The nutria (Myocastor coypus) was introduced to South Korea in 1987 for breeding of individuals for fur and meat industry, and was accidentally released into the wild. Here, we report the development ...of microsatellites for the nutria collected from South Korea using Illumina MiSeq genome sequencing to identify the genetic variability and demographic history of these introduced populations. A total of 626,282 microsatellite sequences were identified, and nine polymorphic loci were characterized. We used four novel loci developed and three previously known loci to investigate the genetic diversity of twelve South Korean populations. A low level of diversity was found, and no signature of genetic structuring was revealed among populations, indicating that Korean nutria individuals originated from a single population or a highly inbred reared herd.
The vomiting (emetic) reflex is documented in numerous mammalian species, including primates and carnivores, yet laboratory rats and mice appear to lack this response. It is unclear whether these ...rodents do not vomit because of anatomical constraints (e.g., a relatively long abdominal esophagus) or lack of key neural circuits. Moreover, it is unknown whether laboratory rodents are representative of Rodentia with regards to this reflex. Here we conducted behavioral testing of members of all three major groups of Rodentia; mouse-related (rat, mouse, vole, beaver), Ctenohystrica (guinea pig, nutria), and squirrel-related (mountain beaver) species. Prototypical emetic agents, apomorphine (sc), veratrine (sc), and copper sulfate (ig), failed to produce either retching or vomiting in these species (although other behavioral effects, e.g., locomotion, were noted). These rodents also had anatomical constraints, which could limit the efficiency of vomiting should it be attempted, including reduced muscularity of the diaphragm and stomach geometry that is not well structured for moving contents towards the esophagus compared to species that can vomit (cat, ferret, and musk shrew). Lastly, an in situ brainstem preparation was used to make sensitive measures of mouth, esophagus, and shoulder muscular movements, and phrenic nerve activity–key features of emetic episodes. Laboratory mice and rats failed to display any of the common coordinated actions of these indices after typical emetic stimulation (resiniferatoxin and vagal afferent stimulation) compared to musk shrews. Overall the results suggest that the inability to vomit is a general property of Rodentia and that an absent brainstem neurological component is the most likely cause. The implications of these findings for the utility of rodents as models in the area of emesis research are discussed.
The role of large frugivores in the dispersal of tropical trees has been well‐studied, whereas the importance of the world's largest rodents for plant dispersal has previously been ignored. We ...studied plant dispersal by gut passage (endozoochory) in Neotropical wetlands by the largest extant rodent, the capybara Hydrochoerus hydrochaeris. We compared it with another of the world's 10 largest rodents, the nutria or coypu Myocastor coypus.
We collected 96 faecal samples (50 capybara, 46 nutria) from 10 sites within the Taim Ramsar site in southern Brazil, and extracted intact propagules from 10 g subsamples. Propagules from 27 plant taxa (24 angiosperms, and three aquatic ferns) were recovered, representing 13 plant families. Whole Spirodela (duckweed) plants were dispersed. Seeds from 14 angiosperm taxa were germinated in the laboratory.
Taxonomic composition of propagules was significantly different for the two mammals, but propagule size was not. Capybara dispersed more terrestrial propagules per sample, and nutrias more aquatic propagules. When total faecal production was taken into account, an estimated 1025 propagules (including 133 fern spores) were dispersed by each capybara per day, compared with 691 propagules for nutrias (including 566 fern spores). Capybaras have larger home ranges and likely dispersed plants over a greater distance.
Synthesis: This is the first demonstration that rodents disperse aquatic pteridophytes as well as flowering plants. Our results suggest that capybaras and nutrias play important, complementary roles in dispersing a variety of aquatic and terrestrial plant species within Neotropical wetlands. Our study indicates that the role of herbivorous mammals as vectors of plants with small seeds and non‐fleshy fruits has been overlooked in the neotropics and that defaunation of large herbivores can have negative consequences, in a manner similar to that previously highlighted for frugivores.
Resumo
O papel dos grandes frugívoros na dispersão de árvores tropicais tem sido bem estudado, entretanto, a importância dos maiores roedores do mundo na dispersão de plantas tem sido previamente ignorada. Estudamos a dispersão de plantas que passaram pelo sistema digestivo (endozoocoria) do maior roedor do mundo, a capivara Hydrochoerus hydrochaeris, em áreas úmidas Neotropicais. Além disso, comparamos os resultados com outro mamífero que está entre os 10 maiores roedores do mundo, o ratão‐do‐banhado Myocastor coypus.
Para realizar esta pesquisa, coletamos 96 amostras fecais (50 de capivaras e 46 de ratão‐do‐banhado) em 10 locais distintos na Estação Ecológica do Taim, um sítio Ramsar no sul do Brasil. Posteriormente, extraímos os propágulos intactos de subamostras de 10 g. Propágulos de 27 táxons de plantas (24 angiospermas e três pteridófitas aquáticas) foram recuperados, representando 13 famílias de plantas. Encontramos plantas inteiras do gênero Spirodela (lentilha d'água) sendo dispersas. Sementes de 14 táxons de angiospermas foram germinadas em laboratório.
A composição taxonômica dos propágulos foi significativamente diferente entre os dois mamíferos, mas o tamanho dos propágulos não. Capivaras dispersaram mais propágulos de plantas terrestres por amostra, enquanto ratões‐do‐banhado dispersaram mais propágulos de plantas aquáticas. Quando a produção fecal total foi levada em conta, estimou‐se que cada capivara dispersa 1025 propágulos (incluindo 133 esporos de pteridófitas) por dia, comparado com 691 propágulos dispersos pelos ratões‐do‐banhado (incluindo 566 esporos de pteridófitas). As capivaras têm áreas de vida maiores e provavelmente dispersam plantas por distâncias maiores.
Síntese Esta é a primeira demonstração de que roedores dispersam pteridófitas aquáticas, bem como angiospermas. Nossos resultados sugerem que capivaras e ratões‐do‐banhado desempenham papéis importantes e complementares na dispersão de uma variedade de espécies de plantas aquáticas e terrestres em áreas úmidas Neotropicais. Nosso estudo indica que o papel dos mamíferos herbívoros como vetores de plantas com sementes pequenas e frutos não carnosos tem sido negligenciado na região neotropical, e que a defaunação de grandes herbívoros pode ter consequências negativas, de maneira semelhante ao que foi anteriormente destacado para frugívoros.
This study is the first to show that the world's largest rodents can disperse both aquatic pteridophytes and flowering plants. Capybaras and nutrias play complementary roles in Neotropical wetlands, dispersing a variety of aquatic and terrestrial plant species. The research underscores the overlooked role of herbivorous mammals as dispersers of small‐seeded plants in the Neotropics and warns that the defaunation of these herbivores can lead to significant ecological consequences.
Nutria (
Myocastor coypus
) were introduced to the eastern shore of Chesapeake Bay, USA in the 1940s. They reached peak densities in the late 1990s, causing massive wetland loss. Beginning in 2002, a ...systematic plan to eradicate nutria from the 1.7M ha Delmarva Peninsula was implemented. Since that time the nutria population has been effectively reduced, and no nutria have been detected since May 2015. A lack of detection does not equate with complete absence. We address the following three questions. (1) What is the expected probability of nutria eradication from the Delmarva Peninsula as of the end of 2020? (2) If the probability of eradication is below the management target of 0.95, how much more surveillance is required? (3) How sensitive is the estimated probability of eradication to varying levels of public surveillance and modelled population growth rates? These questions were addressed by employing a stochastic spatially-explicit surveillance model that uses data in which no nutria were detected to quantify the probability of complete absence (
PoA
) over the entire Delmarva Peninsula. We applied an analytical framework that decomposes the spatial risk of survivors and data into management zones, and took advantage of low-cost public reporting of nutria sightings. Active surveillance by the eradication program included detector dog and tracker surveys, shoreline surveys, detection with ground and water platforms (with hair snares), and camera traps. Results showed that the
PoA
increased with time and surveillance from a beginning
PoA
in May 2015 of 0.01 to a mean of 0.75 at the end of 2020. This indicates that the
PoA
on the Delmarva was well below the target threshold of 0.95 for declaring eradication success. However, given continued surveillance without detection, a
PoA
of 0.95 would be achieved by June 2022. This analysis provides an objective mechanism to align the expectations of policy makers, managers and the public on when eradication of nutria from the entire Delmarva Peninsula should be declared successful.
Nutria,
Myocastor coypus
, native to South America, is one of the world's worst invasive mammals, having major ecological and economic consequences. We evaluated the realized climatic niches of ...nutria in their native and invasive regions (Africa, Asia, Europe, and North America) to investigate whether niche changes occurred during their invasion, as well as to assess the extent of niche conservatism and environmental equilibrium. We also explored current and future potential distributions of nutria under climate change. Based on niche equivalence and similarity tests, niches with moderate to high overlap were conserved in Western Asia, Europe, and North America, whereas niches with zero to low overlap in East Asia and Africa were shifted. Nutria showed high niche stability and low niche expansion across Africa, Europe, and North America. The high level of unfilled niches suggests great potential for further expansion into East Asia, Europe, and Africa. Asia, on the other hand, has shown the greatest niche occupancy in non-native ranges. In 2070, nutria habitat conditions were predicted to expand in Western Asia, Europe, and North America towards higher latitudes, while their southern ranges contracted. Also, ensemble models indicate that areas in Southern Australia and Oceania where nutria are not known to occur are well suited for their colonization. The results of this study provide valuable insight into the nutria's niche dynamics as well as its current and future distribution status on a global scale, suggesting that it may adapt to a wide range of environments.
Platforms are structures built by coypus for various purposes, such as reproduction, resting, and thermoregulation. In a coastal wetland of central Italy, during a study aimed at investigating the ...characteristics of coypu’s platforms, it was recorded, for the first time worldwide, the presence of plastic in these structures. Through a transect survey, we censused 83 platforms, among which three (3.61%) were found with presence of macro- and megaplastics (polystyrene, polypropylene, and low-density polyethylene in film form; polyester, polyamide, and expanded polystyrene in fragments). Through the FTIR spectra, it was possible to highlight the degradation of the polymeric materials. To stimulate possible in-depth investigations at the level of the food chain (e.g., coypu predators, including canids) in wet habitats, we discussed possible causes and implications of plastic presence in coypus’ nest structures.
is a major gastrointestinal parasite found globally in both humans and animals. This work examined the occurrence of
in coypus (
) in China. Multi-locus analysis was conducted to evaluate the level ...of genetic variation and the potential zoonotic role of the isolates. In total, 308 fecal samples were collected from seven farms in China and subjected to PCR screening to reveal
. Notably,
was detected in 38 (12.3%) specimens from assemblages A (
= 2) and B (
= 36). Positive samples were further characterized by PCR and nucleotide sequencing of the triose phosphate isomerase (
), beta giardin (
), and glutamate dehydrogenase (
) genes. Multi-locus genotyping yielded 10 novel multi-locus genotypes (MLGs) (one MLG and nine MLGs for assemblages A and B, respectively). Based on the generated phylogenetic tree, AI-novel 1 clustered more closely with MLG AI-2. Furthermore, within the assemblage B phylogenetic analysis, the novel assemblage B MLGs were identified as BIV and clustered in the MLG BIV branch. This is the first report of
in coypus in China. The presence of zoonotic genotypes and subtypes of
in coypus suggests that these animals can transmit human giardiasis.
Taguatagua 1 is a late Pleistocene open-air archaeological site located on an ancient lakeshore in central Chile and dated to around 12,600 cal BP. It presents clear evidence of human and megafauna ...(Equidae, Gomphotheriidae and Cervidae) interaction that includes burned, fractured and cut-marked bones, as well as tusk and bone-made instruments. Mixed with artefacts and megafauna bones, an outstanding small vertebrate record (Class Actinopterygii, Amphibia, Reptilia, Aves and Mammalia) has also been reported, which has remained largely unstudied. In this paper, we present the first comprehensive taphonomic study of a selected sample of this ensemble. Birds are the most common taxa, followed by anurans, fish and rodents. Surface modifications, bone breakage, skeletal frequencies and the sample's ecological/biological attributes indicate different taphonomic trajectories for an averaged sample. A portion of the ensemble entered the context via predators and natural deaths, but the presence of anthropogenic marks, especially in aquatic birds, and to a lesser extent in Myocastor coypus and Calyptocephalella sp., indicates cultural exploitation of these taxa. These results portray a more precise image of the late Pleistocene hunter-gatherer subsistence strategies in central Chile, which is consistent with the settlement's lacustrine context.
•Taguatagua 1 shows evidence of human consumption of small game, especially waterfowl.•Fish and anurans entered to the archaeological deposit mainly via natural deaths.•Small caviomorphs were mainly predated, but the large ones were culturally exploited.•Taxonomic richness indices suggest a high specialisation in small fauna exploitation.
Nutria, or coypu (Myocastor coypus), are invasive semi‐aquatic rodents present across the United States, Europe, and Asia. Despite successful eradication efforts in certain areas, nutria have ...resurged in the mid‐Atlantic USA, underscoring the need for advanced monitoring tools. Environmental DNA (eDNA) has emerged as a promising technique for species detection and monitoring. Here, an eDNA assay for nutria using qPCR was field‐validated in Virginia, USA, showcasing its potential as a tool for post‐eradication monitoring. The findings reveal an association between water levels and detection of nutria eDNA, highlighting the importance of water levels in nutria behavior. A painted turtle assay was introduced to confirm nutria absence and demonstrate the potential of passive sampling. The study showcases the sensitivity and efficiency of eDNA assays, emphasizing their value for monitoring and verifying invasive species eradication.
An eDNA assay for nutria was field‐validated in Virginia, USA, showcasing its potential as a tool for post‐eradication monitoring. The findings reveal an association between water levels and nutria eDNA detection, highlighting the importance of water levels in nutria behavior. The study showcases the sensitivity and efficiency of eDNA assays, emphasizing their value for monitoring nutria and verifying eradication.
The nutria (Myocastor coypus), also known as the coypu, is a semi-aquatic, invasive rodent native to South America that causes damage to natural riverine and wetland habitats in many parts of the ...world, including South Korea. Understanding habitat use, connectivity, and gene flow of nutria populations is critical for the sound management of local and regional ecosystems. Here, we assessed habitat suitability and connectivity in relation to the genetic structure of nutria populations in the Nakdong River Basin of South Korea. A total of 321 nutria occurrence sites and seven environmental variables were used to perform ensemble habitat suitability modeling using five species distribution models (SDMs), including boosted regression trees, maximum entropy model, random forest, generalized linear model, and multivariate adaptive regression splines. Using graph and circuit theory approaches, we assessed the population gene flow and current flow betweenness centrality (CFBC) of suitable habitats derived from the ensemble SDM. All SDMs performed well with a range of test AUC values from 0.962 to 0.970 (mean = 0.966) with true skill statistic values over 0.8. The minimum temperature of the coldest month, mean temperature of the warmest quarter, precipitation of the driest quarter, and distance from water bodies were important predictors in nutria habitat modeling. Nutria population gene flow was significantly correlated with the least-cost path distance on a cost resistance surface based on ensemble habitat suitability modeling and roads (Mantel's r = 0.60, p < 0.05). Finally, the CFBC positively correlated with the genetic diversity of nutria populations was used to identify priority control areas. Habitat suitability and connectivity modeling not only revealed environmental conditions and areas that support the survival and spread of nutrias, but also improved our understanding of the animals' genetic population structure, thereby indicating priority areas to target for eradication.