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Bibliography on: Invasive Species

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ESP: PubMed Auto Bibliography 18 Mar 2019 at 01:36 Created: 

Invasive Species

Standard Definition: Invasive species are plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause harm. Although that definition allows a logical possibility that some species might be non-native and harmless, most of time it seems that invasive species and really bad critter (or weed) that should be eradicated are seen as equivalent phrases. But, there is a big conceptual problem with that notion: every species in every ecosystem started out in that ecosystem as an invader. If there were no invasive species, all of Hawaii would be nothing but bare volcanic rock. Without an invasion of species onto land, there would be no terrestrial ecosystems at all. For the entire history of life on Earth, the biosphere has responded to perturbation and to opportunity with evolutionary innovation and with physical movement. While one may raise economic or aesthetic arguments against invasive species, it is impossible to make such an argument on scientific grounds. Species movement — the occurrence of invasive species — is the way the biosphere responds to perturbation. One might even argue that species movement is the primary, short-term "healing" mechanism employed by the biosphere to respond to perturbation — to "damage." As with any healing process, the short-term effect may be aesthetically unappealing (who thinks scabs are appealing?), but the long-term effects can be glorious.

Created with PubMed® Query: "invasive species" OR "invasion biology" OR "alien species" OR "introduced species" NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2019-03-15

Bartlett J, Convey P, SAL Hayward (2019)

Not so free range? Oviposition microhabitat and egg clustering affects Eretmoptera murphyi (Diptera: Chironomidae) reproductive success.

Polar biology, 42(2):271-284.

Understanding the physiology of non-native species in Antarctica is key to elucidating their ability to colonise an area, and how they may respond to changes in climate. Eretmoptera murphyi is a chironomid midge introduced to Signy Island (Maritime Antarctic) from South Georgia (Sub-Antarctic) where it is endemic. Here, we explore the tolerance of this species' egg masses to heat and desiccation stress encountered within two different oviposition microhabitats (ground surface vegetation and underlying soil layer). Our data show that, whilst oviposition takes place in both substrates, egg sacs laid individually in soil are at the greatest risk of failing to hatch, whilst those aggregated in the surface vegetation have the lowest risk. The two microhabitats are characterised by significantly different environmental conditions, with greater temperature fluctuations in the surface vegetation, but lower humidity (%RH) and available water content in the soil. Egg sacs were not desiccation resistant and lost water rapidly, with prolonged exposure to 75% RH affecting survival for eggs in singly oviposited egg sacs. In contrast, aggregated egg sacs (n = 10) experienced much lower desiccation rates and survival of eggs remained above 50% in all treatments. Eggs had high heat tolerance in the context of the current microhabitat conditions on Signy. We suggest that the atypical (for this family) use of egg sac aggregation in E. murphyi has developed as a response to environmental stress. Current temperature patterns and extremes on Signy Island are unlikely to affect egg survival, but changes in the frequency and duration of extreme events could be a greater challenge.

RevDate: 2019-03-15

Lenancker P, Hoffmann BD, Tay WT, et al (2019)

Strategies of the invasive tropical fire ant (Solenopsis geminata) to minimize inbreeding costs.

Scientific reports, 9(1):4566 pii:10.1038/s41598-019-41031-5.

How invasive species overcome challenges associated with low genetic diversity is unclear. Invasive ant populations with low genetic diversity sometimes produce sterile diploid males, which do not contribute to colony labour or reproductive output. We investigated how inbreeding affects colony founding and potential strategies to overcome its effects in the invasive tropical fire ant, Solenopsis geminata. Our genetic analyses of field samples revealed that 13-100% of males per colony (n = 8 males per 10 colonies) were diploid, and that all newly mated queens (n = 40) were single-mated. Our laboratory experiment in which we assigned newly mated queens to nests consisting of 1, 2, 3, or 5 queens (n = 95 ± 9 replicates) revealed that pleometrosis (queens founding their nest together) and diploid male larvae execution can compensate for diploid male load. The proportion of diploid male producing (DMP) colonies was 22.4%, and DMP colonies produced fewer pupae and adult workers than non-DMP colonies. Pleometrosis significantly increased colony size. Queens executed their diploid male larvae in 43.5% of the DMP colonies, and we hypothesize that cannibalism benefits incipient colonies because queens can redirect nutrients to worker brood. Pleometrosis and cannibalism of diploid male larvae represent strategies through which invasive ants can successfully establish despite high inbreeding.

RevDate: 2019-03-15

Kerkow A, Wieland R, Koban MB, et al (2019)

What makes the Asian bush mosquito Aedes japonicus japonicus feel comfortable in Germany? A fuzzy modelling approach.

Parasites & vectors, 12(1):106 pii:10.1186/s13071-019-3368-0.

BACKGROUND: The Asian bush mosquito Aedes japonicus japonicus is an invasive species native to East Asia and has become established in North America and Europe. On both continents, the species has spread over wide areas. Since it is a potential vector of human and livestock pathogens, distribution and dissemination maps are urgently needed to implement targeted surveillance and control in case of disease outbreaks. Previous distribution models for Europe and Germany in particular focused on climate data. Until now, effects of other environmental variables such as land use and wind remained unconsidered.

RESULTS: In order to better explain the distribution pattern of Ae. j. japonicus in Germany at a regional level, we have developed a nested approach that allows for the combination of data derived from (i) a climate model based on a machine-learning approach; (ii) a landscape model developed by means of ecological expert knowledge; and (iii) wind speed data. The approach is based on the fuzzy modelling technique that enables to precisely define the interactions between the three factors and additionally considers uncertainties with regard to the acceptance of certain environmental conditions. The model combines different spatial resolutions of data for Germany and achieves a much higher degree of accuracy than previous published distribution models. Our results reveal that a well-suited landscape structure can even facilitate the occurrence of Ae. j. japonicus in a climatically unsuitable region. Vice versa, unsuitable land use types such as agricultural landscapes and coniferous forests reduce the occurrence probability in climatically suitable regions.

CONCLUSIONS: The approach has significantly improved existing distribution models of Ae. j. japonicus for the area of Germany. We generated distribution maps with a resolution of 100 × 100 m that can serve as a basis for the design of control measures. All model input data and scripts are open source and freely available, so that the model can easily be applied to other countries or, more generally, to other species.

RevDate: 2019-03-15

Koban MB, Kampen H, Scheuch DE, et al (2019)

The Asian bush mosquito Aedes japonicus japonicus (Diptera: Culicidae) in Europe, 17 years after its first detection, with a focus on monitoring methods.

Parasites & vectors, 12(1):109 pii:10.1186/s13071-019-3349-3.

After the first detection of the Asian bush mosquito Aedes japonicus japonicus in the year 2000 in France, its invasive nature was revealed in 2008 in Switzerland and Germany. In the following years, accumulating reports have shown that Ae. j. japonicus succeeded in establishing in several European countries. Surveillance efforts suggest that there are currently four populations in Europe, with the largest one, formed by the recent fusion of several smaller populations, ranging from West Germany, with extensions to Luxembourg and French Alsace, southwards to Switzerland and continuing westwards through Liechtenstein to western Austria. This paper summarises the present distribution of Ae. j. japonicus in Europe, based on published literature and hitherto unpublished findings by the authors, and critically reviews the monitoring strategies applied. A proposal for a more standardised monitoring approach is provided, aiming at the harmonisation of future data collections for improving the comparability between studies and the suitability of collected data for further research purposes, e.g. predictive modelling approaches.

RevDate: 2019-03-14

Mandáková T, Zozomová-Lihová J, Kudoh H, et al (2019)

The story of promiscuous crucifers: origin and genome evolution of an invasive species, Cardamine occulta (Brassicaceae), and its relatives.

Annals of botany pii:5380421 [Epub ahead of print].

BACKGROUND AND AIMS: Cardamine occulta (Brassicaceae) is an octoploid weedy species (2n = 8x = 64) originated in Eastern Asia. It has been introduced to other continents including Europe and considered to be an invasive species. Despite its wide distribution, the polyploid origin of C. occulta remained unexplored. The feasibility of comparative chromosome painting (CCP) in crucifers allowed us to elucidate the origin and genome evolution in Cardamine species. We aimed to investigate the genome structure of C. occulta in comparison with its tetraploid (2n = 4x = 32, C. kokaiensis and C. scutata) and octoploid (2n = 8x = 64, C. dentipetala) relatives.

METHODS: Genomic in situ hybridization (GISH) and large-scale CCP were applied to uncover the parental genomes and chromosome composition of the investigated Cardamine species.

KEY RESULTS: All investigated species descended from a common ancestral Cardamine genome (n = 8), structurally resembling the Ancestral Crucifer Karyotype (n = 8), but differentiated by a translocation between chromosomes AK6 and AK8. Allotetraploid C. scutata originated by hybridization between two diploid species, C. parviflora and C. amara (2n = 2x = 16). By contrast, C. kokaiensis has an autotetraploid origin from a parental genome related to C. parviflora. Interestingly, octoploid C. occulta probably originated through hybridization between the tetraploids C. scutata and C. kokaiensis. The octoploid genome of C. dentipetala probably originated from C. scutata via autopolyploidization. Except for five species-specific centromere repositionings and one pericentric inversion post-dating the polyploidization events, the parental subgenomes remained stable in the tetra- and octoploids.

CONCLUSIONS: Comparative genome structure, origin and evolutionary history was reconstructed in C. occulta and related species. For the first time, whole-genome cytogenomic maps were established for octoploid plants. Post-polyploid evolution in Asian Cardamine polyploids has not been associated with descending dysploidy and intergenomic rearrangements. The combination of different parental (sub)genomes adapted to distinct habitats provides an evolutionary advantage to newly formed polyploids by occupying new ecological niches.

RevDate: 2019-03-14

Lee Y, Schmidt H, Collier TC, et al (2019)

Genome-wide divergence among invasive populations of Aedes aegypti in California.

BMC genomics, 20(1):204 pii:10.1186/s12864-019-5586-4.

BACKGROUND: In the summer of 2013, Aedes aegypti Linnaeus was first detected in three cities in central California (Clovis, Madera and Menlo Park). It has now been detected in multiple locations in central and southern CA as far south as San Diego and Imperial Counties. A number of published reports suggest that CA populations have been established from multiple independent introductions.

RESULTS: Here we report the first population genomics analyses of Ae. aegypti based on individual, field collected whole genome sequences. We analyzed 46 Ae. aegypti genomes to establish genetic relationships among populations from sites in California, Florida and South Africa. Based on 4.65 million high quality biallelic SNPs, we identified 3 major genetic clusters within California; one that includes all sample sites in the southern part of the state (South of Tehachapi mountain range) plus the town of Exeter in central California and two additional clusters in central California.

CONCLUSIONS: A lack of concordance between mitochondrial and nuclear genealogies suggests that the three founding populations were polymorphic for two main mitochondrial haplotypes prior to being introduced to California. One of these has been lost in the Clovis populations, possibly by a founder effect. Genome-wide comparisons indicate extensive differentiation between genetic clusters. Our observations support recent introductions of Ae. aegypti into California from multiple, genetically diverged source populations. Our data reveal signs of hybridization among diverged populations within CA. Genetic markers identified in this study will be of great value in pursuing classical population genetic studies which require larger sample sizes.

RevDate: 2019-03-14

Marchini GL, Maraist CA, MB Cruzan (2019)

Trait divergence, not plasticity, determines the success of a newly invasive plant.

Annals of botany, 123(4):667-679.

BACKGROUND AND AIMS: Phenotypic plasticity and genetic differentiation both play important roles in the establishment and spread of species after extra-range dispersal; however, the adaptive potential of plasticity and genetic divergence in successful invasions remains unclear.

METHODS: We measured six anatomical traits associated with drought tolerance in contrasting water environments for individuals from the invasive and native range of the bunchgrass Brachypodium sylvaticum. To represent sources contributing to admixed genotypes in the invasive range accurately, we used unique alleles to determine probabilities of genetic contribution, and utilized these as weights in our analyses. The adaptive values of plasticity and genetic differentiation were assessed using regression.

KEY RESULTS: No plasticity was found in response to water availability for any of the measured traits. Bulliform cell area and three traits related to xylem morphology displayed genetic differentiation between invasive and native ranges, indicating a shift in the invasive range towards drought-tolerant phenotypes. Genetic divergence was not consistently in the direction indicated by selection, suggesting that responses are limited by trade-offs with other traits or physical constraints.

CONCLUSIONS: Our results indicate that invasive adaptation is the consequence of post-introduction selection leading to genetic differentiation. Selection, rather than plasticity, is driving B. sylvaticum success in its invaded range.

RevDate: 2019-03-13

Urquía D, Gutierrez B, Pozo G, et al (2019)

Psidium guajava in the Galapagos Islands: Population genetics and history of an invasive species.

PloS one, 14(3):e0203737 pii:PONE-D-18-24672.

The threat of invasive plant species in island populations prompts the need to better understand their population genetics and dynamics. In the Galapagos islands, this is exemplified by the introduced guava (Psidium guajava), considered one of the greatest threats to the local biodiversity due to its effective spread in the archipelago and its ability to outcompete endemic species. To better understand its history and genetics, we analyzed individuals from three inhabited islands in the Galapagos archipelago with 11 SSR markers. Our results reveal similar genetic diversity between islands, and the populations appear to be distinct: the islands of San Cristobal and Isabela are genetically different while the population of Santa Cruz is a mixture from both. Additional evidence for genetic bottlenecks and the inference of introduction events suggests an original introduction of the species in San Cristobal, from where it was later introduced to Isabela, and finally into Santa Cruz. Alternatively, a second introduction in Isabela might have occurred. These results are contrasted with the historical record, providing a first overview of the history of P. guajava in the Galapagos islands and its current population dynamics.

RevDate: 2019-03-13

Dale AL, Feau N, Everhart SE, et al (2019)

Mitotic Recombination and Rapid Genome Evolution in the Invasive Forest Pathogen Phytophthora ramorum.

mBio, 10(2): pii:mBio.02452-18.

Invasive alien species often have reduced genetic diversity and must adapt to new environments. Given the success of many invasions, this is sometimes called the genetic paradox of invasion. Phytophthora ramorum is invasive, limited to asexual reproduction within four lineages, and presumed clonal. It is responsible for sudden oak death in the United States, sudden larch death in Europe, and ramorum blight in North America and Europe. We sequenced the genomes of 107 isolates to determine how this pathogen can overcome the invasion paradox. Mitotic recombination (MR) associated with transposons and low gene density has generated runs of homozygosity (ROH) affecting 2,698 genes, resulting in novel genotypic diversity within the lineages. One ROH enriched in effectors was fixed in the NA1 lineage. An independent ROH affected the same scaffold in the EU1 lineage, suggesting an MR hot spot and a selection target. Differences in host infection between EU1 isolates with and without the ROH suggest that they may differ in aggressiveness. Non-core regions (not shared by all lineages) had signatures of accelerated evolution and were enriched in putative pathogenicity genes and transposons. There was a striking pattern of gene loss, including all effectors, in the non-core EU2 genome. Positive selection was observed in 8.0% of RxLR and 18.8% of Crinkler effector genes compared with 0.9% of the core eukaryotic gene set. We conclude that the P. ramorum lineages are diverging via a rapidly evolving non-core genome and that the invasive asexual lineages are not clonal, but display genotypic diversity caused by MR.IMPORTANCE Alien species are often successful invaders in new environments, despite the introduction of a few isolates with a reduced genetic pool. This is called the genetic paradox of invasion. We found two mechanisms by which the invasive forest pathogen causing sudden oak and sudden larch death can evolve. Extensive mitotic recombination producing runs of homozygosity generates genotypic diversity even in the absence of sexual reproduction, and rapid turnover of genes in the non-core, or nonessential portion of genome not shared by all isolates, allows pathogenicity genes to evolve rapidly or be eliminated while retaining essential genes. Mitotic recombination events occur in genomic hot spots, resulting in similar ROH patterns in different isolates or groups; one ROH, independently generated in two different groups, was enriched in pathogenicity genes and may be a target for selection. This provides important insights into the evolution of invasive alien pathogens and their potential for adaptation and future persistence.

RevDate: 2019-03-13
CmpDate: 2019-03-13

Feis ME, John U, Lokmer A, et al (2018)

Dual transcriptomics reveals co-evolutionary mechanisms of intestinal parasite infections in blue mussels Mytilus edulis.

Molecular ecology, 27(6):1505-1519.

On theoretical grounds, antagonistic co-evolution between hosts and their parasites should be a widespread phenomenon but only received little empirical support so far. Consequently, the underlying molecular mechanisms and evolutionary steps remain elusive, especially in nonmodel systems. Here, we utilized the natural history of invasive parasites to document the molecular underpinnings of co-evolutionary trajectories. We applied a dual-species transcriptomics approach to experimental cross-infections of blue mussel Mytilus edulis hosts and their invasive parasitic copepods Mytilicola intestinalis from two invasion fronts in the Wadden Sea. We identified differentially regulated genes from an experimental infection contrast for hosts (infected vs. control) and a sympatry contrast (sympatric vs. allopatric combinations) for both hosts and parasites. The damage incurred by Mytilicola infection and the following immune response of the host were mainly reflected in cell division processes, wound healing, apoptosis and the production of reactive oxygen species (ROS). Furthermore, the functional coupling of host and parasite sympatry contrasts revealed the concerted regulation of chitin digestion by a Chitotriosidase 1 homolog in hosts with several cuticle proteins in the parasite. Together with the coupled regulation of ROS producers and antagonists, these genes represent candidates that mediate the different evolutionary trajectories within the parasite's invasion. The host-parasite combination-specific coupling of these effector mechanisms suggests that underlying recognition mechanisms create specificity and local adaptation. In this way, our study demonstrates the use of invasive species' natural history to elucidate molecular mechanisms of host-parasite co-evolution in the wild.

RevDate: 2019-03-12

Zhang Y, Pennings SC, Li B, et al (2019)

Biotic homogenization of wetland nematode communities by exotic Spartina alterniflora in China.

Ecology [Epub ahead of print].

Introduced species may homogenize biotic communities. Whether this homogenization can erase latitudinal patterns of species diversity and composition has not been well studied. We examined this by comparing nematode and microbial communities in stands of native Phragmites australis and exotic Spartina alterniflora in coastal wetlands across 18° of latitude in China. We found clear latitudinal clines in nematode diversity and functional composition, and in microbial composition, for soils collected from native P. australis. These latitudinal patterns were weak or absent for soils collected from nearby stands of the exotic S. alterniflora. Climatic and edaphic variables varied across latitude in similar ways in both community types. In P. australis there were strong correlations between community structure and environmental variables, whereas in S. alterniflora these correlations were weak. These results suggest that the invasion of S. alterniflora into the Chinese coastal wetlands has caused profound biotic homogenization of soil communities across latitude. We speculate that the variation in P. australis nematode and microbial communities across latitude is primarily driven by geographic variation in plant traits, but that such variation in plant traits is largely lacking for the recently introduced exotic S. alterniflora. These results indicate that widespread exotic species can homogenize nematode communities at large spatial scales.

RevDate: 2019-03-12

Wen B (2019)

Seed germination ecology of Alexandra palm (Archontophoenix alexandrae) and its implication on invasiveness.

Scientific reports, 9(1):4057 pii:10.1038/s41598-019-40733-0.

Biological invasions are occurring worldwide, causing enormous economic and ecological damage. Early detection and prediction of invasiveness are the most effective measures to reduce its damage. The Alexandra palm (Archontophoenix alexandrae) is a prolific seeder and an alien species widely planted in tropical China. To help understand the invasion risks posed by this species, lab and field experiments on seed germination were conducted. Results show that the seeds only germinate within a temperature range of 20-30 °C and are sensitive to desiccation and high temperature, with seedling inhibition at 35 °C and -0.8 MPa. Complete viability loss was observed after desiccation to water content of 0.17-0.21 g/g or heat treatment for 30 minutes at 60 °C and above. However, appropriate habitats such as the rainforest understory, forest gaps, forest edges, and a rubber plantation are present in Xishuangbanna. Seeds are also frequently consumed by animals; therefore, there is a high potential for Alexandra palm to become an invasive species in Xishuangbanna. Currently, the main barrier to invasion in Xishuangbanna is likely to be the need for seed dispersal into suitable moist, partly shaded, habitats. Understanding the requirements for germination of the Alexandra palm can better inform management strategies for the control of this species.

RevDate: 2019-03-12

O'Loughlin LS, Gooden B, Foster CN, et al (2019)

Invasive shrub re-establishment following management has contrasting effects on biodiversity.

Scientific reports, 9(1):4083 pii:10.1038/s41598-019-40654-y.

Effective control of an invasive species is frequently used to infer positive outcomes for the broader ecosystem. In many situations, whether the removal of an invasive plant is of net benefit to biodiversity is poorly assessed. We undertook a 10-year study on the effects of invasive shrub management (bitou bush, Chrysanthemoides monilifera ssp. rotundata) on native flora and fauna in a eucalypt forest in south-eastern Australia. Bitou bush eradication is a management priority, yet the optimal control regime (combination of herbicide spray and fire) is difficult to implement, meaning managed sites have complex management histories that vary in effectiveness of control. Here we test the long-term response of common biodiversity indicators (species richness, abundance and diversity of native plants, birds, herpetofauna and small mammals) to both the management, and the post-management status of bitou bush (% cover). While average bitou bush cover decreased with management, bitou bush consistently occurred at around half of our managed sites despite control efforts. The relationship between biodiversity and bitou bush cover following management differed from positive, neutral or negative among species groups and indicators. Native plant cover was lower under higher levels of bitou bush cover, but the abundance of birds and small mammals were positively related to bitou bush cover. Evidence suggests that the successful control of an invader may not necessarily result in beneficial outcomes for all components of biodiversity.

RevDate: 2019-03-12
CmpDate: 2019-03-12

Di Vitantonio C, Depalo L, Marchetti E, et al (2018)

Response of the European Ladybird Adalia bipunctata and the Invasive Harmonia axyridis to a Neonicotinoid and a Reduced-Risk Insecticide.

Journal of economic entomology, 111(5):2076-2080.

The spread of the multicolored Asian lady beetle Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) in Europe coincided with the decline of the native Adalia bipunctata (L.) (Coleoptera: Coccinellidae). Both species are predators of aphids in orchards, and differential susceptibility to insecticides used to control fruit pests may contribute to explain the competitive advantage of the invasive over the native species. In this study, the insecticidal activity of imidacloprid and spinetoram was tested on third instars and adults of both ladybird species under laboratory conditions. Insects were exposed to insecticide residues on potted peach plants that were sprayed with the maximum recommended field doses (100 mg/liter for imidacloprid and 66.67 mg/liter for spinetoram). Mortality was scored after short (2 d for both stages) and long (7 and 10 d for adults and larvae, respectively) exposure periods. The susceptibility to the insecticides was very similar for H. axyridis and A. bipunctata. Imidacloprid caused a significant increase in the mortality of both stages of the two species for every exposure period. On the other hand, when exposed to spinetoram residues, larvae and adults of both ladybirds did not show higher mortality than controls after short and long exposure periods. The pest suppression provided by ladybirds, which could be severely hampered by the applications of nonselective pesticides, might be enhanced by the adoption of reduced-risk insecticides, selective for these beneficial insects.

RevDate: 2019-03-12
CmpDate: 2019-03-12

Chase KD, Stringer LD, Butler RC, et al (2018)

Multiple-Lure Surveillance Trapping for Ips Bark Beetles, Monochamus Longhorn Beetles, and Halyomorpha halys (Hemiptera: Pentatomidae).

Journal of economic entomology, 111(5):2255-2263.

Invasions by insects introduced via international trade continue to cause worldwide impacts. Surveillance programs using traps baited with host volatiles and pheromones can detect incursions of nonnative species. We report on two experiments executed to determine if attractants for several insect species can be combined without compromising trap catches and detection ability of target species. In the first experiment, we tested the effect of bark beetle pheromones (plus α-pinene) and trap contact with foliage on trap catches of the brown marmorated stink bug Halyomorpha halys Stål (Hemiptera: Pentatomidae) in traps baited with a mixture of bisabolenes and methyl (E,E,Z)-2,4,6-decatrienoate. Trap capture of H. halys adults was greater in traps not in contact with foliage, and the bark beetle pheromones ipsenol and ipsdienol did not affect trap capture of H. halys. In the second experiment, we tested the effects of multi-lure interactions among the primary host attractants α-pinene and ethanol, and the pheromones monochamol, ipsenol, ipsdienol, lanierone, and the H. halys compounds, on trap captures of various forest and agricultural insect pests. Specifically, we targeted Monochamus spp. (Coleoptera: Cerambycidae), Ips spp. (Coleoptera: Scolytinae) and H. halys. We found that a combination of all lures did not catch significantly lower numbers of Monochamus carolinensis Olivier, Monochamus scutellatus Say (Coleoptera: Cerambycidae), and Ips pini Say (Coleoptera: Scolytidae) than lure combinations missing components although removal of both lanierone and ipsdienol somewhat increased catches of Ips grandicollis Eichhoff (Coleoptera: Curculionidae). Our results support the use of traps baited with a full combination of these attractants in surveillance programs. This should reduce costs and increase detection rates of a wider range of conifer forest pests and H. halys.

RevDate: 2019-03-11

Bajwa AA, Wang H, Chauhan BS, et al (2019)

Effect of elevated carbon dioxide concentration on growth, productivity and glyphosate response of parthenium weed (Parthenium hysterophorus L.).

Pest management science [Epub ahead of print].

BACKGROUND: The rise in atmospheric CO2 has huge impacts on the biology and management of invasive weed species such as Parthenium hysterophorus. This study evaluated the effect of ambient (400 ppm) and elevated (700 ppm) CO2 concentrations on P. hysterophorus growth, reproductive output and response to glyphosate applied at several doses including the recommended dose (800 g a.e. ha-1).

RESULTS: The plants in control treatment (no herbicide) grew taller (41%), produced a larger number of leaves (13%) and flowers (39%), and higher dry biomass (34%) at elevated CO2 as compared to the ambient CO2 . Glyphosate caused significant reduction in chlorophyll content of P. hysterophorus plants grown at both CO2 concentration in a dose-dependent manner. The percentage herbicide injury was relatively less at elevated CO2 as compared to the ambient CO2 at 7 and 14 days after glyphosate application but it was almost similar at 21 days after application. This shows that elevated CO2 might have slowed the translocation of glyphosate initially, but most plants were killed eventually close to 21 days after application. The survival rate was higher under elevated as compared to the ambient CO2 at recommended and lower doses of glyphosate. There was a negligible difference between the two CO2 concentrations for the plant dry biomass reduction over the control treatment.

CONCLUSIONS: P. hysterophorus growth and reproductive potential (indicated by number of flowers) improved significantly by CO2 enrichment but there was little effect on the overall efficacy of glyphosate applied to control this species. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-11

Venegas-Li R, Levin N, Morales-Barquero L, et al (2019)

Global assessment of marine biodiversity potentially threatened by offshore hydrocarbon activities.

Global change biology [Epub ahead of print].

Increasing global energy demands have led to the ongoing intensification of hydrocarbon extraction from marine areas. Hydrocarbon extractive activities pose threats to native marine biodiversity, such as noise, light, and chemical pollution, physical changes to the sea floor, invasive species, and greenhouse gas emissions. Here, we assessed at a global scale the spatial overlap between offshore hydrocarbon activities and marine biodiversity (>25,000 species, nine major ecosystems, and marine protected areas), and quantify the changes over time. We discovered that two-thirds of global offshore hydrocarbon activities occur in areas within the top 10% for species richness, range rarity, and proportional range rarity values globally. Thus, while hydrocarbon activities are undertaken in less than one percent of the ocean's area, they overlap with approximately 85% of all assessed species. Of conservation concern, 4% of species with the largest proportion of their range overlapping hydrocarbon activities are range restricted, potentially increasing their vulnerability to localized threats such as oil spills. While hydrocarbon activities have extended to greater depths since the mid-1990s, we found that the largest overlap is with coastal ecosystems, particularly estuaries, saltmarshes, and mangroves. Furthermore, in most countries where offshore hydrocarbon exploration licensing blocks have been delineated, they do not overlap with marine protected areas (MPAs). Although this is positive in principle, many countries have far more licensing block areas than protected areas, and in some instances, MPA coverage is minimal. These findings suggest the need for marine spatial prioritisation to help limit future spatial overlap between marine conservation priorities and hydrocarbon activities. Such prioritisation can be informed by the spatial and quantitative baseline information provided here. In increasingly shared seascapes, prioritising management actions that set both conservation and development targets could help minimize further declines of biodiversity and environmental changes at a global scale. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-11

Mahon MB, TO Crist (2019)

Invasive earthworm and soil litter response to the experimental removal of white-tailed deer and an invasive shrub.

Ecology [Epub ahead of print].

Recent studies have shown that complex species interactions can regulate above- and below-ground processes in terrestrial systems. Ungulate herbivory and invasive species are known to have strong effects on plant communities in some systems, but their impacts on soil biota and belowground processes are lesser known. Growing evidence suggests white-tailed deer (Odocoileus virginianus) and invasive plants facilitate increased abundance of exotic earthworms in temperate forests of the eastern United States. We conducted an experimental study that manipulated deer access and the presence of an invasive understory shrub in an eastern deciduous forest of southwestern Ohio, USA from 2013 to 2017. Earthworm density and biomass, and standing litter biomass were measured in five paired deer access and exclosure plots, each with a split-plot removal of Amur honeysuckle (Lonicera maackii). Earthworm density declined in response to the experimental exclusion of deer, with earthworm density decreasing over time in the deer exclosure plots relative to deer access plots. Deer exclusion produced greater variation in earthworm species composition relative to access plots. Multivariate analyses indicated that larger earthworms in the genus Lumbricus were associated with deer exclosure plots, while smaller endogeic species were ubiquitous in both treatments. Standing litter biomass decreased over time in the deer-access plots. In contrast, honeysuckle removal had little effect on earthworm density and standing litter biomass. There was an interaction between deer and honeysuckle treatments on earthworm biomass, with honeysuckle removal reducing earthworm biomass when deer were excluded. Our results demonstrate strong effects of herbivores on invasive earthworms and ecosystem processes, but indicate a weaker influence of invasive shrubs. Further, our findings suggest that the effects of deer overabundance in forest ecosystems are potentially reversible with long-term intervention. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-11
CmpDate: 2019-03-11

Goldsmit J, Nudds SH, Stewart DB, et al (2019)

Where else? Assessing zones of alternate ballast water exchange in the Canadian eastern Arctic.

Marine pollution bulletin, 139:74-90.

Mid-ocean ballast water exchange (BWE) is recommended for international vessels to minimize the transfer of nonindigenous species (NIS). When this cannot be accomplished due to safety concerns, alternate ballast water exchange zones (ABWEZ) may be used. A coupled-ice-ocean model with meteorological forcing and particle tracking was used to evaluate the relative risks from BWE along primary shipping routes into Canada's eastern Arctic. Relative risk to receiving habitats from BWE was calculated from the product of likelihood of exposure, likelihood of establishment, and habitat sensitivity to potential NIS. Modelling results indicate that existing ABWEZs in and around Lancaster Sound and Hudson Strait are among the areas of highest relative risk for introductions of NIS via ballast water. The deeper offshore regions of Labrador Sea and Baffin Bay should be considered as alternatives. However, further research is recommended to assess the risks of NIS associated with BWE in the Canadian Arctic.

RevDate: 2019-03-11
CmpDate: 2019-03-11

Cahill P, Tait L, Floerl O, et al (2019)

A portable thermal system for reactive treatment of biofouled internal pipework on recreational vessels.

Marine pollution bulletin, 139:65-73.

Biofouled commercial and recreational vessels are primary vectors for the introduction and spread of marine non-indigenous species (NIS). This study designed and assessed a portable system to reactively treat biofouling in the internal pipework of recreational vessels - a high-risk 'niche area' for NIS that is difficult to access and manage. A novel thermal treatment apparatus was optimised in a series of laboratory experiments performed using scale models of vessel pipework configurations. Treatment effectiveness was validated using the Pacific oyster Magallana gigas, a marine NIS with known resilience to heat. In subsequent field validations on actual recreational vessels, treatment was successfully delivered to high-risk portions of pipework when an effective seal between delivery unit and targeted pipework was achieved and ambient heat loss was minimised. In addition to demonstrating the feasibility of in-water treatment of vessel pipework, the study highlights the importance of robust optimisation and validation of any treatment system intended for biosecurity purposes.

RevDate: 2019-03-11
CmpDate: 2019-03-11

Shen M, Zhu Y, Zhang Y, et al (2019)

Micro(nano)plastics: Unignorable vectors for organisms.

Marine pollution bulletin, 139:328-331.

Micro(nano)plastics, as emerging contaminants, have attracted worldwide attention. Nowadays, the environmental distribution, sources, and analysis methods and technologies of micro(nano)plastics have been well studied and recognized. Nevertheless, the role of micro(nano)plastic particles as vectors for attaching organisms is not fully understood. In this paper, the role of micro(nano)plastics as vectors, and their potential effects on the ecology are introduced. Micro(nano)plastics could 1) accelerate the diffusion of organisms in the environment, which may result in biological invasion; 2) increase the gene exchange between attached biofilm communities, causing the transfer of pathogenic and antibiotic resistance genes; 3) enhance the rate of energy, material and information flow in the environment. Accordingly, the role of microplastics as vectors for organisms should be further evaluated in the future research.

RevDate: 2019-03-10

Magliozzi L, Maselli V, Almada F, et al (2019)

Effect of the algal alkaloid caulerpin on neuropeptide Y (NPY) expression in the central nervous system (CNS) of Diplodus sargus.

Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology pii:10.1007/s00359-019-01322-8 [Epub ahead of print].

Recent studies have suggested that Mediterranean indigenous fish species are affected by bioactive metabolites coming from marine invasive species via food web interactions. In particular, both physiological and behavioural changes in the white sea bream Diplodus sargus were related to caulerpin (CAU), a bisindolic alkaloid particularly abundant in the invasive alga Caulerpa cylindracea, on which the fish actively feed. Dietary administration of CAU decreased aggressiveness in D. sargus, suggesting an anxiolytic-like effect of CAU possibly mediated by endogenous anxiolytic agents. This hypothesis is supported here by the finding of a significant increase of NPY transcriptional expression in the brain of fish fed with CAU enriched food, shedding more light on the neural mechanisms behind the altered behaviour of D. sargus.

RevDate: 2019-03-10

Pais-Costa AJ, Varó I, Martinez-Haro M, et al (2019)

Life history and physiological responses of native and invasive brine shrimps exposed to zinc.

Aquatic toxicology (Amsterdam, Netherlands), 210:148-157 pii:S0166-445X(18)31064-6 [Epub ahead of print].

Although a substantial amount of research exists on pollution and biological invasions, there is a paucity of understanding of how both factors interact. Most studies show that pollution favours the establishment of invasive species, but pollution may also promote local adaptation of native species and prevent the establishment of new incomers. However, evidence for this is extremely limited because most studies focus on successful invasions and very few on cases where an invasion has been resisted. Here we provide evidence of local adaptation of native species to pollution combining life history and physiological data. We focused on the invasion of the North American brine shrimp Artemia franciscana, which is causing a dramatic biodiversity loss in hypersaline ecosystems worldwide, and one of the last native Artemia populations in SW Europe (A. parthenogenetica from the historically polluted Odiel estuary, SW Spain). Life table response experiments were carried out in the laboratory to compare the demographic responses of A. parthenogenetica and a nearby A. franciscana population to long-term Zn exposure (0.2 mg L-1). We also evaluated oxidative stress by measuring antioxidant defences (catalase, glutathione reductase and superoxide dismutase) and lipid peroxidation (thiobarbituric acid reactive substances). A high concentration of Zn induced strong mortality in A. franciscana, which also showed high levels of lipid peroxidation, suggesting relatively poor physiological resistance to pollution compared with A. parthenogenetica. The age at maturity was shorter in A. parthenogenetica, which may be an adaptation to the naturally high mortality rate observed in the Odiel population. Exposure to Zn accelerated age at first reproduction in A. franciscana but not in A. parthenogenetica. In contrast, Zn had a stimulatory effect on offspring production in A. parthenogenetica,which also showed higher reproductive parameters (number of broods, total offspring and offspring per brood) than A. franciscana. Overall, the results of this study strongly suggest that native Artemia from Odiel estuary is locally adapted (at both, reproductive and physiological levels) to Zn contamination and that A. franciscana is highly sensitive. This is a good example of how pollution may play a role in the persistence of the last native Artemia populations in the Mediterranean.

RevDate: 2019-03-10

Cheney C, Esler KJ, Foxcroft LC, et al (2019)

Scenarios for the management of invasive Acacia species in a protected area: Implications of clearing efficacy.

Journal of environmental management, 238:274-282 pii:S0301-4797(19)30272-5 [Epub ahead of print].

In many protected areas in South Africa, invasive Australian Acacia species pose on-going management challenges, perpetuating high long-term management costs. Due to limited availability of resources, conservation actions need to be prioritised within and across Protected Areas (PA). We draw on comprehensive datasets spanning over 20 years from the Table Mountain National Park to model long-term outcomes of clearing Acacia species at different levels of management clearing efficacy. We test a 50 year outlook based on current and 38 incremental levels of management efficacy, ranging from 5 to 100%, to assess under which scenarios a management goal of reducing Acacia density to below 1 plant per hectare for the 22,671 ha protected area is achieved. With the current clearing resources and maximum clearing efficacy (100% control), it would take between 32 and 42 years to attain the management goal. The modelling revealed two main drivers of Acacia persistence. Firstly, germination of seeds added to the seedbank from standing plants made a significantly larger contribution to future clearing requirements than fire stimulated seed germination or the existing (pre-management) seedbank. Secondly the relationship between the number of hectares and management units that could be treated and the efficacy of the treatment was non-linear. When clearing efficacy was decreased from 100% to the current project minimum target of 80% efficacy, the goal was not achieved in all areas, but the area that reached a density of <1 plant per hectare was significantly reduced to 53% of the PA for the simulated 50 years. Results emphasize the need to differentiate between increasing financial resources and increasing efficacy. While increasing financial resources allows for increased effort, this is of little value for Acacia management in the absence of an increase in clearing efficacy, as low quality implementation perpetuates the need for large budgets over time. Conversely, improving efficacy allows for decreased budget requirements over time, allowing fund re-direction to additional areas of alien species management such as the early detection and rapid control of newly introduced species.

RevDate: 2019-03-10

Hui C, DM Richardson (2019)

Network Invasion as an Open Dynamical System: Response to Rossberg and Barabás.

RevDate: 2019-03-09

Richardson KM, Iverson JB, CM Kurle (2019)

Marine subsidies likely cause gigantism of iguanas in the Bahamas.

Oecologia pii:10.1007/s00442-019-04366-4 [Epub ahead of print].

We utilized natural experiment opportunities presented by differential conditions (presence/absence of seabirds and invasive species) on cays in the Bahamas to study whether interisland variations in food resources contributed to gigantism in Allen Cays Rock Iguanas (Cyclura cychlura inornata). We analyzed the stable carbon (δ13C) and nitrogen (δ15N) isotope values from iguana tissues and resources from each island food web to test the predictions that (1) food webs on islands with seabirds exhibit the influence of marine subsidies from seabird guano, whereas those from non-seabird islands do not, and (2) size differences in iguanas among cays were due to either (a) supplemental food availability from mice and/or seabird carcasses killed by barn owls (Tyto alba) and/or (b) access to more nutrient-rich vegetation fertilized by seabird guano. Food web components from the seabird island (Allen Cay) had 5-9‰ higher δ15N values than those on the other cays and Allen Cay plants contained nearly two times more nitrogen. Bayesian stable isotope mixing models indicated that C3 plants dominated iguana diets on all islands and showed no evidence for consumption of mice or shearwaters. The iguanas on Allen Cay were ~ 2 times longer (48.3 ± 11.6 cm) and ~ 6 times heavier (5499 ± 2847 g) than iguanas on other cays and this was likely from marine-derived subsidies from seabird guano which caused an increase in nitrogen concentration in the plants and a resultant increase in the δ15N values across the entire food web relative to non-seabird islands.

RevDate: 2019-03-09

Alexander JM, JM Levine (2019)

Earlier phenology of a nonnative plant increases impacts on native competitors.

Proceedings of the National Academy of Sciences of the United States of America pii:1820569116 [Epub ahead of print].

Adaptation to climate is expected to increase the performance of invasive species and their community-level impacts. However, while the fitness gains from adaptation should, in general, promote invader competitive ability, empirical demonstrations of this prediction are scarce. Furthermore, climate adaptation, in the form of altered timing of life cycle transitions, should affect the phenological overlap between nonnative and native competitors, with potentially large, but poorly tested, impacts on native species persistence. We evaluated these predictions by growing native California grassland plants in competition with nonnative Lactuca serriola, a species that flowers earlier in parts of its nonnative range that are drier than its putative European source region. In common garden experiments in southern California with L. serriola populations differing in phenology, plants originating from arid climates bolted up to 48 d earlier than plants from more mesic climates, and selection favored early flowering, supporting an adaptive basis for the phenology cline. The per capita competitive effects of L. serriola from early flowering populations on five early flowering native species were greater than the effects of L. serriola from later flowering populations. Consequently, the ability of the native species to increase when rare in competition with L. serriola, as inferred from field-parameterized competition models, declined with earlier L. serriola phenology. Indeed, changes to L. serriola phenology affected whether or not one native species was predicted to persist in competition with L. serriola Our results suggest that evolution in response to new climatic conditions can have important consequences for species interactions, and enhance the impacts of biological invasions on natural communities.

RevDate: 2019-03-08

Sherpa S, Blum MGB, Capblancq T, et al (2019)

Unraveling the invasion history of the Asian tiger mosquito in Europe.

Molecular ecology [Epub ahead of print].

Multiple introductions are key features for establishment and persistence of introduced species. However, little is known about the contribution of genetic admixture to the invasive potential of populations. To address this issue, we studied the recent invasion of the Asian tiger mosquito in Europe. Combining genome-wide single nucleotide polymorphisms (SNPs) and historical knowledge using an approximate Bayesian computation framework, we reconstruct the colonization routes and establish the demographic dynamics of invasion. The colonization of Europe involved at least three independent introductions in Albania, North Italy and Central Italy that subsequently acted as dispersal centers throughout Europe. We show that the topology of human transportation networks shaped demographic histories with North Italy and Central Italy being the main dispersal centers in Europe. Introduction modalities conditioned the levels of genetic diversity in invading populations, and genetically diverse and admixed populations promoted more secondary introductions and have spread farther than single-source invasions. This genomic study provides further crucial insights into a general understanding of the role of genetic diversity promoted by modern trade in driving biological invasions. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-08

Kohl PA, Brossard D, Scheufele DA, et al (2019)

Public views about gene editing wildlife for conservation.

Conservation biology : the journal of the Society for Conservation Biology [Epub ahead of print].

Developments in CRISPR-based gene-editing technologies have generated a growing number of proposals to gene edit populations of wildlife to meet conservation goals. These include proposals to use wildlife genome editing as a response to the spread of invasive species and other threats to biodiversity. As these proposals attract greater attention, controversies have emerged among scientists and stakeholder groups over potential consequences and ethical implications. Stakeholders on both sides of debates acknowledge that responsible governance cannot be developed without consulting broader publics. Yet little effort has been made to systematically assess public understandings and beliefs in relation to this new area of applied genetic engineering. In this study, we analyze the results of a survey of American adults (n = 1,600) to examine concerns about gene editing wildlife and how those concerns are shaped by cultural dispositions toward science and beliefs about the appropriateness of intervening into nature at the genetic level. On average, people perceived more risk than benefit in using these tools. Large majorities also agreed that gene editing wildlife could be easily used for the wrong purposes. When evaluating the moral acceptability of gene editing wildlife, people evaluate applications to improve survival in endangered wildlife as more morally acceptable than applications to reduce or eliminate a wildlife population. People who tend to more strongly believe in the authority of scientific knowledge expressed more favorable views of the benefits, risks, and moral acceptability of gene editing wildlife. On the other hand, people who tended to think gene editing wildlife inappropriately intervenes in nature expressed more concern about risks and moral acceptability and were more skeptical of the benefits. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-08

Mu X, Xu M, Ricciardi A, et al (2019)

The influence of warming on the biogeographic and phylogenetic dependence of herbivore-plant interactions.

Ecology and evolution, 9(4):2231-2241 pii:ECE34918.

Evolutionary experience and the phylogenetic relationships of plants have both been proposed to influence herbivore-plant interactions and plant invasion success. However, the direction and magnitude of these effects, and how such patterns are altered with increasing temperature, are rarely studied. Through laboratory functional response experiments, we tested whether the per capita feeding efficiency of an invasive generalist herbivore, the golden apple snail, Pomacea canaliculata, is dependent on the biogeographic origin and phylogenetic relatedness of host plants, and how increasing temperature alters these dependencies. The feeding efficiency of the herbivore was highest on plant species with which it had no shared evolutionary history, that is, novel plants. Further, among evolutionarily familiar plants, snail feeding efficiency was higher on those species more closely related to the novel plants. However, these biogeographic dependencies became less pronounced with increasing temperature, whereas the phylogenetic dependence was unaffected. Collectively, our findings indicate that the susceptibility of plants to this invasive herbivore is mediated by both biogeographic origin and phylogenetic relatedness. We hypothesize that warming erodes the influence of evolutionary exposure, thereby altering herbivore-plant interactions and perhaps the invasion success of plants.

RevDate: 2019-03-07

Trapero-Casas A, Rodríguez-Tello A, WJ Kaiser (2000)

Lupins, a New Host of Phytophthora erythroseptica.

Plant disease, 84(4):488.

Several lupin (Lupinus) species are native to southern Spain (2). The white lupin, Lupinus albus L., is the most important crop, and its seeds are used for human consumption and animal feed. Accessions of three indigenous species, L. albus, L. angustifolius L., and L. luteus L., and an introduced species from South America, L. mutabilis Sweet, were planted during October in replicated yield trials in acidic soils (pH 6.5) in the Sierra Morena Mountains (elevation 350 m) north of Córdoba. Root and crown rot disease was widespread and very serious on the indigenous lupins, particularly in several patches of white lupin cultivars. Infected plants were devoid of feeder rootlets, and the tap roots, crowns, and lower stems were necrotic and turned dark brown to black. Rotted roots were colonized heavily by fungal oospores. Many affected plants wilted and died before flowering. A Phytophthora sp. was isolated consistently from the necrotic roots and crowns of symptomatic white lupins. The same fungus also was isolated from the necrotic root tissues of the other indigenous lupin species. Isolates of the fungus from diseased white lupins were homothallic and produced oospores rapidly and abundantly on corn meal and V8 agars. Antheridia were amphigynous, and aplerotic oospores ranged from 22 to 32 μm (average 27 μm). Nonpapillate, ovoidobpyriform sporangia were produced only in water on simple sympodial sporangiophores. Cultures on V8 agar grew at 5 to 30°C (optimum ≈25°C). The species was identified as Phytophthora erythroseptica Pethybr. based on morphology of oospores, sporangia, and other cultural characteristics (1). Koch's postulates were fulfilled by planting seeds of white lupin cv. Multulupa in sterile potting soil infested with a blended culture on V8 agar from a white lupin isolate of P. erythroseptica and reisolating the fungus after 28 days from lesions that developed on the roots and crowns of inoculated plants incubated in a greenhouse at 16 to 26°C. The fungus was not isolated from white lupins seeded in potting soil inoculated with sterile V8 agar. In pathogenicity tests, two isolates of P. erythroseptica from white lupins caused severe symptoms on the roots and crowns of inoculated white lupin cv. Multulupa similar to those observed on white lupins naturally infected in field trials. These isolates also caused root and crown rots on inoculated L. luteus and L. angustifolius. The fungus did not infect the roots or crowns of tarwi (L. mutabilis cv. SCG 20), alfalfa (Medicago sativa cv. Moapa), bean (Phaseolus vulgaris cv. Contender), chickpea (Cicer arietinum cv. Blanco Lechoso), faba bean (Vicia faba cv. Arboleda), lentil (Lens culinaris cv. local), pea (Pisum sativum cv. Lancet), soybean (Glycine max cv. Akashi), or subterranean clover (Trifolium subterraneum cv. Seaton-park). The tests were repeated, and the results were similar. This is the first report of P. erythroseptica infecting Lupinus spp. References: (1) D. C. Erwin and O. K. Ribeiro. 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN. (2) B. Valdés et al. 1987. Flora Vascular de Andalucía Occidental. Ketres, Barcelona, Spain.

RevDate: 2019-03-08
CmpDate: 2019-03-08

Aladin NV, Gontar VI, Zhakova LV, et al (2019)

The zoocenosis of the Aral Sea: six decades of fast-paced change.

Environmental science and pollution research international, 26(3):2228-2237.

During the last six decades, the water level of the Aral Sea, once one of the largest lakes in the world, has experienced a major human-driven regression followed by significant changes in salinity. These fast-paced alterations were initiated by the diversion of two rivers-the Amu Darya and Syr Darya-key players in the regulation of the water balance of the Aral Sea. Consequently, biological modifications took place leading to severe changes of the zoocenosis. This paper reviews the changes that have affected communities of fish and aquatic invertebrates in the Aral Sea since the 1950s. The reported alterations in biodiversity not only represent a natural response to a decrease in water level and a subsequent increase in salinity but also effects of non-native species introduction. The future prospects for invertebrates and fish in the Aral Sea, assuming that initiated restoration work is continued, are also discussed in this paper.

RevDate: 2019-03-08
CmpDate: 2019-03-08

Black A, Waipara N, M Gerth (2018)

Calling time on New Zealand's oldest tree species.

Nature, 561(7722):177.

RevDate: 2019-03-07

Anderson RB (2019)

Human traffic and habitat complexity are strong predictors for the distribution of a declining amphibian.

PloS one, 14(3):e0213426 pii:PONE-D-18-09442.

Invasive species and habitat modification threaten California's native pond-breeding amphibians, including the federally threatened California Red-legged Frog (Rana draytonii). The relative contributions of invasive species, including the American Bullfrog (Lithobates catesbeianus), and of habitat changes to these declines are disputed. I conducted a field study over several years in central California to examine the presence/absence of these two species at 79 breeding ponds to determine the predictive role for occupancy of factors including vegetation, pond characteristics, and measures of human activity. I used a boosted regression tree approach to determine the relative value of each predictor variable. Increased measures of human activity, especially proximity to trails and roads, were the best predictors for the absence of California Red-legged Frogs and California Newts. Historical factors and habitat conditions were associated with the extent and spread of the American Bullfrog. The extent and complexity of aquatic macrophytes and pond surface area were good predictors for the presence of these and other amphibian species. Surprisingly, invasive species played a relatively small role in predicting pond occupancy by the native species. These findings can inform conservation and restoration efforts for California Red-legged Frogs, which apparently persist best in small vegetated ponds in areas of low human disturbance.

RevDate: 2019-03-07

Helmer L, Farrell P, Hendy I, et al (2019)

Active management is required to turn the tide for depleted Ostrea edulis stocks from the effects of overfishing, disease and invasive species.

PeerJ, 7:e6431 pii:6431.

The decline of the European oyster Ostrea edulis across its biogeographic range has been driven largely by over-fishing and anthropogenic habitat destruction, often to the point of functional extinction. However, other negatively interacting factors attributing to this catastrophic decline include disease, invasive species and pollution. In addition, a relatively complex life history characterized by sporadic spawning renders O. edulis biologically vulnerable to overexploitation. As a viviparous species, successful reproduction in O. edulis populations is density dependent to a greater degree than broadcast spawning oviparous species such as the Pacific oyster Crassostrea (Magallana) gigas. Here, we report on the benthic assemblage of O. edulis and the invasive gastropod Crepidula fornicata across three actively managed South coast harbors in one of the few remaining O. edulis fisheries in the UK. Long-term data reveals that numbers of O. edulis sampled within Chichester Harbour have decreased by 96%, in contrast numbers of C. fornicata sampled have increased by 441% over a 19-year period. The recent survey data also recorded extremely low densities of O. edulis, and extremely high densities of C. fornicata, within Portsmouth and Langstone Harbours. The native oyster's failure to recover, despite fishery closures, suggests competitive exclusion by C. fornicata is preventing recovery of O. edulis, which is thought to be due to a lack of habitat heterogeneity or suitable settlement substrate. Large scale population data reveals that mean O. edulis shell length and width has decreased significantly across all years and site groups from 2015 to 2017, with a narrowing demographic structure. An absence of juveniles and lack of multiple cohorts in the remaining population suggests that the limited fishing effort exceeds biological output and recruitment is poor. In the Langstone & Chichester 2017 sample 98% of the population is assigned to a single cohort (modal mean 71.20 ± 8.78 mm, maximum length). There is evidence of small scale (<5 km) geographic population structure between connected harbors; the 2015 Portsmouth and Chichester fishery populations exhibited disparity in the most frequent size class with 36% within 81-90 mm and 33.86% within 61-70 mm, respectively, the data also indicates a narrowing demographic over a short period of time. The prevalence of the disease Bonamiosis was monitored and supports this microgeographic population structure. Infection rates of O. edulis by Bonamia ostreae was 0% in Portsmouth Harbor (n = 48), 4.1% in Langstone (n = 145) and 21.3% in Chichester (n = 48) populations. These data collectively indicate that O. edulis is on the brink of an ecological collapse within the Solent harbors. Without effective intervention to mitigate the benthic dominance by C. fornicata in the form of biologically relevant fishery policy and the management of suitable recruitment substrate these native oyster populations could be lost.

RevDate: 2019-03-07

Lu-Irving P, Harenčár JG, Sounart H, et al (2019)

Native and Invading Yellow Starthistle (Centaurea solstitialis) Microbiomes Differ in Composition and Diversity of Bacteria.

mSphere, 4(2): pii:4/2/e00088-19.

Invasive species could benefit from being introduced to locations with more favorable species interactions, including the loss of enemies, the gain of mutualists, or the simplification of complex interaction networks. Microbiomes are an important source of species interactions with strong fitness effects on multicellular organisms, and these interactions are known to vary across regions. The highly invasive plant yellow starthistle (Centaurea solstitialis) has been shown to experience more favorable microbial interactions in its invasions of the Americas, but the microbiome that must contribute to this variation in interactions is unknown. We sequenced amplicons of 16S rRNA genes to characterize bacterial community compositions in the phyllosphere, ectorhizosphere, and endorhizosphere of yellow starthistle plants from seven invading populations in California, USA, and eight native populations in Europe. We tested for the differentiation of microbiomes by geography, plant compartment, and plant genotype. Bacterial communities differed significantly between native and invading plants within plant compartments, with consistently lower diversity in the microbiome of invading plants. The diversity of bacteria in roots was positively correlated with plant genotype diversity within both ranges, but this relationship did not explain microbiome differences between ranges. Our results reveal that these invading plants are experiencing either a simplified microbial environment or simplified microbial interactions as a result of the dominance of a few taxa within their microbiome. Our findings highlight several alternative hypotheses for the sources of variation that we observe in invader microbiomes and the potential for altered bacterial interactions to facilitate invasion success.IMPORTANCE Previous studies have found that introduced plants commonly experience more favorable microbial interactions in their non-native range, suggesting that changes to the microbiome could be an important contributor to invasion success. Little is known about microbiome variation across native and invading populations, however, and the potential sources of more favorable interactions are undescribed. Here, we report one of the first microbiome comparisons of plants from multiple native and invading populations, in the noxious weed yellow starthistle. We identify clear differences in composition and diversity of microbiome bacteria. Our findings raise new questions about the sources of these differences, and we outline the next generation of research that will be required to connect microbiome variation to its potential role in plant invasions.

RevDate: 2019-03-07
CmpDate: 2019-03-07

Ibañez-Justicia A, Poortvliet PM, CJM Koenraadt (2019)

Evaluating perceptions of risk in mosquito experts and identifying undocumented pathways for the introduction of invasive mosquito species into Europe.

Medical and veterinary entomology, 33(1):78-88.

In several reported cases of the entry of invasive mosquito species (IMSs) into Europe, the introduction was associated with a specific pathway of introduction or dispersal. The identification of potential pathways for the introduction of IMSs and evaluations of the importance of the different pathways are key to designing proper surveillance strategies to promptly detect and control introductions in non-infested areas. The main goals of the present study were to identify other, previously undocumented, pathways of introduction into Europe, and to identify mosquito experts' perceptions regarding control measures against IMS introductions via different documented pathways. At the European Mosquito Control Association (EMCA) conference in Montenegro in March 2017, a questionnaire was distributed among meeting participants to collect expert data. Results showed that ground transportation (by cars, trucks, etc.), passive natural dispersal and the shipping of used tyres are perceived as the most likely pathways. Introduction via aircraft did not appear to be well known and was not perceived as probable. This study shows that there were no pathways unknown to European experts that could lead to cryptic introductions into the experts' countries. Furthermore, the findings demonstrated that the perceived efficacy of surveillance and control is key to overcoming the constraints experienced and to supporting the implementation of actions against introductions.

RevDate: 2019-03-07
CmpDate: 2019-03-07

Klobučar A, Lipovac I, Žagar N, et al (2019)

First record and spreading of the invasive mosquito Aedes japonicus japonicus (Theobald, 1901) in Croatia.

Medical and veterinary entomology, 33(1):171-176.

Aedes (Hulecoeteomyia) japonicus japonicus (Theobald, 1901) has recently established across North America and Central Europe. A 3-year survey was conducted in northwestern Croatian regions from 2013 to 2015 using mosquito ovitraps at possible points of entry and house yards, occasionally complemented by larval collections from cemetery vases. In the first year, the survey investigated the county bordering Slovenia, where the first detection of Ae. j. japonicus had taken place on 28 August 2013. During the next 2 years, Ae. j. japonicus was detected in this area from early May until late October. In 2015, several counties further to the east were included in the survey, leading to the detection of Ae. j. japonicus approximately 100 km eastward from the initially surveyed region. Given a moderate continental climate and homogeneous climatic conditions in this part of Europe, the eastward spread of Ae. j. japonicus can be expected to continue.

RevDate: 2019-03-06

Liang W, Tran L, Wiggins GJ, et al (2019)

Determining Spread Rate of Kudzu Bug (Hemiptera: Plataspidae) and Its Associations With Environmental Factors in a Heterogeneous Landscape.

Environmental entomology pii:5370310 [Epub ahead of print].

By the end of 2017, kudzu bug was reported in 652 counties in the United States since it was first observed in Georgia in 2009. Modeling its invasion dynamics is valuable to guide management through early detection and prevention of further invasion. Herein, we initially estimated the spread rate of kudzu bug with county-level invasion records and then determined important spatial factors affecting its spread during years 2010-2016. As kudzu bug infests a large heterogeneous area and shows asymmetric spread, we first utilized spatially constrained clustering (SCC), an unsupervised machine learning method, to divide the infested area into eight spatially contiguous and environmentally homogenous neighborhoods. We then used distance regression and boundary displacement methods to estimate the spread rates in all neighborhoods. Finally, we applied multiple regression to determine spatial factors influencing the spread of kudzu bug. The average spread rate reached 76 km/yr by boundary displacement method; however, the rate varied largely among eight neighborhoods (45-144 km/yr). In the southern region of the infested area, host plant density and wind speed were positively associated with the spread rate, whereas mean annual temperature, precipitation in the fall, and elevation had inverse relationships. In the northern region, January minimum temperature, wind speed, and human population density showed positive relationships. This study increases the knowledge on the spread dynamics of kudzu bug. Our research highlights the utility of SCC to determine natural clustering in a large heterogeneous region for better modeling of local spread patterns and determining important factors affecting the invasions.

RevDate: 2019-03-06

Bridi R, Atala E, Pizarro PN, et al (2019)

Honeybee Pollen Load: Phenolic Composition and Antimicrobial Activity and Antioxidant Capacity.

Journal of natural products [Epub ahead of print].

Honeybee pollen loads result from the agglutination of pollen grains and salivary secretions of bees. The potential use of honeybee pollen as a food supplement greatly depends on its chemical composition, which varies depending on the botanical and geographical origin of the pollen grains. This study aimed to characterize the botanical origin, chemical composition, and antioxidant and antibacterial activities of honeybee pollen from the V Region of Chile. The introduced species Brassica rapa and Eschscholzia californica predominated in the bee pollen analyzed. The honeybee pollen extracts showed antioxidant and antibacterial properties, specifically against the pathogenic microorganism Streptococcus pyogenes. Quercetin and myricetin were found in all samples in large concentrations. The separation of pollen loads from a multifloral sample demonstrated that E. californica pollen loads are responsible for antibacterial activity. This sample also showed a high concentration of quercetin (304.8 mg/100 g of bee pollen). Based on the present results, honeybee pollen from the V Region of Chile has been found to exhibit antioxidant and antimicrobial activities. Furthermore, it is proposed to use quercetin as a quality indicator for honeybee pollen from this region of Chile. These results should help establish better quality control criteria for Chilean honeybee pollen and its potential use as a functional ingredient.

RevDate: 2019-03-06

Levin SC, Crandall RM, TM Knight (2019)

Population projection models for 14 alien plant species in the presence and absence of above-ground competition.

Ecology [Epub ahead of print].

Plant population ecologists strive to understand how environmental drivers influence demographic vital rates and thus population dynamics. Hundreds of studies have collected demographic data and used matrix- and/or integral projection models to quantify lifetime fitness and population dynamics of plants. However, most of these studies have focused on native plant species, and there is a need for more studies on alien plants. Further, few studies on alien plants have experimentally manipulated environmental drivers in order to understand the mechanisms that allow alien plant species to have positive population growth. A synthetic understanding of the population dynamics of alien plant species will only be achieved if ecologists collect demographic data on many plant species and environments and provide the demographic data and model structure in a data archive for future comparisons and meta-analyses. Invasive alien species are a social, economic and ecological issue that has become increasingly important in an increasingly globalized world. Researchers continue to forecast impacts and prevent new introductions by seeking a robust understanding of drivers of invasive species success and failure. Researchers have hypothesized that competitive differences may play a key role in determining alien species success in novel environments. Studies that experimentally manipulate competitors while quantifying demography provide mechanistic insight into species' responses to competition. To date, nearly all field manipulations of competition that measure plant demography and population dynamics have focused on native plant species. The data we provide here aims to address this gap in our knowledge for alien plant species. We present raw data and population projection models for 14 alien plant species in eastern Missouri, USA. We sampled under ambient conditions and with all individuals of non-focal species removed from the community, allowing us to project population dynamics in the presence and absence of competition. We have also included the data quantifying how much biomass we removed at the plot level during each removal procedure and data from our germination experiment. This article is protected by copyright. All rights reserved.

RevDate: 2019-03-06
CmpDate: 2019-03-06

Zhao B, Xue S, Zhu W, et al (2019)

Development of microsatellite markers for the Siberian weasel Mustela sibirica.

Genes & genetic systems, 93(6):255-258.

The Siberian weasel (Mustela sibirica) is widely distributed in mainland Asia, but its introduction into Japan and subsequent expansion have affected the Japanese weasel (M. itatsi). To provide a useful tool for population genetic studies and control of M. sibirica, we developed 10 polymorphic microsatellite markers. Among 40 individuals of M. sibirica collected in Hubei Province, China, the number of alleles per locus varied from 2 to 19, with the observed heterozygosity ranging from 0.050 to 1.000 and the expected heterozygosity ranging from 0.049 to 0.920. None of the loci deviated from Hardy-Weinberg equilibrium. These markers will be useful in further studies investigating the population structure and natural history of M. sibirica, and may thus provide new insights for the efficient management of this species.

RevDate: 2019-03-06
CmpDate: 2019-03-06

Keeling MJ, Franklin DN, Datta S, et al (2017)

Predicting the spread of the Asian hornet (Vespa velutina) following its incursion into Great Britain.

Scientific reports, 7(1):6240.

The yellow-legged or Asian hornet (Vespa velutina) is native to South-East Asia, and is a voracious predator of pollinating insects including honey bees. Since its accidental introduction into South-Western France in 2004, V. velutina has spread to much of western Europe. The presence of V. velutina in Great Britain was first confirmed in September 2016. The likely dynamics following an initial incursion are uncertain, especially the risk of continued spread, and the likely success of control measures. Here we extrapolate from the situation in France to quantify the potential invasion of V. velutina in Great Britain. We find that, without control, V. velutina could colonise the British mainland rapidly, depending upon how the Asian hornet responds to the colder climate in Britain compared to France. The announcement that a second hornet had been discovered in Somerset, increases the chance that the invasion first occurred before 2016. We therefore consider the likely site of first invasion and the probabilistic position of additional founding nests in late 2016 and early 2017. Given the potential dispersion of V. velutina, we conclude that vigilance is required over a large area to prevent the establishment of this threat to the pollinator population.

RevDate: 2019-03-04

Molina CV, Heinemann MB, Kierulff C, et al (2019)

Leptospira spp., rotavirus, norovirus, and hepatitis E virus surveillance in a wild invasive golden-headed lion tamarin (Leontopithecus chrysomelas; Kuhl, 1820) population from an urban park in Niterói, Rio de Janeiro, Brazil.

American journal of primatology [Epub ahead of print].

The world currently faces severe biodiversity losses caused by anthropogenic activities such as deforestation, pollution, the introduction of exotic species, habitat fragmentation, and climate changes. Disease ecology in altered environments is still poorly understood. The golden-headed lion tamarin (GHLT, Leontopithecus chrysomelas) is an endangered species that became invasive in an urban park in Niterói, Rio de Janeiro, Brazil. The initially few invasive GHLT individuals became hundreds, adapted to living in proximity to humans and domestic animals. These GHLTs were captured as part of a conservation project; some animals were translocated to Bahia and some were kept in captivity. This study tested 593 GHLT for Leptospira serology; 100 and 95 GHLT for polymerase chain reaction (PCR) toLeptospira and hepatitis E virus genotype 3 (HEV-3), respectively, and 101 familiar groups for PCR to viruses (rotavirus A, norovirus GI and GII, and HEV-3). One animal had antibodies for Leptospira serovar Shermani and another for serovar Hebdomadis. One saprophyticLeptospira was found by the 16S PCR and sequencing. Viruses were not detected in samples tested. Findings suggest that the epidemiological importance of such pathogens in this GHLT population is either low or nonexistent. These data are important to understand the local disease ecology, as well as monitoring a translocation project, and to contribute data for species conservation.

RevDate: 2019-03-04

DeLong JP, J Belmaker (2019)

Ecological pleiotropy and indirect effects alter the potential for evolutionary rescue.

Evolutionary applications, 12(3):636-654 pii:EVA12745.

Invading predators can negatively affect naïve prey populations due to a lack of evolved defenses. Many species therefore may be at risk of extinction due to overexploitation by exotic predators. Yet the strong selective effect of predation might drive evolution of imperiled prey toward more resistant forms, potentially allowing the prey to persist. We evaluated the potential for evolutionary rescue in an imperiled prey using Gillespie eco-evolutionary models (GEMs). We focused on a system parameterized for protists where changes in prey body size may influence intrinsic rate of population growth, space clearance rate (initial slope of the functional response), and the energetic benefit to predators. Our results show that the likelihood of rescue depends on (a) whether multiple parameters connected to the same evolving trait (i.e., ecological pleiotropy) combine to magnify selection, (b) whether the evolving trait causes negative indirect effects on the predator population by altering the energy gain per prey, (c) whether heritable trait variation is sufficient to foster rapid evolution, and (d) whether prey abundances are stable enough to avoid very rapid extinction. We also show that when evolution fosters rescue by increasing the prey equilibrium abundance, invasive predator populations also can be rescued, potentially leading to additional negative effects on other species. Thus, ecological pleiotropy, indirect effects, and system dynamics may be important factors influencing the potential for evolutionary rescue for both imperiled prey and invading predators. These results suggest that bolstering trait variation may be key to fostering evolutionary rescue, but also that the myriad direct and indirect effects of trait change could either make rescue outcomes unpredictable or, if they occur, cause rescue to have side effects such as bolstering the populations of invasive species.

RevDate: 2019-03-04

Senn HV, Ghazali M, Kaden J, et al (2019)

Distinguishing the victim from the threat: SNP-based methods reveal the extent of introgressive hybridization between wildcats and domestic cats in Scotland and inform future in situ and ex situ management options for species restoration.

Evolutionary applications, 12(3):399-414 pii:EVA12720.

The degree of introgressive hybridization between the Scottish wildcat and domestic cat has long been suspected to be advanced. Here, we use a 35-SNP-marker test, designed to assess hybridization between wildcat and domestic cat populations in Scotland, to assess a database of 295 wild-living and captive cat samples, and test the assumptions of the test using 3,097 SNP markers generated independently in a subset of the data using ddRAD. We discovered that despite increased genetic resolution provided by these methods, wild-living cats in Scotland show a complete genetic continuum or hybrid swarm structure when judged against reference data. The historical population of wildcats, although hybridized, clearly groups at one end of this continuum, as does the captive population of wildcats. The interpretation of pelage scores against nuclear genetic data continues to be problematic. This is probably because of a breakdown in linkage equilibrium between wildcat pelage genes as the two populations have become increasingly mixed, meaning that pelage score or SNP score alone is poor diagnostic predictors of hybrid status. Until better tools become available, both should be used jointly, where possible, when making management decisions about individual cats. We recommend that the conservation community in Scotland must now define clearly what measures are to be used to diagnose a wildcat in the wild in Scotland, if future conservation action is to be effective.

RevDate: 2019-03-04

Scapin P, Ulbano M, Ruggiero C, et al (2019)

Surgical sterilization of male and female grey squirrels (Sciurus carolinensis) of an urban population introduced in Italy.

The Journal of veterinary medical science [Epub ahead of print].

We report a successful surgical sterilization procedure for population control of 324 male and female free-ranging grey squirrels (Sciurus carolinensis) in Genoa (Italy). We describe the clinical procedure from the trapping of the animals to their surgical sterilization and release in another part of the city. Live-trapped squirrels were transported to the veterinary clinic within 1-2 hr of capture and maintained in a hospitalization room reserved for them. The waiting period before surgery was kept below 12 hr. The developed procedure has resulted in a survival of 94% of trapped squirrels from surgery to animal release. Sterilized squirrels started to feed in a very short time (1.0-1.5 hr), and after 2-3 days, it was possible to release them in a new area. Amoxicillin was used as a long-acting postoperative antibiotic to reduce the period of captivity. The successful surgical procedure described here can provide an important additional tool for the management of introduced populations of squirrels. We showed that the surgical sterilization of some hundred squirrels is clinically possible and could be included in management strategies aimed at removing critical populations of these species. Moreover, the data allow dosages and operational times in order to provide economic viability assessment of future population control measures.

RevDate: 2019-03-04

Joyce PWS, Dickey JWE, Cuthbert RN, et al (2019)

Using functional responses and prey switching to quantify invasion success of the Pacific oyster, Crassostrea gigas.

Marine environmental research pii:S0141-1136(19)30022-4 [Epub ahead of print].

Invasive alien species continue to proliferate and cause severe ecological impacts. Functional responses (FRs) have shown excellent utility in predicting invasive predator success, however, their use in predicting invasive prey success is limited. Here, we assessed invader success by quantifying FRs and prey switching patterns of two native predators, the common sea star, Asterias rubens, and the green crab, Carcinus maenas, towards native blue mussels, Mytilus edulis, and invasive Pacific oysters, Crassostrea gigas. Asterias displayed destabilising type II FRs, whereas Carcinus displayed stabilising type III FRs towards both prey species. Both predators exhibited greater search efficiencies and maximum feeding rates towards native compared to invasive prey. Both predators disproportionately consumed native mussels over invasive oysters when presented simultaneously, even when native mussels were rare in the environment, therefore indicating negligible prey switching. We demonstrate that invasion success may be mediated through differential levels of biotic resistance exerted by native predators.

RevDate: 2019-03-04
CmpDate: 2019-03-04

Whitehead ABR, Butcher GD, Walden HS, et al (2018)

Burden of exposure to infectious bursal disease virus, infectious bronchitis virus, Newcastle disease virus, Mycoplasma gallisepticum, and intestinal parasites in introduced broiler chickens on the Galapagos.

PloS one, 13(9):e0203658.

Diseases in introduced broilers can possibly spill over to wild birds on the Galapagos. Knowledge about the current burden of exposure to pathogens in broilers on the Galapagos is very limited. The objective of the study reported here was to measure the burden of exposure to infectious bursal disease virus (IBDV), infectious bronchitis virus (IBV), Newcastle disease virus (NDV), Mycoplasma gallisepticum (MG), and intestinal parasites in a sample of broiler chickens on 13 farms on Santa Cruz Island and San Cristobal Island in July 2017. Blood serum samples were tested for detection of antibodies to IBDV, IBV, NDV, and MG by using an IDEXX Enzyme-linked Immunosorbent Assay. In addition, fecal samples and pen bedding environmental samples were processed and analyzed for diagnosis of intestinal parasite eggs under a compound light microscope. The frequency of seropositive broilers to IBDV was 74/130 or 56% (95% CI = 48, 65%), to IBV was 27/130 or 20% (14, 28%), and to NDV was 1/130 or 0.7% (0.1, 4%). All broilers tested negative to MG antibodies. Eimeria spp. infection was common in study broilers. Finally, we observed interaction between broiler chickens and wild birds (finches) inside broiler pens, as well as the presence of backyard chickens inside property limits of study farms. This study produced evidence that exposure to IBDV, IBV, and intestinal parasites in broilers on Santa Cruz Island and San Cristobal Island is important. Study results are relevant because (i) they provide new baseline data on the burden of exposure to avian pathogens in broiler farms, (ii) justify the need to verify standard operating procedures in hatcheries that supply (non-vaccinated) day-old chicks to the Galapagos and (iii) to implement enhanced biosecurity standards on broiler chicken farms to mitigate risk of disease transmission between broilers, backyard poultry, and wild birds on the Galapagos.

RevDate: 2019-03-04
CmpDate: 2019-03-04

Zhang L, Wang S, Liu S, et al (2018)

Perennial forb invasions alter greenhouse gas balance between ecosystem and atmosphere in an annual grassland in China.

The Science of the total environment, 642:781-788.

Grassland ecosystems are sensitive to invasions by plants from other functional groups which can alter soil greenhouse gas (GHG) fluxes. However, the effects of plant invasion on net GHG exchanges between soils and the atmosphere, plant production, and global warming potential (GWP) of annual grasslands is poorly understood. To evaluate the impacts of perennial forb invasions on GHG budgets of an annual grassland in China, we measured soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes over two years in replicated invaded (dominated by Alternanthera philoxeroides or Solidago canadensis) and non-invaded (dominated by the annual grass Eragrostis pilosa or the annual forb Sesbania cannabina) field sites. On average, soil CO2 and N2O emissions from invaded sites were 30% and 76% higher, respectively, relative to sites dominated by native species. Emissions of N2O and CO2 were especially high in Solidago and Alternanthera dominated sites, respectively. Soil CH4 emissions did not vary with plant species. On average, total biomass C of invaded sites was higher than that of the native dominated sites but this reflected the high C in Solidago dominated sites. Global warming potential (GWP) was increased by Alternanthera invasions and decreased by Solidago invasions. Plant invasions affected GWP of these annual grasslands through higher emissions of some GHGs but also sometimes higher biomass C. Together, this suggests that perennial forb invasions could change the net source or sink role of annual grasslands for GHG budgets, but the effects on GWP vary among species depending on GHG responses and C storage.

RevDate: 2019-03-04
CmpDate: 2019-03-04

De Jong GL, NL Fowler (2018)

Duration of propagule pressure affects non-native plant species abundances.

American journal of botany, 105(2):197-206.

PREMISE OF THE STUDY: Invasions by non-native species are known to be related to present propagule pressure (e.g., the number of non-native seeds arriving in a site each year). However, previous studies have mostly ignored the potential effects of the length of time that a site has experienced propagule pressure. This study is novel in studying past as well as present propagule pressure and in demonstrating the importance of past propagule pressure.

METHODS: We tested the importance of past and present propagule pressure in three plant communities in central Texas to quantify relationships between variables representing past and present propagule pressure, other environmental variables, and the abundance of non-native and native woody plant species.

KEY RESULTS: Duration of propagule pressure predicted non-native species richness. Sites had greater non-native species richness if they were nearer to development (houses, roads) and if nearby development was older. While mesic woodlands had the most native species, streamside woodlands had the most non-native species.

CONCLUSIONS: First, future studies of non-native invasions would benefit from including past as well as present propagule pressure. If past propagule pressure is not considered, its effects may be wrongly ascribed to present propagule pressure. Second, the non-native species in this study are widely used in landscaping, and development age reflects the years that landscaping has been present nearby. As xeriscaping becomes more common, streamside woodlands may someday not have the highest non-native species richness: the new drought-tolerant landscaping plants may be better invaders of drier sites than their predecessors.

RevDate: 2019-03-02

Hill JH, Alleman R, Hogg DB, et al (2001)

First Report of Transmission of Soybean mosaic virus and Alfalfa mosaic virus by Aphis glycines in the New World.

Plant disease, 85(5):561.

The recent discovery of the soybean aphid, Aphis glycines Matsamura, in the North Central region of the United States is significant because it is the first time that a soybean-colonizing aphid has been detected in the New World. Although the aphid has the potential to cause physiological loss of up to 52% on soybeans (4), it can also transmit Soybean mosaic virus (SMV). Transmission of Alfalfa mosaic virus (AMV) has not been reported. SMV, and less commonly AMV, are found in soybeans in the North Central states and are transmitted by numerous aphids in a nonpersistent manner (2; Grau, unpublished). For SMV, potential exists for specificity of transmission between virus strain and aphid species (3). For these reasons, it was important to determine if an endemic isolate of these viruses could be transmitted by this introduced species of aphid in the North Central region. Transmission experiments were conducted as described (3), using 3, 5, and 10 aphids per plant. Ten plants of the soybean cultivar Williams 82 were used for each treatment. To preclude confounding results by possible seed transmission, plants used in all tests were grown from seeds harvested from virus-indexed plants grown in the greenhouse. For experiments involving SMV, the aphid-transmissible field isolate Al5 (GeneBank Accession no. AF242844) and, as a negative control, the non-aphid transmissible isolate N (GeneBank Accession no. D500507) were used. For experiments involving AMV, a field isolate of AMV, confirmed by ELISA and host range, was used. The aphid species Myzus persicae was maintained on broad bean and A. glycines was maintained on virus-free soybean. The protocol for transmission studies of AMV was identical to that used in the SMV study, except only A. glycines was tested. For experiments, plants were periodically observed for symptom development and tested by ELISA 4 to 5 weeks after inoculation access. No transmission of SMV-N occurred in any tests, which together involved 180 aphids each of M. persicae or A. glycines. For the Al5 isolate, transmission efficiencies of 30, 50, and 50% were obtained with 3, 5, and 10 individuals, respectively, of M. persicae per plant. Efficiencies for A. glycines were 30, 40, and 40%. Transmission levels by the two aphid species did not differ significantly (t-test, P = 0.01). For AMV, corresponding transmission efficiencies were 0, 0, and 20%. The data suggest that the introduced A. glycines can be an efficient vector of SMV, but a less efficient vector of AMV, in the North Central region. Transmission of AMV by M. persicae has been documented (1) but was not examined in this study. Transmission of SMV and AMV by A. glycines is of concern because it may increase SMV and AMV incidence. With the recent outbreak of Bean pod mottle virus (BPMV) in the region, the potential for synergism of SMV and BPMV is increased (2). References: (1) M. B. Castillo and G. G. Orlob. Phytopathology 56:1028, 1966. (2) G. L. Hartman et al., eds. 1999. Compendium of Soybean Diseases, 4th Ed. American Phytopathological Society, St. Paul, MN. (3) B. S. Lucas and J. H. Hill. Phytopathol. Z. 99:47, 1980. (4) C. L. Wang et al. Plant Prot. 20:12, 1994.

RevDate: 2019-03-02

Grady MJ, Harper EE, Carlisle KM, et al (2019)

Assessing public support for restrictions on transport of invasive wild pigs (Sus scrofa) in the United States.

Journal of environmental management, 237:488-494 pii:S0301-4797(19)30267-1 [Epub ahead of print].

Wild pigs (Sus scrofa) are a non-native invasive species in the United States that cause significant economic loss, transmit disease, and inflict damage upon natural resources, agriculture, livestock, and property. Geographic distribution of wild pigs in the United States has nearly tripled since 1982, with anthropogenic influences playing a significant role in the expansion. In this regard, there is speculation that a driver of the expansion may be human-mediated movement of wild pigs to new areas for the purpose of sport hunting. In response, states have implemented a variety of wild pig control policies, including legal restrictions on their transport. The success of such policies depends, in part, on their level of public support, which in turn may be influenced by individuals' attitudes concerning wild pigs, their interest in maintaining wild pig populations (e.g., for sport hunting), and their knowledge and awareness of the threats wild pigs pose. Multiple regression was used to analyze data collected from a nationwide survey concerning attitudes toward wild pigs and policies that restrict their transport. Results indicate that a majority of individuals in the United States have negative attitudes toward wild pigs and support policies that restrict their transport and penalize transgressors. Consistent with other invasive species research, findings suggest that as knowledge and awareness of wild pigs increase, so too does support for policies restricting and penalizing transport of wild pigs. Contrary to previous studies, this research also finds that hunters are more likely to support restrictions on wild pig transport than are non-hunters. Overall, these findings suggest that legal restrictions on the transport of wild pigs, even in states with large hunter populations, enjoy broad public support and may help to curb the expansion of wild pig populations.

RevDate: 2019-03-02

Valan M, Makonyi K, Maki A, et al (2019)

Automated Taxonomic Identification of Insects with Expert-Level Accuracy Using Effective Feature Transfer from Convolutional Networks.

Systematic biology pii:5368535 [Epub ahead of print].

Rapid and reliable identification of insects is important in many contexts, from the detection of disease vectors and invasive species to the sorting of material from biodiversity inventories. Because of the shortage of adequate expertise, there has long been an interest in developing automated systems for this task. Previous attempts have been based on laborious and complex handcrafted extraction of image features, but in recent years it has been shown that sophisticated convolutional neural networks (CNNs) can learn to extract relevant features automatically, without human intervention. Unfortunately, reaching expert-level accuracy in CNN identifications requires substantial computational power and huge training datasets, which are often not available for taxonomic tasks. This can be addressed using feature transfer: a CNN that has been pretrained on a generic image classification task is exposed to the taxonomic images of interest, and information about its perception of those images is used in training a simpler, dedicated identification system. Here, we develop an effective method of CNN feature transfer, which achieves expert-level accuracy in taxonomic identification of insects with training sets of 100 images or less per category, depending on the nature of dataset. Specifically, we extract rich representations of intermediate to high-level image features from the CNN architecture VGG16 pretrained on the ImageNet dataset. This information is submitted to a linear support vector machine classifier, which is trained on the target problem. We tested the performance of our approach on two types of challenging taxonomic tasks: (1) identifying insects to higher groups when they are likely to belong to subgroups that have not been seen previously; and (2) identifying visually similar species that are difficult to separate even for experts. For the first task, our approach reached > 92 % accuracy on one dataset (884 face images of 11 families of Diptera, all specimens representing unique species), and > 96 % accuracy on another (2936 dorsal habitus images of 14 families of Coleoptera, over 90 % of specimens belonging to unique species). For the second task, our approach outperformed a leading taxonomic expert on one dataset (339 images of three species of the Coleoptera genus Oxythyrea; 97 % accuracy), and both humans and traditional automated identification systems on another dataset (3845 images of nine species of Plecoptera larvae; 98.6 % accuracy). Reanalyzing several biological image identification tasks studied in the recent literature, we show that our approach is broadly applicable and provides significant improvements over previous methods, whether based on dedicated CNNs, CNN feature transfer, or more traditional techniques. Thus, our method, which is easy to apply, can be highly successful in developing automated taxonomic identification systems even when training datasets are small and computational budgets limited. We conclude by briefly discussing some promising CNN-based research directions in morphological systematics opened up by the success of these techniques in providing accurate diagnostic tools.

RevDate: 2019-03-02

Evangelista C, Olden JD, Lecerf A, et al (2019)

Scale-dependent patterns of intraspecific trait variations in two globally invasive species.

Oecologia pii:10.1007/s00442-019-04374-4 [Epub ahead of print].

Animal species often show substantial intraspecific trait variability (ITV), yet evidence for its flexibility across multiple ecological scales remains poorly explored. Gaining this knowledge is essential to better understand the different processes maintaining ITV in nature. Due to their broad geographic ranges, widespread invasive species are expected to display strong phenotypic variations across their distribution. Here, we quantified the scale-dependent patterns of morphological variability among invasive populations of two global freshwater invaders-red swamp crayfish Procambarus clarkii and pumpkinseed sunfish Lepomis gibbosus-both established in American and European lakes. We quantified patterns in body morphology across different ecological (Individual and Population) and spatial scales (Region). We then analyzed the scale-dependency of morphological variations among lake populations that span a diversity of abiotic and biotic conditions. Next, we used stable isotope analyses to test the existence of ecomorphological patterns linking morphology and trophic niche of individuals. We found that trait variations mainly accounted for at the regional and individual levels. We showed that populations of both species strongly differed between United States and Europe whereas habitat characteristics had a relatively minor influence on morphological variations. Stable isotope analyses also revealed that ecomorphological pattern for the trophic position of L. gibbosus was region-dependent, whereas no ecomorphological patterns were observed for P. clarkii. Overall, our study strongly supports the notion that the patterns of phenotypic variability among invasive populations are likely to modulate the ecological impacts of invasive species on recipient ecosystems.

RevDate: 2019-03-01

Gibson SD, Liczner AR, SR Colla (2019)

Conservation Conundrum: At-risk Bumble Bees (Bombus spp.) Show Preference for Invasive Tufted Vetch (Vicia cracca) While Foraging in Protected Areas.

Journal of insect science (Online), 19(2):.

In recent decades, some bumble bee species have declined, including in North America. Declines have been reported in species of bumble bees historically present in Ontario, including: yellow bumble bee (Bombus fervidus) (Fabricus, 1798), American bumble bee (Bombus pensylvanicus) (DeGeer, 1773), and yellow-banded bumble bee (Bombus terricola) (Kirby, 1837). Threats contributing to bumble bee population declines include: land-use changes, habitat loss, climate change, pathogen spillover, and pesticide use. A response to the need for action on pollinator preservation in North America has been to encourage 'bee-friendly' plantings. Previous studies show differences in common and at-risk bumble bee foraging; however, similar data are unavailable for Ontario. Our research question is whether there is a difference in co-occurring at-risk and common bumble bee (Bombus spp.) floral use (including nectar and pollen collection) in protected areas in southern Ontario. We hypothesize that common and at-risk species forage differently, predicting that at-risk species forage on a limited selection of host plants. We conducted a field survey of sites in southern Ontario, using observational methods to determine bumble bee foraging by species. The results of a redundancy analysis show a difference in foraging between common and at-risk bumblebee species. At-risk bumble bee species show a preference for foraging on invasive, naturalized Vicia cracca (tufted vetch). This finding raises the question of how to preserve or provide forage for at-risk bumble bees, when they show an association with an invasive species often subject to control in protected areas.

RevDate: 2019-03-01

Bytheway JP, PB Banks (2019)

Overcoming prey naiveté: free-living marsupials develop recognition and effective behavioral responses to alien predators in Australia.

Global change biology [Epub ahead of print].

Naiveté in prey arises from novel ecological mismatches in cue recognition systems and antipredator responses following the arrival of alien predators. The multi-level naiveté framework suggests that animals can progress through levels of naiveté towards predator awareness. Alternatively, native prey may be pre-adapted to recognize novel predators via common constituents in predator odors or familiar predator archetypes. We tested predictions of these competing hypotheses on the mechanisms driving behavioral responses of native species to alien predators by measuring responses of native free-living northern brown bandicoots (Isoodon macrourus) to alien red fox (Vulpes vulpes) odor. We compared multiple bandicoot populations either sympatric or allopatric with foxes. Bandicoots sympatric with foxes showed recognition and appropriate anti-predator behavior towards fox odor via avoidance. On the few occasions bandicoots did visit, their vigilance significantly increased, and their foraging decreased. In contrast, bandicoots allopatric with foxes showed no recognition of this predator cue. Our results suggest that vulnerable Australian mammals were likely naïve to foxes when they first arrived, which explains why so many native mammals declined soon after fox arrival. Our results also suggest such naiveté can be overcome within a relatively short time-frame, driven by experience with predators, thus supporting the multi-level naiveté framework. This article is protected by copyright. All rights reserved.

RevDate: 2019-02-28

Marshall D, Work TT, JF Cavey (2003)

Invasion Pathways of Karnal Bunt of Wheat into the United States.

Plant disease, 87(8):999-1003.

Karnal bunt of wheat (caused by Tilletia indica) was first detected in the United States in Arizona in 1996. The seed lots of infected, spring-habit, durum wheat associated with the initial detection were traced to planted fields in California, Arizona, New Mexico, and Texas. However, in the summer of 1997, the disease appeared in unrelated, winter-habit, bread wheat located over 700 km from the nearest potentially contaminated wheat from 1996 (and destroyed prior to reinfection). Here, we examined potential invasion pathways of the fungus associated with the movement of wheat into the United States. We analyzed the USDA/APHIS Port Information Network (PIN) database from 1984 through 2000 to determine likely pathways of introduction based on where, when, and how the disease was intercepted coming into the United States. All interceptions were made on wheat transported from Mexico, with the majority (98.8%) being intercepted at land border crossings. Karnal bunt was not intercepted from any other country over the 17-year period analyzed. Most interceptions were on wheat found in automobiles, trucks, and railway cars. The majority of interceptions were made at Laredo, Brownsville, Eagle Pass, and El Paso, TX, and Nogales, AZ. Karnal bunt was intercepted in all 17 years; however, interceptions peaked in 1986 and 1987. Averaged over all years, more interceptions (19.2%) were made in the month of May than in any other month. Our results indicate that Karnal bunt has probably arrived in the United States on many occasions, at least since 1984. Because of the relatively unaggressive nature of the disease and its reliance on rather exacting weather conditions for infection, we surmised that it is possible this disease has a long period of latent survival between initial arrival and becoming a thriving, established disease.

RevDate: 2019-02-28

Newcombe G, C Nischwitz (2004)

First Report of Powdery Mildew Caused by Erysiphe cichoracearum on Creeping Thistle (Cirsium arvense) in North America.

Plant disease, 88(3):312.

Creeping or Canada thistle (Cirsium arvense (L.) Scop.) is a perennial weed of Eurasian origin that arrived in North America as early as the 1700s (3). Spreading by seeds and rhizomes, it is now widely distributed in Canada, Alaska, and 40 other states. It is apparently absent from Texas, Oklahoma, Louisiana, Mississippi, Alabama, Georgia, Florida, and South Carolina (1). Powdery mildew is common on C. arvense in Europe, but it has never been observed in North America (4). In Europe and Asia, powdery mildew of C. arvense is caused by any one of the following fungi: Leveillula taurica, two species of Sphaerotheca, and varieties of Erysiphe cichoracearum and E. mayorii. Specimens of C. arvense infected with powdery mildew (deposited in the U.S. National Fungus Collections as BPI 843471) were collected in the fall of 2003 near Moscow, ID and in two areas in Oregon (the canyon of the Grande Ronde River and near the base of the Wallowa Mountains). Mycelium and cleistothecia were observed on stems and upper and lower surfaces of leaves. The mean diameter of the cleistothecia was 122 (±11.6) μm. Basally inserted, mycelioid appendages were hyaline or brown and varied considerably in length, but most were in the range of 80 to 120 μm. Asci averaged 58 (±5.5) μm × 35 (±4.1) μm in length and width, respectively. Each ascus bore two ascospores averaging 23 (±1.4) μm × 14 (±1.7) μm. Conidia averaged 30 (±3.0) μm × 14 (±0.8) μm. The specimens fit the description of E. cichoracearum DC. (2). Because the length/breadth ratio of conidia is greater than 2, the specimens could be further diagnosed as E. cichoracearum var. cichoracearum (2). Also noteworthy was the presence of the hyperparasitic Ampelomyces quisqualis Ces. ex Schlechtend. E. cichoracearum is thought to be a cosmopolitan powdery mildew of broad host range, but this concept is difficult to reconcile with the absence of mildew on North American populations of C. arvense for more than 200 years. References: (1) Anonymous. USDA Natural Resources Conservation Service Plants Profile for Cirsium arvense. On-line publication, 2003. (2) U. Braun. A monograph of the Erysiphales (powdery mildews), J. Cramer, Berlin-Stuttgart, 1987. (3) G. Cox. Alien Species in North America and Hawaii, Island Press, Washington, D.C., 1999. (4) D. F. Farr et al. Fungal Databases, Systematic Botany and Mycology Laboratory, ARS, USDA. On-line publication, 2003.

RevDate: 2019-02-28

Gibson LM, Mychajliw AM, Leon Y, et al (2019)

Using the past to contextualize anthropogenic impacts on the present and future distribution of an endemic Caribbean mammal.

Conservation biology : the journal of the Society for Conservation Biology [Epub ahead of print].

Island species are difficult to conserve because they face the synergy of climate change, invasive species, deforestation, and increasing human population densities in areas where land mass is shrinking. The Caribbean island of Hispaniola presents particular challenges because of geopolitical complexities that span 2 countries and hinder coordinated management of species across the island. We employed species distribution modeling to evaluate the impacts of climatic change and anthropogenic activities on the distribution of an endemic mammal of conservation concern, the Hispaniolan solenodon (Solenodon paradoxus). We aggregated occurrence points for this poorly known species for the Last Glacial Maximum (LGM) and the present (1975-2016) based on museum collections, online biodiversity databases, and new field surveys. We quantified degree of overlap between periods and scenarios with Schoener's D. Through a conservation paleobiology lens, we found that over time humans played an increasing role in shaping the distribution of S. paradoxus, thus, providing a foundation for developing conservation strategies on appropriate spatiotemporal scales. Human population density was the single most important predictor of S. paradoxus occurrence. Densities >166 people/km2 corresponded to a near-zero probability of occurrence. Models that accounted for climate but not anthropogenic variables falsely identified suitable habitat in Haiti, where on-the-ground surveys confirm habitat is unavailable. Climate-only models also significantly overestimated the potential for habitat connectivity between isolated populations. Our work highlights that alternative fates for S. paradoxus in the Anthropocene exist across the political border between the Dominican Republic and Haiti due to the fundamentally different economic and political realities of each country. Relationships in the fossil record confirm that Hispaniola's sociopolitical boundary is not biologically significant but instead represents one imposed on the island's fauna in the past 500 years by colonial activity. Our approach reveals how a paleontological perspective can contribute to concrete management insights.

RevDate: 2019-02-28

Hirsch H, Castillo ML, Impson FAC, et al (2019)

Ghosts from the past: even comprehensive sampling of the native range may not be enough to unravel the introduction history of invasive species-the case of Acacia dealbata invasions in South Africa.

American journal of botany [Epub ahead of print].

PREMISE OF THE STUDY: Knowledge about the introduction history (source(s), number and size of introduction events) of an invasive species is a crucial prerequisite to understand invasion success and to facilitate effective and sustainable management approaches, especially for effective biological control. We investigated the introduction history of the Australian legume tree Acacia dealbata in South Africa. Results of this study will not only provide critical information for the management of this species in South Africa, but will also broaden our overall knowledge on the invasion ecology of this globally important invasive tree.

METHODS: We used nuclear microsatellite markers to compare the genetic diversity and structure between 42 native Australian and 18 invasive South African populations and to test different and competing introduction scenarios using Approximate Bayesian Computation analyses.

KEY RESULTS: Australian populations were characterized by two distinct genetic clusters, while South African populations lacked any clear genetic structure and showed significantly lower levels of genetic diversity compared to native range populations. South African populations were also genetically divergent from native populations and the most likely introduction scenario indicated an unknown source population.

CONCLUSIONS: Although we cannot definitely prove the cause of the observed genetic novelty/diversification in South African Acacia dealbata populations, it cannot be attributable to insufficient sampling of native populations. Our study highlights the complexity of unravelling the introduction histories of commercially important alien species.

RevDate: 2019-02-28

Král J, Forman M, Kořínková T, et al (2019)

Insights into the karyotype and genome evolution of haplogyne spiders indicate a polyploid origin of lineage with holokinetic chromosomes.

Scientific reports, 9(1):3001 pii:10.1038/s41598-019-39034-3.

Spiders are an ancient and extremely diverse animal order. They show a considerable diversity of genome sizes, karyotypes and sex chromosomes, which makes them promising models to analyse the evolution of these traits. Our study is focused on the evolution of the genome and chromosomes in haplogyne spiders with holokinetic chromosomes. Although holokinetic chromosomes in spiders were discovered a long time ago, information on their distribution and evolution in these arthropods is very limited. Here we show that holokinetic chromosomes are an autapomorphy of the superfamily Dysderoidea. According to our hypothesis, the karyotype of ancestral Dysderoidea comprised three autosome pairs and a single X chromosome. The subsequent evolution has frequently included inverted meiosis of the sex chromosome and an increase of 2n. We demonstrate that caponiids, a sister clade to Dysderoidea, have enormous genomes and high diploid and sex chromosome numbers. This pattern suggests a polyploid event in the ancestors of caponiids. Holokinetic chromosomes could have arisen by subsequent multiple chromosome fusions and a considerable reduction of the genome size. We propose that spider sex chromosomes probably do not pose a major barrier to polyploidy due to specific mechanisms that promote the integration of sex chromosome copies into the genome.

RevDate: 2019-02-28

Quilodrán CS, Nussberger B, Montoya-Burgos JI, et al (2019)

Hybridization and introgression during density-dependent range expansion: European wildcats as a case study.

Evolution; international journal of organic evolution [Epub ahead of print].

Interbreeding between historically allopatric species with incomplete reproductive barriers may result when species expand their range. The genetic consequences of such hybridization depend critically on the dynamics of the range expansion. Hybridization models during range expansion have been developed but assume dispersal to be independent from neighboring population densities. However, organisms may disperse because they are attracted by conspecifics or because they prefer depopulated areas. Here, through spatially explicit simulations, we assess the effect of various density-dependent dispersal modes on the introgression between two species. We find huge introgression from the local species into the invasive one with all dispersal modes investigated, even when the hybridization rate is relatively low. This represents a general expectation for neutral genes even if the dispersal modes differ in colonization times and amount of introgression. Invasive individuals attracted by conspecifics need more time to colonize the whole area and are more introgressed by local genes, while the opposite is found for solitary individuals. We applied our approach to a recent expansion of European wildcats in the Jura Mountains and the hybridization with domestic cats. We show that the simulations explained better the observed level of introgression at nuclear, mtDNA and Y chromosome markers, when using solitary dispersal for wildcats instead of random or gregarious dispersal, in accordance with ecological knowledge. Using density-dependent dispersal models thus increase the predictive power of the approach. This article is protected by copyright. All rights reserved.

RevDate: 2019-02-28

Galloway KA, ME Porter (2019)

Mechanical properties of the venomous spines of Pterois volitans and morphology among lionfish species.

The Journal of experimental biology pii:jeb.197905 [Epub ahead of print].

The red lionfish, Pterois volitans, an invasive species, has 18 venomous spines: 13 dorsal, 3 anal, and one on each pelvic fin. Fish spines can have several purposes such as defense, intimidation, and for anchoring into crevices. Instead of having hollow spines, lionfish have a tri-lobed cross-sectional shape with grooves that deliver the venom, tapering towards the tip. We aim to quantify the impacts of shape (Second moment of area) and tapering on the mechanical properties of the spine. We performed two-point bending at several positions along the spines of P. volitans to determine mechanical properties (Young's modulus, Elastic energy storage, and Flexural stiffness). The short and recurved anal and pelvic spines are stiffer and resist bending more effectively than the long, dorsal spines. In addition, mechanical properties differ along the length of the spines, most likely because they are tapered. We hypothesize that the highly bendable dorsal spines are used for intimidation, making the fish look larger. The stiffer and energy absorbing anal and pelvic spines are smaller and less numerous, but they may be used for protection since they are located near important internal structures such as the swim bladder. Lastly, spine second moment of area varies across the Pterois genus. These data suggest there may be morphological and mechanical trade-offs among defense, protection, and intimidation of lionfish spines. Overall, the red lionfish venomous spine shape and mechanics may offer protection and intimidate potential predators, significantly contributing to their invasion success.

RevDate: 2019-02-28
CmpDate: 2019-02-28

Lillian S, Redak RA, MP Daugherty (2019)

Assessing the Role of Differential Herbivore Performance Among Plant Species in Associational Effects Involving the Invasive Stink Bug Bagrada hilaris (Hemiptera: Pentatomidae).

Environmental entomology, 48(1):114-121.

Co-occurring plant species can influence the extent of damage to each other by altering the activity or abundance of a shared herbivore. One mechanism by which neighboring host plants exacerbate damage to a focal host is if the neighbor amplifies herbivore populations. We studied the performance of a shared herbivore on a native and an invasive plant, to estimate how strongly the presence of the invasive plant increases local herbivore abundance-in a system in which highly asymmetric spillover herbivory may occur. Specifically, we conducted a series of greenhouse experiments that measured reproduction, development, and survival of the invasive stink bug Bagrada hilaris Burmeister on an invasive annual forb, Sahara mustard (Brassica tournefortii), or a native perennial shrub, four-winged saltbush (Atriplex canescens). All measured aspects of stink bug performance revealed consistently greater performance on Br. tournefortii. Indeed, A. canescens appears to be insufficient for Ba. hilaris to complete its development. Nonetheless, preliminary damage assessments found that both plant species were used as feeding hosts, putative feeding lesions were a more reliable indicator of herbivory than was the degree of yellowing, and higher Ba. hilaris abundance was generally associated with greater sublethal damage to A. canescens. Thus, A. canescens appears to be susceptible to Ba. hilaris herbivory, though more research is needed to assess fitness impacts of this novel herbivore. Our results indicate that differential herbivore performance among host plants may be an important contributor to observed patterns of abundance of a shared herbivore and spillover herbivory between plants.

RevDate: 2019-02-28
CmpDate: 2019-02-28

Honek A, Martinkova Z, Roy HE, et al (2019)

Differences in the Phenology of Harmonia axyridis (Coleoptera: Coccinellidae) and Native Coccinellids in Central Europe.

Environmental entomology, 48(1):80-87.

Harmonia axyridis (Pallas), an invasive non-native species in central Europe, can outcompete other aphidophagous species. The distribution and abundance of H. axyridis vary depending on different host plants, and its effects on native coccinellid communities may change accordingly. The distribution and abundance of coccinellids in central Europe (50°N, 14°E) were investigated from 2010 to 2016. Coccinellids were counted at regular intervals on cereals (Avena, Hordeum, and Triticum), herbaceous plants (Matricaria and Urtica) and trees (Acer, Betula, and Tilia). Additionally, the occurrence over time of each species on these plants was assessed and used as an index of persistence. Across all years, the adults and larvae of H. axyridis were the dominant species of coccinellid on trees. However, H. axyridis was less abundant on herbaceous plants and cereals than on trees. Populations of native coccinellids and H. axyridis co-occurred on trees and persisted for the same length of time, while native coccinellids persisted longer than H. axyridis on herbaceous plants and cereals. Compared to 1976-1986, in the 2010s, the abundance of native species decreased on all plants by 50-70%. The presence of H. axyridis could be considered as a factor driving changes in the assemblages of native coccinellids.

RevDate: 2019-02-28
CmpDate: 2019-02-28

Honek A, Dixon AF, Soares AO, et al (2017)

Spatial and temporal changes in the abundance and compostion of ladybird (Coleoptera: Coccinellidae) communities.

Current opinion in insect science, 20:61-67.

Because of their services to agriculture most ladybirds (Coleoptera: Coccinellidae) are intensively studied predators of mainly phytophagous pests. The study of the long-term variation in the composition of their communities was stimulated by recent dramatic changes in the abundance of some species. We review and evaluate possible effects of the main causes cited in the literature. Agricultural and habitat changes (particularly urbanization) affect coccinellid abundance, both negatively and positively. In the temperate zone dominant species occur most frequently associated with abundant prey populations on crops, weeds and planted stands of trees resulting from human activity. Invasive non-native species of coccinellids may endanger native species through intraguild predation or competition for resources, but their supposed serious negative effects on native species can differ considerably. Climatic change may influence coccinellid species in several ways, including indirect effects through lower trophic levels and desynchronisation of the phenologies of host plants, prey and coccinellid populations. In the near future we do not expect climate warming to have important effects on ladybird diversity globally, but local changes in the composition of coccinellid communities and abundance of particular species could occur.

RevDate: 2019-02-27

Makino T, M Kawata (2019)

Invasive invertebrates associated with highly duplicated gene content.

Molecular ecology [Epub ahead of print].

Invasion of alien species has led to serious problems, including the destruction of native ecosystems. In general, invasive species adapt to new environments rapidly, suggesting that they have high genetic diversity that can directly influence environmental adaptability. However, it is not known how genomic architecture causes genetic diversity that leads to invasiveness. Recent studies have showed that the proportion of duplicated genes (PD) in whole animal genomes correlate with environmental variability within a habitat. Here, we show that PD and propagule size significantly explain the differences in species categories (invasive species, noninvasive species, and parasites). PD correlated negatively with the propagule size. The residual values of regression of PD on propagule size revealed that the invasive species had higher PD values and larger propagule size than those of the noninvasive species, whereas the parasites had lower PD values and smaller propagule size than those of others. There were no correlations between the invasive species and other genomic factors including the genome size, number of genes, and certain gene families. Our results suggest that the PD values of a genome might be a potential genomic source causing genetic variations for adaptation to diverse environments. The results also showed that the invasiveness status of a species would be predicted by the residual values of regression of PD on propagule size. Our innovative approach provides a measure to estimate the environmental adaptability of organisms based on genomic data.

RevDate: 2019-02-27

Su T, Thieme J, Lura T, et al (2019)

Susceptibility Profile of Aedes aegypti L. (Diptera: Culicidae) from Montclair, California, to Commonly Used Pesticides, With Note on Resistance to Pyriproxyfen.

Journal of medical entomology pii:5366013 [Epub ahead of print].

The peridomestic anthropophilic Aedes aegypti L. (Diptera: Culicidae) is originated from the wild zoophilic subspecies Aedes aegypti formosus in sub-Saharan Africa, and currently has a broad distribution in human-modified environments of the tropics and subtropics worldwide. In California, breeding populations were initially detected in 2013 in the cities of Fresno, Madera, and San Mateo, and now can be found in 188 cities of 12 counties in the state. Recent genetic studies suggest that this species invaded California on multiple occasions from several regions of the United States and northern Mexico prior to initial detection. As an invasive species and vector for numerous arboviruses, Ae. aegypti is a primary target of surveillance and control in California. In southern California city of Montclair, a population was identified in September 2015, from which a short-term colony was established in an insectary. The susceptibility of this field population to commonly used pesticides with various modes of action, including 15 formulations against larvae and four against adults, was determined, in reference to a susceptible laboratory colony of the same species. No resistance was shown to most pesticides tested. However, tolerance or reduced susceptibility to spinosad, spinetoram, diflubezuron, and fipronil was detected, and modest levels of resistance to pyriproxyfen (resistance ratio = 38.7-fold at IE50 and 81.5-fold at IE90) was observed. Results are discussed based on the field usage and modes of action of the pesticides tested. Strategic selection and application of pesticides against this population of Ae. aegypti in the urban environments should be taken into consideration.

RevDate: 2019-02-27

Denoël M, Drapeau L, Oromi N, et al (2019)

The role of predation risk in metamorphosis versus behavioural avoidance: a sex-specific study in a facultative paedomorphic amphibian.

Oecologia pii:10.1007/s00442-019-04362-8 [Epub ahead of print].

Evolutionary theory predicts the evolution of metamorphosis over paedomorphosis (the retention of larval traits at the adult stage) in response to life in unfavourable habitats and to the benefits of dispersal. Although many organisms are canalised into obligatory complex or simple life cycles, some species of newts and salamanders can express both processes (facultative paedomorphosis). Previous research highlighted the detrimental effect of fish on both metamorphic and paedomorphic phenotypes, but it remains unknown whether predation risk could induce shifts from paedomorphosis to metamorphosis, whether behavioural avoidance could be an alternative strategy to metamorphosis and whether these responses could be sex-biased. Testing these hypotheses is important because metamorphosed paedomorphs are dispersal individuals which could favour the long-term persistence of the process by breeding subsequently in more favourable waters. Therefore, we quantified the spatial behaviour and timing of the metamorphosis of facultative paedomorphic palmate newts Lissotriton helveticus in response to predation risk. We found that fish induced both male and female paedomorphs to hide more often, but behavioural avoidance was not predictive of metamorphosis. Paedomorphs did not metamorphose more in the presence of fish, yet there was an interaction between sex and predation risk in metamorphosis timing. These results improve our understanding of the lower prevalence of paedomorphs in fish environments and of the female-biased sex ratios in natural populations of paedomorphic newts. Integrating sex-dependent payoffs of polyphenisms and dispersal across habitats is therefore essential to understand the evolution of these processes in response to environmental change.

RevDate: 2019-02-27
CmpDate: 2019-02-27

Katoh M, Tatsuta H, K Tsuji (2017)

Rapid evolution of a Batesian mimicry trait in a butterfly responding to arrival of a new model.

Scientific reports, 7(1):6369.

Batesian mimicry, a phenomenon in which harmless organisms resemble harmful or unpalatable species, has been extensively studied in evolutionary biology. Model species may differ from population to population of a single mimetic species, so different predation pressures might have driven micro-evolution towards better mimicry among regions. However, there is scant direct evidence of micro-evolutionary change over time in mimicry traits. Papilio polytes shows female-limited Batesian mimicry. On Okinawa, one mimicry model is Pachliopta aristolochiae, which was not present on the island until 1993. In P. polytes, the size of the hind-wing white spot, a mimetic trait, is maternally heritable. Among specimens collected between 1961 and 2016, the average white spot size was unchanged before the model's arrival but has rapidly increased since then. However, white spot size showed greater variance after the model's establishment than before. This suggests that before 1993, white spot size in this population was not selectively neutral but was an adaptive trait for mimicking an unpalatable native, Byasa alcinous, which looks like P. aristolochiae apart from the latter's hind-wing white spot. Thus, some females switched their model to the new one after its arrival.

RevDate: 2019-02-26

Baek JT, Hong JH, Tayyab M, et al (2019)

Continuous bubble reactor using carbon dioxide and its mixtures for ballast water treatment.

Water research, 154:316-326 pii:S0043-1354(19)30139-3 [Epub ahead of print].

The treatment of ballast water is indispensable for preventing ecological and economic damage from the spread of invasive species. In this study, a continuous gas bubble reactor (CBR) system was developed for the efficient disinfection of microorganisms in ballast water. Ballast water treatment (BWT) in the CBR was experimentally performed to disinfect Artemia salina in seawater by using 1) pure CO2 and 2) mixtures with CO2, N2, and/or SO2 as a simulated flue gas (CO2/N2: 20%/80% and CO2/N2/SO2: 19.2%/77.0%/3.8%). The BWT efficiency was improved with an increase in gas flowrate, residence time, gas pressure, and CO2 concentration in the gas. The toxicity of SO2 in the CO2 mixture significantly improved the mortality of microorganisms. Since good dispersion of bubbles and effective contact between bubbles and liquid were important factors in the BWT, a 100% mortality rate of microorganisms could be achieved by controlling the operating conditions in the vertical-type CBR with a counter-current flow between the gas bubbles and seawater. The CO2 gas distribution, CO2 solubility, and gas bubble size distribution in the CBR were determined using computational fluid dynamics (CFD) and experimentally confirmed using a high-speed camera. Since excess gas can be recovered from a gas-liquid separator before a ballast tank, the CBR system can be operated without using any toxic or explosive gases in an eco-friendly and energy saving manner.

RevDate: 2019-02-26

Bozorov TA, Luo Z, Li X, et al (2019)

Agrilus mali Matsumara (Coleoptera: Buprestidae), a new invasive pest of wild apple in western China: DNA barcoding and life cycle.

Ecology and evolution, 9(3):1160-1172 pii:ECE34804.

Agrilus mali Matsumara (Coleoptera: Buprestidae) is a wood-boring beetle distributed to eastern China that occasionally injures apple species. However, this wood-boring beetle is new to the wild apple forests (Malus sieversii) of the Tianshan Mountains (western China) and has caused extensive tree mortality. The development of a biological control program for these wild apple forests is a high priority that requires exploration of the life cycle, DNA barcoding and taxonomic status of A. mali. In this study, to determine the diversity of invasive beetles, a fragment of the mitochondrial cytochrome oxidase gene was analyzed. Based on the results, beetles from Gongliu and Xinyuan counties of Xinjiang were identical but differed from those in the apple nursery of Gongliu by a single-nucleotide substitution. We summarize the taxonomic status, relationships, and genetic distances of A. mali among other Agrilus species using the Tajima-Nei model in maximum likelihood phylogeny. Analysis revealed that A. mali was closely related to Agrilus mendax and both belong to the Sinuatiagrulus subgenus. The life cycle of A. mali was investigated based on a monthly regular inspection in the wild apple forests of Tianshan. Similar to congeneric species, hosts are injured by larvae of A. mali feeding on phloem tissue, resulting in serpentine galleries constructed between bark and xylem that prevent nutrient transport and leading to tree mortality. Future studies will focus on plant physiological responses to the invasive beetles and include surveys of natural enemies for a potential classical biological control program.

RevDate: 2019-02-26

Crowther LP, Wright DJ, Richardson DS, et al (2019)

Spatial ecology of a range-expanding bumble bee pollinator.

Ecology and evolution, 9(3):986-997 pii:ECE34722.

Molecular methods have greatly increased our understanding of the previously cryptic spatial ecology of bumble bees (Bombus spp.), with knowledge of the spatial ecology of these bees being central to conserving their essential pollination services. Bombus hypnorum, the Tree Bumble Bee, is unusual in that it has recently rapidly expanded its range, having colonized much of the UK mainland since 2001. However, the spatial ecology of B. hypnorum has not previously been investigated. To address this issue, and to investigate whether specific features of the spatial ecology of B. hypnorum are associated with its rapid range expansion, we used 14 microsatellite markers to estimate worker foraging distance, nest density, between-year lineage survival rate and isolation by distance in a representative UK B. hypnorum population. After assigning workers to colonies based on full or half sibship, we estimated the mean colony-specific worker foraging distance as 103.6 m, considerably less than values reported from most other bumble bee populations. Estimated nest density was notably high (2.56 and 0.72 colonies ha-1 in 2014 and 2015, respectively), estimated between-year lineage survival rate was 0.07, and there was no evidence of fine-scale isolation by distance. In addition, genotyping stored sperm dissected from sampled queens confirmed polyandry in this population (mean minimum mating frequency of 1.7 males per queen). Overall, our findings establish critical spatial ecological parameters and the mating system of this unusual bumble bee population and suggest that short worker foraging distances and high nest densities are associated with its rapid range expansion.

RevDate: 2019-02-26

Linnakoski R, KM Forbes (2019)

Pathogens-The Hidden Face of Forest Invasions by Wood-Boring Insect Pests.

Frontiers in plant science, 10:90.

RevDate: 2019-02-26

O'Brien AL, Dafforn KA, Chariton AA, et al (2019)

After decades of stressor research in urban estuarine ecosystems the focus is still on single stressors: A systematic literature review and meta-analysis.

The Science of the total environment pii:S0048-9697(19)30619-9 [Epub ahead of print].

Natural systems are threatened by a variety of anthropogenic stressors and so understanding the interactive threats posed by multiple stressors is essential. In this study we focused on urban stressors that are ubiquitous to urban estuarine systems worldwide: elevated nutrients, toxic chemical contaminants, built infrastructure and non-indigenous species (NIS). We investigated structural (abundance, diversity and species richness) and functional endpoints (productivity, primary production (chlorophyll-a) and metabolism) commonly used to determine responses to these selected stressors. Through a systematic review of global literature, we found 579 studies of our selected stressors; 93% measured responses to a single stressor, with few assessing the effects of multiple stressors (7%). Structural endpoints were commonly used to measure the effects of stressors (49% of the total 579 studies). Whereas, functional endpoints were rarely assessed alone (10%) but rather in combination with structural endpoints (41%). Elevated nutrients followed by NIS were the most studied single stressors (43% and 16% of the 541 single stressor studies), while elevated nutrients and toxic contaminants were overwhelmingly the most common stressor combination (79% of the 38 multiple stressor studies); with NIS and built infrastructure representing major gaps in multi-stressor research. In the meta-analysis, structural endpoints tended to decrease, while functional endpoints increased and/or decreased in response to different types of organisms or groups. We predicted an antagonistic effect of elevated nutrients and toxic contaminants based on the opposing enriching versus toxic effects of this stressor combination. Of note, biodiversity was the only endpoint that revealed such an antagonistic response. Our results highlight the continuing paucity of multiple stressor studies and provide evidence for opposing patterns in the responses to single and interacting stressors depending on the measured endpoint. The latter is of significant consequence to understanding relevant impacts of stressors in coastal monitoring and management.

RevDate: 2019-02-26

Martínez-Laiz G, Ulman A, Ros M, et al (2019)

Is recreational boating a potential vector for non-indigenous peracarid crustaceans in the Mediterranean Sea? A combined biological and social approach.

Marine pollution bulletin, 140:403-415.

Shipping is understood to be a major vector for the introduction and spread of marine non-indigenous species (NIS). However, recreational boating is still unregulated and its influence as vector has not yet been assessed for the Mediterranean Sea, which is the second most popular recreational boating destination worldwide. This is the first large-scale study to examine this by a combined biological (analyzing hull and marina fouling) and social approach (boaters surveys on maintenance habits, travel patterns and awareness), focused on peracarid crustaceans. A surprisingly high number of NIS were found on vessels cruising Mediterranean waters, and species compositions suggest an exchange between marina and vessel assemblages. This means recreational boating presents a risk for NIS spread which should warrant regulation. Results also implied that regionally coordinated management should be supported by effective local-scale-based management in the Mediterranean, which could improve upon with targeted environmental education to solve lack of awareness.

RevDate: 2019-02-25

Mittan CS, KR Zamudio (2019)

Rapid adaptation to cold in the invasive cane toad Rhinella marina.

Conservation physiology, 7(1):coy075 pii:coy075.

Understanding rapid adaptation to novel environments is essential as we face increasing climatic change. Invasive species are an ideal system for studying adaptation as they are typically introduced to novel environments where they must adapt if they are to persist. We used the invasive cane toad, Rhinella marina, to investigate the contribution of plasticity and evolution to rapid adaptation in a novel environment. Rhinella marina is a neotropical toad that has invaded areas with climates outside of its native environmental niche. The goal of this research was to understand how cane toads persist in northern Florida, the coldest region of their combined natural and invasive range, and originally thought to be beyond their thermal breadth. We measured Critical thermal minima in cane toads from the original, warm introduction location (Miami), and their northern range edge (Tampa) to determine whether northern toads were more cold-tolerant, and to examine the contribution of adaptive plasticity and evolution to any changes in tolerance. Our results show that following acclimation to cold temperatures, southern toads are less tolerant of cold than northern toads. This persistent population difference implies selection for cold-tolerance in northern populations. Differences in individual responses indicate that plasticity is also involved in this response. Our findings have implications for conservation because predatory cane toad invasions threaten local faunas, especially native amphibians. Characterizing specific adaptive mechanisms that allow R. marina to expand its range will identify evolutionary processes that shape a highly successful invasive species.

RevDate: 2019-02-25

Baedke PE, Rucker HR, Mason RT, et al (2019)

Chemical Isolation, Quantification, and Separation of Skin Lipids from Reptiles.

Journal of visualized experiments : JoVE.

Reptiles signal to conspecifics using lipids in their skin, primarily to enable mate tracking and assessment. The isolation of these lipids has utility in research focused on evolutionary patterns and mechanisms of chemical communication, in addition to understanding the waterproofing role of lipids in the evolution of terrestrial life. In an applied approach, such skin-based cues have potential use for wildlife managers dealing with invasive species. The main steps for quantifying reptile skin lipids in the protocol presented here include extraction, total lipid determination, and fractionation via column chromatography, the latter process resulting in purified eluates of compounds which can then either be analyzed to assign compound identifications (e.g., gas chromatography-mass spectrometry [GC-MS]) and/or used directly in more refined bioassays. Skin lipids can be extracted from living skin, shed skin, or dead whole animals, using nonpolar organic solvents (e.g., hexane, benzene, toluene). Extraction solubilizes the lipids and, then, the solvent can be evaporated to yield a measurable lipid-only extract. Fractionation involves the separation of the total lipid extract into specific eluates via traditional column chromatography. The total lipid extract is first bound to a substrate-based column (e.g., alumina) and, then, individual eluates ("fractions") of solvent at specific volumes are passed sequentially through the column to elute sets of compounds from the lipid mixture based on common polarity. The fractions progress in polarity at a standardized sequence by increasing the relative amount of polar solvent (e.g., diethyl ether) in nonpolar solvent. In this manuscript, we describe several methods for extracting skin lipids of reptiles and, then, provide a standard protocol for isolating different sets of compounds based on polarity, using traditional column chromatography. Whole lipid extracts or specific fractions can, then, be used in bioassays to determine any biological activity elicited by the compounds therein.

RevDate: 2019-02-26
CmpDate: 2019-02-26

Liversage K, Kotta J, Aps R, et al (2019)

Knowledge to decision in dynamic seas: Methods to incorporate non-indigenous species into cumulative impact assessments for maritime spatial planning.

The Science of the total environment, 658:1452-1464.

Incorporating ecosystem changes from non-indigenous species (NIS) is an important task of maritime spatial planning. Maritime spatial planning requires a framework that emphasises ecological functioning in a state of dynamic change, including changes to ecosystem services from functions introduced by new NIS. Adaptable modelling toolsets should be developed that can readily incorporate knowledge of new NIS. In the Baltic Sea, recent NIS examples are the North American mud crab Rhithropanopeus harrisii and the Ponto-Caspian round goby Neogobius melanostomus. We performed environmental niche modelling that predicted N. melanostomus will spread across large areas of the Baltic Sea coast while R. harrisii will be limited to regions with high temperature and low salinity conditions. We then performed a meta-analysis on literature showing effects in the Baltic Sea from these NIS and calculated the standardised effect-sizes on relevant ecosystem services. Half the impacts identified for N. melanostomus were considered to increase ecosystem service outcomes, while all R. harrisii impacts caused apparent decreases. Effect coefficients were incorporated into an online impact assessment tool developed by the Estonian Marine Institute. Users with or without science training can use the portal to estimate areas impacted and changes to natural assets (km2) caused by these NIS and cumulative effects from other pressure-types. Impact estimates are based on best available knowledge from manipulative and correlative experiments and thus form a link between science and management. Dynamic modelling techniques informed from varied ecological and methodological perspectives will effectively advise spatial planners about rapid maritime changes and mitigation actions to reduce NIS impacts especially in the focus areas.

RevDate: 2019-02-26
CmpDate: 2019-02-26

Mathai PP, Dunn HM, Magnone P, et al (2019)

Association between submerged aquatic vegetation and elevated levels of Escherichia coli and potential bacterial pathogens in freshwater lakes.

The Science of the total environment, 657:319-324.

Fecal indicator bacteria such as Escherichia coli have been reported to persist and potentially grow in a wide variety of secondary habitats, such as water, beach sand, sediment, periphyton and some algae. However, little is known about their association with submerged macrophytes and how this may influence water quality. In this study, we examined the association of E. coli and potential bacterial pathogens with Eurasian watermilfoil (EWM), an invasive, submerged, macrophyte that has spread across thousands of lakes in North America. EWM samples were collected from 10 lakes in Minnesota, once a month, for six consecutive months from early summer to late fall. Microbiota associated with EWM were examined using membrane filtration, quantitative PCR targeting various bacterial pathogens and host-associated marker genes, and high-throughput DNA sequencing. E. coli densities were generally elevated on EWM samples, and peaked during warmer months. Moreover, our results showed that EWM could serve as a temporal source for transmission of microbiota to the water column. Several potential pathogenic groups, including Aeromonas, Enterobacteriaceae, and Clostridium were present in significantly greater relative abundance on EWM than in water, and waterfowl was predicted to be the major source of fecal contamination. These findings have water quality implications with respect to the potential for submerged macrophytes to harbor and disperse E. coli and other bacterial pathogens in a large number of waterbodies.

RevDate: 2019-02-26
CmpDate: 2019-02-26

Zhang G, Bai J, Jia J, et al (2019)

Shifts of soil microbial community composition along a short-term invasion chronosequence of Spartina alterniflora in a Chinese estuary.

The Science of the total environment, 657:222-233.

Exotic plant invasion can alter native soil microbial community composition, and further influence the biogeochemical processes. Little information is available about the impacts of the invasion chronosequence of Spartina alterniflora on the dynamics of soil microbial community. Soil microbial community in coastal salt marshes invaded by S. alterniflora and reference wetlands covered by Suaeda salsa were investigated using phospholipid fatty acids (PLFAs) profiling along a short-term chronosequence (i.e., 2-, 5- and 10-year) of S. alterniflora invasion in the Yellow River Estuary. Results exhibited an increase in soil moisture, soil organic matter (SOM), soil dissolved organic carbon (DOC), total nitrogen (TN) and the total of PLFAs with increasing invasion ages of S. alterniflora in these coastal salt marshes. Comparatively, soil pH and bulk density exhibited a weak decline along the invasion chronosequence. The elevated values of relative abundance of fungi and the ratios of fungi: bacteria (F/B) in all invaded salt marshes were mainly associated with the accumulation of soil available substrate (e.g., SOM, DOC and TN). S. alterniflora invasion also increased the ratios of gram-positive/gram-negative (G+/G-) bacterial PLFAs, with the highest value occurring in the 2-year invaded salt marshes. The bacterial stress indicated by ratios of cy17:0/16:1ω7c and cy19:0/18:1ω7c consistently decreased along the invasion chronosequence. In conclusion, the shifts of soil microbial community composition were tightly associated with soil variables, such as soil pH and soil nutrient supply. Our findings reflect the short-term chronological effects of S. alterniflora invasion on the soil physicochemical characteristics and microbial communities, which contributes to the linkage between the plant invasion and soil development of coastal salt marshes.

RevDate: 2019-02-25

Alvarez Garcia DM, Pérez-Hérazo A, E Amat (2019)

Spatial and Temporal Variation of the Blowflies Community (Diptera: Calliphoridae) From an Urban Area in Northern South America.

Journal of medical entomology, 56(2):464-471.

Blowflies (Diptera: Calliphoridae) are necrophagous flies with ecological, medical, veterinary, and forensic importance. These flies carry pathogens that they spread to animals and humans, and produce myiasis. Furthermore, they are useful tools in forensic science as indicators of postmortem intervals, and in biomedicine they are successfully used in larval therapy. This study aimed to assess the spatiotemporal variation of the blowflies community from the urban area of Sincelejo City, located in the Colombian Caribbean region. Samplings were conducted from May 2012 to April 2013, using Van Someren Rydon-traps baited with bovine meat, fish, and chicken that decomposed for 48 h. Six species were registered, Cochliomyia macellaria (Fabricius, 1775) was the most abundant, followed by Lucilia eximia (Wiedemann, 1819) and Chrysomya albiceps (Wiedemann, 1819), while Chloroprocta idioidea (Robineau-Desvoidy, 1830), Chrysomya megacephala (Fabricius, 1794), and Lucilia cuprina (Wiedemann, 1830) presented the least individuals. The blowflies community did not change significantly throughout the sampling months or between the periods of low or high rainfall, nor was it influenced by weather variables. Although the species composition was the same in all sampled localities, species abundances presented significant differences. The possible causes of this pattern are discussed herein. Sex ratios were female biased for all the recorded species, except C. idioidea. Our findings provide the first assessment of the blowflies community from the urban area of Sincelejo City.

RevDate: 2019-02-25
CmpDate: 2019-02-25

Uemura Y, Yoshimi S, H Hata (2018)

Hybridization between two bitterling fish species in their sympatric range and a river where one species is native and the other is introduced.

PloS one, 13(9):e0203423.

The distributions of two bitterling fish (subfamily: Acheilognathinae), Tanakia lanceolata and T. limbata, overlap in western Japan. Acheilognathinae fish lay their eggs in the gills of freshwater bivalves, and the early juvenile stage develops in the gills. Populations of freshwater bivalves are declining worldwide, which has limited the number of spawning substrate for bitterlings. T. limbata has been artificially introduced to some rivers in Ehime, Japan, where it coexists with native T. lanceolata, and some hybrids have been observed. We collected both species from several sites in western Japan, and from the Kunichi River system in Ehime, and analyzed genetic population structure based on six microsatellite loci and sequences of the mitochondrial cytochrome b gene. Structure analysis identified three genetically distinct populations: T. lanceolata, T. limbata "West Kyushu", and T. limbata "Setouchi". Two clades of T. limbata were also supported by molecular phylogenetic analyses based on cytochrome b. Hybrids in Ehime originated mostly from interbreeding between male T. lanceolata and female T. limbata "West Kyushu", and made up 10.2% of all collected fish, suggesting that hybrids occurred frequently between females of colonizing species and males of native species. On the other hand, interspecific hybrids were detected at rates of 40.0%, 20.0%, and 17.6% in the Ima River (Fukuoka), Midori River (Kumamoto), and Kase River (Saga), respectively, which are naturally sympatric regions. We found a few T. limbata "Setouchi" in the Midori and Kase Rivers, which were supposed to be introduced from other regions, coexisting with native T. limbata "West Kyushu", and this cryptic invasion may have triggered the interspecific hybridization. These results suggest that artificial introduction of a fish species, a decline in the unionid population, and degradation of habitat have caused broad hybridization of bitterlings in western Japan.

RevDate: 2019-02-26
CmpDate: 2019-02-26

Osório HC, Zé-Zé L, Neto M, et al (2018)

Detection of the Invasive Mosquito Species Aedes (Stegomyia) albopictus (Diptera: Culicidae) in Portugal.

International journal of environmental research and public health, 15(4):.

The Asian tiger mosquito Aedes albopictus is an invasive mosquito originating from the Asia-Pacific region. This species is of major concern to public and veterinary health because of its vector role in the transmission of several pathogens, such as chikungunya, dengue, and Zika viruses. In Portugal, a National Vector Surveillance Network (REde de VIgil&acirc;ncia de VEctores&mdash;REVIVE) is responsible for the surveillance of autochthonous, but also invasive, mosquito species at points of entry, such as airports, ports, storage areas, and specific border regions with Spain. At these locations, networks of mosquito traps are set and maintained under surveillance throughout the year. In September 2017, Ae. albopictus was detected for the first time in a tyre company located in the North of Portugal. Molecular typing was performed, and a preliminary phylogenetic analysis indicated a high similarity with sequences of Ae. albopictus collected in Europe. A prompt surveillance response was locally implemented to determine its dispersal and abundance, and adult mosquitoes were screened for the presence of arboviral RNA. A total of 103 specimens, 52 immatures and 51 adults, were collected. No pathogenic viruses were detected. Despite the obtained results suggest low abundance of the population locally introduced, the risk of dispersal and potential establishment of Ae. albopictus in Portugal has raised concern for autochthonous mosquito-borne disease outbreaks.

RevDate: 2019-02-21

Oliver RE, Cai X, Wang RC, et al (2008)

Resistance to Tan Spot and Stagonospora nodorum Blotch in Wheat-Alien Species Derivatives.

Plant disease, 92(1):150-157.

Tan spot (caused by Pyrenophora tritici-repentis) and Stagonospora nodorum blotch (SNB) (caused by Stagonospora nodorum) are destructive fungal diseases of wheat (Triticum aestivum) throughout the world. Host plant resistance is thought to be an efficient and economical method of control. The objective of the present study was to identify novel sources of tan spot and SNB resistance in wheat genotypes derived from the crosses between wheat and alien species. Evaluations were conducted at the seedling stage in a growth chamber with 100% relative humidity. For each genotype, three replications were used for each disease. Among the 199 wheat-alien species derivatives evaluated, 65 exhibited resistance to tan spot and 30 showed resistance to SNB similar to BR34, a Brazilian wheat line used as the resistant control. Eleven derivatives were resistant to both diseases. Reactions of the derivatives and their respective wheat parents to tan spot and SNB suggest that resistance genes in the derivatives are derived from alien species. These derivatives can serve as desirable bridges for introgression of resistance genes from alien species to cultivated wheat, and could contribute novel and effective tan spot and SNB resistance to wheat breeding.

RevDate: 2019-02-21

Lis JA, PF Whitehead (2019)

Another alien bug in Europe: the first case of transcontinental introduction of the Asiatic burrower bug Macroscytus subaeneus (Dallas, 1851) (Hemiptera: Heteroptera: Cydnidae) to the U.K. through maritime transport.

Zootaxa, 4555(4):588-594 pii:zootaxa.4555.4.10.

The Oriental burrower bug Macroscytus subaeneus (Dallas, 1851) (Hemiptera: Heteroptera: Cydnidae: Cydninae), presently known only from single localities in Flores (Indonesia), the Philippines and Thailand, is recorded from the United Kingdom (hereafter U.K.). A single female specimen was collected on the semi-rural edge of Bath city by a Starling (Sturnus vulgaris L.) and taken to its nest from which it was retrieved during 2015. The specimen is illustrated and its diagnostic characters are provided. We hypothesize that this specimen could have been imported with a shipping container from Thailand.

RevDate: 2019-02-21

Huber BA (2019)

The pholcid spiders of Sri Lanka (Araneae: Pholcidae).

Zootaxa, 4550(1):1-57 pii:zootaxa.4550.1.1.

As part of the Western Ghats-Sri Lanka biodiversity hotspot, Sri Lanka harbors a rich and diverse fauna, especially in the perhumid southwestern part of the island. However, many invertebrate groups such as spiders continue to be poorly studied. The present paper reviews our knowledge about Pholcidae, a family of spiders that is well represented in Sri Lanka, both by numerous (10) introduced species and by a rich native fauna in five genera (described native Sri Lankan species in parentheses): Belisana Thorell, 1898 (6), Leptopholcus Simon, 1893 (1), Pholcus Walckenaer, 1805 (4), Tissahamia Huber, 2018 (4), and Wanniyala Huber Benjamin, 2005 (9). Fourteen species are newly described: Belisana minneriya sp. n., B. badulla sp. n., B. gowindahela sp. n.; Pholcus metta sp. n., P. puranappui sp. n., P. uva sp. n.; Tissahamia karuna sp. n.; Wanniyala mudita sp. n., W. orientalis sp. n., W. upekkha sp. n., W. ohiya sp. n., W. viharekele sp. n., W. mapalena sp. n., and W. labugama sp. n.. All new species are described from males and females. New Sri Lankan records are given for 16 previously described species. Distribution data suggest that most or all of the 24 native species might be endemic to Sri Lanka, but the Indian pholcid fauna remains almost entirely unknown.

RevDate: 2019-02-21

Briscoe Runquist RD, Lake T, Tiffin P, et al (2019)

Species distribution models throughout the invasion history of Palmer amaranth predict regions at risk of future invasion and reveal challenges with modeling rapidly shifting geographic ranges.

Scientific reports, 9(1):2426 pii:10.1038/s41598-018-38054-9.

Palmer amaranth (Amaranthus palmeri) is an annual plant native to the desert Southwest of the United States and Mexico and has become invasive and caused large economic losses across much of the United States. In order to examine the temporal and spatial dynamics of past invasion, and to predict future invasion, we developed a broad array of species distribution models (SDMs). In particular, we constructed sequential SDMs throughout the invasion history and asked how well those predicted future invasion (1970 to present). We showed that invasion occurred from a restricted set of environments in the native range to a diverse set in the invaded range. Spatial autocorrelation analyses indicated that rapid range expansion was facilitated by stochastic, long-distance dispersal events. Regardless of SDM approach, all SDMs built using datasets from early in the invasion (1970-2010) performed poorly and failed to predict most of the current invaded range. Together, these results suggest that climate is unlikely to have influenced early stages of range expansion. SDMs that incorporated data from the most recent sampling (2011-2017) performed considerably better, predicted high suitability in regions that have recently become invaded, and identified mean annual temperature as a key factor limiting northward range expansion. Under future climates, models predicted both further northward range expansion and significantly increased suitability across large portions of the U.S. Overall, our results indicate significant challenges for SDMs of invasive species far from climate equilibrium. However, our models based on recent data make more robust predictions for northward range expansion of A. palmeri with climate change.

RevDate: 2019-02-21

Escobar-Camacho D, Pierotti MER, Ferenc V, et al (2019)

Variable vision in variable environments: the visual system of an invasive cichlid (Cichla monoculus, Agassiz, 1831) in Lake Gatun, Panama.

The Journal of experimental biology pii:jeb.188300 [Epub ahead of print].

An adaptive visual system is essential for organisms inhabiting new or changing light environments. The Panama Canal exhibits such variable environments due to its anthropogenic origin and current human activities. Within the Panama Canal, Lake Gatun harbours several exotic fish species including the invasive peacock bass (Cichla monoculus, Agassiz, 1831), a predatory Amazonian cichlid. In this research, through spectral measurements and molecular and physiological experiments, we studied the visual system of C. monoculus and its adapative capabilities.Our results suggest that (1) Lake Gatun is a highly variable environment where light transmission changes throughout the canal-waterway, and that (2) C. monoculus has several visual adaptations suited for this red-shifted light enviroment. C. monoculus filters short-wavelengths (∼400 nm) from the environment through their ocular media and they tune their visual sensitivities to the available light through opsin gene expression. More importantly, based on shifts in spectral sensitivities of photoreceptors alone, and on transcriptome analysis, C. monoculus exhibits extreme intraspecific variation in the use of vitamin A1/A2 chromophore in their photoreceptors. Fish living in turbid water had higher proportions of vitamin A2, shifting sensitivities to longer-wavelengths, than fish living in clear waters. Furthermore, we also found variation in retinal transcriptomes where fish from turbid and clear-waters exhibited differentially expressed genes that vary greatly in their function. We suggest this phenotypic plasticity has been key in C. monoculus' invasion.

RevDate: 2019-02-21
CmpDate: 2019-02-21

Rizwan S, Benincasa C, Mehmood K, et al (2019)

Fatty Acids and Phenolic Profiles of Extravirgin Olive Oils from Selected Italian Cultivars Introduced in Southwestern Province of Pakistan.

Journal of oleo science, 68(1):33-43.

Mediterranean olive trees have been cultivated in Pakistan for decades to promote olive cultivation and use of olive oil. The qualitative characteristics of seven mono and one multi-varietal extra virgin olive oils (EVOOs) extracted from Italian cultivars grown in different areas of Balochistan a southwestern province of Pakistan were evaluated. Present study aims to assess the impact of bioclimatological change on biochemical profile of exotic cultivars. The dominating fatty acids found in analyzed EVOOs were oleic (65-72%), linoleic (10.61-18.33%) and palmitic acids (12-16%). The tocopherols α, (β+γ) and δ contents showed a great diversity which ranged from (60-408) mg/kg while, total phenol concentration ranged from (200-370) mg/kg. The analyses of phenolic compounds revealed the presence of phenolic acids, phenolic alcohols, secoiridoids, flavonoids, oleuropein and verbascosides. One-way ANOVA revealed significant differences (p < 0.05) regarding studied parameters. Principal component analysis (PCA) was applied to identify the main components and to classify samples into groups in terms of fatty acids and phenolic profiles. The first group (Frantoio, Moraiolo, Pendolino, Multi-varietal mixture) characterized by high amount of oleic acid and MUFAs/PUFAs ratio. The second group (Maurino and Leccino) correlates with SFAs and third (Ottobrattica, Coratina) with PUFAs. Based on the PCA of phenolic profile the studied cultivars were divided into two main groups. Morialo, Pendolino and Maurino correlated with (phenolic acids, hydroxytyrosol, flavonoids and secoiridoids). Frantoio, Ottobrattica, Coratina, multi-varietal and Leccino were correlated with oleuropein, tyrosol and ligstroside aglycon. The obtained data was compared with those obtained from same cultivars in their original and/or different growing area. Marked differences were observed in the composition of oleic, linoleic, palmitic acids, secoiridoids and total phenolic contents. These differences could be due to change in geographical location and climatical condition of Balochistan. The cultivar Moraiolo has shown best adaptation and preserved its biochemical composition among all studied cultivars.

RevDate: 2019-02-21
CmpDate: 2019-02-21

Xu T, Yasui H, Teale SA, et al (2017)

Identification of a male-produced sex-aggregation pheromone for a highly invasive cerambycid beetle, Aromia bungii.

Scientific reports, 7(1):7330.

The longhorned beetle Aromia bungii (Coleoptera: Cerambycidae) is a major pest of stone fruit trees in the genus Prunus, including cherries, apricots, and peaches. Its native range includes China, Korea, Mongolia, and eastern Russia, but it has recently invaded and become established in several countries in Europe, and Japan, and it has been intercepted in shipments coming into North America and Australia. Here, we report the identification of its male-produced aggregation pheromone as the novel compound (E)-2-cis-6,7-epoxynonenal. In field trials in its native range in China, and in recently invaded areas of Japan, the pheromone attracted both sexes of the beetle. Thus, the pheromone should find immediate use in worldwide quarantine surveillance efforts to detect the beetle in incoming shipments. The pheromone will also be a crucial tool in ongoing efforts to eradicate the beetle from regions of the world that it has already invaded.

RevDate: 2019-02-20

Jones GL, Tomlinson M, Owen R, et al (2019)

Shrub establishment favoured and grass dominance reduced in acid heath grassland systems cleared of invasive Rhododendron ponticum.

Scientific reports, 9(1):2239 pii:10.1038/s41598-019-38573-z.

Rhododendron ponticum L. is a damaging invasive alien species in Britain, favouring the moist, temperate climate, and the acidic soils of upland areas. It outshades other species and is thought to create a soil environment of low pH that may be higher in phytotoxic phenolic compounds. We investigated native vegetation restoration and R. ponticum regeneration post-clearance using heathland sites within Snowdonia National Park, Wales; one site had existing R. ponticum stands and three were restoring post-clearance. Each site also had an adjacent, uninvaded control for comparison. We assessed whether native vegetation restoration was influenced post-invasion by soil chemical properties, including pH and phytotoxic compounds, using Lactuca sativa L. (lettuce) bioassays supported by liquid chromatography-mass spectroscopy (LC-MSn). Cleared sites had higher shrub and bare ground cover, and lower grass and herbaceous species cover relative to adjacent uninvaded control sites; regenerating R. ponticum was also observed on all cleared sites. No phenolic compounds associated with R. ponticum were identified in any soil water leachates, and soil leachates from cleared sites had no inhibitory effect in L. sativa germination assays. We therefore conclude that reportedly phytotoxic compounds do not influence restoration post R. ponticum clearance. Soil pH however was lower beneath R. ponticum and on cleared sites, relative to adjacent uninvaded sites. The lower soil pH post-clearance may have favoured shrub species, which are typically tolerant of acidic soils. The higher shrub cover on cleared sites may have greater ecological value than unaffected grass dominated sites, particularly given the recent decline in such valuable heathland habitats. The presence of regenerating R. ponticum on all cleared sites however highlights the critical importance of monitoring and re-treating sites post initial clearance.

RevDate: 2019-02-20

Helsen K, Hagenblad J, Acharya KP, et al (2019)

No genetic erosion after five generations for Impatiens glandulifera populations across the invaded range in Europe.

BMC genetics, 20(1):20 pii:10.1186/s12863-019-0721-4.

BACKGROUND: The observation that many alien species become invasive despite low genetic diversity has long been considered the 'genetic paradox' in invasion biology. This paradox is often resolved through the temporal buildup genetic diversity through multiple introduction events. These temporal dynamics in genetic diversity are especially important for annual invasive plants that lack a persistent seed bank, for which population persistence is strongly dependent on consecutive seed 're-establishment' in each growing season. Theory predicts that the number of seeds during re-establishment, and the levels of among-population gene flow can strongly affect recolonization dynamics, resulting in either an erosion or build-up of population genetic diversity through time. This study focuses on temporal changes in the population genetic structure of the annual invasive plant Impatiens glandulifera across Europe. We resampled 13 populations in 6 regions along a 1600 km long latitudinal gradient from northern France to central Norway after 5 years, and assessed population genetic diversity with 9 microsatellite markers.

RESULTS: Our study suggests sufficiently high numbers of genetically diverse founders during population re-establishment, which prevent the erosion of local genetic diversity. We furthermore observe that I. glandulifera experiences significant among-population gene flow, gradually resulting in higher genetic diversity and lower overall genetic differentiation through time. Nonetheless, moderate founder effects concerning population genetic composition (allele frequencies) were evident, especially for smaller populations. Despite the initially low genetic diversity, this species seems to be successful at persisting across its invaded range, and will likely continue to build up higher genetic diversity at the local scale.

RevDate: 2019-02-20

Ohnishi J, Katsuzaki H, Tsuda S, et al (2006)

Frankliniella cephalica, a New Vector for Tomato spotted wilt virus.

Plant disease, 90(5):685.

Frankliniella cephalica (Crawford) is an invasive species of thrips found in the islands of Yaeyama in the Okinawa Prefecture, Japan. During the late 1990s to early 2000s, a species of thrips was isolated from wild flowers of Bidens pilosa L. and Ipomoea batatas L. growing close to cultivated fields. They were subsequently identified as F. cephalica using fine morphological characteristics with the help of Steve Nakahara (U.S. Department of Agriculture, Beltsville, MD) and Laurence Mound (CSIRO, Australia). Voucher specimens were deposited in the Laboratory of Insect Resources, Faculty of Agriculture, Tokyo University of Agriculture by Shuji Okajima (2). We investigated the ability of F. cephalica to vector Tomato spotted wilt virus (TSWV) by experimentally determining virus transmission efficiency. Newly hatched larvae as much as 12 h old underwent a viral acquisition-access period (AAP) of 24 h, during which they fed on the leaves of Datura stramonium infected with TSWV-O, a Japanese type isolate. Transmission efficiency of adults 4 days after emergence from molt (14 days after the AAP) was determined by a petunia leaf disk assay (3) in which the adults were individually allowed to feed for successive 24-h inoculation access periods (IAP) on two different leaf disks of Petunia × hybrida cv. Polo Blue. Transmission of the virus by the adults was considered positive if at least one of the leaf disks showed viral necrotic spot. We tested 20 randomly selected leaf disks with clear necrotic spots using a simplified rapid immunofilter paper assay. All selected disks were positive for TWSV. The transmission efficiencies were 24.6% for female (n = 57) and 54.4% for male (n = 125) adults. The efficiency was significantly different between sexes (Fisher's exact probability test, P < 0.001). We also examined changes in the virus infection site at different developmental stages in thrips using immunofluorescence microscopy with a polyclonal antibody to N protein of the virus (4). After a 6-h AAP feeding by first instar larvae, the virus was found initially to infect the epithelial cells and then spread throughout the midgut tissue in the second instar larvae 5 days after acquisition of the virus. In viruliferous adults, the virus was present in the salivary glands and on the basement membrane of the midgut tissue. These data indicate that F. cephalica is a new insect vector for TSWV. F. cephalica is a major insect pest of tropical crops in tropical and subtropical coastal belts (1). The presence of a thrips vector in weed hosts surrounding cultivated fields might increase the chance of crops in this habitat becoming infected with viruses. References: (1) M. Lamberts and J. H. Crane. Page 337 in: Advances in New Crops. J. Janick and J. E. Simon, eds. Timber Press, Portland, OR, 1990. (2) M. Masumoto and S. Okajima. Jpn. J. Appl. Entomol. Zool. 48:225, 2004. (3) T. Sakurai et al. Appl. Entomol. Zool. 39:71, 2004. (4) S. Tsuda et al. Ann. Phytopathol. Soc. Jpn. 60:216, 1994.

RevDate: 2019-02-19

Seebens H (2019)

Invasion Ecology: Expanding Trade and the Dispersal of Alien Species.

Current biology : CB, 29(4):R120-R122.

China's ambitious aspirations to build a modern Silk Road will open new avenues for species to spread into regions outside their native range. A new study identifies 14 hot spots of biological invasions falling along the planned economic corridors.

RevDate: 2019-02-19
CmpDate: 2019-02-18

Zhang S, Zhi T, Xu X, et al (2019)

Monogenean fauna of alien tilapias (Cichlidae) in south China.

Parasite (Paris, France), 26:4.

Tilapias are important aquaculture fishes that have been introduced widely all over the world, often carrying their monogenean parasites with them. An extensive investigation on monogeneans of invasive tilapias was conducted in 19 natural water sources in south China between July 2015 and December 2017. We found nine known species of monogeneans, i.e., Enterogyrus coronatus, E. malmbergi, Cichlidogyrus cirratus, C. halli, C. sclerosus, C. thurstonae, C. tilapiae, Scutogyrus longicornis, Gyrodactylus cichlidarum, and one unknown Gyrodactylus species. In addition to reporting ten new hosts and four new geographical records, we observed new morphological characteristics of these species. Observation on living specimens of Enterogyrus spp. demonstrated that these two species have characteristic opisthaptoral retraction capacities, while the opisthaptor glands were not observed in our specimens of E. coronatus and E. malmbergi. The morphological differences of the accessory piece of the male copulatory complex between C. cirratus and C. mbirizei (character for species differentiation) could result from the observation at different perspectives, which indicates that C. mbirizei is likely a synonym of C. cirratus. A more detailed structure of the sclerotized parts of Cichlidogyrus spp. and S. longicornis were revealed by scanning electron microscopy. As was the case for the monogeneans found on alien tilapias from other geographic regions, the present study confirmed the high potential of these monogeneans to establish populations in new habitats.

RevDate: 2019-02-19
CmpDate: 2019-02-18

Chen D, Ali A, Yong XH, et al (2019)

A multi-species comparison of selective placement patterns of ramets in invasive alien and native clonal plants to light, soil nutrient and water heterogeneity.

The Science of the total environment, 657:1568-1577.

A worth noticing pattern in current invasive biology is the clonal ability of many of the world's worst invasive plants. Selective placement of ramets (i.e. foraging behavior) can intensify ramet performance and allocation, and place more ramets in the more favorable microhabitats, which can maximum utilize resource and share risk in heterogeneous environments. Still little is known about whether invasive alien and native clonal plants differ in the selective placement patterns of ramets in invasive clonal plants or not. We used five congeneric pairs of naturally co-occurring invasive alien and native clonal plant species in China. In a glasshouse, we grew all species in pots under a homogeneous and three heterogeneous conditions (i.e. light, soil nutrients or water) subjected to resource-high or -low patches. All biomass parameters and number of ramets significantly increased in resource-high patches in all three types of heterogeneous environments. Interestingly, growth of invasive alien plants benefited significantly more from resource-high patches than native plants in all heterogeneous environments. Overall, invasive had higher biomass parameters per ramet than natives. Ramet parameters of invasive plants also benefited more from resource-low patches than natives. Three different selective placement patterns of ramets in resource-low patches were exhibited in invasive plants: ramet increasing shoot investment (above pattern), increasing root investment (below pattern) and increasing both investments (complete pattern) in the light, soil water and nutrient heterogeneity, respectively. Investment on less, larger ramet was the adaptive strategy of invasive plants in resource-poor patches. The results suggest that adaptively selective placement patterns of ramets promote a higher morphology plasticity and performance in invasive clonal plants over natives. When alien clonal plants spread new areas with light, soil nutrients or water heterogeneity, selective placement patterns of ramets might play an important role in plant performance and competitive superior by capitalizing more on additional resources.

RevDate: 2019-02-18

Morim T, Bigg GR, Madeira PM, et al (2019)

Invasion genetics of the mummichog (Fundulus heteroclitus): recent anthropogenic introduction in Iberia.

PeerJ, 7:e6155 pii:6155.

Human activities such as trade and transport have increased considerably in the last decades, greatly facilitating the introduction and spread of non-native species at a global level. In the Iberian Peninsula, Fundulus heteroclitus, a small euryhaline coastal fish with short dispersal, was found for the first time in the mid-1970s. Since then, F. heteroclitus has undergone range expansions, colonizing the southern region of Portugal, southwestern coast of Spain and the Ebro Delta in the Mediterranean Sea. Cytochrome b sequences were used to elucidate the species invasion pathway in Iberia. Three Iberian locations (Faro, Cádiz and Ebro Delta) and 13 other locations along the native range of F. heteroclitus in North America were sampled. Results revealed a single haplotype, common to all invasive populations, which can be traced to the northern region of the species' native range. We posit that the origin of the founder individuals is between New York and Nova Scotia. Additionally, the lack of genetic structure within Iberia is consistent with a recent invasion scenario and a strong founder effect. We suggest the most probable introduction vector is associated with the aquarium trade. We further discuss the hypothesis of a second human-mediated introduction responsible for the establishment of individuals in the Ebro Delta supported by the absence of adequate muddy habitats linking Cádiz and the Ebro Delta. Although the species has a high tolerance to salinity and temperature, ecological niche modelling indicates that benthic habitat constraints prevent along-shore colonisation suggesting that such expansions would need to be aided by human release.

RevDate: 2019-02-17

Zhang KM, Shen Y, Yang J, et al (2019)

The defense system for Bidens pilosa root exudate treatments in Pteris multifida gametophyte.

Ecotoxicology and environmental safety, 173:203-213 pii:S0147-6513(19)30123-X [Epub ahead of print].

According to the novel weapons hypothesis, root exudates are the inhibition factors for native species growth and development through invasive plants. It is hypothesized that antioxidant system (AOS) presents an effective role in plant defense system. The allelopathy indexes of P. multifida gametophyte biomass and sporogonium conversions rates turn negative with the dose and time effects, and the synthetical allelopathic effect index was -55.07% at 100% treatments under root exudates treatments. Under transmission electron microscopy, the cell structures turn burry. Next, AOS and programmed cell death (PCD) were tested in this study. In AOS, strong activities of superoxide dismutase, catalase, glutathione reductase and glutathione S-transferase (GST) were identified in gametophyte cells under the treatments, as well as the contents of glutathione, ascorbic acid and reduced ascorbate, while GPX activity decreased. Based on the input (SOD activity) and the output (GST activity) of antioxidant system, and the decreasing system control would be a reason leading gametophyte death under root exudates. At day 10, PCD would get its peak of 46.93% at 100% root exudates. We found a dynamic balance of PCD and AOS under the exudates treatments. We detected hexadecanoic acid, ethylene glycol and undecane are three major chemicals in root exudates. Our results provide a reference of AOS and PCD working under root exudates treatments in plants and offer novel strategy for the native species protection and invasion plants control in environment science.

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In the early 1990's, Robert Robbins was a faculty member at Johns Hopkins, where he directed the informatics core of GDB — the human gene-mapping database of the international human genome project. To share papers with colleagues around the world, he set up a small paper-sharing section on his personal web page. This small project evolved into The Electronic Scholarly Publishing Project.

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This is a must read book for anyone with an interest in invasion biology. The full title of the book lays out the author's premise — The New Wild: Why Invasive Species Will Be Nature's Salvation. Not only is species movement not bad for ecosystems, it is the way that ecosystems respond to perturbation — it is the way ecosystems heal. Even if you are one of those who is absolutely convinced that invasive species are actually "a blight, pollution, an epidemic, or a cancer on nature", you should read this book to clarify your own thinking. True scientific understanding never comes from just interacting with those with whom you already agree. R. Robbins

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Papers in Classical Genetics

The ESP began as an effort to share a handful of key papers from the early days of classical genetics. Now the collection has grown to include hundreds of papers, in full-text format.

Digital Books

Along with papers on classical genetics, ESP offers a collection of full-text digital books, including many works by Darwin (and even a collection of poetry — Chicago Poems by Carl Sandburg).

Timelines

ESP now offers a much improved and expanded collection of timelines, designed to give the user choice over subject matter and dates.

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Biographical information about many key scientists.

Selected Bibliographies

Bibliographies on several topics of potential interest to the ESP community are now being automatically maintained and generated on the ESP site.

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