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.
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.
Hypselodont (ever-growing) teeth of lagomorphs or rodents have higher wear rates (of a magnitude of mm/week), with compensating growth rates, compared to the non-ever-growing teeth of ungulates (with ...a magnitude of mm/year). Whether this is due to a fundamental difference in enamel hardness has not been investigated so far. We prepared enamel samples (n = 120 per species) from incisors of cattle (Bos primigenius taurus) and nutria (Myocastor coypus, hypselodont incisors) taken at slaughterhouses, and submitted them to indentation hardness testing. Subsequently, samples were split into 4 groups per species (n = 24 per species and group) that were assessed for abrasion susceptibility by a standardized brush test with a control (no added abrasives) and three treatment groups (using fine silt at 4 ±1 μm particle size, volcanic ash at 96 ±9 μm, or fine sand at 166 ±15 μm as abrasives), in which enamel abrasion was quantified as height loss by before-and-after profilometry. The difference in enamel hardness between the species was highly significant, with nutria enamel achieving 78% of the hardness of cattle enamel. In the control and the fine sand group, no enamel height loss was evident, which was attributed to the in vitro system in the latter group, where the sand particles were brushed out of the test slurry by the brushes' bristles. For fine silt and volcanic ash, nutria enamel significantly lost 3.65 and 3.52 times more height than cattle. These results suggest a relationship between enamel hardness and susceptibility to abrasion. However, neither the pattern within the species nor across the species indicated a monotonous relationship between hardness and height loss; rather, the difference was due to qualitative step related to species. Hence, additional factors not measured in this study must be responsible for the differences in the enamel's susceptibility to abrasion. While the in vitro brush system cannot be used to rank abrasive test substances in terms of their abrasiveness, it can differentiate abrasion susceptibility in dental tissue of different animal species. The results caution against considering enamel wear as a similar process across mammals.
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