Leopoldamys Edwardsi Research Articles

Plant hormones mediate the interaction between oak acorn germination and rodent hoarding behaviour.

The interaction between animals and plants for seed dispersal and predation has received much attention; however, the underlying physiological mechanisms driving the responses of both seeds and animals remain unclear. We conducted a series of behaviour and physiology experiments to examine the role of plant hormones in regulating seed germination and rodent hoarding behaviour in the Quercus variabilis and Leopoldamys edwardsi systems. We found that acorns that were partially consumed by rodents had increased gibberellin (GA) levels and shortened germination time. Rodents preferred scatter-hoarded abscisic acid (ABA)-treated and intact acorns but consumed germinated and GA-treated acorns; such treatment differences disappeared for inactivated acorns by boiling water. Moreover, we found that seven potential compounds may be linked to seed germination and rodent hoarding behaviour. Our results indicate that acorns of oak showed rapid germination when facing predation risk, while rodents could identify the germination status of seeds for hoarding; GA and ABA may play an important role in regulating seed germination of oak and hoarding behaviour of rodents.

Analysis of intestinal microbial diversity in Leopoldamys edwardsi based on illumina sequencing technique

To explore the composition and diversity of the intestinal microflora of Leopoldamys edwardsi in Hainan Island. In November 2019, DNA was extracted from fecal samples of 25 adult Leopoldamys edwardsi (14 males and 11 females) in Hainan Island at the Joint Laboratory of tropical infectious diseases of Hainan Medical College and Hong Kong University. Based on the IonS5TMXL sequencing platform, single-end sequencing (Single-End) was used to construct a small fragment library for single-end sequencing. Based on Reads shear filtration and OTUs clustering. The species annotation and abundance analysis of OTUs were carried out by using mothur method and SSUrRNA database, and further conducted α diversity and β diversity analysis. A total of 1481842 high quality sequences, belonging to 14 Phyla, 85 families and 186 Genera, were obtained from 25 intestinal excrement samples of Leopoldamys edwardsi. At the level of phyla classification, the main core biota of the Leopoldamys edwardsi contained Firmicutes (46.04%),Bacteroidetes (25.34%), Proteobacteria (17.09%), Tenericutes (7.38%) and Actinobacteria (1.67%), these five phyla account for 97.52% of all phyla. The ratio of Helicobacter which occupied the largest proportion at the genus level was 12.44%, followed by Lactobacillus (11.39%), Clostridium (6.19%),Mycoplasma (4.23%) and Flavonifractor (3.52%). High throughput sequencing analysis showed that the intestinal flora of Leopoldamys edwardsi in Hainan Island was complex and diverse, which had the significance of further research.

Habitats Show More Impacts Than Host Species in Shaping Gut Microbiota of Sympatric Rodent Species in a Fragmented Forest.

Gut microbiota play a significant role for animals to adapt to the changing environment. Host species and habitats are key drivers in shaping the diversity and composition of the microbiota, but the determinants of composition of the sympatric host gut microbiome remain poorly understood within an ecosystem. In this study, we examined the effects of habitats of different succession stages and host species on the diversity and composition of fecal gut microbiota in four sympatric rodent species (Apodemus draco, Leopoldamys edwardsi, Niviventer confucianus, and Niviventer fulvescens) in a subtropical forest. We found, as compared to the differences between species, habitat types showed a much larger effect on the gut microbiota of rodents. Alpha diversity of the microbial community of A. draco, N. fulvescens, and N. confucianus was highest in farmland, followed by primary forest and shrubland, and lowest in secondary forest. Beta diversity of the three rodent species showed significant different among habitats. The alpha diversity of gut microbiota of L. edwardsi was significantly higher than those of A. draco and N. confucianus, and its beta diversity showed significant difference from A. draco. Our results suggested that gut microbiota were important for animals in responding to diet changes in different habitats under human disturbances.

Dual ecological functions of scatter-hoarding rodents: pollinators and seed dispersers of Mucuna sempervirens (Fabaceae).

Double mutualism, that is, pollination and seed dispersal of the same plant species mediated by the same animal partners, is important but remains elusive in nature. Recently, rodent species were found as key pollinators (i.e. explosive openers) for some Mucuna species in (sub)tropical Asia, but no evidence has shown whether and how these rodents could also act as legitimate seed dispersers via scatter-hoarding for those producing large seeds. Here, my aim was to test the hypothesis that scatter-hoarding rodents could act as double mutualists for both pollination and seed dispersal of the same Mucuna species, that is, Mucuna sempervirens (Fabaceae). Based on camera-trapping survey at 2 locations with or without squirrel presence in the Dujiangyan subtropical forests, Southwest China, 7 mammals and birds were identified as explosive openers for M. sempervirens flowers, but Leopoldamys edwardsi (rats) and Paguma larvata (civets) were the main pollinators at the squirrel-absent site, while Callosciurus erythraeus (squirrels) were the main pollinators at the squirrel-present site. By tracking the fate of individually-tagged seeds over 5 years at each site, I provide the first evidence for seed-eating rodents as legitimate seed dispersers via scatter-hoarding of seeds in this world-wide plant genus, although dispersal services were slightly reduced at squirrel-absent site. More importantly, the dual roles of scatter-hoarding rodents as key pollinators and seed dispersers for the same Mucuna species have shown a clear relationship of double mutualism, and their key services may be essential for population conservation of these Mucuna species in human-disturbed landscapes.

Habitat characteristics or protected area size: What is more important for the composition and diversity of mammals in nonprotected areas?

The margins of protected areas are usually considered to have greater forest degradation, and given that most mammals live outside protected areas, researchers and conservation practitioners are increasingly recognizing that nonprotected areas must be incorporated into conservation strategy. However, the strategy used to manage these areas still involves increasing the size of protected areas, while not considering the habitat characteristics and requirements of the species. In this study, during a 3‐year period, camera trap and habitat characteristic surveys were used to estimate composition, diversity, and habitat characteristics of mammals to determine habitat characteristics or increase the size of protected areas what should be considered first for mammals’ conservation in a nonprotected area near the Huangshan Mountains in Anhui Province, China. From June 2017 to October 2019, 18 species of mammals were recorded, more than in any other protected area nearby. The linear model analysis results showed that habitat characteristics of mammals were different and showed a significant correlation with their relative abundance. Most species were related to vegetation characteristics, except primates (Macaca thibetana), and rodents (Leopoldamys edwardsi). Therefore, to establish conservation policies for nonprotected areas, habitat characteristics should be of prime concern, followed by increasing the size of protected areas to provide effective refuge areas for species conservation.

High-valued seeds are remembered better: evidence for item-based spatial memory of scatter-hoarding rodents

Episodic memory of scatter-hoarding animals involves encoding and storage of memories of cached food items, in conjunction with subsequent retrieval or recovery. Although the reward values mediate the interaction of item memory and source memory, whether nonhuman animals divide their spatial memory resources between cached items of different values has never been tested. Here, we used a unique scatter-hoarder/seed system to test our ‘cache value hypothesis’, which proposes that scatter-hoarding animals will preferentially allocate spatial memory resources towards higher-valued caches. By making Edwards's long-tailed rats, Leopoldamys edwardsi , anosmic, using Triton X-100, we showed that L. edwardsi recovered more caches containing large nuts than those containing small ones, although the two kinds of nuts were equivalently cached. Our results therefore support the hypothesis that scatter-hoarding animals allocate more spatial memory resources to caches containing high-valued items. This is one of the few studies to investigate how item memory regulates source memory (order information) in the context of food storing and recovery by animals, especially by scatter-hoarding rodents. That high-valued items were remembered better than low-valued ones in our study suggests that item memory appears to be contextually associated with order information of items in animal memory processes, which is not in agreement with a previous suggestion that order information is independent of content or item information. • We used a scatter-hoarding rodent to test episodic memory. • Edward's long-tailed rats allocated more memory on high-valued caches. • High-valued items were remembered better than low-valued ones. • The rats know ‘what food’ was cached ‘where’ or ‘when’.

Olfaction alters spatial memory strategy of scatter-hoarding animals.

Although it has been suggested that olfaction is closely interconnected with hippocampal systems, whether olfaction regulates spatial memory strategy remains never known. Furthermore, no study has examined how olfaction mediates spatial memory established on the external objects, for example, caches made by scatter-hoarding animals. Here, we experimentally induced nondestructive and reversible olfaction loss of a scatter-hoarding animal Leopoldamys edwardsi, to test whether and how olfaction regulates spatial memory to mediate cache recovery and pilferage. Our results showed that the normal L. edwardsi preferred to pilfer caches of others rather than to recover their own using accurate spatial memory (35.7% vs. 18.6%). Anosmic L. edwardsi preferred to recover the caches they made prior to olfaction loss rather than to pilfer from others relied on spatial memory (54.2% vs. 36.0%). However, L. edwardsi with anosmia showed no preference either to the caches they established after olfaction loss or caches made by others (25.8% vs. 29.1%). These collectively indicate that olfaction loss has a potential to affect new memory formation but not previously established spatial memory on caches. Our study first showed that olfaction modified spatial memory strategy in cache recovery and pilferage behaviors of scatter-hoarding animals. We suggest that future studies pay more attention to the evolution of olfaction and its relationship with spatial memory strategy.

Effects of microhabitat on rodent-mediated seed removal of endangered Kmeria septentrionalis in the karst habitat.

Seed removal behaviors of rodents are largely influenced by microhabitat. Although the karst ecosystem is composed of a broad variety of microhabitats, we have no information on how they affect such behaviors. We investigated rodents’ seed removal behaviors in four karst microhabitats (stone cavern, stone groove, stone surface, and soil surface) using three types of Kmeria septentrionalis seeds: fresh, black (intact seeds with black aril that dehydrates and darkens), and exposed (clean seeds without the aril). We show that Rattus norvegicus, Leopoldamys edwardsi and Rattus flavipectus were the predominant seed predators. Even though all seed types experienced a high removal rate in all four microhabitats, but rodents preferentially removed seeds from the three stone microhabitats (stone caves: 69.71 ± 2.74%; stone surface: 60.53 ± 2.90%; stone groove: 56.94 ± 2.91%) compared to the soil surface (53.90 ± 2.92%). Seeds that had been altered by being exposed to the environment were more attractive to rodents than fresh seeds (76.25 ± 2.20% versus 36.18 ± 2.29%). The seed removal behavior of rodents was significantly affected by the microhabitat and seed type. Finally, seeds that had fallen on the soil surface microhabitat incurred a lower predation risk than seeds fallen on other microhabitats, which increased their probability to germinate. Our results indicate that the lower predation rate of seeds from the endangered K. septentrionalis dropped on the soil surface increases trees’ likelihood of survival.

Zoonotic Helminthiases in Rodents (Bandicota indica, Bandicota savilei, and Leopoldamys edwardsi) from Vientiane Capital, Lao PDR.

Zoonotic helminths of three rodent species, Bandicota indiaca, Bandicota savilei, and Leopoldamys edwardsi, were investigated in Vientiane capital, Lao PDR. A total of 310 rodents were infected with 11 species of helminth parasites. There were 168 (54.2%) of 310 rodents infected with zoonotic helminths. From our results, there are six recorded zoonotic helminth species, and the highest prevalence was exhibited by Raillietina sp. (30.7%), followed by Hymenolepis diminuta (17.7%), Hymenolepis nana (2.6%), Echinostoma ilocanum (1.9%), Echinostoma malayanum (1.3%), and Angiostrongylus cantonensis (1%). This is the first study of zoonotic helminths in L. edwardsi and the first report of H. diminuta, H. nana, E. ilocanum, and E. malayanum in Bandicota indica and B. savilei, and the first demonstration of A. cantonenensis in B. indica in Lao PDR. From our results, these three rodents are potentially important reservoir hosts of zoonotic helminths. Thus, effective control programs should be considered for implementation to prevent the transmission of these zoonoses in this area.

Novel genotypes and multilocus genotypes of Enterocytozoon bieneusi in two wild rat species in China: potential for zoonotic transmission.

Enterocytozoon bieneusi is an opportunistic pathogen in immunodeficient patients. Although this pathogen has been reported in many domestic animals, few data are available about the occurrence of E. bieneusi in wild rats. In the current study, a total of 228 fecal samples from two wild rat species (Leopoldamys edwardsi and Berylmys bowersi) in China were examined by a nested PCR-based sequencing approach employing the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. The overall prevalence of E. bieneusi in wild rats was 33.3% (76/228), with 35.1% (39/111) in L. edwardsi and 31.6% (37/117) in B. bowersi. Ten E. bieneusi genotypes (including four known and six novel genotypes) were identified, with the novel CQR-2 (n = 15) as the predominant genotype. Phylogenetic analysis indicated that ten genotypes in the present study belong to zoonotic group 1, which contains many genotypes in humans. Furthermore, multilocus sequence typing (MLST) analysis showed that 19 ITS-positive samples were successfully amplified at three microsatellites and one minisatellite, forming 18 multilocus genotypes (MLGs). This is the first report of E. bieneusi infection in the wild rats L. edwardsi and B. bowersi. Our findings suggest that wild rats could be a significant source of human infection, including contaminated food and water.

Identification of Cryptosporidium viatorum XVa subtype family in two wild rat species in China

BackgroundCryptosporidium viatorum is a minor Cryptosporidium pathogen in humans. Currently, there is limited information regarding the prevalence and genotypes of C. viatorum in animals in China.MethodsIn this study, 228 faecal samples were collected from two wild rat species (Leopoldamys edwardsi and Berylmys bowersi) in Chongqing Municipality and Guangdong Province, China. These specimens were analyzed for C. viatorum and then subtyped it using PCR and sequence analysis of the small subunit ribosomal RNA (SSU rRNA) and 60-kilodalton glycoprotein (gp60) genes, respectively.ResultsA total of 25 (11.0%) faecal samples were tested positive for C. viatorum by SSU rRNA assay. Of these samples, 4 (3.6%) came from L. edwardsi and 21 (18.0%) from B. bowersi. Of the 25 C. viatorum-positive samples, 17 were successfully amplified at the gp60 gene locus, which represented four subtypes belonging to two subtype families, including XVa (XVaA6, XVaA3g, XVaA3h) and XVc (XVcA2G1). Phylogenetic analysis based on the gp60 amino acid sequences indicated that all of the C. viatorum isolates grouped together, supporting the conclusion that C. viatorum from the wild rats represent two subtype families.ConclusionsThese results indicate an occurrence of C. viatorum XVa subtype family from rats which is genetically identical to those found in humans. Our findings suggest that wild rats may be a potential source of human cryptosporidiosis.

Molecular Detection and Genotyping of Toxoplasma gondii in Edward's Long-Tailed Rats (Leopoldamys edwardsi).

Toxoplasma gondii is an important zoonotic parasite infecting humans and various animals with a worldwide distribution. However, limited information is available on T. gondii infection in wild rats. The present study aimed to examine the prevalence and characterize the genotypes of T. gondii in wild rats in two regions of China. Brain tissues were collected from 111 Edward's long-tailed rats (Leopoldamys edwardsi) and 117 Bower's white-toothed rats (Berylmys bowersi) between November 2017 and January 2018. Genomic DNA was extracted and amplified by PCR targeting the T. gondii B1 gene. B1 gene-positive samples were genotyped at 10 genetic markers (SAG1, SAG2 [5', 3'] and [alternative], SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico) using multilocus nested polymerase chain reaction/restriction fragment length polymorphism. Six (5.41%, 6/111) Edward's long-tailed rats from Chongqing Municipality were positive for T. gondii B1 gene, whereas no T. gondii infection was detected in Bower's white-toothed rats (n = 117) from Guangdong province. T. gondii prevalence in female and male rats was 1.77% (2/113) and 3.48 (4/115), respectively. Four of the six positive DNA samples were completely genotyped at 10 genetic loci and were identified as ToxoDB#20. The present study revealed the occurrence of T. gondii infection in Edward's long-tailed rats. These findings raised public health concerning about T. gondii infection in wild rats. These results provide reference data for understanding the distribution of T. gondii genotypes in wild rats in China.

Molecular phylogeographic analyses and species delimitations reveal that Leopoldamys edwardsi (Rodentia: Muridae) is a species complex.

Leopoldamys edwardsi is a species with wide distribution ranges in southern China but is not discussed in studies on geographic variation and species differentiation. We used 2 mitochondrial (Cytb, CO1) and 3 nuclear (GHR, IRBP and RAG1) genes to clarify species phylogeography and geographical differentiation. Maximum likelihood (ML) and Bayesian phylogenetic inference (BI) trees consistently indicated that L. edwardsi is a species complex containing 3 main lineages with high Kimura-2-parameter (K2P) divergences (i.e. lineages LN , LS and LHN ) found in the northern and southern China and Hainan Island, respectively. The 3 species delimitation methods, automated barcoding gap discovery, Bayesian poisson tree process analysis and Bayesian phylogenetics and phylogeography, consistently supported the existence of cryptic species. Divergence times among the main lineages were inferred to be during the Pleistocene, with LHN /LS split at 1.33 Ma and LN /(LHN +LS ) at 2.61 Ma; the diversifications of L. edwardsi complex might be caused by the rapid uplifts of Tibetan Plateau, paleoclimate change and complex topography. The divergence between LHN and LS was probably related to the separation of Hainan Island from the mainland via the formation of the Qiongzhou Strait. Lineages LN and (LS +LHN ) likely diverged due to the Wuyi-Nanling mountain range forming a dispersal barrier. Our results suggested that L. edwardsi complex contains at least 3 distinct species: LHN represents L. hainanensis, endemic to Hainan Island and previously considered as a subspecies L. e. hainanensis; LS represents a cryptic species distributed throughout the southern Chinese continent; and LN represents the nominotypical species L. edwardsi.

Cryptosporidium spp. in wild rats (Rattus spp.) from the Hainan Province, China: Molecular detection, species/genotype identification and implications for public health.

Wild rats (Rattus spp.) carry many zoonotic pathogens including Cryptosporidium. Due to the close proximity of rats to humans in urban environments, the potential for disease transmission is high. Cryptosporidium is a protozoan parasite which when ingested causes serious human illness. Despite its importance, genetic characterization of Cryptosporidium in wild rats in the Hainan province of China has not been performed. In this study, we analyzed the occurrence and genetics of Cryptosporidium in wild rats from Hainan, China. From December 2017 to October 2018, 150 wild rats were captured and fresh fecal material was collected from intestinal sections. Rat species were identified by PCR-based amplification and analysis of the vertebrate cytochrome b (cytb) gene. Cryptosporidium was examined by PCR amplification of the partial small subunit of ribosomal DNA (SSU rDNA). C. viatorum were subtyped by PCR analysis of the gp60 gene. A total of four rat species were identified including Asian house rats (Rattus tanezumi) (n = 46), brown rats (Rattus norvegicus) (n = 56), Edward's long-tailed rats (Leopoldamys edwardsi) (n = 38) and muridae (Niviventer fulvescens) (n = 10), with Cryptosporidium positive rates of 73.9%, 28.6%, 55.3% and 40.0%, respectively (average infection rate: 50.0%, 75/150. Sequence analysis confirmed the presence of four Cryptosporidium species and two genotypes including C. viatorum (n = 11); C. occultus (n = 2); C. muris (n = 1); and C. erinacei (n = 1); rat genotypes III (n = 13) and IV (n = 47). Three novel subtypes of C. viatorum were identified in 6 of the 11 infected Edward's long-tailed rats: XVcA2G1a (n = 4), XVcA2G1b (n = 1) and XVdA3 (n = 1). The identification of human pathogenic C. viatorum and zoonotic C. occultus, C. muris and C. erinacei, suggested that wild rats infected with Cryptosporidium pose a threat to human health. Taken together, these findings highlight the need to control the rat population in Hainan, China. The need to improve the public awareness of the risk of disease transmission from wild rats to humans is also highlighted.

New records of rodent species in Bangladesh: taxonomic studies from rodent outbreak areas in the Chittagong hill tracts

Rodents are regarded as crop pests, significant reservoirs and vectors for many zoonotic diseases around the world. Basic taxonomic information of rodents present in a locality can help understand which species are responsible as crop pest in that habitat. The phenomenon of the 50-year cycle of gregarious bamboo flowering and rodent outbreaks in the Chittagong Hill Tracts (CHT) of Bangladesh, rodents trapping were carried out in four habitats from March, 2009 to December, 2011 in Ruma upazila of Bandarban hill district. Variety of traps were used to capture small mammals. The captured species were measured and identified using taxonomical dichotomous keys and DNA bar-coding performed in Australia. A total of 14 different small mammalian species were captured of which nine belonging to the Muridae family, and one species each of Spalacidae, Sciuridae, Tupaiidae and Soricidae families. The dominant small mammal species captured were Rattus rattus (54.06%) followed by Mus musculus (26.39%), Rattus nitidus (10.98%), Suncus murinus (5.45%), Mus terricolor (1.09%), Mus cookii nagarum (0.97%), Cannomys badius (0.16%), Leopoldamys edwardsi (0.12%), Berylmys bowersi (0.12%), Vernaya fulva (0.08%), Rattus andamanensis (0.08%), Tupaia glis (0.04%) and Callosciurus pygerythrus (0.04%). Rattus nitidus, Leopoldamys edwardsi, Vernaya fulva, Rattus andamanensis, Berylmys bowersi and Mus cookii nagarum are new records of rodent species in Bangladesh. Ten individuals of Mus spp. (0.40%) were not identified to species level, requiring further genetic analysis to determine their species. The implications of these discoveries are discussed in terms of agricultural pests.
 Bangladesh J. Zool. 46(2): 217-230, 2018

Does scatter-hoarding of seeds benefit cache owners or pilferers?

The scatter‐hoarding behavior of granivorous rodents plays an important role in seed dispersal and seedling regeneration of trees, as well as the evolution of several well‐known mutualisms between trees and rodents in forest ecosystems. Because it is difficult to identify seed hoarders and pilferers under field conditions by traditional methods, the full costs incurred and benefits accrued by scatter‐hoarding have not been fully evaluated in most systems. By using infrared radiation camera tracking and seed tagging, we investigated the benefits and losses of scatter‐hoarded seeds (Camellia oleifera) for 3 sympatric rodent species (Apodemus draco, Niviventer confucianus and Leopoldamys edwardsi) in a subtropical forest of Southwest China during 2013 to 2015. We established the relationships between the rodents and the seeds at the individual level. For each rodent species, we calculated the cache recovery rate of cache owners, as well as conspecific and interspecific pilferage rates. We found that all 3 sympatric rodent species had a cache recovery advantage with rates that far exceeded average pilferage rates over a 30‐day tracking period. The smallest species (A. draco) showed the highest rate of scatter‐hoarding and the highest recovery advantage compared with the other 2 larger species (N. confucianus and L. edwardsi). Our results suggest that scatter‐hoarding benefits cache owners in food competition, supporting the pilferage avoidance hypothesis. Therefore, scatter‐hoarding behavior should be favored by natural selection, and plays a significant role in species coexistence of rodent community and in the formation of mutualism between seeds and rodents in forest ecosystems.

Infection of Rodents by Orientia tsutsugamushi, the Agent of Scrub Typhus in Relation to Land Use in Thailand.

The relationship between land use structures and occurrence of the scrub typhus agent, Orientia tsutsugamushi, in small wild mammals was investigated in three provinces of Thailand: Buriram, Loei, and Nan. O. tsutsugamushi detection was performed using 16S ribosomal DNA (rDNA) amplicon sequencing approach using Miseq Illumina platform. In total, 387 animals (rodents and shrews) were examined for the infection. The 16S rDNA sequences of the bacterium were found in nine animals, namely Bandicota savilei, Berylmys bowersi, Leopoldamys edwardsi, Rattus exulans, R. tanezumi, and Rattus sp. phylogenetic clade 3, yielding 2.3% infection rate, with two new rodent species found infected by the bacterium in Thailand: B. bowersi and L. edwardsi. Using a generalized linear mixed model (GLMM) and Random Forest analyses for investigating the association between human-land use and occurrence of the bacterium, forest habitat appeared as a strong explicative variable of rodent infection, meaning that O. tsutsugamushi-infected animals were more likely found in forest-covered habitats. In terms of public health implementation, our results suggest that heterogenous forested areas including forest-converted agricultural land, reforestation areas, or fallows, are potential habitats for O. tsutsugamushi transmission. Further understanding of population dynamics of the vectors and their hosts in these habitats could be beneficial for the prevention of this neglected zoonotic disease.

The complete mitochondrial genome of the Leopoldamys edwardsi (Rodentia: Muridae)

The complete mitochondrial genome of L. edwardsi was first sequenced and characterized. The genome was 16,284 bases in length and the composition and arrangement of its genes are analogous to most other rodents. The nucleotide sequence date of 12 heavy-strand protein-coding genes of L. edwardsi and other 26 Muridae species were used for phylogenetic analyses. Trees constructed using Maximum Likelihood, Neighbor Joining and Minimum Evolution demonstrated that L. edwardsi was closer to the genus Niviventer than Rattus. Combing previous research, it suggests that Edward’s long-tailed rat is more suitable to be classified into genus Leopoldamys and named as Leopoldamys edwardsi. This study suggested that R. edwardsi is inappropriate for the other name of L. edwardsi.

DNA barcoding of Murinae (Rodentia: Muridae) and Arvicolinae (Rodentia: Cricetidae) distributed in China.

Identification of rodents is very difficult mainly due to high similarities in morphology and controversial taxonomy. In this study, mitochondrial cytochrome oxidase subunit I (COI) was used as DNA barcode to identify the Murinae and Arvicolinae species distributed in China and to facilitate the systematics studies of Rodentia. In total, 242 sequences (31 species, 11 genera) from Murinae and 130 sequences (23 species, 6 genera) from Arvicolinae were investigated, of which 90 individuals were novel. Genetic distance, threshold method, tree-based method, online BLAST and BLOG were employed to analyse the data sets. There was no obvious barcode gap. The average K2P distance within species and genera was 2.10% and 12.61% in Murinae, and 2.86% and 11.80% in Arvicolinae, respectively. The optimal threshold was 5.62% for Murinae and 3.34% for Arvicolinae. All phylogenetic trees exhibited similar topology and could distinguish 90.32% of surveyed species in Murinae and 82.60% in Arvicolinae with high support values. BLAST analyses yielded similar results with identification success rates of 92.15% and 93.85% for Murinae and Arvicolinae, respectively. BLOG successfully authenticated 100% of detected species except Leopoldamys edwardsi based on the latest taxonomic revision. Our results support the species status of recently recognized Micromys erythrotis, Eothenomys tarquinius and E.hintoni and confirm the important roles of comprehensive taxonomy and accurate morphological identification in DNA barcoding studies. We believe that, when proper analytic methods are applied or combined, DNA barcoding could serve as an accurate and effective species identification approach for Murinae and Arvicolinae based on a proper taxonomic framework.

神农架地区4种啮齿类食性及脏器形态差异比较

PDF HTML阅读 XML下载 导出引用 引用提醒 神农架地区4种啮齿类食性及脏器形态差异比较 DOI: 10.5846/stxb201211091570 作者: 作者单位: 中国科学院植物研究所植被与环境变化国家重点实验室,中国科学院植物研究所植被与环境变化国家重点实验室,湖北神农架林区林业科学研究所,中国科学院植物研究所植被与环境变化国家重点实验室,三峡大学化学与生命科学学院,中国科学院植物研究所植被与环境变化国家重点实验室,湖北省宜昌市五峰县林业局,中国科学院植物研究所植被与环境变化国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金面上项目（No.30970474）；中国科学院战略性先导科技专项（XDA05050302） Variations in food habit and viscera organ morphology of four rodents in Shennongjia, central China Author: Affiliation: State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,State Key Laboratory of Vegetation and Environmental Change,Institute of Botany,Chinese Academy of Sciences,Shennongjia Institute of Forestry, Shennongjia Forestry Region,,College of Chemistry and Life Science, China Three Gorges University,State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences,Wufeng Forestry Bureau,State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生活在同一地域的物种，会因强烈的资源竞争而产生生态位重叠与分离，从而实现相互共存。以神农架地区啮齿动物为研究对象，比较分析不同啮齿类食性、脏器重量及消化道形态差异，探索其共存机制及其生理生态学上的适应策略。食性上，安氏白腹鼠（Niviventer andersoni）、社鼠（N. confucianus）、高山姬鼠（Apodemus chevrieri）、中华姬鼠（A. draco）均为杂食者，但各自喜食偏好不同，安氏白腹鼠的食物组成以植物枝叶和种子为主，社鼠、高山姬鼠和中华姬鼠的食物组成均以种子和动物性食物为主。与各自生态习性及其食性相适应，不同啮齿动物的脏器重量及消化道形态发生相应的变化。脏器重量上，不同啮齿动物心鲜重、肺鲜重、脾鲜重和干重无显著差异，其它指标差异显著。安氏白腹鼠的心干重、肺干重、肝鲜重和干重、肾鲜重和干重显著大于社鼠、高山姬鼠和中华姬鼠。消化道形态上，不同啮齿动物盲肠长、净鲜重和干重无显著差异，其它指标差异显著。其中，胃含内容物鲜重、净鲜重和干重，盲肠含内容物鲜重，大肠长、含内容物鲜重、净鲜重和干重均以安氏白腹鼠具较大值，但各自变化趋势不同；小肠长、含内容物鲜重、净鲜重和干重则以社鼠具较大值。且同属姬鼠属的高山姬鼠和中华姬鼠脏器重量及消化道形态各指标间均无显著差异。由于小泡巨鼠和猪尾鼠数量较少，未进行统计分析。以上结果显示：食物资源利用上的分化有利于安氏白腹鼠与其近缘物种社鼠及其他鼠类的同域共存，且为适应不同的食物资源利用模式，其脏器及消化道形态也发生了适应性的变化；同域分布的近缘物种高山姬鼠、中华姬鼠则有可能采取其它策略而非食物资源分化模式实现共存。 Abstract:The separation of ecological niches in terms of food resource, activity pattern or space contributes to the coexistence of sympatric species. Spatiotemporal variations in resource availability affect foraging behavior, habitat selection and even the existence of species. To explore the coexistence mechanisms of sympatric rodents, variations in food habit, viscera organ and digestive tract morphology among different rodent species were investigated in Shennongjia, central China.Studied rodents were trapped by snap-trap in October 2010. Upon capture, all rodents were carried to laboratory. The species, gender, age, reproductive status, body mass and length were recorded. Then the heart, lung, liver, spleen, kidney and the entire digestive tract were removed from the body and the carcass mass was weighted. The connective tissue and lipid was stripped and the digestive tract was extended to its full length. Fresh weights of all organs and lengths of digestive tract were weighted. After removing digestive tract contents, fresh weights without contents and food items in the stomach were recorded. Dry weights of all organs were measured after drying in the oven.A total of 220 adult rodents, including 8 Niviventer andersonii, 167 N. confucianus, 5 Apodemus chevrieri, and 35 A. draco, 2 Leopoldamys edwardsi and 3 Typhlomys cinereus, were collected for analysis. L. edwardsi and T. cinereus were excluded for statistical tests due to insufficient samples. The analysis of food habit showed that N. andersoni, N. confucianus, A. chevrieri and A. draco were omnivorous but the Chi-square test detected significant variation in dietary biases. N. andersoni was primarily phyllophagous and seminivorous and the others were primarily seminivorous and carnivorous. The analysis of covariance of viscera organs showed that while fresh weights of heart, lung and spleen and dry weight of spleen did not differ between rodents, other indices did exhibit significant variation with the highest value found in N. andersoni. In the analysis of digestive tract morphology, while length, fresh and dry weight of caecum did not differ between rodents, fresh and dry weights of stomach and large intestine, fresh weights including stomach, caecum and large intestine contents, and length of large intestine did differ significantly with the highest value found in N. andersoni. Otherwise, the length, fresh and dry weight of small intestine, and fresh weight including small intestine contents also showed significant variations between species, with the highest value found in N. confucianus.Variations in viscera organ morphology of N. andersoni compared to other species indicate that the segregation of food resources contributes to this species coexistence with other rodents. In order to adapt to different availability of food resources, the viscera organ and digestive tract morphology of N. andersoni show adaptable phenotypic plasticity. However, A. chevrieri and A. draco, both belonging to the genus Apodemus, do not exhibit differences in food habit, viscera organ and digestive tract morphology, which implied that their coexistence may result from other strategies than resource allocation, such as habitat selection. 参考文献 相似文献 引证文献