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Understanding the physiological adaptations of animals living in mountain landscapes is a key to predicting the responses of individuals to environmental changes, especially those imposed by climate. In this regard, the mechanism of body temperature regulation is particularly important in determining the physiological limits for activity under hypoxic and climatic stressful conditions. Numerous studies have shown that body temperature of rodents and other animals decreases with elevation and with extreme winter temperatures. But surprisingly, it is still not known how body temperature of wild animals varies along elevation during their reproductive seasons. We studied variation in core body temperature among individuals (

The extremely species-rich genus Trypanosoma has recently been divided into 16 subgenera, most of which show fairly high host specificity, including the subgenus Herpetosoma parasitizing mainly rodents. Although most Herpetosoma spp. are highly host-specific, the best-known representative, Trypanosoma lewisi, has a cosmopolitan distribution and low host specificity. The present study investigates the general diversity of small mammal trypanosomes in East and Central Africa and the penetration of invasive T. lewisi into communities of native rodents. An extensive study of blood and tissue samples from Afrotropical micromammals (1528 rodents, 135 shrews, and five sengis belonging to 37 genera and 133 species) captured in the Central African Republic, Ethiopia, Kenya, Malawi, Mozambique, Tanzania, and Zambia revealed 187 (11.2%) trypanosome-positive individuals. The prevalence of trypanosomes in host genera ranged from 2.1% in Aethomys to 37.1% in Lemniscomys. The only previously known trypanosome detected in our dataset was T. lewisi, newly found in Ethiopia, Kenya, and Tanzania in a wide range of native rodent hosts. Besides T. lewisi, 18S rRNA sequencing revealed 48 additional unique Herpetosoma genotypes representing at least 15 putative new species, which doubles the known sequence-based diversity of this subgenus, and approaches the true species richness in the study area. The other two genotypes represent two new species belonging to the subgenera Ornithotrypanum and Squamatrypanum. The trypanosomes of white-toothed shrews (Crocidura spp.) form a new phylogroup of Herpetosoma, unrelated to flagellates previously detected in insectivores. With 13 documented species, Ethiopia was the richest region for trypanosome diversity, which corresponds to the very diverse environments and generally high biodiversity of this country. We conclude that besides T. lewisi, the subgenus Herpetosoma is highly host-specific (e.g., species parasitizing the rodent genera Acomys and Gerbilliscus). Furthermore, several newly detected trypanosome species are specific to their endemic hosts, such as brush-furred mice (Lophuromys), dormice (Graphiurus), and white-toothed shrews (Crocidura).

1.Evidence that exposure to environmental pollutants can alter the gut microbiota composition of wildlife includes studies of rodents exposed to radionuclides. 2.Antwis et al. (2021) used amplicon sequencing to characterise the gut microbiota of four species of rodent (Myodes glareolus, Apodemus agrarius, A. flavicollis and A. sylvaticus) inhabiting the Chernobyl Exclusion Zone (CEZ) to examine possible changes in gut bacteria (microbiota) and gut fungi (mycobiota) associated with exposure to radionuclides and whether the sample type (from caecum or faeces) affected the analysis. 3.The conclusions derived from the analyses of gut mycobiota are based on data that represent a mixture of ingested fungi (e.g. edible macrofungi, polypores, lichens and ectomycorrhizae) and gut mycobiota (e.g. microfungi and yeasts), which mask the patterns of inter- and intraspecific variation in the authentic gut mycobiota. 4.Implying that ‘faecal samples are not an accurate indicator of gut composition’ creates an unnecessary controversy about faecal sampling because the comparison of samples from the caecum and faeces confounds many other possible drivers (including different animals from different locations, sampled in different years) of variation in gut microbiota. 5.It is relevant also that Antwis et al.'s (2021) data lack statistical power to detect an effect of exposure to radionuclides on the gut microbiota because (1) all of their samples of Apodemus mice had experienced a medium or high total absorbed dose rate and (2) they did not collect samples of bank voles (M. glareolus) from replicate contaminated and uncontaminated locations. 6.Discussion of Antwis et al.'s (2021) analysis, especially the claims presented in the Abstract, is important to prevent controversy about the outcome of research on the biological impacts of wildlife inhabiting the CEZ. peerReviewed

The African spiny mouse (Acomys cahirinus) is an emerging model of mammalian epimorphic regeneration that has aroused the interest of the scientific community in the last decade. To date, studies on brain repair have been hindered by the lack of knowledge on the neuroanatomy of this species. Here, we present a coronal brain atlas in stereotaxic coordinates, which allows for three-dimensional identification and localization of the brain structures of this species. The brain of 12-week-old spiny mice was mapped in stereotaxic coordinates using cresyl violet-stained brain sections obtained from coronal cryosectioning of the brain after transcardial perfusion with fixative. The atlas is presented in 42 plates representing sections spaced 240 mu m apart. Stereotaxic coordinates were validated using both a model of Parkinsonian lesion of the striatum with 6-hydroxydopamine and labeling of the corticospinal tract in the spiny mouse spinal cord using AAV1/2-GFP intracortical injections. This work presents a new tool in A. cahirinus neurobiology and opens new avenues of research for the investigation of the regenerative ability of A. cahirinus in models of brain disorders. info:eu-repo/semantics/publishedVersion

The ability to distinguish between familiar and strange conspecifics is important in group-living animals and influences the types of interactions between conspecifics. Social systems differ in sister taxa of the striped mouse genus Rhabdomys originating from different environments. Xeric-adapted R. pumilio displays facultative group-living whereas the mesic-adapted R. d. chakae is solitary. We assessed social recognition and attraction to strangers in females of two populations each of R. pumilio and R. d. chakae by means of a social discrimination task. We used a three-chamber apparatus developed in an established protocol and measured the latency of test females to approach and the duration of their investigation of stimulus females. Differences in social recognition of and preference for unfamiliar conspecifics in group-living and solitary-living taxa occurred at the taxon-level, even though constituent populations occurring kilometers apart showed similar responses. Females differed in the latency (testing phase) and duration of investigation (familiarization and testing phases) inter-specifically but not intra-specifically. Female R. pumilio approached stimulus females faster than female R. d. chakae. Female R. pumilio also investigated stimulus females for longer, regardless of stimulus type compared to R. d. chakae, but both taxa spent more time investigating familiar females than novel females and approached the familiar females faster than novel females. Social recognition, short-term memory, and social preference do not appear to differ between closely related taxa and differences in behavior between the two taxa might be related to inherent personality and social proclivity.

This preliminary report concerns the micromammalian remains recovered from the Pleistocene strata in Excavation 1 at Wonderwerk Cave by Peter B. Beaumont during the 1980s and early 1990s. Because of the large size of the samples (170 656 specimens representing a minimum of 71 304 individuals), identification has so far only been taken to the generic level. Remains belonging to 34, and possibly 36, genera in five Orders have been identified, and there could be as many as 48 species represented. The uneven horizontal distribution of material throughout the excavation indicates probable roost or nest sites of Barn owls (Tyto alba), which is the most likely predator responsible for their accumulation. There is also considerable vertical variation in the amount of material in the different levels, which indicates that the predators were not consistently present in the area throughout the period represented by the deposits. In the majority of the samples, Gerbillinae (Gerbilliscus, gerbils) are best represented when supra-generic groupings are used. This suggests that conditions were reasonably arid during the periods represented by the samples but not necessarily throughout the entire period spanned by the deposits. When original groupings (genus and above) are considered, Otomyinae (Otomys spp., vlei rats) predominate in nearly half the samples. Secondarily important prey taxa are shrews (Soricidae), rats and mice (Murinae) and elephant shrews (Macroscelididae). This implies some variation in environmental conditions over time but more detailed interpretations must await further analysis. In particular it is imperative to identify the species of Gerbilliscus and Otomys before progress can be made. A range of techniques is now available to assist with interpreting the samples to their full potential once this has been done.

Context Sperm morphology varies greatly across mammalian species and this variability is especially evident in murid rodents with both sperm head shape and tail length being sexually selected traits. The Palawan spiny rat, Maxomys panglima has a longer sperm tail than that currently recorded for any other mammalian species. Aims The aim of the current study was to determine the sperm morphology of an individual Palawan spiny rat, M. panglima. Methods Light and transmission electron microscopy were carried out. Key results We found that the sperm tail of M. panglima has an average length of 380 μm with the midpiece being approximately 185 μm in length with comparatively small mitochondria but very large coarse fibres. Furthermore, the sperm head has a less acutely flexed apical hook than that of most other murid rodents including those of several other Maxomys species. Conclusions The Palawan spiny rat has a highly divergent sperm morphology with an extremely long tail. It may turn out to be an important species for testing various hypotheses of sperm form and function in mammals. Implications These findings suggest markedly different selective pressures may have resulted in this unique sperm morphology, the functional significance of which remains to be determined.

Seed traits play an important role in affecting seed preference and hoarding behaviors of small rodents. Despite greatly affected by seed traits, seed detectability of competitors represents pilfering risks and may also modify seed hoarding preference of animals. However, whether seed traits and seed detectability show consistent effects on seed hoarding preference of animals remain largely unknown. Here, we explored how seed traits and seed detectability correlate with seed hoarding preference of Leopoldamys edwardsi and Apodemus chevrieri in a subtropical forest. Despite the effects of seed coat thickness and caloric value on hoarding preference of L. edwardsi, we detected no significant effects of other seed traits on hording preference of the 2 rodent species. There was no correlation between larder-hoarding preference and inter- or intra-specific seed detectability of L. edwardsi; however, seed detectability of L. edwardsi was negatively correlated with its own scatter-hoarding preference. Although scatter-hoarding preference of A. chevrieri was not correlated with inter- and intra-specific seed detectability, larder-hoarding preference of A. chevrieri was positively correlated with intra-specific seed detectability. Our study may provide evidence that intra-specific seed detectability rather than seed traits and inter-specific pilfering risks play an important role in modifying seed hoarding preference of rodents.

Rodents are the primary hosts of Bartonella species and carry more than 22 Bartonella species. However, the information on epidemiological characteristics and genetic diversity of Bartonella species in rodents in southeastern China is limited. From 2015 to 2020, 1,137 rodents were captured. Bartonella-positive DNA was detected in 14.9% (169/1,137) of rodents by PCR for both the ssrA and gltA genes. A highest Bartonella prevalence was detected in Apodemus agrarius (33.5%) and lowest in B. indica (1.8%). The probability of Bartonella infection in summer (20.1%) was higher than in spring (14.6%; p = .011, OR = 1.756). Sequencing and phylogenetic analysis revealed that nine known Bartonella species were identified in rodents, including B. tribocorum, B. grahamii, B. rattimassiliensis, B. queenslandensis, B. elizabethae, B. phoceensis, B. coopersplainsensis, B. japonica and B. rochalimae. In our study, Bartonella species exhibited a strong association with their hosts. Zoonotic B. tribocorum, B. grahamii, B. elizabethae and B. rochalimae were found in synanthropic rodent species in southeastern China, which pose a potential threat to the public health. To prevent the spread of zoonotic Bartonella species to humans, preventive and control measures should be implemented, and more research is needed to confirm the pathogen's association with human disease.

We conducted a survey for group-specific indirect immunofluorescence antibody to mammarenaviruses by using Lassa fever and Mopeia virus antigens on serum specimens of 5,363 rodents of 33 species collected in South Africa and Zimbabwe during 1964–1994. Rodents were collected for unrelated purposes or for this study and stored at −70°C. We found antibody to be widely distributed in the 2 countries; antibody was detected in serum specimens of 1.2%–31.8% of 14 species of myomorph rodents, whereas 19 mammarenavirus isolates were obtained from serum specimens and viscera of 4 seropositive species. Phylogenetic analysis on the basis of partial nucleoprotein sequences indicates that 14 isolates from Mastomys natalensis, the Natal multimammate mouse, were Mopeia virus, whereas Merino Walk virus was characterized as a novel virus in a separate study. The remaining 4 isolates from 3 rodent species potentially constitute novel viruses pending full characterization.

A nationwide survey of chigger mites causing scrub typhus and an investigation of epidemiologic factors for chigger mites was conducted at 16 localities in 8 provinces in Korea during autumn 2009, 2012, and 2013. A total of 233 Apodemus agrarius were captured, and all were infested with chigger mites. The chigger index was highest in Chungcheongbuk-do in 2009 (358.3) and 2012 (290.1) and Chungcheongnam-do in 2013 (294.4). The predominant chigger mite species was Leptotrombidium pallidum in the northern and central parts and L. scutellare in the southern and western parts, Korea. L. pallidum was not found in Jellanam-do and Gyeongsangnam-do and the distribution of L. scutellare had been expanded in the northern parts of Korea. The chigger index of L. pallidum was positively correlated with temperature and negatively correlated with humidity. The incidence of scrub typhus is dependent on L. scutellare index. These findings could be helpful to monitor the distribution of chigger mites and to develop a preventive measures for scrub typhus in Korea.

STUDY QUESTIONDoes the naturally menstruating spiny mouse go through menopause?SUMMARY ANSWEROur study is the first to show a natural and gradual menopausal transition in a rodent.WHAT IS KNOWN ALREADYAge-related depletion of the human ovarian reserve (OvR) leads to menopause, the permanent cessation of menstruation and reproduction. Current rodent models of menopause are inappropriate for inferences of the human condition, as reproductive senescence is abrupt or induced through ovariectomy. The spiny mouse is the only confirmed rodent with a naturally occurring menstrual cycle.STUDY DESIGN, SIZE, DURATIONHistological assessment of virgin spiny mice occurred in females aged 6 months (n = 14), 1 year (n = 7), 2 years (n = 13), 3 years (n = 9) and 4 years (n = 9). Endocrinology was assessed in a further 9 females per age group. Five animals per group were used for ovarian stereology with additional ovaries collected at prenatal Day 35 (n = 3), day of birth (n = 5), postnatal Days 35 (n = 5) and 100 (n = 5) and 15 months (n = 5).PARTICIPANTS/MATERIALS, SETTING, METHODSMorphological changes in the reproductive system were examined using hematoxylin and eosin stains. Proliferating cell nuclear antigen immunohistochemistry assessed endometrial proliferation and sex steroids estradiol and testosterone were assayed using commercial ELISA kits.MAIN RESULTS AND THE ROLE OF CHANCEThe proportion of females actively cycling was 86% at 6 months, 71% at 1 year, 69% at 2 years, 56% at 3 years and 44% at 4 years. Uterine and ovarian weights declined steadily from 1 year in all groups and corresponded with loss of uterine proliferation (P LARGE SCALE DATAN/A.LIMITATIONS, REASONS FOR CAUTIONThis is a descriptive study in a novel research rodent whereby reagents validated for use in the spiny mouse were limited.WIDER IMPLICATIONS OF THE FINDINGSThe gradual, rather than sudden, menopausal transition suggests that the spiny mouse is a more appropriate perimenopausal model than the current rodent models in which to examine the neuroendocrine pathways that encompass all hormonal interactions in the hypothalamic–pituitary–gonadal axis. The logistic, ethical and economic advantages of such a model may reduce our reliance on primates in menopause research and enable more thorough and invasive investigation than is possible in humans.STUDY FUNDING/COMPETING INTEREST(S)Hudson Institute is supported by the Victorian State Government Operational Infrastructure Scheme. The authors declare no competing interests.

Paramyxoviruses harbored by multiple natural reservoirs pose a potential threat to public health. Jeilongvirus has been proposed as a novel paramyxovirus genus found in rodents, bats, and cats. Paramyxovirus RNA was detected in 108/824 (13.1%) Apodemus agrarius captured at 14 trapping sites in the Republic of Korea. We first present two genetically distinct novel paramyxoviruses, Paju Apodemus paramyxovirus 1 (PAPV-1) and 2 (PAPV-2). The disparity between PAPV-1 (19,716 nucleotides) and -2 (17,475 nucleotides) revealed the presence of the SH gene and length of the G gene in the genome organization. The phylogeny of PAPV-1 and -2 belonged to distinct genetic lineages of Jeilongvirus, respectively, even though these viruses were originated from A. agrarius. PAPV-1 infected human epithelial and endothelial cells, facilitating the induction of type I/III interferons, interferon-stimulated genes, and pro-inflammatory cytokines. Therefore, this study provides insights into the molecular epidemiology, genetic diversity, and virus-host interactions of novel rodent-borne paramyxoviruses.

The multimammate mouse, Mastomys natalensis, is the most common rodent pest species in sub-Saharan Africa. Currently, rodenticides are the preferred method used to reduce the population of rodent pests, but this method poses direct and indirect risks to humans and other non-target species. Fertility control is a promising alternative that has been argued to be a more sustainable and humane method for controlling rodent pests. In this study, we compared the effectiveness of fertility control bait EP-1 (quinestrol (E) and levonorgestrel (P), 10 ppm) and an anticoagulant rodenticide bait (bromadiolone, 50 ppm) on the population dynamics of M. natalensis in maize fields in Zambia during 2 cropping seasons. M. natalensis was the most abundant species in maize fields (77% of total captures). Fertility control reduced the number of juveniles and suppressed population growth of M. natalensis at the end of the 2019–2020 cropping season. The population density initially decreased after rodenticide treatment, but the population rapidly recovered through immigration. None of the treatments influenced maize damage by rodents at germination (F2,67 = 1.626, P = 0.204). Applying the treatments during the maize seeding time was effective at suppressing population growth at the end of the cropping season than application the month before maize seeding. This research indicates that a single-dose delivery of EP-1 and rodenticide have comparable effects on the population dynamics of M. natalensis. These findings are important in developing fertility control protocols for rodent pest populations to reduce maize crop damage and improve yields.

The loss of a particular species from a community may have different effects on its functioning, depending on the presence or absence of functionally similar or phylogenetically close species in that community (redundancy). Redundancy is thus defined as the fraction of species diversity not expressed by functional or phylogenetic diversity. We assessed functional and phylogenetic alpha- and beta-redundancy in helminth and flea assemblages of two species of South African rodents, Rhabdomys dilectus and Rhabdomys pumilio, using community uniqueness as the inverse indicator of redundancy. We asked whether patterns of functional and phylogenetic alpha- and beta-uniqueness differed between (i) parasite groups (endo- versus ectoparasites), (ii) host species within parasite groups, and (iii) biomes within host species. We found differences between the two hosts in the functional and phylogenetic alpha-uniqueness (but not beta-uniqueness) of flea, but not helminth, assemblages. Significant correlations between the alpha-uniqueness of parasite assemblages and the total parasite prevalence were found only for phylogenetic uniqueness and only in helminths. Pairwise site-by-site dissimilarities in uniqueness (beta-uniqueness) and pairwise dissimilarity in prevalence were significantly associated (positively) in helminths but not in fleas. A between-biome difference in functional (but not phylogenetic) alpha-uniqueness was found in both helminth and flea assemblages harboured by R. pumilio. We conclude that the resilience of parasite assemblages in terms of the effect on hosts depends not only on their transmission strategy but also on traits of host species and environmental factors.

Background Ischemic heart disease and the resulting heart failure continue to carry high morbidity and mortality, and a breakthrough in our understanding of this disorder is needed. The adult spiny mouse (Acomys cahirinus) has evolved the remarkable capacity to regenerate full-thickness skin tissue, including microvasculature and cartilage, without fibrosis or scarring. We hypothesized that lack of scarring and resulting functional regeneration also applies to the adult Acomys heart. Methods and results We compared responses of the Acomys heart to CD1 outbred Mus heart following acute left anterior descending coronary artery ligation to induce myocardial infarction. Both Acomys and Mus hearts showed decreased ejection fraction (EF) after ligation. However, Acomys hearts showed significant EF recovery to pre-ligation values over four weeks. Histological analysis showed comparable infarct area 24-h after ligation with a similar collateral flow in both species' hearts, but subsequently, Acomys displayed reduced infarct size, regenerated microvasculature, and increased cell proliferative activity in the infarcted area. Conclusions These observations suggest that adult Acomys displays remarkable cardiac recovery properties after acute coronary artery occlusion and may be a useful model to understand functional recovery better. Translational perspective Adult Acomys provides a novel mammalian model to further investigate the cardioprotective and regenerative signaling mechanisms in adult mammals. This opens the door to breakthrough treatment strategies for the injured myocardium and help millions of patients with heart failure secondary to tissue injury with irreversible damage.

Background The Nile rat (Avicanthis niloticus) is an important animal model because of its robust diurnal rhythm, a cone-rich retina, and a propensity to develop diet-induced diabetes without chemical or genetic modifications. A closer similarity to humans in these aspects, compared to the widely used Mus musculus and Rattus norvegicus models, holds the promise of better translation of research findings to the clinic. Results We report a 2.5 Gb, chromosome-level reference genome assembly with fully resolved parental haplotypes, generated with the Vertebrate Genomes Project (VGP). The assembly is highly contiguous, with contig N50 of 11.1 Mb, scaffold N50 of 83 Mb, and 95.2% of the sequence assigned to chromosomes. We used a novel workflow to identify 3613 segmental duplications and quantify duplicated genes. Comparative analyses revealed unique genomic features of the Nile rat, including some that affect genes associated with type 2 diabetes and metabolic dysfunctions. We discuss 14 genes that are heterozygous in the Nile rat or highly diverged from the house mouse. Conclusions Our findings reflect the exceptional level of genomic resolution present in this assembly, which will greatly expand the potential of the Nile rat as a model organism.

Urbanization is rapidly transforming much of Southeast Asia, altering the structure and function of the landscape, as well as the frequency and intensity of the interactions between people, animals, and the environment. In this study, we explored the impact of urbanization on zoonotic disease risk by simultaneously characterizing changes in the ecology of animal reservoirs (rodents), ectoparasite vectors (ticks), and pathogens across a gradient of urbanization in Kuching, a city in Malaysian Borneo. We sampled 863 rodents across rural, developing, and urban locations and found that rodent species diversity decreased with increasing urbanization—from 10 species in the rural location to 4 in the rural location. Notably, two species appeared to thrive in urban areas, as follows: the invasive urban exploiter Rattus rattus ( n = 375) and the native urban adapter Sundamys muelleri ( n = 331). R. rattus was strongly associated with built infrastructure across the gradient and carried a high diversity of pathogens, including multihost zoonoses capable of environmental transmission (e.g., Leptospira spp.). In contrast, S. muelleri was restricted to green patches where it was found at high densities and was strongly associated with the presence of ticks, including the medically important genera Amblyomma , Haemaphysalis , and Ixodes . Our analyses reveal that zoonotic disease risk is elevated and heterogeneously distributed in urban environments and highlight the potential for targeted risk reduction through pest management and public health messaging.

Abstract South African small mammals are under-represented in DNA barcoding efforts, particularly from the eastern forested regions of the country. This study reports DNA barcoding of Rhabdomys taxa from previously unsampled parts of the Eastern Cape and KwaZulu-Natal provinces of South Africa. The complete mitochondrial DNA cytochrome oxidase I (COI) gene was sequenced for 101 Rhabdomys sp. individuals from 16 localities from all three main forest groups (coastal, mistbelt, and scarp forests). Molecular data were supplemented with external morphological measurements, including those deemed potential taxonomically diagnostic characters. Findings indicate the area to be inhabited solely by Rhabdomys dilectus chakae. Haplotypes distributed across the three forest groups were separated by shallow sequence divergences ranging from 0.001–0.015 (Kimura 2-parameter model) and displayed very little population genetic structure (FST= 0.071787). Morphological data revealed some regional metric differences in external morphology, but all the head-and-body to tail (HB: tail) ratios match that of R. d. chakae, and consequently, molecular and morphological data are congruent. These data confirm a range extension of R. d. chakae, supporting the utility of COI barcodes in the identification of small mammalian species.

Species or populations are locally adapted to the environments they occupy because of different selection pressures. Our study considers behavioral differences in rodents originating from environments with different levels of overhead cover. We investigated exploratory behavior and anxiety in 4 populations of the African striped mouse Rhabdomys, in South Africa, from different environments: R. pumilio from a semi-desert; R. bechuanae and R. d. dilectus, which were sympatric in the central grasslands; and another allopatric R. d. dilectus occurred in the northern grasslands. We tested all individuals in 5 standard laboratory tests: light-dark, startle response, open field and novel object tests, and the plus maze. In a principle components analysis, R. pumilio and the central grassland R. dilectus grouped together, and R. bechuanae and the allopatric R. dilectus grouped together, but there was some overlap between populations. Univariate analyses showed population-level differences in exploration and anxiety. R. pumilio and the central R. d. dilectus were more exploratory and less anxious than R. bechuanae and the allopatric R. d. dilectus. The behavior of R. pumilio (more exploratory and less anxious) reflects the open environments it occupies in nature, whereas the allopatric R. d. dilectus and R. bechuanae were less exploratory and more anxious reflecting the closed habitats they occupy. The similarity between R. pumilio and the central R. d. dilectus cannot be explained by habitat and might be related to the effects of coexistence between central grassland R. d. dilectus and R. bechuanae, which may potentially alter the behavior of one or both species. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The nonapeptides vasopressin (VP) and oxytocin (OT) are present in some form in most vertebrates. VP and OT play critical roles in modulating physiology and are well-studied for their influences on a variety of social behaviors, ranging from affiliation to aggression. Their anatomical distributions have been mapped for numerous species across taxa, demonstrating relatively strong evolutionary conservation in distributions throughout the basal forebrain and midbrain. Here we examined the distribution of VP-immunoreactive (-ir) and OT-ir neurons in a gregarious, cooperatively breeding rodent species, the spiny mouse (Acomys cahirinus), for which nonapeptide mapping does not yet exist. Immunohistochemical techniques revealed VP-ir and OT-ir neuronal populations throughout the hypothalamus and amygdala of males and females that are consistent with those of other rodents. However, a novel population of OT-ir neurons was observed in the median preoptic nucleus of both sexes, located dorsally to the anterior commissure. Furthermore, we found widespread sex differences in OT neuronal populations, with males having significantly more OT-ir neurons than females. However, we observed a sex difference in only one VP cell group – that of the bed nucleus of the stria terminalis (BST), a VP neuronal population that exhibits a phylogenetically widespread sexual dimorphism. These findings provide mapping distributions of VP and OT neurons in Acomys cahirinus. Spiny mice lend themselves to the study of mammalian cooperation and sociality, and the nonapeptide neuronal mapping presented here can serve as a basic foundation for the study of nonapeptide-mediated behavior in a group of highly social rodents.

The effect of combined levonorgestrel (P) and quinestrol (E) on the fertility of striped field mouse (Apodemus agrarius) has not been evaluated. We performed a series of experiments in both the laboratory and field to assess the effect of P and/or E on the fertility of A. agrarius. In the laboratory, to test the time-dependent anti-fertility effects of P and E, as well as their mixtures, 90 male striped field mice were randomly assigned to 6 treatment groups (n = 60), and a control group (n = 30). Mice in 3 treatment groups were administered 1 of the 3 compounds (1 mg⋅kg-1 [body weight] EP-1, 0.34 mg⋅kg-1 E, 0.66 mg⋅kg-1 P) for 3 successive days (another half for 7 successive days) via oral gavage; mice were then sacrificed 15 and 45 days after initiating the gavage treatment. Our findings indicated that E and EP-1 treatment, but not P or control treatment, significantly decreased the sperm count in the caudal epididymis, as well as the weight of the testes, epididymides, and seminal vesicles. Additionally, fertile female mice mated with E- and EP-1-treated males produced smaller pups. These data indicate that E and EP-1 can induce infertility in male A. agrarius. In the field, the population density of A. agrarius was significantly influenced by EP-1, and the rodent density in the treatment group was lower than that in the control group. Overall, our results indicate that EP-1 is an effective contraceptive in A. agrarius, a dominant rodent species in the farmland.

Third-stage larvae and adults of spiruroid nematodes were found from the stomach wall and stomach lumen, respectively, of Maxomys whiteheadi (Rodentia: Murinae) captured in Bukit Soeharto, Kalimantan, Indonesia. Close observation using light microscope and scanning electron microscope (SEM) revealed that it belongs to the genus Ascarops (Nematoda: Spirocercidae), possibly to Ascarops strongylina (Rudolphi, 1819). It is presumed that this species is parasitic in wild boars, Sus barbatus, in the forest of Kalimantan, and utilizes the murine as a paratenic host, in which it usually remains as third larval stage but can occasionally develop to adult stage.

The dynamics of Lassa virus (LASV) infections in rodent reservoirs and their endemic human caseloads remain poorly understood. During the endemic period, human infections are believed to be associated with the seasonal migration of Mastomys natalensis, thought to be the primary reservoir that triggers multiple spillovers of LASV to humans. It has become imperative to improve LASV diagnosis in rodents while updating their prevalence in two regions of Lassa fever endemicity in Nigeria. Rodents (total, 942) were trapped in Ondo (531) and Ebonyi (411) states between October 2018 and April 2020 for detection of LASV using various tissues. Overall, the LASV prevalence was 53.6%. The outbreak area sampled in Ondo had three and two times higher capture success and LASV prevalence, respectively, than Ebonyi State. This correlated with the higher number of annual cases of Lassa fever (LF) in Ondo State versus Ebonyi State. All rodent genera (

After the Fukushima Daiichi Nuclear Power Plant accident, we studied the chromosomal aberrations (dicentrics and translocations) in the splenic lymphocytes of wild mice inhabiting Fukushima prefecture. Here, we report the frequencies of chromosomal aberrations in large Japanese field mice (Apodemus speciosus) captured from 2012 to 2016 in a heavily contaminated area. The chromosomal aberrations were detected using newly developed 4-color FISH (fluorescence in situ hybridization) with A. speciosus chromosome 1-, 3-, 4- and 5-specific painting probes. The frequencies of chromosomal aberrations in mice captured in July 2012 and October 2014 were significantly higher than that in the mice inhabiting the non-contaminated control area; however, the frequency of chromosomal aberrations in mice captured in January 2016 was not. The frequency of chromosomal aberrations in individual mice tended to increase with certain dose rates and accumulated doses. Regression tree analyses suggested increasing chromosomal aberration rate in mice exposed to chronic radiation at dose rates of more than 1.1 mGy day-1 and at accumulated doses of more than 200 mGy. It is concluded that ambient dose rates in the most severely contaminated area of Fukushima prefecture and radiation doses to wild mice inhabiting this area decrease with time; consequently, chromosomal aberrations induced by radiation have not been detected 5 years after the accident.

This study documents the diversity of intestinal parasites in the eastern broad-toothed field mouse (Apodemus mystacinus) along the altitudinal gradient of Ibrahim River in Mount Lebanon during the spring and autumn of 2017. A total of 190 A. mystacinus were trapped in seventeen sites (6 riparian, 11 non-riparian) and examined for intestinal parasites. Eight intestinal parasites were identified including Heligmosomoides polygyrus, Trichuris muris, Syphacia frederici, Protospirura muris, and Aspiculuris tetraptera (nematodes), Hymenolepis diminuta (cestode), Brachylaima spp. (trematode), and Eimeria alorani (coccidian). Most of the trapped mice (85%) were infected with intestinal parasites and 38.84% showed concurrent infection with at least two parasitic species. The season had a significant effect on mice infection with Syphacia frederici, and mice are most likely to have infection with this nematode in spring season. The vegetation zone had a significant overall impact on mice infection with the nematodes Heligmosomoides polygyrus and Trichuris muris while gender did not influence significantly mouse infection with intestinal parasites. This is the first study that has been carried out to identify the intestinal parasite community in A. mystacinus of Ibrahim River region. The findings pave the way for future studies on intestinal parasites in rodents and the environmental variations affecting their dynamics.

Whether dietary carbohydrate (CHO) or fat is more involved in type 2 diabetes (T2DM) induction uncomplicated by dietary fiber was addressed in a spontaneous diabetic model, the diurnal Nile rat that mimics the human condition.A total of 138 male Nile rats were fed plant-based and animal-based saturated fat where 10% energy as CHO and fat were exchanged across 5 diets keeping protein constant, from 70:10:20 to 20:60:20 as CHO:fat:protein %energy. Diabetes induction was analyzed by: 1. diet composition, i.e., CHO:fat ratio, to study the impact of diet; 2.High glycemic load (GLoad) was most problematic if coupled with high caloric consumption. DiabetesBeyond the CHO:fat ratio and GLoad, neither the type of fat nor the dietary polyunsaturated/saturated fatty acid (P/S) ratio had a significant impact, suggesting

In mammals, daily physiological activities are regulated by a central circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Recently, an increasing number of studies have used diurnal grass rats to analyze neuronal mechanisms regulating diurnal behavior. However, spontaneous action potential firing rhythms in SCN neurons have not been demonstrated clearly in diurnal grass rats. Therefore, the present study examined extracellular single-unit recordings from SCN neurons in acute hypothalamic slices of Arvicanthis niloticus (Nile grass rats). The results of this study found that circadian firing rhythms with the highest frequency occurred at dusk (6.4 Hz at zeitgeber time (ZT)10-12), while the secondary peak occurred at dawn (5.6 Hz at ZT0-2), and the lowest frequency took place in the middle of the night (3.6 Hz at ZT14-16). Locomotor activity recordings from a separate group of animals demonstrated that the Nile grass rats of the laboratory colony used in this study displayed diurnal behaviors that coincided with large crepuscular peaks under 12:12 h light-dark cycles and bimodal rhythms under constant dim red light. Thus, a positive correlation between SCN firing frequencies and locomotor activity levels was observed in the Nile grass rats. Previously, behavioral coupling of action potential firings in SCN neurons has been suggested by in vivo recordings while the present study demonstrates that the sustenance of bimodal firing rhythms in grass rat SCN neurons can last at least one day in vitro.

Even when environmental variation over time and space is commonly considered as an important driver of population divergence, few evaluations of intraspecific genetic variation explicitly assess whether observed structure has been caused by or is correlated with landscape heterogeneity. Several phylogeographic studies have characterized the mitochondrial diversity ofAbrothrix olivacea, but none has incorporated landscape genetics analyses and ecological niche modeling, leaving a gap in the understanding of the species evolutionary history. Here, these aspects were addressed based on 186 single nucleotide polymorphisms, extracted from sequences of 801 bp of Cytb gene, gathered from 416 individuals collected at 103 localities in Argentina and Chile. Employing multivariate statistical analyses (gPCA, Mantel and Partial Mantel Tests, Procrustes Analysis, and RDA), associations between genetic differences and geographic and climatic distances were evaluated. Presence data was employed to estimate the potential geographic distribution of this species during historical and contemporary climatic scenarios, and to address differences among the climatic niches of their main mitochondrial lineages. The significant influence of landscape features in structuring mitochondrial variability was evidenced at different spatial scales, as well as the role of past climatic dynamics in driving geographic range shifts, mostly associated to Quaternary glaciations. Overall, these results suggest that throughout geographic range gene flow is unevenly influenced by climatic dissimilarity and the geographic distancing, and that studied lineages do not exhibit distributional signals of climatic niche conservatism. Additionally, genetic differentiation occurred by more complex evolutionary processes than mere disruption of gene flow or drift.

Background Ixodid ticks are important vectors for zoonotic pathogens, with Ixodes ricinus being the most important in Europe. Rodents are hosts of immature life stages of I. ricinus ticks and are considered main reservoirs for tick-borne pathogens, e.g. Borrelia burgdorferi. The aim of this study was to analyse the prevalence as well as genospecies and sequence type (ST) diversity of Borrelia burgdorferi sensu lato in ticks and small mammals from central Germany and to elaborate on the influence of environmental and/or individual host and vector factors on Borrelia prevalence. Methods After species identification, 1167 small mammal skin samples and 1094 ticks from vegetation were screened by B. burgdorferi sensu lato real-time polymerase chain reaction, and positive samples were characterized by multilocus sequence typing. Generalized linear (mixed) models were used to estimate how seasonality, small mammal species/tick life stage and habitat affect individual infection status. Results In total, 10 small mammal species and three tick species, Ixodes ricinus, Ixodes inopinatus (both considered members of the I. ricinus complex) and Dermacentor reticulatus, were investigated. Borrelia DNA was detected in eight host species, i.e. the striped field mouse (Apodemus agrarius), the yellow-necked field mouse (Apodemus flavicollis), the wood mouse (Apodemus sylvaticus), the water vole (Arvicola amphibius), the bank vole (Clethrionomys glareolus), the field vole (Microtus agrestis), the common vole (Microtus arvalis), and the common shrew (Sorex araneus). Two species were Borrelia negative, the greater white-toothed shrew (Crocidura russula) and the pygmy shrew (Sorex minutus). The average prevalence was 6.2%, with two genospecies detected, Borrelia afzelii and Borrelia garinii, and at least three STs that had not been previously reported in small mammals. Borrelia prevalence in small mammals did not differ between seasons. Six genospecies of Borrelia—Borrelia afzelii, Borrelia valaisiana, Borrelia garinii, Borrelia lusitaniae, Borrelia spielmanii, and Borrelia burgdorferi sensu stricto—and 25 STs of Borrelia, of which 12 have not been previously described at all and five have not been previously reported in Germany, were detected in 13% of I. ricinus complex ticks. Prevalence was highest in adult females (25.3%) and lowest in nymphs (11.4%). Prevalence was significantly higher in ticks from grassland (16.8%) compared to forests (11.4%). Conclusions The high level of small mammal diversity in this region of Germany seems to be reflected in a wide variety of genospecies and STs of B. burgdorferi. Graphical abstract

South Africa boasts a rich diversity of small mammals of which several are commensal and harbour parasites of zoonotic importance. However, limited information is available on the parasite diversity and distribution associated with rodents in South Africa. This is particularly relevant for

Rattus tiomanicus is a murid rodent of considerable agricultural and public health importance in Southeast Asia. The whole mitochondrial genome of R. tiomanicus was sequenced by the Ion Torrent PGM platform. It had a total length of 16,309 bp, consisting of 13 protein-coding genes, two rRNA genes, 22 tRNA genes and two non-coding regions (L-strand replication origin and control region). Only TAA and incomplete T-stop codons were represented in the protein-coding genes. Of the tRNAs, tryptophan (W) had ACU anticodon. The cloverleaf structure for serine S1 (AGN) tRNA lacked the entire D-arm, while in lysine (K) tRNA, the DHU arm lacked the D-loop. Molecular phylogeny based on 15 mt-genes indicated R. tiomanicus having closest genetic affinity to R. rattus complex (R. rattus, R. tanezumi). There were two major clades for the Murinae subfamily namely the Rattini tribe and the Apodemini, Murini and Hydromyini tribes. The whole mitogenome of R. tiomanicus will serve as a useful dataset for studying the systematics and phylogenetic relationships of the murid rodents.

Half of the ten Australian hopping mice (Notomys) species have become extinct following the European colonisation of Australia, and most of the rest are threatened. This makes the study of their present diversity paramount. Although recent molecular phylogenies improved our understanding of the relationships among the species, detailed interspecific phenotypic comparisons are still lacking. This is the aim of the present study. Geometric morphometric methods were used to compare the crania of all five extant species (N. alexis, N. aquillo, N. cervinus, N. fuscus, and N. mitchellii) along with the extinct N. longicaudatus. Although previous work (based on traditional approaches) find intragenerically conserved crania, the present study discovers significant differences in cranial size and shape among Notomys species, with the ventral view being more distinct than the dorsal view. There was no evidence of sexual dimorphism in cranial size nor shape, and only a weak allometric effect. Most aspects of cranial shape differed among the species. The extant species pair that differed in cranial shape the most was N. aquilo – N. cervinus, differing in the foramen magnum, tympanic bulla, orbit, incisive foramen, and rostrum, along with cranial width, potentially a consequence of N. cervinus’ phylogenetic position, and N. aquilo’s s ecological uniqueness.

A new ctenophthalmid flea species, Ctenophthalmus (Ctenophthalmus) yesarii n. sp., is described and illustrated. This new species belonging to the fransmiti group is most closely related to Ctenophthalmus (Ctenophthalmus) fransmiti Suciu. Specimens of Ct. yesarii n. sp. were collected from the eastern broad-toothed field mouse, Apodemus mystacinus (Danford & Alston), in Balikesir (Edremit district) province of Turkey. The number of Ctenophthalmus taxa known from Turkey now tallies 41 taxa (27 species and 14 subspecies).

The vast majority of neural stem cell studies have been conducted on the brains of mice and rats, the classical model rodent. Non‐model organisms may, however, give us some important insights into how to increase neural stem cell numbers for regenerative purposes and with this in mind we have characterized these cells in the brain of the spiny mouse, Acomys cahirinus. This unique mammal is highly regenerative and damaged tissue does not scar or fibrose. We find that there are more than three times as many stem cells in the SVZ and more than 3 times as many proliferating cells compared to the CD‐1 outbred strain of lab mouse. These additional cells create thick stem cell regions in the wall of the SVZ and very obvious columns of cells moving into the rostral migratory stream. In the dentate gyrus, there are more than 10 times as many cells proliferating in the sub‐granular layer and twice the number of doublecortin expressing neuroblasts. A preliminary analysis of some stem cell niche genes has identified Sox2, Notch1, Shh, and Noggin as up‐regulated in the SVZ of Acomys and Bmp2 as being down‐regulated. The highly increased neural stem cell numbers in Acomys may endow this animal with increased regenerative properties in the brain or improved physiological performance important for its survival.

Hantaviruses include several zoonotic pathogens that cause different syndromes in humans, with mortality rates ranging from 12 to 40%. Most commonly, humans get infected through the inhalation of aerosols or dust particles contaminated with virus-containing rodent excreta. Hantaviruses are specifically associated with the host species, and human cases depend on the presence and the dynamics of reservoir hosts. In this letter, we report the identification of Dobrava-Belgrade virus (DOBV) in the yellow-necked mouse (

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为探讨海南岛的小泡巨鼠肠道微生物群落组成及其菌群多样性。2019年12月于海南医学院-香港大学热带传染病联合实验室提取25只海南岛的成年小泡巨鼠（14只雄和11只雌性）粪便样本DNA，基于IonS5TMXL测序平台，利用单端测序（Single-End）的方法，构建小片段文库进行单端测序。通过对测序片段剪切过滤，操作分类单元（Operational Taxonomic Units，OTUs）聚类，利用mothur方法与SSUrRNA数据库对OTUs进行物种注释及丰度分析，并进一步开展α多样性分析（Alpha Diversity）和β多样性分析（Beta Diversity）。结果显示，从25只小泡巨鼠肠道粪便样本中共得到高质量序列1481842条，归属为14个门、85个科、186个属。从门分类水平上，小泡巨鼠的主要核心生物群有厚壁菌门（Firmicutes，46.04%），拟杆菌门（Bacteroidetes，25.34%）；随后依次为变形菌门（Proteobacteria，17.09%），柔壁菌门（Tenericutes，7.38%），放线菌门（Actinobacteria，1.67%）；这5个门占所有菌门的97.52%。属水平上螺杆菌属（

The winds of Patagonia are referred to by locals as "The Broom of God" because they sweep away the less fit species that cannot survive there. Fitness as an evolutionary trait has been considered as fundamental for many aspects of morphogenesis and behavior in metazoans. Yet, it has not received much attention in the area of wound healing, despite the obvious relevance of this polygenic trait to an organism's survival in nature. In this chapter, we review the evidence that the rodent species Acomys cahirinus is an emerging mammalian model system that has evolved a non-typical (for mammals) wound healing response that offers unique opportunities for the study of organ regeneration without fibrosis in an adult mammalian species.

Use of artificial at night (ALAN) exposes the world to continuously increasing levels and distribution of light pollution. Our understanding of the adverse effects of ALAN is based mostly on observational or laboratory studies, and its effects are probably underestimated. Demonstration of direct experimental fitness consequences of ALAN on mammals is missing. We studied the effects of chronic light pollution at different wavelengths on fitness and glucocorticoid hormone levels under semi-natural conditions in two closely related species: the nocturnal common spiny mouse (Acomys cahirinus) and the diurnal golden spiny mouse (Acomys russatus). Our results clearly demonstrate the adverse effects of ALAN exposure on the fitness of both nocturnal and diurnal species, manifested by changes in cortisol levels and reproductive timing, reduced reproductive output and reduced survival, which differed between species and wavelengths. In A. russatus exposure to blue ALAN had the strongest effect on fitness, followed by white and yellow ALAN exposure. In A. cahirinus the results are more complex and suggest it suffered from the combined effects of ALAN and competition. Our research shows that light pollution presents a real threat to both nocturnal and diurnal species, affecting the species fitness directly and through interspecific interactions. Worryingly, these effects are probably not limited to spiny mice. The clear adverse effects we documented, as well as the differences between wave lengths, contribute to our ability to present science-based recommendations to decision makers regarding the use of artificial light at night. Such information and guidelines are highly important nowadays when lighting systems are being replaced to promote energy efficiency.

Although certain organisms are chosen and employed to better understand a specific problem in biology (so-called model organisms), sometimes an animal model reveals its' biomedical importance by happenstance. In many ways, the advent of spiny mice (Acomys) as an emerging model to study regeneration and menstruation stands as a case study in scientific pseudoserendipity (Diaz de Chumaceiro, 1995). As we recount in this chapter, the discovery of these phenotypes, while not entirely accidental, was nonetheless unexpected. In addition to recounting how we uncovered these unusual mammalian traits, we outline recent work by our groups and others that has begun to outline the cellular and genetic mechanisms underlying bonafide mammalian tissue regeneration and a human-like mode of reproduction in spiny mice.

Significance Whether sympatric speciation (SS) is rare or common is still debated. Two populations of the spiny mouse, Acomys cahirinus , from Evolution Canyon I (EC I) in Israel have been depicted earlier as speciating sympatrically by molecular markers and transcriptome. Here, we investigated SS both genomically and methylomically, demonstrating that the opposite populations of spiny mice are sister taxa and split from the common ancestor around 20,000 years ago without an allopatric history. Mate choice, olfactory receptors, and speciation genes contributed to prezygotic/postzygotic reproductive isolation. The two populations showed different methylation patterns, facilitating adaptation to their local environment. They cope with abiotic and biotic stresses, due to high solar interslope radiation differences. We conclude that our new genomic and methylomic data substantiated SS.

Rodents are generally recognized to be the reservoir hosts of a great many zoonotic pathogens. In some areas of China, rodent-borne pathogens, as well as the role of rodents in the natural cycle of these pathogens, are still poorly investigated. To increase our knowledge on the distribution and epidemiology of rodent-borne bacterial pathogens, 81 rodent liver samples were collected in three locations of Guizhou province located in Southwest China, and screened for the presence of Ehrlichia, Coxiella, and Bartonella in them. A putative novel Ehrlichia species was identified in 5 Berylmys bowersi samples (100%, 5/5). Its 16S rRNA, gltA, and groEL genes have highest 99.84%, 89.11%, and 98.02% identities to those from known Ehrlichia species, and form distinct clades in the phylogenetic trees. Herein we name it "Candidatus Ehrlichia zunyiensis". Bartonella was tested positive in 8 A. agrarius (striped field mouse), 2 A. chevrieri (Chevrier's field mouse), 1 R. norvegicus (Norway rat), 1 N. confucianus, and 1 N. lotipes, with a total positive rate of 16.05% (13/81). Sequence analysis indicated high genetic diversity in these Bartonella strains. Unexpectedly, two Coxiella strains were identified from the rodents (1 Niviventer confucianus and 1 Mus pahari). Genetic and phylogenetic analysis indicated that both of them are closely related to the Coxiella endosymbiont of ticks. This result supported previous conjectures that vertebrate hosts such as rodents may play a role in the preservation and transmission of Coxiella endosymbiont of ticks.

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.

The objective of this study was to investigate evidence of emerging anaplasmosis and bartonellosis in rodents from endemic areas of Nakhon Ratchasima, Thailand. Rodent trapping was undertaken in 13 sub-districts of Muang District. The live-capture traps were set up in three locations of selected scrub typhus patient houses for three consecutive nights. Wild-caught rodent whole blood samples and associated ticks and fleas were collected and tested for Anaplasma spp. and Bartonella spp. In addition, heat maps using GIS software were used to determine the density of infection of positive wild-caught rodents. A total of 347 wild-caught rodents of nine species was captured. Rattus rattus (38.6%) was the dominant species. A total of 1,518 Heamaphysalis bandicota ticks and 57 Xenopsylla cheopis fleas was removed. Twenty-two of the 347 tested blood samples (6.3%) were Anaplasma bovis-positive and 121 blood samples and five out of 27 pools of X. cheopis fleas were Bartonella queenslandensis-positive. Of these infected rodents, dual-infections between A. bovis and B. queenslandensis were found in three B. indica rodents. Our results offer new information concerning the infections of A. bovis and B. queenslandensis in both rodents and their ectoparasites collected in high-risk areas of rodent-borne diseases in Thailand.

The semi-aquatic African murine genera Colomys and Nilopegamys are considered monotypic and thought to be closely related to one another. Colomys occurs across forested regions of equatorial Africa, whereas Nilopegamys is known only from the Ethiopian holotype, making it among the rarest mammalian genera in the world – and possibly extinct. Using morphological and genetic data, we reassess the taxonomy of Colomys and Nilopegamys. A multilocus phylogeny with outgroups demonstrates that Nilopegamys is sister to Colomys. In addition, we recognize at least four morphologically diagnosable and genetically distinct species within Colomys: C. eisentrauti (elevated from subspecies and restricted to north-west Cameroon), C. goslingi (with a more restricted range than previously reported) and two new species (one from Liberia and Guinea and one from central and southern Democratic Republic of the Congo and Angola). We also review the status of four other taxa currently recognized within Colomys goslingi (bicolor, denti, goslingi and ruandensis) and demonstrate that these names lack phylogenetic and/or morphological support. Finally, we discuss potential biogeographic barriers that may have played a role in the evolution of Colomys and Nilopegamys, emphasizing the importance of rivers in both facilitating and, possibly, limiting dispersal within these genera.

We describe the tissues and organs that show exceptional regenerative ability following injury in the spiny mouse, Acomys. The skin and ear regenerate: hair and its associated stem cell niches, sebaceous glands, dermis, adipocytes, cartilage, smooth muscle, and skeletal muscle. Internal tissues such as the heart, kidney, muscle, and spinal cord respond to damage by showing significantly reduced inflammation and improved regeneration responses. The reason for this improved ability may lie in the immune system which shows a blunted inflammatory response to injury compared to that of the typical mammal, but we also show that there are distinct biomechanical properties of Acomys tissues. Examining the regenerative behavior of closely related mammals may provide insights into the evolution of this remarkable property.

To study the environmental radiation effects of wild animals after the Fukushima Dai-ichi nuclear power plant accident, we assessed effects on hematopoietic progenitor cells (HPCs) in large Japanese field mice (A. speciosus were collected from three contaminated sites and control area. The air dose-rates at the control and contaminated areas were 0.96 ± 0.05 μGy/d (Hirosaki), 14.4 ± 2.4 μGy/d (Tanashio), 208.8 ± 31.2 μGy/d (Ide), 470.4 ± 93.6 μGy/d (Omaru), respectively. We investigated possible DNA damage and pro-inflammatory markers in the bone marrow (BM) cells. The colony-forming potential of BM cells was estimated by the number of HPC colony-forming cells. Radiation-induced genomic instability (RIGI) in HPCs was also analyzed by quantifying delayed DNA damage in CFU-GM clones.Although no significant differences in DNA damage and inflammation markers in BM cells from control and contaminated areas, the number of HPC colonies exhibited an inverse correlation with air dose-rate. With regard to RIGI, no significant differences in DNA damage of CFU-GM clones between the mice from the control and the three contaminated areas.Our study suggests that low dose-rate radiation of more than 200 Gy/d reduced HPCs, possibly eliminating genomically unstable HPCs.

Orthohantaviruses are negative-sense, single-stranded RNA viruses harbored by multiple small mammals. Dobrava-Belgrade virus (DOBV) and Puumala virus (PUUV) cause hemorrhagic fever with renal syndrome (HFRS) in Europe. In Poland, serological surveys have demonstrated antibodies against DOBV and PUUV in patients with HFRS. Molecular evidence of DOBV and PUUV has been found in Apodemus flavicollis and Myodes glareolus, respectively, in southeastern Poland, and Seewis virus (SWSV) has been reported in Sorex araneus in central Poland. However, data on the geographic distribution and phylogeny of orthohantaviruses are unavailable for other regions in Poland. To ascertain the prevalence and genetic diversity of orthohantaviruses in western and northern Poland, lung tissues from 106 small mammals were analyzed for the presence of orthohantavirus RNA. Dobrava-Belgrade virus and SWSV were detected in two of 42 (4.8%) Apodemus agrarius and in three of 10 (30%) S. araneus, respectively. Phylogenetic analyses of partial L- and S-segment sequences of DOBV indicated a shared genetic lineage with the Kurkino genotype from Slovakia, Russia, and Hungary, whereas the partial M segment of DOBV clustered with the Kurkino genotype from Germany. Phylogenetic relationships of the SWSV L and S segments showed a geographic lineage with SWSV strains from central Poland, Czech Republic, and Germany. In conclusion, the study provides an insight into the molecular prevalence, phylogenetic diversity, and evolutionary relationship of DOBV in A. agrarius and SWSV in S. araneus. This report increases awareness among physicians for HFRS outbreaks in western Poland.

Tissue regeneration is widespread in the animal kingdom. To date, key roles for different molecular and cellular programs in regeneration have been described, but the ultimate blueprint for this talent remains elusive. In animals capable of tissue regeneration, one of the most crucial stages is wound healing, whose main goal is to close the wound and prevent infection. In this stage, it is necessary to avoid scar formation to facilitate the activation of the immune system and remodeling of the extracellular matrix, key factors in promoting tissue regeneration. In this review, we will discuss the current state of knowledge regarding the role of the immune system and the interplay with the extracellular matrix to trigger a regenerative response.

Superior species may have distinct advantages over subordinates within asymmetrical interactions among sympatric animals. However, exactly how the subordinate species coexists with superior species is unknown. In the forests west of Beijing City, intense asymmetrical interactions of food competition exist among granivorous rodents (e.g. Apodemus peninsulae, Niviventer confucianus, Sciurotamias davidianus and Tscherskia triton) that have broadly overlapping habitats and diets but have varied body size (range 15–300 g), hoarding habits (scatter vs larder) and/or daily rhythm (diurnal vs nocturnal). The smallest rodent, A. peninsulae, which typically faces high competitive pressure from larger rodents, is an ideal model to explore how subordinate species coexist with superior species. Under semi‐natural enclosure conditions, we tested responses of seed‐hoarding behavior in A. peninsulae to intraspecific and interspecific competitors in the situations of pre‐competition (without competitor), competition (with competitor) and post‐competition (competitor removed). The results showed that for A. peninsulae, the intensity of larder‐hoarding increased and the intensity of scatter‐hoarding declined in the presence of intraspecifics and S. davidianus, whereas A. peninsulae ceased foraging and hoarding in the presence of N. confucianus and T. triton. A. peninsulae reduced intensity of hoarding outside the nest and moved more seeds into the nest for larder‐hoarding under competition from intraspecific individuals and S. davidianus. In most cases, the experimental animals could recover to their original state of pre‐competition when competitors were removed. These results suggest that subordinate species contextually regulate their food‐hoarding strategies according to different competitors, promoting species coexistence among sympatric animals that have asymmetrical food competition.