasites.}, journal = {Proceedings. Biological sciences}, volume = {270}, number = {1510}, pages = {37-44}, pmid = {12590769}, issn = {0962-8452}, mesh = {Animals ; Bacteria/*metabolism/*pathogenicity ; Bacterial Infections/microbiology ; Biofilms ; Host-Parasite Interactions ; Models, Biological ; Sex Ratio ; Siderophores/*biosynthesis ; Virulence ; }, abstract = {Kin selection theory predicts that the damage to a host resulting from parasite infection (parasite virulence) will be negatively correlated to the relatedness between parasites within the host. This occurs because a lower relatedness leads to greater competition for host resources, which favours rapid growth to achieve greater relative success within the host, and that higher parasite growth rate leads to higher virulence. We show that a biological feature of bacterial infections can lead to the opposite prediction: a positive correlation between relatedness and virulence. This occurs because a high relatedness can favour greater (cooperative) production of molecules that scavenge iron (siderophores), which results in higher growth rates and virulence. More generally, the same underlying idea can predict a positive relationship between relatedness and virulence in any case where parasites can cooperate to increase their growth rate; other examples include immune suppression and the production of biofilms to aid colonization.}, } @article {pmid12583576, year = {2002}, author = {Cherry, JL}, title = {Deleterious mutation and the evolution of eusociality.}, journal = {Evolution; international journal of organic evolution}, volume = {56}, number = {12}, pages = {2359-2367}, doi = {10.1111/j.0014-3820.2002.tb00161.x}, pmid = {12583576}, issn = {0014-3820}, support = {T32HG000042/HG/NHGRI NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Female ; Genetic Load ; Genetics, Population ; Inbreeding ; Male ; Mathematics ; Models, Genetic ; *Mutation ; Phenotype ; Reproduction ; *Social Behavior ; }, abstract = {Certain arguments concerning the evolution of eusociality form a classic example of the application of the principles of kin selection. These arguments center on the different degrees of relatedness of potential beneficiaries of an individual's efforts, for example a female's higher relatedness to her sisters than to her daughters in a haplodiploid system. This type of reasoning is insufficicnt to account for the evolution and maintainence of sexual reproduction, because parthenogenic females produce offspring that are more closely related to them than are offspring produced sexually. Among the forces invoked to explain sexual reproduction is deleterious mutation. This factor can be shown to favor eusociality as well, because siblings produced by helping carry fewer deleterious alleles on average than would offspring. The strength of this effect depends on the genomewide deleterious mutation rate, U, and on the selection coefficient, s, associated with deleterious alleles. For small s, the effect depends approximately on the product Us. This phenomenon illustrates that an assumption implicit in some analyses-that the relatedness of an individual to an actor is all that matters to its value to that actor-can fail for the evolution of eusociality as it does for the evolution of sex.}, } @article {pmid12579619, year = {2003}, author = {Brüne, M}, title = {Erotomanic stalking in evolutionary perspective.}, journal = {Behavioral sciences & the law}, volume = {21}, number = {1}, pages = {83-88}, doi = {10.1002/bsl.518}, pmid = {12579619}, issn = {0735-3936}, mesh = {Delusions/*psychology ; Erotica/*psychology ; Female ; Humans ; Male ; Sexual Behavior/psychology ; *Sexual Harassment ; }, abstract = {Erotomania, the delusion of being loved by another person, comprises marked sex differences concerning prevalence rates and behavior. Whereas traditional psychiatry has considered erotomania to be almost entirely restricted to women, recent studies have revealed that criminal offenses associated with the condition occur much more frequently in men. The main hypothesis of this article is that these findings may be explained in terms of evolutionary theory. Erotomania, accordingly, may be viewed as a pathological variant of a specific sexual strategy that evolved under selection pressures of the human environment of evolutionary adaptedness. The overt behavior is related to the pursuit of long-term mating, its potentially beneficial effect on inclusive fitness of the individual, and disparate strategies of the sexes to ensure sexual fidelity of the potential partner. Therefore, the evolutionary approach provides a plausible explanation as to why forensically relevant erotomania prevails in men. The pathological process of delusional misinterpretation of perceived signals from the social environment itself may result from poor reality testing due to a failure of social meta-cognition. The evolutionary perspective may provide additional insights into the nature of sex-specific behaviors and may improve our understanding of forensically relevant behaviors.}, } @article {pmid12573063, year = {2002}, author = {Gibson, RM and Aspbury, AS and McDaniel, LL}, title = {Active formation of mixed-species grouse leks: a role for predation in lek evolution?.}, journal = {Proceedings. Biological sciences}, volume = {269}, number = {1509}, pages = {2503-2507}, pmid = {12573063}, issn = {0962-8452}, mesh = {Animals ; Biological Evolution ; Birds/*classification/*physiology ; Female ; Male ; Predatory Behavior ; *Sexual Behavior, Animal ; }, abstract = {Behavioural ecologists have interpreted avian leks as products of sexual selection, in which males display socially to increase their opportunities to mate. However, without invoking reproductive queuing or kin selection, this paradigm does not necessarily explain why many males that fail to mate participate in leks. An alternative solution, that males also aggregate to reduce predation, has previously lacked compelling support. We show that mixed-species leks, comprising two congeneric grouse, form when single males or small groups of one species, the greater prairie chicken Tympanuchus cupido, join leks of another, the sharp-tailed grouse T. phasianellus. We documented the process by observing lek dynamics and comparing group sizes between mixed- and single-species leks. Joining implies that prairie chickens benefit from displaying with sharp-tailed grouse. The numbers of females of each species attending a lek increased with the number of conspecific, but not heterospecific, males. This suggests that the joining of heterospecifics is unlikely to increase mating opportunities, and leaves lowered predation risk as the most likely benefit of associating with heterospecifics. Active formation of mixed-species leks therefore suggests that predation may be sufficient to drive lek formation. The benefits of participation in mixed leks may be asymmetrical because prairie chickens display more and are less vigilant than sharp-tailed grouse.}, } @article {pmid12525936, year = {2003}, author = {Lessard, S and Rocheleau, G}, title = {Change in frequency of a rare mutant allele: a general formula and applications to partial inbreeding models.}, journal = {Journal of mathematical biology}, volume = {46}, number = {1}, pages = {71-94}, doi = {10.1007/s002850200158}, pmid = {12525936}, issn = {0303-6812}, mesh = {*Alleles ; Gene Frequency/*genetics ; *Inbreeding ; *Models, Genetic ; Mutation/*genetics ; Selection, Genetic ; }, abstract = {We deduce and prove a general formula to approximate the change in frequency of a mutant allele under weak selection, when this allele is introduced in small frequency into a population which was previously at a fixation state. We apply the formula to autosomal genes in partial selfing models and to autosomal as well as sex-linked genes in partial sib mating models. It is shown that the fate of a rare mutant allele depends not only on the selection parameters, the inbreeding coefficient and the reproductive values of the sexes in sex-differentiated populations, but also on coefficients of relatedness between mates. This is interpreted as a kin selection effect caused by inbreeding per se.}, } @article {pmid12498698, year = {2002}, author = {Queller, DC and Strassmann, JE}, title = {Kin selection.}, journal = {Current biology : CB}, volume = {12}, number = {24}, pages = {R832}, doi = {10.1016/s0960-9822(02)01344-1}, pmid = {12498698}, issn = {0960-9822}, mesh = {Animals ; Behavior, Animal/*physiology ; Breeding ; *Family ; Hymenoptera/physiology ; *Selection, Genetic ; Sex Ratio ; Sexual Behavior, Animal ; *Social Behavior ; }, } @article {pmid12496736, year = {2002}, author = {van der Dennen, JM}, title = {(Evolutionary) Theories of warfare in preindustrial (foraging) societies.}, journal = {Neuro endocrinology letters}, volume = {23 Suppl 4}, number = {}, pages = {55-65}, pmid = {12496736}, issn = {0172-780X}, mesh = {*Biological Evolution ; Cultural Evolution ; *Ethnology ; Humans ; Selection, Genetic ; Sex Characteristics ; Social Behavior ; *Warfare ; }, abstract = {I present an inventory of theories of war causation (and on the origin of war) in preindustrial (traditional, foraging, 'primitive', hunter-gatherer, band- and tribe-level) societies, with emphasis on the roles of natural selection, sexual selection and kin selection. Also the school of sociocultural evolution is briefly discussed.}, } @article {pmid12487360, year = {2002}, author = {Richardson, DS and Burke, T and Komdeur, J}, title = {Direct benefits and the evolution of female-biased cooperative breeding in Seychelles warblers.}, journal = {Evolution; international journal of organic evolution}, volume = {56}, number = {11}, pages = {2313-2321}, doi = {10.1111/j.0014-3820.2002.tb00154.x}, pmid = {12487360}, issn = {0014-3820}, mesh = {Animals ; *Biological Evolution ; Cooperative Behavior ; Female ; Genotype ; Male ; Microsatellite Repeats ; Sexual Behavior, Animal/*physiology ; Songbirds/genetics/*physiology ; }, abstract = {Inclusive fitness benefits have been suggested to be a major selective force behind the evolution of cooperative breeding. We investigated the fitness benefits selecting for cooperative breeding in the Seychelles warbler, Acrocephalus sechellensis. A microsatellite-based genotyping method was used to determine the relatedness of subordinates to group offspring in an isolated population of Seychelles warblers. The indirect and direct breeding benefits accruing to individual subordinates were then calculated for every successful breeding event over a three-year period. We show that female subordinates frequently gained parentage and that this, combined with high levels of extragroup paternity, resulted in low levels of relatedness between subordinates and nondescendent offspring within a territory. Direct breeding benefits were found to be significantly higher than indirect kin benefits for both female and male subordinates. As predicted, female subordinates gained significantly more direct breeding opportunities and therefore higher inclusive fitness benefits by being a subordinate within a group than did males. This may explain why most subordinates in the Seychelles warbler are female.}, } @article {pmid12381790, year = {2002}, author = {Avilés, L}, title = {Solving the freeloaders paradox: Genetic associations and frequency-dependent selection in the evolution of cooperation among nonrelatives.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {99}, number = {22}, pages = {14268-14273}, pmid = {12381790}, issn = {0027-8424}, mesh = {*Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Models, Biological ; Models, Statistical ; *Selection, Genetic ; }, abstract = {One of the enduring problems in the study of social evolution has been to understand how cooperation can be maintained in the presence of freeloaders, individuals that take advantage of the more cooperative members of groups they are eager to join. The freeloader problem has been particularly troublesome when groups consist of nonrelatives, and no inclusive fitness benefits accrue to individuals that contribute more heavily to communal activities. These theoretical difficulties, however, are not mirrored by the numerous examples of cooperative or even altruistic behaviors exhibited by groups of nonrelatives in nature (e.g., many human groups, communally nesting bees, multiple queen-founding ants, cellular slime molds, and social bacteria). Using a model in which cooperation and grouping tendencies are modeled as coevolving dynamical variables, I show that the freeloader problem can be addressed when group-size effects on fitness are considered explicitly. I show that freeloaders, whose presence is reflected in the development of linkage disequilibrium between grouping and cooperation, increase in frequency when rare, but are selected against when common due to the reduced productivity of the groups they overburden with their presence. Freeloader frequencies thus periodically rise and fall around an equilibrium shown here to be dynamic. These results highlight the importance of group-level effects in the origin and maintenance of sociality, illustrate the dynamic nature of equilibria when multiple levels of selection are involved, and provide a solution to the freeloaders paradox.}, } @article {pmid12350262, year = {2002}, author = {Kappeler, PM and Wimmer, B and Zinner, D and Tautz, D}, title = {The hidden matrilineal structure of a solitary lemur: implications for primate social evolution.}, journal = {Proceedings. Biological sciences}, volume = {269}, number = {1502}, pages = {1755-1763}, pmid = {12350262}, issn = {0962-8452}, mesh = {Animals ; Biological Evolution ; Cheirogaleidae/genetics/*psychology ; DNA, Mitochondrial/genetics ; Female ; Haplotypes ; Male ; Phylogeny ; Sexual Behavior, Animal ; Social Behavior ; }, abstract = {Kin selection affects many aspects of social behaviour, especially in gregarious animals in which relatives are permanently associated. In most group-living primates with complex social behaviour, females are philopatric and organized into matrilines. Models of primate social evolution assume that females in solitary primates are also organized into matrilines. We examined the genetic structure and the mating system of a population of Coquerel's dwarf lemur (Mirza coquereli), a solitary primate from Madagascar, to test this assumption. Our genetic and behavioural analyses revealed that this population of solitary individuals is indeed structured into matrilines, even though this pattern was not predicted by behavioural data. Specifically, females sharing a mitochondrial DNA haplotype were significantly clustered in space and the average genetic and geographical distances among them were negatively correlated. Not all females were philopatric, but there is no evidence for the successful settlement of dispersing females. Although not all adult males dispersed from their natal range, they were not significantly clustered in space and all of them roamed widely in search of oestrous females. As a result, paternity was widely spread among males and mixed paternities existed, indicating that scramble competition polygyny is the mating system of this species. Our data therefore revealed facultative dispersal in both sexes with a strong bias towards female philopatry in this primitive primate. We further conclude that complex kinship structures also exist in non-gregarious species, where their consequences for social behaviour are not obvious.}, } @article {pmid12237403, year = {2002}, author = {Stockley, P and Parker, GA}, title = {Life history consequences of mammal sibling rivalry.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {99}, number = {20}, pages = {12932-12937}, pmid = {12237403}, issn = {0027-8424}, mesh = {*Animal Nutritional Physiological Phenomena ; Animals ; Animals, Suckling ; *Biological Evolution ; Embryo, Mammalian/physiology ; *Family Health ; Female ; Fetus/physiology ; *Lactation ; *Mammals ; Models, Theoretical ; }, abstract = {Mammal life history traits relating to growth and reproduction are extremely diverse. Sibling rivalry may contribute to selection pressures influencing this diversity, because individuals that are relatively large at birth typically have an advantage in competition for milk. However, selection for increased growth rate is likely to be constrained by kin selection and physiological costs. Here, we present and test a model examining the ESS (evolutionarily stable strategy) balance between these constraints and advantages associated with increased prenatal growth in mammal sibling rivalry. Predictions of the model are supported by results of comparative analyses for the Carnivora and Insectivora, which demonstrate an increase in prenatal growth rate with increasing intensity of postnatal scramble competition, and a decrease in postnatal growth rate relative to size at birth. Because increased prenatal growth rates are predicted to select for reduced gestation length under certain conditions, our study also indicates that sibling rivalry may contribute to selection pressures influencing variation in altriciality and precociality among mammals.}, } @article {pmid12233773, year = {2000}, author = {Brown, WD and Keller, L}, title = {Colony sex ratios vary with queen number but not relatedness asymmetry in the ant Formica exsecta.}, journal = {Proceedings. Biological sciences}, volume = {267}, number = {1454}, pages = {1751-1757}, pmid = {12233773}, issn = {0962-8452}, mesh = {Animals ; Ants/*genetics/*physiology ; Female ; Male ; Reproduction ; Sex Ratio ; Social Behavior ; }, abstract = {Split-sex-ratio theory assumes that conflict over whether to produce predominately males or female reproductives (gynes) is won by the workers in haplodiploid insect societies and the outcome is determined by colony kin structure. Tests of the theory have the potential to provide support for kin-selection theory and evidence of social conflict. We use natural variation in kinship among polygynous (multiple-queen) colonies of the ant Formica exsecta to study the associations between sex ratios and the relatedness of workers to female versus male brood (relatedness asymmetry). The population showed split sex ratios with about 89% of the colonies producing only males, resulting in an extremely male-biased investment ratio in the population. We make two important points with our data. First, we show that queen number may affect sex ratio independently of relatedness asymmetry. Colonies producing only males had greater genetic effective queen number but did not have greater relatedness asymmetry from the perspective of the adult workers that rear the brood. This lack of a difference in relatedness asymmetry between colonies producing females and those producing only males was associated with a generally low relatedness between workers and brood. Second, studies that suggest support for the relatedness-asymmetry hypothesis based on indirect measures of relatedness asymmetry (e.g. queen number estimated from relatedness data taken from the brood only) should be considered with caution. We propose a new hypothesis that explains split sex ratios in polygynous social insects based on the value of producing replacement queens.}, } @article {pmid12209574, year = {2002}, author = {Jamison, CS and Cornell, LL and Jamison, PL and Nakazato, H}, title = {Are all grandmothers equal? A review and a preliminary test of the "grandmother hypothesis" in Tokugawa Japan.}, journal = {American journal of physical anthropology}, volume = {119}, number = {1}, pages = {67-76}, doi = {10.1002/ajpa.10070}, pmid = {12209574}, issn = {0002-9483}, mesh = {*Adaptation, Physiological ; Censuses ; Child ; Child Welfare/*history ; Female ; History, 17th Century ; History, 18th Century ; History, 19th Century ; Humans ; Intergenerational Relations ; Japan ; Logistic Models ; Male ; *Menopause ; Registries ; Survival Analysis ; }, abstract = {An unresolved question arising from human evolutionary research relates to the function of the postreproductive period in human females. If menopause is not merely an artifact resulting from the benefits of civilization, there must be an adaptive mechanism favoring the offspring of women who continue to thrive well past the time of their last ovulation. The "grandmother hypothesis" was developed on the basis of the original suggestion by Williams (1957 Evolution 11:32-39) that "stopping early" would benefit already-born children. This idea, combined with the concepts of kin selection (Hamilton 1964 J Theor Biol 7:1-52) and parental investment (Trivers 1972 Sexual Selection and the Descent of Man, Chicago: Aldine, p. 136-179), was expanded to suggest that postreproductive women (in contrast to males) contribute to their inclusive fitness by extending support to their grandchildren. We used discrete time event history analysis (Allison [1984] Event History Analysis, Newbury Park: Sage; Allison [1995] Survival Analysis, Cary, NC: SAS Institute) and logistic regression on data provided in population registers (Shūmon Aratame Chō, or SAC) from a village in central Japan, covering the period from 1671-1871, in a preliminary investigation of the effects of household grandparental presence on the probability of a child's death. We found that after accounting for the presence of other household members, the only grandparent whose presence exerted a consistent negative effect on the likelihood of a child's death was the mother's mother. Due to the small sample size of households that contained maternal grandmothers, these results failed to achieve statistical significance. Their importance, however, is in what they suggest about future research, i.e., census data from preindustrial societies can provide a basis for testing evolutionary proposals, including the "grandmother hypothesis."}, } @article {pmid12207730, year = {2002}, author = {Fournier, D and Aron, S and Milinkovitch, MC}, title = {Investigation of the population genetic structure and mating system in the ant Pheidole pallidula.}, journal = {Molecular ecology}, volume = {11}, number = {9}, pages = {1805-1814}, doi = {10.1046/j.1365-294x.2002.01573.x}, pmid = {12207730}, issn = {0962-1083}, mesh = {Animals ; Ants/*genetics/*physiology ; Female ; *Genetics, Population ; Genotype ; Male ; Microsatellite Repeats ; Regression Analysis ; Sexual Behavior, Animal/*physiology ; }, abstract = {The origin of eusociality in haplo-diploid organisms such as Hymenoptera has been mostly explained by kin selection. However, several studies have uncovered decreased relatedness values within colonies, resulting primarily from multiple queen matings (polyandry) and/or from the presence of more than one functional queen (polygyny). Here, we report on the use of microsatellite data for the investigation of sociogenetic parameters, such as relatedness, and levels of polygyny and polyandry, in the ant Pheidole pallidula. We demonstrate, through analysis of mother-offspring combinations and the use of direct sperm typing, that each queen is inseminated by a single male. The inbreeding coefficient within colonies and the levels of relatedness between the queens and their mate are not significantly different from zero, indicating that matings occur between unrelated individuals. Analyses of worker genotypes demonstrate that 38% of the colonies are polygynous with 2-4 functional queens, and suggest the existence of reproductive skew, i.e. unequal respective contribution of queens to reproduction. Finally, our analyses indicate that colonies are genetically differentiated and form a population exhibiting significant isolation-by-distance, suggesting that some colonies originate through budding.}, } @article {pmid12184886, year = {2002}, author = {Segal, NL and Sussman, LJ and Marelich, WD and Mearns, J and Blozis, SA}, title = {Monozygotic and dizygotic twins' retrospective and current bereavement-related behaviors: an evolutionary perspective.}, journal = {Twin research : the official journal of the International Society for Twin Studies}, volume = {5}, number = {3}, pages = {188-195}, doi = {10.1375/136905202320227844}, pmid = {12184886}, issn = {1369-0523}, mesh = {Adolescent ; Adult ; *Attitude to Death ; *Bereavement ; Biological Evolution ; Chi-Square Distribution ; Female ; Humans ; Male ; Retrospective Studies ; Twins, Dizygotic/genetics/*psychology ; Twins, Monozygotic/genetics/*psychology ; }, abstract = {The present study compared bereavement responses of 325 monozygotic (MZ) and 176 dizygotic (DZ) adolescent and adult twins following the loss of their co-twins. A subset of twins completed the Grief Experience Inventory using a retrospective time frame, while a second subset completed it using a current time frame. It was hypothesized that MZ twins (in both retrospective and current groups) would report higher levels of grief-related behavior than DZ twins, consistent with Hamilton's (1964) concept of inclusive fitness. Discriminant function and profile analyses yielded supportive findings, but only for the retrospective MZ and DZ twin comparisons. Females in both groups expressed higher levels of bereavement-related behavior than males. Findings are discussed with reference to theoretical aspects of grief and mourning.}, } @article {pmid12152077, year = {2002}, author = {Johnstone, RA}, title = {The evolution of inaccurate mimics.}, journal = {Nature}, volume = {418}, number = {6897}, pages = {524-526}, doi = {10.1038/nature00845}, pmid = {12152077}, issn = {0028-0836}, mesh = {Adaptation, Physiological ; Animals ; *Biological Evolution ; Discrimination Learning ; *Models, Biological ; Phenotype ; Predatory Behavior/*physiology ; Probability ; Selection, Genetic ; }, abstract = {Instances of strikingly accurate Batesian mimicry (in which a palatable prey organism closely resembles an aversive model) are often cited to illustrate the power of natural selection. Less attention has been paid to those mimics, such as many hoverfly (Syrphidae) mimics of wasps or bees, that resemble their models only poorly. Attempts to provide an adaptive explanation for imperfect mimicry have suggested that what seems a crude resemblance to human observers may appear a close match to predators, or that inaccurate mimics may bear a general resemblance to several different model species. I show here, however, that truly inaccurate mimicry of a single model organism may be favoured over perfect resemblance, by kin selection. Signal detection theory predicts that predators will modify their level of discrimination adaptively in response to the relative frequencies and similarity of models and mimics. If models are rare and/or weakly aversive, greater local similarity of mimics can thus lead to greater attack rates. Where individual mimics are related to others in their vicinity, kin selection will then oppose the evolution of accurate mimicry.}, } @article {pmid12115281, year = {2002}, author = {Roeder, JJ and Duval, L and Gosset, D}, title = {Aggressive and neutral interventions in conflicts in captive groups of brown lemurs (Eulemur fulvus fulvus).}, journal = {American journal of physical anthropology}, volume = {118}, number = {3}, pages = {253-258}, doi = {10.1002/ajpa.10066}, pmid = {12115281}, issn = {0002-9483}, mesh = {*Aggression ; Animals ; *Behavior, Animal ; Female ; Lemur/*psychology ; Male ; Sex Factors ; }, abstract = {Third-party interventions in conflicts have revealed complexity in primate social relationships. This type of intervention has seldom been analyzed in prosimians, although many of these species exhibit complex (multimale/multifemale) social organizations. The present study on captive brown lemurs (Eulemur fulvus fulvus) shows that dominant individuals were more likely to intervene in conflicts. Both males and females intervened aggressively in conflicts. Female aggressive interventions occurred mainly on behalf of close kin, whereas males mainly intervened on behalf of juveniles. This study also provides the first record of neutral or peaceful interventions in lemurs. Although females intervened neutrally, almost all neutral interventions were by dominant males. Dominant males intervened in conflicts neutrally more often than aggressively, principally in conflicts between adults and juveniles or between juveniles. Neutral interventions by males always ended the conflicts and were often followed by affiliative contacts between participants (intervenors and opponents). In lemurs, female interventions can be explained by kin selection, while the nature of dominant males' interventions suggests a control role. Interventions by males on behalf of juveniles may increase the formers' fitness.}, } @article {pmid12046624, year = {2002}, author = {Sanetra, M and Crozier, RH}, title = {Daughters inherit colonies from mothers in the 'living-fossil' ant Nothomyrmecia macrops.}, journal = {Die Naturwissenschaften}, volume = {89}, number = {2}, pages = {71-74}, doi = {10.1007/s00114-001-0288-5}, pmid = {12046624}, issn = {0028-1042}, mesh = {Animals ; Ants/*physiology ; Australia ; Female ; Fossils ; Male ; Reproduction ; Social Behavior ; }, abstract = {Newly mated queens of monogynous (single queen) ants usually found their colonies independently, without the assistance of workers. In polygynous (multiple queen) species queens are often adopted back into their natal nest and new colonies are established by budding. We report that the Australian 'living-fossil' ant, Nothomyrmecia macrops, is exceptional in that its single queen can be replaced by one of the colony's daughters. This type of colony founding is an interesting alternative reproductive strategy in monogynous ants, which maximizes fitness under kin selection. Successive queen replacement results in a series of reproductives over time (serial polygyny), making these colonies potentially immortal. Workers raise nieces and nephews (relatedness < or = 0.375) the year after queen replacement. Although N. macrops is 'primitive' in many other respects, colony inheritance is likely to be a derived specialization resulting from ecological constraints on solitary founding.}, } @article {pmid11997461, year = {2002}, author = {Alonso, WJ and Schuck-Paim, C}, title = {Sex-ratio conflicts, kin selection, and the evolution of altruism.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {99}, number = {10}, pages = {6843-6847}, pmid = {11997461}, issn = {0027-8424}, mesh = {Altruism ; Animals ; *Behavior, Animal ; *Biological Evolution ; Female ; Male ; Sex Ratio ; }, abstract = {Kin-selection theory has thrived in the explanation of a wide variety of biological phenomena, chiefly the evolution of biological altruism as that found in sterile castes of eusocial insects. Much of the way in which it has been tested is based on the existence of conflicts over sex-ratio production within eusocial colonies. However, despite neatly showing eusocial colonies as arenas where selection at the gene level triggers the appearance of sophisticated disputes, these studies have only demonstrated the existence of genes that act by biasing sex ratios to promote their own spread. Here we argue that such genes depend on the social organization of the colonies where they are expressed, but that they are not, in any way, the precursors of these societies-the major implication being that unequivocal evidence that eusociality evolved through the action of kin-selected altruistic genes is still lacking. Additionally, we highlight the neglect of alternative theories on the explanation of both biological altruism and sex-ratio conflicts, and defend that the enthusiasm with the latter has, in some cases, led to its inappropriate use as a basis for the explanation of other biological characteristics of eusocial organisms, when accounts based on phylogenetic or physiological constraints are also available.}, } @article {pmid11980046, year = {2002}, author = {Brüne, M}, title = {Toward an integration of interpersonal and biological processes: evolutionary psychiatry as an empirically testable framework for psychiatric research.}, journal = {Psychiatry}, volume = {65}, number = {1}, pages = {48-57}, doi = {10.1521/psyc.65.1.48.19759}, pmid = {11980046}, issn = {0033-2747}, mesh = {Adaptation, Psychological ; *Biological Evolution ; Humans ; Mental Disorders/*psychology ; Models, Biological ; Models, Psychological ; *Psychiatry ; *Research ; }, abstract = {Phenomenological, biological, and interpersonal aspects of psychiatric disorders lack an integrative empirical framework. In this paper evolutionary psychiatry is proposed as a meta-theory to integrate biological and interpersonal aspects of psychopathology. Pathological cognition, emotions, and behaviors may be examined according to specific biosocial goals originally pursued to increase the individual's inclusive fitness, similar to the ways that "normal" processes have been analyzed by evolutionary psychology. Sex-specific differences in prevalence rates and symptomatology of psychiatric disorders may also be better understood if divergent problems of adaptation for men and women in human evolutionary history are taken into account. Instead of mistaking the evolutionary approach for being deterministic and empirically untestable, it may rather be appropriate to provide a functional classification which adds to the contemporary psychiatric nosology through analysis according to specific conflicts of adaptation (at the ultimate level), the pursuit of biosocial goals, and proximate specifiers such as genetic, developmental, and interpersonal causes of disorders.}, } @article {pmid11959924, year = {2002}, author = {Giraud, T and Pedersen, JS and Keller, L}, title = {Evolution of supercolonies: the Argentine ants of southern Europe.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {99}, number = {9}, pages = {6075-6079}, pmid = {11959924}, issn = {0027-8424}, mesh = {Aggression ; Alleles ; Animals ; Ants/genetics/physiology ; *Biological Evolution ; Europe ; Genetic Variation ; }, abstract = {Some ants have an extraordinary social organization, called unicoloniality, whereby individuals mix freely among physically separated nests. This type of social organization is not only a key attribute responsible for the ecological domination of these ants, but also an evolutionary paradox and a potential problem for kin selection theory because relatedness between nest mates is effectively zero. The introduction of the Argentine ant in Europe was apparently accompanied by a dramatic loss of inter-nest aggression and the formation of two immense supercolonies (which effectively are two unicolonial populations). Introduced populations experienced only limited loss of genetic diversity at neutral markers, indicating that the breakdown of recognition ability is unlikely to be merely due to a genetic bottleneck. Rather, we suggest that a "genetic cleansing" of recognition cues occurred after introduction. Indeed workers of the same supercolony are never aggressive to each other despite the large geographical distance and considerable genetic differentiation between sampling sites. By contrast, aggression is invariably extremely high between the two supercolonies, indicating that they have become fixed for different recognition alleles. The main supercolony, which ranges over 6,000 km from Italy to the Spanish Atlantic coast, effectively forms the largest cooperative unit ever recorded.}, } @article {pmid11935015, year = {2002}, author = {West, SA and Pen, I and Griffin, AS}, title = {Cooperation and competition between relatives.}, journal = {Science (New York, N.Y.)}, volume = {296}, number = {5565}, pages = {72-75}, doi = {10.1126/science.1065507}, pmid = {11935015}, issn = {1095-9203}, mesh = {*Altruism ; Animals ; Biological Evolution ; Breeding ; *Competitive Behavior ; *Cooperative Behavior ; Female ; Male ; Mathematics ; Models, Psychological ; Population Dynamics ; Psychology, Social ; Reproduction ; }, abstract = {Individuals are predicted to behave more altruistically and less competitively toward their relatives, because they share a relatively high proportion of their genes (e.g., one-half for siblings and one-eighth for cousins). Consequently, by helping a relative reproduce, an individual passes its genes to the next generation, increasing their Darwinian fitness. This idea, termed kin selection, has been applied to a wide range of phenomena in systems ranging from replicating molecules to humans. Nevertheless, competition between relatives can reduce, and even totally negate, the kin-selected benefits of altruism toward relatives. Recent theoretical work has clarified the processes and selective forces underlying this effect and has demonstrated the generality of the effect of competition between relatives.}, } @article {pmid11935014, year = {2002}, author = {Clutton-Brock, T}, title = {Breeding together: kin selection and mutualism in cooperative vertebrates.}, journal = {Science (New York, N.Y.)}, volume = {296}, number = {5565}, pages = {69-72}, doi = {10.1126/science.296.5565.69}, pmid = {11935014}, issn = {1095-9203}, mesh = {Altruism ; Animals ; Behavior, Animal ; Biological Evolution ; *Breeding ; *Cooperative Behavior ; Female ; Male ; Reproduction ; *Social Behavior ; Vertebrates/*physiology ; }, abstract = {In cooperatively breeding vertebrates, nonbreeding helpers raise young produced by dominant breeders. Although the evolution of cooperative breeding has often been attributed primarily to kin selection (whereby individuals gain "indirect" benefits to their fitness by assisting collateral relatives), there is increasing evidence that helpers can be unrelated to the young they are raising. Recent studies also suggest that the indirect benefits of cooperative behavior may often have been overestimated while the direct benefits of helping to the helper's own fitness have probably been underestimated. It now seems likely that the evolutionary mechanisms maintaining cooperative breeding are diverse and that, in some species, the direct benefits of helping may be sufficient to maintain cooperative societies. The benefits of cooperation in vertebrate societies may consequently show parallels with those in human societies, where cooperation between unrelated individuals is frequent and social institutions are often maintained by generalized reciprocity.}, } @article {pmid11934364, year = {2002}, author = {Mateo, JM}, title = {Kin-recognition abilities and nepotism as a function of sociality.}, journal = {Proceedings. Biological sciences}, volume = {269}, number = {1492}, pages = {721-727}, pmid = {11934364}, issn = {0962-8452}, mesh = {Animals ; Discrimination, Psychological ; Female ; Male ; Models, Psychological ; Odorants ; Sciuridae/*genetics/*parasitology/physiology ; Smell ; *Social Behavior ; }, abstract = {Despite widespread interest in kin selection and nepotism, relatively little is known about the perceptual abilities of animals to recognize their relatives. Here I show that a highly nepotistic species, Belding's ground squirrels (Spermophilus beldingi), produces odours from at least two sources that correlate with relatedness ('kin labels'), and that ground squirrels can use these odours to make accurate discriminations among never before encountered ('unfamiliar') kin. Recognition odours appear to vary linearly with relatedness, rather than in an all-or-none fashion, allowing precise estimates of kinship even among distant relatives. Thus S. beldingi are able to recognize their distant kin and male kin, even though they do not treat them preferentially. I also show that a closely related species (S. lateralis) similarly produces kin labels and discriminates among kin, although it shows no evidence of kin-directed behaviour. Thus, contrary to a commonly held assumption, kin favouritism and recognition abilities can evolve independently, depending on variation in the costs and benefits of nepotism for a given species.}, } @article {pmid11919381, year = {2002}, author = {Schwartz, J}, title = {Population genetics and sociobiology: conflicting views of evolution.}, journal = {Perspectives in biology and medicine}, volume = {45}, number = {2}, pages = {224-240}, doi = {10.1353/pbm.2002.0039}, pmid = {11919381}, issn = {0031-5982}, mesh = {*Biological Evolution ; *Biology ; *Genetics, Population ; Humans ; *Models, Genetic ; Selection, Genetic ; }, abstract = {This article explores the tension between the population genetics and sociobiological approaches to the study of evolution. Whereas population geneticists, like Stanford's Marc Feldman, insist that the genetic complexities of organisms cannot be overlooked, sociobiologists (many of whom now prefer to call themselves "behavioral ecologists") rely on optimization models that are based on the simplest possible genetics.These optimization approaches have their roots in the classical result known as the fundamental theorem of natural selection, formulated by R. A. Fisher in 1930. From the start there was great uncertainty over the proper interpretation of Fisher's theorem, which became confused with Sewall Wright's immensely influential adaptive landscape concept. In the 1960s, a new generation of mathematical biologists proved that Fisher's theorem did not hold when fitness depended on more than one locus. Similar reasoning was used to attack W. D. Hamilton's inclusive fitness theory. A new theory, known as the theory of long-term evolution, attempts to reconcile the rigorous population genetics approach with the long-standing sociobiological view that natural selection acts to increase the fitness of organisms.}, } @article {pmid11918785, year = {2002}, author = {Valsecchi, E and Hale, P and Corkeron, P and Amos, W}, title = {Social structure in migrating humpback whales (Megaptera novaeangliae).}, journal = {Molecular ecology}, volume = {11}, number = {3}, pages = {507-518}, doi = {10.1046/j.0962-1083.2001.01459.x}, pmid = {11918785}, issn = {0962-1083}, mesh = {*Animal Migration ; Animals ; Behavior, Animal/*physiology ; DNA, Mitochondrial ; Family ; Female ; Gene Frequency ; Genotype ; Male ; Microsatellite Repeats ; Whales/*genetics/physiology ; }, abstract = {Although largely solitary, humpback whales exhibit a number of behaviours where individuals co-operate with one another, for example during bubble net feeding. Such cases could be due to reciprocal altruism brought on by exceptional circumstances, for example the presence of abundant shoaling fish. An alternative explanation is that these behaviours have evolved through kin selection. With little restriction to either communication or movement, diffuse groups of relatives could maintain some form of social organization without the need to travel in tight-nit units. To try to distinguish between these hypotheses, we took advantage of the fact that migrating humpback whales often swim together in small groups. If kin selection is important in humpback whale biology, these groups should be enriched for relatives. Consequently, we analysed biopsy samples from 57 groups of humpback whales migrating off Eastern Australia in 1992. A total of 142 whales were screened for eight microsatellite markers. Mitochondrial DNA sequences (371 bp) were also used to verify and assist kinship identification. Our data add support to the notion that mothers travel with their offspring for the first year of the calf's life. However, beyond the presence of mother-calf/yearling pairs, no obvious relatedness pattern was found among whales sampled either in the same pod or on the same day. Levels of relatedness did not vary between migratory phases (towards or away from the breeding ground), nor between the two sexes considered either overall or in the north or south migrations separately. These findings suggest that, if any social organization does exist, it is formed transiently when needed rather than being a constant feature of the population, and hence is more likely based on reciprocal altruism than kin selection.}, } @article {pmid11871266, year = {2001}, author = {Provorov, NA}, title = {[Genetic-evolutionary basis of symbiosis doctrine].}, journal = {Zhurnal obshchei biologii}, volume = {62}, number = {6}, pages = {472-495}, pmid = {11871266}, issn = {0044-4596}, mesh = {*Evolution, Molecular ; Phenotype ; *Symbiosis ; }, abstract = {The author presents the current notion of symbiosis as one of the main adaptation of an organism to changeable environment. Symbiosis is considered as a super organism genetic system within which there are different interactions (including mutualism and antagonism). Genetic integration of symbiotic partners can be realized as cross regulation of their genes, exchange of gene products (proteins, RNA), gene amplification and sometimes gene transfer between organisms. On the phenotypic level these processes result in signal interactions, integration of partner metabolic systems and development of symbiotic organs. Co-evolution is considered as an assemblage of micro- and macroevolution processes basing on pre-adaptations and proceeding under influence of different forms of natural selection (individual, frequency-depended and kin selection). Symbiosis can be compared with sexual process since both are the forms of organism integration characterized by different genetic mechanisms and evolutionary consequences. The genome evolution in symbiotic microorganisms can proceed by: 1) simplification of genome in obligate symbiosis (loss of genes that are necessary for independent existence, transfer of some genes to the host organism); 2) complication of genome in facultative symbiosis (increase in genome plasticity, structural and functional differentiation of genome into systems controlling free-living and symbiotic parts of life cycle). Most of symbiotic interactions are correlated to an increase in genetic plasticity of an organism that can lead to evolutionary saltations and origin of new forms of life.}, } @article {pmid11839195, year = {2002}, author = {Strassmann, JE and Sullender, BW and Queller, DC}, title = {Caste totipotency and conflict in a large-colony social insect.}, journal = {Proceedings. Biological sciences}, volume = {269}, number = {1488}, pages = {263-270}, pmid = {11839195}, issn = {0962-8452}, mesh = {Animals ; Base Sequence ; Female ; Male ; Ovary/growth & development ; Population Dynamics ; Reproduction/physiology ; *Social Behavior ; Wasps/anatomy & histology/growth & development/*physiology ; }, abstract = {In most social insects with large, complex colonies workers and queens are morphologically quite distinct. This means that caste determination must occur prior to adulthood. However workers and queens in the swarm-founding epiponine wasps are often morphologically indistinguishable, or nearly so, suggesting that caste determination in these wasps could be quite different. To determine the extent of caste lability in the epiponine, Parachartergus colobopterus, we removed all the queens from one colony and all but one from another colony. Worker aggression diminished after queen removal. A week later the colony with no queens had a new, young cohort of mated queens. These must have been either adults or pupae at the time of queen removal, and so could not have been fed any differently from workers. Relatedness patterns confirmed that these new queens would normally have been workers and not queens. A model of inclusive fitness interests shows that workers ought to suppress new queen production, except at low queen numbers, a prediction supported by our empirical results. The patterns of social conflict over queenship resulting from swarm founding in a many-queen society may help to explain the unusually weak caste differentiation in the epiponines.}, } @article {pmid11811801, year = {2002}, author = {Davies, CM and Fairbrother, E and Webster, JP}, title = {Mixed strain schistosome infections of snails and the evolution of parasite virulence.}, journal = {Parasitology}, volume = {124}, number = {Pt 1}, pages = {31-38}, doi = {10.1017/s0031182001008873}, pmid = {11811801}, issn = {0031-1820}, mesh = {Animals ; *Biological Evolution ; Biomphalaria/*parasitology ; Female ; Kenya ; Male ; Mice ; Mice, Inbred CBA ; Puerto Rico ; Random Allocation ; Schistosoma mansoni/genetics/growth & development/*pathogenicity ; Schistosomiasis mansoni/*parasitology/transmission ; Statistics, Nonparametric ; Virulence ; }, abstract = {Mathematical models often propose that within-host competition between parasites can be a major factor in the evolution of increased parasite virulence. Kin selection predicts that as the coefficient of relatedness between infecting parasites decreases, the benefits of competition to individual genotypes increases. Thus where parasites can adjust their behaviour in response to current conditions, higher virulence is predicted in multiple genotype infections. There is limited experimental data, however, regarding the effects of mixed strain infections on host and parasite fitness. We investigated, for a snail-schistosome system, whether a conditional increase in replication rates occurred in mixed genotype infections and resulted in increased virulence. Four groups of Biomphalaria glabrata snails were exposed to 1 or 2 laboratory strains of Schistosoma mansoni. Mixed genotype infections were observed to be more virulent than single genotype infections, in terms of reductions in host reproductive success and survival. Parasite reproductive rate was also increased in mixed strain groups. Reduced host reproductive success was suggested to be directly due to the genetic heterogeneity of the parasitic infections resulting in increased host defence costs. Reduced host survival was consistent with an adaptive conditional parasite response.}, } @article {pmid11805825, year = {2002}, author = {Fehr, E and Gächter, S}, title = {Altruistic punishment in humans.}, journal = {Nature}, volume = {415}, number = {6868}, pages = {137-140}, doi = {10.1038/415137a}, pmid = {11805825}, issn = {0028-0836}, mesh = {*Altruism ; *Biological Evolution ; *Cooperative Behavior ; Emotions ; Female ; Games, Experimental ; Humans ; Male ; *Punishment ; }, abstract = {Human cooperation is an evolutionary puzzle. Unlike other creatures, people frequently cooperate with genetically unrelated strangers, often in large groups, with people they will never meet again, and when reputation gains are small or absent. These patterns of cooperation cannot be explained by the nepotistic motives associated with the evolutionary theory of kin selection and the selfish motives associated with signalling theory or the theory of reciprocal altruism. Here we show experimentally that the altruistic punishment of defectors is a key motive for the explanation of cooperation. Altruistic punishment means that individuals punish, although the punishment is costly for them and yields no material gain. We show that cooperation flourishes if altruistic punishment is possible, and breaks down if it is ruled out. The evidence indicates that negative emotions towards defectors are the proximate mechanism behind altruistic punishment. These results suggest that future study of the evolution of human cooperation should include a strong focus on explaining altruistic punishment.}, } @article {pmid11798433, year = {2002}, author = {Hammond, RL and Bruford, MW and Bourke, AF}, title = {Ant workers selfishly bias sex ratios by manipulating female development.}, journal = {Proceedings. Biological sciences}, volume = {269}, number = {1487}, pages = {173-178}, pmid = {11798433}, issn = {0962-8452}, mesh = {Animals ; Ants/*physiology ; Diploidy ; Female ; Haploidy ; Male ; Sex Ratio ; }, abstract = {Kin selection theory predicts that social insects should perform selfish manipulations as a function of colony genetic structure. We describe a novel mechanism by which this occurs. First, we use microsatellite analyses to show that, in a population of the ant Leptothorax acervorum, workers' relatedness asymmetry (ratio of relatedness to females and relatedness to males) is significantly higher in monogynous (single-queen) colonies than in polygynous (multiple-queen) colonies. Workers rear mainly queens in monogynous colonies and males in polygynous colonies. Therefore, split sex ratios in this population are correlated with workers' relatedness asymmetry. Together with significant female bias in the population numerical and investment sex ratios, this finding strongly supports kin-selection theory. Second, by determining the primary sex ratio using microsatellite markers to sex eggs, we show that the ratio of male to female eggs is the same in both monogynous and polygynous colonies and equals the overall ratio of haploids (males) to diploids (queens and workers) among adults. In contrast to workers of species with selective destruction of male brood, L. acervorum workers therefore rear eggs randomly with respect to sex and must achieve their favoured sex ratios by selectively biasing the final caste (queen or worker) of developing females.}, } @article {pmid11742549, year = {2001}, author = {Paxton, RJ and Thorén, PA and Estoup, A and Tengö, J}, title = {Queen-worker conflict over male production and the sex ratio in a facultatively polyandrous bumblebee, Bombus hypnorum: the consequences of nest usurpation.}, journal = {Molecular ecology}, volume = {10}, number = {10}, pages = {2489-2498}, pmid = {11742549}, issn = {0962-1083}, mesh = {Animals ; Bees/*genetics/*physiology ; Female ; Male ; Microsatellite Repeats/genetics ; Reproduction ; Sex Ratio ; Sexual Behavior, Animal/*physiology ; }, abstract = {Evolutionary conflicts among social hymenopteran nestmates are theoretically likely to arise over the production of males and the sex ratio. Analysis of these conflicts has become an important focus of research into the role of kin selection in shaping social traits of hymenopteran colonies. We employ microsatellite analysis of nestmates of one social hymenopteran, the primitively eusocial and monogynous bumblebee Bombus hypnorum, to evaluate these conflicts. In our 14 study colonies, B. hypnorum queens mated between one and six times (arithmetic mean 2.5). One male generally predominated, fathering most of the offspring, thus the effective number of matings was substantially lower (1-3.13; harmonic mean 1.26). In addition, microsatellite analysis allowed the detection of alien workers, those who could not have been the offspring of the queen, in approximately half the colonies. Alien workers within the same colony were probably sisters. Polyandry and alien workers resulted in high variation among colonies in their sociogenetic organization. Genetic data were consistent with the view that all males (n = 233 examined) were produced by a colony's queen. Male parentage was therefore independent of the sociogenetic organization of the colony, suggesting that the queen, and not the workers, was in control of the laying of male-destined eggs. The population-wide sex ratio (fresh weight investment ratio) was weakly female biased. No evidence for colony-level adaptive sex ratio biasing could be detected.}, } @article {pmid11723630, year = {2001}, author = {Gilbert, P}, title = {Evolution and social anxiety. The role of attraction, social competition, and social hierarchies.}, journal = {The Psychiatric clinics of North America}, volume = {24}, number = {4}, pages = {723-751}, doi = {10.1016/s0193-953x(05)70260-4}, pmid = {11723630}, issn = {0193-953X}, mesh = {Animals ; Anxiety/*psychology ; Anxiety Disorders/psychology ; Awareness ; *Biological Evolution ; Female ; Humans ; Male ; Models, Psychological ; Phobic Disorders/psychology ; *Self Concept ; *Social Behavior ; *Social Desirability ; *Social Dominance ; }, abstract = {If human social anxiety is not predominately about the fear of physical injury or attack, as it is in other animals, then, to understand human social anxiety (i.e., fear of evaluation), it is necessary to consider why certain types of relationships are so important. Why do humans need to court the good feelings of others and fear not doing so? And why, when people wish to appear attractive to others (e.g., to make friends, date a desired sexual partner, or give a good presentation), do some people become so overwhelmed with anxiety that they behave submissively and fearfully (which can be seen as unattractive) or are avoidant? This article has suggested that humans have evolved to compete for attractiveness to make good impressions because these are related to eliciting important social resources and investments from others. These, in turn, have been linked to inclusive fitness and have physiological regulating effects. Being allocated a low social rank or ostracized carries many negative consequences for controlling social resources and physiological regulation. Social anxiety, like shame, can be adaptive to the extent that it helps people to "stay on track" with what is socially acceptable and what is not and could result in social sanction and exclusion. However, dysfunctional social anxiety is the result of activation of basic defensive mechanisms (and modules for) for threat detection and response (e.g., inhibition, eye-gaze avoidance, flight, or submission) that can be recruited rapidly for dealing with immediate threats, override conscious wishes, and interfere with being seen as a "useful associate." Second, this article has suggested that socially anxious people are highly attuned to the competitive dynamics of trying to elicit approval and investment from others but that they perceive themselves to start from an inferior (i.e., low-rank) position and, because of this, activate submissive defensives when attempting to present themselves as confident, able, and attractive to others. These submissive defenses (which evolved to inhibit animals in low-rank positions from making claims on resources or up-rank bids) interfere with confident performance, leading to a failure cycle. While psychological therapies may target specific modules, cognitions, and behaviors (e.g., damage limitation behaviors, eyes gaze avoidance, theory of mind beliefs) that underpin social anxiety, drugs may work by having a more generalized effect on the threat-safety balance such that there is a different "weighting" given to various social threats and opportunities. If social anxiety (and disorders associated with it) are increasing in the modern age, one reason may be invigorated competition for social prestige, attractiveness, and resources.}, } @article {pmid11719803, year = {2001}, author = {Riolo, RL and Cohen, MD and Axelrod, R}, title = {Evolution of cooperation without reciprocity.}, journal = {Nature}, volume = {414}, number = {6862}, pages = {441-443}, doi = {10.1038/35106555}, pmid = {11719803}, issn = {0028-0836}, mesh = {Altruism ; Animals ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Models, Biological ; }, abstract = {A long-standing problem in biological and social sciences is to understand the conditions required for the emergence and maintenance of cooperation in evolving populations. For many situations, kin selection is an adequate explanation, although kin-recognition may still be a problem. Explanations of cooperation between non-kin include continuing interactions that provide a shadow of the future (that is, the expectation of an ongoing relationship) that can sustain reciprocity, possibly supported by mechanisms to bias interactions such as embedding the agents in a two-dimensional space or other context-preserving networks. Another explanation, indirect reciprocity, applies when benevolence to one agent increases the chance of receiving help from others. Here we use computer simulations to show that cooperation can arise when agents donate to others who are sufficiently similar to themselves in some arbitrary characteristic. Such a characteristic, or 'tag', can be a marking, display, or other observable trait. Tag-based donation can lead to the emergence of cooperation among agents who have only rudimentary ability to detect environmental signals and, unlike models of direct or indirect reciprocity, no memory of past encounters is required.}, } @article {pmid11703514, year = {2001}, author = {Keller, L and Liautard, C and Reuter, M and Brown, WD and Sundström, L and Chapuisat, M}, title = {Sex ratio and Wolbachia infection in the ant Formica exsecta.}, journal = {Heredity}, volume = {87}, number = {Pt 2}, pages = {227-233}, doi = {10.1046/j.1365-2540.2001.00918.x}, pmid = {11703514}, issn = {0018-067X}, mesh = {Animals ; Ants/*microbiology ; Female ; Male ; Polymerase Chain Reaction ; Sex Ratio ; Wolbachia/*physiology ; }, abstract = {Sex allocation data in social Hymenoptera provide some of the best tests of kin selection, parent-offspring conflict and sex ratio theories. However, these studies critically depend on controlling for confounding ecological factors and on identifying all parties that potentially manipulate colony sex ratio. It has been suggested that maternally inherited parasites may influence sex allocation in social Hymenoptera. If the parasites can influence sex allocation, infected colonies are predicted to invest more resources in females than non-infected colonies, because the parasites are transmitted through females but not males. Prime candidates for such sex ratio manipulation are Wolbachia, because these cytoplasmically transmitted bacteria have been shown to affect the sex ratio of host arthropods by cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. In this study, we tested whether Wolbachia infection is associated with colony sex ratio in two populations of the ant Formica exsecta that have been the subject of extensive sex ratio studies. In these populations colonies specialize in the production of one sex or the other. We found that almost all F. exsecta colonies in both populations are infected with Wolbachia. However, in neither population did we find a significant association in the predicted direction between the prevalence of Wolbachia and colony sex ratio. In particular, colonies with a higher proportion of infected workers did not produce more females. Hence, we conclude that Wolbachia does not seem to alter the sex ratio of its hosts as a means to increase transmission rate in these two populations of ants.}, } @article {pmid11698652, year = {2001}, author = {Widdig, A and Nürnberg, P and Krawczak, M and Streich, WJ and Bercovitch, FB}, title = {Paternal relatedness and age proximity regulate social relationships among adult female rhesus macaques.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {98}, number = {24}, pages = {13769-13773}, pmid = {11698652}, issn = {0027-8424}, mesh = {Age Factors ; Animals ; Female ; Macaca mulatta ; Male ; *Paternity ; *Social Behavior ; }, abstract = {Kin selection promotes the evolution of social behavior that increases the survival and reproductive success of close relatives. Among primates, maternal kinship frequently coincides with a higher frequency of grooming and agonistic aiding, but the extent to which paternal kinship influences adult female social relationships has not yet been investigated. Here, we examine the effect of both maternal and paternal kinship, as well as age proximity, on affiliative interactions among semifree-ranging adult female rhesus macaques, Macaca mulatta. Kinship was assessed by using both microsatellites and DNA-fingerprinting. Our study confirms that the closest affiliative relationships characterize maternal half-sisters. We provide evidence that adult females are significantly more affiliative with paternal half-sisters than with nonkin. Furthermore, paternal kin discrimination was more pronounced among peers than among nonpeers, indicating that age proximity has an additional regulatory effect on affiliative interactions. We propose that kin discrimination among cercopithecine primates emerges from ontogenetic processes that involve phenotype matching based on shared behavioral traits, such as inherited personality profiles, rather than physiological or physical characteristics.}, } @article {pmid11600082, year = {2001}, author = {Russell, AF and Hatchwell, BJ}, title = {Experimental evidence for kin-biased helping in a cooperatively breeding vertebrate.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1481}, pages = {2169-2174}, pmid = {11600082}, issn = {0962-8452}, mesh = {Animals ; Breeding ; *Cooperative Behavior ; Female ; *Helping Behavior ; Male ; *Reproduction ; Sexual Behavior, Animal ; Songbirds/*physiology ; }, abstract = {The widespread belief that kin selection is necessary for the evolution of cooperative breeding in vertebrates has recently been questioned. These doubts have primarily arisen because of the paucity of unequivocal evidence for kin preferences in cooperative behaviour. Using the cooperative breeding system of long-tailed tits (Aegithalos caudatus) in which kin and non-kin breed within each social unit and helpers are failed breeders, we investigated whether helpers preferentially direct their care towards kin following breeding failure. First, using observational data, we show that not all failed breeders actually become helpers, but that those that do help usually do so at the nest of a close relative. Second, we confirm the importance of kinship for helping in this species by conducting a choice experiment. We show that potential helpers do not become helpers in the absence of close kin and, when given a choice between helping equidistant broods belonging to kin and non-kin within the same social unit, virtually all helped at the nest of kin. This study provides strong evidence that kinship plays an essential role in the maintenance of cooperative breeding in this species.}, } @article {pmid11586357, year = {2001}, author = {Riipi, M and Alatalo, RV and Lindström, L and Mappes, J}, title = {Multiple benefits of gregariousness cover detectability costs in aposematic aggregations.}, journal = {Nature}, volume = {413}, number = {6855}, pages = {512-514}, doi = {10.1038/35097061}, pmid = {11586357}, issn = {0028-0836}, mesh = {Animals ; Behavior, Animal ; Biological Evolution ; Learning ; Predatory Behavior ; Songbirds/*physiology ; }, abstract = {Understanding the early evolution of aposematic (warning) coloration has been a challenge for scientists, as a new conspicuous morph in a population of cryptic insects would have a high predation risk and would probably die out before local predators learnt to avoid it. Fisher presented the idea of aggregation benefit through the survival of related individuals; however, his theory has been strongly debated as the mechanisms that favour grouping have never been explored experimentally with the incorporation of detectability costs. Here we create a comprehensive 'novel world' experiment with the great tit (Parus major) as a predator to explore simultaneously the predation-related benefits and costs for aposematic aggregated prey, manipulating both group size and signal strength. Our results show that grouping would have been highly beneficial for the first aposematic prey individuals surrounded by naive predators, because (1) detectability risk increased only asymptotically with group size; (2) additional detectability costs due to conspicuous signals were marginal in groups; (3) even naive predators deserted the group after detecting unpalatability (dilution effect); and (4) avoidance learning of signal was faster in groups. None of these mechanisms require kin selection.}, } @article {pmid11584133, year = {2001}, author = {Bourke, AF}, title = {Social insects and selfish genes.}, journal = {Biologist (London, England)}, volume = {48}, number = {5}, pages = {205-208}, pmid = {11584133}, issn = {0006-3347}, mesh = {Altruism ; Animals ; Behavior, Animal ; Biological Evolution ; Family ; Insecta/*genetics/physiology ; Microsatellite Repeats/genetics ; Reproduction/genetics ; *Selection, Genetic ; Social Behavior ; }, abstract = {Sometimes science advances because of a new idea. Sometimes, it's because of a new technique. When both occur together, exciting times result. In the study of social insects, DNA-based methods for measuring relatedness now allow increasingly detailed tests of Hamilton's theory of kin selection.}, } @article {pmid20043376, year = {2001}, author = {MacDonald, DH}, title = {Grief and burial in the American Southwest: the role of evolutionary theory in the interpretation of mortuary remains.}, journal = {American antiquity}, volume = {66}, number = {4}, pages = {704-714}, pmid = {20043376}, issn = {0002-7316}, mesh = {Attitude to Death/ethnology ; Biological Evolution ; *Funeral Rites/history/psychology ; *Grief ; History, Ancient ; Humans ; Indians, North American/*history/*psychology ; Mexico ; Mortuary Practice/history/methods/trends ; Southwestern United States ; }, abstract = {Evolutionary theory, in consort with Marxism and processualism, provides new insights into the interpretation of grave-good variation. Processual interpretations of burial sites in the American Southwest cite age, sex, or social rank as the main determinants of burial-good variation. Marxist theorists suggest that mortuary ritual mediates social tension between an egalitarian mindset and an existing social inequality. Evolutionary theory provides a supplementary explanatory framework. Recent studies guided by kin-selection theory suggest that humans grieve more for individuals of high reproductive value and genetic relatedness. Ethnographic examples also show that individuals mourn more intensively and, thus, place more social emphasis on burials of individuals of highest reproductive value (young adults). Analysis of grave goods from La Ciudad, a Hohokam site in the American Southwest, supports the hypothesis that labor value, reproductive value, and grief contributed to grave-good differentiation. At La Ciudad, individuals between the ages of 10 and 20 possessed more and higher-quality grave goods on average than any other age group. Grief at the loss of a young adult of high reproductive and labor value may facilitate explanation of mortuary variation at La Ciudad, as well as other sites in the greater Southwest and beyond.}, } @article {pmid11564355, year = {2001}, author = {Cant, MA and Field, J}, title = {Helping effort and future fitness in cooperation animal societies.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1479}, pages = {1959-1964}, doi = {10.1098/rspb.2001.1754}, pmid = {11564355}, issn = {0962-8452}, mesh = {*Adaptation, Physiological ; Animals ; *Cooperative Behavior ; *Helping Behavior ; Models, Biological ; *Wasps ; }, abstract = {Little attention has been paid to a conspicuous and universal feature of animal societies: the variation between individuals in helping effort. Here, we develop a multiplayer kin-selection model that assumes that subordinates face a trade-off because current investment in help reduces their own future reproductive success. The model makes two predictions: (i) subordinates will work less hard the closer they are to inheriting breeding status; and (ii) for a given dominance rank, subordinates will work less hard in larger groups. The second prediction reflects the larger pay-off from inheriting a larger group. Both predictions were tested through a field experiment on the paper wasp Polistes dominulus. First, we measured an index of helping effort among subordinates, then we removed successive dominants to reveal the inheritance ranks of the subordinates: their positions in the queue to inherit dominance. We found that both inheritance rank and group size had significant effects on helping effort, in the manner predicted by our model. The close match between our theoretical and empirical results suggests that individuals adjust their helping effort according to their expected future reproductive success. This relationship has probably remained hidden in previous studies that have focused on variation in genetic relatedness.}, } @article {pmid11564352, year = {2001}, author = {Möller, LM and Beheregaray, LB and Harcourt, RG and Krützen, M}, title = {Alliance membership and kinship in wild male bottlenose dolphins (Tursiops aduncus) of southeastern Australia.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1479}, pages = {1941-1947}, doi = {10.1098/rspb.2001.1756}, pmid = {11564352}, issn = {0962-8452}, mesh = {Animals ; Australia ; *Behavior, Animal ; *Cooperative Behavior ; DNA, Mitochondrial/analysis ; Dolphins/classification/*genetics/physiology ; Male ; Nuclear Family ; }, abstract = {Bottlenose dolphins are one of only a few mammalian taxa where the males are known to cooperate within their social group in order to maintain mating access to single females against other males. Male bonds in bottlenose dolphins have been hypothesized as evolving through kinship and associated inclusive fitness effects. In this study we tested whether individually identified male bottlenose dolphins preferentially associate and form alliances with kin in a small coastal resident population of southeastern Australia using a combination of behavioural data, genetic sexing, sequences of the mitochondrial DNA control region and nuclear microsatellite markers. Males generally associated significantly more often than expected with one to three other males, with whom they jointly herded females for mating. Associations and alliance membership were not associated with either maternal kinship or genetic relatedness. The majority of male pairs within alliances were randomly related, although high relatedness values were found between males of different alliances in the resident population. These findings indicate that mechanisms other than kin selection may be foremost in the development and maintenance of cooperation between male bottlenose dolphins.}, } @article {pmid11562469, year = {2001}, author = {Abbot, P and Withgott, JH and Moran, NA}, title = {Genetic conflict and conditional altruism in social aphid colonies.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {98}, number = {21}, pages = {12068-12071}, pmid = {11562469}, issn = {0027-8424}, mesh = {Animals ; Aphids/*genetics/physiology ; Behavior, Animal/*physiology ; Genetic Markers ; Polymerase Chain Reaction/methods ; Polymorphism, Restriction Fragment Length ; *Social Behavior ; }, abstract = {Although kin selection is central to the modern study of social evolution, recent studies of social species have revealed that no simple relationship exists between levels of kinship and sociality. The soldier-producing aphids are unique among highly social animals because, barring movement by aphids between colonies, they occur in clonal groups of genetically identical individuals. Potentially, clonality simplifies efforts to understand social evolution in aphids by obviating issues of intragroup conflict. However, we report here high levels of clonal mixing and conflict in an aphid society. The gall-dwelling colonies of a social aphid species (Pemphigus obesinymphae) are not pure clones, but are invaded by large numbers of aphids from other clones. Intruders behave and develop selfishly once they have invaded a colony of nonkin. They refrain from risky defensive behaviors and accelerate their own development into reproductive rather than defensive stages. This conditionality in the social life of P. obesinymphae reveals complex dynamics and a degree of behavioral plasticity not previously known in aphid societies.}, } @article {pmid11554967, year = {2001}, author = {Sundström, L and Boomsma, JJ}, title = {Conflicts and alliances in insect families.}, journal = {Heredity}, volume = {86}, number = {Pt 5}, pages = {515-521}, doi = {10.1046/j.1365-2540.2001.00884.x}, pmid = {11554967}, issn = {0018-067X}, mesh = {Animals ; Biological Evolution ; *Conflict, Psychological ; Female ; Insecta/*genetics/*physiology ; Male ; Models, Biological ; Reproduction ; Selection, Genetic ; Sex Ratio ; *Social Behavior ; }, abstract = {Hamilton's principle of inclusive fitness implies that reproductive altruism can evolve, because individuals can pass on genes not only through their own offspring, but also through the offspring of their relatives. Social insects are spectacular examples of how some individuals may be selected to forgo reproduction and instead help others reproduce. Social Hymenoptera are also special because relatedness patterns within families can be asymmetrical, so that optimal sex-ratios, preferred male parentage or preferred mating frequencies become objects of reproductive conflict. The now extensive inclusive fitness theory provides precise qualitative predictions with respect to the emergence of such conflicts. Recent advances in the power of genetic markers applied to resolve family structure in insect societies have brought about a series of studies that have tested these predictions. In support of kin selection as a major evolutionary force, the results suggest that workers frequently control sex allocation. However, the very establishment of such worker control has made new conflicts come to light, between mothers and fathers and between adult individuals and brood. Evidence for these conflicts is only just beginning to be gathered. Recent studies tend to include issues such as 'information' and 'power' (i.e. the ability to perceive signals and the opportunity to act upon this information), and to address selection for selfishness at the individual level with costs of social disruption at the colony level.}, } @article {pmid11535648, year = {2001}, author = {Goodisman, MA and Matthews, RW and Spradbery, JP and Carew, ME and Crozier, RH}, title = {Reproduction and recruitment in perennial colonies of the introduced wasp Vespula germanica.}, journal = {The Journal of heredity}, volume = {92}, number = {4}, pages = {346-349}, doi = {10.1093/jhered/92.4.346}, pmid = {11535648}, issn = {0022-1503}, mesh = {Animals ; Female ; Male ; Reproduction ; *Sexual Behavior, Animal ; Wasps/genetics/*physiology ; }, abstract = {We investigated the genetic structure of perennial colonies of the yellowjacket wasp (Vespula germanica) in its introduced range in Australia and New Zealand. The nuclear genotypes of 712 gynes from 21 colonies, 147 workers from 5 colonies, and 81 males from 4 colonies were assayed at three polymorphic microsatellite loci. The mitochondrial haplotypes of all wasps also were determined for a 450-bp region of the mtDNA using double-stranded conformational polymorphism (DSCP) analysis. We found that multiple reproductives were needed to explain the genotypes of gynes, workers, and males in 7 of 21, 2 of 5, and 2 of 4 colonies, respectively, and that nestmate relatedness of these three castes equaled 0.42, 0.16, and 0.22, respectively. The mitochondrial data revealed that all individuals shared the same mtDNA haplotype in 20 of the 21 colonies. However, in one colony, gynes and workers displayed multiple mtDNA haplotypes, indicating that nonnestmate recruitment had occurred. Overall the genetic structure within the majority of perennial colonies conformed to expectations based on the biology of V. germanica and kin selection theory for polygyne colonies; multiple reproductives successfully produced offspring and were recruited into their natal nests, thereby maintaining relatively high relatedness between interacting individuals.}, } @article {pmid11475057, year = {2001}, author = {Storz, JF and Bhat, HR and Kunz, TH}, title = {Genetic consequences of polygyny and social structure in an Indian fruit bat, Cynopterus sphinx. I. Inbreeding, outbreeding, and population subdivision.}, journal = {Evolution; international journal of organic evolution}, volume = {55}, number = {6}, pages = {1215-1223}, doi = {10.1111/j.0014-3820.2001.tb00641.x}, pmid = {11475057}, issn = {0014-3820}, mesh = {Animals ; Breeding ; Chiroptera/classification/*genetics ; *Crosses, Genetic ; DNA Primers ; Female ; *Genetic Variation ; Genetics, Population ; Genotype ; India ; Linkage Disequilibrium ; Male ; Microsatellite Repeats/genetics ; Polymerase Chain Reaction/methods ; Sequence Analysis, DNA ; }, abstract = {Population subdivision into behaviorally cohesive kin groups influences rates of inbreeding and genetic drift and has important implications for the evolution of social behavior. Here we report the results of a study designed to test the hypothesis that harem social structure promotes inbreeding and genetic subdivision in a population with overlapping generations. Genetic consequences of harem social structure were investigated in a natural population of a highly polygynous fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae), in western India. The partitioning of genetic variance within and among breeding groups was assessed using 10-locus microsatellite genotypes for 431 individually marked bats. Genetic analysis of the C. sphinx study population was integrated with field data on demography and social structure to determine the specific ways in which mating, dispersal, and new social group formation influenced population genetic structure. Microsatellite data revealed striking contrasts in genetic structure between consecutive offspring cohorts and between generations. Relative to the 1998 (dry-season) offspring cohort, the 1997 (wet-season) cohort was characterized by a more extensive degree of within-group heterozygote excess (F(IS) = -0.164 vs. -0.050), a greater degree of among-group subdivision (F(ST) = 0.123 vs. 0.008), and higher average within-group relatedness (r = 0.251 vs. 0.017). Differences in genetic structure between the two offspring cohorts were attributable to seasonal differences in the number and proportional representation of male parents. Relative to adult age-classes, offspring cohorts were characterized by more extensive departures from allelic and genotypic equilibria and a greater degree of genetic subdivision. Generational differences in F-statistics indicated that genetic structuring of offspring cohorts was randomized by natal dispersal prior to recruitment into the breeding population. Low relatedness among harem females (r = 0.002-0.005) was primarily attributable to high rates of natal dispersal and low rates of juvenile survivorship. Kin selection is therefore an unlikely explanation for the formation and maintenance of behaviorally cohesive breeding groups in this highly social mammal.}, } @article {pmid11449816, year = {2001}, author = {Kramer, DA}, title = {The biology of family psychotherapy.}, journal = {Child and adolescent psychiatric clinics of North America}, volume = {10}, number = {3}, pages = {625-640}, pmid = {11449816}, issn = {1056-4993}, mesh = {Adolescent ; Animals ; Brain/*physiopathology ; Child ; Child Behavior Disorders/physiopathology/psychology/*therapy ; Child of Impaired Parents/psychology ; *Family Therapy ; Humans ; Personality Development ; Social Environment ; }, abstract = {This article has presented a view of biologic psychiatry consistent with that described by Bowlby, discussed hypotheses concerning the biologic purpose of the primate brain and the human brain, and challenged standard beliefs about the identity of the patient entity in a true biologically based psychiatry. Ideas developed by Whitaker, Malone, and their colleagues almost 50 years ago are consistent with a modern biologic basis of family psychotherapy. The treatment of an anorexic family was used to illustrate possible mechanisms of psychotherapeutic treatment requiring the presence of the whole family. The role of the psychiatrist who treats a family is to understand the biologic or medical importance of treating the family as a whole, communicate this to the family, continually work toward that level of participation, suggest relevant topics for discussion, and catalyze interactions within the family. Psychotherapy with families as a whole is effective because of the power of kin selection and inclusive fitness, biologic processes not usually considered in the practice of medicine or psychiatry.}, } @article {pmid11438373, year = {2001}, author = {Troisi, A}, title = {Gender differences in vulnerability to social stress: a Darwinian perspective.}, journal = {Physiology & behavior}, volume = {73}, number = {3}, pages = {443-449}, doi = {10.1016/s0031-9384(01)00459-0}, pmid = {11438373}, issn = {0031-9384}, mesh = {Animals ; *Biological Evolution ; Dominance-Subordination ; Female ; Humans ; Male ; Sex Characteristics ; Stress, Psychological/*psychology ; }, abstract = {This article offers a theoretical framework based on evolutionary thinking designed to clarify relationships between social stress and mental illness, including the origin of gender differences in vulnerability to stress. From a Darwinian perspective, stress is an interference with evolved behavioral strategies. Human behavior is organized around the pursuit of biological goals, and any social event that interferes with these evolved strategic goals may constitute a stressor. The response to such interference -- the stress response -- is made up of physiological, psychological and behavioral components. These components determine how individuals deal with those social events that were likely to reduce inclusive fitness in the ancestral environment. Evolved gender differences in commitment to goals play a role in determining individual differences in response to stressors. When a social stressor interferes with achieving a biological goal, its harmful impact will depend primarily on the importance of the goal to an individual, and the importance assigned to different goals by an individual does not depend exclusively on personal variables and cultural values. Two evolutionary theories are relevant to gender differences in vulnerability to social stress: sexual selection theory and life history theory. Clinical data from patients suffering from depression triggered by social stress are reviewed to test predictions derived from these theories.}, } @article {pmid11437312, year = {2001}, author = {Korchmaros, JD and Kenny, DA}, title = {Emotional closeness as a mediator of the effect of genetic relatedness on altruism.}, journal = {Psychological science}, volume = {12}, number = {3}, pages = {262-265}, doi = {10.1111/1467-9280.00348}, pmid = {11437312}, issn = {0956-7976}, support = {R01-51964//PHS HHS/United States ; }, mesh = {Adult ; *Affect ; *Altruism ; Female ; Genetic Predisposition to Disease/*psychology ; Humans ; *Interpersonal Relations ; Male ; Models, Biological ; Surveys and Questionnaires ; }, abstract = {Inclusive fitness theory has been used to explain the overall pattern of altruistic behavior. However, this theory does not address the proximal causes of altruism. The purpose of the present study was to increase the understanding of altruism by testing a model that includes both ultimate and proximate causes. In particular, emotional closeness was tested as a mediator of the effect of genetic relatedness on altruistic behavior. This was accomplished by having college students choose which of their family members they would most likely provide with life-saving assistance. As expected, results showed that emotional closeness is an important proximal cause of altruism that partially mediates the effect of genetic relatedness on willingness to act altruistically.}, } @article {pmid11430657, year = {2001}, author = {Tsutsui, ND and Case, TJ}, title = {Population genetics and colony structure of the Argentine ant (Linepithema humile) in its native and introduced ranges.}, journal = {Evolution; international journal of organic evolution}, volume = {55}, number = {5}, pages = {976-985}, doi = {10.1554/0014-3820(2001)055[0976:pgacso]2.0.co;2}, pmid = {11430657}, issn = {0014-3820}, mesh = {Animals ; Ants/*genetics/physiology ; Argentina ; Evolution, Molecular ; Genetic Variation ; Genetics, Population ; Microsatellite Repeats ; Social Behavior ; Species Specificity ; }, abstract = {Introduced species often possess low levels of genetic diversity relative to source populations as a consequence of the small population sizes associated with founder events. Additionally, native and introduced populations of the same species can possess divergent genetic structuring at both large and small geographic scales. Thus, genetic systems that have evolved in the context of high diversity may function quite differently in genetically homogeneous introduced populations. Here we conduct a genetic analysis of native and introduced populations of the Argentine ant (Linepithema humile) in which we show that the population-level changes that have occurred during introduction have produced marked changes in the social structure of this species. Native populations of the Argentine ant are characterized by a pattern of genetic isolation by distance, whereas this pattern is absent in introduced populations. These differences appear to arise both from the effects of recent range expansion in the introduced range as well as from differences in gene flow within each range. Relatedness within nests and colonies is lower in the introduced range than in the native range as a consequence of the widespread genetic similarity that typifies introduced populations. In contrast, nestmates and colony-mates in the native range are more closely related, and local genetic differentiation is evident. Our results shed light on the problem posed for kin selection theory by the low levels of relatedness that are characteristic of many unicolonial species and suggest that the loss of genetic variation may be a common mechanism for the transition to a unicolonial colony structure.}, } @article {pmid11429136, year = {2001}, author = {Combes, SL and Altmann, J}, title = {Status change during adulthood: life-history by-product or kin selection based on reproductive value?.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1474}, pages = {1367-1373}, doi = {10.1098/rspb.2001.1631}, pmid = {11429136}, issn = {0962-8452}, mesh = {*Aging ; Animals ; *Behavior, Animal ; Female ; *Papio ; }, abstract = {When dominance status predicts fitness, most adaptive models of dominance relationships among cercopithecine primate females predict lifetime maintenance of status. These models and alternative ones positing rank decline as a non-adaptive by-product have remained largely untested, however, because lifetime status of older adults has been virtually unknown for natural populations. In a 25-year study of adult female savannah baboons (Papio cynocephalus), in each of three social groups, rank losses were common among the 66 females that lived past median adult age. These losses were not accounted for by loss in relative rank from group growth or by loss in absolute rank from reversals in rank between members of different maternal families or between sisters. Rather, females that had mature daughters experienced loss of dominance status to these offspring, a characteristic of all but the top-ranking matriline of each group. Among proposed hypotheses for rank reversals between adults, that of kin selection based on relative reproductive value is most clearly supported by these data. In contrast, observed patterns of rank loss are not consistent with alternative models that postulate that changes during adult lifespan are a product of accumulated risk, physical decline during ageing, or coalitionary support among females within or between matrilines.}, } @article {pmid11412374, year = {2001}, author = {Van de Casteele, T and Galbusera, P and Matthysen, E}, title = {A comparison of microsatellite-based pairwise relatedness estimators.}, journal = {Molecular ecology}, volume = {10}, number = {6}, pages = {1539-1549}, doi = {10.1046/j.1365-294x.2001.01288.x}, pmid = {11412374}, issn = {0962-1083}, mesh = {Animals ; Birds/*genetics ; *Genetic Variation ; Linkage Disequilibrium ; *Microsatellite Repeats ; *Models, Genetic ; Monte Carlo Method ; }, abstract = {Studies of inbreeding depression or kin selection require knowledge of relatedness between individuals. If pedigree information is lacking, one has to rely on genotypic information to infer relatedness. In this study we investigated the performance (absolute and relative) of 10 marker-based relatedness estimators using allele frequencies at microsatellite loci obtained from natural populations of two bird species and one mammal species. Using Monte Carlo simulations we show that many factors affect the performance of estimators and that different sets of loci promote the use of different estimators: in general, there is no single best-performing estimator. The use of locus-specific weights turns out to greatly improve the performance of estimators when marker loci are used that differ strongly in allele frequency distribution. Microsatellite-based estimates are expected to explain between 25 and 79% of variation in true relatedness depending on the microsatellite dataset and on the population composition (i.e. the frequency distribution of relationship in the population). We recommend performing Monte Carlo simulations to decide which estimator to use in studies of pairwise relatedness.}, } @article {pmid11410157, year = {2001}, author = {Griffiths, SW and Armstrong, JD}, title = {The benefits of genetic diversity outweigh those of kin association in a territorial animal.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1473}, pages = {1293-1296}, doi = {10.1098/rspb.2001.1660}, pmid = {11410157}, issn = {0962-8452}, mesh = {Animals ; Environment ; Female ; *Genetic Variation ; Genetics, Population ; Male ; Models, Genetic ; Salmo salar/*genetics/growth & development/*physiology ; Scotland ; Social Behavior ; Territoriality ; }, abstract = {The theories of kin selection and heterogeneous advantage have been central to studies of altruistic behaviour and the evolution of sex over the last 35 years. Yet they predict diametrically opposite effects of genetic diversity on population density. Close relatives gain inclusive fitness advantages by preferentially associating with and behaving altruistically towards one another. However, heterogeneous advantage, which predicts competition to be highest when genetic diversity is low, suggests that benefits will be greater for individuals in groups of non-kin. Here we test how these two processes balance and affect the productivity of populations of animals in natural habitats. We report from a study of juvenile Atlantic salmon in the wild that heterogeneous advantage outweighs the benefits of kin-biased behaviour, resulting in a 1.8-fold higher population biomass and significantly better condition of individual fish.}, } @article {pmid11400215, year = {2001}, author = {Peccei, JS}, title = {A critique of the grandmother hypotheses: old and new.}, journal = {American journal of human biology : the official journal of the Human Biology Council}, volume = {13}, number = {4}, pages = {434-452}, doi = {10.1002/ajhb.1076}, pmid = {11400215}, issn = {1042-0533}, mesh = {Adaptation, Physiological/*physiology ; Animals ; *Biological Evolution ; Ecology ; Family/*psychology ; Female ; Fertility/*physiology ; Gender Identity ; *Helping Behavior ; Humans ; Longevity/*physiology ; Male ; Maternal Behavior/*physiology/*psychology ; Menopause/*physiology/*psychology ; Middle Aged ; *Models, Theoretical ; Nuclear Family/psychology ; Predictive Value of Tests ; Primates/physiology/psychology ; Reproducibility of Results ; *Selection, Genetic ; }, abstract = {The singularity of reproductive senescence in human females has led many investigators to consider menopause an adaptation permitting increased maternal investment in existing progeny. Much of the focus has been on the grandmother hypothesis-the notion that aging women gain an inclusive fitness advantage from investing in their grandchildren. This hypothesis has evolved from an explanation for menopause into an explanation for the exceptionally long postreproductive lifespan in human females. In the old grandmother hypothesis, menopause is an adaptation facilitating grandmothering; it is about stopping early in order to create a postreproductive lifespan. In the new grandmother hypothesis, grandmothering is an adaptation facilitating increased longevity, and menopause is a byproduct. This paper reviews and critically evaluates the evidence for and against both hypotheses, focusing on key predictions of each. If menopause is the result of selection for increased maternal investment, this involved mainly mothers, not grandmothers.}, } @article {pmid11380886, year = {2001}, author = {Burland, TM and Barratt, EM and Nichols, RA and Racey, PA}, title = {Mating patterns, relatedness and the basis of natal philopatry in the brown long-eared bat, Plecotus auritus.}, journal = {Molecular ecology}, volume = {10}, number = {5}, pages = {1309-1321}, doi = {10.1046/j.1365-294x.2001.01273.x}, pmid = {11380886}, issn = {0962-1083}, mesh = {Animals ; Bayes Theorem ; Chiroptera/*physiology ; Female ; Genetics, Population ; Male ; Scotland ; Sexual Behavior, Animal/*physiology ; }, abstract = {The brown long-eared bat, Plecotus auritus, is unusual among temperate zone bats in that summer maternity colonies are composed of adult males and females, with both sexes displaying natal philopatry and long-term association with a colony. Here, we describe the use of microsatellite analysis to investigate colony relatedness and mating patterns, with the aim of identifying the evolutionary determinants of social organization in P. auritus. Mean colony relatedness was found to be low (R=0.033 +/- 0.002), with pairwise estimates of R within colonies ranging from -0.4 to 0.9. The proportion of young fathered by males in their own colony was investigated using a Bayesian approach, incorporating parameters detailing the number of untyped individuals. This analysis revealed that most offspring were fathered by males originating from a different colony to their own. In addition, we determined that the number of paternal half-sibs among cohorts of young was low, inferring little or no skew in male reproductive success. The results of this study suggest that kin selection cannot account for colony stability and natal philopatry in P. auritus, which may instead be explained by advantages accrued through the use of familiar and successful roost sites, and through long-term associations with conspecifics. Moreover, because the underlying causes of male natal dispersal in mammals, such as risk of inbreeding or competition for mates, appear to be avoided via extra-colony copulation and low male reproductive skew, both P. auritus males and females are able to benefit from long-term association with the natal colony.}, } @article {pmid11375095, year = {2001}, author = {Agrawal, AF}, title = {Kin recognition and the evolution of altruism.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1471}, pages = {1099-1104}, doi = {10.1098/rspb.2001.1611}, pmid = {11375095}, issn = {0962-8452}, mesh = {*Altruism ; *Biological Evolution ; Humans ; *Models, Genetic ; }, abstract = {In 1964, Hamilton formalized the idea of kin selection to explain the evolution of altruistic behaviours. Since then, numerous examples from a diverse array of taxa have shown that seemingly altruistic actions towards close relatives are a common phenomenon. Although many species use kin recognition to direct altruistic behaviours preferentially towards relatives, this important aspect of social biology is less well understood theoretically. I extend Hamilton's classic work by defining the conditions for the evolution of kin-directed altruism when recognizers are permitted to make acceptance (type I) and rejection (type II) errors in the identification of social partners with respect to kinship. The effect of errors in recognition on the evolution of kin-directed altruism depends on whether the population initially consists of unconditional altruists or non-altruists (i.e. alternative forms of non-recognizers). Factors affecting the level of these error rates themselves, their evolution and their long-term stability are discussed.}, } @article {pmid11370964, year = {2001}, author = {Morris, DW and Lundberg, P and Ripa, J}, title = {Hamilton's rule confronts ideal free habitat selection.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1470}, pages = {921-924}, doi = {10.1098/rspb.2001.1597}, pmid = {11370964}, issn = {0962-8452}, mesh = {Animals ; *Biological Evolution ; *Environment ; *Models, Biological ; Models, Statistical ; Mole Rats ; Population Density ; Selection, Genetic ; }, abstract = {If individuals occupy habitats in a way that maximizes their fitness, if they are free to occupy the habitats they choose and if fitness declines with population density, then their abundance across habitats should follow an ideal free distribution. But, if individuals are genetically related, this simple fitness-maximization mechanism breaks down. Habitat occupation should obey Hamilton's rule (natural selection favours traits causing a loss in individual fitness as long as they result in an equal or greater gain in inclusive fitness) and depends more on inclusive fitness than it does on individual fitness. We demonstrate that the resulting inclusive-fitness distribution inflates the population density in habitats of poorer inherent quality, creating pronounced source sink dynamics. We also show that density-dependent habitat selection among relatives reinforces behaviours such as group defence and interspecific territoriality, and that it explains many anomalies in dispersal and foraging.}, } @article {pmid11348506, year = {2001}, author = {Foster, KR and Ratnieks, FL and Gyllenstrand, N and Thorén, PA}, title = {Colony kin structure and male production in Dolichovespula wasps.}, journal = {Molecular ecology}, volume = {10}, number = {4}, pages = {1003-1010}, doi = {10.1046/j.1365-294x.2001.01228.x}, pmid = {11348506}, issn = {0962-1083}, mesh = {Animals ; Female ; Genetic Variation/genetics ; Male ; Microsatellite Repeats/*genetics ; Ovary/physiology ; Reproduction ; Sexual Behavior, Animal ; Wasps/*genetics/*physiology ; }, abstract = {In annual hymenopteran societies headed by a single outbred queen, paternity (determined by queen mating frequency and sperm use) is the sole variable affecting colony kin structure and is therefore a key predictor of colony reproductive characteristics. Here we investigate paternity and male production in five species of Dolichovespula wasps. Twenty workers from each of 10 colonies of each of five species, 1000 workers in total, were analysed at three DNA microsatellite loci to estimate paternity. To examine the relationship between kin structure and reproductive behaviour, worker ovary activation was assessed by dissection and the maternal origin of adult males was assessed by DNA microsatellites. Effective paternity was low in all species (D. media 1.08, D. maculata 1.0, D. sylvestris 1.15, D. norwegica 1.08 and D. saxonica 1.35), leading to the prediction of queen-worker conflict over male production. In support of this, workers with full-size eggs in their ovaries (four out of five species) and adult males that were workers' sons (all five species) were found in queenright colonies. However, workers were only responsible for a minority of male production (D. media 7.4%, D. maculata 20.9%, D. sylvestris 9.8%, D. norwegica 2.6% and D. saxonica 34.6%) suggesting that the queen maintains considerable reproductive power over the workers. Kin structure and reproductive conflict in Dolichovespula contrast with their sister group Vespula. Dolichovespula is characterized by low paternity, worker reproduction, and queen-worker conflict and Vespula by high paternity, effective worker policing and absence of worker reproduction. The trend revealed by this comparison is as predicted by kin selection theory suggesting that colony kin structure has been pivotal in the evolution of the yellowjacket wasps.}, } @article {pmid11327153, year = {2001}, author = {Wade, MJ}, title = {Maternal effect genes and the evolution of sociality in haplo-diploid organisms.}, journal = {Evolution; international journal of organic evolution}, volume = {55}, number = {3}, pages = {453-458}, doi = {10.1554/0014-3820(2001)055[0453:megate]2.0.co;2}, pmid = {11327153}, issn = {0014-3820}, mesh = {Alleles ; Animals ; Biological Evolution ; Diploidy ; Female ; Genetics, Population ; Haploidy ; Hymenoptera/*genetics/physiology ; Male ; *Models, Genetic ; *Mothers ; Nuclear Family ; Sex Ratio ; *Social Behavior ; }, abstract = {Maternal care and female-biased sex ratios are considered by many to be essential prerequisites for the evolution of eusocial behaviors among the hymenoptera. Using population genetic models, I investigate the evolution of genes that have positive maternal effects but negative, direct effects on offspring fitness. I find that, under many conditions, such genes evolve more easily in haplo-diploids than in diplo-diploids. In fact, the conditions are less restrictive than those of kin selection theory, which postulate genes with negative direct effects but positive sib-social effects. For example, the conditions permitting the evolution of maternal effect genes are not affected if females mate multiply, whereas multiple mating reduces the efficacy of kin selection by reducing genetic relatedness within colonies. Inbreeding also differentially facilitates evolution of maternal effect genes in haplo-diploids relative to diplo-diploids, although it does not differentially affect the evolution of sib-altruism genes. Furthermore, when the direct, deleterious pleiotropic effect is restricted to sons, a maternal effect gene can evolve when the beneficial maternal effect is less than half (with inbreeding, much less) of the deleterious effect on sons. For kin selection, however, the sib-social benefits must always exceed the direct costs because genetic relatedness is always less than or equal to 1.0. The results suggest that haplo-diploidy facilitates (1) the evolution of maternal care, and (2) the evolution of maternal effect genes with antagonistic pleiotropic effects on sons. The latter effect may help explain the tendency toward female-biased sex ratios in haplo-diploids, especially those with inbreeding. I conclude that haplo-diploidy not only facilitates the evolution of sister-sister altruism by kin selection but also facilitates the evolution of maternal care and female-biased sex ratios, two prerequisites for eusociality.}, } @article {pmid11270430, year = {2001}, author = {Bourke, AF and Ratnieks, FL}, title = {Kin-selected conflict in the bumble-bee Bombus terrestris (Hymenoptera: Apidae).}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1465}, pages = {347-355}, pmid = {11270430}, issn = {0962-8452}, mesh = {Animals ; Bees/*physiology ; Female ; Male ; Oviposition/*physiology ; Sex Ratio ; }, abstract = {Kin selection theory predicts conflict in social Hymenoptera between the queen and workers over male parentage because each party is more closely related to its own male offspring. Some aspects of the reproductive biology of the bumble-bee Bombus terrestris support kin selection theory but others arguably do not. We present a novel hypothesis for how conflict over male parentage should unfold in B. terrestris colonies. We propose that workers delay laying eggs until they possess information showing that egg laying suits their kin-selected interests. In colonies where queens start to lay haploid eggs early, we hypothesize that this occurs when workers detect the presence of queen-produced male brood in the brood's larval stage. In colonies where queens start to lay haploid eggs late, we hypothesize that it occurs when workers detect a signal from the queen to female larvae to commence development as queens. Our hypothesis accounts for previously unexplained aspects of the timing of reproductive events in B. terrestris, provides ultimate explanations for the results of a recent study of mechanisms underlying queen-worker conflict and helps explain this species' characteristic bimodal (split) sex ratios. Therefore, kin selection theory potentially provides a good explanation for reproductive patterns in B. terrestris.}, } @article {pmid11251797, year = {2001}, author = {Henshaw, MT and Strassmann, JE and Queller, DC}, title = {Swarm-founding in the polistine wasps: the importance of finding many microsatellite loci in studies of adaptation.}, journal = {Molecular ecology}, volume = {10}, number = {1}, pages = {185-191}, doi = {10.1046/j.1365-294x.2001.01172.x}, pmid = {11251797}, issn = {0962-1083}, mesh = {Animals ; Behavior, Animal/*physiology ; Biological Evolution ; Genetics, Behavioral ; *Microsatellite Repeats ; Phylogeny ; *Polymorphism, Genetic ; Sequence Analysis, DNA ; Wasps/*genetics/physiology ; }, abstract = {We developed 52 microsatellite loci for the wasp, Polybioides tabidus, for the purpose of studying the evolution and inclusive fitness consequences of swarm-founding. The large number of loci is important for three reasons that may apply to many other systems. Heterozygosity was low in our target species, yet we found enough polymorphic loci for accurate kinship studies in this species. Many monomorphic loci were polymorphic in other polistine wasps, making comparative studies possible. Finally, enough loci amplified over a broad range of species to add a historical dimension. We sequenced six loci in other polistine wasps and used the flanking sequences to construct a phylogeny. Based on this phylogeny, we infer that swarm-founding has evolved independently three times in the polistine wasps.}, } @article {pmid11243923, year = {2001}, author = {Szathmáry, E}, title = {Biological information, kin selection, and evolutionary transitions.}, journal = {Theoretical population biology}, volume = {59}, number = {1}, pages = {11-14}, doi = {10.1006/tpbi.2000.1503}, pmid = {11243923}, issn = {0040-5809}, mesh = {Altruism ; *Biological Evolution ; Genetics, Behavioral/*history ; History, 20th Century ; Models, Genetic ; Molecular Biology/*history ; *Selection, Genetic ; }, } @article {pmid11222050, year = {2001}, author = {Eshel, I and Shaked, A}, title = {Partnership.}, journal = {Journal of theoretical biology}, volume = {208}, number = {4}, pages = {457-474}, doi = {10.1006/jtbi.2000.2232}, pmid = {11222050}, issn = {0022-5193}, mesh = {Aging ; Altruism ; Animals ; *Cooperative Behavior ; Family Relations ; *Models, Psychological ; Survival ; }, abstract = {Individuals are called partners when it is in their best interest to help each other, if by doing so they increase the probability of being together in the future when, for similar reasons, they will continue to help each other. Kinsmen or individuals who often face (hedonic) situations in which helping is the dominating strategy are committed to help each other. Partnership may develop among them since the loss of the other means the loss of a guaranteed helper. Thus, they may be willing to take additional risks to help each other. Partnership may occur among unrelated individuals and with no hedonic situations. Partnership creates bonds between partners which may be much stronger than those between kinsmen; an individual may take more risks for his partner than he will ever take for a kin. Partnership may evolve without the sophistication and memory required for reciprocation altruism. Although kin selection, partnership and reciprocation are likely to appear fused as the causes for altruism, we argue that it may be possible to distinguish between them in some situations. We show that as the partners get older partnership may become less important to them. We also show that like cooperation, and for analogous reasons, malice may evolve among partners so that each will be willing to take additional risks in order to eliminate the other.}, } @article {pmid11209890, year = {2001}, author = {Kokko, H and Johnstone, RA and Clutton-Brock, TH}, title = {The evolution of cooperative breeding through group augmentation.}, journal = {Proceedings. Biological sciences}, volume = {268}, number = {1463}, pages = {187-196}, pmid = {11209890}, issn = {0962-8452}, mesh = {Animals ; *Biological Evolution ; *Cooperative Behavior ; Models, Biological ; *Reproduction ; *Sexual Behavior, Animal ; }, abstract = {Some individuals (helpers) in cooperatively breeding species provide alloparental care and often suppress their own reproduction. Kin selection is clearly an important explanation for such behaviour, but a possible alternative is group augmentation where individuals survive or reproduce better in large groups and where it therefore pays to recruit new members to the group. The evolutionary stability of group augmentation is currently disputed. We model evolutionarily stable helping strategies by following the dynamics of social groups with varying degrees of subordinate help. We also distinguish between passive augmentation, where a group member benefits from the mere presence of others, and active augmentation, where their presence as such is neutral or harmful, but where helping to recruit new group members may still be beneficial if they in turn actively provide help for the current reproductives ('delayed reciprocity'). The results show that group augmentation (either passive or active) can be evolutionarily stable and explain costly helping by non-reproductive subordinates, either alone or leading to elevated help levels when acting in concert with kin selection. Group augmentation can thus potentially explain the weak relationships between relatedness and helping behaviour that are observed in some cooperatively breeding species. In some cases, the superior mutualistic performance of cooperatively behaving groups can generate an incentive to stay and help which is strong enough to make ecological constraints unnecessary for explaining the stability of cooperatively breeding groups.}, } @article {pmid11206546, year = {2001}, author = {West, SA and Murray, MG and Machado, CA and Griffin, AS and Herre, EA}, title = {Testing Hamilton's rule with competition between relatives.}, journal = {Nature}, volume = {409}, number = {6819}, pages = {510-513}, doi = {10.1038/35054057}, pmid = {11206546}, issn = {0028-0836}, mesh = {Animals ; Competitive Behavior ; Female ; Male ; Models, Biological ; Molecular Sequence Data ; Sexual Behavior, Animal ; Species Specificity ; Wasps/classification/genetics/*physiology ; }, abstract = {Hamilton's theory of kin selection suggests that individuals should show less aggression, and more altruism, towards closer kin. Recent theoretical work has, however, suggested that competition between relatives can counteract kin selection for altruism. Unfortunately, factors that tend to increase the average relatedness of interacting individuals--such as limited dispersal--also tend to increase the amount of competition between relatives. Therefore, in most natural systems, the conflicting influences of increased competition and increased relatedness are confounded, limiting attempts to test theory. Fig wasp taxa exhibit varying levels of aggression among non-dispersing males that show a range of average relatedness levels. Thus, across species, the effects of relatedness and competition between relatives can be separated. Here we report that--contrary to Hamilton's original prediction but in agreement with recent theory--the level of fighting between males shows no correlation with the estimated relatedness of interacting males, but is negatively correlated with future mating opportunities.}, } @article {pmid11162790, year = {2000}, author = {Irwin, AJ and Taylor, PD}, title = {Evolution of dispersal in a stepping-stone population with overlapping generations.}, journal = {Theoretical population biology}, volume = {58}, number = {4}, pages = {321-328}, doi = {10.1006/tpbi.2000.1490}, pmid = {11162790}, issn = {0040-5809}, mesh = {Altruism ; *Biological Evolution ; *Competitive Behavior ; Computer Simulation ; *Cooperative Behavior ; *Genetics, Population ; *Intergenerational Relations ; *Models, Genetic ; Numerical Analysis, Computer-Assisted ; Pedigree ; *Probability Theory ; *Reproduction ; }, abstract = {We use Hamilton's inclusive fitness method to calculate the evolutionarily stable dispersal rate in 1- and 2-dimensional stepping-stone populations. This extends previous results by introducing a positive probability for adults to survive into the next generation and breed again. Relatedness between nearby individuals generally decreases with increasing survival, decreasing competition with kin and favouring greater dispersal rates.}, } @article {pmid11045933, year = {2000}, author = {Kirkpatrick, RC and Plato, and Lévi-Strauss, C}, title = {The Evolution of Human Homosexual Behavior.}, journal = {Current anthropology}, volume = {999}, number = {2}, pages = {000385-000413}, pmid = {11045933}, issn = {0011-3204}, abstract = {Homosexuality presents a paradox for evolutionists who explore the adaptedness of human behavior. If adaptedness is measured by reproductive success and if homosexual behavior is nonreproductive, how has it come about? Three adaptationist hypotheses are reviewed here and compared with the anthropological literature. There is little evidence that lineages gain reproductive advantage through offspring care provided by homosexual members. Therefore, there is little support for the hypothesis that homosexuality evolved by kin selection. Parents at times control children's reproductive decisions and at times encourage children in homosexual behavior. There is therefore more support for the hypothesis of parental manipulation. Support is strongest, however, for the hypothesis that homosexual behavior comes from individual selection for reciprocal altruism. Same-sex alliances have reproductive advantages, and sexual behavior at times maintains these alliances. Nonhuman primates, including the apes, use homosexual behavior in same-sex alliances, and such alliances appear to have been key in the expanded distribution of human ancestors during the Pleistocene. Homosexual emotion and behavior are, in part, emergent qualities of the human propensity for same-sex affiliation. Adaptationist explanations do not fully explain sexual behavior in humans, however; social and historical factors also play strong roles.}, } @article {pmid11156161, year = {2000}, author = {Saito, Y}, title = {Do kin selection and intra-sexual selection operate in spider mites?.}, journal = {Experimental & applied acarology}, volume = {24}, number = {5-6}, pages = {351-363}, pmid = {11156161}, issn = {0168-8162}, mesh = {Animals ; Behavior, Animal ; Female ; Male ; Mites/*physiology ; Reproduction ; Seasons ; Sexual Behavior, Animal ; }, abstract = {Between the two subsocial spider mites, Schizotetranychus longus Saito and S. miscanthi Saito, a big difference exists in male reproductive behavior. The males of the former species have an extraordinarily mild relationship with conspecific males, whereas those of the latter species show mortal aggression against conspecific males. Field and experimental observations on the structure of mating populations showed that S. longus is under inbreeding conditions because of a lack of males in early spring, whereas S. miscanthi is under outbreeding conditions. Therefore, I hypothesized that the difference in male antagonism between the two species may reflect the difference in relatedness of males, that is, it has evolved by kin selection. The recent discovery of two clinal trends in male-male aggression in S. miscanthi provided evidence in favour of this hypothesis. Furthermore, a correlation analyses between experimentally evaluated male aggression and distribution patterns of males in the field indicated that the variation in male antagonism is actually reflected in field populations. Based on these studies, I discuss the solidity of the kin-selection hypothesis. Lastly I address how spider mites are fruitful model animals for conducting behavioral, ecological and genetic studies to understand the evolution of haplo-diploidy.}, } @article {pmid11140792, year = {2000}, author = {O'Connor, LE and Berry, JW and Weiss, J and Schweitzer, D and Sevier, M}, title = {Survivor guilt, submissive behaviour and evolutionary theory: the down-side of winning in social comparison.}, journal = {The British journal of medical psychology}, volume = {73 Pt 4}, number = {}, pages = {519-530}, doi = {10.1348/000711200160705}, pmid = {11140792}, issn = {0007-1129}, mesh = {Adaptation, Psychological ; Adolescent ; Adult ; Aged ; Biological Evolution ; Female ; *Guilt ; Humans ; Male ; Middle Aged ; Motivation ; Personality Inventory ; *Social Behavior ; Stress, Psychological ; Surveys and Questionnaires ; Survivors/*psychology ; }, abstract = {In prior research submissive behaviour has been studied in relation to social comparison. Evolutionary theory conceptualized submissive behaviour as a fear-based self-protective strategy when in a subordinate position. In this study we hypothesized that survivor guilt, the type of guilt associated with feeling better off than others, is also linked to submissive behaviour. The Interpersonal Guilt Questionnaire, the Submissive Behaviour Inventory, the Eysenck Personality Questionnaire-Revised and the Automatic Thoughts Questionnaire were administered to a sample of 199 college students. Submissive behaviour was found to be significantly correlated with survivor guilt. Introversion, used as an indirect measure of the fear of being put down, was also correlated with submissive behaviour. A principal components analysis found two components: the first was composed of high loadings of submissiveness, survivor guilt and omnipotent responsibility guilt; the second was composed of high loadings of submissiveness and introversion. This supports the hypothesis that there may be two motivational states related to submissive behaviour, the fear of harm to the self, as described in prior studies, and the fear of harm to another or guilt-based submissive behaviour. We propose that survivor guilt has been selected by evolution as a psychological mechanism supporting group living, and that it may be considered from the perspective of inclusive fitness, reciprocal altruism, and multilevel selection theory.}, } @article {pmid11127911, year = {2000}, author = {Queller, DC}, title = {Relatedness and the fraternal major transitions.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {355}, number = {1403}, pages = {1647-1655}, pmid = {11127911}, issn = {0962-8436}, mesh = {Animals ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Many of the major transitions in evolution involved the coalescence of independent lower-level units into a higher organismal level. This paper examines the role of kinship, focusing on the transitions to multicellularity in animals and to coloniality in insects. In both, kin selection based on high relatedness permitted cooperation and a reproductive division of labour. The higher relatedness of haplodiploid females to their sisters than to their offspring might not have been crucial in the origin of insect societies, and the transition to multicellularity shows that such special relationships are not required. When multicellular forms develop from a single cell, selfish conflict is minimal because each selfish mutant obtains only one generation of within-individual advantage in a chimaera. Conditionally expressed traits are particularly immune to within-individual selfishness because such mutations are rarely expressed in chimaeras. Such conditionally expressed altruism genes lead easily to the evolution of the soma, and the germ line might simply be what is left over. In most social insects, differences in relatedness ensure that there will be potential conflicts. Power asymmetries sometimes lead to such decisive settlements of conflicts that social insect colonies can be considered to be fully organismal.}, } @article {pmid11122414, year = {2000}, author = {Bever, JD and Simms, EL}, title = {Evolution of nitrogen fixation in spatially structured populations of Rhizobium.}, journal = {Heredity}, volume = {85 Pt 4}, number = {}, pages = {366-372}, doi = {10.1046/j.1365-2540.2000.00772.x}, pmid = {11122414}, issn = {0018-067X}, mesh = {*Biological Evolution ; Genotype ; Models, Genetic ; Models, Theoretical ; Nitrogen Fixation/*genetics ; Plants/genetics/microbiology ; Rhizobium/classification/*genetics/growth & development ; }, abstract = {Symbiosis between legumes and nitrogen-fixing bacteria is thought to bring mutual benefit to each participant. However, it is not known how rhizobia benefit from nodulation of legume hosts because they fix nitrogen only after differentiating into bacteroids, terminally differentiated cells that cannot reproduce. Because free-living rhizobia can reproduce, and may benefit from the increase of plant root exudates stimulated by nodulation, evolution of symbiotic nitrogen fixation may depend upon kin selection. However, unrelated nonmutualists may also benefit from increased plant exudates and nitrogen-fixing populations are therefore vulnerable to invasion by nonfixing, saprophytic Rhizobium. The access of nonfixing Rhizobium to the plant exudates associated with nodules depends upon the spatial structure of the Rhizobium populations within the soil. We investigate the influence of spatial structure on the evolution of N-fixation within a Rhizobium population using a mathematical model. Our model demonstrates that spatial structure is necessary for the evolution of N-fixation and that N-fixation is more likely to evolve with increasing degrees of spatial structure. In fact, we identify three dynamic outcomes that depend upon the relative strength of the costs of N-fixation relative to the degree of spatial structure and benefits resulting from nodulations. If the costs are relatively high, N-fixation will not evolve; if the costs are relatively low, N-fixing genes will fix in the population, but at intermediate conditions, a stable mixture of N-fixing bacteria and nonfixing bacteria will be maintained. The conditions for coexistence of N-fixing bacteria and nonfixing bacteria expand under a saturating relationship between nodule numbers and N-fixing genotype frequency.}, } @article {pmid11099040, year = {2000}, author = {Shorey, L and Piertney, S and Stone, J and Höglund, J}, title = {Fine-scale genetic structuring on Manacus manacus leks.}, journal = {Nature}, volume = {408}, number = {6810}, pages = {352-353}, doi = {10.1038/35042562}, pmid = {11099040}, issn = {0028-0836}, mesh = {Alleles ; Animals ; Biological Evolution ; Female ; Gene Frequency ; Male ; Microsatellite Repeats ; *Sexual Behavior, Animal ; Songbirds/*genetics/physiology ; }, abstract = {Leks have traditionally been considered as arenas where males compete to attract females and secure matings. Thus, direct fitness benefits mediated through competition between males to fertilize females have been considered to be the primary force driving the evolution of lekking behaviour. Inclusive fitness benefits mediated through kin selection may also be involved in lek formation and evolution, but to date this theory has been largely ignored. According to kin-selection theory, both reproducing and non-reproducing males may gain indirect inclusive fitness benefits. If females are attracted to larger leks, non-reproducing males add attractiveness to a lek, and therefore, in a genetically structured population, boost the reproductive success of kin. Theory predicts that the attractiveness of leks is plastic, and that males establish themselves on a lek in which the top male, in terms of reproductive success, is a close relative. Here we show that in white-bearded manakins (Manacus manacus), for which larger leks are more attractive to females and so secure the maximum number of matings, there is extraordinary fine-scale genetic structure, with leks being composed of clusters of related kin. We propose that males establish themselves where they find relatives to such an extent that they form groups within leks, and that such behaviour is consistent with kin-selection theory to maximize reproductive success of the group.}, } @article {pmid11087847, year = {2000}, author = {Lyon, BE and Eadie, JM}, title = {Family matters: kin selection and the evolution of conspecific brood parasitism.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {97}, number = {24}, pages = {12942-12944}, pmid = {11087847}, issn = {0027-8424}, mesh = {Animals ; Birds/classification/*genetics/*parasitology ; Ducks/classification/parasitology ; Female ; Host-Parasite Interactions ; *Maternal Behavior ; Phylogeny ; *Social Behavior ; }, } @article {pmid11050150, year = {2000}, author = {Andersson, M and Ahlund, M}, title = {Host-parasite relatedness shown by protein fingerprinting in a brood parasitic bird.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {97}, number = {24}, pages = {13188-13193}, pmid = {11050150}, issn = {0027-8424}, mesh = {Animals ; DNA Fingerprinting ; Ducks/genetics/*physiology ; Female ; Host-Parasite Interactions ; *Maternal Behavior ; Oviposition ; *Social Behavior ; }, abstract = {Brood parasitism as an alternative female breeding tactic is particularly common in ducks, where hosts often receive eggs laid by parasitic females of the same species and raise their offspring. Herein, we test several aspects of a kin selection explanation for this phenomenon in goldeneye ducks (Bucephala clangula) by using techniques of egg albumen sampling and statistical bandsharing analysis based on resampling. We find that host and primary parasite are indeed often related, with mean r = 0.13, about as high as between first cousins. Relatedness to the host is higher in nests where a parasite lays several eggs than in those where she lays only one. Returning young females parasitize their birth nestmates (social mothers or sisters, which are usually also their genetic mothers and sisters) more often than expected by chance. Such adult relatives are also observed together in the field more often than expected and for longer periods than other females. Relatedness and kin discrimination, which can be achieved by recognition of birth nestmates, therefore play a role in these tactics and probably influence their success.}, } @article {pmid11045928, year = {2000}, author = {Kirkpatrick, RC and Plato, and Lévi-Strauss, C}, title = {The Evolution of Human Homosexual Behavior.}, journal = {Current anthropology}, volume = {999}, number = {1}, pages = {000385-000413}, pmid = {11045928}, issn = {0011-3204}, abstract = {Homosexuality presents a paradox for evolutionists who explore the adaptedness of human behavior. If adaptedness is measured by reproductive success and if homosexual behavior is nonreproductive, how has it come about? Three adaptationist hypotheses are reviewed here and compared with the anthropological literature. There is little evidence that lineages gain reproductive advantage through offspring care provided by homosexual members. Therefore, there is little support for the hypothesis that homosexuality evolved by kin selection. Parents at times control children's reproductive decisions and at times encourage children in homosexual behavior. There is therefore more support for the hypothesis of parental manipulation. Support is strongest, however, for the hypothesis that homosexual behavior comes from individual selection for reciprocal altruism. Same-sex alliances have reproductive advantages, and sexual behavior at times maintains these alliances. Nonhuman primates, including the apes, use homosexual behavior in same-sex alliances, and such alliances appear to have been key in the expanded distribution of human ancestors during the Pleistocene. Homosexual emotion and behavior are, in part, emergent qualities of the human propensity for same-sex affiliation. Adaptationist explanations do not fully explain sexual behavior in humans, however; social and historical factors also play strong roles.}, } @article {pmid11042105, year = {2000}, author = {Ronce, O and Gandon, S and Rousset, F}, title = {Kin selection and natal dispersal in an age-structured population.}, journal = {Theoretical population biology}, volume = {58}, number = {2}, pages = {143-159}, doi = {10.1006/tpbi.2000.1476}, pmid = {11042105}, issn = {0040-5809}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Female ; *Genetics, Population ; Life Cycle Stages ; Maternal Behavior ; Models, Theoretical ; Population Dynamics ; }, abstract = {We examine the effect of iteroparity on the evolution of dispersal for a species living in a stable but fragmented habitat. We use a kin selection model that incorporates the effects of demographic stochasticity on the local age structure and age-specific genetic identities. We consider two cases: when the juvenile dispersal rate is allowed to change with maternal age and when it is not. In the latter case, we find that the unconditional evolutionarily stable dispersal rate increases when the adult survival rate increases. Two antagonistic forces act upon the evolution of age-specific dispersal rates. First, when the local age structure varies between patches of habitat, the intensity of competition between adults and juveniles in the natal patch is, on average, lower for offspring born to older senescent mothers. This selects for decreasing dispersal with maternal age. Second, offspring born to older parents are on average more related to other juveniles in the same patch and they experience a higher intensity of kin competition, which selects for increasing dispersal with maternal age. We show that the evolutionary outcome results from a balance between these two opposing forces, which depends on the amount of variance in age structure among sub-populations.}, } @article {pmid11008699, year = {2000}, author = {Chao, L and Hanley, KA and Burch, CL and Dahlberg, C and Turner, PE}, title = {Kin selection and parasite evolution: higher and lower virulence with hard and soft selection.}, journal = {The Quarterly review of biology}, volume = {75}, number = {3}, pages = {261-275}, doi = {10.1086/393499}, pmid = {11008699}, issn = {0033-5770}, mesh = {Adaptation, Physiological ; Animals ; Bacteria/genetics/pathogenicity ; *Biological Evolution ; Host-Parasite Interactions ; Humans ; Models, Genetic ; Parasites/genetics/pathogenicity/*physiology ; *Selection, Genetic ; Virulence ; Viruses/genetics/pathogenicity ; }, abstract = {Conventional models predict that low genetic relatedness among parasites that coinfect the same host leads to the evolution of high parasite virulence. Such models assume adaptive responses to hard selection only. We show that if soft selection is allowed to operate, low relatedness leads instead to the evolution of low virulence. With both hard and soft selection, low relatedness increases the conflict among coinfecting parasites. Although parasites can only respond to hard selection by evolving higher virulence and overexploiting their host, they can respond to soft selection by evolving other adaptations, such as interference, that prevent overexploitation. Because interference can entail a cost, the host may actually be underexploited, and virulence will decrease as a result of soft selection. Our analysis also shows that responses to soft selection can have a much stronger effect than responses to hard selection. After hard selection has raised virulence to a level that is an evolutionarily stable strategy, the population, as expected, cannot be invaded by more virulent phenotypes that respond only to hard selection. The population remains susceptible to invasion by a less virulent phenotype that responds to soft selection, however. Thus, hard and soft selection are not just alternatives. Rather, soft selection is expected to prevail and often thwart the evolution of virulence in parasites. We review evidence from several parasite systems and find support for soft selection. Most of the examples involve interference mechanisms that indirectly prevent the evolution of higher virulence. We recognize that hard selection for virulence is more difficult to document, but we take our results to suggest that a kin selection model with soft selection may have general applicability.}, } @article {pmid11005283, year = {2000}, author = {Taylor, PD and Irwin, AJ}, title = {Overlapping generations can promote altruistic behavior.}, journal = {Evolution; international journal of organic evolution}, volume = {54}, number = {4}, pages = {1135-1141}, doi = {10.1111/j.0014-3820.2000.tb00549.x}, pmid = {11005283}, issn = {0014-3820}, mesh = {*Altruism ; *Biological Evolution ; Computer Simulation ; Fertility ; Game Theory ; Humans ; Models, Biological ; Probability ; *Social Behavior ; Survival ; }, abstract = {We use an inclusive fitness model to study the evolution of altruism in a patch-structured population in which there is positive probability of breeder survival from one generation to the next. We find first that breeder survival promotes altruism and second that there is a marked difference between benefits of fecundity and benefits of survival. Under the first altruism is more strongly favored, and under the second altruism is less strongly favored than in a randomly mixing population.}, } @article {pmid11003848, year = {2000}, author = {Shimizu, KK and Okada, K}, title = {Attractive and repulsive interactions between female and male gametophytes in Arabidopsis pollen tube guidance.}, journal = {Development (Cambridge, England)}, volume = {127}, number = {20}, pages = {4511-4518}, doi = {10.1242/dev.127.20.4511}, pmid = {11003848}, issn = {0950-1991}, mesh = {Arabidopsis/genetics ; Brassicaceae/genetics ; Cell Communication ; Crosses, Genetic ; Genes, Plant ; Haploidy ; Models, Biological ; Mutation ; Phenotype ; Plant Shoots/*growth & development ; Pollen/*growth & development ; Reproduction/genetics ; Species Specificity ; }, abstract = {Sexual reproduction in plants, unlike that of animals, requires the action of multicellular haploid gametophytes. The male gametophyte (pollen tube) is guided to a female gametophyte through diploid sporophytic cells in the pistil. While interactions between the pollen tube and diploid cells have been described, little is known about the intercellular recognition systems between the pollen tube and the female gametophyte. In particular, the mechanisms that enable only one pollen tube to interact with each female gametophyte, thereby preventing polysperm, are not understood. We isolated female gametophyte mutants named magatama (maa) from Arabidopsis thaliana by screening for siliques containing half the normal number of mature seeds. In maa1 and maa3 mutants, in which the development of the female gametophyte was delayed, pollen tube guidance was affected. Pollen tubes were directed to mutant female gametophytes, but they lost their way just before entering the micropyle and elongated in random directions. Moreover, the mutant female gametophytes attracted two pollen tubes at a high frequency. To explain the interaction between gametophytes, we propose a monogamy model in which a female gametophyte emits two attractants and prevents polyspermy. This prevention process by the female gametophyte could increase a plant's inclusive fitness by facilitating the fertilization of sibling female gametophytes. In addition, repulsion between pollen tubes might help prevent polyspermy. The reproductive isolations observed in interspecific crosses in Brassicaceae are also consistent with the monogamy model.}, } @article {pmid10972773, year = {2000}, author = {Painter, JN and Crozier, RH and Poiani, A and Robertson, RJ and Clarke, MF}, title = {Complex social organization reflects genetic structure and relatedness in the cooperatively breeding bell miner, Manorina melanophrys.}, journal = {Molecular ecology}, volume = {9}, number = {9}, pages = {1339-1347}, doi = {10.1046/j.1365-294x.2000.01012.x}, pmid = {10972773}, issn = {0962-1083}, mesh = {Animals ; Ecosystem ; Female ; Genetics, Population ; Male ; Microsatellite Repeats ; Reproduction ; Sexual Behavior, Animal ; Social Behavior ; Songbirds/*genetics/physiology ; }, abstract = {The cooperatively breeding bell miner, Manorina melanophrys, differs from most other cooperative breeding species in the complexity of its social system, where discrete social organization occurs on at least three levels. Microsatellite markers were used to investigate the degree of genetic structure underlying the social organization of M. melanophrys by comparing colonies, coteries and nest contingents. The genetic data confirmed behavioural observations of M. melanophrys living in male kin-based groups between which females disperse short distances to breed. Estimates of FST revealed restricted gene flow between eight colonies located within 30 km that was significantly associated with geographical distance when the two most distant colonies were included. Within a high density colony significant differences were found between coteries; analysis of the degree of relatedness between coterie members showed that this is due to related individuals associating preferentially with each other. Similarly, the contingent of individuals attending a nest were generally close relatives of the young they were aiding, supporting models invoking kin selection as the selective agency mediating helping.}, } @article {pmid10937206, year = {2000}, author = {Pen, I}, title = {Reproductive effort in viscous populations.}, journal = {Evolution; international journal of organic evolution}, volume = {54}, number = {1}, pages = {293-297}, doi = {10.1111/j.0014-3820.2000.tb00030.x}, pmid = {10937206}, issn = {0014-3820}, mesh = {Animals ; Biological Evolution ; Female ; Fertility/genetics ; Genetics, Population ; Male ; Models, Genetic ; Reproduction/*genetics ; *Selection, Genetic ; }, abstract = {Here I study a kin selection model of reproductive effort, the allocation of resources to fecundity versus survival, in a patch-structured population. Breeding females remain in the same patch for life. Offspring have costly, partial long-distance dispersal and compete for breeding sites, which become vacant upon the death of previous occupants. The main result is that the evolutionarily stable reproductive effort decreases as offspring dispersal rate increases. The result can be understood as follows: In a well-mixed population with global competition, neither adults nor juveniles compete with relatives, but in a patch-structured population with dispersal restricted to the juvenile phase, juveniles experience relatively less competition with relatives than adults, thus making juveniles relatively more valuable. Because this asymmetry between adults and juveniles decreases with the dispersal rate, so does the evolutionarily stable level of allocation to fecundity.}, } @article {pmid10900187, year = {2000}, author = {Day, T and Taylor, PD}, title = {A generalization of Pontryagin's maximum principle for dynamic evolutionary games among relatives.}, journal = {Theoretical population biology}, volume = {57}, number = {4}, pages = {339-356}, doi = {10.1006/tpbi.2000.1459}, pmid = {10900187}, issn = {0040-5809}, mesh = {*Biological Evolution ; Ecosystem ; *Family ; *Models, Genetic ; Plants ; Population Dynamics ; Social Behavior ; }, abstract = {We present two theorems that generalize Pontryagin's maximum principle to the setting of dynamic evolutionary games between genetically related individuals. The two theorems correspond to two types of interactions among individuals: patch-structured populations in which individuals locally "play the field" and pairwise interactions. These generalizations can be used in the same way that Pontryagin's maximum principle is used and they are valid for diploid organisms under a single locus, diallelic genetic model. These generalizations involve an interesting, dynamic version of Hamilton's Rule from inclusive fitness theory. We illustrate how these theoretical results can be applied by modeling the evolution of lifetime resource allocation to growth and reproduction in an annual plant when there is competition for resources among related individuals.}, } @article {pmid10867735, year = {2000}, author = {Bowles, JT}, title = {Sex, kings and serial killers and other group-selected human traits.}, journal = {Medical hypotheses}, volume = {54}, number = {6}, pages = {864-894}, doi = {10.1054/mehy.1999.0951}, pmid = {10867735}, issn = {0306-9877}, mesh = {Aging/metabolism ; Animals ; Body Constitution ; *Dangerous Behavior ; Female ; Fossils ; Genetic Linkage ; Homicide ; Hormones/physiology ; Humans ; Litter Size ; Male ; Mutation ; Pregnancy ; *Selection, Genetic ; }, abstract = {UNLABELLED: (Note: This unorthodox paper contains the first argument for heart disease being a programmed age change and promoted by the dramatic, post age-40 increases in the hormones FSH and hCG seen in some individuals.) A recent issue of Science suggests that the evolutionary purpose of sex is unknown.

PARADOX: Surviving to adulthood implies a valuable gene combination which is destroyed by sexual recombination. This should be detrimental to offspring. PROPOSED: Sex is group-selected in prey to allow coalescence of beneficial, and disposal of detrimental, mutations in single individuals enabling rapid adaptation to novel predation. Group selection is a universal force driven by local inter-species (not intra-species) competition. Aging, metabolism, litter size, and fixed body size are directly linked. Sexual recombination and chromosomes destroy gene linkage and exist because mutations are usually detrimental, rarely positive, and occur in linked groups. In unevolving environments, sex is selected against and asexuality emerges. Periodic evolution of novel predators, like man, can explain the 'punctuated equilibria' fossil record. Genes inhibited by methylation or chromatin condensation, expressed at older ages in predation-minimized environments, allow for group selection. Stress increases mutation rates and beneficial mutation likelihood. Females select bigger, brighter, louder, or stronger males that can survive predator attention. Size approximates age and thus predator encounters; male traits represent predation-survival potential. Human male traits include, balding, acne, beard-length, wrinkling, graying, nose/ear growth. Progeria accelerates development of most male traits. Domination of groups by single males allows rapid predation-defense evolution: adolescent males are expelled, brave the wild, and expel another group's male to mate. If expelled and dominant males are culled by predation, males reaching puberty first will reproduce. Hormonal acceleration of puberty accelerates aging/population turnover, induces smaller bodies, larger litters. With a fixed group biomass, more, smaller, stressed individuals with faster aging/turnover, increase beneficial mutation likelihood. 'Kin selection', where dominant families are supported by celibate relatives, allow the best group genes to survive famine. Dominant families gorge while others starve. Equal food sharing results in group extinction leading to group-evolved human traits of social hierarchy, greed, king/queen/God worship. Menstrual hormone cycling parallels aging. FSH and DHT promote ovarian, hair, acne, dental, and arterial follicle development causing ovulation, hair growth, pimples, dental caries, and atherosclerotic soft plaques. Soft plaques contain macrophages and LDL plug; upper plaque layers thin and rupture, releasing LDL plug, causing thrombosis. FSH withdrawal or LH/hCG increases trigger ovulation and thrombosis. Artery narrowing atherosclerotic hard plaques are stress-induced through cortisol-promoted necrotic calcification. LH/hCG-induced apoptosis promotes ovulation and aging-related somatic atrophy. Long-term estradiol stimulates, while progesterone suppresses, gonadotropin levels. Estradiol protects by inhibiting gonadotropin bioactivity and has extracellular antioxidant, but intranuclear free radical, effects. Female X-linked gene mosaicism conserves evolved aging systems. Maternal age factors for chromosomal trisomy suggest menopause prevents human parthenogenesis. Homosexuality and serial killing inhibit genetic contribution by individuals evolutionarily perceived as stressed. Smoking during pregnancy may induce homosexual offspring. Nitric oxide, a free radical, stimulates cGMP, but not cAMP. cGMP likely first evolved as an antioxidant defense to free radicals. Human aging syndromes might reflect human evolution progression. AS#4 affects tissues evolved from plant ancestors, AS#5a - from predators, AS#5b-immune system, and AS#6-sex tissues. (ABSTRACT TRUNCA}, } @article {pmid10866197, year = {2000}, author = {Queller, DC and Zacchi, F and Cervo, R and Turillazzi, S and Henshaw, MT and Santorelli, LA and Strassmann, JE}, title = {Unrelated helpers in a social insect.}, journal = {Nature}, volume = {405}, number = {6788}, pages = {784-787}, doi = {10.1038/35015552}, pmid = {10866197}, issn = {0028-0836}, mesh = {Animals ; Female ; *Helping Behavior ; Male ; Wasps/*physiology ; }, abstract = {High-resolution genetic markers have revolutionized our understanding of vertebrate mating systems, but have so far yielded few comparable surprises about kinship in social insects. Here we use microsatellite markers to reveal an unexpected and unique social system in what is probably the best-studied social wasp, Polistes dominulus. Social insect colonies are nearly always composed of close relatives; therefore, non-reproductive helping behaviour can be favoured by kin selection, because the helpers aid reproductives who share their genes. In P. dominulus, however, 35% of foundress nestmates are unrelated and gain no such advantage. The P. dominulus system is unlike all other cases of unrelated social insects, because one individual has nearly complete reproductive dominance over subordinates who could have chosen other reproductive options. The only significant advantage that subordinates obtain is a chance at later reproduction, particularly if the queen dies. Thus, P. dominulus societies are functionally unlike other social insects, but similar to certain vertebrate societies, in which the unrelated helpers gain through inheritance of a territory or a mate.}, } @article {pmid10863362, year = {2000}, author = {Provorov, NA}, title = {[The population genetics of nodule bacteria].}, journal = {Zhurnal obshchei biologii}, volume = {61}, number = {3}, pages = {229-257}, pmid = {10863362}, issn = {0044-4596}, mesh = {Altruism ; Bacteria/*genetics ; Biological Evolution ; Genetics, Population ; Plant Roots/*microbiology ; Polymorphism, Genetic/genetics ; Species Specificity ; }, abstract = {The data are reviewed on the population structure and evolutionary dynamics of the nodule bacteria (rhizobia) which are among the most intensively studied microorganisms. High level of the population polymorphism was demonstrated for the rhizobia populations using the enzyme electrophoresis (MLEE profiles). The average value of Nei's coefficient of heterogeneity (H = 1 - sigma pi2 [n/(n - 1)]) were: 0.590 for rhizobia (Rhizobium, Bradyrhizobium), 0.368 for enterobacteria (Escherichia, Salmonella, Shigella) and 0.452 for pathogenic bacteria (Bordetella, Borrelia, Erysipelothrix, Haemophilus, Helicobacter, Listeria, Mycobacterium, Neisseria, Staphylococcus) populations. In spite of being devoid of the effective systems for the gene conjugative transfer, many rhizobia populations possess an essentially panmictic structure. However, the enterobacteria populations in which the gene transfer may be facilitated due to the conjugative F- and R-factors, usually display the clonal population structure. The legume host plant is proved to be a key factor that determines the high levels of polymorphism and of panmixis as well as high evolutionary rates of the symbiotic bacteria populations. The host may ensure: a) an increase in mutation and gene transfer frequencies; b) stimulation of the competitive (selective) processes in both symbiotic and free-living rhizobia populations. A "cyclic" model of the rhizobia microevolution is presented which allows to assess the inputs the interstrain competition for the saprophytic growth and for the host nodulation into evolution of a plant-associated rhizobia population. The nodulation competitiveness in the rhizobia populations is responsible for the frequency-dependent selection of the rare genotypes which may arise in the soil bacterial communities as a result of the transfer of symbiotic (sym) genes from virulent rhizobia strains to either avirulent rhizobia or to the other (saprophytic, phytopathogenic) bacteria. Therefore, the nodulation competitiveness may ensure: a) panmictic structure of the natural rhizobia populations; b) high taxonomic diversity of rhizobia which was apparently caused by a broad sym gene expansion in the soil bacterial communities. The kin selection models are presented which explain evolution of the "altruistic" (essential for the host plant, but not for the bacteria themselves) symbiotic traits (e.g., the ability for symbiotic nitrogen fixation and for differentiation into non-viable bacteroids) in the rhizobia populations. These models are based on preferential multiplication of the nitrogen-fixing clones either in planta (due to an elevated supply of the nitrogen-fixing nodules with photosynthates) or ex planta (due to a release of the rhizopines from the nitrogen-fixing nodules). Speaking generally, interactions with the host plants provide a range of mechanisms increasing a genetic heterogeneity and an evolutionary potential in the associated rhizobia populations.}, } @article {pmid10834287, year = {2000}, author = {Crognier, E}, title = {Biological adaptation and social behaviour.}, journal = {Annals of human biology}, volume = {27}, number = {3}, pages = {221-237}, doi = {10.1080/030144600282118}, pmid = {10834287}, issn = {0301-4460}, mesh = {*Adaptation, Physiological ; Animals ; Biological Evolution ; Culture ; Humans ; *Selection, Genetic ; *Social Behavior ; }, abstract = {In 1930, both Fisher and Wright identified Darwin's initial concept of adaptive evolution in the light of the genetical theory with intergenerational variation in allelic frequencies brought about by the action of natural selection through differential reproduction. They emphasized that selection only works at the level of the individual and that its only consequence is to increase fitness. One genetical evolution not easy to explain on these bases was that of social behaviour because any altruistic gene disadvantageous for its carriers in an antisocial environment would have been opposed by selection. In the 1950s, ethologists focusing on what appeared to be evolved collective behaviours, hypothesized that selection could operate at group level. Though the controversy between group selectionists and evolutionary geneticists ended by the rejection of the evolutionary role of group selection, it has remained a subject of investigation until now. Kin selection, proposed by Hamilton, offered a solution to the problem of the evolution of altruism and gave the impetus to the trend of adaptive explanations of basic behaviours, which was to become the core of human sociobiology. The intrusion of behaviour into the process of adaptive evolution was an invitation to investigate culture as an evolutive process. The first sociobiological interpretations of culture as a derivative of genetic processes were followed by other ideas in which culture, though channelled by evolved predispositions, was essentially free from biological determinism. It is concluded that as we have come to better understand human adaptation, its complexities have been further revealed, a development already implicit in Darwin's notion.}, } @article {pmid10811892, year = {2000}, author = {Tsutsui, ND and Suarez, AV and Holway, DA and Case, TJ}, title = {Reduced genetic variation and the success of an invasive species.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {97}, number = {11}, pages = {5948-5953}, pmid = {10811892}, issn = {0027-8424}, support = {P30 CA023100/CA/NCI NIH HHS/United States ; 5P0CA23100-16/CA/NCI NIH HHS/United States ; }, mesh = {Aggression ; Alleles ; Animals ; Ants/*genetics/physiology ; Argentina ; Bermuda ; *Gene Frequency ; *Genetic Variation ; Genetics, Population ; Microsatellite Repeats ; Molecular Sequence Data ; Social Behavior ; United States ; }, abstract = {Despite the severe ecological and economic damage caused by introduced species, factors that allow invaders to become successful often remain elusive. Of invasive taxa, ants are among the most widespread and harmful. Highly invasive ants are often unicolonial, forming supercolonies in which workers and queens mix freely among physically separate nests. By reducing costs associated with territoriality, unicolonial species can attain high worker densities, allowing them to achieve interspecific dominance. Here we examine the behavior and population genetics of the invasive Argentine ant (Linepithema humile) in its native and introduced ranges, and we provide a mechanism to explain its success as an invader. Using microsatellite markers, we show that a population bottleneck has reduced the genetic diversity of introduced populations. This loss is associated with reduced intraspecific aggression among spatially separate nests, and leads to the formation of interspecifically dominant supercolonies. In contrast, native populations are more genetically variable and exhibit pronounced intraspecific aggression. Although reductions in genetic diversity are generally considered detrimental, these findings provide an example of how a genetic bottleneck can lead to widespread ecological success. In addition, these results provide insights into the origin and evolution of unicoloniality, which is often considered a challenge to kin selection theory.}, } @article {pmid10792944, year = {2000}, author = {Mitani, JC and Merriwether, DA and Zhang, C}, title = {Male affiliation, cooperation and kinship in wild chimpanzees.}, journal = {Animal behaviour}, volume = {59}, number = {4}, pages = {885-893}, doi = {10.1006/anbe.1999.1389}, pmid = {10792944}, issn = {0003-3472}, abstract = {Long-term field research has revealed that male chimpanzees, Pan troglodytes, affiliate and cooperate in several contexts. Assuming close genetic relationship among males, affiliative and cooperative behaviour have been hypothesized to evolve through the indirect effects of kin selection. We tested the hypothesis that matrilineal genetic relatedness affects patterns of male social affiliation and cooperation in an unusually large community of chimpanzees at the Ngogo study site, Kibale National Park, Uganda. Field observations indicated that six behavioural measures of affiliation and cooperation among 23 adult males were significantly correlated with each other. Sequences of the first hypervariable portion of the mtDNA genome revealed that three pairs of males and one quintet shared mtDNA haplotypes. Matrix permutation tests using behavioural and genetic data showed that males that affiliated and cooperated with each other were not closely related through the maternal line. These findings add to a growing body of empirical evidence that suggest kinship plays an ancillary role in structuring patterns of wild chimpanzee behaviour within social groups. Copyright 2000 The Association for the Study of Animal Behaviour.}, } @article {pmid10792923, year = {2000}, author = {Hayes, LD}, title = {To nest communally or not to nest communally: a review of rodent communal nesting and nursing.}, journal = {Animal behaviour}, volume = {59}, number = {4}, pages = {677-688}, doi = {10.1006/anbe.1999.1390}, pmid = {10792923}, issn = {0003-3472}, abstract = {Communal nesting, the sharing of parental responsibilities between multiple individuals in a nest, is common in many rodents. Upon first glance, this behaviour seems to be selectively disadvantageous. Communal care not only involves energetic costs, but may also be subject to cheating behaviour. Despite abundant literature, many questions remain regarding advantages gained by females that form nesting groups. I discuss the communal nesting of eusocial, singular and plural breeding rodents. I first clarify the distinction between communal nesting and thermoregulatory huddling. I then review two major groups of hypotheses ('ecological constraints' and 'benefits of philopatry') that are used to explain the occurrence of communal nesting in rodents. Most likely, these hypotheses are not mutually exclusive. Regardless of the main selective pressure(s) acting on communal nesting, the indirect components of inclusive fitness that result from nest sharing most likely influence the formation and maintenance of communal nests. Communal nesting and nursing (the sharing of milk with nonoffspring) are under different selective regimes and thus, must be evaluated separately. I review adaptive and nonadaptive hypotheses for rodent communal nursing. I argue that communal nursing may not be adaptive as mothers may be forced to share milk with nonoffspring in large communal nests (i.e. communal nursing may be a cost associated with communal nesting). In conclusion, I propose directions for future study that may improve our understanding of communal nesting and nursing in the wild. Copyright 2000 The Association for the Study of Animal Behaviour.}, } @article {pmid10785348, year = {2000}, author = {Jankowiak, W and Diderich, M}, title = {Sibling solidarity in a polygamous community in the USA. unpacking inclusive fitness.}, journal = {Evolution and human behavior : official journal of the Human Behavior and Evolution Society}, volume = {21}, number = {2}, pages = {125-139}, doi = {10.1016/s1090-5138(00)00027-1}, pmid = {10785348}, issn = {1090-5138}, abstract = {This pilot study explores the degree of solidarity felt between full and half siblings who are raised in a Mormon Fundamentalist polygamous community. The community under study is unique in that, at the level of official culture, it actively promotes full and half sibling solidarity through an ethos that strives to downplay genetic differences in favor of a harmonious family living together in one household. This community is an ideal cultural setting in which to examine the suitability of inclusive fitness theory for understanding the factors that promote family cohesion, sibling solidarity, and rivalry. Our main question becomes: is the degree of sibling solidarity a manifestation of genetic closeness or a natural byproduct of emotional closeness that arises from being raised together? We found evidence for more solidarity between full siblings than between half siblings. Our data suggest that, despite the force of religious ideals, and notwithstanding the continued close physical proximity of half siblings in the polygamous family, there is a pronounced clustering of feeling and affection in the polygamous family that is consistent with inclusive fitness theory.}, } @article {pmid10768881, year = {2000}, author = {Kirkpatrick, RC and Plato, and Lévi-Strauss, C}, title = {The Evolution of Human Homosexual Behavior.}, journal = {Current anthropology}, volume = {41}, number = {3}, pages = {385-413}, pmid = {10768881}, issn = {0011-3204}, abstract = {Homosexuality presents a paradox for evolutionists who explore the adaptedness of human behavior. If adaptedness is measured by reproductive success and if homosexual behavior is nonreproductive, how has it come about? Three adaptationist hypotheses are reviewed here and compared with the anthropological literature. There is little evidence that lineages gain reproductive advantage through offspring care provided by homosexual members. Therefore, there is little support for the hypothesis that homosexuality evolved by kin selection. Parents at times control children's reproductive decisions and at times encourage children in homosexual behavior. There is therefore more support for the hypothesis of parental manipulation. Support is strongest, however, for the hypothesis that homosexual behavior comes from individual selection for reciprocal altruism. Same-sex alliances have reproductive advantages, and sexual behavior at times maintains these alliances. Nonhuman primates, including the apes, use homosexual behavior in same-sex alliances, and such alliances appear to have been key in the expanded distribution of human ancestors during the Pleistocene. Homosexual emotion and behavior are, in part, emergent qualities of the human propensity for same-sex affiliation. Adaptationist explanations do not fully explain sexual behavior in humans, however; social and historical factors also play strong roles.}, } @article {pmid10718732, year = {2000}, author = {Reeve, HK}, title = {A Transactional Theory of Within-Group Conflict.}, journal = {The American naturalist}, volume = {155}, number = {3}, pages = {365-382}, doi = {10.1086/303322}, pmid = {10718732}, issn = {1537-5323}, abstract = {Transactional models of social evolution emphasize that dominant members of the society can be favored to donate parcels of reproduction to subordinate members in return for cooperation. I construct a formal theory of intragroup conflict within the framework of transactional models by determining the maximum extent to which colony members can be selfish without destabilizing the group. The difference between the maximum value of the subordinate's fraction of group reproduction that the dominant can tolerate before ejecting the subordinate and the minimum value required by the subordinate to stay and cooperate peacefully in the group defines the "window of selfishness," which in turn predicts the frequency of within-group conflict. The window of selfishness tends to increase with increasing group reproductive output, increasingly harsh ecological constraints on solitary breeding, and, counterintuitively, increasing relatedness between subordinate and dominant. Increasing fighting ability of the subordinate can either widen or narrow the window of selfishness, the latter being most likely when ecological constraints on group living are strong. Although increasing relatedness is predicted to increase the rate of within-group aggression, the mean intensity of an aggressive act should decline, as predicted by the general theory of honest signaling between relatives and the tug-of-war models of within-group selfishness. In the bidding game, in which multiple dominants bid for the services of a subordinate, the window of selfishness is predicted to have zero width. A zero-width window of selfishness and low conflict also are predicted for saturated N-person groups, that is, groups whose total output is a concave function of group size and in which the dominant is not favored to admit additional subordinates. The model's predictions are compared to empirical evidence and to predictions of alternative models of intragroup aggression, including the value-aggression model and the pure tug-of-war model.}, } @article {pmid10714885, year = {2000}, author = {Clutton-Brock, TH and Brotherton, PN and O'Riain, MJ and Griffin, AS and Gaynor, D and Sharpe, L and Kansky, R and Manser, MB and McIlrath, GM}, title = {Individual contributions to babysitting in a cooperative mongoose, Suricata suricatta.}, journal = {Proceedings. Biological sciences}, volume = {267}, number = {1440}, pages = {301-305}, pmid = {10714885}, issn = {0962-8452}, mesh = {Animals ; *Behavior, Animal ; *Breeding ; Female ; Herpestidae/*physiology ; Male ; }, abstract = {Evolutionary explanations of cooperative breeding based on kin selection have predicted that the individual contributions made by different helpers to rearing young should be correlated with their degree of kinship to the litter or brood they are raising. In the cooperative mongoose or meerkat, Suricata suricatta, helpers babysit pups at the natal burrow for the first month of pup life and frequent babysitters suffer substantial weight losses over the period of babysitting. Large differences in contributions exist between helpers, which are correlated with their age, sex and weight but not with their kinship to the young they are raising. Provision of food to some group members raises the contributions of individuals to babysitting. We discuss the implications of these results for evolutionary explanations of cooperative behaviour.}, } @article {pmid10686485, year = {2000}, author = {Bales, K and Dietz, J and Baker, A and Miller, K and Tardif, SD}, title = {Effects of allocare-givers on fitness of infants and parents in callitrichid primates.}, journal = {Folia primatologica; international journal of primatology}, volume = {71}, number = {1-2}, pages = {27-38}, doi = {10.1159/000021728}, pmid = {10686485}, issn = {0015-5713}, support = {R01RR02022/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Callitrichinae/*growth & development/*physiology ; Decision Making ; Female ; *Helping Behavior ; Male ; *Parenting ; Reproduction ; }, abstract = {The effects of callitrichid primate helpers (allocare-givers other than an infant's father) on the survival, reproduction or behavior of infants and parents are reviewed, using both published studies and data from free-ranging golden lion tamarins (Leontopithecus rosalia). Three lines of evidence suggest that helpers may increase their own inclusive fitness: (1) The number of adult males acting as helpers in free-ranging groups is correlated with the number of surviving infants in 3 callitrichid species. However, the lack of a negative correlation with number of infants dying suggests that activities other than direct infant care (e.g. territory defense) may be more important, especially in newly formed groups. (2) In 2 species, captive groups with helpers carry infants for longer periods of time than do groups without helpers. Whether such differences would translate into meaningful survival differences in free-ranging groups is unclear. (3) Helpers reduce the energetic burden of parents by reducing the amount of time they spend transporting or provisioning infants in at least 4 species. Reproductive males are more likely than reproductive females to benefit from the presence of helpers, reducing their investment in infant care activities as the number of helpers in the group increases. In free-ranging golden lion tamarins, the reproductive tenure of males, but not females, increases with the number of helpers in the group, suggesting that a reduction in energetic investment may translate into increased survival. 'Decisions' made by helpers to participate in infant transport are weighed against competing needs for foraging, vigilance, territory defense and, in some cases, prospecting for breeding opportunities. Given this complexity, a sophisticated model may be required to answer the question of how helpers 'decide' to participate in infant care versus other activities.}, } @article {pmid10675251, year = {2000}, author = {Bukaci&nacute;ski, D and Bukaci&nacute;ska, M and Lubjuhn, T}, title = {Adoption of chicks and the level of relatedness in common gull, Larus canus, colonies: DNA fingerprinting analyses.}, journal = {Animal behaviour}, volume = {59}, number = {2}, pages = {289-299}, doi = {10.1006/anbe.1999.1298}, pmid = {10675251}, issn = {0003-3472}, abstract = {In common gull colonies on islands of the Vistula River, Poland, adoption of chicks is common. In 1997, we observed 81 chicks from 35 nests. Of these, 19 (23.4%) left their natal broods and were adopted by other pairs. Another 11 (31.4%) were driven from the foreign territory by the owners. Foreign chicks were adopted by 15 pairs (42.9%). Eleven pairs (31.4%) drove foreign chicks from the territory. To test if the frequent adoptions in these colonies could be explained by kin selection or the occurrence of kin groups, we calculated band-sharing coefficients and genetic relatedness (r) between interacting birds (neighbours and non-neighbours). Adults that adopted were most often neighbours of the biological parents of adopted chicks, whereas spatially segregated birds, nesting further away, usually drove off the chicks. Band-sharing coefficients between males, but not females, were higher with decreasing internest distances. The band-sharing coefficients for adopted chicks and foster parents were significantly higher than for adopted chicks and randomly selected, spatially segregated pairs from the same and another colony. Band-sharing coefficients of adopted chicks and adopting neighbours (males: r=0.20; females: r=0.16) also tended to be higher than those of rejected chicks and rejecting neighbours (both sexes: r=0.08). Our results suggest that kin groups of neighbours do occur in common gull colonies. Such social structure might lead to indirect inclusive fitness benefits of adopting pairs. Differences in genetic similarity between chicks and adopting or rejecting neighbours show that at least in common gulls we should consider kin altruism as a factor in adoptions. Copyright 2000 The Association for the Study of Animal Behaviour.}, } @article {pmid10657181, year = {2000}, author = {Perrin, N and Mazalov, V}, title = {Local Competition, Inbreeding, and the Evolution of Sex-Biased Dispersal.}, journal = {The American naturalist}, volume = {155}, number = {1}, pages = {116-127}, doi = {10.1086/303296}, pmid = {10657181}, issn = {1537-5323}, abstract = {Using game theory, we developed a kin-selection model to investigate the consequences of local competition and inbreeding depression on the evolution of natal dispersal. Mating systems have the potential to favor strong sex biases in dispersal because sex differences in potential reproductive success affect the balance between local resource competition and local mate competition. No bias is expected when local competition equally affects males and females, as happens in monogamous systems and also in polygynous or promiscuous ones as long as female fitness is limited by extrinsic factors (breeding resources). In contrast, a male-biased dispersal is predicted when local mate competition exceeds local resource competition, as happens under polygyny/promiscuity when female fitness is limited by intrinsic factors (maximal rate of processing resources rather than resources themselves). This bias is reinforced by among-sex interactions: female philopatry enhances breeding opportunities for related males, while male dispersal decreases the chances that related females will inbreed. These results meet empirical patterns in mammals: polygynous/promiscuous species usually display a male-biased dispersal, while both sexes disperse in monogamous species. A parallel is drawn with sex-ratio theory, which also predicts biases toward the sex that suffers less from local competition. Optimal sex ratios and optimal sex-specific dispersal show mutual dependence, which argues for the development of coevolution models.}, } @article {pmid10623495, year = {2000}, author = {Kobayashi, Y and Yamamura, N}, title = {Evolution of seed dormancy due to sib competition: effect of dispersal and inbreeding.}, journal = {Journal of theoretical biology}, volume = {202}, number = {1}, pages = {11-24}, doi = {10.1006/jtbi.1999.1027}, pmid = {10623495}, issn = {0022-5193}, mesh = {*Biological Evolution ; Models, Biological ; *Plant Physiological Phenomena ; Reproduction ; Seeds/*physiology ; }, abstract = {The effect of dispersal and inbreeding on the evolution of seed dormancy to avoid sib competition is theoretically investigated, using a model which assumes a plant population with patchy spatial structure in a constant environment. Applying the inclusive fitness method, the evolutionarily stable dormancy rates are analytically derived for three cases: (a) an asexual haploid population, (b) a diploid-hermaphrodite population in which the dormancy rate is controlled by seeds, and (c) a diploid-hermaphrodite population in which the dormancy rate is controlled by mother plants. The evolutionarily stable dormancy rates decrease in the order of case (c), case (a), and case (b). In all the cases, the evolutionarily stable dormancy rates increase with decreasing the dispersal rate. Although inbreeding generally increases the evolutionarily stable dormancy rates, inbreeding due to selfing reduces the rate exceptionally in case (c).}, } @article {pmid10588434, year = {2000}, author = {Widdig, A and Streich, WJ and Tembrock, G}, title = {Coalition formation among male Barbary macaques (Macaca sylvanus).}, journal = {American journal of primatology}, volume = {50}, number = {1}, pages = {37-51}, doi = {10.1002/(SICI)1098-2345(200001)50:1<37::AID-AJP4>3.0.CO;2-3}, pmid = {10588434}, issn = {0275-2565}, mesh = {Age Factors ; Animals ; *Behavior, Animal ; Macaca/*psychology ; Male ; *Social Behavior ; Statistics, Nonparametric ; }, abstract = {A coalition is formed when one animal intervenes in an ongoing conflict between two parties to support one side. Since support of one party is also an act against the other party, coalitions are triadic interactions involving a supporter, a recipient, and a target. The purpose of this study was to test which of three possible theories explains coalition formation among male Barbary macaques: 1) Males support kin to enhance their indirect fitness (kin selection). 2) Males support nonkin to receive future reciprocal support (reciprocal altruism). 3) Males pursue self-interests and immediately benefit via nonkin support (cooperation). Coalition formation was investigated among 31 semi-free male Barbary macaques in the Salem Monkey Park, Germany during the mating season. The results show: 1) Males intervened more often in dyadic conflicts in which a related opponent was involved and supported related opponents more than unrelated opponents. Close kin supported each other more often than distant kin. 2) Some evidence for reciprocal support was found. However, reciprocity was probably a by-product of targeting the same individuals for dominance. 3) Coalition formation among nonkin is best interpreted as cooperation, based on self-interests. Male Barbary macaques seem to intervene more often to stabilize and less often to improve their rank. Although our data were limited, the results revealed that kin support, reciprocal support, and cooperative support were all involved in coalition formation among male Barbary macaques.}, } @article {pmid10458877, year = {1999}, author = {Osborne, KE and Oldroyd, BP}, title = {Possible causes of reproductive dominance during emergency queen rearing by honeybees.}, journal = {Animal behaviour}, volume = {58}, number = {2}, pages = {267-272}, doi = {10.1006/anbe.1999.1139}, pmid = {10458877}, issn = {0003-3472}, abstract = {When queenless honeybees, Apis mellifera, rear new queens, the relative frequencies of subfamilies found in the queen and worker brood are often very different, suggesting that certain subfamilies are reproductively dominant. At least two mechanisms could account for the observed differences in queen and worker broods. First, kin selection theory predicts that if honeybee workers are able to distinguish levels of relatedness, they should act nepotistically by favouring super-sisters over less-related half-sisters during emergency queen rearing. Alternatively, selection might result in royalty alleles that make their possessors more favoured for rearing as queens. Documented genetically based tendencies to rear queen or worker brood might interact with either of these mechanisms. To determine which of these effects might best explain reproductive dominance, we removed brood from the queenright section of one colony and offered it to the queenless section of the same colony and to three unrelated queenless colonies. We used two microsatellite loci to determine the paternity of queen and worker brood reared by these colonies. Variance in the proportions of subfamilies in queen and worker brood was greatest when the rearing bees were related to the brood. The results suggest that nepotistic interactions are more important than royalty alleles or other factors in causing reproductive dominance, but that there are complex interactions between the genotype of the nursing workers, and the genotypes of the larvae favoured for rearing as queens. Copyright 1999 The Association for the Study of Animal Behaviour.}, } @article {pmid10561133, year = {1999}, author = {Wade, MJ and Goodnight, CJ and Stevens, L}, title = {Design and Interpretation of Experimental Studies of Interdemic Selection: A Reply to Getty.}, journal = {The American naturalist}, volume = {154}, number = {5}, pages = {599-603}, doi = {10.1086/303259}, pmid = {10561133}, issn = {1537-5323}, } @article {pmid10523488, year = {1999}, author = {Bourke, AFG and Chan, GL}, title = {Queen-Worker Conflict over Sexual Production and Colony Maintenance in Perennial Social Insects.}, journal = {The American naturalist}, volume = {154}, number = {4}, pages = {417-426}, doi = {10.1086/303253}, pmid = {10523488}, issn = {1537-5323}, abstract = {An important idea from kin selection theory as applied to life-history evolution in perennial insect societies suggests that potential conflict exists between the queen and workers over the relative allocation of resources to colony reproduction and colony growth. This prediction assumed a colony with one singly mated queen, sterile workers, and independent colony foundation by dispersing queens. We argue that this prediction is mistaken because queen and workers under these circumstances can only invest in sexuals (new queens and males) derived from the colony queen. Assuming population sex ratio equilibrium, potential conflict is absent because both parties maximize fitness by maximizing the colony's total output of these sexuals. However, a similar queen-worker conflict is predicted in facultatively polygynous species in which existing queens are superseded. We hypothesize that queens favor the production of relatively more new workers to prolong their lives as reproductives, whereas workers favor raising relatively more new queens as possible replacements. We tested this hypothesis using productivity data from the ant Leptothorax acervorum. As predicted, queen number and worker number were, respectively, positively and negatively associated with the investment ratio of new workers to new queens. These findings imply a queen-worker conflict over caste determination in ants.}, } @article {pmid10433892, year = {1999}, author = {Gandon, S and Michalakis, Y}, title = {Evolutionarily stable dispersal rate in a metapopulation with extinctions and kin competition.}, journal = {Journal of theoretical biology}, volume = {199}, number = {3}, pages = {275-290}, doi = {10.1006/jtbi.1999.0960}, pmid = {10433892}, issn = {1095-8541}, abstract = {We derive an analytic expression for the evolutionarily stable dispersal rate that formalizes the balance between the effects of four factors: the cost of dispersal, the extinction rate, the coefficient of relatedness and the mode of dispersal (i.e. the probability of common origin of immigrants). This result allows us to study the effects of each factor and, more interestingly, the interactions between them. In particular, we show that the evolutionarily stable dispersal rate is not always a decreasing function of the cost of dispersal and an increasing function of relatedness. These counter-intuitive results are discussed in the light of kin selection theory. We also present the results of numerical simulations in which relatedness is not a fixed parameter but depends on different parameters including dispersal itself. We discuss these results and show how the evolutionarily stable dispersal rate is affected by the environment and the life history traits of the species. More generally, this paper presents a simple formalism allowing the study of the effects of kin selection in unstable environments (i.e. with extinctions and recolonizations). The implications of this formalism for the understanding of the evolution of other life history traits is briefly discussed. Copyright 1999 Academic Press.}, } @article {pmid10412224, year = {1999}, author = {Bradley, BJ}, title = {Levels of selection, altruism, and primate behavior.}, journal = {The Quarterly review of biology}, volume = {74}, number = {2}, pages = {171-194}, doi = {10.1086/393070}, pmid = {10412224}, issn = {0033-5770}, mesh = {*Altruism ; Animals ; Behavior, Animal ; Primates/*psychology ; *Selection, Genetic ; }, abstract = {Altruistic behaviors seem anomalous from a traditional view of Darwinian natural selection, and evolutionary explanations for them have generated much discussion. The debate centers around four major explanations: classic individual-level selection, reciprocity and game theory, kin selection, and trait-group selection. The historical context and defining criteria of each model must be reviewed before its validity can be assessed. Of these proposed mechanisms, group selection historically has been the most controversial. Although the extent to which empirical data support group selection hypotheses is uncertain, there is evidence for group-level selection among avirulent virus strains and foraging ant queens. Researchers studying mammalian behavior, particularly primatologists, have largely dismissed models of group-level selection. Most discussion of altruism among primates has focused on differences in fitness among individuals within a single group, but students of altruistic behaviors exhibited by primates also need to investigate intergroup variation with respect to these behaviors. Various altruistic behaviors are likely to have evolved through different forms of selection, and each example of apparent altruism therefore needs to be evaluated separately.}, } @article {pmid10383666, year = {1999}, author = {Chapuis, M and Keller, L}, title = {Testing kin selection with sex allocation data in eusocial hymenoptera.}, journal = {Heredity}, volume = {82 (Pt 5)}, number = {}, pages = {473-478}, doi = {10.1038/sj.hdy.6885340}, pmid = {10383666}, issn = {1365-2540}, abstract = {Sex allocation data in eusocial Hymenoptera (ants, bees and wasps) provide an excellent opportunity to assess the effectiveness of kin selection, because queens and workers differ in their relatedness to females and males. The first studies on sex allocation in eusocial Hymenoptera compared population sex investment ratios across species. Female-biased investment in monogyne (= with single-queen colonies) populations of ants suggested that workers manipulate sex allocation according to their higher relatedness to females than males (relatedness asymmetry). However, several factors may confound these comparisons across species. First, variation in relatedness asymmetry is typically associated with major changes in breeding system and life history that may also affect sex allocation. Secondly, the relative cost of females and males is difficult to estimate across sexually dimorphic taxa, such as ants. Thirdly, each species in the comparison may not represent an independent data point, because of phylogenetic relationships among species. Recently, stronger evidence that workers control sex allocation has been provided by intraspecific studies of sex ratio variation across colonies. In several species of eusocial Hymenoptera, colonies with high relatedness asymmetry produced mostly females, in contrast to colonies with low relatedness asymmetry which produced mostly males. Additional signs of worker control were found by investigating proximate mechanisms of sex ratio manipulation in ants and wasps. However, worker control is not always effective, and further manipulative experiments will be needed to disentangle the multiple evolutionary factors and processes affecting sex allocation in eusocial Hymenoptera.}, } @article {pmid10369036, year = {1999}, author = {Seto, MC and Lalumière, ML and Kuban, M}, title = {The sexual preferences of incest offenders.}, journal = {Journal of abnormal psychology}, volume = {108}, number = {2}, pages = {267-272}, doi = {10.1037//0021-843x.108.2.267}, pmid = {10369036}, issn = {0021-843X}, mesh = {Adult ; Analysis of Variance ; Case-Control Studies ; Chi-Square Distribution ; Child ; Child Abuse, Sexual/*psychology ; *Father-Child Relations ; Humans ; *Incest/classification/psychology ; Male ; *Motivation ; Pedophilia/*psychology ; Sexual Behavior/*psychology ; }, abstract = {Inclusive fitness theory suggests that discriminative solicitude and inbreeding avoidance are important mechanisms regulating parent-children interactions. From an inclusive fitness perspective, sex with one's biological children is paradoxical. The authors hypothesized that incest can occur when these mechanisms are not activated (e.g., if a father is uninvolved in child rearing) or are overwhelmed by another factor, such as pedophilic interest. They predicted that biological fathers, who presumably have been the most involved in the rearing of their victims, would show greater phallometrically measured pedophilic interest than would other incest offenders against children (e.g., grandfathers, uncles, stepfathers). The prediction was not supported. A testable alternative hypothesis to explain biological father incest is presented and the importance of assessing pedophilic interest among incest offenders is discussed.}, } @article {pmid10356387, year = {1999}, author = {Clutton-Brock, TH and O'Riain, MJ and Brotherton, PN and Gaynor, D and Kansky, R and Griffin, AS and Manser, M}, title = {Selfish sentinels in cooperative mammals.}, journal = {Science (New York, N.Y.)}, volume = {284}, number = {5420}, pages = {1640-1644}, doi = {10.1126/science.284.5420.1640}, pmid = {10356387}, issn = {0036-8075}, mesh = {Animals ; *Behavior, Animal ; *Cooperative Behavior ; Feeding Behavior ; Female ; *Herpestidae ; Male ; Nutritional Status ; }, abstract = {Like humans engaged in risky activities, group members of some animal societies take turns acting as sentinels. Explanations of the evolution of sentinel behavior have frequently relied on kin selection or reciprocal altruism, but recent models suggest that guarding may be an individual's optimal activity once its stomach is full if no other animal is on guard. This paper provides support for this last explanation by showing that, in groups of meerkats (Suricata suricatta), animals guard from safe sites, and solitary individuals as well as group members spend part of their time on guard. Though individuals seldom take successive guarding bouts, there is no regular rota, and the provision of food increases contributions to guarding and reduces the latency between bouts by the same individual.}, } @article {pmid10354628, year = {1999}, author = {Komdeur, J and Hatchwell, BJ}, title = {Kin recognition: function and mechanism in avian societies.}, journal = {Trends in ecology & evolution}, volume = {14}, number = {6}, pages = {237-241}, doi = {10.1016/s0169-5347(98)01573-0}, pmid = {10354628}, issn = {1872-8383}, abstract = {Cooperative behaviour resulting from kin selection is widespread among animals and the ability to recognize and discriminate between kin and non-kin is a critical element in kin selection theory. Current evidence suggests that associative learning is the most likely mechanism of kin discrimination. However, surprisingly, there have been no experimental studies of the putative 'associative-learning period', the likely recognition mechanisms enabling fine discrimination between close and distant kin of similar familiarity, whether generic or individual cues are employed in kin recognition, and how recognition ability varies at different stages of a species' life history. Comparative studies of kin recognition and discrimination in cooperative and noncooperative species are also needed to shed light on the adaptive value of helping behaviour and to identify key factors in the evolution of cooperation.}, } @article {pmid10053068, year = {1999}, author = {Gagneux, P and Boesch, C and Woodruff, DS}, title = {Female reproductive strategies, paternity and community structure in wild West African chimpanzees.}, journal = {Animal behaviour}, volume = {57}, number = {1}, pages = {19-32}, doi = {10.1006/anbe.1998.0972}, pmid = {10053068}, issn = {0003-3472}, abstract = {Although the variability and complexity of chimpanzee behaviour frustrates generalization, it is widely believed that social evolution in this species occurs in the context of the recognizable social group or community. We used a combination of field observations and noninvasive genotyping to study the genetic structure of a habituated community of 55 wild chimpanzees, Pan troglodytes verus, in the Taï Forest, Côte d'Ivoire. Pedigree relationships in that community show that female mate choice strategies are more variable than previously supposed and that the observed social groups are not the exclusive reproductive units. Genetic evidence based on nuclear microsatellite markers and behavioural obser-vations reveal that females in the Taï forest actively seek mating partners outside their social unit; noncommunity males accounted for half the paternities over 5 years. This female mating strategy increases male gene flow between communities despite male philopatry, and negates the predicted higher relatedness among community males. Kin selection seems unlikely to explain the frequent cooperation and sharing observed among group males in this population. Similarly, inbreeding avoidance is probably not the sole cause of permanent adolescent female dispersal as a combination of extragroup mating and avoidance of incest with home group males would allow females to avoid inbreeding without the hazards associated with immigration into a new community. Extragroup mating as part of chimpanzee females' reproductive strategy may allow them to choose from a wider variety and number of males, without losing the resources and support provided by their male social group partners. Copyright 1999 The Association for the Study of Animal Behaviour.}, } @article {pmid10049483, year = {1999}, author = {Schaeff, CM and Boness, DJ and Bowen, WD}, title = {Female distribution, genetic relatedness, and fostering behaviour in harbour seals, Phoca vitulina.}, journal = {Animal behaviour}, volume = {57}, number = {2}, pages = {427-434}, doi = {10.1006/anbe.1998.1001}, pmid = {10049483}, issn = {0003-3472}, abstract = {Although harbour seals may not recognize their relatives, relatives could be chosen preferentially for fostering (i.e. kin selection) if harbour seals display natal philopatry coupled with breeding site fidelity, and thus kin are clustered within the colony. We used behavioural and genetic data to investigate population structure within the Sable Island breeding colony and to test whether harbour seals tend to foster related pups. Adult females on Sable Island showed a high level of breeding-colony site fidelity but low levels of within-colony site fidelity both within and between years. Similarly, although lactating females showed a clumped distribution, group composition was highly variable, suggesting that this study colony was not composed of groups of related animals. DNA fingerprint data supported the hypothesis that female distribution within the colony was not correlated with genetic relatedness. Furthermore, the mean DNA band sharing among foster dyads did not differ significantly from that for unrelated animals. These results indicate that among harbour seals, related pups are not usually chosen preferentially for fostering and hence, kin selection is not likely to be influencing the occurrence of this behaviour. Copyright 1999 The Association for the Study of Animal Behaviour.}, } @article {pmid9933551, year = {1998}, author = {Brown, KM}, title = {Proximate and ultimate causes of adoption in ring-billed gulls.}, journal = {Animal behaviour}, volume = {56}, number = {6}, pages = {1529-1543}, doi = {10.1006/anbe.1998.0913}, pmid = {9933551}, issn = {0003-3472}, abstract = {From 1987 to 1994, the annual frequency of adoption by breeding pairs at a Lake Erie ring-billed gull, Larus delawarensis, colony ranged from 3 to 37% (average 8%/year, N=7 years) and, on average, foster parents raised 0.5 fewer of their own chicks to fledging than pairs that did not adopt. The key evolutionary question is: why do some individuals apparently suffer the costs associated with a behaviour that appears to enhance the fitness of others? From 1992 to 1995, I investigated the proximate and ultimate causes of adoption in ring-billed gulls from the perspectives of both the foster parents and adopted chicks, and tested predictions that differentiated between various competing adaptive and nonadaptive hypotheses that have been proposed to explain it. While I was able to demonstrate a breeding cost, I failed to identify any benefits to foster parents. Thus, the adaptive hypotheses that rely on the foster parents benefiting were not supported (e.g. kin selection, reciprocal altruism, acquisition of parenting experience). From the foster parent's perspective, adoption was mediated through errors in parent-offspring recognition. Under natural conditions, most fostering pairs were tending small chicks (<6 days old) at the time of adoptions; in chick-transfer experiments, resident parents did not discriminate against foreign chicks until their own chicks were 7-9 days old. Chicks (N=25) that subsequently abandoned their natal nests were lighter, and grew at a slower rate, than chicks that survived to fledging in their home broods. Thus, departing chicks were at a survival disadvantage in their home broods. Chicks that gained acceptance into foreign broods where they were older/larger than the resident chicks realized high survival at the expense of their foster siblings and parents. Based upon individual growth rates and the corresponding survival probabilities, disadvantaged chicks approximately doubled their survival chances through foster care. Why has selection not eliminated adoption? I argue that adoption is an evolutionary arms race between the two principle actor groups; disadvantaged chicks, which benefit through foster care, and host parents, which avoid providing foster care (e.g. infanticide). In ring-billed gulls, selection has failed to eliminate adoption because the long-term reproductive cost (estimated at 4%, this study) of an occasional adoption is probably offset by the relatively higher costs associated with stricter kin discrimination mechanisms (e.g. parental infanticide). (c) 1998 The Association for the Study of Animal Behaviour.}, } @article {pmid10322621, year = {1999}, author = {Brown, RM and Dahlen, E and Mills, C and Rick, J and Biblarz, A}, title = {Evaluation of an evolutionary model of self-preservation and self-destruction.}, journal = {Suicide & life-threatening behavior}, volume = {29}, number = {1}, pages = {58-71}, pmid = {10322621}, issn = {0363-0234}, mesh = {Adolescent ; Adult ; Biological Evolution ; *Cost of Illness ; *Family Relations ; Female ; Humans ; Male ; *Models, Biological ; Psychiatric Status Rating Scales ; Regression Analysis ; Reproduction ; *Self-Injurious Behavior/physiopathology/psychology ; Sexual Behavior/psychology ; Suicide/psychology ; Surveys and Questionnaires ; Survival/physiology ; }, abstract = {According to deCatanzaro's mathematical model of self-preservation and self-destruction, staying alive actually may reduce inclusive fitness for an individual who is low in reproductive potential and, at the same time, poses such a burden to close kin that it costs them opportunities for reproduction. Predictions generated from this model were tested using 175 university students as subjects and variables constructed from a 164-item questionnaire. The criterion variables were separate measures of depression, hopelessness, and suicide ideation and behavior. The predictor variables derived from the model were separate measures of reproductive potential of the individual, the individual's perceived benefit or cost to kin, and reproductive potential of the individual's kin. As predicted, there were negative and significant bivariate correlations between each of the model-generated predictor variables and one or more of the criterion variables. Multiple regression analyses showed that benefit to kin was the best predictor of both depression and hopelessness. Discriminant analysis showed that reproductive potential of kin significantly differentiated suicide attempters from nonattempters. Overall, our results support and extend deCatanzaro's model and empirical findings.}, } @article {pmid9875959, year = {1998}, author = {Bailey, KG and Wood, HE}, title = {Evolutionary kinship therapy: basic principles and treatment implications.}, journal = {The British journal of medical psychology}, volume = {71 (Pt 4)}, number = {}, pages = {509-523}, doi = {10.1111/j.2044-8341.1998.tb01006.x}, pmid = {9875959}, issn = {0007-1129}, mesh = {*Biological Evolution ; Humans ; *Interpersonal Relations ; Pedigree ; Psychology/trends ; *Psychotherapy ; *Social Behavior ; }, abstract = {The idiom of kinship is a powerful one that stretches across many levels of social behaviour (van den Berghe, 1979), and Daly, Salmon & Wilson (1997) recently outlined the basic principles of a comprehensive, evolution-based kinship psychology. Their approach merges traditional kinship theory, Hamilton's inclusive fitness model and the broader realm of evolutionary psychology into an exciting and provocative call to arms. They address biological, psychological (viz. fictive kinship) and kin-like levels of analysis, and they argue for a relationship-specific kinship psychology that deals with the particular demands of being a mother, father, mate, offspring or grandparent. Our particular approach to kinship psychology has focused primarily on the distinction between biological kinship and psychological kinship (Bailey, 1988; Bailey & Wood, 1993; Nava & Bailey, 1991), and more recently on the role of kin-like relations in psychotherapy and other social contexts (Bailey, 1997a; Wood, 1997). The kin-like category is especially noteworthy in modern industrialized countries where acquaintanceships and stranger-to-stranger interactions often predominate over biological and psychological kinships (Ahern & Bailey, 1997).}, } @article {pmid9872579, year = {1998}, author = {Muir, WM and Craig, JV}, title = {Improving animal well-being through genetic selection.}, journal = {Poultry science}, volume = {77}, number = {12}, pages = {1781-1788}, doi = {10.1093/ps/77.12.1781}, pmid = {9872579}, issn = {0032-5791}, mesh = {Adaptation, Physiological/genetics ; *Animal Welfare ; Animals ; Behavior, Animal ; Chickens/*genetics ; Environment ; Female ; Oviposition ; *Selection, Genetic ; }, abstract = {This paper reviews the possibilities of adapting laying hens to cages by means of genetic selection. By selecting separately for rate of lay and longevity using a kin selection method, a strain of laying hen has been developed that shows much less feather pecking and cannibalism than a control strain, and with no decrease in productivity. This experimental strain enjoys a higher level of welfare in cages because it does not require beak trimming.}, } @article {pmid9784219, year = {1998}, author = {Ekvall, K}, title = {Effects of social organization, age and aggressive behaviour on allosuckling in wild fallow deer.}, journal = {Animal behaviour}, volume = {56}, number = {3}, pages = {695-703}, doi = {10.1006/anbe.1998.0825}, pmid = {9784219}, issn = {0003-3472}, abstract = {I investigated the occurrence, frequency and distribution of allosuckling in a wild population of fallow deer, Dama dama, throughout the lactation period during 1992 in southern Sweden. A total of 292 suckling bouts were observed in four groups; in 43% of these, fawns were seen sucking from a female that was not the mother. Allosuckling occurred in a higher percentage of suckling bouts as the lactation period progressed and all 16 fawns participated to various degrees. Of the 16 females, 13 suckled nonoffspring fawns but their behaviour towards these fawns varied greatly. Allosuckling was positively correlated with the age of the females and negatively correlated with the rate of their aggressive behaviour. Since allosuckling was not performed between groups but was common between related members in a stable social unit and was expressed reciprocally between the oldest individuals in the group, allosuckling could be a result of kin selection and/or reciprocal altruism. Copyright 1998 The Association for the Study of Animal Behaviour.}, } @article {pmid9778445, year = {1998}, author = {Day, T and Taylor, PD}, title = {Unifying genetic and game theoretic models of kin selection for continuous traits.}, journal = {Journal of theoretical biology}, volume = {194}, number = {3}, pages = {391-407}, doi = {10.1006/jtbi.1998.0762}, pmid = {9778445}, issn = {0022-5193}, mesh = {Animals ; *Game Theory ; *Models, Genetic ; Phenotype ; *Quantitative Trait, Heritable ; *Selection, Genetic ; }, abstract = {A framework is presented for unifying single locus genetic and game theoretic models of continuous traits under frequency-dependent selection when there are interactions among relatives. This framework serves two purposes. First, it is used to determine how "games between relatives" must be modeled to be genetically valid. There are two commonly employed phenotypic approaches used in this setting, and we demonstrate that, although some of their predictions are always genetically valid, others are invalid in general, and this is true for both haploid asexual and diploid sexual organisms. In particular, we show that both approaches obtain the correct equilibrium and convergence stability conditions, but neither obtains the correct condition for evolutionary stability. Unlike earlier results for discrete trait matrix games (Hines & Maynard Smith, 1979), there is no simple correspondence between phenotypic and genetic predictions, and we provide two examples to illustrate this point. It is possible however, to obtain these earlier results within the present setting by restricting attention to a particular class of fitness functions. These results demonstrate that, even when selection is weak, phenotypic models can fail if fitness is frequency-dependent. The second purpose is to determine when population mean inclusive fitness effect provides an adaptive topography in games between relative. Our results show that the fitness function must have a special form for this to be true, and this form differs between haploid and diploid organisms.}, } @article {pmid9777050, year = {1998}, author = {Akiskal, HS}, title = {Toward a definition of generalized anxiety disorder as an anxious temperament type.}, journal = {Acta psychiatrica Scandinavica. Supplementum}, volume = {393}, number = {}, pages = {66-73}, doi = {10.1111/j.1600-0447.1998.tb05969.x}, pmid = {9777050}, issn = {0065-1591}, mesh = {Animals ; Anxiety Disorders/classification/*diagnosis/psychology ; Arousal ; Chronic Disease ; Depressive Disorder/classification/diagnosis/psychology ; Humans ; Panic Disorder/classification/diagnosis/psychology ; Personality Development ; *Temperament ; }, abstract = {Generalized anxiety disorder (GAD) is defined as an uncontrollable disposition to worry about one's welfare and that of one's immediate kin. Associated manifestations include arousal, vigilance, tension, irritability, unrestful sleep and gastrointestinal distress. There is growing evidence for the lifelong nature of this condition among many of its sufferers. This and other evidence reviewed in the present paper provide further support for the thesis that the chronic disposition to worry should probably be classified under constitutional or trait anxiety. GAD is best considered an exaggeration of a normal personality disposition that can be named 'Generalized anxious temperament' (GAT). Despite some overlap with anxious-phobic, inhibited and avoidant-sensitive temperaments, GAT seems to have a distinct profile with altruistic overtones; on the other hand, GAT is less easily distinguished from harm-avoidant and obsessive traits. That worrying would increase upon relaxation is not a paradox at all, and is understandable in an ethological perspective as subserving the defensive function of being vigilant of ever present yet uncertain external dangers--to oneself and one's kin--in day-to-day living. GAT can thus be considered as 'altruistic anxiety', subserving hypothetically the survival of one's extended phenotype in a 'kin selection' paradigm. Only when extreme does worrying manifest in a clinical context, impairing one's interpersonal life and functioning at work, and increasing use of general health care resources. Furthermore, generalized anxiety appears to predispose to and is often associated with depression, and a spectrum of phobic disorders, as well as alcohol and sedative use. These considerations place GAD (and the putative GAT) in the limelight and underscore the need for more research into its fundamental characteristics. Towards this aim, a self-rated GAT measure under development in our center is provided in an appendix to this paper.}, } @article {pmid9750181, year = {1998}, author = {van Baalen M, and Rand, DA}, title = {The Unit of Selection in Viscous Populations and the Evolution of Altruism.}, journal = {Journal of theoretical biology}, volume = {193}, number = {4}, pages = {631-648}, doi = {10.1006/jtbi.1998.0730}, pmid = {9750181}, issn = {1095-8541}, abstract = {Group selection can overcome individual selection for selfishness and favour altruism if there is variation among the founders of the spatially distinct groups, and groups with many altruists become substantially larger (or exist longer) than groups with few. Whether altruism can evolve in populations that do not have an alternation of local population growth and global dispersal ("viscous populations") has been disputed for some time. Limited dispersal protects the altruists from the non-altruists, but also hinders the export of altruism. In this article, we used the Pair Approximation technique (tracking the dynamics of pairs of neighbours instead of single individuals) to derive explicit invasion conditions for rare mutants in populations with limited dispersal. In such viscous populations, invading mutants form clusters, and ultimately, invasion conditions depend on the properties of such clusters. Thus there is selection on a higher level than that of the individual; in fact, invasion conditions define the unit of selection in viscous populations. We treat the evolution of altruism as a specific example, but the method is of more general interest. In particular, an important advantage is that the spatial aspects can be incorporated into game theory in a straightforward fashion; we will specify the ESS for a more general model. The invasion condition can be interpreted in terms of inclusive fitness. In contrast with Hamilton's model, the coefficient of relatedness is not merely a given genetical constant but depends on local population dynamical processes (birth, dispersal and death of individuals). With a simple birth rate function, Hamilton's rule is recovered: the cost to the donor should be less than the benefit to the recipient weighted with the coefficient of relatedness. As the coefficient of relatedness is roughly proportional to an individual's number of neighbours, benefits to the recipient must be substantial to outweigh the costs, confirming earlier studies. We discuss the consequences for the evolution of dispersal and outline how the method may be extended to study evolution in interacting populations.Copyright 1998 Academic Press}, } @article {pmid9714935, year = {1998}, author = {Lewis, K}, title = {Pathogen resistance as the origin of kin altruism.}, journal = {Journal of theoretical biology}, volume = {193}, number = {2}, pages = {359-363}, doi = {10.1006/jtbi.1998.0725}, pmid = {9714935}, issn = {0022-5193}, support = {R01GM54412-01/GM/NIGMS NIH HHS/United States ; }, mesh = {*Altruism ; Animals ; Bacterial Infections/*genetics ; Female ; *Genes, MHC Class I ; *Genes, MHC Class II ; Humans ; Immunity, Innate/*genetics ; Male ; Mice ; Parasitic Diseases/*genetics ; Pedigree ; Sexual Behavior ; Specific Pathogen-Free Organisms ; }, abstract = {It is suggested that pathogen and parasite avoidance act as a driving force for kin selection. Preferential association with relatives decreases the probability of infection with unfamiliar pathogens. Altruistic behavior towards kin will further decrease the danger of infection by increasing the representation of relatives in a group. Such a behavioral strategy could evolve if pathogen resistance were heritable. Highly polymorphic major histocompatibility (MHC) genes largely determine heritable resistance to particular pathogens. The degree of relatedness within a group correlates with the degree of similarity in MHCs. It has been shown that detection of MHC type by mice guides preferential kin association. Pathogen avoidance appears to be the simplest explanation for the existence of a direct link between detecting the heritable component of the immune system and kin altruism. Detection of MHC also serves kin avoidance in mating. Periodic introduction of new genes including MHCs through mating provides resistance to the unavoidable appearance of foreign virulent pathogens (Hamilton et al., 1990, Proc. Natl Acad. Sci. U.S.A. 87, 3566-3573). It is suggested that kin preference favoring homogeneity punctuated by introduction of new genes through mating provides an optimal strategy for pathogen avoidance. Aggression might also serve to decrease infection by isolating or eliminating individuals with unrelated MHCs.}, } @article {pmid9653725, year = {1998}, author = {Maynard Smith, J}, title = {The units of selection.}, journal = {Novartis Foundation symposium}, volume = {213}, number = {}, pages = {203-11; discussion 211-7}, pmid = {9653725}, issn = {1528-2511}, mesh = {Animals ; *Models, Biological ; *Selection, Genetic ; }, abstract = {Darwin's idea of evolution by natural selection is almost universally accepted by biologists, but debate continues about the units of selection. The history of this debate starts with Wynne-Edwards' arguments for group selection, and Hamilton's explantation of social behaviour in terms of the inclusive fitness of individuals. Hamilton's approach differs from the gene-centred approach pioneered by Williams and Dawkins, although both the problem and its solution are essentially the same. The choice of approach depends on conceptual and mathematical simplicity, and on one's attitude to the causal efficacy of genes. The problem of selection on units above the species level is discussed. Today, we are in the main concerned with cases in which selection acts simultaneously at two levels. This is true of current research on intragenomic conflict and of the suggestion by Maynard Smith and Szathmáry that in the major transitions in evolution, entities that were capable of independent replication before the transition can only replicate as part of a larger whole after it.}, } @article {pmid9634232, year = {1998}, author = {Nowak, MA and Sigmund, K}, title = {Evolution of indirect reciprocity by image scoring.}, journal = {Nature}, volume = {393}, number = {6685}, pages = {573-577}, doi = {10.1038/31225}, pmid = {9634232}, issn = {0028-0836}, mesh = {Altruism ; *Biological Evolution ; Computer Simulation ; *Cooperative Behavior ; Helping Behavior ; Humans ; Mutation ; Selection, Genetic ; }, abstract = {Darwinian evolution has to provide an explanation for cooperative behaviour. Theories of cooperation are based on kin selection (dependent on genetic relatedness), group selection and reciprocal altruism. The idea of reciprocal altruism usually involves direct reciprocity: repeated encounters between the same individuals allow for the return of an altruistic act by the recipient. Here we present a new theoretical framework, which is based on indirect reciprocity and does not require the same two individuals ever to meet again. Individual selection can nevertheless favour cooperative strategies directed towards recipients that have helped others in the past. Cooperation pays because it confers the image of a valuable community member to the cooperating individual. We present computer simulations and analytic models that specify the conditions required for evolutionary stability of indirect reciprocity. We show that the probability of knowing the 'image' of the recipient must exceed the cost-to-benefit ratio of the altruistic act. We propose that the emergence of indirect reciprocity was a decisive step for the evolution of human societies.}, } @article {pmid9549234, year = {1998}, author = {Segal, NL and MacDonald, KB}, title = {Behavioral genetics and evolutionary psychology: unified perspective on personality research.}, journal = {Human biology}, volume = {70}, number = {2}, pages = {159-184}, pmid = {9549234}, issn = {0018-7143}, mesh = {*Biological Evolution ; *Genetics, Behavioral ; Humans ; *Personality ; Psychology ; }, abstract = {Behavioral geneticists and evolutionary psychologists have generally pursued human behavioral analyses with little theoretical or methodological exchange. However, significant benefits might accrue from increased communication between these disciplines. The primary goals of this article are (1) to identify meaningful junctures between behavioral genetics and evolutionary psychology, (2) to describe behavioral genetic research designs and their applications to evolutionary analyses, and (3) to reassess current personality research in light of behavioral genetic and evolutionary concepts and techniques. The five-factor model of personality is conceptualized as subsuming variation in normative species-typical systems with adaptive functions in the human environment of evolutionary adaptation. Considered as universal evolved mechanisms, personality systems are often seen in dynamic conflict within individuals and as highly compartmentalized in their functioning between settings. However, genetically influenced individual differences in personality may also be understood within an evolutionary framework. Studies of the heritability of personality traits indicate broad-sense heritabilities in the 0.40-0.50 range with evidence of substantial nonadditive genetic variation and nonshared environmental influences. Evidence indicates that evolutionary theory (e.g., inclusive fitness theory) predicts patterns of social interaction (e.g., cooperation and bereavement) in relatives. Furthermore, variation in personality may constitute a range of viable strategies matching the opportunities available in the complex niche environment of human societies. Within this wide range of viable strategies, personality variation functions as a resource environment for individuals in the sense that personality variation is evaluated according to the interests of the evaluator (e.g., friendships, coalitions, or mate choice).}, } @article {pmid9521799, year = {1997}, author = {Tilley, CA and Oldroyd, BP}, title = {Unequal subfamily proportions among honey bee queen and worker brood.}, journal = {Animal behaviour}, volume = {54}, number = {6}, pages = {1483-1490}, doi = {10.1006/anbe.1997.0546}, pmid = {9521799}, issn = {0003-3472}, abstract = {Queens from three colonies of feral honey bees, Apis mellifera were removed and placed in separate nucleus colonies. For each colony, eggs and larvae were taken from the nucleus and placed in the main hive on each of 3-4 consecutive weeks. Workers in the queenless parts selected young larvae to rear as queens. Queen pupae, together with the surrounding worker pupae, were removed from each colony and analysed at two to three microsatellite loci to determine their paternity. In all three colonies, the paternity of larvae chosen by the bees to rear as queens was not a random sample of the paternities in the worker brood, with certain subfamilies being over-represented in queens. These results support an important prediction of kin selection theory: when colonies are queenless, unequal relatedness within colonies could lead to the evolution of reproductive competition, that is some subfamilies achieving greater reproductive success than others. The mechanism by which such dominance is achieved could be through a system of kin recognition and nepotism, but we conclude that genetically based differential attractiveness of larvae for rearing as queens is more likely.Copyright 1997 The Association for the Study of Animal BehaviourCopyright 1997The Association for the Study of Animal Behaviour.}, } @article {pmid9514667, year = {1998}, author = {Tarpy, DR and Fletcher, DJC}, title = {Effects of relatedness on queen competition within honey bee colonies.}, journal = {Animal behaviour}, volume = {55}, number = {3}, pages = {537-543}, doi = {10.1006/anbe.1997.0617}, pmid = {9514667}, issn = {0003-3472}, abstract = {The influence of relatedness on the pre- and post-emergent survival of honey bee queens was investigated. Workers did not preferentially rear sisters over non-siblings under conditions of natural queen replacement. After queen emergence, however, there was a significant effect of a queen's relatedness to the workers on her survivorship during fights with rival queens. The mechanism of this bias towards related queens is unknown, and several hypotheses are discussed. The difference in post-emergent survivability suggests that kin selection may operate during competition among adult queens at this crucial stage of honey bee reproduction. Copyright 1998 The Association for the Study of Animal Behaviour Copyright 1998 The Association for the Study of Animal Behaviour.}, } @article {pmid9480682, year = {1998}, author = {Cant, MA}, title = {A model for the evolution of reproductive skew without reproductive suppression.}, journal = {Animal behaviour}, volume = {55}, number = {1}, pages = {163-169}, doi = {10.1006/anbe.1997.0589}, pmid = {9480682}, issn = {0003-3472}, abstract = {Reproductive skew is a measure of the way breeding is distributed among the members of an animal society or group. Up to now, explanations of patterns of skew have been limited to one particular model, which assumes that a single dominant has full control over the distribution of subordinate reproduction. If this control is incomplete or absent, however, unsanctioned breeding by subordinate females will increase the total number of young produced. Here I present a new model for the evolution of skew that considers the effect of brood size on the inclusive fitness of dominants and subordinates. By augmenting brood size, a subordinate female reduces the per capita fitness of a dominant's offspring, so the net benefits of producing young are lower for related subordinates. I consider the stable level of skew when both dominant and subordinate attempt to maximize their inclusive fitness under two conditions: (1) when the dominant is unable to anticipate that a subordinate will add to her brood; and (2) the dominant does anticipate subordinate reproduction and can respond by adjusting her own brood size. In the first case, the model predicts that reproductive skew will increase with relatedness between breeders, because related subordinates are selected to add fewer young to the dominant's brood. In the second case, the dominant's optimal response to the presence of a second breeder exaggerates the relationship between relatedness and skew: dominants should produce more young when breeding with related compared with unrelated subordinates. Copyright 1998 The Association for the Study of Animal Behaviour.}, } @article {pmid9441823, year = {1997}, author = {Frank, SA}, title = {Multivariate analysis of correlated selection and kin selection, with an ESS maximization method.}, journal = {Journal of theoretical biology}, volume = {189}, number = {3}, pages = {307-316}, doi = {10.1006/jtbi.1997.0516}, pmid = {9441823}, issn = {0022-5193}, mesh = {Animals ; *Biological Evolution ; Genotype ; Models, Biological ; Multivariate Analysis ; Phenotype ; *Selection, Genetic ; *Social Behavior ; }, abstract = {Kin selection coefficients are used in two distinct ways. First, these coefficients measure phenotypic correlations that affect the marginal costs and benefits of behaviors. For example, the phenotypic correlation in sex ratio produced by two females in an isolated patch influences the favoured sex ratio. Second, kin selection coefficients describe genotypic correlations that measure fidelity of transmission. For example, a female values daughters vs. nieces according to genotypic correlations. It is widely known that kin selection coefficients may be interpreted as phenotypic or genotypic correlations in different contexts. However, these different interpretations have never been fully separated, and their different role have not been clearly explained. I provide proofs of a generic analytical approach. The technique automatically separates phenotypic correlations among social partners from genotypic components of transmission. The result is a general method that can be derived from first principles and applied to multivariate problems in social evolution. I emphasize a simple, practical maximization method that can be used to calculate equilibrium conditions for complex social interactions.}, } @article {pmid9465418, year = {1998}, author = {Perry, EA and Boness, DJ and Fleischer, RC}, title = {DNA fingerprinting evidence of nonfilial nursing in grey seals.}, journal = {Molecular ecology}, volume = {7}, number = {1}, pages = {81-85}, doi = {10.1046/j.1365-294x.1998.00313.x}, pmid = {9465418}, issn = {0962-1083}, mesh = {Animals ; Animals, Suckling/*genetics ; Behavior, Animal ; *DNA Fingerprinting ; Female ; Maternal Behavior/*physiology ; Seals, Earless/*physiology ; }, abstract = {We tested the hypothesis that kin selection may play a role in fostering behaviour in grey seals. Fostering frequency varied among three colonies, ranging from 3% to 28%. Band-sharing coefficients (S) of DNA fingerprints, from two multilocus probes, were used to predict relatedness (r). Mean r did not differ between foster mother-pup pairs and the expected r = 0 for presumed unrelated female-pup pairs. Likewise, mean r between fostered and filial pups compared to r between presumed unrelated pups within the same beaches did not differ. Mean S values of presumed unrelated pups on different beaches within the two smallest colonies were indistinguishable, indicating that there is not increased variation in relatedness in small colonies. These results suggest that kin selection does not play a significant role in the maintenance of grey seal fostering behaviour.}, } @article {pmid9445801, year = {1997}, author = {Gordeev, MI and Perevozkin, VP}, title = {[Kin selection and developmental rate of malarial mosquitoes with different karyotypes].}, journal = {Genetika}, volume = {33}, number = {10}, pages = {1367-1373}, pmid = {9445801}, issn = {0016-6758}, mesh = {Adaptation, Physiological ; Animals ; Anopheles/*genetics/growth & development ; Genotype ; Karyotyping ; Larva/growth & development ; *Selection, Genetic ; }, abstract = {Changes in the adaptive value of genotypes through the course of relationships within and between malaria mosquito families at larval stages were studied in Anopheles messeae, the species with chromosome polymorphism. It was shown that interactions between sibs can affect their viability and developmental rate. Larvae with "northern" inversions (r-strategists) developed significantly slower when kept together with larvae carrying the "southern" chromosome variants (K-strategists). A decrease in relative fitness was observed in larvae with the northern inversion XL1, which were kept on an insufficient diet. The relationship between kin selection and the formation of adaptive strategies in A. messeae are discussed.}, } @article {pmid9404029, year = {1997}, author = {Haig, D}, title = {Parental antagonism, relatedness asymmetries, and genomic imprinting.}, journal = {Proceedings. Biological sciences}, volume = {264}, number = {1388}, pages = {1657-1662}, pmid = {9404029}, issn = {0962-8452}, mesh = {Animals ; Evolution, Molecular ; Female ; *Genomic Imprinting ; Insulin-Like Growth Factor II/genetics ; Male ; Mathematical Computing ; Mice ; *Models, Genetic ; Receptor, IGF Type 2/genetics ; Sex Factors ; }, abstract = {The theory of inclusive fitness can be modified to consider separate coefficients of relatedness for an individual's maternal and paternal alleles. A gene is said to have parentally antagonistic effects if it has an inclusive fitness benefit when maternally derived, but an inclusive fitness cost when paternally derived (or vice versa). Parental antagonism favours the evolution of alleles that are expressed only when maternally derived or only when paternally derived (genomic imprinting).}, } @article {pmid9394460, year = {1997}, author = {Garza, JC and Dallas, J and Duryadi, D and Gerasimov, S and Croset, H and Boursot, P}, title = {Social structure of the mound-building mouse Mus spicilegus revealed by genetic analysis with microsatellites.}, journal = {Molecular ecology}, volume = {6}, number = {11}, pages = {1009-1017}, doi = {10.1046/j.1365-294x.1997.00278.x}, pmid = {9394460}, issn = {0962-1083}, support = {GM 40282/GM/NIGMS NIH HHS/United States ; }, mesh = {Alleles ; Animals ; Behavior, Animal/*physiology ; Female ; Genetics, Population ; Haplotypes ; Heterozygote ; Male ; Mice ; *Microsatellite Repeats ; Models, Genetic ; Muridae/*physiology ; Polymorphism, Genetic ; Reproduction/genetics ; Sex Ratio ; X Chromosome ; }, abstract = {The Mound-building mouse Mus spicilegus possesses a unique behaviour amongst mice. It constructs large earthen mounds and associated nesting chambers which serve to store food for immature individuals during the winter nesting period. We have used genetic analysis of four autosomal and four X-linked microsatellite loci to determine relationships between individuals inhabiting 40 mounds in Bulgaria. We show that, in almost all cases, individuals in a mound are the product of multiple parentage. We estimate the minimum number of males and female parents contributing offspring to each mound and demonstrate that at least two male and two female parents contribute offspring to a minimum of seven mounds. Analyses of relatedness coefficients and allele sharing values demonstrate that parents of different sibships within mounds are more related than if they had been chosen at random from the population and suggest that it is the female parents that contribute this excess relatedness. These results suggest that the mechanism by which individuals congregate to build mounds is kin-based and that the evolution of mound building and communal nesting in M. spicilegus is due in part to kin selection. This study represents a novel approach to the study of mammalian behavioural ecology. We have used a genetic dataset to construct an outline of social structure in the absence of behavioural data. These inferences can now be used to direct further work on this species.}, } @article {pmid9344438, year = {1997}, author = {Heinze, J and Puchinger, W and HOLLDOBLER, B}, title = {Worker reproduction and social hierarchies in Leptothorax ants.}, journal = {Animal behaviour}, volume = {54}, number = {4}, pages = {849-864}, doi = {10.1006/anbe.1996.0511}, pmid = {9344438}, issn = {0003-3472}, abstract = {Kin selection theory predicts the existence of potential conflict between queen and workers and among workers concerning the production of males in insect societies with a single, once-mated queen. We investigated the occurrence of reproductive conflict and worker reproduction in both single- and multi-queen colonies of 10 species of the ant genus LeptothoraxIn contrast to previous observations in related species, workers only infrequently engaged in aggressive interactions and did not lay large numbers of eggs in colonies containing queens. Allozyme analyses of queens, workers and males suggest that the contribution of workers to the males produced in colonies with queens is indeed minimal, at least in L. unifasciatusWhen the queens died or were experimentally removed from the colonies, in most species dominance interactions among workers became significantly more frequent and one or several high-ranking workers started to lay eggs. Workers with an increased number of ovarioles per ovary apparently had a reproductive advantage over workers with normal ovaries.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour}, } @article {pmid9299041, year = {1997}, author = {Goldberg, TL and Wrangham, RW}, title = {Genetic correlates of social behaviour in wild chimpanzees: evidence from mitochondrial DNA.}, journal = {Animal behaviour}, volume = {54}, number = {3}, pages = {559-570}, doi = {10.1006/anbe.1996.0450}, pmid = {9299041}, issn = {0003-3472}, abstract = {This study explored some aspects of chimpanzee social behaviour using mitochondrial DNA sequence data as an index of matrilineal relatedness. The hypothesis tested was that matrilineal relatedness predicts social affiliative preference in wild chimpanzees. Several behavioural measures of individual social preference were examined for chimpanzees from Kanyawara community in Uganda's Kibale Forest. None of the four pairs of strongly affiliative males in this community could have been maternal brothers, since no pair shared the same mitochondrial DNA sequence. Fourteen chimpanzee communities outside Kibale, for which no direct behavioural data were available, were also studied by using communal nesting as a rough index of affiliative preference. Again, chimpanzees that nested together did not tend to be matrilineally related. The results suggest that kin selection is weaker than previously thought as a force promoting intra-community affiliation in chimpanzees.1997The Association for the Study of Animal Behaviour}, } @article {pmid9378143, year = {1997}, author = {Crozier, RH and Oldroyd, BP and Tay, WT and Kaufmann, BE and Johnson, RN and Carew, ME and Jennings, KM}, title = {Molecular advances in understanding social insect population structure.}, journal = {Electrophoresis}, volume = {18}, number = {9}, pages = {1672-1675}, doi = {10.1002/elps.1150180934}, pmid = {9378143}, issn = {0173-0835}, mesh = {Animals ; Ants/genetics ; Australia ; Bees/genetics ; Biological Evolution ; DNA, Mitochondrial/analysis ; Female ; Genetic Markers ; Insecta/*genetics ; Minisatellite Repeats ; Social Behavior ; }, abstract = {Social insects present many phenomena seen in all organisms but in more extreme forms and with larger sample sizes than those observable in most natural populations of vertebrates. Microsatellites are proving very much more informative than allozymes for the analysis of population biological problems, and prolifically polymorphic markers are fairly readily developed. In addition, the male-haploid genetic system of many social insects facilitates genetic analysis. The ability to amplify DNA from sperm stored in a female's sperm storage device enables the determination of mating types long after the death of the short-lived males, in addition to information on the degree of mixing of sperm from different males. Mitochondrial (mt) DNA sequences are also proving important, not only in phylogenetic studies but also in molecular population genetics, as a tracer of female movements. Mitochondrial markers have definitively shown the movement of females between colonies, challenging models giving exclusive primacy to kin selection as the explanation for multiqueen colonies, in Australian meat ants, Iridomyrmex purpureus, and the aridzone queenless ant Rhytidoponera sp. 12. Microsatellite and mtDNA variation are being studied in Camponotus consobrinus sugar ants, showing an unexpected diversity of complexity in colony structure, and microsatellites have shown that transfer of ants between nests of the weaver ant Polyrhachis doddi must be slight, despite an apparent lack of hostility.}, } @article {pmid18811314, year = {1997}, author = {Frank, SA}, title = {Models of symbiosis.}, journal = {The American naturalist}, volume = {150 Suppl 1}, number = {}, pages = {S80-99}, doi = {10.1086/286051}, pmid = {18811314}, issn = {0003-0147}, abstract = {A tentative outline of concepts is proposed for the evolutionary genetics of symbiosis. There are three main topics. The first concerns the tension between the integrative and disruptive forces of kin selection. Kin selection can be disruptive because competition among close relatives favors dispersal and a reduction in relatedness among neighbors. Kin selection acts independently within each species of a symbiotic community but has important consequences for the integration of the community into a cooperative unit. The second topic describes the evolution of beneficial, synergistic effects between species. The evolution of mutual effects depends on various correlations between species. Genetic correlations are analogous to linkage disequilibrium in standard Mendelian genetics. Correlations in reproductive success between symbiotic partners arise from codispersal and reproductive synchrony. The third topic concerns the evolution of asymmetrical symbioses in which one species can dominate its partner. Dominance may explain the evolution of uniparental inheritance among cytoplasmic symbionts and a peculiar form of germ-soma separation in the symbionts of insects.}, } @article {pmid18811311, year = {1997}, author = {Reeve, HK and Keller, L}, title = {Reproductive bribing and policing as evolutionary mechanisms for the suppression of within-group selfishness.}, journal = {The American naturalist}, volume = {150 Suppl 1}, number = {}, pages = {S42-58}, doi = {10.1086/286049}, pmid = {18811311}, issn = {0003-0147}, abstract = {We show that a new, simple, and robust general mechanism for the social suppression of within-group selfishness follows from Hamilton's rule applied in a multilevel selection approach to asymmetrical, two-person groups: If it pays a group member to behave selfishly (i.e., increase its share of the group's reproduction, at the expense of group productivity), then its partner will virtually always be favored to provide a reproductive "bribe" sufficient to remove the incentive for the selfish behavior. The magnitude of the bribe will vary directly with the number of offspring (or other close kin) potentially gained by the selfish individual and inversely with both the relatedness r between the interactants and the loss in group productivity because of selfishness. This bribe principle greatly extends the scope for cooperation within groups. Reproductive bribing is more likely to be favored over social policing for dominants rather than subordinates and as intragroup relatedness increases. Finally, analysis of the difference between the group optimum for an individual's behavior and the individual's inclusive fitness optimum reveals a paradoxical feedback loop by which bribing and policing, while nullifying particular selfish acts, automatically widen the separation of individual and group optima for other behaviors (i.e., resolution of one conflict intensifies others).}, } @article {pmid18811308, year = {1997}, author = {Boehm, C}, title = {Impact of the human egalitarian syndrome on darwinian selection mechanics.}, journal = {The American naturalist}, volume = {150 Suppl 1}, number = {}, pages = {S100-21}, doi = {10.1086/286052}, pmid = {18811308}, issn = {0003-0147}, abstract = {With nothing more than kin selection and reciprocal altruism theories to work with, the selection basis of human degrees of altruism and cooperation is often difficult to explain. However, during our prehistoric foraging phase, a highly stable egalitarian syndrome arose that had profound effects on Darwinian selection mechanics. The band's insistence on egalitarianism seriously damped male status rivalry and thereby reduced the intensity of selection within the group by reducing phenotypic variation at that level, while powerful social pressure to make decisions consensual at the band level had a similar effect. Consensual decisions also had another effect: they increased variation between groups because entire bands enacted their subsistence strategies collectively and the strategies varied between bands. By reducing the intensity of individual selection and boosting group effects, these behaviors provided a unique opportunity for altruistic genes to be established and maintained. In addition, the egalitarian custom of socially isolating or actively punishing lazy or cheating noncooperators reduced the free-rider problem. In combination, these phenotypic effects facilitated selection of altruistic genes in spite of some limited free riding. This selection scenario remained in place for thousands of generations, and the result was a shift in the balance of power between individual and group selection in favor of group effects. This new balance today is reflected in an ambivalent human nature that exhibits substantial altruism in addition to selfishness and nepotism.}, } @article {pmid9099004, year = {1997}, author = {Hwang, JM and Hofstetter, JR and Bonhomme, F and Karn, RC}, title = {The microevolution of mouse salivary androgen-binding protein (ABP) paralleled subspeciation of Mus musculus.}, journal = {The Journal of heredity}, volume = {88}, number = {2}, pages = {93-97}, doi = {10.1093/oxfordjournals.jhered.a023083}, pmid = {9099004}, issn = {0022-1503}, mesh = {Alleles ; Amino Acid Sequence ; Androgen-Binding Protein/*genetics ; Animals ; Base Sequence ; DNA, Complementary ; *Evolution, Molecular ; Male ; Mice ; Mice, Inbred C3H ; Mice, Inbred DBA ; Molecular Sequence Data ; Phylogeny ; Salivary Proteins and Peptides/*genetics ; }, abstract = {Mouse salivary androgen-binding protein (ABP) is a major secretory product of the submaxillary glands. Although it is a common salivary protein among rodents generally, the function of ABP has yet to be determined. Here we report a comparison of the DNA coding sequences and putative amino acid sequences they determine for the three common alleles of the Alpha subunit gene (Abpa), alleles that appear to be diagnostic for the three subspecies of Mus musculus. Three other unique sequences were found in the species M. caroli, M. spretus, and M. spicilegus. Comparison of the six sequences shows that 8 of the 20 base substitution sites produce a high degree of variability in amino acids 32, 33, 36, and 39, a variability that creates unique sequence combinations in each species and subspecies. We compare the possibilities that selection or genetic drift caused this unusual microevolution and argue that selection is the more likely explanation. We speculate on the potential significance of this with respect to the proposal that ABP is involved in assortive mate kin selection.}, } @article {pmid9025312, year = {1996}, author = {Prodöhl, PA and Loughry, WJ and McDonough, CM and Nelson, WS and Avise, JC}, title = {Molecular documentation of polyembryony and the micro-spatial dispersion of clonal sibships in the nine-banded armadillo, Dasypus novemcinctus.}, journal = {Proceedings. Biological sciences}, volume = {263}, number = {1377}, pages = {1643-1649}, doi = {10.1098/rspb.1996.0240}, pmid = {9025312}, issn = {0962-8452}, mesh = {Alleles ; Animals ; Armadillos/*embryology/*genetics ; Base Sequence ; Biological Evolution ; DNA Primers/genetics ; Female ; Genetic Markers ; Male ; Microsatellite Repeats ; Polymerase Chain Reaction ; Pregnancy ; }, abstract = {A battery of allelic markers at highly polymorphic microsatellite loci was developed and employed to confirm genetically, the clonal nature of sibships in nine-banded armadillos. This phenomenon of consistent polyembryony, otherwise nearly unknown among the vertebrates, was capitalized upon to describe the micro-spatial distributions of numerous clonal sibships in a natural population of armadillos. Adult clone mates were significantly more dispersed than were juvenile sibs, suggesting limited opportunities for altruistic behavioural interactions among mature individuals. These results, and considerations of armadillo natural history, suggest that evolutionary explanations for polyembryony in this species may not reside in the kinds of ecological and kin selection theories relevant to some of the polyembryonic invertebrates. Rather, polyembryony in armadillos may be associated evolutionarily with other reproductive peculiarities of the species, including delayed uterine implantation of a single egg.}, } @article {pmid8962106, year = {1996}, author = {Rodríguez-Gironés, MA and Cotton, PA and Kacelnik, A}, title = {The evolution of begging: signaling and sibling competition.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {93}, number = {25}, pages = {14637-14641}, pmid = {8962106}, issn = {0027-8424}, mesh = {*Animal Communication ; Animals ; *Biological Evolution ; Humans ; *Models, Theoretical ; Sibling Relations ; }, abstract = {In many species, young solicit food from their parents, which respond by feeding them. Because of the difference in genetic make-up between parents and their offspring and the consequent conflict, this interaction is often studied as a paradigm for the evolution of communication. Existent theoretical models demonstrate that chick signaling and parent responding can be stable if solicitation is a costly signal. The marginal cost of producing stronger signals allows the system to converge to an equilibrium: young beg with intensity that reflects their need, and parents use this information to maximize their own inclusive fitness. However, we show that there is another equilibrium where chicks do not beg and parents' provisioning effort is optimal with respect to the statistically probable distribution of chicks' states. Expected fitness for parents and offspring at the nonsignaling equilibrium is higher than at the signaling equilibrium. Because nonsignaling is stable and it is likely to be the ancestral condition, we would like to know how natural systems evolved from nonsignaling to signaling. We suggest that begging may have evolved through direct sibling fighting before the establishment of a parental response, that is, that nonsignaling squabbling leads to signaling. In multiple-offspring broods, young following a condition-dependent strategy in the contest for resources provide information about their condition. Parents can use this information even though it is not an adaptation for communication, and evolution will lead the system to the signaling equilibrium. This interpretation implies that signaling evolved in multiple-offspring broods, but given that signaling is evolutionarily stable, it would also be favored in species which secondarily evolved single-chick broods.}, } @article {pmid8875943, year = {1996}, author = {Sundstrom, L and Chapuisat, M and Keller, L}, title = {Conditional Manipulation of Sex Ratios by Ant Workers: A Test of Kin Selection Theory.}, journal = {Science (New York, N.Y.)}, volume = {274}, number = {5289}, pages = {993-995}, doi = {10.1126/science.274.5289.993}, pmid = {8875943}, issn = {1095-9203}, abstract = {Variable queen mating frequencies provide a unique opportunity to study the resolution of worker-queen conflict over sex ratio in social Hymenoptera, because the conflict is maximal in colonies headed by a singly mated queen and is weak or nonexistent in colonies headed by a multiply mated queen. In the wood ant Formica exsecta, workers in colonies with a singly mated queen, but not those in colonies with a multiply mated queen, altered the sex ratio of queen-laid eggs by eliminating males to preferentially raise queens. By this conditional response to queen mating frequency, workers enhance their inclusive fitness.}, } @article {pmid8794560, year = {1996}, author = {Paxton, RJ and Thorén, PA and Tengö, J and Estoup, A and Pamilo, P}, title = {Mating structure and nestmate relatedness in a communal bee, Andrena jacobi (Hymenoptera, Andrenidae), using microsatellites.}, journal = {Molecular ecology}, volume = {5}, number = {4}, pages = {511-519}, doi = {10.1111/j.1365-294x.1996.tb00343.x}, pmid = {8794560}, issn = {0962-1083}, mesh = {Animals ; Base Sequence ; Bees/*genetics/physiology ; Female ; Gene Frequency ; Heterozygote ; Inbreeding ; Microsatellite Repeats/*genetics ; Molecular Sequence Data ; *Nesting Behavior ; *Sexual Behavior, Animal ; }, abstract = {Complex eusocial insect societies are generally matrifilial, suggesting kin selection has been of importance in their development. For simpler social systems, factors favouring their existence, in particular kin selection, have rarely been studied. Communal nesting is one of these simple social organizations, and is found in a diversity of insect species. To examine whether kin selection may play a role in the evolution and maintenance of communality, we estimated genetic relatedness of nestmate females of the facultatively communal bee, Andrena jacobi. Microsatellite loci were developed for this species and used to analyse individuals from two populations. Loci were variable, they were in heterozygote deficit and showed positive inbreeding coefficients. This may arise from nonrandom mating; previous observations (Paxton & Tengö 1996) indicate that a large proportion of females mate intranidally with nestmate males in their natal nests before first emerging. Nestmate relatedness was low, no different from zero for all loci in one population and for three of four loci in the other population. The large number of nestmates sharing a common nest (up to 594) may explain the low relatedness estimates, although relatedness was also independent of the number of females sharing a nest. Lack of inclusive fitness payoffs could constrain social evolution in this communal species.}, } @article {pmid8760310, year = {1996}, author = {Lefcort, H and Durden, LA}, title = {The effect of infection with Lyme disease spirochetes (Borrelia burgdorferi) on the phototaxis, activity, and questing height of the tick vector Ixodes scapularis.}, journal = {Parasitology}, volume = {113 (Pt 2)}, number = {}, pages = {97-103}, doi = {10.1017/s0031182000066336}, pmid = {8760310}, issn = {0031-1820}, support = {AI24899/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Arachnid Vectors/*microbiology/physiology ; Behavior, Animal ; Borrelia burgdorferi Group/*physiology ; Ixodes/*microbiology/physiology ; Light ; Motor Activity ; Nymph/microbiology/physiology ; }, abstract = {Little is known about the effects of infection with Borrelia burgdorferi, the bacterium that causes Lyme disease, on its tick vectors. The purpose of this study was to determine the behavioural and ecological effects of infection by the bacterium in nymphal and adult black-legged (Ixodes scapularis) ticks. We found that the effects of infection were more pronounced in adults than in nymphs. Compared to uninfected adults, infected adults were less able to overcome physical obstacles, avoided vertical surfaces, were less active and quested at lower heights. Infected nymphs showed increased phototaxis and attraction to vertical surfaces. Infected nymphs also showed trends toward increased questing height and a greater tendency to overcome physical obstacles although these trends were not statistically significant. These altered behaviours in an infected tick may affect survival or pathogen transmission and may reflect kin selection in the bacterial pathogen.}, } @article {pmid8763356, year = {1996}, author = {Taylor, PD and Frank, SA}, title = {How to make a kin selection model.}, journal = {Journal of theoretical biology}, volume = {180}, number = {1}, pages = {27-37}, doi = {10.1006/jtbi.1996.0075}, pmid = {8763356}, issn = {0022-5193}, support = {GM42403/GM/NIGMS NIH HHS/United States ; }, mesh = {Age Factors ; Animals ; *Biological Evolution ; Female ; Male ; Models, Biological ; Sex Ratio ; Social Behavior ; }, abstract = {Kin selection arguments, based on Hamilton's (1964) concept of inclusive fitness, provide a powerful heuristic and can therefore give us valuable insights into the different pathways through which natural selection acts. But their formulation can be quite tricky, requiring as they do, a close accounting of all the fitness effects of a particular item of behaviour. Here we propose a "direct fitness" formulation of inclusive fitness which often has a more straightforward derivation. Our method finds ESS trait values by the standard optimization techniques of simple differentiation plus two additional steps. First, slopes of group phenotype on individual genotype arise naturally during differentiation, and these slopes are replaced by coefficients of relatedness. Second, when behaviours influence different classes such as age, sex of recipient, or other life history components of fitness, the fitness effects on each component are weighted by reproductive value. We illustrate this technique first in a homogeneous population, with examples of group competition and partial dispersal behaviour, and then in a class-structured population, with examples of sex allocation and altruism between age classes.}, } @article {pmid8919665, year = {1996}, author = {Frank, SA}, title = {Models of parasite virulence.}, journal = {The Quarterly review of biology}, volume = {71}, number = {1}, pages = {37-78}, doi = {10.1086/419267}, pmid = {8919665}, issn = {0033-5770}, support = {GM42403/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Bacteria/pathogenicity/virology ; Biological Evolution ; Cross Infection/transmission ; Disease Outbreaks ; Ecosystem ; Escherichia coli Infections/transmission ; Host-Parasite Interactions ; Humans ; *Models, Biological ; Nematoda/pathogenicity ; Parasites/genetics/*pathogenicity ; Parasitic Diseases/parasitology/transmission ; Virulence ; }, abstract = {Several evolutionary processes influence virulence, the amount of damage a parasite causes to its host. For example, parasites are favored to exploit their hosts prudently to prolong infection and avoid killing the host. Parasites also need to use some host resources to reproduce and transmit infections to new hosts. Thus parasites face a tradeoff between prudent exploitation and rapid reproduction-a life history tradeoff between longevity and fecundity. Other tradeoffs among components of parasite fitness also influence virulence. For example, competition among parasite genotypes favors rapid growth to achieve greater relative success within the host. Rapid growth may, however, lower the total productivity of the local group by overexploiting the host, which is a potentially renewable food supply. This is a problem of kin selection and group selection. I summarize models of parasite virulence with the theoretical tools of life history analysis, kin selection, and epidemiology. I then apply the theory to recent empirical studies and models of virulence. These applications, to nematodes, to the extreme virulence of hospital epidemics, and to bacterial meningitis, show the power of simple life history theory to highlight interesting questions and to provide a rich array of hypotheses. These examples also show the kinds of conceptual mistakes that commonly arise when only a few components of parasite fitness are analysed in isolation. The last part of the article connects standard models of parasite virulence to diverse topics, such as the virulence of bacterial plasmids, the evolution of genomes, and the processes that influenced conflict and cooperation among the earliest replicators near the origin of life.}, } @article {pmid8666414, year = {1996}, author = {Guo, SW}, title = {Variation in genetic identity among relatives.}, journal = {Human heredity}, volume = {46}, number = {2}, pages = {61-70}, doi = {10.1159/000154328}, pmid = {8666414}, issn = {0001-5652}, support = {P30 HG00209/HG/NHGRI NIH HHS/United States ; R29 GM52205/GM/NIGMS NIH HHS/United States ; }, mesh = {Analysis of Variance ; *Family ; Gametogenesis ; *Genetic Variation ; Humans ; Models, Genetic ; }, abstract = {Genetic identity, or genetic relatedness, among relatives, is a key concept in kin recognition, which in turn is important in models for inclusive fitness and inbreeding avoidance. A mathematical definition is presented for the genetic identity based on the proportion of genome shared identical by descent by two relatives. The method of Guo [Am J Hum Genet 1995;56:1468-1476] is used to compute the variance of the genetic identity for various types of relationships. The method is versatile and can handle any kind of relationship. To illustrate the method, the standard errors of the genetic identity using published human genetic maps are computed.}, } @article {pmid8924637, year = {1996}, author = {Oliphant, M}, title = {The dilemma of Saussurean communication.}, journal = {Bio Systems}, volume = {37}, number = {1-2}, pages = {31-38}, doi = {10.1016/0303-2647(95)01543-4}, pmid = {8924637}, issn = {0303-2647}, mesh = {Algorithms ; Altruism ; Animals ; Biological Evolution ; *Communication ; Computer Simulation ; *Game Theory ; Humans ; Models, Genetic ; Selection, Genetic ; }, abstract = {A Saussurean communication system exists when an entire communicating population uses a single 'language' that maps states unambiguously onto symbols and then back into the original states. This paper describes a number of simulations performed with a genetic algorithm to investigate the conditions necessary for such communication systems to evolve. The first simulation shows that Saussurean communication evolves in the simple case where direct selective pressure is placed on individuals to be both good transmitters and good receivers. The second simulation demonstrates that, in the more realistic case where selective pressure is only placed on doing well as a receiver, Saussurean communication fails to evolve. Two methods, inspired by research on the Prisoner's Dilemma, are used to attempt to solve this problem. The third simulation shows that, even in the absence of selective pressure on transmission, Saussurean communication can evolve if individuals interact multiple times with the same communication partner and are given the ability to respond differentially based on past interaction. In the fourth simulation, spatially organized populations are used, and it is shown that this allows Saussurean communication to evolve through kin selection.}, } @article {pmid8819816, year = {1996}, author = {Mesterton-Gibbons, M}, title = {On the war of attrition and other games among kin.}, journal = {Journal of mathematical biology}, volume = {34}, number = {3}, pages = {253-260}, pmid = {8819816}, issn = {0303-6812}, mesh = {Animals ; Biological Evolution ; Conflict, Psychological ; Family ; *Game Theory ; Humans ; *Mathematics ; *Models, Psychological ; *Social Behavior ; }, abstract = {Evolutionarily stable strategies or ESSs of games among kin have been calculated in the literature by both "personal-fitness" and "inclusive-fitness" methods. These methods were compared by Hines and Maynard Smith (1979) for games with bilinear payoffs. Although Hines and Maynard Smith regarded the first method as correct, they regarded the second method as useful because the inclusive-fitness conditions for an ESS gave necessary conditions for a personal-fitness ESS in the class of games they considered. In general, however, satisfying the inclusive-fitness conditions is neither necessary nor sufficient for satisfying the inclusive-fitness conditions, although the two methods may often yield identical ESSs. This result is established by reformulating the classic war-of-attrition model to allow variation in energy reserves, assumed to have a Gamma distribution. For this game, the two methods may disagree for intermediate values of relatedness. By the correct method, if the coefficient of variation in energy reserves is sufficiently high, then the game has a unique ESS in pure strategies at which populations with higher coefficients of variation or relatedness display for shorter times. Unrelated contestants are prepared to expend at least half of their reserves. For populations with lower variation coefficients, the ESS exists only if the cost of displaying per unit time is low compared to the rate at which remaining reserves translate into expected future reproductive success for the victor. The critical variation coefficient, below which the ESS exists regardless of cost, decreases from 0.52 to 0 as the coefficient of relatedness increases from 0 to 1. Although there is no assessment, contests are always won by the animal with greater energy reserves in a population at the ESS.}, } @article {pmid8691088, year = {1996}, author = {Taylor, PD}, title = {Inclusive fitness arguments in genetic models of behaviour.}, journal = {Journal of mathematical biology}, volume = {34}, number = {5-6}, pages = {654-674}, pmid = {8691088}, issn = {0303-6812}, mesh = {Alleles ; Animals ; Bees ; Female ; *Genetics, Behavioral ; Male ; *Mathematics ; *Models, Genetic ; *Models, Psychological ; Mutation ; Sex Ratio ; }, abstract = {My purpose here is to provide a coherent account of inclusive fitness techniques, accessible to a mathematically literate graduate student in evolutionary biology, and to relate these to standard one-locus genetic models. I begin in Sect. 2 with a general formulation of evolutionary stability; in Sect. 3 and Sect. 4 I interpret the basic stability conditions within genetic and inclusive fitness models. In Sect. 5 I extend these concepts to the case of a class-structured population, and in Sect. 6 I illustrate these notions with a sex ratio example. In Sect. 7 I give a proof of the result that under additive gene action and weak selection, an inclusive fitness argument is able to verify an important stability condition (2.5) for one-locus genetic models. Most of these results have been published.}, } @article {pmid7566147, year = {1995}, author = {Frank, SA}, title = {Mutual policing and repression of competition in the evolution of cooperative groups.}, journal = {Nature}, volume = {377}, number = {6549}, pages = {520-522}, doi = {10.1038/377520a0}, pmid = {7566147}, issn = {0028-0836}, mesh = {*Biological Evolution ; *Competitive Behavior ; *Cooperative Behavior ; Models, Biological ; Reproduction ; }, abstract = {Evolutionary theory has not explained how competition among lower level units is suppressed in the formation of higher-level evolutionary units. For example, the key problem of early evolution is small, individual replicators formed cooperative groups of sufficient complexity to allow accurate copying of the genetic material. The puzzle is why parasites did not subvert the formation of cells by obtaining benefits from the group without contributing to shared traits that enhance reproduction. These parasites would outcompete other replicators within the cell, disrupting reproductive fairness among subunits and destroying the functional coherence of the group. A similar problem arose at a later evolutionary stage with the orderly mendelian segregation of subunits (chromosomes) within cells, and reproductive fairness continued to be a problem in the evolution of insect and human societies. Here I present a simple model to show how reproductive fairness evolves among subunits to create functional coherence and higher-level units. Self-restraint, which evolves according to the kin-selection coefficient of relatedness, is not sufficient: mutual policing and enforcement of reproductive fairness are also required for the evolution of increasing social complexity.}, } @article {pmid21237086, year = {1995}, author = {Dominguez, CA}, title = {Genetic conflicts of interest in plants.}, journal = {Trends in ecology & evolution}, volume = {10}, number = {10}, pages = {412-416}, doi = {10.1016/s0169-5347(00)89158-2}, pmid = {21237086}, issn = {0169-5347}, abstract = {Several features of the reproductive biology of seed plants have recently been explained using kin-selection interpretations. The simultaneous presence of tissues with different genetic make-ups during several phases of a seed-plant's life cycle is a feature that sets the conditions for agonistic interactions among selfish genes. The available empirical evidence indicates that genetic conflicts of interest are prevalent phenomena in seed plants. Recent research on the patterns of endosperm gene transmission provides a framework for new interpretations of the role of inclusive fitness in plants.}, } @article {pmid21237068, year = {1995}, author = {Keller, L}, title = {Social life: the paradox of multiple-queen colonies.}, journal = {Trends in ecology & evolution}, volume = {10}, number = {9}, pages = {355-360}, doi = {10.1016/s0169-5347(00)89133-8}, pmid = {21237068}, issn = {0169-5347}, abstract = {The evolution of animal societies in which some individuals forego their own reproductive opportunities to help others to reproduce poses an evolutionary paradox that can be traced to Darwin. Altruism may evolve through kin selection when the donor and recipient of altruistic acts are related to each other, as generally is the case in social birds and mammals. Similarly, social insect workers are highly related to the brood they rear when colonies are headed by a single queen. However, recent studies have shown that insect colonies frequently contain several queens, with the effect of decreasing relatedness among colony members. How can one account for the origin and maintenance of such colonies? This evolutionary enigma presents many of the same theoretical challenges as does the evolution of cooperative breeding and eusociality.}, } @article {pmid7667250, year = {1995}, author = {Emlen, ST}, title = {An evolutionary theory of the family.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {92}, number = {18}, pages = {8092-8099}, pmid = {7667250}, issn = {0027-8424}, mesh = {Animals ; *Biological Evolution ; *Family ; Female ; Humans ; Male ; Reproduction ; }, abstract = {An evolutionary framework for viewing the formation, the stability, the organizational structure, and the social dynamics of biological families is developed. This framework is based upon three conceptual pillars: ecological constraints theory, inclusive fitness theory, and reproductive skew theory. I offer a set of 15 predictions pertaining to living within family groups. The logic of each is discussed, and empirical evidence from family-living vertebrates is summarized. I argue that knowledge of four basic parameters, (i) genetic relatedness, (ii) social dominance, (iii) the benefits of group living, and (iv) the probable success of independent reproduction, can explain many aspects of family life in birds and mammals. I suggest that this evolutionary perspective will provide insights into understanding human family systems as well.}, } @article {pmid11607532, year = {1995}, author = {Friedman, WE}, title = {Organismal duplication, inclusive fitness theory, and altruism: understanding the evolution of endosperm and the angiosperm reproductive syndrome.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {92}, number = {9}, pages = {3913-3917}, pmid = {11607532}, issn = {0027-8424}, abstract = {For almost a century, events relating to the evolutionary origin of endosperm, a unique embryo-nourishing tissue that is essential to the reproductive process in flowering plants, have remained a mystery. Integration of recent advances in phylogenetic reconstruction, comparative reproductive biology, and genetic theory can be used to elucidate the evolutionary events and forces associated with the establishment of endosperm. Endosperm is shown to be derived from one of two embryos formed during a rudimentary process of "double fertilization" that evolved in the ancestors of angiosperms. Acquisition of embryo-nourishing behavior (with accompanying loss of individual fitness) by this supernumerary fertilization product was dependent upon compensatory gains in the inclusive fitness of related embryos. The result of the loss of individual fitness by one of the two original products of double fertilization was the establishment of endosperm, a highly modified embryo/organism that reproduces cryptically through behavior that enhances the fitness of its associated embryo within a seed. Finally, although triploid endosperm remains a synapomorphy of angiosperms, inclusive fitness analysis demonstrates that the embryo-nourishing properties of endosperm initially evolved in a diploid condition.}, } @article {pmid7560919, year = {1995}, author = {Dickemann, M}, title = {Wilson's Panchreston: the inclusive fitness hypothesis of sociobiology re-examined.}, journal = {Journal of homosexuality}, volume = {28}, number = {1-2}, pages = {147-183}, doi = {10.1300/J082v28n01_09}, pmid = {7560919}, issn = {0091-8369}, mesh = {Animals ; Female ; *Gender Identity ; Gene Frequency ; Genotype ; Homosexuality/*genetics/psychology ; Humans ; Male ; Phenotype ; Reproduction/genetics ; Selection, Genetic ; *Sex ; Sexual Behavior ; Social Environment ; }, abstract = {Of several hypotheses proposed by sociobiologists to explain "homosexuality", the most widely discussed is the inclusive fitness hypothesis, which is examined here in the work of the primary sociobiological proponents, E. O. Wilson, Michael Ruse, and James Weinrich. After reviewing the basic evolutionary concepts of natural selection, adaptation, and inclusive fitness/kin selection, I analyze the inclusive fitness hypotheses of homosexuality, taking as an exemplar the initial statement of E. O. Wilson. The implicit assumptions is this hypothesis are identified: that "homosexuality" is a unitary phenomenon, of direct genetic origin, occurring at similar frequencies across societies and through time, without direct reproductive gain, with therefore must be of genetic advantage to relatives. Each of these implicit assumptions is discussed and assessed in turn. The inclusive fitness hypothesis, derived primarily from current stereotypes about homosexuals in Western society, is found to be misconceived and without scientific merit. A general discussion of the nature-nurture, or essentialist-social-constructionist, controversy as it involves this hypothesis concludes the essay.}, } @article {pmid7838853, year = {1994}, author = {Frank, SA}, title = {Kin selection and virulence in the evolution of protocells and parasites.}, journal = {Proceedings. Biological sciences}, volume = {258}, number = {1352}, pages = {153-161}, doi = {10.1098/rspb.1994.0156}, pmid = {7838853}, issn = {0962-8452}, support = {GM42403/GM/NIGMS NIH HHS/United States ; S07-RR07008/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Host-Parasite Interactions ; Larva/parasitology ; Models, Biological ; Virulence ; Wasps/*parasitology ; }, abstract = {The evolution of parasite virulence and the origin of cooperative genomes in primitive cells are both problems that balance cooperative and competitive interactions among symbionts. I analyse the trade-off among three correlated traits: competitiveness against other genotypes for resources within hosts (protocells), damage to the host (virulence), and rate of horizontal transmission from one host to another. All three life-history components are strongly influenced by kin selection. For example, when genetic relatedness within hosts is high, each genotype is competing for resources with closely related genotypes. This competition among relatives favours increased horizontal transmission to colonize new hosts and compete against non-relatives. My analysis shows that many aspects of parasite and protocell evolution must be studied with the theoretical tools of social evolution. I discuss extensions that are required for a general theory of symbiosis.}, } @article {pmid7973654, year = {1994}, author = {McDonald, DB and Potts, WK}, title = {Cooperative display and relatedness among males in a lek-mating bird.}, journal = {Science (New York, N.Y.)}, volume = {266}, number = {5187}, pages = {1030-1032}, doi = {10.1126/science.7973654}, pmid = {7973654}, issn = {0036-8075}, mesh = {Alleles ; Animals ; Base Sequence ; Birds/genetics/*physiology ; *Cooperative Behavior ; Copulation ; Female ; Heterozygote ; Male ; Molecular Sequence Data ; Polymerase Chain Reaction ; *Sexual Behavior, Animal ; }, abstract = {Long-tailed manakins mate in leks and cooperate in multiyear male-male partnerships. An alpha male is responsible for virtually all mating, whereas a beta male assists in the courtship displays. Such altruism by the beta male poses a problem for evolutionary theory because most theoretical treatments and empirical examples of cooperative behavior involve kin selection or reciprocity. Here it is shown that alpha and beta partners are not relatives and that reciprocity is not involved. Instead, direct, though long-delayed benefits to beta males are demonstrated, which include rare copulations, ascension to alpha status, and female lek fidelity. These benefits maintain this unusual form of male-male cooperation.}, } @article {pmid7872929, year = {1994}, author = {D'Amato, FR}, title = {Physiological evidence for genetically mediated sibling recognition in mice.}, journal = {Behavior genetics}, volume = {24}, number = {6}, pages = {493-496}, pmid = {7872929}, issn = {0001-8244}, mesh = {Animals ; Arousal/*genetics/physiology ; Male ; Mice/*genetics/physiology ; Opioid Peptides/genetics/physiology ; Pain Threshold/physiology ; *Phenotype ; *Sibling Relations ; *Social Behavior ; Social Environment ; }, abstract = {The kin selection theory predicts that individuals would behave differently toward one another, depending on their genetic relatedness. Kin discrimination has been demonstrated in mice from social behavior, and previous familiarity, as well as familiarity with the partner's phenotype, has been postulated to represent proximate mechanisms. It has already been demonstrated that siblings' reunion resulted in a decrease in pain sensitivity that is mediated by endogenous opioids. In this study, using a cross-transferring design, it is shown that genetic relatedness with the male partner, independently of postnatal association, is responsible for changes in nociceptive threshold. Conversely, previous association till weaning has no effect on pain sensitivity. These data suggest that endogenous opioids activity and social behavior represent indices of different processes: the recognition of related animals and the discrimination of familiar (and also usually related) subjects, respectively.}, } @article {pmid7996864, year = {1994}, author = {Frank, SA}, title = {Genetics of mutualism: the evolution of altruism between species.}, journal = {Journal of theoretical biology}, volume = {170}, number = {4}, pages = {393-400}, doi = {10.1006/jtbi.1994.1200}, pmid = {7996864}, issn = {0022-5193}, support = {GM42403/GM/NIGMS NIH HHS/United States ; S07-RR07008/RR/NCRR NIH HHS/United States ; }, mesh = {*Altruism ; Animals ; *Biological Evolution ; *Models, Genetic ; Selection, Genetic ; Symbiosis ; }, abstract = {Conditions are analyzed under which natural selection favors an individual to help another species at a cost to its own reproduction. Traditional models for the evolution of altruism between species focus on the genetic relatedness between the original donor and the recipients of return benefits from the mutualistic partner species. A more general model is analyzed here that focuses on the synergistic effects between partner species caused by genetic variability. The model shows that the spread of altruism is enhanced by spatial correlations between species in the genetic tendency to give aid to partners. These spatial correlations between species are similar to the kin selection coefficients of relatedness that determine the course of social evolution within species. The model also shows that natural selection and ecological dynamics can create genetic correlations between neighbors of different species, even when the initial spatial distributions of the species are uncorrelated. Genetic correlations between species may play an important role in the origin and maintenance of altruism between species.}, } @article {pmid7967638, year = {1994}, author = {Leibowitz, AH}, title = {Selection for hybrid inviability through kin selection.}, journal = {Journal of theoretical biology}, volume = {170}, number = {2}, pages = {163-174}, doi = {10.1006/jtbi.1994.1176}, pmid = {7967638}, issn = {0022-5193}, mesh = {Animals ; *Biological Evolution ; Fertility/genetics ; *Genes ; *Hybrid Vigor ; *Models, Genetic ; *Selection, Genetic ; Sexual Behavior, Animal ; }, abstract = {A model is considered in which a modifier allele that decreases the fitness of partially sterile hybrids is favoured by natural selection. Such genes can be favoured if there is sib competition and hybrid fertility is very low. They can be favoured through a process of kin selection because a reduction of hybrid viability brings about a reduction in the consumption of resources that are therefore available for utilization by non-hybrid siblings who are likely to also carry the gene for hybrid inviability. The present analysis differs from previous studies in that it treats the problem as a specific case of the evolution of altruism and considers the effect of the reduced viability of hybrids on their inclusive fitness. The model is analysed for monogamy and an extreme form of polygamy. In general, hybrid fertility must be lower with polygamy than with monogamy for modifier alleles to be favoured. However, the strength of selection on the modifiers is an order of magnitude greater with polygamy. With polygamy, provided that hybrid fertility is very low, modifier alleles will always be favoured irrespective of the degree of sib competition. However, for monogamy, if the individuals of more than just a few sib-groups compete for resources the modifier cannot be favoured. The effect of sib competition on preventing the spread of genes that increase hybrid viability is also briefly discussed.}, } @article {pmid7915048, year = {1994}, author = {Morin, PA and Moore, JJ and Chakraborty, R and Jin, L and Goodall, J and Woodruff, DS}, title = {Kin selection, social structure, gene flow, and the evolution of chimpanzees.}, journal = {Science (New York, N.Y.)}, volume = {265}, number = {5176}, pages = {1193-1201}, doi = {10.1126/science.7915048}, pmid = {7915048}, issn = {0036-8075}, support = {1T32 HG00005-02/HG/NHGRI NIH HHS/United States ; }, mesh = {Africa ; Alleles ; Animals ; Base Sequence ; *Biological Evolution ; DNA/analysis/genetics ; Female ; *Genetic Variation ; Hair/chemistry ; Male ; Molecular Sequence Data ; Pan troglodytes/classification/*genetics/psychology ; Phylogeny ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Repetitive Sequences, Nucleic Acid ; *Social Behavior ; Tanzania ; }, abstract = {Hypotheses about chimpanzee social behavior, phylogeography, and evolution were evaluated by noninvasive genotyping of free-ranging individuals from 20 African sites. Degrees of relatedness among individuals in one community were inferred from allele-sharing at eight nuclear simple sequence repeat (SSR) loci. Males are related on the order of half-siblings, and homozygosity is significantly increased at several SSR loci compared to Hardy-Weinberg expectations. These data support the kin-selection hypothesis for the evolution of cooperation among males. Sequence variation patterns at two mitochondrial loci indicate historically high long-distance gene flow and clarify the relationships among three allopatric subspecies. The unexpectedly large genetic distance between the western subspecies, Pan troglodytes verus, and the other two subspecies suggests a divergence time of about 1.58 million years. This result, if confirmed at nuclear loci and supported by eco-behavioral data, implies that P. t. verus should be elevated to full species rank.}, } @article {pmid8079196, year = {1994}, author = {Kelly, JK}, title = {The effect of scale dependent processes on kin selection: mating and density regulation.}, journal = {Theoretical population biology}, volume = {46}, number = {1}, pages = {32-57}, doi = {10.1006/tpbi.1994.1018}, pmid = {8079196}, issn = {0040-5809}, mesh = {Animals ; *Biological Evolution ; Cluster Analysis ; Gene Frequency ; Genetic Variation ; Linear Models ; *Models, Biological ; Population Density ; Population Dynamics ; *Selection, Genetic ; *Sexual Behavior, Animal ; }, abstract = {Kin selection models describe fitness determining interactions that occur within small clusters of individuals often referred to as trait groups (Wilson, 1975). Because each individual influences not only its own fitness, but also the fitness of other members of the trait group, kin selection has both inter- and intra-group components (Hamilton, 1975; Wade, 1980). The importance of intergroup selection depends on the magnitude of inter-group differences in fertility and on the amount of genetic variation among trait groups. Migration and density regulation are likely to be important determinants of productivity and variation. Existing models integrate density regulation and migration structure into kin selection theory by applying carrying capacities or migration rates to trait groups. This requires that dispersal and density regulation both operate at the spatial scale of trait groups and excludes many cases of biological interest. I present a model that allows interaction, density regulation, and dispersion to operate over distinct spatial scales. The results of existing models can be retrieved as special cases of the general framework developed here. This model indicates that the appropriate scale for studying kin selection is determined by the spatial area over which the population is regulated. In effect, only a fraction of the total inter-trait group variance is available to intergroup selection. Processes that generate genetic variation over spatial scales larger than the "regulation scale" cannot aid the evolution of altruism. The analysis of a specific mating/migration model indicates how the various components of variation are determined by biological parameters such as migration rate. These results have important implications for the study of relatedness in natural populations.}, } @article {pmid8016752, year = {1994}, author = {Taylor, PD}, title = {Sex ratio in a stepping-stone population with sex-specific dispersal.}, journal = {Theoretical population biology}, volume = {45}, number = {2}, pages = {203-218}, doi = {10.1006/tpbi.1994.1011}, pmid = {8016752}, issn = {0040-5809}, mesh = {Animals ; Female ; Humans ; Male ; *Models, Biological ; Ploidies ; *Population Dynamics ; *Sex Ratio ; *Sexual Behavior, Animal/physiology ; }, abstract = {The theoretical hypothesis that the sex-ratio should be biased towards the sex with the wider and/or more even dispersal pattern is tested and confirmed with an inclusive fitness model in a one-dimensional diploid stepping-stone population in which offspring can remain on their home site or disperse one site to the right or left. Two models are examined, dispersal of both sexes before mating and male dispersal before mating followed by dispersal of mated females.}, } @article {pmid21236784, year = {1994}, author = {Jennions, MD and Macdonald, DW}, title = {Cooperative breeding in mammals.}, journal = {Trends in ecology & evolution}, volume = {9}, number = {3}, pages = {89-93}, doi = {10.1016/0169-5347(94)90202-X}, pmid = {21236784}, issn = {0169-5347}, abstract = {Cooperative breeding in mammals covers a diversity of breeding systems. In all cases, however, Individuals assist in the rearing of offspring other than their own. Recent research has highlighted some of the factors responsible for variation both within and between species. While it is possible to generalize about the selective pressures leading to cooperative breeding, doing so may obscure important contrasts between taxa. Of course, inclusive-fitness models explain the generalities of cooperative breeding, but differences in ecology, physiology and life history may result in distinctive processes operating in different taxa-data only likely to emerge from long-term field studies.}, } @article {pmid21236765, year = {1994}, author = {Jarvis, JU and O'Riain, MJ and Bennett, NC and Sherman, PW}, title = {Mammalian eusociality: a family affair.}, journal = {Trends in ecology & evolution}, volume = {9}, number = {2}, pages = {47-51}, doi = {10.1016/0169-5347(94)90267-4}, pmid = {21236765}, issn = {0169-5347}, abstract = {Comparative studies of two species of mole-rat are helping to clarify the ecological correlates of mammalian eusociality. Both species live in social groups composed of close kin, within which breeding is restricted to one female and one to three males. They inhabit xeric areas with dispersed, patchy food and unpredictable rainfall. During droughts, they can neither expand their tunnel systems nor disperse. In brief periods after rain the animals must cooperate and dig furiously to locate rich food patches. By living in groups, arid-zone mole-rats can take full advantage of windows of opportunity when conditions are right for burrowing. Thus, ecological factors and kin selection have apparently interacted in the evolution of eusociality in these species.}, } @article {pmid8216163, year = {1993}, author = {D'Amato, FR and Pavone, F}, title = {Endogenous opioids: a proximate reward mechanism for kin selection?.}, journal = {Behavioral and neural biology}, volume = {60}, number = {1}, pages = {79-83}, doi = {10.1016/0163-1047(93)90768-d}, pmid = {8216163}, issn = {0163-1047}, mesh = {Animals ; Behavior, Animal/drug effects ; Brain/*metabolism ; *Emotions ; Male ; Naloxone/*pharmacology ; Narcotics/*metabolism ; Pain ; Rats ; Reinforcement, Psychology ; Sibling Relations ; }, abstract = {The kin selection theory predicts that individuals would behave differently toward one another, depending on their genetic relatedness. Proximate mechanisms have been postulated to exist helping the individual to discriminate what is good or bad for him. Opioids have been discovered to be involved in the mediation of reinforcement, in particular they underlay social emotion. In this study it is shown that pain sensitivity decreased in male mice interacting with siblings following 2 months of separation; this analgesic response was antagonized by naloxone administration. Interaction with unknown and unrelated subjects did not change the nociceptive threshold. These results suggest that interacting with kin is an adaptive situation reinforced, at the neural level, by the release of endogenous opioids.}, } @article {pmid8480176, year = {1993}, author = {Amos, B and Schlötterer, C and Tautz, D}, title = {Social structure of pilot whales revealed by analytical DNA profiling.}, journal = {Science (New York, N.Y.)}, volume = {260}, number = {5108}, pages = {670-672}, doi = {10.1126/science.8480176}, pmid = {8480176}, issn = {0036-8075}, mesh = {Alleles ; Animals ; Base Sequence ; DNA, Satellite/*genetics ; Female ; Genotype ; Male ; Molecular Sequence Data ; Oligodeoxyribonucleotides/genetics ; Repetitive Sequences, Nucleic Acid ; Sexual Behavior, Animal ; *Social Behavior ; Whales/genetics/*physiology ; }, abstract = {Long-finned pilot whales swim in large, extremely cohesive social groups known as pods. Molecular typing revealed that pod members form a single extended family. Mature males neither disperse from nor mate within their natal pods, a situation unusual for mammals. Such behavior could be explained in terms of inclusive fitness benefits gained by adult males helping the large number of female relatives with which they swim.}, } @article {pmid8479520, year = {1993}, author = {Pfennig, DW and Collins, JP}, title = {Kinship affects morphogenesis in cannibalistic salamanders.}, journal = {Nature}, volume = {362}, number = {6423}, pages = {836-838}, doi = {10.1038/362836a0}, pmid = {8479520}, issn = {0028-0836}, mesh = {Animals ; *Cannibalism ; Crosses, Genetic ; Environment ; Inbreeding ; Larva ; Morphogenesis/*genetics ; Random Allocation ; Urodela/*genetics/physiology ; }, abstract = {Inclusive fitness theory predicts that organisms can often increase their fitness by helping relatives. Indeed, many animals modify their behaviour towards kin in a fashion consistent with theory. Morphogenesis may also be sensitive to kinship environment, especially in species that facultatively produce distinct morphs that differ in their ability to harm relatives, such as those that produce alternative cannibalistic and non-cannibalistic phenotypes. We tested this hypothesis by examining whether consanguinity affected the probability that structurally distinctive cannibal morphs would develop in larval Arizona tiger salamanders (Ambystoma tigrinum nebulosum). We report here that when tiger salamander larvae are reared in mixed-brood groups they are significantly more likely to develop the cannibal morphology and at an earlier age than siblings reared in pure-sibship groups. In general, morphogenesis may be responsive to kinship in any species that facultatively develops structures that can be used against conspecifics as weaponry.}, } @article {pmid8434656, year = {1993}, author = {Erickson, MT}, title = {Rethinking Oedipus: an evolutionary perspective of incest avoidance.}, journal = {The American journal of psychiatry}, volume = {150}, number = {3}, pages = {411-416}, doi = {10.1176/ajp.150.3.411}, pmid = {8434656}, issn = {0002-953X}, mesh = {Altruism ; Animals ; Biological Evolution ; Ethology ; *Family ; Female ; Humans ; Incest/prevention & control/*psychology ; Male ; Models, Psychological ; *Object Attachment ; Oedipus Complex ; }, abstract = {The author presents a biological hypothesis of incest avoidance. Pertinent literature from evolutionary biology, ethology, anthropology, and clinical research is reviewed. Secure early bonding to immediate kin predicts later adaptive kin-directed behaviors, including preferential altruism (kin selection) and incest avoidance. Impaired bonding predicts aberrant kin-directed behavior, including diminished altruism, neglect, and an increased incidence of incest. Failed bonding predicts the highest frequency of incest. Secure bonding to kin may function to establish adaptive kin-directed behaviors, including incest avoidance. Bonding is conceived of as the developmental foundation of a form of social attraction, here called "familial attraction," which is evolutionarily distinct from sexual attraction.}, } @article {pmid21236112, year = {1993}, author = {Creel, S}, title = {Why cooperate? Game theory and kin selection.}, journal = {Trends in ecology & evolution}, volume = {8}, number = {2}, pages = {71-72}, doi = {10.1016/0169-5347(93)90164-K}, pmid = {21236112}, issn = {0169-5347}, } @article {pmid12345038, year = {1993}, author = {Otani, K}, title = {[Cohort fertility and the Cigno model].}, journal = {Kansai Daigaku keizai ronshu}, volume = {42}, number = {6}, pages = {165-201}, pmid = {12345038}, issn = {0449-7554}, mesh = {Asia ; *Birth Intervals ; Birth Rate ; *Cohort Studies ; Demography ; Developed Countries ; Economics ; *Educational Status ; *Employment ; *Family Characteristics ; Family Relations ; Asia, Eastern ; *Fertility ; Geography ; Japan ; *Models, Theoretical ; *Nuclear Family ; *Parents ; Population ; Population Dynamics ; Research ; *Residence Characteristics ; Social Class ; Socioeconomic Factors ; }, } @article {pmid8010304, year = {1993}, author = {Jones, OD}, title = {Reproductive autonomy and evolutionary biology: a regulatory framework for trait-selection technologies.}, journal = {American journal of law & medicine}, volume = {19}, number = {3}, pages = {187-231}, pmid = {8010304}, issn = {0098-8588}, mesh = {*Biological Evolution ; Family Planning Services/*legislation & jurisprudence ; Female ; *Genetic Enhancement ; *Genetic Techniques ; *Government Regulation ; Human Rights/*legislation & jurisprudence ; Humans ; Infant, Newborn ; Male ; *Personal Autonomy ; Pregnancy ; *Reproductive Techniques ; *Selection, Genetic ; Sex Preselection ; Social Responsibility ; United States ; }, abstract = {The Constitution protects, in some measure, each person's autonomy in making basic decisions about family, parenthood, and procreation. This Article examines the extent to which courts should protect from government intrusions a parent's access to technologies that influence specific characteristics of offspring. Beginning with Supreme Court opinions that articulate constitutional and social values regarding reproductive autonomy, the Article explores how important new insights from evolutionary biology may supplement an understanding of human procreation. Specifically, the Article explains how trait selection can constitute an important part of larger "reproductive strategies" that powerfully affect an individual's "inclusive fitness" (itself a measure of reproductive success). It concludes that access to trait-selection technologies should receive the same federal protection from government intrusions as that afforded access to abortion. It proposes the first limit to that protection, however, when a parent seeks to select for a trait, or to use a technique, that would be clearly and significantly damaging to the future child. The Article subsequently divides the use of trait-selection technologies (TSTs) into eight contexts and proposes a preliminary framework by which a regulatory system could legitimately distinguish among them.}, } @article {pmid1362989, year = {1992}, author = {Frank, SA}, title = {A kin selection model for the evolution of virulence.}, journal = {Proceedings. Biological sciences}, volume = {250}, number = {1329}, pages = {195-197}, doi = {10.1098/rspb.1992.0149}, pmid = {1362989}, issn = {0962-8452}, support = {BRSG-S07-RR07008/RR/NCRR NIH HHS/United States ; GM42403/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Humans ; Mathematics ; Models, Genetic ; Parasites/*pathogenicity ; Parasitic Diseases/genetics/*immunology ; Virulence/*genetics ; }, abstract = {The costs and benefits of parasite virulence are analysed in an evolutionarily stable strategy (ESS) model. Increased host mortality caused by disease (virulence) reduces a parasite's fitness by damaging its food supply. The fitness costs of high virulence may be offset by the benefits of increased transmission or ability to withstand the host's defences. It has been suggested that multiple infections lead to higher virulence because of competition among parasite strains within a host. A quantitative prediction is given for the ESS virulence rate as a function of the coefficient of relatedness among co-infecting strains. The prediction depends on the quantitative relation between the costs of virulence and the benefits of transmission or avoidance of host defences. The particular mechanisms by which parasites can increase their transmission or avoid host defences also have a key role in the evolution of virulence when there are multiple infections.}, } @article {pmid1296098, year = {1992}, author = {Quenette, PY and Gerard, JF}, title = {Does frequency-dependent selection optimize fitness?.}, journal = {Journal of theoretical biology}, volume = {159}, number = {4}, pages = {381-385}, doi = {10.1016/s0022-5193(05)80684-8}, pmid = {1296098}, issn = {0022-5193}, mesh = {Animals ; *Models, Genetic ; Phenotype ; *Selection, Genetic ; }, abstract = {In evolutionary biology, the axiom that natural selection tends ideally to maximize inclusive fitness of the individual or some other suitable quantity is often advanced (Cody, 1974; Maynard Smith, 1978; Krebs & McCleery, 1984; Houston et al., 1988). Moreover, the evolutionists generally distinguish two situations (Dawkins, 1980; Maynard Smith, 1982): one in which fitness is independent of the frequency of the phenotypes present in the population (frequency-independent selection), and one in which it does depend on this frequency (frequency-dependent selection). This led some authors such as Parker (1984), and more recently Parker & Maynard Smith (1990), to consider "a 2-speed optimization": frequency-independent selection should lead to a "simple optimum" at the end of the selective process, since all the individuals should have the same strategy and the mean fitness of the population should be maximized; frequency-dependent selection, formulated in terms of the theory of games, should lead to a "competitive optimum" even though the "evolutionary stable strategy" (or "ESS"; Maynard Smith & Price, 1973) characterizing the equilibrium "is not the strategy that maximizes fitness in a population sense" (Parker & Maynard Smith, 1990: 30). Our aim in this short communication is to criticize the concept of "competitive optimum" by Parker & Maynard Smith, as well as the general ability of natural selection to "maximize fitness", even in "phenotypic models" (Lloyd, 1977). These models, devoid of genetic constraints since each strategist is assumed to reproduce its own kind, are especially suitable for examining the ideal effect of natural selection.}, } @article {pmid1461279, year = {1992}, author = {Manning, CJ and Wakeland, EK and Potts, WK}, title = {Communal nesting patterns in mice implicate MHC genes in kin recognition.}, journal = {Nature}, volume = {360}, number = {6404}, pages = {581-583}, doi = {10.1038/360581a0}, pmid = {1461279}, issn = {0028-0836}, mesh = {Animals ; *Behavior, Animal ; Discrimination, Psychological ; Female ; *Genotype ; *Major Histocompatibility Complex ; Mice/*genetics ; Mice, Inbred BALB C ; Mice, Inbred C57BL ; Mice, Inbred DBA ; *Nesting Behavior ; Odorants ; Phenotype ; }, abstract = {House mice (Mus musculus domesticus) form communal nests and appear to nurse each other's pups indiscriminately. Communal nesting probably functions to reduce infanticide, but it also makes females vulnerable to exploitation if nursing partners fail to provide their fair share of care. Kinship theory predicts that females will preferentially form communal nests with relatives to minimize exploitation and further increase inclusive fitness. Here we provide evidence from seminatural populations that females prefer communal nesting partners that share allelic forms of major histocompatibility complex genes. Such behaviour would lead to the selection of close relatives as communal nesting partners. Although criteria for the demonstration of kin recognition are currently embroiled in controversy, this is the first vertebrate study to meet Grafen's restrictive requirements: discrimination is based on genetic similarity at highly polymorphic loci, incidental correlations due to relatedness are experimentally controlled, and strong reasons exist for expecting the assayed behaviour to be kin-selected.}, } @article {pmid19426032, year = {1992}, author = {Goodnight, KF}, title = {The effect of stochastic variation on kin selection in a budding-viscous population.}, journal = {The American naturalist}, volume = {140}, number = {6}, pages = {1028-1040}, doi = {10.1086/285454}, pmid = {19426032}, issn = {0003-0147}, abstract = {Recent theoretical work suggests that kin selection cannot operate in a viscous, group-structured population. This view is based on the separation of kin selection dynamics into two components: a within-group component that must always select against an altruist allele and an among-groups component that may favor the allele if the benefit/cost ratio is sufficiently high. The argument is that in a viscous population, the within-group component will dominate, and an altruist allele cannot succeed by kin selection. However, stochastic variation in group composition maintains the among-groups component of kin selection and allows an altruist allele to succeed if it meets the requirements of Hamilton's rule. Computer simulations confirm that in populations with a viscous, permanent group structure, an altruist allele always fails in the absence of stochastic variation but follows Hamilton's rule if realistic levels of random variation are maintained.}, } @article {pmid1485274, year = {1992}, author = {Lessard, S}, title = {Relatedness and inclusive fitness with inbreeding.}, journal = {Theoretical population biology}, volume = {42}, number = {3}, pages = {284-307}, doi = {10.1016/0040-5809(92)90016-m}, pmid = {1485274}, issn = {0040-5809}, mesh = {Animals ; Genetic Variation/*genetics ; Humans ; *Inbreeding ; *Models, Genetic ; Phenotype ; *Selection, Genetic ; }, abstract = {Relatedness arising in kin selection theory is measured by a variable taking as values two pedigree indices in populations with inbreeding when selection is weak. This variable reduces to a single pedigree index when inbreeding is caused by partial selfing or partial sib-mating. General inclusive fitness formulations of kin selection models based on such a variable of relatedness are proposed.}, } @article {pmid21236052, year = {1992}, author = {Queller, DC}, title = {Does population viscosity promote kin selection?.}, journal = {Trends in ecology & evolution}, volume = {7}, number = {10}, pages = {322-324}, doi = {10.1016/0169-5347(92)90120-Z}, pmid = {21236052}, issn = {0169-5347}, } @article {pmid1416099, year = {1992}, author = {Pearson, OP}, title = {Reproduction in a South American mouse, Abrothrix longipilis.}, journal = {The Anatomical record}, volume = {234}, number = {1}, pages = {73-88}, doi = {10.1002/ar.1092340109}, pmid = {1416099}, issn = {0003-276X}, mesh = {Animals ; Body Weight ; Corpus Luteum/anatomy & histology/physiology ; Estrus/physiology ; Female ; Genitalia/anatomy & histology/physiology ; Male ; Muridae/anatomy & histology/*physiology ; Pregnancy ; Reproduction/*physiology ; Seasons ; Sex Characteristics ; Sexual Maturation/physiology ; South America ; }, abstract = {Approximately 700 Abrothrix longipilis were trapped in Argentina, and their reproductive organs were studied. Some were kept briefly in captivity. Males have the same body length as females but are 8% heavier. Sexually immature males are shorter and lighter than breeding males of the same age. Few individuals in the wild live as long as two years. All overwintering males come into breeding condition in the spring and become infertile in the autumn. All overwintering females have open vaginas in the spring, and most undergo several infertile ovulatory cycles, probably without copulating, before they become pregnant. Corpora lutea of the sterile cycles accumulate; there may be as many as 28 in a pair of ovaries. The average number of ova shed per cycle is 4.66; average litter size is 3.85. Ovulation is spontaneous. There is postpartum ovulation and fertilization without intervening sterile cycles but with maintenance of old corpora lutea. Unusual architecture of the penis and vagina may result from unusual timing of hormone production during development, and the disjunction of ovulation and fertilization may similarly result from hormonal heterochrony at the beginning of the breeding season. The apparently nonadaptive wastage of ova in sterile cycles may be a novel example of kin selection.}, } @article {pmid1460875, year = {1992}, author = {Kelly, JK}, title = {Kin selection in density regulated populations.}, journal = {Journal of theoretical biology}, volume = {157}, number = {4}, pages = {447-461}, doi = {10.1016/s0022-5193(05)80663-0}, pmid = {1460875}, issn = {0022-5193}, mesh = {Animals ; *Gene Frequency ; Mathematics ; *Models, Genetic ; Population Density ; Population Dynamics ; *Selection, Genetic ; }, abstract = {The process of kin selection has both intra- and inter-group components (Hamilton, 1975, in: Biosocial Anthropology Wade, 1980). Group advantageous characteristics can evolve when inter-group differences in fertility are sufficiently great to overcome any within-group disadvantage of the trait. The potential magnitude of inter-group differences in fertility is determined largely by the way a population is regulated. Inter-group differences decrease as the spatial scale over which a population is regulated becomes increasingly localized. The present paper extends previous work by Boyd (1982, Anim. Behav. 30, 972-982) on the quantitative relation between kin selection and density regulation. A simple genetic model is employed to examine the conditions under which the interaction of local density regulation and kin selection can maintain a stable polymorphism. The ecological factors determining the spatial and temporal scale of density regulation are discussed. Finally, the results are applied to two biological cases in which local density regulation may be influencing the direction of phenotypic plasticity in group advantageous characters.}, } @article {pmid1763014, year = {1991}, author = {Gadagkar, R}, title = {Demographic predisposition to the evolution of eusociality: a hierarchy of models.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {88}, number = {24}, pages = {10993-10997}, pmid = {1763014}, issn = {0027-8424}, mesh = {Animals ; *Biological Evolution ; Demography ; Mathematics ; *Models, Biological ; Reproduction ; Rodentia ; *Selection, Genetic ; *Social Behavior ; }, abstract = {I present a hierarchy of models that illustrate, within the framework of inclusive fitness theory, how demographic factors can predispose a species to the evolution of eusociality. Delayed reproductive maturation lowers the inclusive fitness of a solitary foundress relative to that of a worker. Variation in age at reproductive maturity makes the worker strategy more profitable to some individuals than to others and thus predicts the coexistence of single-foundress and multiple-foundress nesting associations. Delayed reproductive maturation and variation in age at reproductive maturity also select for mixed reproductive strategies so that some individuals whose reproductive maturation is expected to be delayed can first act as workers and later switch over to the role of a queen or foundress. Assured fitness returns shows how identical mortality rates can have different consequences for workers and solitary nest foundresses because a solitary foundress will have to necessarily survive for the entire duration of development of her brood, whereas a worker can hope to get proportional fitness returns for short periods of work. In concert with assured fitness returns, delayed reproductive maturation and variation in age at reproductive maturity become more powerful in selecting for worker behavior, and mixed reproductive strategies become available to a wider range of individuals. These phenomena provide a consistently more powerful selective advantage for the worker strategy than do genetic asymmetries created by haplodiploidy.}, } @article {pmid1798336, year = {1991}, author = {Breden, F and Wade, MJ}, title = {"Runaway" social evolution: reinforcing selection for inbreeding and altruism.}, journal = {Journal of theoretical biology}, volume = {153}, number = {3}, pages = {323-337}, doi = {10.1016/s0022-5193(05)80573-9}, pmid = {1798336}, issn = {0022-5193}, support = {GM 22523/GM/NIGMS NIH HHS/United States ; }, mesh = {Alleles ; *Altruism ; Animals ; *Biological Evolution ; *Computer Simulation ; Haplotypes/genetics ; *Inbreeding ; Linkage Disequilibrium ; *Models, Genetic ; }, abstract = {Kin selection theory predicts that altruistic behaviors, those that decrease the fitness of the individual performing the behavior but increase the fitness of the recipient, can increase in frequency if the individuals interacting are closely related. Several studies have shown that inbreeding therefore generally increases the effectiveness of kin selection when fitnesses are linear, additive functions of the number of altruists in the family, although with extreme forms of altruism, inbreeding can actually retard the evolution of altruism. These models assume that a constant proportion of the population mates at random and a constant proportion practices some form of inbreeding. In order to investigate the effect of inbreeding on the evolution of altruistic behavior when the mating structure is allowed to evolve, we examined a two-locus model by computer simulation of a diploid case and illustrated the important qualitative features by mathematical analysis of a haploid case. One locus determines an individual's propensity to perform altruistic social behavior and the second locus determines the probability that an individual will mate within its sibship. We assumed positive selection for altruism and no direct selection at the inbreeding locus. We observed that the altruistic allele and the inbreeding allele become positively associated, even when the initial conditions of the model assume independence between these loci. This linkage disequilibrium becomes established, because the altruistic allele increases more rapidly in the inbreeding segment of the population. This association subsequently results in indirect selection on the inbreeding locus. However, the dynamics of this model go beyond a simple "hitch-hiking" effect, because high levels of altruism lead to increased inbreeding, and high degrees of inbreeding accelerate the rate of change of the altruistic allele in the entire population. Thus, the dynamics of this model are similar to those of "runaway" sexual selection, with gene frequency change at the two loci interactively causing rapid evolutionary change.}, } @article {pmid17742231, year = {1991}, author = {Mueller, UG}, title = {Haplodiploidy and the evolution of facultative sex ratios in a primitively eusocial bee.}, journal = {Science (New York, N.Y.)}, volume = {254}, number = {5030}, pages = {442-444}, doi = {10.1126/science.254.5030.442}, pmid = {17742231}, issn = {0036-8075}, abstract = {In eusocial Hymenoptera, the haplodiploid system of sex determination creates relatedness asymmetries such that workers are more closely related on average to their sisters than to their brothers. For such societies, kin-selection theory and sex-ratio theory predict that workers maximize their inclusive fitness by biasing the investment sex ratio toward females. To test the prediction of sex-ratio biasing, relatedness asymmetries were experimentally manipulated in colonies of the primitively eusocial bee Augochlorella striata (Halictidae: Hymenoptera) by removing or not removing foundress queens. Queenright colonies (relatedness asymmetry present) produced a more female-biased sex ratio than did queenless colonies (relatedness asymmetry absent). Worker reproduction and unmated replacement queens can be discounted as alternative explanations. Workers therefore facultatively adjusted their colony's sex ratio and, in the presence of a relatedness asymmetry, biased the investment sex ratio toward their more closely related sisters and away from their more distantly related brothers.}, } @article {pmid1935004, year = {1991}, author = {Thornhill, NW and Thornhill, R}, title = {An evolutionary analysis of psychological pain following human (Homo sapiens) rape: IV. The effect of the nature of the sexual assault.}, journal = {Journal of comparative psychology (Washington, D.C. : 1983)}, volume = {105}, number = {3}, pages = {243-252}, doi = {10.1037/0735-7036.105.3.243}, pmid = {1935004}, issn = {0735-7036}, mesh = {*Adaptation, Psychological ; Adolescent ; Adult ; Aged ; Aged, 80 and over ; *Biological Evolution ; Child ; Child Abuse, Sexual/psychology ; Child, Preschool ; Coitus/psychology ; Female ; Humans ; Infant ; Personality Development ; Rape/*psychology ; *Sexual Maturation ; Social Environment ; }, abstract = {Mental pain is hypothesized to manifest an adaptation for analyzing and coping with social problems that would have reduced inclusive fitness in human (Homo sapiens) evolutionary history. We examined this hypothesis in the psychological pain of 790 rape victims. Reproductive-aged and postreproductive-aged victims were more likely than prereproductive-aged victims to have experienced vaginal intercourse and to have had sperm present in the reproductive tract. As predicted, vaginal intercourse constituted the most psychologically devastating form of sexual assault for reproductive-aged women. Nonreproductive-aged victims were not more traumatized by vaginal rapes. When rapes included ejaculation in the victim's reproductive tract, reproductive-aged victims may have been more traumatized. These results suggest that the psychology that regulates mental pain processes information about the nature of the sexual act in the event of a woman's rape.}, } @article {pmid1935338, year = {1991}, author = {Maccoby, EE}, title = {Different reproductive strategies in males and females.}, journal = {Child development}, volume = {62}, number = {4}, pages = {676-81; discussion 682-5}, doi = {10.1111/j.1467-8624.1991.tb01560.x}, pmid = {1935338}, issn = {0009-3920}, mesh = {Animals ; Biological Evolution ; Female ; Humans ; Male ; Psychology, Social ; Puberty/psychology ; *Reproduction ; Sex Factors ; Sexual Behavior ; Sexual Behavior, Animal ; Sexual Maturation ; }, abstract = {The claim for a connection between stressful, unstable childhood environments and early pubertal maturation has only modest empirical support. However, granting the claim for purposes of discussion, and taking an evolutionary perspective, it is argued here that early puberty need not imply a shift from a "quality" toward a "quantity" reproductive strategy. Indeed, for females to make such a shift when they cannot count on secure pair bonding or paternal investment from a male would not serve their inclusive fitness interests; indeed, probably the reverse. Delayed puberty among juveniles with secure, long-continued bonds with the parental generation may serve a different evolutionary function: to minimize inbreeding. Nonevolutionary factors are more than adequate to account for precocious sexuality in individuals with stressful childhood histories.}, } @article {pmid21232428, year = {1991}, author = {Queller, DC}, title = {Group selection and kin selection.}, journal = {Trends in ecology & evolution}, volume = {6}, number = {2}, pages = {64}, doi = {10.1016/0169-5347(91)90127-J}, pmid = {21232428}, issn = {0169-5347}, } @article {pmid2045015, year = {1991}, author = {Srivastava, A}, title = {Cultural transmission of snake-mobbing in free-ranging Hanuman langurs.}, journal = {Folia primatologica; international journal of primatology}, volume = {56}, number = {2}, pages = {117-120}, doi = {10.1159/000156535}, pmid = {2045015}, issn = {0015-5713}, mesh = {*Aggression ; Animals ; Arousal ; *Behavior, Animal ; Cercopithecidae/*physiology ; Fear ; Female ; Male ; *Snakes ; }, abstract = {A focal troop of free-ranging Hanuman langurs (Presbytis entellus) living in an open scrub forest around Jodhpur was observed mobbing poisonous snakes on two different occasions during field observations of about 4,109 h. These observations of snake-mobbing demonstrate that langurs exhibit a special behaviour against 'potentially dangerous animals' which is similar to the mobbing displays of birds, and of other primates. It is suggested that the adaptive significance of snake-mobbing among langurs lies in the 'cultural transmission' of this information. These observations further support the 'kin-selection' model.}, } @article {pmid21232401, year = {1990}, author = {Heinsohn, RG and Cockburn, A and Mulder, RA}, title = {Avian cooperative breeding: Old hypotheses and new directions.}, journal = {Trends in ecology & evolution}, volume = {5}, number = {12}, pages = {403-407}, doi = {10.1016/0169-5347(90)90024-8}, pmid = {21232401}, issn = {0169-5347}, abstract = {In cooperatively breeding birds, individuals that appear capable of reproducing on their own may instead assist others with their breeding efforts. Research into avian cooperative breeding has attempted to reconcile the apparent altruism of this behaviour with maximization of inclusive fitness. Most explanations of cooperative breeding have suggested that philopatry is enforced by ecological constraints, such as a shortage of resources critical to breeding. Non-dispersers may then benefit both directly and indirectly from contributing at the nest. Recent research has shown that such benefits may be sufficient to promote philopatry, without the need for ecological constraints, and emphasizes that consideration of both costs and benefits of philopatry is essential for a comprehensive approach to the problem. The growing body of data from long-term studies of different species should combine with an improved phylogenetic perspective on cooperative breeding, to provide a useful base for future comparative analyses and experimentation.}, } @article {pmid1979447, year = {1990}, author = {Creel, S}, title = {How to measure inclusive fitness.}, journal = {Proceedings. Biological sciences}, volume = {241}, number = {1302}, pages = {229-231}, doi = {10.1098/rspb.1990.0090}, pmid = {1979447}, issn = {0962-8452}, mesh = {Animals ; Behavior, Animal ; Mathematics ; *Models, Genetic ; *Selection, Genetic ; }, abstract = {Although inclusive fitness (Hamilton 1964) is regarded as the basic currency of natural selection, difficulty in applying inclusive fitness theory to field studies persists, a quarter-century after its introduction (Grafen 1982, 1984; Brown 1987). For instance, strict application of the original (and currently accepted) definition of inclusive fitness predicts that no one should ever attempt to breed among obligately cooperative breeders. Much of this confusion may have arisen because Hamilton's (1964) original verbal definition of inclusive fitness was not in complete accord with his justifying model. By re-examining Hamilton's original model, a modified verbal definition of inclusive fitness can be justified.}, } @article {pmid21232360, year = {1990}, author = {Breden, F}, title = {Partitioning of covariance as a method for studying kin selection.}, journal = {Trends in ecology & evolution}, volume = {5}, number = {7}, pages = {224-228}, doi = {10.1016/0169-5347(90)90136-2}, pmid = {21232360}, issn = {0169-5347}, abstract = {Covariance models of selection predict gene frequency change in terms of the relationship between the fitness of an individual and its phenotype, and therefore provide a convenient method for studying evolution in natural systems. When these models are partitioned into effects acting within and between hierarchical levels of selection, they can be directly applied to questions of kin selection. In many cases, the partitioning of covariance approach to the study of kin selection is a more useful alternative to the traditional hamiltonian or inclusive fitness approach.}, } @article {pmid2320570, year = {1990}, author = {Reeve, HK and Westneat, DF and Noon, WA and Sherman, PW and Aquadro, CF}, title = {DNA "fingerprinting" reveals high levels of inbreeding in colonies of the eusocial naked mole-rat.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {87}, number = {7}, pages = {2496-2500}, pmid = {2320570}, issn = {0027-8424}, support = {R01 GM036431/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Brain Chemistry ; Crosses, Genetic ; DNA/*genetics/isolation & purification ; DNA Probes ; Female ; Heterozygote ; Homozygote ; Humans ; *Inbreeding ; Liver/analysis ; Male ; Muscles/analysis ; Nucleic Acid Hybridization ; Nucleotide Mapping ; Rodentia/*genetics ; }, abstract = {Using the technique of DNA fingerprinting, we investigated the genetic structure within and among four wild-caught colonies (n = 50 individuals) of a eusocial mammal, the naked mole-rat (Heterocephalus glaber; Rodentia: Bathyergidae). We found that DNA fingerprints of colony-mates were strikingly similar and that between colonies they were much more alike than fingerprints of non-kin in other free-living vertebrates. Extreme genetic similarity within colonies is due to close genetic relationship (mean relatedness estimate +/- SE, r = 0.81 +/- 0.10), which apparently results from consanguineous mating. The inbreeding coefficient (F = 0.45 +/- 0.18) is the highest yet recorded among wild mammals. The genetic structure of naked mole-rat colonies lends support to kin selection and ecological constraints models for the evolution of cooperative breeding and eusociality.}, } @article {pmid2112015, year = {1990}, author = {Bliss, MR}, title = {Resources, the family and voluntary euthanasia.}, journal = {The British journal of general practice : the journal of the Royal College of General Practitioners}, volume = {40}, number = {332}, pages = {117-122}, pmid = {2112015}, issn = {0960-1643}, mesh = {Aged ; Aged, 80 and over ; *Euthanasia ; Euthanasia, Active ; *Euthanasia, Active, Voluntary ; Family ; Health Expenditures/trends ; *Health Resources ; Home Care Services ; Humans ; Life Expectancy/trends ; Patient Selection ; *Resource Allocation ; Right to Die ; United Kingdom ; United States ; Withholding Treatment ; }, abstract = {Ethnological studies show that the care which societies are able to provide for their old people depends largely on available resources. However, the concept of resource depends on contemporary requirements and expectations. Modern families still try to look after their old people, but increasing longevity is making this more difficult. There is a finite ability of populations, however wealthy, to support dependent members. Resources provided to look after old people must necessarily be subtracted from those available for the other, still more important dependent group, the children, with potentially disastrous results in underfunding of social support and education. The sociobiological theory of inclusive fitness emphasizes the importance of the ways in which family members interact to help each other and try to ensure their genetic survival, even if this involves sacrificing their own interests and occasionally, their lives. Many old people do not wish for further longevity after they have become too disabled to be of service to their families, and would prefer to see limited resources being used for the young. In the USA, loss of autonomy of patients and their families owing to the practice of defensive medicine has resulted in the development of the 'living will', a legal document in which people can specify in advance what treatment they wish to accept in the event of life threatening illness. It is to be hoped that improved understanding of family relationships will make this generally unnecessary in the future and that, unless specified to the contrary, families will be allowed to decide about treatment for members who are unable to decide for themselves.(ABSTRACT TRUNCATED AT 250 WORDS)}, } @article {pmid2338839, year = {1990}, author = {Peck, JR}, title = {The evolution of outsider exclusion.}, journal = {Journal of theoretical biology}, volume = {142}, number = {4}, pages = {565-571}, doi = {10.1016/s0022-5193(05)80109-2}, pmid = {2338839}, issn = {0022-5193}, support = {MH-20752/MH/NIMH NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; *Emigration and Immigration ; Models, Biological ; Population Dynamics ; *Selection, Genetic ; }, abstract = {The rate of migration between different parts of a population can be important in determining evolutionary outcomes. This paper presents a mathematical model in which some individuals act to exclude immigrants from their group. It is shown that outsider exclusion can be favoured by evolution, even when outsider excluders incur a large cost. In addition, it is shown that the evolutionary mechanism which causes increases in the frequency of outsider excluders is a form of kin selection or group selection. A second model shows that a similar mechanisms can act to favour the evolution of reluctance to mate with immigrants.}, } @article {pmid2326762, year = {1990}, author = {Karlin, S}, title = {Levels of multiallelic overdominance fitness, heterozygote excess and heterozygote deficiency.}, journal = {Theoretical population biology}, volume = {37}, number = {1}, pages = {129-149}, doi = {10.1016/0040-5809(90)90031-p}, pmid = {2326762}, issn = {0040-5809}, support = {GM10452-26/GM/NIGMS NIH HHS/United States ; GM39907-01/GM/NIGMS NIH HHS/United States ; }, mesh = {*Alleles ; Animals ; Chromosome Mapping ; Gene Frequency/*genetics ; *Genes, Dominant ; *Genetics, Population ; *Heterozygote ; Humans ; *Models, Genetic ; *Multigene Family ; Polymorphism, Genetic/genetics ; Selection, Genetic ; }, abstract = {Concepts and results on selection balance in multiallelic systems are described. These include a multidimensional concept of heterozygote excess and heterozygote deficiency, a hierarchy of means of assessment of heterozygote advantage, comparisons and contrasts of allelic versus gametic polymorphic states, and conditions defining stable equilibria of complementary gametic sets. The concepts are illustrated in the context of viability selection and behavioral models of kin selection and for two major categories of multilocus selection regimes.}, } @article {pmid21232311, year = {1990}, author = {Kawata, M}, title = {Fluctuating populations and kin interaction in mammals.}, journal = {Trends in ecology & evolution}, volume = {5}, number = {1}, pages = {17-20}, doi = {10.1016/0169-5347(90)90007-Z}, pmid = {21232311}, issn = {0169-5347}, abstract = {Kin selection in animals favors less aggressive interaction among related individuals. If the genetic relatedness among neighbors changes with population structure and density, behavioral interaction may also change according to the population structure. Charnov and Finerty proposed a hypothesis that kin selection in voles causes population cycles if the relatedness among neighbors decreases as density increases. Field experiments have recently tested this hypothesis. Furthermore, field studies of social interaction in voles have increased in number, so that the effects of kinship on reproductive success can be reviewed. These studies indicate that although kin interaction might be an important factor affecting social behavior and reproductive success in voles, the relationships both between kinship and degree of amicable behavior or reproductive rate, and between relatedness among neighbors and population density, are far less simple than had been supposed.}, } @article {pmid2323684, year = {1990}, author = {Clarke, MR}, title = {Behavioral development and socialization of infants in a free-ranging group of howling monkeys (Alouatta palliata).}, journal = {Folia primatologica; international journal of primatology}, volume = {54}, number = {1-2}, pages = {1-15}, doi = {10.1159/000156422}, pmid = {2323684}, issn = {0015-5713}, support = {RR00164/RR/NCRR NIH HHS/United States ; }, mesh = {Age Factors ; Alouatta/*psychology ; Animals ; Behavior, Animal/*physiology ; Cebidae/*psychology ; Feeding Behavior ; Female ; Humans ; Interpersonal Relations ; Male ; Maternal Behavior ; Motor Activity ; Play and Playthings ; Sex Characteristics ; *Social Behavior ; Weaning ; }, abstract = {A 22-month field study was carried out on free-ranging mantled howlers in Costa Rica. Six female and 5 male infants were observed systematically from birth until they died, left the group, or the study ended. Interaction patterns, activity patterns, and proximity data were analyzed from 703 h of focal observations and 753 h of ad lib observations. Developmental trends in weaning and nonmother care were associated with mothers' feeding patterns, suggesting an increase in maternal feeding efficiency. As howler immigration patterns resulted in groups of adults of low relatedness, analyses based on social bonding or kin selection were inappropriate, and socialization patterns instead appeared to prepare howler infants to respond predictably in an adult world. Females, which were more sociable as adults, were also more sociable as infants, initiating interactions and reacting positively. They also exhibited less weaning stress than males. Males, which were forced out of the group sooner, remained solitary longer, and primarily interacted with adult females as adults, were forced to be independent sooner, reacted negatively to interactions, and ceased interacting with adult males by 3 months of age. Ecological constraints on development could not be determined from this study, although there was no evidence for developmental trends being influenced by predator stress.}, } @article {pmid2234607, year = {1990}, author = {Hart, BL}, title = {Behavioral adaptations to pathogens and parasites: five strategies.}, journal = {Neuroscience and biobehavioral reviews}, volume = {14}, number = {3}, pages = {273-294}, doi = {10.1016/s0149-7634(05)80038-7}, pmid = {2234607}, issn = {0149-7634}, support = {RR05457/RR/NCRR NIH HHS/United States ; }, mesh = {*Adaptation, Psychological ; Animals ; Bacterial Infections/*psychology ; *Behavior ; Humans ; Parasitic Diseases/*psychology ; Virus Diseases/*psychology ; }, abstract = {The ever present threat of viral, bacterial, protozoan and metazoan parasites in the environment of wild animals is viewed as responsible for the natural selection of a variety of behavioral patterns that enable animals to survive and reproduce in this type of environment. Several lines of research, some quite recent, point to five behavioral strategies that vertebrates utilize to increase their personal or inclusive fitness in the face of parasites (broadly defined to include pathogens). These are: 1) avoidance of parasites; 2) controlled exposure to parasites to potentiate the immune system; 3) behavior of sick animals including anorexia and depression to overcome systemic febrile infections; 4) helping sick animals; 5) sexual selection for mating partners with the genetic endowment for resistance to parasites. The point is made that to consider a behavioral pattern as having evolved to serve a parasite control function the parasite or causative agent should be shown to adversely impact the animal's fitness and the behavior in question must be shown to help animals, or their offspring or group mates, in combating their exposure, or reducing their vulnerability, to the parasite.}, } @article {pmid2108914, year = {1990}, author = {Feistner, AT and Price, EC}, title = {Food-sharing in cotton-top tamarins (Saguinus oedipus).}, journal = {Folia primatologica; international journal of primatology}, volume = {54}, number = {1-2}, pages = {34-45}, doi = {10.1159/000156424}, pmid = {2108914}, issn = {0015-5713}, mesh = {Age Factors ; Animals ; Callitrichinae/*psychology ; *Feeding Behavior ; Female ; Male ; Saguinus/*psychology ; Sex Characteristics ; }, abstract = {Food-sharing behaviour was observed in 9 captive families of cotton-top tamarins (range 4-14 individuals per group), during meals of fresh fruit. Food was transferred to infants by their parents and older sibs in response to begging, and was also offered to them without prior solicitation. Older, mature, reproductively suppressed individuals shared more than young immature monkeys. Infants in larger families received more food than those in smaller ones, though individuals in smaller families shared more. Transfer to infants increased to a maximum at 12 weeks of age and then declined gradually. At one year of age they no longer received food from others. Food sharing by older siblings is a form of helping behaviour which may increase their inclusive fitness, and benefit parents, both directly, by reducing the costs they incur in rearing young, and indirectly, by increasing the amount of food available to infants.}, } @article {pmid2634163, year = {1989}, author = {Nee, S}, title = {Does Hamilton's rule describe the evolution of reciprocal altruism?.}, journal = {Journal of theoretical biology}, volume = {141}, number = {1}, pages = {81-91}, doi = {10.1016/s0022-5193(89)80010-4}, pmid = {2634163}, issn = {0022-5193}, mesh = {*Altruism ; *Biological Evolution ; *Genetics, Behavioral ; Humans ; Models, Biological ; Phenotype ; Selection, Genetic ; }, abstract = {On intuitive grounds, many have felt that Hamilton's Rule, br greater than c, should describe the evolution of reciprocal altruism and "green beard" genes. However, difficulties have been encountered in applying the rule to situations in which the benefits an individual receives are a function of his own phenotype as well as that of his partner. These difficulties are resolved by recognising that there are two important coefficients of genetic relatedness: r1 is the coefficient already familiar to sociobiologists from the applications of Hamilton's Rule to kin selection; r2 is the coefficient of genetic relatedness between individuals who express the same phenotype. It is shown that the r in Hamilton's Rule is a weighted average of these two coefficients. The weights, along with r1 and r2, are intuitively meaningful. A remarkable fact is that r2 = 1, regardless of how genotype determines phenotype.}, } @article {pmid21227378, year = {1989}, author = {Pamilo, P}, title = {Estimating relatedness in social groups.}, journal = {Trends in ecology & evolution}, volume = {4}, number = {11}, pages = {353-355}, doi = {10.1016/0169-5347(89)90091-8}, pmid = {21227378}, issn = {0169-5347}, abstract = {Genetic relatedness is a vital parameter in the evolution of social behaviour by kin selection. It can be easily estimated using genetic markers and calculating the genotypic correlation or regression of group members. Spatial gene frequency differentiation, due to population subdivision or isolation by distance, boosts the relatedness estimates. In such cases it may be useful to partition the estimate into components, the operational relatedness is normally that among individuals in social groups within the same subpopulation. Although it is straightforward to estimate the average relatedness in social groups, estimating values for specific individuals with the help of genetic markers is still problematic. Current estimators tend to give biased values and the sampling error is large. In spite of these shortcomings, studies of social behaviour combining relatedness and reproductive success are sorely needed.}, } @article {pmid16594034, year = {1989}, author = {Queller, DC}, title = {The evolution of eusociality: Reproductive head starts of workers.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {86}, number = {9}, pages = {3224-3226}, pmid = {16594034}, issn = {0027-8424}, abstract = {In eusocial species, many individuals forego their personal reproduction to aid the reproduction of their mother or other relatives. Kin selection can favor such behavior for any positive degree of relatedness to the individuals being helped, provided the helper gives them a sufficiently large fitness gain compared to the fitness cost of giving up its own reproduction. Yet, little attention has been given to the question of how helpers can aid relatives more than they can aid themselves, particularly in species lacking morphologically specialized castes. One answer to this question is explored here. When a potential helper is born into a colony that has immature young, its help may quickly bring those young to the age of independence. If it left to reproduce alone, it would have to bring its own offspring all the way to independence. The consequences of early mortality therefore differ: solitary reproducers that die early will fail to bring any young to independence, while helpers that die at the same age may have made substantial contributions. Published data from four polistine wasps show that high adult mortality rates and long periods of offspring dependence combine to provide a large selective advantage for worker behavior.}, } @article {pmid17246495, year = {1989}, author = {Harper, AB}, title = {Evolutionary Stability for Interactions among Kin under Quantitative Inheritance.}, journal = {Genetics}, volume = {121}, number = {4}, pages = {877-889}, pmid = {17246495}, issn = {0016-6731}, abstract = {The theory of evolutionarily stable strategies (ESS) predicts the long-term evolutionary outcome of frequency-dependent selection by making a number of simplifying assumptions about the genetic basis of inheritance. I use a symmetrized multilocus model of quantitative inheritance without mutation to analyze the results of interactions between pairs of related individuals and compare the equilibria to those found by ESS analysis. It is assumed that the fitness changes due to interactions can be approximated by the exponential of a quadratic surface. The major results are the following. (1) The evolutionarily stable phenotypes found by ESS analysis are always equilibria of the model studied here. (2) When relatives interact, one of the two conditions for stability of equilibria differs between the two models; this can be accounted for by positing that the inclusive fitness function for quantitative characters is slightly different from the inclusive fitness function for characters determined by a single locus. (3) The inclusion of environmental variance will in general change the equilibrium phenotype, but the equilibria of ESS analysis are changed to the same extent by environmental variance. (4) A class of genetically polymorphic equilibria occur, which in the present model are always unstable. These results expand the range of conditions under which one can validly predict the evolution of pairwise interactions using ESS analysis.}, } @article {pmid2520021, year = {1989}, author = {Geiger, G}, title = {Sociobiology and the structural stability of behavior patterns.}, journal = {Mathematical biosciences}, volume = {93}, number = {1}, pages = {117-145}, doi = {10.1016/0025-5564(89)90016-3}, pmid = {2520021}, issn = {0025-5564}, mesh = {Animals ; *Behavior, Animal ; Game Theory ; *Genetics, Behavioral ; Insecta ; Mutation/genetics ; *Social Behavior ; }, abstract = {A structural stability approach to population-genetic systems and to dynamic evolutionary games is attempted in order to examine the theoretical significance of sociobiological selection models. A criterion of weak selection is derived that is not restricted to differential reproduction in polymorphic systems but describes possible directions of evolutionary change in time scales governed by genetic mutation rates. The criterion applies to the problems of how the initial mutational basis of an adaptive trait may be established and how this may happen, for analogous traits, independently in different species. Two basic sociobiological concepts are reconsidered with reference to the criterion. It is shown that W. D. Hamilton's condition of increases in inclusive fitness due to altruistic interactions among kin expresses the structural instability of populations against the evolution of altruistic behavior. Using the dynamic approach to evolutionary game theory, it is demonstrated that if a behavioral phenotype is an evolutionarily stable strategy, it is structurally stable against perturbations of the fitness payoffs, provided selection is weak. These results are applied to material problems of the evolution of animal social behavior.}, } @article {pmid2910063, year = {1989}, author = {Beaumont, JJ and Steenland, K and Minton, A and Meyer, S}, title = {A computer program for incidence density sampling of controls in case-control studies nested within occupational cohort studies.}, journal = {American journal of epidemiology}, volume = {129}, number = {1}, pages = {212-219}, doi = {10.1093/oxfordjournals.aje.a115111}, pmid = {2910063}, issn = {0002-9262}, support = {ES03767/ES/NIEHS NIH HHS/United States ; }, mesh = {Cohort Studies ; *Epidemiologic Methods ; Humans ; Mathematical Computing ; Occupational Diseases/*epidemiology ; Prospective Studies ; Retrospective Studies ; Risk Factors ; *Software ; }, abstract = {A nested case-control study is a case-control study performed with a cohort study. The nested case-control design is useful because the number of study subjects for whom risk factor information is needed is smaller than in the original cohort study. The approach is especially helpful when collection of data is expensive or time consuming, as when it is necessary to contact subjects or next of kin. Selection of controls in nested case-control studies is best performed with a method called "incidence density" sampling. An approach to incidence density sampling that yields a valid estimate of the rate ratio is sampling without replacement from noncases at the time of case occurrence. To implement this approach, a system of computer programs was written that randomly selects a user defined number of controls for each case. The case-control data produced by this program can be analyzed by conditional logistic regression.}, } @article {pmid2816530, year = {1989}, author = {Barel, CD and Anker, GC and Witte, F and Hoogerhoud, RJ and Goldschmidt, T}, title = {Constructional constraint and its ecomorphological implications.}, journal = {Acta morphologica Neerlando-Scandinavica}, volume = {27}, number = {1-2}, pages = {83-109}, pmid = {2816530}, issn = {0001-6225}, mesh = {*Anatomy, Comparative ; Animals ; *Models, Biological ; *Physiology ; }, abstract = {This paper analyses the role of constructional morphology in explaining the limitations on the interactions between an organism and those factors in its environment which are potentially relevant to its inclusive fitness. Constructional morphology deals with the relations between functionally relevant anatomical units (apparatuses or functional components) and thereby demonstrates what quantitative and qualitative constraints there are on combining units necessary for environmental interactions. It is argued that investigations on the relations between form and environment (ecological morphology) should (1) consider three types of relations: form-form, form-function and function-environment factor, (2) include behavioral and physiological ecology and (3) not be limited to a particular stage, but include as much of ontogeny as possible.}, } @article {pmid2616792, year = {1989}, author = {Plutchik, R and Van Praag, H}, title = {The measurement of suicidality, aggressivity and impulsivity.}, journal = {Progress in neuro-psychopharmacology & biological psychiatry}, volume = {13 Suppl}, number = {}, pages = {S23-34}, doi = {10.1016/0278-5846(89)90107-3}, pmid = {2616792}, issn = {0278-5846}, mesh = {*Aggression ; Brain/physiology ; Heart Rate ; Humans ; *Impulsive Behavior ; Models, Psychological ; Risk Factors ; *Suicide ; Surveys and Questionnaires ; }, abstract = {1. From an evolutionary point of view aggressive behavior increases the chances of individual survival as well as inclusive fitness. 2. There are brain structures and biochemical systems that are involved in the regulation of aggressive behavior. 3. Genetic studies have revealed genetic contributions to aggressive as well as impulsive behaviors. 4. Research has demonstrated correlations between measures of suicidality, violence and impulsivity. 5. A two-step model of countervailing forces has been developed that identifies amplifiers and attenuators of the aggressive impulse. This model has enabled us to determine a set of variables that influence suicide but not violence and another set that influences violence but not suicide.}, } @article {pmid17799732, year = {1988}, author = {Queller, DC and Strassmann, JE and Hughes, CR}, title = {Genetic relatedness in colonies of tropical wasps with multiple queens.}, journal = {Science (New York, N.Y.)}, volume = {242}, number = {4882}, pages = {1155-1157}, doi = {10.1126/science.242.4882.1155}, pmid = {17799732}, issn = {0036-8075}, abstract = {The evolution of worker behavior in the social insects is usually explained by kin selection: although workers do not produce offspring, they do reproduce their genes by aiding the reproduction of relatives. The most difficult case for kin selection theory would be species in which workers are fully capable of reproducing but instead opt to rear brood of low relatedness. These conditions are perhaps best fulfilled by the swarm-founding wasps because they have little caste differentiation and their colonies usually have multiple queens, which should lower relatedness. Estimates of within-colony relatedness for three species in this group confirm that it is sometimes (but not always) very low. Inbreeding is negligible in these species, so the hypothesis that inbreeding may raise relatedness is not supported. The maintenance of worker behavior in such species is a significant challenge for kin selection theory.}, } @article {pmid3256715, year = {1988}, author = {Motro, U}, title = {Evolutionarily stable strategies of mutual help between relatives having unequal fertilities.}, journal = {Journal of theoretical biology}, volume = {135}, number = {1}, pages = {31-39}, doi = {10.1016/s0022-5193(88)80172-3}, pmid = {3256715}, issn = {0022-5193}, mesh = {Altruism ; *Biological Evolution ; *Consanguinity ; *Fertility ; *Helping Behavior ; Humans ; Mathematics ; *Models, Genetic ; Selection, Genetic ; }, abstract = {The evolutionarily stable strategy of mutual help between relatives having unequal fertilities is studied in a kin selection model, which also takes into account competition between kins and the possibility of reciprocation. It turns out that competition and reciprocation can establish ESSs which are completely different from those expected by Hamilton's basic theory.}, } @article {pmid3232119, year = {1988}, author = {Taylor, PD}, title = {Inclusive fitness models with two sexes.}, journal = {Theoretical population biology}, volume = {34}, number = {2}, pages = {145-168}, doi = {10.1016/0040-5809(88)90039-1}, pmid = {3232119}, issn = {0040-5809}, mesh = {Animals ; Female ; Gender Identity ; Gene Frequency ; Male ; *Models, Genetic ; *Selection, Genetic ; *Sex Ratio ; Sexual Behavior, Animal ; }, abstract = {Much recent work has focused on the transition from G. R. Price's (1970, Nature 227, 520-521) formula for allele frequency change to an inclusive fitness condition for the selective advantage of a certain behaviour. In case there is any kind of asymmetry between the sexes, the analysis must keep track of the two sexes separately, and this leads to a number of different forms of the expression for inclusive fitness. In this paper I gather these forms together and note the assumptions needed to make each valid. I also show how inclusive fitness should be formulated when the behaviour of the actor is controlled by another individual. I illustrate the inclusive fitness approach with a sex allocation example in a haplodiploid population with a local breeding structure.}, } @article {pmid3381088, year = {1988}, author = {Peck, JR and Feldman, MW}, title = {Kin selection and the evolution of monogamy.}, journal = {Science (New York, N.Y.)}, volume = {240}, number = {4859}, pages = {1672-1674}, doi = {10.1126/science.3381088}, pmid = {3381088}, issn = {0036-8075}, support = {GM 10452/GM/NIGMS NIH HHS/United States ; GM 28016/GM/NIGMS NIH HHS/United States ; }, mesh = {*Altruism ; Animals ; *Biological Evolution ; Female ; Genotype ; Humans ; Male ; Mathematics ; Polymorphism, Genetic ; Recombination, Genetic ; *Sexual Behavior, Animal ; *Sibling Relations ; }, abstract = {A two-locus genetic model is studied in which one locus controls the tendency of individuals to act altruistically toward siblings and the other locus controls the mating habits of females. It is demonstrated that genetic variation at the altruism locus is often sufficient to induce an increase in the frequency of genes that cause females to produce all of their offspring with a single mate. This occurs because of nonrandom associations that develop between genes that cause altruism and those that affect female mating behavior. The results provide a new explanation for the evolution of monogamy, and they suggest a previously unexplored mechanism for the evolution of a variety of other behavioral traits as well.}, } @article {pmid3414792, year = {1988}, author = {Ehardt, CL}, title = {Absence of strongly kin-preferential behavior by adult female sooty mangabeys (Cercocebus atys).}, journal = {American journal of physical anthropology}, volume = {76}, number = {2}, pages = {233-243}, doi = {10.1002/ajpa.1330760212}, pmid = {3414792}, issn = {0002-9483}, support = {RR-00165/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Behavior, Animal/*physiology ; Cercopithecidae/*physiology ; Female ; }, abstract = {The objective of this study was to test the hypothesis that kin-preferential behavior would be present in sooty mangabeys (Cercocebus atys), a species taxonomically close to baboons and macaques. The affiliative behavior of the adult female members of a large captive group of these mangabeys was analyzed to test this prediction. These females groomed, were approached by, were in proximity to, and were in contact with their kin significantly more than expected, but only when all kin were included in the analysis. Removal of only the mother-infant (less than 1 year) dyadic interactions removed all significant kin effects. Kin-preferential behavior was also absent in affiliative interactions among the adult females as a class. Affiliation between mothers and offspring significantly exceeded that for all other kinship categories (such as siblings, etc.), and affiliation with kin other than offspring did not differ from that with nonkin adults. In their interactions with nonkin, the adult females showed some preference (duration of grooming) for those adult females of similar age, an effect predicted by the intensity of interaction among members of the same age cohort during development. These similar-aged females may also be paternally related. In comparing these results with the existing literature on kin-preferential behavior, two conclusions may be reached: (1) age and degree of kinship are primary factors that must be considered in order to avoid the existing overgeneralization of the importance of kinship in primate social organization, and (2) the role and importance of affiliative behavior in kin-selection theory should perhaps be re-examined in light of questions raised by this study.}, } @article {pmid19291860, year = {1988}, author = {Libertini, G}, title = {An adaptive theory of increasing mortality with increasing chronological age in populations in the wild.}, journal = {Journal of theoretical biology}, volume = {132}, number = {2}, pages = {145-162}, doi = {10.1016/s0022-5193(88)80153-x}, pmid = {19291860}, issn = {0022-5193}, mesh = {*Adaptation, Physiological ; Animals ; Animals, Wild/*physiology ; *Biological Evolution ; Longevity ; Models, Theoretical ; *Mortality ; Survival ; }, abstract = {An "increasing mortality with increasing chronological age in populations in the wild" (IMICAW) is a phenomenon shown by many species, and the greater or smaller (or non-existent) IMICAW has an adaptive value, since it reduces the "mean duration of life" (ML). As Leopold (1961) pointed out, a smaller ML brings about a greater spreading velocity, within the species, of any advantageous mutation.However, this is an argument of group selection and is, therefore, inadequate to demonstrate that within a species a C gene causing IMICAW is stable compared with a C' allele not having this effect. The problem may be solved if we consider the inclusive fitness of C with the hypothesis that the dead individuals are replaced by kin individuals. In such a case, even with low values of the coefficient of relationship (Hamilton, 1971) of the substituting individuals, C tends to be stable and favoured by the selective mechanism as compared with C'. When the preferential replacement by kin individuals does not happen and/or when the turnover of generations is swift enough, C is not favoured and hence IMICAW loses its hypothesized adaptive value. In such cases, survival curves must be of type II or III of Pianka's classification (1970). It is discussed if IMICAW might be a consequence of the action of many harmful genes that express themselves tardily in the course of life.}, } @article {pmid3049398, year = {1988}, author = {Cheal, DJ}, title = {Theories of serial flow in intergenerational transfers.}, journal = {International journal of aging & human development}, volume = {26}, number = {4}, pages = {261-273}, doi = {10.2190/V2E8-UEAT-5MJ7-UQ6F}, pmid = {3049398}, issn = {0091-4150}, mesh = {*Altruism ; Economics ; Ego ; Family ; Humans ; *Social Values ; *Socioeconomic Factors ; }, abstract = {Recent improvements in the economic position of the elderly population necessitate a more thorough understanding of the serial flow of economic supports from preceding to succeeding generations. Five theories which might extend our understanding of the decision rules employed in intergenerational transfers are discussed. They are: social exchange theory, the kin selection theory of altruism, human capital theory, social constructivist theory, and rational transfers theory. The underlying assumptions of these theories are presented and compared, and models of intergenerational transactions are developed. Comparative studies are recommended in order to gain deeper insights into the relative strengths and weaknesses of these different views of relationships between the generations.}, } @article {pmid3479804, year = {1987}, author = {Lynch, M}, title = {Evolution of intrafamilial interactions.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {84}, number = {23}, pages = {8507-8511}, pmid = {3479804}, issn = {0027-8424}, mesh = {*Altruism ; *Biological Evolution ; *Family ; Humans ; Selection, Genetic ; Social Behavior/*physiology ; }, abstract = {A theory for the evolution of behavioral interactions among relatives is developed that allows for genetic correlations between the types of behavior that are expressed in different social contexts. Both theoretical and empirical considerations indicate that such genetic constraints will almost certainly be common in natural populations. It is shown that when genetic correlations between elements of social behavior exist, Hamilton's rule inaccurately describes the conditions for evolution by way of kin selection. The direction in which social organization evolves is a delicate function of the genetic covariance structure among behaviors expressed as an offspring, sibling, parent, etc. A change in this covariance structure caused by random genetic drift or by a change in environment for a population exhibiting genotype-environment interaction can cause the population to suddenly cross a threshold into a new selective domain. Consequently, radical changes in social organization may arise between closely related species without any major shift in selective pressures external to the population.}, } @article {pmid21227877, year = {1987}, author = {Haig, D}, title = {Kin conflict in seed plants.}, journal = {Trends in ecology & evolution}, volume = {2}, number = {11}, pages = {337-340}, doi = {10.1016/0169-5347(87)90110-8}, pmid = {21227877}, issn = {0169-5347}, abstract = {Kin selection theory proposes that individuals value the reproductive success of relatives at a rate determined by their probability of shared alleles. The theory predicts when the interests of relatives are in accord and when they conflict. Though kin selection arguments have revolutionized the study of animal behavior, they have only recently been applied to plants. Kin selection has already been claimed to explain the formation of endosperm by double fertilization. This is the character that distinguishes angiosperms from gymnosperms. Plant life cycles involve interactions among kinds of relatives not encountered in animals. These interactions should be a fertile field for new applications of theory and the testing of ideas originally developed elsewhere.}, } @article {pmid21227868, year = {1987}, author = {Armitage, KB}, title = {Social dynamics of mammals: Reproductive success, kinship and individual fitness.}, journal = {Trends in ecology & evolution}, volume = {2}, number = {9}, pages = {279-284}, doi = {10.1016/0169-5347(87)90037-1}, pmid = {21227868}, issn = {0169-5347}, abstract = {Apparent altruism, in which an individual seemingly decreases its evolutionary fitness by assisting others, can confer benefits if the individual assists kin. Thus, an animal can increase its total or inclusive fitness by producing offspring (direct fitness) and/or helping kin to reproduce (indirect fitness). Although kin selection has been suggested as the mechanism underlying the formation of mammalian societies, many species act as if they attempt to maximize the direct fitness component of their inclusive fitness.}, } @article {pmid21227865, year = {1987}, author = {Page, RE and Breed, MD}, title = {Kin recognition in social bees.}, journal = {Trends in ecology & evolution}, volume = {2}, number = {9}, pages = {272-275}, doi = {10.1016/0169-5347(87)90034-6}, pmid = {21227865}, issn = {0169-5347}, abstract = {Kin recognition in social insects has become a central issue in sociobiology because studies of the recognition abilities of social insects provide a test of kin selection theory. W.D. Hamilton(1) formalized kin selection theory by showing how individuals can gain fitness by increasing the reproductive output of relatives (kin). The social interactions of individuals, or groups, should be influenced by the genetic structure of the population. The ability to recognize kin can increase the adaptive value of social behavior by modulating it according to genetic relationship. From this, the specific prediction emerges: if individuals can distinguish among others with which they interact on the basis of the degree to which they are related, then behavior should be biased preferentially toward more closely related reproductive individuals.}, } @article {pmid4042620, year = {1985}, author = {Baker, SC and Estep, DQ}, title = {Kinship and affiliative behavior patterns in a captive group of Celebes black apes (Macaca nigra).}, journal = {Journal of comparative psychology (Washington, D.C. : 1983)}, volume = {99}, number = {3}, pages = {356-360}, pmid = {4042620}, issn = {0735-7036}, support = {RR-00165/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Animals, Zoo/*genetics ; Behavior, Animal/*physiology ; Female ; Genetics, Behavioral ; Grooming ; *Interpersonal Relations ; Macaca/*genetics ; Male ; Selection, Genetic ; Spatial Behavior ; }, abstract = {The influence of matrilineal kinship on four socially affiliative behavior patterns--grooming, contact, proximity, and play--was studied in a little-known primate species, the Celebes black ape (Macaca nigra). Twenty group-living black apes, comprising four genealogical groups, were observed for more than 100 hr; data were collected by the instantaneous scan technique. Animals spent more time than was expected by chance grooming, in contact with, and in proximity to their matrilineal relatives, but they did not play with relatives more than was expected. The proximal mechanisms responsible for these results are unknown, and increased familiarity among matrilineal relatives may have influenced the interaction patterns in the group. The results obtained in this study are similar to those of many others that demonstrate differential behavior toward kin, and they are consistent with the theory that animals may increase their inclusive fitness by interacting preferentially with relatives.}, } @article {pmid3862097, year = {1985}, author = {Feldman, MW and Cavalli-Sforza, LL and Peck, JR}, title = {Gene-culture coevolution: models for the evolution of altruism with cultural transmission.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {82}, number = {17}, pages = {5814-5818}, pmid = {3862097}, issn = {0027-8424}, support = {GM10452/GM/NIGMS NIH HHS/United States ; GM20467/GM/NIGMS NIH HHS/United States ; GM28016/GM/NIGMS NIH HHS/United States ; }, mesh = {Alleles ; *Altruism ; Animals ; *Biological Evolution ; *Culture ; *Genes ; Genotype ; Haploidy ; Humans ; Models, Theoretical ; Phenotype ; Sibling Relations ; }, abstract = {Models of sexual haploids under kin selection are constructed. The trait of altruism is transmitted vertically from parent to child, but not in a strictly genetic manner. Two systems of altruism are considered: parent-to-offspring and sib-to-sib. In the former case it is shown that even when Hamilton's conditions for the success of genetically determined altruism are met, genes that increase the transmission of altruism may not invade the population. With sib-to-sib altruism, such genes will always increase initially.}, } @article {pmid3973366, year = {1985}, author = {Kivett, VR}, title = {Consanguinity and kin level: their relative importance to the helping network of older adults.}, journal = {Journal of gerontology}, volume = {40}, number = {2}, pages = {228-234}, doi = {10.1093/geronj/40.2.228}, pmid = {3973366}, issn = {0022-1422}, mesh = {Adolescent ; Adult ; Age Factors ; Aged/*psychology ; Child ; *Consanguinity ; Female ; Health Status ; *Helping Behavior ; Humans ; Male ; Marriage ; Middle Aged ; Sex Factors ; Social Class ; *Social Environment ; *Social Support ; }, abstract = {The purpose of this research was to examine the help received by older rural-transitional adults from seven levels of consanguineous and affinal kin and to determine the correlates of help received according to kin type. The sample consisted of 321 working class adults, aged 65 to 96 years, selected by a compact cluster sampling procedure. The data showed that kin beyond the child, child-in-law levels was of little functional importance in the helping network of older adults. Proximity to kin was the only common denominator of help received across all levels of kin. Results of the study appear to support, in part, the kin-selection theory in that helping behaviors were usually based upon degree of consanguinity (and associated marriage tie) and extent of dependency of older adults as measured by their health status or age.}, } @article {pmid6471865, year = {1984}, author = {Aoki, K}, title = {A quantitative genetic model of two-policy games between relatives.}, journal = {Journal of theoretical biology}, volume = {109}, number = {1}, pages = {111-126}, doi = {10.1016/s0022-5193(84)80114-9}, pmid = {6471865}, issn = {0022-5193}, mesh = {Altruism ; Animals ; Competitive Behavior ; *Game Theory ; *Models, Genetic ; Selection, Genetic ; }, abstract = {Equations are derived for the change per generation of the population mean of the probability that an individual adopts a policy 1 as opposed to a policy 2 in a behavioral interaction between two diploid individuals of the same generation in which two policies are possible. The probability is assumed to be a quantitative genetic trait determined by many additively acting genes of small effects and an independent environmental component. Equations are derived for the case that interactions occur at random between all members of the population and also for the case that interactions occur between relatives of the same average degree of relatedness. It is assumed that each group of relatives and the number of such groups is sufficiently large. For a quantitative genetic trait with the additional assumption of unlinked loci the latter equation can be heuristically derived from the first by substituting the corresponding inclusive fitness effects. When per locus selection coefficients are small and linkage equilibrium holds, the average degree of relatedness can be equated approximately with Wright's coefficient of relationship. Thus, the quantitative genetic model provides a genetic basis for the inclusive fitness approach toward games between relatives. By contrast, in a monogenic system with major gene effects we obtain substantially different results which contradict those obtained by the inclusive fitness approach in game theory. Applications are made to the hawk-dove game, and the simple and iterated forms of the prisoner's dilemma.}, } @article {pmid6748682, year = {1984}, author = {Eshel, I}, title = {On the evolution of an inner conflict.}, journal = {Journal of theoretical biology}, volume = {108}, number = {1}, pages = {65-76}, doi = {10.1016/s0022-5193(84)80169-1}, pmid = {6748682}, issn = {0022-5193}, mesh = {Alleles ; Animals ; Female ; Male ; *Models, Genetic ; *Mutation ; *Selection, Genetic ; Sex Chromosomes ; }, abstract = {A simple two-locus genetic model is suggested, in which a "conflict" between alleles located at different loci leads to the establishment under certain conditions of fixation of a double mutant type which is different from the wild type only in the fact that a smaller fraction of its offspring, either males or females, survive to maturity. The double mutant is characterized by conflicting features determined by the different loci. The results are obtained by an analysis of an exact genetic model, though they are partly interpreted in terms of locus-dependent kin selection.}, } @article {pmid6487228, year = {1984}, author = {Rushton, JP and Russell, RJ and Wells, PA}, title = {Genetic similarity theory: beyond kin selection.}, journal = {Behavior genetics}, volume = {14}, number = {3}, pages = {179-193}, pmid = {6487228}, issn = {0001-8244}, mesh = {Altruism ; Animals ; Ethnicity ; Family ; Genetics, Behavioral ; Humans ; Marriage ; Models, Genetic ; *Selection, Genetic ; }, } @article {pmid16593437, year = {1984}, author = {Matessi, C and Karlin, S}, title = {On the evolution of altruism by kin selection.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {81}, number = {6}, pages = {1754-1758}, pmid = {16593437}, issn = {0027-8424}, abstract = {A general model for the evolution of altruism is formulated. Central to the model is a pair of local fitness functions, which prescribe the fitness of the altruist and selfish phenotypes as functions of the composition of local groups into which prereproductives are subdivided. When the local groups are sibships or other kin groups, the model is one for kin selection. Functions for cost and benefit of altruism are derived from the fitness functions. Conditions for evolution of altruism are then determined in terms of cost and benefit. It is shown that the Hamilton rule has quantitative validity only in the special case of linear fitness functions. Sufficient conditions are found for qualitative validity of the Hamilton rule. Qualitative violation of the rule is also possible.}, } @article {pmid6515694, year = {1984}, author = {de Catanzaro, D}, title = {Suicidal ideation and the residual capacity to promote inclusive fitness: a survey.}, journal = {Suicide & life-threatening behavior}, volume = {14}, number = {2}, pages = {75-87}, doi = {10.1111/j.1943-278x.1984.tb00339.x}, pmid = {6515694}, issn = {0363-0234}, mesh = {*Adaptation, Psychological ; Adult ; Family ; Female ; Humans ; Male ; Middle Aged ; Motivation ; Psychological Tests ; Social Adjustment ; Social Support ; Suicide/*psychology ; Suicide, Attempted/psychology ; }, abstract = {It has been argued that suicide relates to a diminished residual capacity to promote inclusive fitness, defined as the welfare and reproduction of self and kin. The present study examined whether this relationship is reflected in suicidal and subsuicidal ideation in the general population. A questionnaire concerning parameters of inclusive fitness, suicidal ideation and experience, and attitudes toward the value of life was distributed to samples of the general public and university undergraduates. Analyses indicated significant moderate relationships between inclusive fitness and suicidal ideation in both samples. Among items most strongly related to reported suicidal ideation were expectations of poor future health, perceptions of being burdensome, and unstable heterosexual relationships, with importance of other factors depending on age.}, } @article {pmid6400148, year = {1984}, author = {Epstein, E and Guttman, R}, title = {Mate selection in man: evidence, theory, and outcome.}, journal = {Social biology}, volume = {31}, number = {3-4}, pages = {243-278}, doi = {10.1080/19485565.1984.9988579}, pmid = {6400148}, issn = {0037-766X}, mesh = {Female ; Genetics, Medical ; Humans ; Male ; *Marriage ; Models, Psychological ; Social Behavior ; }, } @article {pmid6575395, year = {1983}, author = {Aoki, K}, title = {A quantitative genetic model of reciprocal altruism: a condition for kin or group selection to prevail.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {80}, number = {13}, pages = {4065-4068}, pmid = {6575395}, issn = {0027-8424}, mesh = {*Altruism ; Animals ; *Genetics, Population ; Group Processes ; Humans ; Mathematics ; *Models, Genetic ; Models, Psychological ; *Selection, Genetic ; }, abstract = {A condition is derived for reciprocal altruism to evolve by kin or group selection. It is assumed that many additively acting genes of small effect and the environment determine the probability that an individual is a reciprocal altruist, as opposed to being unconditionally selfish. The particular form of reciprocal altruism considered is TIT FOR TAT, a strategy that involves being altruistic on the first encounter with another individual and doing whatever the other did on the previous encounter in subsequent encounters with the same individual. Encounters are restricted to individuals of the same generation belonging to the same kin or breeding group, but first encounters occur at random within that group. The number of individuals with which an individual interacts is assumed to be the same within any kin or breeding group. There are 1 + i expected encounters between two interacting individuals. On any encounter, it is assumed that an individual who behaves altruistically suffers a cost in personal fitness proportional to c while improving his partner's fitness by the same proportion of b. Then, the condition for kin or group selection to prevail is [Formula: see text] if group size is sufficiently large and the group mean and the within-group genotypic variance of the trait value (i.e., the probability of being a TIT-FOR-TAT strategist) are uncorrelated. Here, C, Vb, and Tb are the population mean, between-group variance, and between-group third central moment of the trait value and r is the correlation between the additive genotypic values of interacting kin or of individuals within the same breeding group. The right-hand side of the above inequality is monotone decreasing in C if we hold Tb/Vb constant, and kin and group selection become superfluous beyond a certain threshold value of C. The effect of finite group size is also considered in a kin-selection model.}, } @article {pmid6572955, year = {1983}, author = {Darlington, PJ}, title = {Evolution: questions for the modern theory.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {80}, number = {7}, pages = {1960-1963}, pmid = {6572955}, issn = {0027-8424}, mesh = {Animals ; *Biological Evolution ; Models, Biological ; Selection, Genetic ; }, abstract = {The blind spot of the present generation of evolutionists is failure to see the consequences and limits of natural selection. Darwinian natural selection is a costly process of differential elimination of individuals. The widely accepted misdefinition of natural selection as differential reproduction mistakenly hides the Darwinian process and its cost. And current theories of selfish genes, inclusive fitness, and kin selection are incompatible with Darwinian selection. Implicitly, if not explicitly, they postulate genes that favor themselves but reduce the Darwinian fitness of the individuals carrying them. Such genes would not survive; they would eliminate themselves by causing the selective elimination of their carriers. Critical questions that evolutionists should be asked are suggested. My own "unhappy conclusion" is that, because most biologists have forgotten what natural selection is, much current evolutionary and sociobiological theory presented by the most influential evolutionists is mistaken and dangerous. Anthropologists and sociologists are wise to distrust it.}, } @article {pmid6839262, year = {1983}, author = {Sloman, L}, title = {Inclusive fitness, altruism and family adaptation.}, journal = {Canadian journal of psychiatry. Revue canadienne de psychiatrie}, volume = {28}, number = {1}, pages = {18-23}, doi = {10.1177/070674378302800105}, pmid = {6839262}, issn = {0706-7437}, mesh = {*Adaptation, Psychological ; Adult ; *Altruism ; Child ; Child Rearing ; *Family ; Family Therapy ; Gender Identity ; Hierarchy, Social ; Humans ; Parent-Child Relations ; Personality Development ; Self Concept ; *Social Adjustment ; }, abstract = {An integrative model of family functioning is put forward using a sociobiological framework. Three key sociobiological concepts that have a relevance to family interaction are inclusive fitness, altruism, and a struggle for status. The term 'inclusive fitness' encompasses the parents' own fitness and that of their kith and kin. Altruism refers to how parents promote the survival of their progeny and extended family. The struggle for status refers to a struggle for power and prestige. According to the author's hypothesis 'inclusive fitness' exerts its influence through the struggle for status which in turn influences the degree of altruism and the level of 'family adaptation'. The parents' level of inclusive fitness largely determines the level of family adaptation which in turn influences the growth and individuation of the next generation. A common negative outcome of failure in the struggle for status and power is a displacement of the struggle for power into a family context. Failure in a struggle for status between peer group members would in a pretechnological society probably have reflected a relative lack of fitness. Failure in the struggle for status is likely to generate maladaptive cycles in the family which will lower the inclusive fitness of the parents. A concept of ideal family functioning is derived from sociobiology and specifically related to a high inclusive fitness in the parents. The author argues that sociobiological concepts can contribute to the development of an integrative theory of family behaviour. The clinical implications of this model are explored.}, } @article {pmid6572904, year = {1983}, author = {Engels, WR}, title = {Evolution of altruistic behavior by kin selection: an alternative approach.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {80}, number = {2}, pages = {515-518}, pmid = {6572904}, issn = {0027-8424}, support = {GM27867/GM/NIGMS NIH HHS/United States ; GM30948/GM/NIGMS NIH HHS/United States ; }, mesh = {*Altruism ; *Biological Evolution ; Family ; Humans ; Mathematics ; Models, Genetic ; Models, Psychological ; *Selection, Genetic ; }, abstract = {The evolution of altruistic and selfish behavior by kin selection has been analyzed previously by asking which types of behavior are favored by natural selection. A type of behavior is defined as a given cost/benefit ratio, c/b, in terms of Darwinian fitness. An alternative approach is to consider c/b itself as a quantitative character subject to natural selection and evolving toward an equilibrium. This approach allows consideration of a continuum of behavioral options as opposed to just two alternatives as in the previous work. Environmental restrictions on the availability of opportunities for fitness transactions are imposed so that the total benefit an individual can provide for or take from his relatives increases with his c/b ratio. General conditions for stable equilibria are derived. These depend only on the coefficient of relationship between donor and recipient (r) and the function describing the availability of benefit. They are independent of the heritability and variance in the population. Under weak selection, the equilibrium c/b ratio will be r/2 for altruistic behavior and 1/(2r) for selfish behavior. By contrast, standard theory predicts that all altruistic acts with c/b ratios less than r will be favored, and no equilibrium can be predicted except under certain special conditions where only two behavioral options are available. In general, these results show that evolution of the donor's behavior (altruism) tends to maximize the quantity rb--c, and evolution of the recipient (selfish behavior) maximizes b--rc.}, } @article {pmid6366644, year = {1983}, author = {Wills, GD and Wesley, AL and Moore, FR and Sisemore, DA}, title = {Social interactions among rodent conspecifics: a review of experimental paradigms.}, journal = {Neuroscience and biobehavioral reviews}, volume = {7}, number = {3}, pages = {315-323}, doi = {10.1016/0149-7634(83)90035-0}, pmid = {6366644}, issn = {0149-7634}, mesh = {Animals ; Conditioning, Operant ; Consummatory Behavior ; Cooperative Behavior ; Discrimination, Psychological ; Drive ; Emotions ; Ethology/methods ; Mice ; Motor Activity ; Psychological Theory ; Rats ; Sibling Relations ; Smell ; *Social Behavior ; Social Facilitation ; Species Specificity ; }, abstract = {The authors suggest that kin selection theory offers a different perspective from which to examine social interactions among rodent conspecifics. Paradigms designed to investigate various interactions among rodent conspecifics are presented, and include simple affiliative behaviors, social facilitation, and cooperation. It is established that many species of rodents are appropriately social to use as subjects under investigation in research which focuses on topics such as kin selection. Studies reporting positive results as well as some reporting negative or inconclusive results have been presented for the purpose of informing the reader under which conditions we might expect specific social behaviors to occur. It is concluded that a combined method of a sociobiological perspective using established experimental procedures will offer unique opportunities for the investigation of specific predictions suggested by kin selection theory.}, } @article {pmid6755531, year = {1982}, author = {Masters, RD}, title = {Is sociobiology reactionary? The political implications of inclusive-fitness theory.}, journal = {The Quarterly review of biology}, volume = {57}, number = {3}, pages = {275-292}, doi = {10.1086/412803}, pmid = {6755531}, issn = {0033-5770}, mesh = {Altruism ; *Biological Evolution ; Humans ; Models, Genetic ; Models, Psychological ; *Social Behavior ; }, abstract = {Is inclusive fitness theory, popularly called "sociobiology," necessarily conservative or reactionary? While this criticism is usually focused on the extension of evolutionary reasoning to human behavior, it implies that contemporary biological theory is ideologically biased. Historical, logical, and empirical evidence shows, however, that models of natural selection based on reproductive success--particularly when redefined in terms of inclusive fitness--are not incompatible with scientific objectivity. This approach is a cost-benefit analysis of social behavior, akin to "rational actor" models in economics, game theory, and public-choice theory. Derived from the "social-contract" tradition in Western political philosophy, epitomized by such varied thinkers as Thrasymachus, Hobbes, and Rousseau, such a calculus of individual advantage has had as broad a range of ideological overtones as the contrasting "'sociological" tradition of Aristotle, Marx, and Durkheim. Previous evolutionary explanations of human society have likewise suggested diverse political conclusions. Indeed, if inclusive-fitness models do have political implications, they could well challenge existing sociopolitical beliefs and institutions rather than support them.}, } @article {pmid7154687, year = {1982}, author = {Toro, M and Abugov, R and Charlesworth, B and Michod, RE}, title = {Exact versus heuristic models of kin selection.}, journal = {Journal of theoretical biology}, volume = {97}, number = {4}, pages = {699-713}, doi = {10.1016/0022-5193(82)90368-x}, pmid = {7154687}, issn = {0022-5193}, mesh = {Alleles ; Altruism ; Gene Frequency ; Humans ; *Models, Genetic ; *Selection, Genetic ; Sibling Relations ; }, } @article {pmid7124939, year = {1982}, author = {Smith, DG}, title = {Inbreeding in three captive groups of rhesus monkeys.}, journal = {American journal of physical anthropology}, volume = {58}, number = {4}, pages = {447-451}, doi = {10.1002/ajpa.1330580413}, pmid = {7124939}, issn = {0002-9483}, support = {N01-HD-0-2828/HD/NICHD NIH HHS/United States ; RR00169/RR/NCRR NIH HHS/United States ; }, mesh = {Animals ; Crosses, Genetic ; Female ; *Inbreeding ; Macaca/*genetics ; Macaca mulatta/*genetics ; Male ; Probability ; }, abstract = {Using electrophoretic and serological genetic markers each of 17 potentially inbred matings in three groups of rhesus monkeys could be classified as either inbred or noninbred matings. Although nine of these 17 matings involved either father-daughter or paternal half-sib matings, only 7.4 were expected by chance alone. At least two, and possibly as many as three, of the nine cases of inbreeding involved father-daughter matings. Thus, no evidence of avoidance of inbreeding was observed in the closed captive groups of rhesus monkeys studied. Colony management policies must be developed to minimize the opportunity for or the deleterious effects of both father-daughter and half-sib matings. Furthermore, kin selection theory should consider why kin recognition, if it occurs, does not lead to avoidance of inbreeding.}, } @article {pmid7088188, year = {1982}, author = {Grafen, A}, title = {How not to measure inclusive fitness.}, journal = {Nature}, volume = {298}, number = {5873}, pages = {425-426}, doi = {10.1038/298425a0}, pmid = {7088188}, issn = {0028-0836}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Genetics, Population ; Mathematics ; Models, Genetic ; }, } @article {pmid16593160, year = {1982}, author = {Eshel, I and Cavalli-Sforza, LL}, title = {Assortment of encounters and evolution of cooperativeness.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {79}, number = {4}, pages = {1331-1335}, pmid = {16593160}, issn = {0027-8424}, abstract = {The method of evolutionary stable strategies (ESS), in its current form, is confronted with a difficulty when it tries to explain how some social behaviors initiate their evolution. We show that this difficulty may be removed by changing the assumption made tacitly in game theory (and in ESS) of randomness of meetings or encounters. In reality, such randomness seems to be rare in nature. Family, population and social structure, customs, and habits impose various types of deviation from randomness. Introducing nonrandomness of meeting in a way formally similar to assortative mating, we show that the bar to initial increase of inherited cooperative or altruistic behaviors can be removed, provided there is sufficient assortment of meetings. Family structure may cause contacts predominantly between certain types of relatives, and one can reconstruct some results of classical kin selection in terms of evolutionary stable strategy with assortative meetings. Neighbor effects and group selection might be similarly treated. Assortment need not be a passive consequence of population and social structure, but it can also be actively pursued. Behaviors favoring the choice of cooperative companions will have the effect of favoring the evolution of cooperativeness. It can be shown that discrimination in the choice of companions, especially if combined with assortment, can favor the development of cooperativeness, making initial increase of cooperative behavior possible even at levels of assortment passively imposed which would not be adequate, per se, to guarantee the increase of cooperativeness. It is possible that, in some cases, cooperativeness and behavior favoring some type of assortment are coselected.}, } @article {pmid6951823, year = {1982}, author = {Pamilo, P}, title = {Genetic population structure in polygynous formica ants.}, journal = {Heredity}, volume = {48}, number = {Pt 1}, pages = {95-106}, doi = {10.1038/hdy.1982.10}, pmid = {6951823}, issn = {0018-067X}, mesh = {Animals ; Ants/*genetics ; Enzymes/genetics ; Female ; *Gene Frequency ; Genetic Markers ; Genotype ; Male ; }, abstract = {Genetic population structures, both mating and interaction structures, were investigated in three polygynous Formica ants by examining how genotype frequencies are distributed among the nests in their populations. The study is based on electrophoretically analysed enzyme polymorphisms. The patterns of genotypic variation among single-nest workers suggest that polygyny is functional in all the three species. The observed genotype frequencies indicate outbreeding within the study areas, and no spatial microdifferentiation in gene frequencies is detected. The coexistent gynes in nests of both F. transkaucasica and F. polyctena are genetically related to each other, and the same holds for worker nest mates. These results support the hypothesis that polygyny is favoured by kin selection. The lack of genetic relatedness among gyne nest mates in the highly polygynous F. aquilonia suggests that additional factors, such as mutualism or parental parasitism, are probably involved in the evolution of polygyny.}, } @article {pmid16593074, year = {1981}, author = {Uyenoyama, MK and Feldman, MW and Mueller, LD}, title = {Population genetic theory of kin selection: Multiple alleles at one locus.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {78}, number = {8}, pages = {5036-5040}, pmid = {16593074}, issn = {0027-8424}, abstract = {Exact population genetic models of one-locus sib-to-sib kin selection with an arbitrary number of alleles are studied. First, a natural additive scaling is established for the genotypic value associated with probabilities of performance of altruism. Two classes of polymorphic equilibria are possible, one corresponding to the usual one-locus viability equilibria and the other reflecting the kin-selection assumptions of the model. At both, the covariance between additive genotypic value and genotypic fitness vanish. Further, the sign of this covariance determines the fate of rare alleles introduced near the first class of equilibria. In addition, the covariance explains the differences between Hamilton's rule, which results from Hardy-Weinberg assumptions, and exact initial increase conditions.}, } @article {pmid16593061, year = {1981}, author = {Darlington, PJ}, title = {Genes, individuals, and kin selection.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {78}, number = {7}, pages = {4440-4443}, pmid = {16593061}, issn = {0027-8424}, abstract = {The altruistic-gene theory of kin selection requires conditions so improbable that its reality is doubtful. The gene-quantity theory, including the theory of inclusive fitness, assumes that selection acts on sums of kins' genes, but no effective mechanism is apparent. Insect and human societies may have evolved by individual selection, in two steps: first something made staying together advantageous to individuals, and then altruistic behaviors evolved in net-gain lotteries, also (statistically) advantageous to individuals. Kin selection is not required in these or any other unequivocal cases; the theory should be reexamined and probably abandoned. The probability of kin selection is further reduced by the cost of evolution by selection. Much current evolutionary mathematics and determinist sociobiology, which ignore how the cost of selection limits the precision of adaptations, including adaptive behaviors, may be dangerously unrealistic.}, } @article {pmid7256682, year = {1981}, author = {Eshel, I and Motro, U}, title = {Kin selection and strong evolutionary stability of mutual help.}, journal = {Theoretical population biology}, volume = {19}, number = {3}, pages = {420-433}, doi = {10.1016/0040-5809(81)90029-0}, pmid = {7256682}, issn = {0040-5809}, support = {1 RO1 HD 12731-01/HD/NICHD NIH HHS/United States ; 10452//PHS HHS/United States ; 20816//PHS HHS/United States ; }, mesh = {*Biological Evolution ; Consanguinity ; Game Theory ; *Genetics, Population ; *Models, Genetic ; Selection, Genetic ; }, } @article {pmid7207614, year = {1981}, author = {Blaustein, AR and O'Hara, RK}, title = {Genetic control for sibling recognition?.}, journal = {Nature}, volume = {290}, number = {5803}, pages = {246-248}, doi = {10.1038/290246a0}, pmid = {7207614}, issn = {0028-0836}, mesh = {Animals ; Genetics, Behavioral ; Larva ; Ranidae/*genetics ; *Sibling Relations ; }, abstract = {The ability to distinguish between kin and non-kin is critical to current theories of altruistic behaviour and kin selection. Hamilton predicted that individuals would behave differently towards one another depending on the genetic relatedness between them. When either proximity to or familiarity with kin is a good predictor of relatedness, the mechanism by which favouritism towards kin is accomplished may not require special kin recognition abilities. However, if proximity and familiarity are poor predictors of kinship, favouritism (hence increases in inclusive fitness) could only be achieved by the differential recognition of kin and non-kin. We have previously shown that Cascades frog (Rana cascadae) tadpoles reared with siblings prefer to associate with siblings over non-siblings. The present study is the first to report that totally naive individuals (R. cascadae tadpoles) prefer to associate with siblings over non-siblings. Because tadpoles were separated before hatching and reared apart from other individuals, results suggest that the ability of these tadpoles to discriminate between siblings and non-siblings has some innate component.}, } @article {pmid7266013, year = {1981}, author = {Abugov, R and Michod, RE}, title = {On the relation of family structured models and inclusive fitness models for kin selection.}, journal = {Journal of theoretical biology}, volume = {88}, number = {4}, pages = {743-754}, doi = {10.1016/0022-5193(81)90248-4}, pmid = {7266013}, issn = {0022-5193}, mesh = {Altruism ; Family ; Gene Frequency ; Genotype ; *Models, Genetic ; *Selection, Genetic ; *Social Behavior ; }, } @article {pmid7265997, year = {1981}, author = {Charlesworth, B and Charnov, EL}, title = {Kin selection in age-structured populations.}, journal = {Journal of theoretical biology}, volume = {88}, number = {1}, pages = {103-119}, doi = {10.1016/0022-5193(81)90330-1}, pmid = {7265997}, issn = {0022-5193}, mesh = {*Aging ; Alleles ; Animals ; Female ; Fertility ; Gene Frequency ; Genetics, Population ; Male ; *Models, Genetic ; Mutation ; Reproduction ; *Selection, Genetic ; }, } @article {pmid7341670, year = {1981}, author = {Ruse, M}, title = {Are there gay genes? Sociobiology and homosexuality.}, journal = {Journal of homosexuality}, volume = {6}, number = {4}, pages = {5-34}, doi = {10.1300/j082v06n04_02}, pmid = {7341670}, issn = {0091-8369}, mesh = {Female ; *Heterozygote ; *Homosexuality ; Humans ; Male ; Parent-Child Relations ; *Selection, Genetic ; }, abstract = {This paper considers recent hypotheses prepared by sociobiologists purportedly giving Darwinian evolutionary explanations of human homosexuality. Four models are considered: balanced superior heterozygote fitness, kin selection, parental manipulation, and homosexuality as a maladaptive side effect of intensive natural selection for superior male heterosexual behavior. The evidence for the models is reviewed, and their philosophical adequacy is considered in some depth. It is argued that although the models pass obvious methodological hurdles and meet other criteria, as yet, the evidence for their applicability is indecisive.}, } @article {pmid16592940, year = {1980}, author = {Boyd, R and Richerson, PJ}, title = {Effect of phenotypic variation on kin selection.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {77}, number = {12}, pages = {7506-7509}, pmid = {16592940}, issn = {0027-8424}, abstract = {An expression for the equilibrium of the mean phenotypic value of a quantitative character is derived for a model in which the fitness of an individual depends on its own phenotype and the mean phenotypic value of a group of related individuals. When selection is weak the equilibrium mean is well predicted by Hamilton's k > 1/r rule (k is the ratio of mean fitness gained by recipient of altruistic behavior to mean fitness lost by donor; r is mean coefficient of relationship between donor and recipient). When selection is strong, however, the equilibrium mean depends on the heritability of the character. Low heritability can lead to substantially more "altruism" than predicted by the k > 1/r rule.}, } @article {pmid7230845, year = {1980}, author = {Rothstein, SI}, title = {Reciprocal altruism and kin selection are not clearly separable phenomena.}, journal = {Journal of theoretical biology}, volume = {87}, number = {2}, pages = {255-261}, doi = {10.1016/0022-5193(80)90359-8}, pmid = {7230845}, issn = {0022-5193}, mesh = {*Altruism ; Animals ; Biological Evolution ; Genes ; Humans ; *Selection, Genetic ; }, } @article {pmid17815158, year = {1980}, author = {Michod, RE and Abugov, R}, title = {Adaptive topography in family-structured models of kin selection.}, journal = {Science (New York, N.Y.)}, volume = {210}, number = {4470}, pages = {667-669}, doi = {10.1126/science.210.4470.667}, pmid = {17815158}, issn = {0036-8075}, abstract = {Adaptive topographies provide a means of summarizing the qualitative dynamics of evolution. Inclusive fitness serves as an organizing concept in much of sociobiology. Through the use of Sewall Wright's "fitness function," the theoretical equivalence of these concepts for weak selection in family-structured populations is demonstrated.}, } @article {pmid17815157, year = {1980}, author = {Wade, MJ}, title = {Kin selection: its components.}, journal = {Science (New York, N.Y.)}, volume = {210}, number = {4470}, pages = {665-667}, doi = {10.1126/science.210.4470.665}, pmid = {17815157}, issn = {0036-8075}, abstract = {Change in gene frequency under kin selection is the sum of two components, namely, [See equation in the PDF file], a change in gene frequency caused by individual selection, and [See equation in the PDF file], a change caused by group selection. For the evolution of altruistic traits by kin selection, [See equation in the PDF file] is always negative-that is, individual selection operates against altruism-and [See equation in the PDF file] is always positive, so that selection between groups favors altruism. Hamilton's rule specifies the conditions under which [See equation in the PDF file]-that is, the conditions necessary for intergroup selection to override individual selection.}, } @article {pmid7470021, year = {1980}, author = {Palmour, RM and Cronin, JE and Childs, A and Grunbaum, BW}, title = {Studies of primate protein variation and evolution: microelectrophoretic detection.}, journal = {Biochemical genetics}, volume = {18}, number = {7-8}, pages = {793-808}, pmid = {7470021}, issn = {0006-2928}, mesh = {Animals ; Biological Evolution ; Cercopithecus/*genetics ; Chlorocebus aethiops/*genetics ; Electrophoresis, Cellulose Acetate ; Enzymes/genetics ; Hominidae/*genetics ; Humans ; Macaca/*genetics ; Pan troglodytes/*genetics ; *Polymorphism, Genetic ; }, abstract = {Genetic variation at 16 protein and enzyme loci in Ceropithecus aethiops and several other primate species has been surveyed, using cellulose acetate microelectrophoresis. Resolution of several standard variant proteins is comparable to that achieved on starch gel or polyacrylamide gel. Although both intraspecific and interspecific variation was observed for some loci, the data generally support the concept that extracellular proteins are more likely to be polymorphic within a species, while intracellular proteins generally vary between species, if at all. These methodologies are particularly appropriate for screening multiple-locus variation in large numbers of samples; their relevance to studies of molecular evolution and evaluation of theories of kin selection is discussed.}, } @article {pmid7374772, year = {1980}, author = {Wu, HM and Holmes, WG and Medina, SR and Sackett, GP}, title = {Kin preference in infant Macaca nemestrina.}, journal = {Nature}, volume = {285}, number = {5762}, pages = {225-227}, doi = {10.1038/285225a0}, pmid = {7374772}, issn = {0028-0836}, mesh = {Age Factors ; Animals ; Behavior, Animal/*physiology ; Family ; Female ; Macaca/*physiology ; Male ; Orientation ; Social Behavior ; }, abstract = {The ability to recoginize conspecifics is a prerequisite for many types of social behaviour, including, for example, parent-offspring relation, mate selection and recognition, territorial defence and dominance coalitions. This ability is of special importance to Hamilton's kin selection hypothesis, which predicts that an individual's behaviour towards a conspecific will depend on the degree of genetic relatedness between them. Although recognition depends on previous experience between individuals in some species, this does not precluded the possibility that recognition could occur in its absence. For example, juveniles who disperse before nonlittermate siblings are born or adult males who do not participate in rearing their young might benefit from recognition abilities that are independent of prior association between the individuals. Here we show that young pigtail macaques prefer to interact with a related over an unrelated monkey in a laboratory test. Because subjects were separated from their dams at birth and reared apart from all other relatives, results suggest that kin recognition can occur in the absence of prior association with relatives.}, } @article {pmid16592808, year = {1980}, author = {Wilson, EO and Hölldobler, B}, title = {Sex differences in cooperative silk-spinning by weaver ant larvae.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {77}, number = {4}, pages = {2343-2347}, pmid = {16592808}, issn = {0027-8424}, abstract = {Final-instar larvae of weaver ants (Oecophylla longinoda) use their silk for nest construction rather than for cocoon spinning; this commitment represents a shift from entirely selfish to entirely cooperative behavior that occurred after the emergence of the phylogenetically advanced subfamily Formicinae. Male larvae were found to have smaller silk glands and to contribute substantially less silk to nest construction. The hypothesis of kin selection appears to be the most plausible and parsimonious explanation of this sex difference, but other, individual-level modes of selection have not been eliminated.}, } @article {pmid537387, year = {1979}, author = {Orlove, MJ}, title = {A reconciliation of inclusive fitness and personal fitness approaches: a proposed correcting term for the inclusive fitness formula.}, journal = {Journal of theoretical biology}, volume = {81}, number = {3}, pages = {577-586}, doi = {10.1016/0022-5193(79)90055-9}, pmid = {537387}, issn = {0022-5193}, mesh = {Altruism ; Animals ; Computers ; Gene Frequency ; Genotype ; Humans ; *Models, Genetic ; *Selection, Genetic ; Wasps/genetics ; }, } @article {pmid537369, year = {1979}, author = {Michod, R}, title = {Genetical aspects of kin selection: effects of inbreeding.}, journal = {Journal of theoretical biology}, volume = {81}, number = {2}, pages = {223-233}, doi = {10.1016/0022-5193(79)90162-0}, pmid = {537369}, issn = {0022-5193}, mesh = {Animals ; *Inbreeding ; Mathematics ; Models, Genetic ; }, } @article {pmid42060, year = {1979}, author = {Clutton-Brock, TH and Harvey, PH}, title = {Comparison and adaptation.}, journal = {Proceedings of the Royal Society of London. Series B, Biological sciences}, volume = {205}, number = {1161}, pages = {547-565}, doi = {10.1098/rspb.1979.0084}, pmid = {42060}, issn = {0950-1193}, mesh = {*Adaptation, Biological ; Adaptation, Psychological ; Animals ; Deer ; Ecology ; Genetic Variation ; Lepidoptera ; Papio ; Phylogeny ; Species Specificity ; }, abstract = {It has sometimes been suggested that the term adaptation should be reserved for differences with a known genetic basis. We argue that adaptation should be defined by its effects rather than by its causes as any difference between two phenotypic traits (or trait complexes) which increases the inclusive fitness of its carrier. This definition implies that some adaptations may arise by means other than natural selection. It is particularly important to bear this in mind when behavioural traits are considered. Critics of the 'adaptationist programme' have suggested that an important objection to many adaptive explanations is that they rely on ad-hoc arguments concerning the function of previously observed differences. We suggest that this is a less important problem (because evolutionary explanations generally claim some sort of generality and are therefore testable) than the difficulties arising from confounding variables. These are more widespread and more subtle than is generally appreciated. Not all differences between organisms are directly adapted to ecological variation. The form of particular traits usually constrains the form of value that other traits can take, presenting several obstacles to attempts to relate variation in morphological or behavioural characteristics directly to environmental differences. We describe some of the repercussions of differences in body size among vertebrates and ways in which these can be allowed for. In addition, a variety of evolutionary processes can produce non-adaptive differences between organisms. One way of distinguishing between these and adaptations is to investigate adaptive trends in phylogenetically different groups of species.}, } @article {pmid513793, year = {1979}, author = {Orlove, MJ}, title = {Putting the diluting effect into inclusive fitness.}, journal = {Journal of theoretical biology}, volume = {78}, number = {3}, pages = {449-450}, doi = {10.1016/0022-5193(79)90344-8}, pmid = {513793}, issn = {0022-5193}, mesh = {Animals ; Female ; Gene Frequency ; Gene Pool ; Male ; *Models, Genetic ; *Selection, Genetic ; Wasps ; }, } @article {pmid470412, year = {1979}, author = {Johnson, LL}, title = {Kin selection in finite sibships.}, journal = {Journal of theoretical biology}, volume = {77}, number = {3}, pages = {379-381}, doi = {10.1016/0022-5193(79)90363-1}, pmid = {470412}, issn = {0022-5193}, mesh = {Alleles ; *Altruism ; Diploidy ; *Family ; Gene Frequency ; *Models, Biological ; }, } @article {pmid762537, year = {1979}, author = {Essock-Vitale, SM and Fairbanks, LA}, title = {Sociobiological theories of kin selection and reciprocal altruism and their relevance for psychiatry.}, journal = {The Journal of nervous and mental disease}, volume = {167}, number = {1}, pages = {23-28}, doi = {10.1097/00005053-197901000-00003}, pmid = {762537}, issn = {0022-3018}, mesh = {Adult ; *Altruism ; Animals ; Child ; Family Characteristics ; Hospitals, Psychiatric ; Humans ; Mental Disorders/genetics/*psychology ; *Psychological Theory ; *Selection, Genetic ; *Social Behavior ; United States ; }, abstract = {The revelance of sociobiology to psychiatry is examined through a consideration of the theories of kin selection and reciprocal altruism. Predictions developed from these theories are compared with currently available mental-health statistics. The theory of kin selection is used to predict a positive correlation between mental health and the existence of an active kin-support system. Similarly, the theory of reciprocal altruism is used to predict a positive correlation between mental health and the existence of an active friend-support system. The findings tend to support both sets of predictions in that individuals with access to kin-support and/or friend-support systems are less likely to be hospitalized with psychiatric disorders than are individuals without access to such systems. Sociobiology may be useful to psychiatry in that in some cases it provides: a) a new focus on the adaptive functions of human behavior which may serve to aid the psychiatrist in evaluating individual problems; b) functional predictions which may help to identify segments of the population which are more at risk for psychiatric disorders than others, thereby providing guidelines for preventive psychiatry; and c) direction for research into unexplored aspects of human social relationships and their relevance to psychiatric disorders.}, } @article {pmid488866, year = {1979}, author = {Silk, JB}, title = {Feeding, foraging, and food sharing behavior of immature chimpanzees.}, journal = {Folia primatologica; international journal of primatology}, volume = {31}, number = {1-2}, pages = {123-142}, doi = {10.1159/000155876}, pmid = {488866}, issn = {0015-5713}, mesh = {Animals ; *Feeding Behavior ; Female ; Male ; Maternal Behavior ; *Pan troglodytes ; }, abstract = {Observations of chimpanzees under naturalistic conditions show that nutritional autonomy increases as young individuals mature. Substantial proportions of feeding time are spent eating food obtained through solicitation. Food sharing at SOPF occurs among mother and infant pairs most frequently; less frequently between adult males and infants or juveniles, and least frequently between adult females and immature individuals. Mothers tend to share what their offspring cannot obtain independently while others primarily share what is easiest to replace. These patterns of solicitation and distribution of food are consistent with predictions based upon benefits to individuals through kin selection and/or energetic efficiency.}, } @article {pmid16592598, year = {1978}, author = {Wade, MJ}, title = {Kin selection: A classical approach and a general solution.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {75}, number = {12}, pages = {6154-6158}, pmid = {16592598}, issn = {0027-8424}, abstract = {The necessary conditions for the spread of genes that determine social behaviors and the rate of spread of these genes are derived for a simple model (single locus, two alleles, random mating, discrete generations) by using the classical population genetics approach pioneered by Haldane and the linear fitness function used previously by D. S. Wilson. These results are derived for social behaviors that are manifested by individuals within families, within pairs of families, or within groups of k families, for both diploid and haplodiploid organisms. I show that, when the groups of socially interacting individuals consist of the members of more than one family, severe restrictions are placed on the evolution of altruistic and social behaviors. Specifically, in these instances, the necessary conditions for the evolution of social behaviors are more stringent and the rate of evolution is greatly reduced.}, } @article {pmid715175, year = {1978}, author = {Schulman, SR}, title = {Kin selection, reciprocal altruism, and the principle of maximization: a reply to Sahlins.}, journal = {The Quarterly review of biology}, volume = {53}, number = {3}, pages = {283-286}, doi = {10.1086/410623}, pmid = {715175}, issn = {0033-5770}, mesh = {Biological Evolution ; *Biology ; *Family ; *Genetics, Population ; Humans ; Models, Theoretical ; Selection, Genetic ; *Social Behavior ; }, } @article {pmid703340, year = {1978}, author = {Orlove, MJ and Wood, CL}, title = {Coefficients of relationship and coefficients of relatedness in kin selection: a covariance form for the RHO formula.}, journal = {Journal of theoretical biology}, volume = {73}, number = {4}, pages = {679-686}, doi = {10.1016/0022-5193(78)90129-7}, pmid = {703340}, issn = {0022-5193}, mesh = {Animals ; Female ; Gene Frequency ; Genes ; Humans ; Male ; *Models, Biological ; Polymorphism, Genetic ; *Selection, Genetic ; }, } @article {pmid734617, year = {1978}, author = {Mirmirani, M and Oster, G}, title = {Competition, kin selection, and evolutionary stable strategies.}, journal = {Theoretical population biology}, volume = {13}, number = {3}, pages = {304-339}, doi = {10.1016/0040-5809(78)90049-7}, pmid = {734617}, issn = {0040-5809}, mesh = {Animals ; *Behavior, Animal ; *Biological Evolution ; Genetics, Behavioral ; Mathematics ; *Models, Biological ; }, } @article {pmid17757302, year = {1978}, author = {West-Eberhard, MJ}, title = {Temporary queens in metapolybia wasps: nonreproductive helpers without altruism?.}, journal = {Science (New York, N.Y.)}, volume = {200}, number = {4340}, pages = {441-443}, doi = {10.1126/science.200.4340.441}, pmid = {17757302}, issn = {0036-8075}, abstract = {In Metapolybia aztecoides some mated females produce only workers, losing in competition with other similar egg-layers before producing either males or queens. Worker production by these ultimately nonreproductive females may incidentally benefit others without lowering individual fitness (without "altruism"). It could be a by-product of mutualism rather than of kin selection or parental manipulation.}, } @article {pmid272659, year = {1978}, author = {Yokoyama, S and Felsenstein, J}, title = {A model of kin selection for an altruistic trait considered as a quantitative character.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {75}, number = {1}, pages = {420-422}, pmid = {272659}, issn = {0027-8424}, mesh = {*Altruism ; Animals ; Biological Evolution ; Environment ; Humans ; Models, Biological ; Phenotype ; *Selection, Genetic ; }, abstract = {Conditions for natural selection to favor increase of a quantitative character are derived for a model in which individuals associate in groups of size n. It is assumed that the logarithm of the fitness of an individual is the sum of two parts, one proportional to the individual's own phenotype, and the other to the mean phenotype in its group. The resulting conditions for the trait to increase under natural selection are analogous to the results found previously in single-locus kin selection models.}, } @article {pmid17770506, year = {1977}, author = {McCracken, GF and Bradbury, JW}, title = {Paternity and Genetic Heterogeneity in the Polygynous Bat, Phyllostomus hastatus.}, journal = {Science (New York, N.Y.)}, volume = {198}, number = {4314}, pages = {303-306}, doi = {10.1126/science.198.4314.303}, pmid = {17770506}, issn = {0036-8075}, abstract = {Wild colonies of greater spearnose bats were marked, censused regularly, and genotyped at three polymorphic allozyme loci. While adult composition of social units is very stable and strong polygyny results in marked changes in gene frequencies between generations, dispersal of offspring is sufficient to prevent significant genetic heterogeneities between social units. Kin selection cannot explain social cohesiveness in these highly social mammals.}, } @article {pmid886881, year = {1977}, author = {Charnov, EL}, title = {An elementary treatment of the genetical theory of kin-selection.}, journal = {Journal of theoretical biology}, volume = {66}, number = {3}, pages = {541-550}, doi = {10.1016/0022-5193(77)90301-0}, pmid = {886881}, issn = {0022-5193}, mesh = {*Biological Evolution ; Family ; Gene Frequency ; *Genetics, Population ; *Models, Biological ; Probability Theory ; Selection, Genetic ; Social Behavior ; }, } @article {pmid558481, year = {1977}, author = {Orlove, MJ}, title = {Kin selection and cancer.}, journal = {Journal of theoretical biology}, volume = {65}, number = {3}, pages = {605-607}, doi = {10.1016/0022-5193(77)90220-x}, pmid = {558481}, issn = {0022-5193}, mesh = {Animals ; *Models, Biological ; *Neoplasms ; Selection, Genetic ; *Tumor Virus Infections/genetics ; }, } @article {pmid560939, year = {1977}, author = {Kurland, JA}, title = {Kin selection in the Japanese monkey.}, journal = {Contributions to primatology}, volume = {12}, number = {}, pages = {1-145}, pmid = {560939}, issn = {0301-4231}, mesh = {Aggression ; Animals ; Biological Evolution ; Choice Behavior ; Cooperative Behavior ; Female ; Genetics, Behavioral ; *Genetics, Population ; Grooming ; Humans ; Inbreeding ; Japan ; *Macaca ; Male ; Maternal Behavior ; Pregnancy ; Sexual Behavior, Animal ; *Social Behavior ; }, } @article {pmid1007655, year = {1976}, author = {Wickler, W}, title = {Evolution-oriented ethology, kin selection, and altruistic parasites.}, journal = {Zeitschrift fur Tierpsychologie}, volume = {42}, number = {2}, pages = {206-214}, doi = {10.1111/j.1439-0310.1976.tb00966.x}, pmid = {1007655}, issn = {0044-3573}, mesh = {Animals ; Ants/parasitology ; *Behavior, Animal ; *Biological Evolution ; Dicrocoelium ; *Invertebrates ; Social Behavior ; Species Specificity ; }, abstract = {The genetic theory of social behaviour challenges ethology to incorporate the study of invertebrates and lower animals; to search for behaviour mechanisms that contribute to the maximization of "inclusive fitness" (rather than to the maintenance of the individual and the species); and to intensify the study of social consequences and interindividual differences in species-specific behaviour.}, } @article {pmid17753641, year = {1976}, author = {Hrdy, SB and Hrdy, DB}, title = {Hierarchical Relations Among Female Hanuman Langurs (Primates: Colobinae, Presbytis entellus).}, journal = {Science (New York, N.Y.)}, volume = {193}, number = {4256}, pages = {913-915}, doi = {10.1126/science.193.4256.913}, pmid = {17753641}, issn = {0036-8075}, abstract = {Female hierarchies are stable over short periods but fluctuate from year to year. In general, young females rise in rank over older and often larger female relatives, even though old females remain active in troop defense. This previously undescribed dominance system can be plausibly explained with reference to inclusive fitness theory and the concept of reproductive value.}, } @article {pmid1063734, year = {1976}, author = {Eaves, L}, title = {A model for sibling effects in man.}, journal = {Heredity}, volume = {36}, number = {2}, pages = {205-214}, doi = {10.1038/hdy.1976.25}, pmid = {1063734}, issn = {0018-067X}, mesh = {Female ; Genetic Variation ; Humans ; *Models, Biological ; *Phenotype ; Pregnancy ; *Sibling Relations ; Twins ; }, abstract = {A model is developed to specify the environmental effect of one sibling on another for a polygenic trait. Such effects are detectable in priniciple and the approach is illustrated with twin data relating to psychoticism. The relationship between the model and those employed in the treatment of kin selection is indicated.}, } @article {pmid1207178, year = {1975}, author = {Orlove, MJ}, title = {Some further insight into kin selection.}, journal = {Journal of theoretical biology}, volume = {55}, number = {2}, pages = {547-551}, doi = {10.1016/s0022-5193(75)80101-9}, pmid = {1207178}, issn = {0022-5193}, mesh = {*Genes ; Genetics, Behavioral ; *Helping Behavior ; *Models, Biological ; *Social Behavior ; }, } @article {pmid1060136, year = {1975}, author = {Levitt, PR}, title = {General kin selection models for genetic evolution of sib altruism in diploid and haplodiploid species.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {72}, number = {11}, pages = {4531-4535}, pmid = {1060136}, issn = {0027-8424}, mesh = {Biological Evolution ; Diploidy ; Genes ; Genetics, Behavioral ; Haploidy ; *Helping Behavior ; Hymenoptera/physiology ; *Models, Biological ; *Selection, Genetic ; *Social Behavior ; }, abstract = {A population genetic approach is presented for general analysis and comparison of kin selection models of sib and half-sib altruism. Nine models are described, each assuming a particular mode of inheritance, number of female inseminations, and Mendelian dominance of the altruist gene. In each model, the selective effects of altruism are described in terms of two general fitness functions, A(beta) and S(beta), giving respectively the expected fitness of an altruist and a nonaltruist as a function of the fraction of altruists beta in a given sibship. For each model, exact conditions are reported for stability at altruist and nonaltruist fixation. Under the Table 3 axions, the stability conditions may then be partially ordered on the basis of implications holding between pairs of conditions. The partial orderings are compared with predictions of the kin selection theory of Hamilton.}, } @article {pmid16592228, year = {1975}, author = {Gadgil, M}, title = {Evolution of social behavior through interpopulation selection.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {72}, number = {3}, pages = {1199-1201}, pmid = {16592228}, issn = {0027-8424}, abstract = {Under certain special conditions natural selection can be effective at the level of local populations, or demes. Such interpopulation selection will favor genotypes that reduce the probability of extinction of their parent population even at the cost of a lowered inclusive fitness. Such genotypes may be characterized by altruistic traits only in a viscous population, i.e., in a population in which neighbors tend to be closely related. In a non-viscous population the interpopulation selection will instead favor spiteful traits when the populations are susceptible to extinction through the overutilization of the habitat, and cooperative traits when it is the newly established populations that are in the greatest danger of extinction.}, } @article {pmid1121180, year = {1975}, author = {Orlove, MJ}, title = {A model of kin selection not invoking coefficients of relationship.}, journal = {Journal of theoretical biology}, volume = {49}, number = {2}, pages = {289-310}, doi = {10.1016/0022-5193(75)90173-3}, pmid = {1121180}, issn = {0022-5193}, mesh = {Biological Evolution ; Genes, Dominant ; Genetics, Population ; Mathematics ; *Models, Biological ; Models, Theoretical ; *Selection, Genetic ; }, } @article {pmid17813835, year = {1972}, author = {Eberhard, WG}, title = {Altruistic behavior in a sphecid wasp: support for kin-selection theory.}, journal = {Science (New York, N.Y.)}, volume = {175}, number = {4028}, pages = {1390-1391}, doi = {10.1126/science.175.4028.1390}, pmid = {17813835}, issn = {0036-8075}, abstract = {Trigonopsis cameronii females often work in groups of up to four individuals on single nests, and because of inbreeding and a tendency to return to the mother nest, nestmates are likely to be highly related. The altruistic behavior associated with group living, most notably the failure to steal prey from nestmates, can thus be explained by kin-selection theory.}, } @article {pmid4501113, year = {1972}, author = {Darlington, PJ}, title = {Nonmathematical models for evolution of altruism, and for group selection (peck order-territoriality-ant colony-dual-determinant model-tri-determinant model).}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {69}, number = {2}, pages = {293-297}, pmid = {4501113}, issn = {0027-8424}, mesh = {Animals ; Ants ; Behavior, Animal ; Genetics, Population ; Models, Biological ; *Philosophy ; *Selection, Genetic ; Social Dominance ; Territoriality ; }, abstract = {Mathematical biologists have failed to produce a satisfactory general model for evolution of altruism, i.e., of behaviors by which "altruists" benefit other individuals but not themselves; kin selection does not seem to be a sufficient explanation of nonreciprocal altruism. Nonmathematical (but mathematically acceptable) models are now proposed for evolution of negative altruism in dual-determinant and of positive altruism in tri-determinant systems. Peck orders, territorial systems, and an ant society are analyzed as examples. In all models, evolution is primarily by individual selection, probably supplemented by group selection. Group selection is differential extinction of populations. It can act only on populations preformed by selection at the individual level, but can either cancel individual selective trends (effecting evolutionary homeostasis) or supplement them; its supplementary effect is probably increasingly important in the evolution of increasingly organized populations.}, }