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Bibliography on: Invasive Species

The Electronic Scholarly Publishing Project: Providing world-wide, free access to classic scientific papers and other scholarly materials, since 1993.


ESP: PubMed Auto Bibliography 09 Apr 2020 at 01:44 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: 2020-04-08

Hinman ED, JD Fridley (2020)

Impacts of experimental defoliation on native and invasive saplings: are native species more resilient to canopy disturbance?.

Tree physiology pii:5817963 [Epub ahead of print].

Many non-native, invasive woody species in mesic forests of North America are both shade tolerant and more productive than their native counterparts, but their ability to tolerate disturbances remains unclear. In particular, complete defoliation associated with herbivory and extreme weather events may have larger impacts on invaders if natives maintain greater resource reserves to support regrowth. On the other hand, invaders may be more resilient to partial defoliation by means of upregulation of photosynthesis or may be better able to take advantage of canopy gaps to support refoliation. Across a light gradient, we measured radial growth, new leaf production, non-structural carbohydrates (NSCs), chlorophyll content, and survival in response to varying levels of defoliation in saplings of two native and two invasive species that commonly co-occur in deciduous forests of Eastern North America. Individuals were subjected to one of four leaf removal treatments: no defoliation controls, 50% defoliation over three growing seasons, 100% defoliation over one growing season, and 100% defoliation over two growing seasons. Contrary to our hypothesis, native and invasive species generally did not differ in defoliation responses, although invasive species experienced more pronounced decreases in leaf chlorophyll following full defoliation and native species' survival was more dependent on light availability. Radial growth progressively decreased with increasing defoliation intensity, and refoliation mass was largely a function of sapling size. Survival rates for half-defoliated saplings did not differ from controls (90% of saplings survived), but survival in fully defoliated individuals over one and two growing seasons was reduced to 45% and 15%, respectively. Surviving defoliated saplings generally maintained control NSC concentrations. Under high light, chlorophyll concentrations were higher in half-defoliated saplings compared to controls, which may suggest photosynthetic upregulation. Our results indicate that native and invasive species respond similarly to defoliation, despite the generally faster growth strategy of invaders.

RevDate: 2020-04-08

Groszmann M, Chandler PM, Ross JJ, et al (2020)

Manipulating Gibberellin Control Over Growth and Fertility as a Possible Target for Managing Wild Radish Weed Populations in Cropping Systems.

Frontiers in plant science, 11:190.

Wild radish is a major weed of Australian cereal crops. A rapid establishment, fast growth, and abundant seed production are fundamental to its success as an invasive species. Wild radish has developed resistance to a number of commonly used herbicides increasing the problem. New innovative approaches are needed to control wild radish populations. Here we explore the possibility of pursuing gibberellin (GA) biosynthesis as a novel molecular target for controlling wild radish, and in doing so contribute new insights into GA biology. By characterizing ga 3-oxidase (ga3ox) mutants in Arabidopsis, a close taxonomic relative to wild radish, we showed that even mild GA deficiencies cause considerable reductions in growth and fecundity. This includes an explicit requirement for GA biosynthesis in successful female fertility. Similar defects were reproducible in wild radish via chemical inhibition of GA biosynthesis, confirming GA action as a possible new target for controlling wild radish populations. Two possible targeting approaches are considered; the first would involve developing a species-specific inhibitor that selectively inhibits GA production in wild radish over cereal crops. The second, involves making crop species insensitive to GA repression, allowing the use of existing broad spectrum GA inhibitors to control wild radish populations. Toward the first concept, we cloned and characterized two wild radish GA3OX genes, identifying protein differences that appear sufficient for selective inhibition of dicot over monocot GA3OX activity. We developed a novel yeast-based approach to assay GA3OX activity as part of the molecular characterization, which could be useful for future screening of inhibitory compounds. For the second approach, we demonstrated that a subset of GA associated sln1/Rht-1 overgrowth mutants, recently generated in cereals, are insensitive to GA reductions brought on by the general GA biosynthesis inhibitor, paclobutrazol. The location of these mutations within sln1/Rht-1, offers additional insight into the functional domains of these important GA signaling proteins. Our early assessment suggests that targeting the GA pathway could be a viable inclusion into wild radish management programs that warrants further investigation. In drawing this conclusion, we provided new insights into GA regulated reproductive development and molecular characteristics of GA metabolic and signaling proteins.

RevDate: 2020-04-08

Lazzeri L, Senini C, E Mori (2020)

Interspecific Aggressions between Crested Porcupines and Roe Deer.

Animals : an open access journal from MDPI, 10(4): pii:ani10040623.

Despite being common amongst carnivore mammals, behavioral interference between wild herbivore species is poorly documented. Particularly, in temperate areas, where the ungulate guild is composed of a few species, and large-sized rodents are scarce, most cases of interspecific interactions involve at least one alien species. In this work, we report the first data on behavioral interactions between roe deer, Capreolus capreolus, and crested porcupine, Hystrix cristata. Aggressions by crested porcupines toward roe deer were observed in 34 out of 202 observations of both species feeding at the same site. In the other 168 observations, roe deer and porcupines shared the same feeding area, without any interaction. In 58% cases of interaction, porcupines chased and pushed roe deer away from feeding areas, and in several other cases, roe deer were bitten, or injured with quills. Aggressions by porcupines occurred mostly during warm months, when roe deer are mostly solitary and when competition for food between these species is suggested to be the highest, and against single female individuals.

RevDate: 2020-04-07

Zhao D, P Feng (2015)

Temperature increase impacts personality traits in aquatic non-native species: Implications for biological invasion under climate change.

Current zoology, 61(6):966-971.

Climate change, such as elevated temperatures, may facilitate biological invasion. Aquatic animal systems are more vulnerable to biological invasion when the temperature rises. Animal personality also plays an important role in the possibility of successful establishment of invasive species. However, it is still unclear how personality traits of invasive species will respond to global warming. This study focuses on juveniles of red swamp crawfish Procambarus clarkii, an invasive poikilothermic species with wide distribution throughout the world, and explores how slight temperature increases influence three personality traits (activity, boldness and aggressiveness) of P. clarkii. For each personality, individual variation is to be presented in condition of the same temperature. Individual personality values can significantly increase with the subtle rising of water temperature. Significant correlations among activity, boldness and aggressiveness are found at any temperature stage, and such relationships are maintained at a similar level in the face of different temperatures. It is most likely that significant expressions of personality traits may be an ecological compensation strategy to offset increased metabolic costs when faced with small temperature increases. Aggression syndromes are formed due to stable linkages between personality traits, in order to acquire allopatric resources efficiently and establish a new population in this species.

RevDate: 2020-04-08
CmpDate: 2020-04-06

Averett JP, Morris LR, Naylor BJ, et al (2020)

Vegetation change over seven years in the largest protected Pacific Northwest Bunchgrass Prairie remnant.

PloS one, 15(1):e0227337.

Temperate grasslands are one of the most altered ecosystems on Earth. Consequently, conservation of important characteristics of such ecosystems (e.g., biodiversity) is uncertain even within grasslands that have been protected. Invasion by non-native plants is considered a primary threat to intact grasslands. Here, we evaluated native and non-native vegetation composition change over seven years in the largest Pacific Northwest Bunchgrass remnant. We sampled 124 permanent plots across the Zumwalt Prairie Preserve (northeastern Oregon, USA) twice, seven years apart. With data collected from three grassland community types (xeric prairie, mesic prairie, old fields), we asked: (1) how has species composition changed over time; (2) which species showed the greatest changes in abundance; and (3) how did abundance of Ventenata dubia (the most abundant non-native species) relate to patterns of native and non-native plant abundance? Vegetation composition changed in all three plant communities. Ventenata dubia, an annual non-native grass: (1) became the third most dominant species across the study area; (2) was the only non-native that increased in abundance substantially in all three communities; and (3) was negatively related to native perennial forb cover. Relative cover of non-native species decreased in old fields concomitant with increases in native bunchgrass (Festuca idahoensis) and V. dubia cover. Increased cover of native perennial grasses and non-native annual grasses in old fields were associated with loss of bare ground, but not with reductions in non-native perennial grass cover. Native species dominated in the mesic prairie; however, non-native cover (particularly V. dubia) increased (mean cover increased from 3 to 10%) while mean native perennial forb cover decreased (from 30 to 25%) over time. Continued shifts towards non-native annual grass dominance coupled with potentially declining native perennial forbs, may challenge conservation efforts in one of the last large tracts of Pacific Northwest Bunchgrass Prairie.

RevDate: 2020-04-08
CmpDate: 2020-04-06

Wei CY, Wang JK, Shih HC, et al (2020)

Invasive plants facilitated by socioeconomic change harbor vectors of scrub typhus and spotted fever.

PLoS neglected tropical diseases, 14(1):e0007519.

BACKGROUND: Ecological determinants of most emerging vector-borne diseases are understudied, particularly for neglected tropical disease. Moreover, although socioeconomic impacts can have significant downstream effects on human risks to vector-borne diseases via a change in land cover, particularly facilitating the invasion of exotic plants, related studies remains very scarce. Scrub typhus and spotted fever are neglected diseases emerging around the globe and are transmitted by chigger mites and ticks infective of Orientia tsutsugamushi and Rickettsia spp., respectively, with small mammals as the primary hosts of both vectors.

We investigated how invasions of the plant Leucaena leucocephala caused by widespread abandonment of farmlands driven by industrialization affected abundance of chiggers and ticks in Penghu Island, Taiwan. We determined ectoparasite abundance by trapping small mammals in three types of habitats (invasion site, agricultural field, human residential) every two months for a year. Based on ectoparasite burdens, invasion sites harbored more chiggers and ticks than the other two habitats. Furthermore, hosts maintained higher burdens of both vectors in early winter and burdens of chiggers were more stable across seasons in invasion sites, suggesting that sites with invasive plants could be a temporary refuge for both vectors and might help mitigate the negative influence of unfavorable climate. Infective rates of O. tsutsugamushi in chiggers and Rickettsia in ticks were also consistently not lower in invasion sites. Top soil temperature and relative humidity were similar across the three habitats, but invasion sites contained more of the rat Rattus losea, on which chiggers and ticks were more engorged than those from the most commonly trapped species (Suncus murinus shrew), indicating that abundance of the host R. losea instead of microclimate might better determine the abundance of both vectors.

CONCLUSIONS/SIGNIFICANCE: This study highlights an important but largely neglected issue that socioeconomic change can have unexpected consequences for human health induced particularly by invasive plants, which could become a hotspot for emerging infectious diseases but usually are very hard to be eradicated. In the future, a more comprehensive approach that integrates socio-economics, land use, exotic species, and human health should be considered to fully understand potential emergence of vector-borne diseases.

RevDate: 2020-04-08
CmpDate: 2020-04-07

Sáringer-Kenyeres M, Bauer N, Z Kenyeres (2020)

Active dispersion, habitat requirements and human biting behaviour of the invasive mosquito Aedes japonicus japonicus (Theobald, 1901) in Hungary.

Parasitology research, 119(2):403-410.

Aedes japonicus japonicus is endemic in a number of countries in eastern Asia but has been accidently introduced into many regions of the world including Europe. It was first detected in Hungary in 2012. In 2017, robust populations of the species were found at Lake Balaton, one of the most important tourist destinations in Central Europe. Based on the experience gathered in the above localities, habitat requirements, dispersion abilities and human biting behaviour of the species were studied in western Hungary during 2017 and 2018. Our results show that (a) a few years after its detection at the Slovenian-Hungarian border, Ae. j. japonicus is widespread in at least two-thirds of the western half of Hungary; (b) the species spreads quickly in ecological corridors formed by mosaics of rural areas, detached houses, gardens and small forest patches; (c) Ae. j. japonicus occupies artificial containers; (d) expansion of the species into new areas is slowed by extensive closed forest patches.

RevDate: 2020-04-08
CmpDate: 2020-04-06

Shiganova TA, Sommer U, Javidpour J, et al (2019)

Patterns of invasive ctenophore Mnemiopsis leidyi distribution and variability in different recipient environments of the Eurasian seas: A review.

Marine environmental research, 152:104791.

Harmful invader ctenophore Mnemiopsis leidyi's expansions in the Eurasian Seas, its spatio-temporal population dynamics depending on environmental conditions in recipient habitats have been synthesized. M. leidyi found suitable temperature, salinity and productivity conditions in the temperate and subtropical environments of the semi-enclosed seas, in the coastal areas of open basins and in closed water bodies, where it created autonomous populations. M. leidyi changes its phenology depending on seasonal temperature regime in different environments. We assessed ranges of sea surface temperature, sea surface salinity and sea surface chlorophyll values, sufficient for M. leidyi general occurrence and reproduction based on comprehensive long-term datasets, contributed by co-authors. This assessment revealed that there are at least two eco-types (Southern and Northern) in the recipient seas of Eurasia with features specific for their donor areas. The range of thresholds for M. leidyi establishment, occurrence and life cycle in both eco-types depends on variability of environmental parameters in their native habitats.

RevDate: 2020-04-07

Twining JP, Ian Montgomery W, Price L, et al (2020)

Native and invasive squirrels show different behavioural responses to scent of a shared native predator.

Royal Society open science, 7(2):191841 pii:rsos191841.

Invasive species pose a serious threat to native species. In Europe, invasive grey squirrels (Sciurus carolinensis) have replaced native red squirrels (Sciurus vulgaris) in locations across Britain, Ireland and Italy. The European pine marten (Martes martes) can reverse the replacement of red squirrels by grey squirrels, but the underlying mechanism of how pine martens suppress grey squirrels is little understood. Research suggests the reversal process is driven by direct predation, but why the native red squirrel may be less susceptible than the invasive grey squirrel to predation by a commonly shared native predator, is unknown. A behavioural difference may exist with the native sciurid being more effective at avoiding predation by the pine marten with which they have a shared evolutionary history. In mammals, olfactory cues are used by prey species to avoid predators. To test whether anti-predator responses differ between the native red squirrel and the invasive grey squirrel, we exposed both species to scent cues of a shared native predator and quantified the responses of the two squirrel species. Red squirrels responded to pine marten scent by avoiding the feeder, increasing their vigilance and decreasing their feeding activity. By contrast, grey squirrels did not show any anti-predator behaviours in response to the scent of pine marten. Thus, differences in behavioural responses to a shared native predator may assist in explaining differing outcomes of species interactions between native and invasive prey species depending on the presence, abundance and exposure to native predators.

RevDate: 2020-04-07

Hager HA, Ryan GD, JA Newman (2020)

Effects of elevated CO2 on competition between native and invasive grasses.

Oecologia pii:10.1007/s00442-020-04636-6 [Epub ahead of print].

Elevated atmospheric CO2 concentration increases the performance of invasive plants relative to natives when grown in monoculture, but it is unclear how that will affect the relative competitive abilities per se of invasive and native grasses grown together. We tested competitive outcomes for four native and four invasive perennial C3 and C4 grasses under ambient (390 ppm) and elevated (700 or 1000 ppm) CO2 concentrations in the greenhouse with non-limiting water and nutrients. We predicted that elevated CO2 would increase the competitive suppression of native grasses by invasive grasses. To test this, we determined the relative interaction intensity of biomass allocation for natives grown alone vs. those grown in native-invasive species pairs. We also measured photosynthetic traits that contribute to plant invasiveness and may be affected by elevated CO2 concentrations for species pairs in mixture to determine native-invasive relative performance. We found no effect of CO2 for the aboveground biomass and tiller production measures of interaction intensity or for relative performance for most of the measured photosynthetic traits. In competition, the invaders nearly always outperform natives in biomass and tiller production, regardless of CO2 level. The results suggest that increasing CO2 concentration alone has little effect on grass competitive outcomes under controlled conditions.

RevDate: 2020-04-06

Brown TR, Todd CR, Hale R, et al (2020)

Testing the adaptive advantage of a threatened species over an invasive species using a stochastic population model.

Journal of environmental management, 264:110524 pii:S0301-4797(20)30458-8 [Epub ahead of print].

Introduced species are a major threat to freshwater biodiversity. Often eradication is not feasible, and management must focus on reducing impacts on native wildlife. This requires an understanding of how native species are affected but also how environmental characteristics influence population dynamics of both invasive and native species. Such insights can inform how to manipulate systems in order to take advantage of life-history traits native species possesses that invaders do not. The highly invasive fish, Gambusia holbrooki, has been implicated in the decline of many freshwater fish and amphibians. In south-eastern Australia, one of these is the threatened native fish, Galaxiella pusilla. As G. pusilla can survive periods without surface water, this presents an opportunity for adaptive management, given G. holbrooki lack these adaptations. We develop a stochastic population model to explore the impact of G. holbrooki on G. pusilla and test the feasibility of both natural and management-induced drying to protect this species. Our results support recent empirical studies showing G. holbrooki are a serious threat to G. pusilla persistence, especially through impacts on larval survival. While persistence is more likely in water bodies that frequently dry out, even optimal natural drying regimes may be insufficient when impacts from G. holbrooki are high. However, management-induced drying may allow persistence of G. pusilla in sites inhabited by both species. Given our model outcomes, the biology of these species and the habitats they occupy, we recommend maintaining or restoring aquatic and riparian vegetation and natural drying regimes to protect G. pusilla from G. holbrooki, in addition to undertaking management-induced drying of invaded water bodies. Our results provide insights into how the effects of G. holbrooki may be mitigated for other native species, which is important given this species is perhaps the most pervasive invader of freshwater ecosystems. We conclude with a discussion of the potential for using disturbance processes in the management of invasive species more broadly in freshwater and terrestrial systems.

RevDate: 2020-04-06

Kropf B, Schmid E, Schönhart M, et al (2020)

Exploring farmers' behavior toward individual and collective measures of Western Corn Rootworm control - A case study in south-east Austria.

Journal of environmental management, 264:110431 pii:S0301-4797(20)30365-0 [Epub ahead of print].

Invasive species are considered a major threat for global agricultural production, biodiversity and ecosystem services. Their spread and establishment is mainly influenced by bio-physical factors, but also by people's activities such as tourism or farming. Understanding farmers' behavior is necessary to develop effective control measures. We conducted qualitative semi-structured interviews in south-east Austria to explore factors that facilitate or impede farmers' behavior to individually or collectively control the invasive Western Corn Rootworm (WCR, Diabrotica virgifera virgifera). We analyze the interview contents using the Capability-Opportunity-Motivation-Behavior model (COM-B model). Our results show that farmers' motivation and related behavior is influenced by intra- and interpersonal factors such as their knowledge about WCR control measures (capability psychological), perceived societal acceptance of WCR control measures or perceived normative obligations to participate in collective measures (opportunity social). Farmers' motivation (reflective and automatic) for implementing individual or collective WCR control measures is mainly determined by their perceived self-efficacy, their perceived efficacy of WCR control measures and the perceived severity of WCR damages. Contextual factors such as environmental conditions, legal regulations, the landscape composition, the farm type or financial impacts of WCR control measures (opportunity physical) are essential prerequisites for farmers' behavior. The results suggest that new modes of knowledge transfer are required to facilitate the proactive implementation of individual and collective WCR control measures prior to trigger events, such as severe WCR damages. The development of a trusting and communicative environment between farmers is key for collective WCR control. Exchange with residents about WCR and applied control measures may help to create a shared understanding and increase societal acceptance. Moreover, a long-term and proactive coordination which meets individual famers' needs is required to implement collective WCR control measures. Farmers who have successfully implemented individual and collective WCR measures may encourage non-applicants and sceptics by "learning from peers".

RevDate: 2020-04-06

Bermejo R, MacMonagail M, Heesch S, et al (2020)

The arrival of a red invasive seaweed to a nutrient over-enriched estuary increases the spatial extent of macroalgal blooms.

Marine environmental research, 158:104944 pii:S0141-1136(19)30823-2 [Epub ahead of print].

The red seaweed Agarophyton vermiculophyllum is an invasive species native to the north-west Pacific, which has proliferated in temperate estuaries of Europe, North America and Africa. Combining molecular identification tools, historical satellite imagery and one-year seasonal monitoring of biomass and environmental conditions, the presence of A. vermiculophyllum was confirmed, and the invasion was assessed and reconstructed. The analysis of satellite imagery identified the first bloom in 2014 and revealed that A. vermiculophyllum is capable of thriving in areas, where native bloom-forming species cannot, increasing the size of blooms (ca. 10%). The high biomass found during the peak bloom (>2 kg m-2) and the observation of anoxic events indicated deleterious effects. The monitoring of environmental conditions and biomass variability suggests an essential role of light, temperature and phosphorous in bloom development. The introduction of this species could be considered a threat for local biodiversity and ecosystem functioning in a global change context.

RevDate: 2020-04-06

Savva I, Chartosia N, Antoniou C, et al (2020)

They are here to stay: The biology and ecology of lionfish (Pterois miles) in the Mediterranean Sea.

Journal of fish biology [Epub ahead of print].

The lionfish, Pterois miles, is one of the most recent Lessepsian immigrants into the Mediterranean Sea and it poses a serious threat to marine ecosystems in the region. This study assesses the basic biology and ecology of lionfish in the Mediterranean, examining morphometrics, reproduction and diet as well as population structure and distribution. The population density of lionfish increased dramatically in Cyprus since the first sighting in late 2012; by 2018 aggregations of up to 70 lionfish are found on rocky grounds with complex relief and artificial reefs in depths of 0-50 m. Lionfish in Cyprus become mature within a year and adults are spawning capable year-round, with peak spawning in summer when the sea surface temperature reaches 28.4 °C. The Cypriot lionfish grow faster and bigger than in their native range, and females are more common than males. Lionfish are generalist predators in these waters, as also found in their native range, consuming a range of teleost and crustacean prey, some of which are of high economic value (e.g. Spicara smaris and Sparisoma cretense) or have an important role in local trophic webs (e.g. Chromis chromis). Overall, the reproductive patterns, the presence of juveniles and adults throughout the year, the rapid growth rates and the generalist diet indicate that lionfish are thriving and are now already well established in the region and could potentially become the serious nuisance that they are in their temperate and tropical western Atlantic invasive range. This article is protected by copyright. All rights reserved.

RevDate: 2020-04-04

Ferrandez-Villena M, Ferrandez-Garcia CE, Garcia-Ortuño T, et al (2020)

The Influence of Processing and Particle Size on Binderless Particleboards Made from Arundo donax L. Rhizome.

Polymers, 12(3): pii:polym12030696.

The giant reed (Arundo donax L.) is considered one of the world's 100 worst invasive species. The main method by which this species propagates is by growth of scattered fragments of rhizome, spreading without control with very strong, deep roots. Agricultural waste consists of lignocellulosic materials that can substitute natural wood and offer a suitable alternative with which to manufacture boards for furniture, packaging and building purposes. The objectives of this work were to obtain binderless particleboards using giant reed rhizome as the raw material, to evaluate their mechanical and physical properties according to the applicable European standards and to assess the self-binding mechanism of the particles in the board. Six types of boards (12 classes) were manufactured with giant reed rhizome biomass. They were manufactured with a temperature of 110 °C, a pressure of 2.5 MPa and pressing times of 7 and 15 min, applying one or two pressing cycles. The results achieved for modulus of rupture (14.2 N/mm2), modulus of elasticity (2052.45 N/mm2) and internal bonding strength (1.12 N/mm2) show that the mechanical properties were improved by using a smaller rhizome particle size and two pressing cycles.

RevDate: 2020-04-04

Avanesyan A, WO Lamp (2020)

Use of Molecular Gut Content Analysis to Decipher the Range of Food Plants of the Invasive Spotted Lanternfly, Lycorma delicatula.

Insects, 11(4): pii:insects11040215.

Spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), is an introduced highly invasive insect pest in the US that poses a significant risk to forestry and agriculture. Assessing and predicting plant usage of the lanternfly has been challenging, and little is known regarding the lanternfly nymph association with its host plants. In this study, we focused on: (a) providing a protocol for using molecular markers for food plant identification of L. delicatula; (b) determining whether the ingested plant DNA corresponds with DNA of the plants from which the lanternfly was collected; and, (c) investigating the spectrum of ingested plants. We utilized gut contents of third and fourth instar nymphs that were collected from multiple plants; we isolated ingested plant DNA and identified consumed plants. We demonstrated that (a) up to 534 bp of the rbcL gene from ingested plants can be detected in L. delicatula guts, (b) ingested plants in ~93% of the nymphs did not correspond with the plants from which the nymphs were collected, and (c) both introduced and native plants, as well as woody and non-woody plants, were ingested. This information will aid effective the monitoring and management of the lanternfly, as well as predict the lanternfly host plants with range expansion.

RevDate: 2020-04-04

Álvarez X, Cancela Á, Freitas V, et al (2020)

Hydrothermal Carbonization and Pellet Production from Egeria densa and Lemna minor.

Plants (Basel, Switzerland), 9(4): pii:plants9040425.

Biofuels are seen as a potential option for mitigating the effects of fossil fuel use. On the other hand, nutrient pollution is accelerating eutrophication rates in rivers, lakes, and coastal waters. Harvesting aquatic plants to produce biofuels could mitigate this problem, though it is important to attack the problem at source, mainly as regards the contribution of nutrients. For the first time, solid biofuels were obtained in the forms of carbon and pellets from the aquatic plants Egeria densa, which is classed as an invasive plant under the Spanish Catalogue of Exotic Invasive Species, and Lemna minor, both of which can be found in the Umia River in north-west Spain. The essential oils and macro- and microelements present in both these plants were also extracted and analyzed. The higher heating values (HHVs) of the carbon products obtained ranged from 14.28 to 17.25 MJ/kg. The ash content ranged from 22.69% to 49.57%. The maximum yield obtained for biochar for Egeria densa at 200 °C was 66.89%. Temperature significantly affects solid hydrochar yield. The HHVs of the pellets obtained ranged from 11.38 to 13.49 MJ/kg. The use of these species to obtain biofuels through hydrothermal carbonization (HTC) and pellets is a novel and effective approach that will facilitate the removal of nutrients that cause eutrophication in the Umia River. The elements extracted show that harvesting these plants will help to remove excessive nutrients from the ecosystem.

RevDate: 2020-04-04

Lucardi RD, Wallace LE, GN Ervin (2020)

Patterns of Genetic Diversity in Highly Invasive Species: Cogongrass (Imperata cylindrica) Expansion in the Invaded Range of the Southern United States (US).

Plants (Basel, Switzerland), 9(4): pii:plants9040423.

The spatial expansions of invasive organisms in the novel range are generally expected to follow an isolation-by-distance relationship (IBD) if the invasion is biologically driven; however, many invasions are facilitated anthropogenically. This research focused on the extant expansion patterns of cogongrass (Imperata cylindrica). Cogongrass is a widespread invasive species throughout the southern United States (US). Patterns of infestation vary among US states. Cogongrass is pyrogenic, and its invasion threatens softwood (Pinus spp.) plantations, a substantial economic market for this US region. Over 600 individuals were sampled from seven invaded US states, using amplified fragment length polymorphisms (AFLPs) to assess genetic diversity and population structure. We suspected that differences in historical management efforts among US states influenced differences in genetic diversity and structure. We detected two genetic lineages at the highest level of analysis. One genetic lineage was locally restricted, whereas the other was found throughout the study region. Admixed individuals were found in all US states and consistently co-occurred with the dominant lineage, suggesting that secondary contact and hybridization may have facilitated expansion. The widespread prevalence of only one of the two detected genetic lineages suggests a primary genetic lineage responsible for on-going population expansion in the US.

RevDate: 2020-04-03

Wade L, G Roberts (2020)

Linguistic Convergence to Observed Versus Expected Behavior in an Alien-Language Map Task.

Cognitive science, 44(4):e12829.

Individuals shift their language to converge with interlocutors. Recent work has suggested that convergence can target not only observed but also expected linguistic behavior, cued by social information. However, it remains uncertain how expectations and observed behavior interact, particularly when they contradict each other. We investigated this using a cooperative map task experiment, in which pairs of participants communicated online by typing messages to each other in a miniature "alien" language that exhibited variation between alien species. The overall task comprised three phases, in each of which participants were told that they would be paired with a different partner. One member of the pair was given explicit linguistic expectations in each phase, while the software controlled whether or not observed behavior from their partner would be consistent or inconsistent with these expectations. The other participant was given no such expectations, allowing us to control for the role of expectation. Participants converged to both observed and expected linguistic behavior, and convergence was boosted when observation and expectation were aligned. When expected and observed behavior were misaligned, participants updated their expectations, though convergence levels did not drop. Furthermore, participants generalized what they learned about one partner to apparent novel partners of the same alien species. We also discuss individual variation in convergence patterns and the lack of a relationship between linguistic convergence and success at the map task. Findings are consistent with observations outside the laboratory that language users converge toward expected linguistic behavior. They also have broader implications for understanding linguistic accommodation and the influence of social information on linguistic processing and production.

RevDate: 2020-04-02

Capron A, Stewart D, Hrywkiw K, et al (2020)

In Situ Processing and Efficient Environmental Detection (iSPEED) of tree pests and pathogens using point-of-use real-time PCR.

PloS one, 15(4):e0226863 pii:PONE-D-19-33958.

Global trade and climate change are responsible for a surge in foreign invasive species and emerging pests and pathogens across the world. Early detection and surveillance activities are essential to monitor the environment and prevent or mitigate future ecosystem impacts. Molecular diagnostics by DNA testing has become an integral part of this process. However, for environmental applications, there is a need for cost-effective and efficient point-of-use DNA testing to obtain accurate results from remote sites in real-time. This requires the development of simple and fast sample processing and DNA extraction, room-temperature stable reagents and a portable instrument. We developed a point-of-use real-time Polymerase Chain Reaction system using a crude buffer-based DNA extraction protocol and lyophilized, pre-made, reactions for on-site applications. We demonstrate the use of this approach with pathogens and pests covering a broad spectrum of known undesirable forest enemies: the fungi Sphaerulina musiva, Cronartium ribicola and Cronartium comandrae, the oomycete Phytophthora ramorum and the insect Lymantria dispar. We obtained positive DNA identification from a variety of different tissues, including infected leaves, pathogen spores, or insect legs and antenna. The assays were accurate and yielded no false positive nor negative. The shelf-life of the lyophilized reactions was confirmed after one year at room temperature. Finally, successful tests conducted with portable thermocyclers and disposable instruments demonstrate the suitability of the method, named in Situ Processing and Efficient Environmental Detection (iSPEED), for field testing. This kit fits in a backpack and can be carried to remote locations for accurate and rapid detection of pests and pathogens.

RevDate: 2020-04-02

Lucardi RD, Cunard CE, Hughes SC, et al (2020)

An initial industrial flora: A framework for botanical research in cooperation with industry for biodiversity conservation.

PloS one, 15(4):e0230729 pii:PONE-D-19-26627.

Humans have created an accelerating, increasingly connected, globalized economy, resulting in a more globalized, shared flora. The prevention of new, establishing species is less costly, both economically and ecologically, and is more manageable than eradicating nonnative invasive species once they are widespread and negatively impactful. We ask if international trade hubs and points-of-entry with high-volume trade, constant disturbance, and propagule rain have a higher number of nonnative species compared to surrounding areas and if they may serve as initial establishment sites and refugia of nonnative, invasive populations. Therefore, we partnered with various federal, state, and private interests to evaluate the floristic composition at the Garden City Terminal of the Port of Savannah, Georgia, USA. We conducted the following study to demonstrate the collaborative relationship-building between researchers and industry and to develop a framework for biodiversity conservation. In our study, we collected all reproductive vascular plants in the secured areas of the Garden City Terminal during four major seasonal time points over two years. The percent of nonnative species and number of nonnative plant species per hectare at this industrial location exceeded all other comparison floras. The mean coefficient of conservatism was lowest among the comparison floras, indicating a highly disturbed habitat with nonnative, weedy native, and other native species tolerant of disturbance. Our study represents one of the first inventories of an Industrialized Flora and indicates that such areas are hot-spots of nonnative plant diversity and possible sources of emergent plant invasions. We posit that industrial sites and international points-of-entry should be considered laboratories for research on species transport and introduction, adaptability, and taxonomic delineation to better understand the mechanisms and consequences of biotic homogenization due to the volume and frequency of anthropogenic activities.

RevDate: 2020-04-01

Rothenberger M, Armstrong A, Gaugler T, et al (2020)

Bridging information domains to improve ecological understanding of biological invasions in a marine ecosystem.

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

Bioinvasions are widely recognized as a growing threat to marine ecosystems, but our ability to predict future invasions and develop control measures is hampered by a lack of timely and accessible information. Although scientific research and traditional ecological monitoring programs amass information on the spread and impact of introduced species, there are other domains in which valuable information on marine invasive species exist. The problem is that actors within the various domains may be guided by different objectives and investigative approaches, creating barriers to information sharing and effective application. We present a practical method for integrating information on two marine invasive species collected using three different approaches: standardized ecological monitoring, online reporting databases, and surveys of anglers and crabbers. Focusing on two recently introduced species with different characteristics, the Asian shore crab (Hemigrapsus sanguineus) and Chinese mitten crab (Eriocheir sinensis), in the Hudson-Raritan watershed of New York and New Jersey, we used sensitivity analyses to explore the relative contribution of each information source to our knowledge of species abundance and distribution. By demonstrating that data integration can produce an image of the invasion process that would not have emerged had we used any one method individually, our results provide evidence for the advantages of an interdisciplinary approach. For multifaceted problems such as bioinvasions that require swift action without having complete information, researchers and practitioners may need to supplement standard scientific method with other information domains in order to amplify detectability of marine pests at an early stage when populations are still small and manageable. Article Impact Statement: Information sharing across information domains improves understanding of invasion trends. This article is protected by copyright. All rights reserved.

RevDate: 2020-04-01

Cafa G, Baroncelli R, Ellison CA, et al (2020)

Impatiens glandulifera (Himalayan balsam) chloroplast genome sequence as a promising target for populations studies.

PeerJ, 8:e8739 pii:8739.

Background: Himalayan balsam Impatiens glandulifera Royle (Balsaminaceae) is a highly invasive annual species native of the Himalayas. Biocontrol of the plant using the rust fungus Puccinia komarovii var. glanduliferae is currently being implemented, but issues have arisen with matching UK weed genotypes with compatible strains of the pathogen. To support successful biocontrol, a better understanding of the host weed population, including potential sources of introductions, of Himalayan balsam is required.

Methods: In this molecular study, two new complete chloroplast (cp) genomes of I. glandulifera were obtained with low coverage whole genome sequencing (genome skimming). A 125-year-old herbarium specimen (HB92) collected from the native range was sequenced and assembled and compared with a 2-year-old specimen from UK field plants (HB10).

Results: The complete cp genomes were double-stranded molecules of 152,260 bp (HB92) and 152,203 bp (HB10) in length and showed 97 variable sites: 27 intragenic and 70 intergenic. The two genomes were aligned and mapped with two closely related genomes used as references. Genome skimming generates complete organellar genomes with limited technical and financial efforts and produces large datasets compared to multi-locus sequence typing. This study demonstrates the suitability of genome skimming for generating complete cp genomes of historic herbarium material. It also shows that complete cp genomes are solid genetic markers for population studies that could be linked to plant evolution and aid with targeting native range and natural enemy surveys for biocontrol of invasive species.

RevDate: 2020-04-01

Gusakov VA, AA Sylaieva (2019)

Bratislavia dadayi (Michaelsen 1905) (Annelida, Clitellata, Naididae): discovery of an alien oligochaete in a technogenic fresh water body in Ukraine.

Zootaxa, 4711(2):zootaxa.4711.2.7 pii:zootaxa.4711.2.7.

A non-native oligochaete, Bratislavia dadayi (Michaelsen 1905), is recorded from a water body of the cooling system of the Khmelnitsky Nuclear Power Plant (Ukraine). This is the first registration of this species in the central part of the European continent, far from sea and river navigable waterways. The only previous record of B. dadayi in Europe had been from a Belgian estuary. The occurrence in samples taken over several years, and the presence of sexually mature individuals in the Ukrainian population indicate the worm's successful naturalization in the new habitat. In this paper, we analyze the species' morphology and abundance in the Ukrainian population and discuss its ecology, current and potential distribution.

RevDate: 2020-04-01

Wahl DB, N Green (2020)

Stenarella domator (Poda) [Hymenoptera: Ichneumonidae], a newly introduced species to the Nearctic, and a summary of adventive Nearctic species of Ichneumonidae.

Zootaxa, 4743(1):zootaxa.4743.1.8 pii:zootaxa.4743.1.8.

The western Palaearctic ichneumonid Stenarella domator (Poda) is newly recorded for the Nearctic. Photographs and a new key to the genera of Nearctic Osprynchotina (Cryptinae: Cryptini) are provided. Like other species in the Osprynchotina, S. domator is an ectoparasitoid of aculeate Hymenoptera which use mud/earth in their nests. The 25 species of adventive Nearctic ichneumonids are reviewed, and the implications of their biologies for Nearctic host ranges are discussed.

RevDate: 2020-04-01

Scripter MJ, Price WW, RW Heard (2020)

Redescription of Deltamysis holmquistae Bowman amp; Orsi, 1992 (Crustacea: Mysida: Mysidae), a mysid species new to the Atlantic Ocean with observations on the taxonomic status of Kochimysis Panampunnayil amp; Biju, 2007.

Zootaxa, 4729(4):zootaxa.4729.4.3 pii:zootaxa.4729.4.3.

The first occurrences of the estuarine mysid Deltamysis holmquistae Bowman Orsi from the Atlantic Ocean are documented from sites on the eastern Florida and northwest Gulf of Mexico (Texas) coasts of North America. Based on examination of type material and specimens from Florida and Texas, considerable morphological variability and additional characters were observed necessitating a rediagnosis of the monotypic genus Deltamysis and a redescription of D. holmquistae. As a result of these new taxonomic criteria, the Indian Ocean species, Kochimysis pillaii Panampunnayil Biju, described from southwest coastal India, is subsumed as a junior synonym of D. holmquistae. The current distribution of this apparently invasive species is probably due to maritime commerce. The geographical location of the endemic or source populations of D. holmquistae remains undetermined; however, its co-occurrence in California with three introduced Asian mysids suggests a northern Indian Ocean or northwest Pacific origin.

RevDate: 2020-04-01

Jones HD, Mateos E, Riutort M, et al (2020)

The identity of the invasive yellow-striped terrestrial planarian found recently in Europe: Caenoplana variegata (Fletcher amp; Hamilton, 1888) or Caenoplana bicolor (Graff, 1899)?.

Zootaxa, 4731(2):zootaxa.4731.2.2 pii:zootaxa.4731.2.2.

Terrestrial planarians with a dorsal yellow stripe and dark lateral surfaces and up to 15-20 cm long have been found in several countries in Europe, the earliest in 2008. They are similar to two species originally from Australia, Caenoplana variegata (Fletcher Hamilton, 1888) and C. bicolor (Graff, 1899), both described on external characters only, with no anatomical information. Careful reading suggests that there is no significant difference between the original descriptions. Further: observations on live specimens show considerable variation between individuals and in individuals over time and before and after feeding, negating any distinction between descriptions. Examination of three sectioned specimens shows considerable difference in sexual maturity, though one seems almost fully mature and the reproductive system is described. Molecular results show that specimens from the United Kingdom and Spain are of the same species. It is concluded that the planarians should be referred to as C. variegata, C. bicolor being a junior synonym.

RevDate: 2020-03-31

Sutor A, Schwarz S, FJ Conraths (2014)

The biological potential of the raccoon dog (Nyctereutes procyonoides, Gray 1834) as an invasive species in Europe-new risks for disease spread?.

Acta theriologica, 59(1):49-59.

Invasive wildlife species have the potential to act as additional host and vector species for infectious diseases. The raccoon dog (Nyctereutes procyonides), a carnivore species that has its origin in Asia, was taken as an example to demonstrate biological and ecological prerequisites which enables an invasive species to occupy a new habitat permanently. Studies conducted during the last 20 years identified a total of 35 species of endoparasites, five ectoparasites, six bacterial or protozoan species, and five viruses found in the subspecies Nyctereutes procyonoides ussuriensis in its original and newly occupied habitat or in Nyctereutes procyonoides koreensis in its original habitat, respectively. With reference to raccoon dogs impact as vector species and the relevance for human and animal health, we selected Trichinella spp., Echinococcus multilocularis, Francisella tularensis, rabies virus, and canine distemper virus for detailed description. Results of studies from Finland and Germany furthermore showed that biological characteristics of the raccoon dog make this carnivore an ideal host and vector for a variety of pathogens. This may result in a growing importance of this invasive species concerning the epidemiology of some transmissible diseases in Europe, including the hazard that the existence of autochthonous wildlife, particularly small populations, is endangered. Potential adverse effects on human and animal health in the livestock sector must also be taken into account. Especially with regard to its potential as a reservoir for zoonotic diseases, the raccoon dog should receive more attention in disease prevention and eradication strategies.

RevDate: 2020-04-01
CmpDate: 2020-04-01

Popkin G (2020)

Can 'sentinel trees' warn of devastating pests?.

Science (New York, N.Y.), 367(6485):1417.

RevDate: 2020-04-01
CmpDate: 2020-04-01

Peleg O, T Guy-Haim (2019)

A 150-year-old idea could hinder Suez Canal invasions.

Nature, 575(7782):287.

RevDate: 2020-03-31

Bojko J (2020)

The mitochondrial genome of UK (non-native) Dikerogammarus haemobaphes (Amphipoda: Gammaridae) informs upon Dikerogammarus evolution, invasions and associated microparasites.

Hydrobiologia, 847(1):229-242.

The amphipod Dikerogammarus haemobaphes is a high-risk carrier of parasites that impact wildlife in its non-native range. Studies using the mitochondrial genes, Cytochrome Oxidase Sub-Unit 1 (cox1) and small-subunit ribosomal RNA gene (16S), provide some nucleotide detail for understanding the evolution and phylogeography of this species. Despite this, the origins of the invasion remain unknown, as do the origins of its parasites. This study provides the full annotated mitochondrial genome (15,460 bp) of D. haemobaphes, consisting of 2 rRNAs, 24 tRNAs and 14 protein coding genes. Mitochondrial genes from the UK isolate are compared to existing data on NCBI and are used in a concatenated phylogenetic approach and identify D. haemobaphes as an early member of the Gammaridae (Amphipoda). Viral, bacterial, protistan and microsporidian parasites are present across the Gammaridae, including D. haemobaphes, suggesting the ancestor of the Gammaridae harboured related diseases, and that further screening of amphipods is likely to reveal further microparasite diversity. This correlation suggests that other gammarid invaders have the potential to harbour a range of microparasites. The mitochondrial genome of this species will act a resource to facilitate our understanding of geneflow, disease epidemiology and evolutionary history in this invasion-disease model.

RevDate: 2020-03-31
CmpDate: 2020-03-31

Germain RM, Srivastava D, AL Angert (2020)

Evolution of an inferior competitor increases resistance to biological invasion.

Nature ecology & evolution, 4(3):419-425.

Biodiversity is imperilled by the spatial homogenization of life on Earth. As new species invade ecological communities, there is urgent need to understand when native species might resist or succumb to interactions with new species. In the California Floristic Province, a global biodiversity hotspot, we show that populations of a native grass (Vulpia microstachys) have evolved to resist the competitive impacts of a dominant European invader (Bromus hordeaceus). Contrary to classic theory, which predicts that competing species co-evolve to differentiate their niches, our evidence is instead most consistent with the native species having evolved to better compete for those resources used by the invader, curtailing the invader's spread. Evolution to resist an invader was achieved despite populations interacting within a diverse background community (22 species 0.5 m-2 on average), refuting the oft-cited hypothesis that high diversity precludes the evolution of pairwise species interactions. Lastly, unlike studies that have explored the demographic consequences of evolution under competition, ours does so with naturally evolved populations. Our study highlights evolution as an underappreciated coexistence mechanism, acting to buffer species from extinction in the face of biological invasion.

RevDate: 2020-03-31
CmpDate: 2020-03-31

Del Pasqua M, Gambi MC, Caricato R, et al (2019)

Effects of short-term and long-term exposure to ocean acidification on carbonic anhydrase activity and morphometric characteristics in the invasive polychaete Branchiomma boholense (Annelida: Sabellidae): A case-study from a CO2 vent system.

Marine environmental research, 144:203-212.

The aim of this study was to test the effects of short- and long-term exposure to high pCO2 on the invasive polychaete Branchiomma boholense (Grube, 1878), (Sabellidae), through the implementation of a transplant experiment at the CO2 vents of the Castello Aragonese at the island of Ischia (Italy). Analysis of carbonic anhydrase (CA) activity, protein tissue content and morphometric characteristics were performed on transplanted individuals (short-term exposure) as well as on specimens resident to both normal and low pH/high pCO2 environments (long-term exposure). Results obtained on transplanted worms showed no significant differences in CA activity between individuals exposed to control and acidified conditions, while a decrease in weight was observed under short-term acclimatization to both control and low pH, although at low pH the decrease was more pronounced (∼20%). As regard individuals living under chronic exposure to high pCO2, the morphometric results revealed a significantly lower (70%) wet weight of specimens from the vents with respect to animals living in high pH/low pCO2 areas. Moreover, individuals living in the Castello vents showed doubled values of enzymatic activity and a significantly higher (50%) protein tissue content compared to specimens native from normal pH/low pCO2. The results of this study demonstrated that B. boholense is inclined to maintain a great homeostatic capacity when exposed to low pH, although likely at the energetic expense of other physiological processes such as growth, especially under chronic exposure to high pCO2.

RevDate: 2020-03-31
CmpDate: 2020-03-31

Souza GA, Moresca VO, Teixeira GM, et al (2018)

First record of the invasive tapeworm, Schyzocotyle acheilognathi (Pseudophyllidea; Bothriocephalidae) in native freshwater fish, Brazil.

Anais da Academia Brasileira de Ciencias, 90(3):2845-2849.

Schyzocotyle acheilognathi is a tapeworm cestode commonly found in native freshwater fishes from Asia. This cestode has low host specificity and for that reason it has been registered parasitizing more than 200 cultured and wild fish species, besides amphibians, reptiles and birds from different regions of the world. With a high pathogenic potential, S. acheilognathi may cause mortalities in highly infected fish. In South America, Schyzocotyle was reported in Cyprinus carpio from a Brazilian fish farm at the municipality of Cornélio Procópio, northern Paraná State and from the natural environment in C. carpio from Neuquen River, Patagonia, Argentina. So far, there has been no report of this parasite in South American native fishes. Herein we report the first occurrence of the invasive tapeworm S. acheilognathi in Rineloricaria pentamaculata (Siluriformes, Loricariidae), a native armored freshwater catfish from southern Brazil.

RevDate: 2020-03-30

Anderson SE, Closs GP, CD Matthaei (2020)

Agricultural Land-Use Legacy, The Invasive Alga Didymosphenia geminata and Invertebrate Communities in Upland Streams with Natural Flow Regimes.

Environmental management pii:10.1007/s00267-020-01285-6 [Epub ahead of print].

The integrity of freshwater ecosystems worldwide is under threat from agriculture and invasive species. Past agricultural activity can have persistent effects on aquatic diversity even decades after restoration, and the spread of invasive species is increasingly difficult to prevent due to globalisation. In the South Island of New Zealand, the invasive diatom Didymosphenia geminata (Didymo) causes nuisance blooms in streams. The impact of Didymo on stream invertebrate communities in upland streams with natural flow regimes remains poorly understood. We investigated the relationships between legacy effects of agriculture, Didymo and benthic invertebrate communities at 55 stream sites in Mahu Whenua, a 530 km2 conservation area comprising four former New Zealand high-country farms. The farms were destocked of sheep 4-9 years before stream sampling started. Kick-netting was used to collect macroinvertebrates from 7-23 streams within each farm to provide a land-use legacy gradient. Moreover, samples from 16 sites with clearly visible Didymo mats covering most of the stream bed (indicating high biomass and a dominant role in the biofilm) were compared with 39 sites without such Didymo mats. Total invertebrate taxon richness and EPT richness (taxon richness of larval mayflies, stoneflies and caddisflies) were lower in the stream catchments destocked most recently. When Didymo was present, relative EPT abundance was lower than when Didymo was absent, and Deleatidium mayflies decreased whereas midges and oligochaetes increased. These results highlight the need to look at past land-use practices when restoring high-country streams after agricultural impacts. They also show that Didymo can have negative effects on invertebrate communities in upland streams with natural flow regimes, a stream type previously overlooked in studies on this invasive diatom.

RevDate: 2020-03-29

Hernández-Castellano C, Rodrigo A, Gómez JM, et al (2020)

A new native plant in the neighborhood: effects on plant-pollinator networks, pollination, and plant reproductive success.

Ecology [Epub ahead of print].

Ecological communities are dynamic entities subjected to extinction/colonization events. Because species are connected through complex interaction networks, the arrival of a new species is likely to affect various species across the community, as observed in plant biological invasions. However, plant invasions usually represent extreme scenarios in which the community is strongly dominated by the alien species, confounding the effects of a change in species composition with a massive increase in floral resource availability. Our study addresses changes in plant community composition involving native species, a common phenomenon under the current climate change scenario in which plants are modifying their distribution ranges. We experimentally manipulated patches of a natural scrubland community by introducing a native plant (henceforth colonizing plant). To avoid introducing a disproportionate amount of floral resources we adjusted the number of flowers of the colonizing plant to the amount of floral resources locally available in each patch. We had two objectives: 1) to analyse the effects of the arrival of a new plant on the pollinator community, the rearrangement of plant-pollinator interactions and the structure of the plant-pollinator network; 2) to evaluate potential consequences for pollination and the reproductive success of resident plant species. The colonizing plant acted as a magnet species, attracting bumble bees and facilitating interactions to other plants through spill-over. The introduction of the colonizing plant also affected the structure of plant-pollinator networks (colonized networks were more generalized and more nested than control networks) and modified the arrangement of plant and pollinator species into modules. Ultimately, these changes resulted in higher heterospecific (but not conspecific) pollen deposition and had contrasting effects on the reproductive success of two resident plant species (higher fruit set and lower seed set, respectively). Our study shows that relationships between plants and pollinators are rapidly rearranged in response to novel situations (even when the new plant is not overly dominant), with important functional consequences on pollination and plant reproductive success. Our study establishes a link between network structure and pollination and plant reproductive success, which may be mediated by differences among pollinator species in foraging behavior.

RevDate: 2020-03-29

Dufour CMS, Clark DL, Herrel A, et al (2020)

Recent biological invasion shapes species recognition and aggressive behavior in a native species: a behavioral experiment using robots in the field.

The Journal of animal ecology [Epub ahead of print].

Invasive species are a worldwide threat to biodiversity. Yet, our understanding of biological invasions remains incomplete, partly due to the difficulty of tracking and studying behavioral interactions in recently created species interactions. We tested whether the interactions between the recently introduced invasive lizard Anolis cristatellus and the native Anolis oculatus in Dominica have led to changes in species recognition and aggressive behavior of the native species. The use of realistic robots allowed us to test the behavioral response of 131 A. oculatus males towards relevant and controlled conspecific vs. heterospecific stimuli, directly in the field and in two contexts (allopatry vs. sympatry). Our results show that species recognition evolved prior to sympatry in A. oculatus. Moreover, interspecific competition resulted in an increase in the time spent displaying and a divergence in the aggressive behavior of the native species toward conspecifics vs. heterospecifics. Inherent species recognition and higher aggressive behavior may limit species coexistence as they are expected to favor A. oculatus during territorial interactions with A. cristatellus. While more studies are needed to understand the causes of these behavioral shifts and their consequences on long-term species coexistence, the present study highlights the role of behavior as a first response to interspecific interactions.

RevDate: 2020-03-29

Petruzzella A, da S S R Rodrigues TA, van Leeuwen CHA, et al (2020)

Species identity and diversity effects on invasion resistance of tropical freshwater plant communities.

Scientific reports, 10(1):5626 pii:10.1038/s41598-020-62660-1.

Biotic resistance mediated by native plant diversity has long been hypothesized to reduce the success of invading plant species in terrestrial systems in temperate regions. However, still little is known about the mechanisms driving invasion patterns in other biomes or latitudes. We help to fill this gap by investigating how native plant community presence and diversity, and the presence of native phylogenetically closely related species to an invader, would affect invader Hydrilla verticillata establishment success in tropical freshwater submerged plant communities. The presence of a native community suppressed the growth of H. verticillata, but did not prevent its colonisation. Invader growth was negatively affected by native plant productivity, but independent of native species richness and phylogenetic relatedness to the invader. Native plant production was not related to native species richness in our study. We show that resistance in these tropical aquatic submerged plant communities is mainly driven by the presence and biomass of a native community independent of native species diversity. Our study illustrates that resistance provided by these tropical freshwater submerged plant communities to invasive species contrasts to resistance described for other ecosystems. This emphasizes the need to include understudied systems when predicting patterns of species invasiveness and ecosystem invasibility across biomes.

RevDate: 2020-03-29

Schulze V, Lurz PWW, Ferrari N, et al (2020)

Search for polyoma-, herpes-, and bornaviruses in squirrels of the family Sciuridae.

Virology journal, 17(1):42 pii:10.1186/s12985-020-01310-4.

BACKGROUND: Squirrels (family Sciuridae) are globally distributed members of the order Rodentia with wildlife occurrence in indigenous and non-indigenous regions (as invasive species) and frequent presence in zoological gardens and other holdings. Multiple species introductions, strong inter-species competition as well as the recent discovery of a novel zoonotic bornavirus resulted in increased research interest on squirrel pathogens. Therefore we aimed to test a variety of squirrel species for representatives of three virus families.

METHODS: Several species of the squirrel subfamilies Sciurinae, Callosciurinae and Xerinae were tested for the presence of polyomaviruses (PyVs; family Polyomaviridae) and herpesviruses (HVs; family Herpesviridae), using generic nested polymerase chain reaction (PCR) with specificity for the PyV VP1 gene and the HV DNA polymerase (DPOL) gene, respectively. Selected animals were tested for the presence of bornaviruses (family Bornaviridae), using both a broad-range orthobornavirus- and a variegated squirrel bornavirus 1 (VSBV-1)-specific reverse transcription-quantitative PCR (RT-qPCR).

RESULTS: In addition to previously detected bornavirus RNA-positive squirrels no more animals tested positive in this study, but four novel PyVs, four novel betaherpesviruses (BHVs) and six novel gammaherpesviruses (GHVs) were identified. For three PyVs, complete genomes could be amplified with long-distance PCR (LD-PCR). Splice sites of the PyV genomes were predicted in silico for large T antigen, small T antigen, and VP2 coding sequences, and experimentally confirmed in Vero and NIH/3T3 cells. Attempts to extend the HV DPOL sequences in upstream direction resulted in contiguous sequences of around 3.3 kilobase pairs for one BHV and two GHVs. Phylogenetic analysis allocated the novel squirrel PyVs to the genera Alpha- and Betapolyomavirus, the BHVs to the genus Muromegalovirus, and the GHVs to the genera Rhadinovirus and Macavirus.

CONCLUSIONS: This is the first report on molecular identification and sequence characterization of PyVs and HVs and the detection of bornavirus coinfections with PyVs or HVs in two squirrel species. Multiple detection of PyVs and HVs in certain squirrel species exclusively indicate their potential host association to a single squirrel species. The novel PyVs and HVs might serve for a better understanding of virus evolution in invading host species in the future.

RevDate: 2020-03-28

Escoriza D (2020)

Ship rats and island reptiles: patterns of co-existence in the Mediterranean.

PeerJ, 8:e8821 pii:8821.

Background: The western Mediterranean archipelagos have a rich endemic fauna, which includes five species of reptiles. Most of these archipelagos were colonized since early historic times by anthropochoric fauna, such as ship rats (Rattus rattus). Here, I evaluated the influence of ship rats on the occurrence of island reptiles, including non-endemic species.

Methodology: I analysed a presence-absence database encompassing 159 islands (Balearic Islands, Provence Islands, Corso-Sardinian Islands, Tuscan Archipelago, and Galite) using Bayesian-regularized logistic regression.

Results: The analysis indicated that ship rats do not influence the occurrence of endemic island reptiles, even on small islands. Moreover, Rattus rattus co-occurred positively with two species of non-endemic reptiles, including a nocturnal gecko, a guild considered particularly vulnerable to predation by rats. Overall, the analyses showed a very different pattern than that documented in other regions of the globe, possibly attributable to a long history of coexistence.

RevDate: 2020-03-28

Varón-González C, Fraimout A, Delapré A, et al (2020)

Limited thermal plasticity and geographical divergence in the ovipositor of Drosophila suzukii.

Royal Society open science, 7(1):191577 pii:rsos191577.

Phenotypic plasticity has been repeatedly suggested to facilitate adaptation to new environmental conditions, as in invasions. Here, we investigate this possibility by focusing on the worldwide invasion of Drosophila suzukii: an invasive species that has rapidly colonized all continents over the last decade. This species is characterized by a highly developed ovipositor, allowing females to lay eggs through the skin of ripe fruits. Using a novel approach based on the combined use of scanning electron microscopy and photogrammetry, we quantified the ovipositor size and three-dimensional shape, contrasting invasive and native populations raised at three different developmental temperatures. We found a small but significant effect of temperature and geographical origin on the ovipositor shape, showing the occurrence of both geographical differentiation and plasticity to temperature. The shape reaction norms are in turn strikingly similar among populations, suggesting very little difference in shape plasticity among invasive and native populations, and therefore rejecting the hypothesis of a particular role for the plasticity of the ovipositor in the invasion success. Overall, the ovipositor shape seems to be a fairly robust trait, indicative of stabilizing selection. The large performance spectrum rather than the flexibility of the ovipositor would thus contribute to the success of D. suzukii worldwide invasion.

RevDate: 2020-03-28

Gontero C, Fanelli A, Zanet S, et al (2020)

Exotic Species and Autochthonous Parasites: Trichostrongylus Retortaeformis in Eastern Cottontail.

Life (Basel, Switzerland), 10(4): pii:life10040031.

INTRODUCTION: A parasite community is usually well adapted and specific to the host species they co-evolved with. Although exotic pathogens infecting autochthonous species have been documented, the infection of an alien species with native parasites is rare in lagomorphs. Trichostrongylus retortaeformis is a nematode parasite infecting the small intestine of domestic and wild lagomorphs in Europe.

METHODS: Thirty-two Eastern cottontails from a naturalized population in Italy were processed to describe the gastrointestinal parasite community.

RESULTS AND DISCUSSIONS: T. retortaeformis is reported for the first time in the Eastern cottontail Sylvilagus floridanus introduced to Europe. The Eastern cottontail is an invasive lagomorph, living in sympatry with the autochthonous European brown hare in certain areas of Italy. This study provides new insights into the dynamics of parasite communities of native and alien lagomorph species in sympatric areas.

RevDate: 2020-03-27

Graham J, Jarnevich CS, Simpson A, et al (2011)

Federated or cached searches: Providing expected performance from multiple invasive species databases.

Frontiers of earth science, 5(2):111-119.

Invasive species are a universal global problem, but the information to identify them, manage them, and prevent invasions is stored around the globe in a variety of formats. The Global Invasive Species Information Network is a consortium of organizations working toward providing seamless access to these disparate databases via the Internet. A distributed network of databases can be created using the Internet and a standard web service protocol. There are two options to provide this integration. First, federated searches are being proposed to allow users to search "deep" web documents such as databases for invasive species. A second method is to create a cache of data from the databases for searching. We compare these two methods, and show that federated searches will not provide the performance and flexibility required from users and a central cache of the datum are required to improve performance.

RevDate: 2020-03-27

Havel JE, Kovalenko KE, Thomaz SM, et al (2015)

Aquatic invasive species: challenges for the future.

Hydrobiologia, 750(1):147-170.

Humans have effectively transported thousands of species around the globe and, with accelerated trade; the rate of introductions has increased over time. Aquatic ecosystems seem at particular risk from invasive species because of threats to biodiversity and human needs for water resources. Here, we review some known aspects of aquatic invasive species (AIS) and explore several new questions. We describe impacts of AIS, factors limiting their dispersal, and the role that humans play in transporting AIS. We also review the characteristics of species that should be the greatest threat for future invasions, including those that pave the way for invasions by other species ("invasional meltdown"). Susceptible aquatic communities, such as reservoirs, may serve as stepping stones for invasions of new landscapes. Some microbes disperse long distance, infect new hosts and grow in the external aquatic medium, a process that has consequences for human health. We also discuss the interaction between species invasions and other human impacts (climate change, landscape conversion), as well as the possible connection of invasions with regime shifts in lakes. Since many invaders become permanent features of the environment, we discuss how humans live with invasive species, and conclude with questions for future research.

RevDate: 2020-03-27

Dobelmann J, Felden A, PJ Lester (2020)

Genetic Strain Diversity of Multi-Host RNA Viruses that Infect a Wide Range of Pollinators and Associates is Shaped by Geographic Origins.

Viruses, 12(3): pii:v12030358.

Emerging viruses have caused concerns about pollinator population declines, as multi-host RNA viruses may pose a health threat to pollinators and associated arthropods. In order to understand the ecology and impact these viruses have, we studied their host range and determined to what extent host and spatial variation affect strain diversity. Firstly, we used RT-PCR to screen pollinators and associates, including honey bees (Apis mellifera) and invasive Argentine ants (Linepithema humile), for virus presence and replication. We tested for the black queen cell virus (BQCV), deformed wing virus (DWV), and Kashmir bee virus (KBV) that were initially detected in bees, and the two recently discovered Linepithema humile bunya-like virus 1 (LhuBLV1) and Moku virus (MKV). DWV, KBV, and MKV were detected and replicated in a wide range of hosts and commonly co-infected hymenopterans. Secondly, we placed KBV and DWV in a global phylogeny with sequences from various countries and hosts to determine the association of geographic origin and host with shared ancestry. Both phylogenies showed strong geographic rather than host-specific clustering, suggesting frequent inter-species virus transmission. Transmission routes between hosts are largely unknown. Nonetheless, avoiding the introduction of non-native species and diseased pollinators appears important to limit spill overs and disease emergence.

RevDate: 2020-03-27

Sumiyama D, Shimizu A, Kanazawa T, et al (2020)

Prevalence of Salmonella in green anoles (Anolis Carolinensis), an invasive alien species in Naha and Tomishiro Cities, Okinawa Main Island, Japan.

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

Here, we investigated the prevalence of Salmonellaenterica, with and without resistance to 17 common antimicrobial agents, in 706 green anoles (Anolis carolinensis) that were collected in Naha and Tomishiro Cities, Okinawa Main Island, Japan, between 2009 and 2014. Salmonella strains, including S. enterica Weltevreden and Enteritidis serovars, were identified in the large intestinal content samples extracted from 15 (2.1%) of the analyzed green anoles. No antimicrobial resistance was detected. Thus, the present study demonstrates that although the prevalence of Salmonella and the risk of its transmission from the green anoles to humans or other animals on Okinawa Main Island are relatively low, the green anole population nevertheless represents a potential source of Salmonella infection that could affect human health in this region.

RevDate: 2020-03-26

Biedrzycka A, Konopiński M, Hoffman E, et al (2020)

Comparing raccoon major histocompatibility complex diversity in native and introduced ranges: Evidence for the importance of functional immune diversity for adaptation and survival in novel environments.

Evolutionary applications, 13(4):752-767 pii:EVA12898.

The adaptive potential of invasive species is related to the genetic diversity of the invader, which is influenced by genetic drift and natural selection. Typically, the genetic diversity of invaders is studied with neutral genetic markers; however, the expectation of reduced diversity has not been consistently supported by empirical studies. Here, we describe and interpret genetic diversity at both neutral microsatellite loci and the immune-related MHC-DRB locus of native and invasive populations of raccoon to better understand of how drift and selection impact patterns of genetic diversity during the invasion process. We found that despite the loss of many MHC (major histocompatibility complex) alleles in comparison with native populations, functional MHC supertypes are preserved in the invasive region. In the native raccoon population, the number of supertypes within individuals was higher than expected under a neutral model. The high level of individual functional divergence may facilitate the adaptation to local conditions in the invasive range. In the invasive populations, we also detected increased population structure at microsatellites compared to the MHC locus, further suggesting that balancing selection is acting on adaptively important regions of the raccoon genome. Finally, we found that alleles known to exhibit resistance to rabies in the native range, Prlo-DRB*4, Prlo-DRB*16 and Prlo-DRB*102, were the most common alleles in the European populations, suggesting directional selection is acting on this locus. Our research shows empirical support for the importance of functional immune diversity for adaptation and survival in novel environments.

RevDate: 2020-03-26

Łagowska B, K Golan (2020)

An updated annotated checklist of scale insects (Hemiptera, Sternorrhyncha, Coccomorpha) of Poland.

ZooKeys, 918:65-81 pii:49126.

A checklist of scale insects recorded to date in Poland is presented. The data provided here are based on literature records and include the latest taxonomic and nomenclatural changes and updates on Coccomorpha reported in Poland. Changes in comparison with ScaleNet and Fauna Europaea electronic databases are also discussed. A total of 185 species belonging to 98 genera and 16 families are included in the list. Of this group, 47 species are alien introduced species and live only indoors, and one species, Pulvinaria floccifera (Westwood), develops both indoors and outdoors.

RevDate: 2020-03-26

Weiskopf SR, Rubenstein MA, Crozier LG, et al (2020)

Climate change effects on biodiversity, ecosystems, ecosystem services, and natural resource management in the United States.

The Science of the total environment pii:S0048-9697(20)31294-8 [Epub ahead of print].

Climate change is a pervasive and growing global threat to biodiversity and ecosystems. Here, we present the most up-to-date assessment of climate change impacts on biodiversity, ecosystems, and ecosystem services in the U.S. and implications for natural resource management. We draw from the 4th National Climate Assessment to summarize observed and projected changes to ecosystems and biodiversity, explore linkages to important ecosystem services, and discuss associated challenges and opportunities for natural resource management. We find that species are responding to climate change through changes in morphology and behavior, phenology, and geographic range shifts, and these changes are mediated by plastic and evolutionary responses. Responses by species and populations, combined with direct effects of climate change on ecosystems (including more extreme events), are resulting in widespread changes in productivity, species interactions, vulnerability to biological invasions, and other emergent properties. Collectively, these impacts alter the benefits and services that natural ecosystems can provide to society. Although not all impacts are negative, even positive changes can require costly societal adjustments. Natural resource managers need proactive, flexible adaptation strategies that consider historical and future outlooks to minimize costs over the long term. Many organizations are beginning to explore these approaches, but implementation is not yet prevalent or systematic across the nation.

RevDate: 2020-03-26
CmpDate: 2020-03-26

Ju Y, Liu H, He J, et al (2020)

Genetic diversity of Aoluguya Reindeer based on D-loop region of mtDNA and its conservation implications.

Gene, 733:144271.

Aoluguya Reindeer is the only reindeer population in China. In recent years, habitat loss and inbreeding have led to population decline, and population growth has been slow, maintaining a thousand or so. To better protect the Aoluguya Reindeer and improve its fecundity, we have introduced reindeer from Finland, crossbreeding help us to reach this goal. However, it is lacking in the study of genetic diversity of reindeer in China and Finland. Therefore, we used the partial sequences of the D-loop region of mitochondrial DNA to analyze the genetic diversity of Chinese reindeer (Aoluguya Reindeer) and the introduced Finnish reindeer, and identified twenty-six haplotypes, including nineteen in China, five in Finland, and two in Russia. There is no shared haplotype among them. The nucleotide diversity of Aoluguya Reindeer is 0.00752, which is significantly lower than that of reindeer in Finland and other countries. The haplotype and phylogenetic analysis show that reindeer from different geographical origins are not clustered completely according to geographical distribution. Aoluguya Reindeer populations and the introduced reindeer herds from Finland are all closely related to the reindeer from Russia. AMOVA analysis showed that there was significant differentiation between reindeer populations in China and Finland, and mismatch analysis showed that both populations had not experienced expansion. In this study, we identified the genetic diversity of Aoluguya Reindeer and the introduced reindeer, and provided a scientific basis for the conservation and breeding of Aoluguya Reindeer resources.

RevDate: 2020-03-27
CmpDate: 2020-03-27

Contento L, Hilhorst D, M Mimura (2018)

Ecological invasion in competition-diffusion systems when the exotic species is either very strong or very weak.

Journal of mathematical biology, 77(5):1383-1405.

Reaction-diffusion systems with a Lotka-Volterra-type reaction term, also known as competition-diffusion systems, have been used to investigate the dynamics of the competition among m ecological species for a limited resource necessary to their survival and growth. Notwithstanding their rather simple mathematical structure, such systems may display quite interesting behaviours. In particular, while for [Formula: see text] no coexistence of the two species is usually possible, if [Formula: see text] we may observe coexistence of all or a subset of the species, sensitively depending on the parameter values. Such coexistence can take the form of very complex spatio-temporal patterns and oscillations. Unfortunately, at the moment there are no known tools for a complete analytical study of such systems for [Formula: see text]. This means that establishing general criteria for the occurrence of coexistence appears to be very hard. In this paper we will instead give some criteria for the non-coexistence of species, motivated by the ecological problem of the invasion of an ecosystem by an exotic species. We will show that when the environment is very favourable to the invading species the invasion will always be successful and the native species will be driven to extinction. On the other hand, if the environment is not favourable enough, the invasion will always fail.

RevDate: 2020-03-27
CmpDate: 2020-03-27

Oba T, J Kigami (2018)

Why does invasion imply substitution? Beyond the paradigm of invasion fitness.

Journal of mathematical biology, 77(5):1493-1532.

Adaptive dynamics combines deterministic population dynamics of groups having different trait values and random process describing mutation and tries to predict the course of evolution of a species of interest. One of basic interests is to know which group survives, residents or mutants. By using invasion fitness as the primary tool, "invasion implies substitution" principle, IIS principle for short, has been established under the existence of a generating function in the sense of Brown and Vincent (Theor Popul Biol 31(1):140-166, 1987) and Vincent and Brown (Evolutionary game theory, natural selection, and darwinian dynamics. Cambridge University Press, Cambridge, 2005). This principle essentially says that the local gradient of invasion fitness ultimately determines the outcome of the competition. However, as we will see in this paper, even if a system is within the scope of IIS principle, its neighborhood always contains systems which are beyond this scope. In this paper, in order to overcome such a limitation, we establish a wider class of systems which is still reasonable as a model of evolution of a species. For our wider class, the notion of raw invasion fitness is introduced. In terms of raw invasion fitness, an explicit criterion for the existence of generating function and a counterpart of IIS principle are obtained. This enables us to discuss small perturbations of a system within or without the scope of generating functions/IIS principle. Eventually, we understand why invasion implies substitution, i.e. why the method using invasion fitness works well with the existence of generating function, from our broader point of view.

RevDate: 2020-03-27
CmpDate: 2020-03-27

Parsons TL (2018)

Invasion probabilities, hitting times, and some fluctuation theory for the stochastic logistic process.

Journal of mathematical biology, 77(4):1193-1231.

We consider excursions for a class of stochastic processes describing a population of discrete individuals experiencing density-limited growth, such that the population has a finite carrying capacity and behaves qualitatively like the classical logistic model Verhulst (Corresp Math Phys 10:113-121, 1838) when the carrying capacity is large. Being discrete and stochastic, however, our population nonetheless goes extinct in finite time. We present results concerning the maximum of the population prior to extinction in the large population limit, from which we obtain establishment probabilities and upper bounds for the process, as well as estimates for the waiting time to establishment and extinction. As a consequence, we show that conditional upon establishment, the stochastic logistic process will with high probability greatly exceed carrying capacity an arbitrary number of times prior to extinction.

RevDate: 2020-03-25

Zhou Q, Wang Y, Li X, et al (2020)

Geographical distribution and determining factors of different invasive ranks of alien species across China.

The Science of the total environment, 722:137929 pii:S0048-9697(20)31442-X [Epub ahead of print].

Determination of the geographical distribution and life-form spectra of alien species with different invasive abilities are essential to understand the process of invasion and to develop measures to manage alien species. Based on six classifications of Chinese alien species, environmental and social data, we determined species density, life-form spectrum of alien species, and the relationship between species density of alien species and climatic or social factors. The species density of alien species increased from the northwest to the southeast regions of China for all the six ranks. The boundary line between low and high species density of alien species was consistent with the dividing line of population density (the "Hu Line"). Mean annual precipitation was the most important factor for species density in malignant invaders, serious invaders, local invaders, and species requiring further observation (Ranks I, II, III, and V, respectively). Gross domestic product per square kilometer and annual minimum temperature were the most important factors in mild invaders and cultivated aliens (Ranks IV and VI, respectively). Annual and biennial herbs made up 52.9% to 71.2% of total species in Ranks I to IV; shrubs and trees 3.7% to 14.7%. The annual and biennial herbs were 35.5% and 32.6%, and the shrubs and trees were 25.3% and 31.6% in Ranks IV and VI. Results implied that precipitation was the most important factor on species density for the invasive alien species. However, social factors and temperature were the most important factors for the non-invasive alien species. The invasive alien species had a high proportion of annual and biennial herbs and non-invasive alien had a high proportion of shrubs and trees. It is important to understand the geographical distribution and life-form spectra of various invasive alien species for alien species controls.

RevDate: 2020-03-25

Zhang Q, Chen G, Shao L, et al (2020)

The hybridization between Sphagneticola trilobata (L.) Pruski and Sphagneticola calendulacea (L.) Pruski improved the tolerance of hybrid to cadmium stress.

Chemosphere, 249:126540 pii:S0045-6535(20)30733-5 [Epub ahead of print].

Hybridization is common between invasive and native species and may be accompanied by invasive evolution. The hybrid of Sphagneticola trilobata (alien invasive species) and Sphagneticola calendulacea (indigenous congener) was found in South China. According to previous studies, the hybrid performed weak environmental adaptability in comparison with parents. However, based on the results from this study, the hybridization significantly improved the tolerance of the hybrid to cadmium (Cd) stress (200 μmol L-1). Under Cd stress, the hybrid lines showed lowest level of oxidative damage and the highest level of photosynthetic efficiency. Compared with the parents, the hybrid utilized more active detoxification strategies, such as the cell walls of the leaves and roots adsorbed 88% and 95% Cd, respectively, reducing the amount of Cd entering cells; moreover, most of the Cd that entered cells was transformed into less toxic chemical forms through the reduction of the highly toxic chemical forms; furthermore, it accumulated a large number of phytochelatins to bind Cd2+ and reduced the damage of organelles by Cd2+. The results demonstrate that hybridization between S. trilobata and S. calendulacea improved the adaptability of the new hybrid species to Cd stress and may pose a greater threat to the survival of the native parent species in the presence of serious water and soil pollution.

RevDate: 2020-03-25
CmpDate: 2020-03-25

Huerta B, Chung-Davidson YW, Bussy U, et al (2020)

Sea lamprey cardiac mitochondrial bioenergetics after exposure to TFM and its metabolites.

Aquatic toxicology (Amsterdam, Netherlands), 219:105380.

Population control of invasive sea lamprey relies heavily on lampricide treatment of infested streams. The lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is thought to impair mitochondrial ATP production through uncoupling oxidative phosphorylation. However, the effect of TFM on the entire electron transport chain (complexes I to V) in the mitochondria is not clear. In addition, TFM is reduced in phase I metabolism by sea lamprey at higher levels than in other fish species. The effects of these TFM reductive metabolites on mitochondria have not been explored. In this study, we sought to examine the effects of TFM and its reductive metabolite amino-TFM (TFMa) on cardiac mitochondrial oxygen consumption and membrane potential to delineate potential mechanisms for toxicity. To determine if molecules with similar structure also exhibit similar effects on mitochondria, we used 4-nitro-3-methylphenol (NMP) and its reductive metabolites 4-amino-3-methylphenol (NMPa) and 4-nitroso-3-methylphenol (NMPn) for comparisons. We found that mitochondrial bioenergetics was heavily affected with increasing concentrations of TFM, NMP, and NMPa when complexes I and II of the electron transport chain were examined, indicating that the toxic action of these compounds was exerted not only by uncoupling complex V, but also affecting complexes I and II.

RevDate: 2020-03-25
CmpDate: 2020-03-25

Horricks RA, Tabin SK, Edwards JJ, et al (2019)

Organic ultraviolet filters in nearshore waters and in the invasive lionfish (Pterois volitans) in Grenada, West Indies.

PloS one, 14(7):e0220280.

Sunscreens and other personal care products use organic ultraviolet (UV) filters such as oxybenzone, 4-methylbenzylidene camphor, Padimate-O, and octyl methoxycinnamate to prevent damage to human skin. While these compounds are effective at preventing sunburn, they have a demonstrated negative effect on cells and tissues across taxonomic levels. These compounds have a relatively short half-life in seawater but are continuously re-introduced via recreational activities and wastewater discharge, making them environmentally persistent. Because of this, testing seawater samples for the presence of these compounds may not be reflective of their abundance in the environment. Bioaccumulation of organic ultraviolet filters in a high-trophic level predator may provide greater insight to the presence and persistence of these compounds. To address this, the present study collected seawater samples as well as muscle and stomach content samples from the invasive Pacific lionfish (Pterois volitans) in the nearshore waters of Grenada, West Indies to examine the use of lionfish as potential bioindicator species. Seawater and lionfish samples were collected at four sites that are near point sources of wastewater discharge and that receive a high number of visitors each year. Samples were tested for the presence and concentrations of oxybenzone, 4-methylbenzylidene camphor (4-MBC), Padimate-O, and octyl methoxycinnamate (OMC) using liquid chromatography-mass spectrometry. Oxybenzone residues were detected in 60% of seawater samples and OMC residues were detected in 20% of seawater samples. Seawater samples collected in the surface waters near Grenada's main beach had oxybenzone concentrations more than ten times higher than seawater samples collected in less frequently visited areas and the highest prevalence of UV filters in lionfish. Residues of oxybenzone were detected in 35% of lionfish muscle and 4-MBC residues were detected in 12% of lionfish muscle. Padimate-O was not detected in either seawater or lionfish samples. No organic UV filters were detected in lionfish stomach contents. Histopathologic examination of lionfish demonstrated no significant findings attributed to UV filter toxicity. These findings report UV filter residue levels for the first time in inshore waters in Grenada. Results indicate that lionfish may be bioaccumulating residues and may be a useful sentinel model for monitoring organic ultraviolet filters in the Caribbean Sea.

RevDate: 2020-03-23
CmpDate: 2020-03-23

Fletcher LM, Atalah J, BM Forrest (2018)

Effect of substrate deployment timing and reproductive strategy on patterns in invasiveness of the colonial ascidian Didemnum vexillum.

Marine environmental research, 141:109-118.

The colonial ascidian Didemnum vexillum is a high-profile marine invader, with a geographically widespread distribution after introductions to several temperate regions. D. vexillum has been the focus of several eradication and control programmes globally and the need for specific biological knowledge that relates to establishment processes, persistence, impacts and potential for spread remains. The present study describes temporal patterns of D. vexillum percent cover on experimental substrates over 1.5-years in relation to seasonality of substratum availability, in conjunction with key physical (i.e. temperature and sedimentation) and biological factors (i.e. interspecific competition) at two sites in New Zealand. Colonies showed large fluctuations in percent cover between the two study sites and with reference to timing of bare substratum availability. Colonies generally exhibited an initial lag phase, with peak levels of D. vexillum cover reached during the second summer or autumn post-deployment. The long-term competitive dominance of colonies founded from the reattachment of fragments, as opposed to ambient larval recruitment alone, was also investigated. Increases in colony size as a result of ambient recruitment alone were initially much slower. However, after 12-months colony cover exceeded that of plates inoculated with fragments, suggesting the benefit of the apparent competitive dominance conferred by fragment inoculation is restricted to the early establishment phase. This information will provide increased understanding of the population dynamics of this species, as well as assist in the implementation of effective management strategies through knowledge of environmental drivers of prolific infestations.

RevDate: 2020-03-24

Shackleton RT, Petitpierre B, Pajkovic M, et al (2020)

Integrated Methods for Monitoring the Invasive Potential and Management of Heracleum mantegazzianum (giant hogweed) in Switzerland.

Environmental management pii:10.1007/s00267-020-01282-9 [Epub ahead of print].

Biological invasions are a major driver of human-induced global environmental change. This makes monitoring of potential spread, population changes and control measures necessary for guiding management. We illustrate the value of integrated methods (species distribution modelling (SDM), plant population monitoring and questionnaires) for monitoring and assessing invasions of Heracleum mantegazzianum (giant hogweed) over time in Switzerland. SDMs highlighted the potential spread of the species, uncovered ecological mechanisms underlying invasions and guided monitoring at a regional level. We used adaptive and repeat plant sampling to monitor invasive population status and changes, and assess the effectiveness of H. mantegazzianum management over three periods (2005, 2013 and 2018) within the pre-Alps, Vaud. We also conducted questionnaire surveys with managers and the public. Multiscale modelling, and integrating global and regional SDMs, provided the best predictions, showing that H. mantegazzianum can potentially invade large parts of Switzerland, especially below 2 000 m a.s.l. Over time, populations of invasive H. mantegazzianum in the Vaud pre-Alps have declined, which is most likely due to a sharp rise in management uptake post 2007 (7% of municipalities before 2007 to 86% in 2018). The level of known invasive populations has decreased by 54% over time. Some municipalities have even successfully eradicated H. mantegazzianum within their borders. However, a few areas, particularly in the rural, higher-altitude municipalities, where management was not implemented effectively, populations have expanded, which could hamper control efforts at lower altitudes. We provide encouraging evidence that control measures can be effective in reducing plant invasions with long-term commitment, as well as a good template for using integrated methodological approaches to better study and monitor invasive alien species.

RevDate: 2020-03-24

Despland E, PG Santacruz (2020)

Top-down and bottom-up controls on an herbivore on a native and introduced plant in a tropical agricultural landscape.

PeerJ, 8:e8782 pii:8782.

The recent introduction in a tropical agricultural environment of a weedy open-habitat plant (Solanum myriacanthum) and subsequent host range expansion of a common forest-edge butterfly (Mechanitis menapis) onto that plant provides an opportunity to examine reconfiguration of tritrophic networks in human-impacted landscapes. The objectives of this study were (1) determine if the caterpillars on the exotic host are more or less limited by plant defenses (bottom-up forces) and if they experience enemy release (decrease of top-down pressure) and (2) define how anthropic open pasture habitat influences the herbivore's tritrophic niche. Field and laboratory monitoring of larval survival and performance on a native (Solanum acerifolium) host plant and the exotic (S. myriacanthum) host plant were conducted in the Mindo Valley, Ecuador. Plant physical defenses were also measured. Results showed that larval mortality was mostly top-down on S. acerifolium, linked to parasitism, but mostly bottom-up on S. myriacanthum, possibly linked to observed increased plant defenses. Thus, in the absence of co-evolved relationships, herbivores on the exotic host experienced little top-down regulation, but stronger bottom-up pressures from plant defenses. These findings provide a rare empirical example of enemy-free space as a mechanism underlying host-range expansion. S. myriacanthum was less colonized in open pastures than in semi-shaded habitats (forest edges, thickets): fewer eggs were found, suggesting limited dispersal of adult butterflies into the harsh open environments, and the survival rate of first instar larvae was lower than on semi-shaded plants, likely linked to the stronger defenses of sun-grown leaves. These findings show how environmental conditions modulate the rewiring of trophic networks in heavily impacted landscapes, and limit a biocontrol by a native herbivore on an invasive plant in open habitats.

RevDate: 2020-03-24

Lundgren EJ, Ramp D, Rowan J, et al (2020)

Introduced herbivores restore Late Pleistocene ecological functions.

Proceedings of the National Academy of Sciences of the United States of America pii:1915769117 [Epub ahead of print].

Large-bodied mammalian herbivores dominated Earth's terrestrial ecosystems for several million years before undergoing substantial extinctions and declines during the Late Pleistocene (LP) due to prehistoric human impacts. The decline of large herbivores led to widespread ecological changes due to the loss of their ecological functions, as driven by their unique combinations of traits. However, recently, humans have significantly increased herbivore species richness through introductions in many parts of the world, potentially counteracting LP losses. Here, we assessed the extent to which introduced herbivore species restore lost-or contribute novel-functions relative to preextinction LP assemblages. We constructed multidimensional trait spaces using a trait database for all extant and extinct mammalian herbivores ≥10 kg known from the earliest LP (∼130,000 ybp) to the present day. Extinction-driven contractions of LP trait space have been offset through introductions by ∼39% globally. Analysis of trait space overlap reveals that assemblages with introduced species are overall more similar to those of the LP than native-only assemblages. This is because 64% of introduced species are more similar to extinct rather than extant species within their respective continents. Many introduced herbivores restore trait combinations that have the capacity to influence ecosystem processes, such as wildfire and shrub expansion in drylands. Although introduced species have long been a source of contention, our findings indicate that they may, in part, restore ecological functions reflective of the past several million years before widespread human-driven extinctions.

RevDate: 2020-03-23
CmpDate: 2020-03-23

Köhnke MC, H Malchow (2019)

Wave pinning in competition-diffusion models in variable environments.

Journal of theoretical biology, 461:204-214.

Numerical results on conditions for the emergence of propagation failure of diffusive fronts in two-species competition models for populations with either logistic growth or strong Allee effect are presented. Particularly, the stability against environmental perturbations is investigated. Two different density dependencies of the noise intensities are considered. They mimic a differential functional response of the competitors to the variable environment. Assuming classical linearly density-dependent noise intensities, stochastic wave pinning can occur. This is an ecologically important finding regarding biological invasion as it means that the invasion speed can be reduced by environmental perturbations even yielding a reversal of the invasion wave. However, this depends on the form of the functional per-capita noise response.

RevDate: 2020-02-06
CmpDate: 2020-02-06

Aplasca AC, Titus V, Ossiboff RJ, et al (2019)


Journal of wildlife diseases, 55(2):352-362.

The Bronx River in Bronx, New York, US spans an area of significant human development and has been subject to historic and ongoing industrial contamination. We evaluated the health of freeranging native common snapping turtles (Chelydra serpentina) and nonnative invasive red-eared sliders (Trachemys scripta) in a segment of the Bronx River between May and July 2012. In 18 snapping turtles and nine sliders, complete physical examinations were performed, ectoparasites collected, and blood was analyzed for contaminants (mercury, thallium, cadmium, arsenic, lead, selenium, oxychlordane, alpha-chlordane, dieldrin, DDD, DDE, polychlorinated biphenyls). Complete blood counts and the presence of hemoparasites were determined in 16 snapping turtles and nine sliders. Swabs of the choana and cloaca were screened for ranavirus, adenovirus, herpesvirus, and Mycoplasma spp. by PCR in 39 snapping turtles and 28 sliders. Both turtle species exhibited bioaccumulation of various environmental contaminants, particularly organochlorines and polychlorinated biphenyls. Molecular screening revealed a unique herpesvirus in each species. A Mycoplasma sp. previously isolated from emydid turtles was detected in red-eared sliders while a unique Mycoplasma sp. was identified in common snapping turtles. Ranaviruses and adenoviruses were not detected. Our study established a baseline health assessment to which future data can be compared. Moreover, it served to expand the knowledge and patterns of health markers, environmental contaminants, and microorganisms of freeranging chelonians.

RevDate: 2020-03-21

Forrester MB, Layton GM, SM Varney (2020)

Melia Azedarach Ingestions Reported to Texas Poison Centers.

The Journal of emergency medicine pii:S0736-4679(20)30013-5 [Epub ahead of print].

BACKGROUND: Melia azedarach, also known as the chinaberry tree, is native to Southeast Asia and northern Australia but has become an invasive species in the United States. M. azedarach contains limonoid tetranotriterpenes, found in highest concentrations in its berries. Ingestion has been reported to result in adverse clinical effects affecting the gastrointestinal, cardiovascular, respiratory, and neurologic systems.

OBJECTIVE: The objective of this investigation was to describe M. azedarach ingestions in Texas.

METHODS: Cases were M. azedarach ingestions reported to Texas poison centers from 2000-2018. The distribution of cases was determined for various factors related to patient demographics, ingestion circumstances, management, and outcome.

RESULTS: Of 990 total M. azedarach ingestions, 87.4% involved the berry. There was a seasonal pattern with 42.9% reported between March and May. The patients were male in 55.1% of cases; 86.6% of the patients were ≤5 years of age. Patients were managed outside of a health care facility in 89.9% of cases; 95.2% of the ingestions resulted in no or at most minor clinical effects. The most frequently reported clinical effects were gastrointestinal (8.9%) and neurologic (2.1%). The most common treatments were dilution (67.2%) and food/snack (16.8%).

CONCLUSION: In this study that focused on M. azedarach ingestions reported to Texas poison centers, the ingestions tended to involve berries. Most of the patients were young children. The ingestions often occurred between March and May. The ingestions typically were managed outside of a health care facility and did not result in serious outcomes. The most common clinical effects were gastrointestinal and neurologic.

RevDate: 2020-03-20

Friedemann AER, Andernach L, Jungnickel H, et al (2020)

Phosphine fumigation - Time dependent changes in the volatile profile of table grapes.

Journal of hazardous materials, 393:122480 pii:S0304-3894(20)30469-6 [Epub ahead of print].

Industrial and agricultural goods are fumigated in transport containers in order to control pest infestations and to avoid the transmission of alien species. Phosphine is increasingly used prior to the export as fumigant for table grapes, fruit cultures and dried fruits to control active table grapevine insect pests. Less knowledge exists for fumigants about the desorption time of toxic gases and factors that affect the composition of the fumigated good. Therefore, red and white table grapes (´Thompson seedless´, ´Scarlotta´ and ´Flame seedless´) were chosen to represent the allowed group of phosphine fumigated foods and were treated with a concentration of 2000 vpm phosphine (PH3) at different temperatures. In the present study, sorption and desorption behavior of PH3 by table grapes and possible changes in their VOC (volatile organic compounds) profiles were investigated. The PH3 concentration was monitored before and after the fumigation process and was determined under the maximum residue level 0.005 ppm after 35 days. The adsorbed amount of PH3 was not influenced by fumigation parameters. For analysis of the influences on the volatile profile after fumigation, a headspace solid-phase micro-extraction coupled to gas chromatography mass spectrometry (HS-SPME-GC/MS) was used. Small differences in volatile profiles of fumigated and subsequently outgassed table grapes compared to non-fumigated table grapes could be observed. A slight influence on the aldehyde group directly after fumigation could be perceived by a decrease of hex-2-en-1-ol and 1- hexanol in PH3-treated table grapes. The concentrations of both compounds increase again after completion of the desorption process. On the other hand terpenes are not significantly influenced by the fumigation process. Overall these changes are likely to affect table grape aroma characteristics directly after a treatment with PH3 and it could be demonstrated that phosphine alters the volatile profile of fumigated table grapes qualitatively and quantitatively.

RevDate: 2020-03-20

Grignon-Dubois M, De Montaudouin X, B Rezzonico (2020)

Flavonoid pattern inheritance in the allopolyploid Spartina anglica - Comparison with the parental species S. maritima and S. alterniflora.

Phytochemistry, 174:112312 pii:S0031-9422(19)30849-0 [Epub ahead of print].

The invasive species Spartina anglica arose in Europe by a cross between the Afro-European species S. maritima (native, paternal ancestor) and the introduced North American S. alterniflora (invasive, maternal ancestor). Aqueous methanolic extracts were prepared from plant tissue for chemotaxonomical comparison between the three species and determination of the phenolic pattern inheritance in S. anglica. A total of 20 phenolic compounds were detected in the aerial tissues of S. anglica and S. alterniflora, but only seven in S. maritima. They were isolated from their respective crude extracts, and their structures were determined according to spectroscopic data analysis and chemical evidence. They all belong to the flavonoid class, with 13 of them identified as C-glycoflavonoid and seven as O-glycoflavonoid. All these products were detected for the first time from S. anglica, fourteen of them for the first time from S. alterniflora, and three of them for the first time from S. maritima. The individual concentrations in the three species were determined by quantitative HPLC. The two parental species were found to differ markedly in their foliar phenolic fingerprint, whereas that of S. anglica showed a clear maternal dominance. Eight of the fourteen major compounds identified were of maternal origin among which, six were over-expressed, only three were from paternal origin but under-regulated, while two originated from the two parents. As far as we know, this work represents the first exhaustive report of the phenolic fingerprints of S. alterniflora and S. anglica and of the phenolic pattern inheritance in S. anglica. The similarity in the phenolic chemistry of the introduced and invasive S. alterniflora to its progeny could play a role in the physiological vigour and invasion success of S. anglica. This work provide a foundation for further studies, considering the reported biological activities of C-glycosidic flavonoids and tricin derivatives, and the lack of knowledge of the ecological chemistry of the genus Spartina.

RevDate: 2020-03-20

Stone CM, Zuo Z, Li B, et al (2020)

Spatial, Temporal, and Genetic Invasion Dynamics of Aedes albopictus (Diptera: Culicidae) in Illinois.

Journal of medical entomology pii:5804183 [Epub ahead of print].

The spread of the Asian tiger mosquito, Aedes albopictus Skuse, throughout the United States has implications for the transmission potential of vector-borne diseases. We used a 30-yr data set of occurrence records in Illinois and developed a hierarchical Bayesian model to shed light on the patterns and processes involved in the introduction and expansion along the northern edge of the geographic range of this species. We also collected specimens from 10 locations and sequenced a segment of their mitochondrial COI genes to assess possible introduction sources and geographic patterns in genetic variation present within contemporary populations. We documented an increase in the number of observations throughout the southern and central parts of Illinois over the study period. The process through which this spread occurred is likely only partially due to local dispersal. The probability of successfully overwintering was likewise low, but both these parameters increased over the study period. This suggests that the presence of Ae. albopictus has been largely due to repeated introductions, but that in recent years populations may have become established and are leading to an increase in locally driven dispersal. There was considerable genetic diversity among populations in Illinois, with 13 distinct haplotypes present in 10 sampling locations, several of which matched haplotypes previously found to be present in locations such as Texas or Japan. Further research is needed to understand how the combination of continued propagule pressure and establishment of populations are driving the increase and expansion of this invasive mosquito along its northern distribution limit.

RevDate: 2020-03-20

Battiston R, Amerini R, Di Pietro W, et al (2020)

A new alien mantis in Italy: is the Indochina mantis Hierodula patellifera chasing the train for Europe?.

Biodiversity data journal, 8:e50779 pii:50779.

The presence of the Indochina mantis Hierodula patellifera (Mantidae, Mantinae) as a new alien species in Italy is reported, with the description of the first stable macro-population in Europe. This macro-population shows a wide distribution, comprising several fragmented and reproducing sub-populations in Northern Italy and one in Southern France. Specimens and individuals were collected or observed on trees and ornamentals in urban ecosystems with the help of citizen science. A spatial analysis (Average Nearest Neighbour) was undertaken to characterise the present distribution pattern, evidencing the hot spots of arrival and the local spreading process. The random pattern of presence in the local urban textures and the resistance of this species to the challenging North Italian climate, are here discussed in the perspective of a future expansion to central and Northern Europe, using probably the main railways to arrive at depots and cities, travelling with Asian goods. Identification characters are also presented to separate this alien species from the other species of the subfamily Mantinae, native or introduced, present in Europe.

RevDate: 2020-03-20
CmpDate: 2020-03-20

Killi N, Tarkan AS, Kozic S, et al (2020)

Risk screening of the potential invasiveness of non-native jellyfishes in the Mediterranean Sea.

Marine pollution bulletin, 150:110728.

The aim of the present study was to risk screen 45 jellyfish species (30 hydromedusae, 14 scyphomedusae, one cubomedusa) for their potential invasiveness in the Mediterranean Sea to aid managers in making informed decisions on targeting appropriate species for management. Using the Aquatic Species Invasiveness Screening Kit (AS-ISK), calibrated basic and climate-change threshold assessment scores of 6.5 and 12.5, respectively, were identified for distinguishing reliably between species that pose 'low-to-medium' and 'high' risk of becoming invasive in the risk assessment area. Using these thresholds, 16 species were classified as high risk, 23 as medium risk and six as low risk under current climate conditions. Whereas, under future climate conditions, 13, 30 and two species, respectively, were classified as high, medium and low risk, respectively. Upside-down jellyfish Cassiopea andromeda, Australian spotted jellyfish Phyllorhiza punctata, sea nettle Chrysaora quinquecirrha and Rhopilema nomadica were the highest-scoring species, with the maximum increase in risk score under predicted climate change conditions being achieved by C. andromeda.

RevDate: 2020-03-20
CmpDate: 2020-03-20

LeBrun EG, Plowes RM, Folgarait PJ, et al (2019)

Ritualized aggressive behavior reveals distinct social structures in native and introduced range tawny crazy ants.

PloS one, 14(11):e0225597.

How workers within an ant colony perceive and enforce colony boundaries is a defining biological feature of an ant species. Ants fall along a spectrum of social organizations ranging from single-queen, single nest societies to species with multi-queen societies in which workers exhibit colony-specific, altruistic behaviors towards non-nestmate workers from distant locations. Defining where an ant species falls along this spectrum is critical for understanding its basic ecology. Herein we quantify queen numbers, describe intraspecific aggression, and characterize the distribution of colony sizes for tawny crazy ant (Nylanderia fulva) populations in native range areas in South America as well as in their introduced range in the Southeastern United States. In both ranges, multi-queen nests are common. In the introduced range, aggressive behaviors are absent at all spatial scales tested, indicating that within the population in the Southeastern United States N. fulva is unicolonial. However, this contrasts strongly with intraspecific aggression in its South American native range. In the native range, intraspecific aggression between ants from different nests is common and ritualized. Aggression is typically one-sided and follows a stereotyped sequence of escalating behaviors that stops before actual fighting occurs. Spatial patterns of non-aggressive nest aggregation and the transitivity of non-aggressive interactions demonstrate that results of neutral arena assays usefully delineate colony boundaries. In the native range, both the spatial extent of colonies and the average number of queens encountered per nest differ between sites. This intercontinental comparison presents the first description of intraspecific aggressive behavior for this invasive ant and characterizes the variation in colony organization in the native-range, a pre-requisite to a full understanding of the origins of unicoloniality in its introduced range.

RevDate: 2020-03-20
CmpDate: 2020-03-20

Hayer S, Bick A, Brandt A, et al (2019)

Coming and going - Historical distributions of the European oyster Ostrea edulis Linnaeus, 1758 and the introduced slipper limpet Crepidula fornicata Linnaeus, 1758 in the North Sea.

PloS one, 14(10):e0224249.

Natural history collections are fundamental for biodiversity research as well as for any applied environment-related research. These collections can be seen as archives of earth´s life providing the basis to address highly relevant scientific questions such as how biodiversity changes in certain environments, either through evolutionary processes in a geological timescale, or by man-made transformation of habitats throughout the last decades and/or centuries. A prominent example is the decline of the European flat oyster Ostrea edulis Linneaus, 1758 in the North Sea and the concomitant invasion of the common limpet slipper Crepidula fornicata, which has been implicated to have negative effects on O. edulis. We used collections to analyse population changes in both species in the North Sea. In order to reconstruct the change in distribution and diversity over the past 200 years, we combined the temporal and spatial information recorded with the collected specimens contained in several European natural history collections. Our data recover the decline of O. edulis in the North Sea from the 19th century to the present and the process of invasion of C. fornicata. Importantly, the decline of O. edulis was nearly completed before C. fornicata appeared in the North Sea, suggesting that the latter had nothing to do with the local extinction of O. edulis in the North Sea.

RevDate: 2020-03-20
CmpDate: 2020-03-20

Kim KH, Kim JS, Cho HJ, et al (2019)

Identification of Key Genes for the Precise Classification between Solenopsis invicta and S. geminata Facilitating the Quarantine Process.

Genes, 10(10):.

One of the 100 worst invasive exotic species, Solenopsis invicta (red imported fire ant), has the possibility to induce an allergic reaction that may eventually cause death from its aggressive stinging. In 2017, S. invicta was found at a container yard in Gamman Port, Busan, South Korea for the first time. It may result in an infestation of fire ants in the Korean environment. After this incident, sensitive quarantine procedures are required to detect possible contamination of fire ants in imported containers. However, currently, fire ant identification relies on phenotypic characteristics. This requires highly trained experts for identification and there are not enough to cover all imported containers. Here, we develop a key molecular marker to distinguish S. invicta from others using the whole genome sequence (WGS) of collected S. invicta from Gamman Port and NCBI-deposited WGS data of S.invicta and S. geminata. The consolidated genotypes of Solenopsis genus successfully indicate the distinguishable gene. The gel-based experimental validation confirmed expected classification and the developed cleaved amplified polymorphic sequences (CAPS) marker also gave a consistent result. Using the CAPS marker derived from our consolidated genotypes, the samples collected from containers in several ports can be easily tested by PCR in a few hours. The quick and easy test would increase not only the labor efficiency but also the environmental safety from fire ants.

RevDate: 2020-03-19

Gardner ST, Assis VR, Smith KM, et al (2020)

Innate immunity of Florida cane toads: how dispersal has affected physiological responses to LPS.

Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology pii:10.1007/s00360-020-01272-7 [Epub ahead of print].

Physiological tradeoffs occur in organisms coping with their environments, which are likely to increase as populations reach peripheries of established ranges. Invasive species offer opportunities to study tradeoffs that occur, with many hypotheses focusing on how immune responses vary during dispersal. The cane toad (Rhinella marina) is a well-known invasive species. Populations near the expanding edge of the Australian invasion have altered immune responses compared to toads from longer-established core populations, although this has not been well-documented for Florida populations. In this study, cane toads from a northern edge [New Port Richey (NPR)] and southern core (Miami) population in Florida were collected and injected with lipopolysaccharide (LPS) to compare immune responses. Core population individuals injected with LPS showed greater metabolic increases compared to their baseline rates that were higher compared to those from the edge population. In addition, LPS-injected core individuals had different circulating leukocyte profiles compared to saline-injected cane toads while edge individuals did not. There was a significant interaction between plasma bacteria-killing capability (BKA) and treatment, such that BKA decreased with time in saline compared to LPS-injected individuals, and saline-injected toads from the edge population had lower BKA compared to LPS-injected edge toads at 20 h post-injection. There was also a significant interaction between location and time on circulating corticosterone (CORT) levels following injections with saline or LPS, with CORT decreasing more with time in core population toads. The differential CORT response indicates that differential stress responses contribute to the tradeoffs observed with immunity and dispersal.

RevDate: 2020-03-19

Mahar JE, Shi M, Hall RN, et al (2020)

Comparative analysis of RNA virome composition in rabbits and associated ectoparasites.

Journal of virology pii:JVI.02119-19 [Epub ahead of print].

Ectoparasites play an important role in virus transmission among vertebrates. Little, however, is known about the nature of those viruses that pass between invertebrates and vertebrates. In Australia, flies and fleas support the mechanical transmission of two viral biological controls against wild rabbits - rabbit hemorrhagic disease virus (RHDV) and myxoma virus. We compared virome compositions in rabbits and these ectoparasites, sequencing total RNA from multiple tissues and gut contents of wild rabbits, fleas collected from these rabbits, and flies trapped sympatrically. Meta-transcriptomic analyses identified 50 novel viruses from multiple RNA virus families. Rabbits and their ectoparasites were characterized by markedly different viromes, with virus abundance greatest in flies. Although viral contigs from six virus families/groups were found in both rabbits and ectoparasites, they clustered in distinct host-dependent lineages. A novel calicivirus and picornavirus detected in rabbit cecal content were vertebrate-specific: the newly detected calicivirus was distinct from known rabbit caliciviruses, while the picornavirus clustered with sapeloviruses. Several picobirnaviruses were also identified that fell in diverse phylogenetic positions, compatible with the idea that they are associated with bacteria. Further comparative analysis revealed that the remaining viruses found in rabbits, and all those from ectoparasites, were likely associated with invertebrates, plants and co-infecting endosymbionts. While no full genomes of vertebrate-associated viruses were detected in ectoparasites, small numbers of reads from rabbit astrovirus, RHDV and other lagoviruses were present in flies. This supports a role for flies in the mechanical transmission of RHDV, while their involvement in astrovirus transmission merits additional exploration.ImportanceEctoparasites play an important role in the transmission of many vertebrate-infecting viruses, including Zika and dengue viruses. Although it is becoming increasingly clear that invertebrate species harbor substantial virus diversity, it is unclear how many of the viruses carried by invertebrates have the potential to infect vertebrate species. We used the European rabbit (Oryctolagus cuniculus) as a model species to compare virome compositions in a vertebrate host and known associated ectoparasite mechanical vectors, in this case, fleas and blowflies. In particular, we aimed to infer the extent of viral transfer between these distinct types of host. Our analysis revealed that despite extensive viral diversity in both rabbits and associated ectoparasites, and the close interaction of these vertebrate and invertebrate species, biological viral transmission from ectoparasites to vertebrate species is rare. We did, however, find evidence to support the role of blowflies in transmitting viruses without active replication in the insect.

RevDate: 2020-03-19
CmpDate: 2020-03-19

Geraldi NR, Anton A, Santana-Garcon J, et al (2020)

Ecological effects of non-native species in marine ecosystems relate to co-occurring anthropogenic pressures.

Global change biology, 26(3):1248-1258.

Predictors for the ecological effects of non-native species are lacking, even though such knowledge is fundamental to manage non-native species and mitigate their impacts. Current theories suggest that the ecological effects of non-native species may be related to other concomitant anthropogenic stressors, but this has not been tested at a global scale. We combine an exhaustive meta-analysis of the ecological effects of marine non-native species with human footprint proxies to determine whether the ecological changes due to non-native species are modulated by co-occurring anthropogenic impacts. We found that non-native species had greater negative effects on native biodiversity where human population was high and caused reductions in individual performance where cumulative human impacts were large. On this basis we identified several marine ecoregions where non-native species may have the greatest ecological effects, including areas in the Mediterranean Sea and along the northwest coast of the United States. In conclusion, our global assessment suggests coexisting anthropogenic impacts can intensify the ecological effects of non-native species.

RevDate: 2020-03-19
CmpDate: 2020-03-19

Lamsal A, Devkota MP, Shrestha DS, et al (2019)

Seed germination ecology of Ageratum houstonianum: A major invasive weed in Nepal.

PloS one, 14(11):e0225430.

In recent years, spread of invasive alien plant species (IAPS) has been a major concern in Nepal. One such IAPS is Ageratum houstonianum, an Asteraceae, that is a prolific seed producer and difficult-to-control in farmland and various ecological regions causing crop yield and biodiversity losses. However, very little information is available on the germination biology and ecology of this species. Therefore, experiments were conducted to assess the effect of water stress, pH level, and light requirement on seed germination, and the effect of seed burial depth on seedling emergence. Water stress was simulated by polyethylene glycol solutions ranging from 0-5.56 MPa and pH solutions ranging from 4 to 9 were prepared using hydrochloric acid and sodium hydroxide. Germination tests were conducted in petri dishes lined with filter paper and placed in a controlled environment chamber set at 20° C. Light requirement comparisons were made by having petri dishes wrapped with aluminum foil or left unwrapped. Seedling emergence was evaluated by placing seeds at depths ranging from 0 to 20 mm in the soil. Results indicated that this species was moderately drought-tolerant because germination ceased beyond 0.51 MPa. Greater germination occurred at neutral to acidic than at alkaline pH levels. The seeds were positively photoblastic because no germination occurred under dark condition. No seedlings emerged from seeds placed more than 2 mm deep in the soil, indicating that this is a primarily surface germinating species. These findings will help predict future invasions and in development of management strategies for this IAPS.

RevDate: 2020-03-18

Maldonado-Márquez A, Contador T, Rendoll-Cárcamo J, et al (2020)

Southernmost distribution limit for endangered Peladillas (Aplochiton taeniatus) and non-native coho salmon (Oncorhychus kisutch) co-existing within the Cape Horn Biosphere Reserve, Chile.

Journal of fish biology [Epub ahead of print].

The Cape Horn Biosphere Reserve, one of the last wild areas of the planet, is not exempt from the pressures of global change, such as non-native species introductions. During 2018 and 2019 we studied the Róbalo river basin in order to update the diversity and distribution of fishes. Here, we report for the first time the native and endangered "Peladillas" Aplochiton taeniatus, and the non-native coho salmon, Oncorhynchus kisutch. The coexistence of native and non-native fishes poses a challenge for the management and conservation of aquatic biota from the CHBR. This article is protected by copyright. All rights reserved.

RevDate: 2020-03-18

Liu HB, Rui L, Feng YQ, et al (2020)

Autophagy contributes to resistance to the oxidative stress induced by pine reactive oxygen species metabolism, promoting infection by Bursaphelenchus xylophilus.

Pest management science [Epub ahead of print].

BACKGROUND: Autophagy plays an important role in eukaryotes. We investigated its role in the pine wood nematode (PWN), Bursaphelenchus xylophilus, the causative agent of pine wilt disease (PWD), to find promising control strategies against PWD.

RESULTS: We analysed the expression levels of PtRBOH1 and PtRBOH2, which regulate reactive oxygen species (ROS) metabolism, in Pinus thunbergii and the expression of three autophagy genes, BxATG5, BxATG9, and BxATG16, in PWN by quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and measured the content of H2 O2 , the main product of ROS metabolism, in pine stem. There was a correlation between the expression of autophagy genes in PWN and pine ROS metabolism during early infection. Also, we found that oxidative stress induces autophagy in PWN according to qRT-PCR, transmission electron microscopy, and Western blot analyses. Inhibition of autophagy by 3-methyladenine or silencing of the autophagy genes BxATG9 and BxATG16 in PWN showed that autophagy is essential for the feeding, fecundity, egg hatching, and survival of PWN under oxidative stress, confirming the importance of autophagy in the antioxidant defences of PWN. Similarly, we demonstrated that autophagy contributes to the virulence of PWN. Moreover, PWN likely ameliorates oxidative damage by enhancing the activities of the peroxidase and catalase antioxidant pathways when autophagy is inhibited.

CONCLUSION: Therefore, autophagy contributes to resistance to the oxidative stress induced by pine ROS metabolism, thus promoting infection by PWN. Our findings clarify the defence mechanisms of PWN and the pathogenesis of PWD, and provide promising hints for control of PWD by blocking autophagy. This article is protected by copyright. All rights reserved.

RevDate: 2020-03-18

Heddergott M, Steinbach P, Schwarz S, et al (2020)

Geographic Distribution of Raccoon Roundworm, Baylisascaris procyonis, Germany and Luxembourg.

Emerging infectious diseases, 26(4):821-823.

Infestation with Baylisascaris procyonis, a gastrointestinal nematode of the raccoon, can cause fatal disease in humans. We found that the parasite is widespread in central Germany and can pose a public health risk. The spread of B. procyonis roundworms into nematode-free raccoon populations needs to be monitored.

RevDate: 2020-03-18

Huang Y, Yue ZY, Mao GY, et al (2020)

[Population genetics of invasive Pomacea spp. in Hangzhou City, Zhejiang Province].

Zhongguo xue xi chong bing fang zhi za zhi = Chinese journal of schistosomiasis control, 32(1):23-27.

OBJECTIVE: To investigate the distribution and identify the genetic genetics of invasive Pomacea species in Xihu District, Hangzhou City, so as to understand the spread tendency of Pomacea species.

METHODS: The specimens of Pomacea species were collected from five sites in water systems (lakes, rivers and wetlands) and its costal lands in Xihu District, Hangzhou City in 2017 for morphological identification. Total DNA was isolated from the foot tissues of adult snails for amplification of the COI gene, and haplotype diversity and nucleic acid diversity analyses were performed. In addition, a phylogenetic tree was created based on the haplotype captured from GenBank and those from this study to investigate the phylogenetic relationships.

RESULTS: Pomacea specimens, which were preliminarily characterized as Pomacea, were found in ponds, rivers and wetlands in Xihu District of Hangzhou City. A total of 16 sequences were captured from the DNA samples of Pomacea specimens, which belonged to 3 haplotypes, including Hap1, Hap2 and Hap3. A high frequency was seen in Hap1 and Hap3, and a low frequency was found in Hap2. The Pomacea specimens collected from the 5 sites in Xihu Districts included P. canaliculata and P. maculate. The Pomacea specimens with a Hap1 had a close genetic relationship with the P. canaliculata from Argentina, Guangdong Province and Hong Kong Special Administrative Region of China, and the Pomacea specimens with a Hap2 had a close genetic relationship with the P. canaliculata from Argentina, Japan and Guangzhou City of Guangdong Province, China, while the Pomacea specimens with a Hap2 had a close genetic relationship with the P. maculate from Argentina and Brazil.

CONCLUSIONS: P. canaliculata and P. maculata are present in Xihu District of Hangzhou City. P. maculata may spread to Xihu District through multiple introductions or water flow.

RevDate: 2020-03-18

Cirocco RM, Facelli JM, JR Watling (2020)

The impact of a native hemiparasite on a major invasive shrub is affected by host size at time of infection.

Journal of experimental botany pii:5809316 [Epub ahead of print].

Few studies have examined how parasite impact is affected by host size. In a glasshouse experiment, we investigated the impact of the Australian native hemiparasitic vine, Cassytha pubescens, on a major invasive shrub, Ulex europaeus, of different sizes. Infected plants had significantly lower total, shoot and root biomass, but the parasite's impact was more severe on small than large hosts. When infected small but not large hosts had significantly lower nodule biomass. Irrespective of size, infection significantly decreased host shoot/root ratio, predawn and midday quantum yields, maximum electron transport rates and carbon isotope composition, and host nodule biomass g-1 root biomass significantly increased in response to infection. Infection did not affect host foliar nitrogen concentration or midday shoot water potential. Parasite biomass was significantly lower on small relative to large hosts, but was similar g-1 host total biomass. Parasite stem nitrogen, phosphorous and potassium concentration were significantly greater when C. pubescens was growing on small than large hosts. Our results clearly show that C. pubescens strongly decreases performance of this major invasive shrub, especially when hosts are small. This suggests that C. pubescens could be used most effectively as a native biocontrol when deployed on smaller hosts.

RevDate: 2020-03-18

Kim SH, Kim HB, Cho MS, et al (2020)

Development and characterization of 17 microsatellite markers for Sonchus oleraceus.

Applications in plant sciences, 8(3):e11329 pii:APS311329.

Premise: The common sowthistle, Sonchus oleraceus (Asteraceae), is a globally invasive weedy species. In order to investigate its genetic diversity, population genetic structure, and evolutionary history, we developed and characterized nuclear simple sequence repeat markers (SSRs or microsatellites).

Methods and Results: Seventeen microsatellite primer pairs were developed based on the Illumina sequence data. Ten developed SSR loci were polymorphic in four populations sampled from broad geographical regions. The number of alleles per locus ranged from one to 11, and the levels of observed and expected heterozygosity ranged from 0.000 to 1.000 and from 0.000 to 0.801, respectively. Up to 82% of the newly developed primer pairs were successfully amplified in the congeneric taxa S. asper, S. asper subsp. glaucescens, S. canariensis, and S. palmensis.

Conclusions: The SSR markers developed in this study will be useful for future population genetic studies on S. oleraceus and other congeneric species.

RevDate: 2020-03-18

Lang I, Evangelista C, Everts RM, et al (2020)

Stable resource polymorphism along the benthic littoral-pelagic axis in an invasive crayfish.

Ecology and evolution, 10(5):2650-2660 pii:ECE36095.

Although intraspecific variability is now widely recognized as affecting evolutionary and ecological processes, our knowledge on the importance of intraspecific variability within invasive species is still limited. This is despite the fact that understanding the linkage between within-population morphological divergences and the use of different trophic or spatial resources (i.e., resource polymorphism) can help to better predict their ecological impacts on recipient ecosystems. Here, we quantified the extent of resource polymorphism within populations of a worldwide invasive crayfish species, Procambarus clarkii, in 16 lake populations by comparing their trophic (estimated using stable isotope analyses) and morphological characteristics between individuals from the littoral and pelagic habitats. Our results first demonstrated that crayfish occured in both littoral and pelagic habitats of seven lakes and that the use of pelagic habitat was associated with increased abundance of littoral crayfish. We then found morphological (i.e., body and chelae shapes) and trophic divergence (i.e., reliance on littoral carbon) among individuals from littoral and pelagic habitats, highlighting the existence of resource polymorphism in invasive populations. There was no genetic differentiation between individuals from the two habitats, implying that this resource polymorphism was stable (i.e., high gene flow between individuals). Finally, we demonstrated that a divergent adaptive process was responsible for the morphological divergence in body and chela shapes between habitats while difference in littoral reliance neutrally evolved under genetic drift. These findings demonstrated that invasive P. clarkii can display strong within-population phenotypic variability in recent populations, and this could lead to contrasting ecological impacts between littoral and pelagic individuals.

RevDate: 2020-03-18

Rey A, Basurko OC, N Rodriguez-Ezpeleta (2020)

Considerations for metabarcoding-based port biological baseline surveys aimed at marine nonindigenous species monitoring and risk assessments.

Ecology and evolution, 10(5):2452-2465 pii:ECE36071.

Monitoring introduction and spread of nonindigenous species via maritime transport and performing risk assessments require port biological baseline surveys. Yet, the comprehensiveness of these surveys is often compromised by the large number of habitats present in a port, the seasonal variability, and the time-consuming morphological approach used for taxonomic identification. Metabarcoding represents a promising alternative for rapid comprehensive port biological baseline surveys, but its application in this context requires further assessments.We applied metabarcoding (based on barcodes of the cytochrome c oxidase subunit I and of the 18S ribosomal RNA gene) to 192 port samples collected (a) from diverse habitats (water column-including environmental DNA and zooplankton, sediment, and fouling structures), (b) at different sites (from inner to outer estuary), and iii) during the four seasons of the year.By comparing the biodiversity metrics derived from each sample group, we show that each sampling method resulted in a distinct community profile and that environmental DNA alone cannot substitute for organismal sampling, and that, although sampling at different seasons and locations resulted in higher observed biodiversity, operational results can be obtained by sampling selected locations and seasons.By assessing the taxonomic composition of the samples, we show that metabarcoding data allowed the detection of previously recorded nonindigenous species as well as to reveal presence of new ones, even if in low abundance. Synthesis and application. Our comprehensive assessment of metabarcoding for port biological baseline surveys sets the basics for cost-effective, standardized, and comprehensive monitoring of nonindigenous species and for performing risk assessments in ports. This development will contribute to the implementation of the recently entered into force International Convention for the Control and Management of Ships' Ballast Water and Sediments.

RevDate: 2020-03-18

Shan T, Yuan J, Su L, et al (2020)

First Genome of the Brown Alga Undaria pinnatifida: Chromosome-Level Assembly Using PacBio and Hi-C Technologies.

Frontiers in genetics, 11:140.

RevDate: 2020-03-18

Pace A, Dipineto L, Aceto S, et al (2020)

Diagnosis of Centrocestus formosanus Infection in Zebrafish (Danio rerio) in Italy: A Window to a New Globalization-Derived Invasive Microorganism.

Animals : an open access journal from MDPI, 10(3): pii:ani10030456.

:Centrocestus formosanus is a digenetic trematode with a complex life cycle, involving invertebrate and vertebrate hosts, humans included. In particular, it causes gill lesions and mortality in freshwater fish species, and gastrointestinal symptoms in infected humans. Here, we describe the occurrence of C. formosanus infection in zebrafish imported in Italy and propose a newly designed species-specific primer pair to ameliorate the diagnostic investigations for C. formosanus. Gill arches of 30 zebrafish were examined for the presence of encysted metacercariae under a stereomicroscope and processed through molecular analyses targeting the ribosomal internal transcribed sequence 2 (ITS2). Although C. formosanus distribution was originally restricted to Asia, it has been subsequently reported in new countries, revealing itself as an invasive species and raising important concerns for biodiversity, economy, scientific research, as well as animal and public health. Given the crucial role played by the ornamental fish industry in spreading this parasite, there is an urgent need for control measures to prevent the introduction and establishment of C. formosanus in non-endemic areas, including Europe. We also suggest developing new strategies in microbiology and epidemiology to better explore this new globalization-derived invasive species.

RevDate: 2020-03-18
CmpDate: 2020-03-18

Friebertshauser R, Shollenberger K, Janosik A, et al (2019)

The effect of bivalve filtration on eDNA-based detection of aquatic organisms.

PloS one, 14(11):e0222830.

As the use of environmental-DNA (eDNA) expands as a method to detect the presence and quantity of aquatic taxa, factors potentially impacting the efficacy of this technique must be investigated. Many studies have examined the effects of abiotic parameters on the degradation of environmental-DNA (e.g. UV radiation, pH, temperature, etc.), however, few have focused on biotic effectors. Through high-filtering rates coupled with dense colonization, Asian clams (Corbicula fluminea) are able to drastically alter the quantity of particulate matter through translocation into the sediment, potentially including sources of eDNA in lotic and lentic systems. Using a longitudinal, laboratory experiment, we tested the effect of varying densities of Asian clams on the translocation rate of common goldfish (Carassius auratus) DNA. Target DNA in testing tanks was quantified through quantitative PCR (qPCR) at regular intervals and compared. Tanks housing the highest density of Asian clams produced significantly lower DNA concentrations over time compared to tanks of lower densities. These results show, for the first time, a density-dependent reduction of local eDNA sources by bivalve filtration that may lead to the obstructed detection of target species through the sampling of eDNA. Based on these findings, we recommend highly concentrated bivalve populations be taken into consideration when choosing the time and locality of eDNA sampling efforts.

RevDate: 2020-03-18
CmpDate: 2020-03-18

Bachtel RZ, Rittenhouse M, Sandland GJ, et al (2019)

Infection patterns of trematodes across size classes of an invasive snail species using field and laboratory studies.

Parasitology, 146(4):438-444.

In the Upper Mississippi River Region, invasive faucet snails (Bithynia tentaculata) and their trematode parasites have been implicated in more than 182 000 waterfowl deaths since 1996. Estimating transmission potential depends on accurate assessments of susceptible host population size. However, little is known about the mechanisms underlying snail-host susceptibility in this system. Prior field studies suggest that very small, likely young, faucet snails are less suitable secondary intermediate hosts. Here, we test whether the patterns observed in the field are because small snails (1) are refractory to infection by cercariae, (2) die from infection and are removed from sampled populations, and/or (3) are not preferred by cercariae. Our own field collections were consistent with the observation that smaller faucet snails exhibit lower metacercarial infection prevalence and abundance than larger snails. However, laboratory-based experiments show that smaller snails were actually more susceptible to infection than larger snails. Moreover, the smallest snail size class had significantly higher mortality than larger snails following infection, which may explain their reduced infection levels observed in the field. Our study demonstrates the importance of pairing field and laboratory studies to better understand mechanisms underlying patterns of infection.

RevDate: 2020-03-17

Liffner B, Frölich S, Heinemann GK, et al (2020)

PfCERLI1 is a conserved rhoptry associated protein essential for Plasmodium falciparum merozoite invasion of erythrocytes.

Nature communications, 11(1):1411 pii:10.1038/s41467-020-15127-w.

The disease-causing blood-stage of the Plasmodium falciparum lifecycle begins with invasion of human erythrocytes by merozoites. Many vaccine candidates with key roles in binding to the erythrocyte surface and entry are secreted from the large bulb-like rhoptry organelles at the apical tip of the merozoite. Here we identify an essential role for the conserved protein P. falciparum Cytosolically Exposed Rhoptry Leaflet Interacting protein 1 (PfCERLI1) in rhoptry function. We show that PfCERLI1 localises to the cytosolic face of the rhoptry bulb membrane and knockdown of PfCERLI1 inhibits merozoite invasion. While schizogony and merozoite organelle biogenesis appear normal, biochemical techniques and semi-quantitative super-resolution microscopy show that PfCERLI1 knockdown prevents secretion of key rhoptry antigens that coordinate merozoite invasion. PfCERLI1 is a rhoptry associated protein identified to have a direct role in function of this essential merozoite invasion organelle, which has broader implications for understanding apicomplexan invasion biology.

RevDate: 2020-03-16

Harron P, Joshi O, Edgar CB, et al (2020)

Predicting Kudzu (Pueraria montana) spread and its economic impacts in timber industry: A case study from Oklahoma.

PloS one, 15(3):e0229835 pii:PONE-D-19-22727.

Quantifying the economic impacts of invasive species is an essential step in developing and prioritizing invasive species management. In particular, kudzu, Pueraria montana (Lour.) Merr. is an aggressive and non-native vine that not only causes ecological damage and reduces biodiversity, but can have multiple economic consequences such as loss of timber value and volume. Using current infestation locations in Oklahoma, southcentral USA, a Monte Carlo simulation was run to estimate the natural as well as anthropogenic spread rate of kudzu in the next five years. Simulations were supplemented with an economic impact analysis within the Impact Analysis for PLANing (IMPLAN) platform. To account for economic loss in the forest product industry, a replacement cost approach with a sensitivity analysis was conducted. Occurrence data collections revealed that current kudzu populations are already established in Oklahoma forests. The results demonstrate that by year five, total industry output could be reduced by $167.9 million, which will influence 780 jobs in the most extreme case scenario. The predicted economic loss due to kudzu expansion could act as an incentive for appropriate management practices and plans to be implemented.

RevDate: 2020-03-16

Ge B, Jiang S, Yang L, et al (2020)

Succession of macrofaunal communities and environmental properties along a gradient of smooth cordgrass Spartina alterniflora invasion stages.

Marine environmental research, 156:104862.

The exotic species smooth cordgrass (Spartina alterniflora) is recognized as an important invasive species in China, introduced about 40 years ago. The consistent smooth cordgrass invasion significantly modified the coastal ecosystem. Understanding the ecological succession and mechanisms of wetland soil ecosystems is essential for biological conservation after the landscape change resulting from the smooth cordgrass invasion. In this study, five different invasion stages of a 16-year smooth cordgrass invasion sequence were identified in a coastal wetland as no invasion, initial invasion, young invasion, mature invasion, and senescing invasion. The succession of macrofaunal communities and environments were investigated along the gradient of invasion stages. The infauna decreased, and the epifauna increased along the invasion sequence. The significant differences of the communities were detected among the mud flats experiencing different invasion stages. The initial and young invasion stages of smooth cordgrass possibly promote the macrofaunal biodiversity, but biodiversity decreased at mature and senescing invasion stages. The ecological effect of smooth cordgrass invasion on macrofauna depended on the species' traits and the invasion stage. The environmental properties co-varied with invasion stages, and varied significantly among selected habitats. Total organic carbon (TOC), total nitrogen, and the carbon-nitrogen ratio (C/N) strongly related to the smooth cordgrass coverage, stem density, and height. C/N was identified as the key factor for shaping the environment by principal components analysis, and TOC for regulating the macrofaunal community by canonical correspondence analysis. The succession of macrofaunal communities should be considered as a comprehensive response to the variations on environmental properties co-varying with smooth cordgrass invasion in coastal wetlands.

RevDate: 2020-03-16

Puckett EE, Orton D, J Munshi-South (2020)

Commensal Rats and Humans: Integrating Rodent Phylogeography and Zooarchaeology to Highlight Connections between Human Societies.

BioEssays : news and reviews in molecular, cellular and developmental biology [Epub ahead of print].

Phylogeography and zooarchaeology are largely separate disciplines, yet each interrogates relationships between humans and commensal species. Knowledge gained about human history from studies of four commensal rats (Rattus rattus, R. tanezumi, R. exulans, and R. norvegicus) is outlined, and open questions about their spread alongside humans are identified. Limitations of phylogeographic and zooarchaeological studies are highlighted, then how integration would increase understanding of species' demographic histories and resultant inferences about human societies is discussed. How rat expansions have informed the understanding of human migration, urban settlements, trade networks, and intra- and interspecific competition is reviewed. Since each rat species is associated with different human societies, they identify unique ecological and historical/cultural conditions that influenced their expansion. Finally, priority research areas including nuclear genome based phylogeographies are identified using archaeological evidence to understand R. norvegicus expansion across China, multi-wave colonization of R. rattus across Europe, and competition between R. rattus and R. norvegicus.

RevDate: 2020-03-16

Zink FA, Tembrock LR, Timm AE, et al (2020)

A Real-Time PCR Assay for Rapid Identification of Tuta absoluta (Lepidoptera: Gelechiidae).

Journal of economic entomology pii:5805490 [Epub ahead of print].

The tomato leafminer, Tuta absoluta (Meyrick), is a highly destructive pest of tomatoes, causing damage to leaves, stalks, buds, and fruits. Native to South America, T. absoluta is now found throughout Europe, South Asia, Africa, parts of Central America, and the Caribbean. Adults are small, with a wingspan of approximately one cm and lack distinctive markings, making morphological identification difficult. Larvae are also difficult to identify and resemble those of many other gelechiids. Due to the extensive time spent and expertise required for morphological identification, and the imminent threat to the North American tomato crop, we have developed a rapid molecular test for discriminating individual specimens of T. absoluta using a probe-based real-time polymerase chain reaction (PCR) assay. The assay is able to quickly distinguish T. absoluta from similar-sized moth specimens that are attracted to T. absoluta pheromone lures in the United States and is also able to identify larvae of T. absoluta. Decreased identification time for this critical pest will lead to more rapid identification at ports of entry and allow for more efficient trap screening for domestic monitoring programs.

RevDate: 2020-03-16

Banerjee AK, Hou Z, Lin Y, et al (2020)

Going with the flow: analysis of population structure revealed high gene flow shaping invasion pattern and inducing range expansion of Mikania micrantha in Asia.

Annals of botany pii:5805509 [Epub ahead of print].

BACKGROUND AND AIMS: Mikania micrantha Kunth, a climbing perennial weed of the family Asteraceae, is native to Latin America and is highly invasive in the tropical belt of Asia, Oceania and Australia. This study was framed to investigate the population structure of M. micrantha at a large spatial scale in Asia and to identify how introduction history, evolutionary forces and landscape features influenced the genetic pattern of the species in this region.

METHODS: We assessed the genetic diversity and structure of 1052 individuals from 46 populations for 12 microsatellite loci. The spatial pattern of genetic variation was investigated by estimating the relationship between genetic distance and geographic, climatic and landscape resistances hypothesized to influence gene flow between populations.

KEY RESULTS: We found high genetic diversity of M. micrantha in this region, as compared with the genetic diversity parameters of other invasive species. The spatial and non-spatial clustering algorithms identified the presence of multiple genetic clusters and admixture between populations. Most of the populations showed heterozygote deficiency, primarily due to inbreeding, and the founder populations showed evidence of a genetic bottleneck. Persistent gene flow throughout the invasive range caused low genetic differentiation among populations and provided beneficial genetic variation to the marginal populations in a heterogeneous environment. Environmental suitability was found to buffer the detrimental effects of inbreeding at the leading edge of range expansion. Both linear and nonlinear regression models demonstrated a weak relationship between genetic distance and geographic distance, as well as bioclimatic variables and environmental resistance surfaces.

CONCLUSIONS: These findings provided evidence that extensive gene flow and admixture between populations influences the current genetic pattern of M. micrantha in this region. High gene flow across the invaded landscape may facilitate adaptation, establishment and long-term persistence of the population, thereby indicating the range expansion ability of the species.

RevDate: 2020-03-15

Sparks ME, Bansal R, Benoit JB, et al (2020)

Brown marmorated stink bug, Halyomorpha halys (Stål), genome: putative underpinnings of polyphagy, insecticide resistance potential and biology of a top worldwide pest.

BMC genomics, 21(1):227 pii:10.1186/s12864-020-6510-7.

BACKGROUND: Halyomorpha halys (Stål), the brown marmorated stink bug, is a highly invasive insect species due in part to its exceptionally high levels of polyphagy. This species is also a nuisance due to overwintering in human-made structures. It has caused significant agricultural losses in recent years along the Atlantic seaboard of North America and in continental Europe. Genomic resources will assist with determining the molecular basis for this species' feeding and habitat traits, defining potential targets for pest management strategies.

RESULTS: Analysis of the 1.15-Gb draft genome assembly has identified a wide variety of genetic elements underpinning the biological characteristics of this formidable pest species, encompassing the roles of sensory functions, digestion, immunity, detoxification and development, all of which likely support H. halys' capacity for invasiveness. Many of the genes identified herein have potential for biomolecular pesticide applications.

CONCLUSIONS: Availability of the H. halys genome sequence will be useful for the development of environmentally friendly biomolecular pesticides to be applied in concert with more traditional, synthetic chemical-based controls.

RevDate: 2020-03-17
CmpDate: 2020-03-17

Ray D, Behera MD, J Jacob (2020)

Comparing invasiveness of native and non-native species under changing climate in North-East India: ecological niche modelling with plant types differing in biogeographic origin.

Environmental monitoring and assessment, 191(Suppl 3):793.

We assess the invasive potential of Ageratum conyzoides, Hevea brasiliensis, Urena lobata and Imperata cylindrica differing in habit and biogeographic origin through ecological niche modelling in the context of the 2000 and 2050 climates of North-East (NE) India. Out of these four species, Ageratum conyzoides, Urena lobata and Imperata cylindrica are naturally occurring weed species and Hevea brasiliensis is a cultivated tree species. This study tries to address a basic question whether species with similarity in biogeographic origin may have some uniform strategy to succeed in invasion process. Ecological niche models predicted that Ageratum conyzoides (a shrub) and Hevea brasiliensis (a tree) of South American origin have greater potential to invade/distribute in NE region of India by 2050 than two other species, Urena lobata and Imperata cylindrica, of South-Asian origin. The latter two species show lower potential to invade in NE India in 2050 compared with their extent of distribution in 2000. A set of major contributing bioclimatic factors responsible for distribution of two South-Asian species (Urena and Imperata sp.) remain more or less constant between 2000 and 2050 climates. However, the distribution of Ageratum sp. and Hevea sp. with respect to two climate scenarios is attributed by two different sets of major bioclimatic factors. This indicates the robustness of the species to get adapted to different set of climatic variables over time.

RevDate: 2020-03-17
CmpDate: 2020-03-17

Ahmad R, Khuroo AA, Hamid M, et al (2020)

Plant invasion alters the physico-chemical dynamics of soil system: insights from invasive Leucanthemum vulgare in the Indian Himalaya.

Environmental monitoring and assessment, 191(Suppl 3):792.

Understanding the impact of plant invasions on the terrestrial ecosystems, particularly below-ground soil system dynamics can be vital for successful management and restoration of invaded landscapes. Here, we report the impacts of a global plant invader, Leucanthemum vulgare Lam. (ox-eye daisy), on the key physico-chemical soil properties across four sites selected along an altitudinal gradient (1600-2550 m) in Kashmir Himalaya, India. At each site, two types of spatially separated but environmentally similar sampling plots: invaded (IN) and uninvaded (UN) were selected for soil sampling. The results revealed that invasion by L. vulgare had a significant impact on key soil properties in the IN plots. The soil pH, water content, organic carbon and total nitrogen were significantly higher in the IN plots as compared with the UN plots. In contrast, the electrical conductivity, phosphorous and micronutrients, viz. iron, copper, manganese and zinc, were significantly lower in the IN plots as compared with the UN plots. These changes in the soil system dynamics associated with L. vulgare invasion were consistent across all the sites. Also, among the sites, soil properties of low-altitude site (1600 m) were different from the rest of the sampling sites. Overall, the results of the present study indicate that L. vulgare, by altering key properties of the soil system, is likely to influence nutrient cycling processes and facilitates positive feedback for itself. Furthermore, the research insights from this study have wide management implications in the effective ecological restoration of the invaded landscapes.

RevDate: 2020-03-17
CmpDate: 2020-03-17

Causton CE, Moon RD, Cimadom A, et al (2019)

Population dynamics of an invasive bird parasite, Philornis downsi (Diptera: Muscidae), in the Galapagos Islands.

PloS one, 14(10):e0224125.

The invasive parasitic fly, Philornis downsi (Muscidae), is one of the greatest threats to the avifauna of the Galapagos Islands. The larvae of this fly feed on the blood and tissues of developing nestlings of at least 18 endemic and native birds. The aim of the current study was to investigate biotic and abiotic factors that may influence the population dynamics of this invasive parasite. To study the influence of vegetation zone and related climatic factors on fly numbers, a bi-weekly monitoring program using papaya-baited traps was carried out at a dry, lowland site and at a humid, highland site on Santa Cruz Island between 2012-2014. Female flies, a large proportion of which were inseminated and gravid, were collected throughout the year at both sites, indicating females were active during and between the bird breeding seasons. This is the first evidence that female flies are able to persist even when hosts are scarce. On the other hand, catch rates of male flies declined between bird breeding seasons. Overall, catch rates of P. downsi were higher in the drier, lowland habitat, which may be a consequence of host or resource availability. Time was a stronger predictor of adult fly numbers than climate, further suggesting that P. downsi does not appear to be limited by its environment, but rather by host availability. Seasonal catch rates suggested that populations in both habitats were continuous and multivoltine. Numbers of adult female flies appeared to be regulated chiefly by simple direct density dependence, and may be governed by availability of bird nests with nestlings. Nevertheless, confounding factors such as the existence of reservoir hosts that perpetuate fly populations and changes in behavior of P. downsi may increase the vulnerability of bird hosts that are already IUCN red-listed or in decline.

RevDate: 2020-03-16
CmpDate: 2020-03-16

Solórzano-Alava L, Sánchez-Amador F, T Valverde (2019)

Angiostrongylus (Parastrongylus) cantonensis on intermediate and definitive hosts in Ecuador, 2014-2017.

Biomedica : revista del Instituto Nacional de Salud, 39(2):370-384.

RevDate: 2020-03-16
CmpDate: 2020-03-16

Tippelt L, Werner D, H Kampen (2019)

Tolerance of three Aedes albopictus strains (Diptera: Culicidae) from different geographical origins towards winter temperatures under field conditions in northern Germany.

PloS one, 14(7):e0219553.

The continuing spread of the Asian tiger mosquito Aedes albopictus, a vector of many arboviruses and some dirofilarial worms, in Europe calls for advanced investigations on its ecological ability to establish and overwinter in temperate, more northern geographic regions. To meet this purpose, eggs of Ae. albopictus laboratory strains of tropical, subtropical and temperate origin were exposed to field conditions during one or two winter seasons in northeastern Germany. After 1 to 16 weeks of outdoor exposure, eggs were flooded in the laboratory, and the hatching rates were determined. During the winter season 2015/2016, when temperatures reached -10°C, the subtropical strain showed hatching after all time periods while the tropical strain displayed hatching only until two weeks of cold exposure. In the winter season 2016/2017, with temperatures as low as ‒6°C, all three strains produced hatching larvae after all time periods. Both the hatching rates and the hatching behaviour differed between the strains. Larvae of the subtropical and temperate strains hatched in installments over a period of four weeks while the larvae of the tropical strain hatched within a short time period, often one week. The results of the study demonstrate that Ae. albopictus strains of different, even tropical, origin might be able to survive a central European winter, although this is likely to depend on the specific course of the temperatures. Further studies with different temperature regimes and different mosquito strains are needed to specify these findings.


ESP Quick Facts

ESP Origins

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.

ESP Support

In 1995, Robbins became the VP/IT of the Fred Hutchinson Cancer Research Center in Seattle, WA. Soon after arriving in Seattle, Robbins secured funding, through the ELSI component of the US Human Genome Project, to create the original ESP.ORG web site, with the formal goal of providing free, world-wide access to the literature of classical genetics.

ESP Rationale

Although the methods of molecular biology can seem almost magical to the uninitiated, the original techniques of classical genetics are readily appreciated by one and all: cross individuals that differ in some inherited trait, collect all of the progeny, score their attributes, and propose mechanisms to explain the patterns of inheritance observed.

ESP Goal

In reading the early works of classical genetics, one is drawn, almost inexorably, into ever more complex models, until molecular explanations begin to seem both necessary and natural. At that point, the tools for understanding genome research are at hand. Assisting readers reach this point was the original goal of The Electronic Scholarly Publishing Project.

ESP Usage

Usage of the site grew rapidly and has remained high. Faculty began to use the site for their assigned readings. Other on-line publishers, ranging from The New York Times to Nature referenced ESP materials in their own publications. Nobel laureates (e.g., Joshua Lederberg) regularly used the site and even wrote to suggest changes and improvements.

ESP Content

When the site began, no journals were making their early content available in digital format. As a result, ESP was obliged to digitize classic literature before it could be made available. For many important papers — such as Mendel's original paper or the first genetic map — ESP had to produce entirely new typeset versions of the works, if they were to be available in a high-quality format.

ESP Help

Early support from the DOE component of the Human Genome Project was critically important for getting the ESP project on a firm foundation. Since that funding ended (nearly 20 years ago), the project has been operated as a purely volunteer effort. Anyone wishing to assist in these efforts should send an email to Robbins.

ESP Plans

With the development of methods for adding typeset side notes to PDF files, the ESP project now plans to add annotated versions of some classical papers to its holdings. We also plan to add new reference and pedagogical material. We have already started providing regularly updated, comprehensive bibliographies to the ESP.ORG site.


Order from Amazon

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

Electronic Scholarly Publishing
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Bellingham, WA 98226

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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).


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


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.

ESP Picks from Around the Web (updated 07 JUL 2018 )