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We investigated the frequencies of sympatric small mammal species in 12 habitat-types located in the extreme south of the Italian peninsula (Calabria) using trapping techniques. Ten species were detected with Apodemus sylvaticus, the most abundant species. The assemblages of small mammal species recorded in the 12 selected habitat types revealed clear ecological and biogeographical patterns in the extreme southern tip of the Italian peninsula. Ecologically, we observed a clear dissimilarity between a guild of species linked to thermo-xerophilous habitat types and a comparable guild of mesophilous species linked to forest and sciaphilous habitat types. The differences among communities inhabiting in different habitat types also emerged in rarefaction curves, DCA analysis and Whittaker plots. Thus, all these sets of analyses were consistent in their interpretation of the variation of small mammal community structure along the gradient (β-diversity) among habitat types. From a biogeographical point of view, this is an apparent expression of a clear North–South gradient pattern that was already observed at the species level with Calabria being characterized by a strong impoverishment in species' richness and diversity ("peninsula effect"). However, this rationale has been based so far on indirect data of small mammals preyed upon and recorded in owl's pellets: the fact that a similar pattern was obtained also using small mammals recorded by traps indicates that the results were robust and generalizable. Ecological factors at the local scale and biogeographical factors at the peninsular scale could explain the community patterns that we observed in the present study. [ABSTRACT FROM AUTHOR]

The variability of the cytochrome b gene in 11 individuals of Korean field mouse from the Ussuri Nature Reserve located on the southern spurs of the Sikhote-Alin in the Przewalski Mountains has been analyzed. In the population, a high level of genetic diversity was identified owing to the discovery of individuals with haplotypes of three phylogenetic lineages, i.e., Amur, Korea, and Manchuria. The majority of individuals (72.73%) in the population had Amur haplotypes. A significantly lower frequency of occurrence of individuals with Korea haplotypes in the Ussuri Nature Reserve (9.09%) compared to the previously analyzed population of the Khasansky district (38.46%) located in the very south of the Primorsky krai was noted. In the Ussuri Nature Reserve, for the first time in the Russian Far East, two individuals with Manchuria haplotypes were discovered. Previously, only one finding of an individual with a similar haplotype was noted in the literature in the Heilongjiang province of Northeast China. It was suggested that individuals with haplotypes of the Korea phylogroup penetrate into the south of Sikhote-Alin from South Korea and with haplotypes of the Manchuria phylogroup from Northeast China. [ABSTRACT FROM AUTHOR]

Mites from the Demodecidae and Psorergatidae can optimally use mammalian hosts by inhabiting a number of different microhabitats in their skin. Hence, in individual hosts, several species of parasites from these groups have been described in different microhabitats. There are few data on their co-occurrence either at the host species level or at the host individual level. Most research has addressed the co-occurrence of Demodecidae in carnivorans, ungulates, soricomorphs, and rodents, while the co-occurrence of both families was found in bats. The present study examines the possibility of their co-occurrence in a Eurasian rodent—Apodemus flavicollis. It is a suitable model for such analyses, because representatives of both families have been demonstrated here so far, and our findings extend the list of specific Demodecidae in A. flavicollis with two new species: Demodex tenuis sp. nov. from the lip region and D. mediocris sp. nov. from the chin region. The study also includes the first record of Psorergates muricola in this host, which occurred in the genital–anal region. Therefore, the findings confirm the possibility that different Demodecidae and Psorergatidae species can co-occur in the same host in different body regions. This paper also includes a checklist of Demodecidae and Psorergatidae in rodents around the world. [ABSTRACT FROM AUTHOR]

Japanese walnuts (Juglans mandshurica) are known to be seed‐dispersed by the hoarding of two species of rodents, Japanese squirrels (Sciurus lis) and large Japanese field mice (Apodemus speciosus). The previous study showed that the squirrel transported and stored larger walnut seeds farther, whereas the mice transported smaller seeds farther. Divergent selection by different seed dispersers may play an important role in differentiation between local walnut populations, in which understanding seed size heritability is crucial. This study aims to determine how the seed size selected by rodents affects the initial growth of walnuts and to what extent walnut seed size is genetically determined. Sixty walnut seeds were collected from a small seed‐producing tree, and 50 walnut seeds from a large seed‐producing tree were sown and grown for 18 years. The seed size produced from each tree showed that the heritability of seed size was high (h2 = 0.52). When 50 smaller and 50 larger walnut seeds were planted under the same conditions, the dry weight of shoots and roots of the larger seeds was significantly greater than that of the smaller seeds, and root length was also significantly longer in the larger seeds. Seed size is heritable, so if squirrels are inhabiting, larger seeds, which are advantageous for regeneration, will be selected, and walnut trees producing larger seeds will be passed on to the next generation. Because selective hoarding has implications for seed establishment success, inhabiting a suitable seed disperser, the squirrel, is more critical for walnut regeneration than previously assumed. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we investigated differences in the non-fish diet components of the Grey Heron (Ardea cinerea) at both regional and local scales. We found significant inter-regional and inter-colony differences, not only in the diet but also in the habitat composition of foraging areas. We also identified significant relationships between some prey items and different habitats. This study shows that the opportunistic character of the diet of the Grey Heron is adapted to the local foraging habitat and the availability of non-fish prey. Habitat structure on foraging ground is one of the crucial factors determining diet diversity in colonially breeding avian predators. Quantifying the habitat and diet composition at different spatial scales (regional and local inter-colonial) can help provide understanding of the drivers of diet composition. In this study, we examined the composition of the non-fish diet of an opportunistic predator, the Grey Heron (Ardea cinerea), based on pellets. We compared pellets from 21 colonies in two different regions of Poland that differing in composition of foraging habitats. Multivariate statistical techniques were used to analyze the relationship between diet and habitat compositions in a 20 km radius around these colonies. Significant inter-regional and inter-colony differences in Grey Heron diet and habitat composition were detected in foraging areas. However, some prey were present in the diet only from one of the regions. Around the heronries with a predominance of farmland habitats, the European water vole (Arvicola amphibius) and terrestrial invertebrates were present in relatively low frequencies, and the striped field mouse (Apodemus agrarius) was present in high frequencies. Voles (Microtus sp.) were more frequent in colonies with prevalence of non-irrigated arable land around the colony, in contrast to the bank vole (Myodes glareolus), which was less common in heronries with a higher contribution of this habitat type. Remains of aquatic invertebrates were less abundant in colonies surrounded by extensive forests. The results of our research indicate the opportunistic character of the non-fish part of the diet of the Grey Heron adapted to the local foraging habitat and prey availability. [ABSTRACT FROM AUTHOR]

Theoretical models suggest that species abundance plays a crucial role in mutualism; high densities can lead to overexploitation. Additionally, mutualistic benefits are expected to increase under abiotic stress.We investigated the interplay between density dependence and abiotic factors in conditional mutualism, focussing on the interactions between yellow‐necked mice (Apodemus flavicollis) and common oaks (Quercus robur) across 3 years. We controlled for seed abundance, while mouse densities varied. Our approach included monitoring mouse abundance, measuring seed removal, determining the fate of harvested seeds and conducting seedling emergence trials to assess the advantages of seeds caching.We found that mouse abundance exerted a strong influence on all studied aspects of seed dispersal. Higher densities led to increased seed removal and greater dispersal distances. However, they also decreased the probability of seed caching and increased seed consumption, degrading dispersal quality and shifting the interaction towards antagonism. Furthermore, the reliance of seedling recruitment on burial varied over time, likely becoming more critical during dry conditions. This indicates that plants face the worst conditions when high abundance of mice coincides with abiotic stress.Synthesis: Our results supports the notion that increased rodent abundance reduces plant recruitment, revealing the conflicting interests of the interacting species. However, the dynamics of rodent–oak interactions are shaped not only by the density‐dependent foraging decisions of rodents, but also by the benefits of seed burial under stress. These findings illustrate how the interplay between population density and abiotic factors jointly dictate the costs and benefits of mutualistic interactions. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have contributed to the increase of heavy metals and to the alteration of their natural cycles in the environment. Mercury (Hg) is now considered to be one of the most toxic elements whose levels need to be monitored in abiogenic and biogenic environmental compartments. It can enter the body of animal in several ways, mainly through contaminated food. In this study, we compared mercury levels in mouse hair and songbird feathers from Zhongar Alatau National Park in Kazakhstan and from national parks in Slovakia. We sampled mice of the genus Apodemus and songbirds of three genera – Parus, Phylloscopus and Turdus. Total mercury concentrations were measured using DMA-80. The results showed higher levels of Hg bioaccumulation in Slovakia than in Kazakhstan in both songbirds and mice. The three songbird species from Kazakhstan showed differences due to different feeding niches. High levels were found in thrushes, which are considered insectivorous ground feeders, whereas the lowest mercury concentrations were detected in tits, which are considered more generalist feeders. In Slovakia, the trend was different, with tits having similar levels of Hg to thrushes, a reflection of the different levels of contamination of environmental components. Mice showed overall lower concentrations than birds at both sites.

A novel morbillivirus and a novel betaherpesvirus are reported in the Wood Mouse (Apodemus sylvaticus) in the western United Kingdom (UK). The two viruses were found coinfecting an underweight host with abnormalities of the liver and were detected via deep sequencing of lung RNA and de novo assembly of substantial genome fragments. The phylogenetic affinities of the novel viruses are characterised based on their relationships to existing database sequences. [ABSTRACT FROM AUTHOR]

Simple Summary: Investigating the dietary preferences and ecological niche characteristics of mammals can reveal their adaptive strategies under environmental changes, as well as the interrelationships and coexistence mechanisms among coexisting sympatric species. In this study, we analyzed the stomach contents of three coexisting rodents commonly found in the Meili Snow Mountain, Yunnan Province, China, using DNA metabarcoding technology to elucidate their food composition and diversity. The results revealed that, despite the presence of ecotope overlap, the three species were clearly separated in terms of their main food sources, suggesting that they may coexist in the same habitat by using different proportions and types of food to minimize interspecific food competition. Understanding the dietary preferences and ecological niche characteristics of mammals not only reveals their adaptive strategies under environmental changes but also reveals the interspecific relationships and coexistence mechanisms among sympatric species. Nevertheless, such data are scarce for rodents inhabiting areas spanning a wide altitude range. This study employed DNA metabarcoding technology to analyze the stomach contents of Apodemus ilex, Apodemus chevrieri, and Niviventer confucianus, aiming to investigate their dietary compositions and diversity in the Meili Snow Mountain in Yunnan Province, China. Levins's and Pianka's indices were used to compare the interspecific niche breadth and niche overlaps. The results revealed the following: (1) Insecta (relative abundance: 59.4–78.4%) and Clitellata (relative abundance: 5.2–25.5%) were the primary animal food sources for the three species, while Magnoliopsida (relative abundance: 90.3–99.9%) constitutes their main plant food source. Considerable interspecific differences were detected in the relative abundance of primary animal and plant foods among the three species; (2) There was partial overlap in the genus-level animal food between A. ilex and N. confucianus (Ojk = 0.4648), and partial overlap in plant food between A. ilex and A. chevrieri (Ojk = 0.3418). However, no overlap exists between A. chevrieri and N. confucianus, either in animal or plant food; (3) There were no significant interspecific differences in the α-diversity of animal and plant foods among the three species. The feeding strategies and ecological niche variations of these rodents support the niche differentiation hypothesis, indicating that they have diversified in their primary food sources. This diversification may be a strategy to reduce competition and achieve long-term coexistence by adjusting the types and proportions of primary foods consumed. [ABSTRACT FROM AUTHOR]

In this study, we conducted a field survey in Aichi Prefecture, central Japan, to clarify whether rodent activity is affected by the presence or absence of dead culms of the dwarf bamboo Sasa borealis, a species characterized by a 120-year cycle of large-scale flowering, seeding, and dying. We found that a relatively larger number of wood mice, Apodemus speciosus and Apodemus argenteus, were caught using Sherman live traps in areas with dead S. borealis culms than in areas lacking the culms, thereby indicating that S. borealis culms, even if dead and leafless, can function as shelters in which the mice can evade predation. However, in the years when A. speciosus was abundant, A. argenteus avoided areas inhabited by A. speciosus and was restricted to areas lacking dead culms, which were devoid of shelter. A feeding experiment using Castanea crenata acorns clearly revealed that a larger number of acorns were foraged by mice in areas containing dead culms. Moreover, in the area with dead culms, the mice preferentially removed sound acorns prior to taking acorns that had been vacated by infesting moth larvae. These findings indicate that the shelter function of dead culms enables mice to carefully select sound acorns, which are nutritionally more beneficial than those that have been infested by moth larvae. [ABSTRACT FROM AUTHOR]

Habitat type and habitat change are very important factors in the body condition of small mammals that inhabit them. The response can be positive, increasing, or the opposite, decreasing body condition. We analyzed outliers of the body condition indices (BCIs) of 12 species trapped in nine different habitats during 1980–2023 in Lithuania, a mid-latitude country. Mixed and fragmented habitats, as well as commensal habitats, could be considered the least suitable for small mammals, based on the highest proportions of underfit and low proportions of best-fit individuals. On the contrary, meadows and disturbed habitats (landfills and cormorant colonies) had the highest proportions of best-fit individuals, while the proportion of under-fit individuals was much lower than expected. We found outliers in the BCI in all species, except for the under-fit harvest mice (Micromys minutus), and in all habitats, though not numerous. The presence of the highest BCI in yellow-necked mice (Apodemus flavicollis) and bank voles (Clethrionomys glareolus) in the disturbed habitats studied and in house mice (Mus musculus) in commensal habitats may be related to the resources provided by these habitats. Our results demonstrate the feasibility of using retrospective small mammal morphometric data to analyze their relationship with habitat. [ABSTRACT FROM AUTHOR]

The relationship between the body condition of different small mammal species and the habitat they occupy is poorly analyzed. We analyzed the body condition index, BCI, of 18 small mammal species trapped in forest, shrub, wetland, meadow, riparian, mixed and fragmented, disturbed, agricultural, and commensal habitats of Lithuania during the span of 1980–2023. The composition of small mammal communities was habitat-dependent, being richest in meadows, with eighteen species, and poorest in riparian habitats, with nine species. A significant variation in the BCI with respect to habitat was observed in eight small mammal species (Sorex araneus, S. minutus, Apodemus agrarius, A. flavicollis, Clethrionomys glareolus, Alexandromys oeconomus, Microtus agrestis, and M. arvalis). The highest average BCI for most of these species was found in disturbed habitats, with S. minutus and M. arvalis showing the highest BCI in agricultural habitats. The lowest average BCI for most species was found in mixed habitats, while C. glareolus and M. arvalis exhibited the lowest BCI in shrub habitats. In general, species dominating certain habitats did not have the highest BCI. This is the first multi-species, multi-habitat study of body condition in small mammals at mid-latitudes. [ABSTRACT FROM AUTHOR]

Introduction: Blastocystis is one of the most critical intestinal protozoans in various hosts, including humans and mice. To determine the status of Blastocystis infection in wild rodents in China. Methods: A total of 344 faecal samples were collected from seven wild rodent species from three provinces, and the small subunit ribosomal RNA (SSU rRNA) genes of Blastocystis were amplified to determine their prevalence and subtypes. Results: Of the 344 samples, 54 (15.70%) were detected as Blastocystis-positive. The prevalence of Blastocystis was 26.14% (40/153), 7.95% (7/88), and 6.80% (7/103) in wild rodents from Hunan Province, Yunnan Province, and Guangxi Province, respectively. The prevalence of Blastocystis in different wild rodent species varied from 0.00% (0/13) in Mus musculus to 40.00% (2/5) in Rattus rattus sladeni. The prevalence of Blastocystis in samples from the lake beach area (27.40%, 40/146) was significantly higher than in those from the mountain (6.80%, 7/103) and field regions (7.37%, 7/95). The prevalence in different seasons was 26.14% in summer (40/153), 7.95% in autumn (7/88), and 6.80% in winter (7/103). Moreover, a total of two Blastocystis subtypes were identified in the investigated wild rodents, including ST4 and ST5. Discussion: The present study discovered the existence of Blastocystis infection in Rattus favipectus, Microtus fortis, Apodemus agrarius, Bandicota indica, Rattus rattus sladeni, and Rattus losea, expanding the host range of this parasite. The findings also demonstrate that wild rodents may be an important potential infection source for Blastocystis infection in humans and other animals. [ABSTRACT FROM AUTHOR]

Babesia is a tick-transmitted parasite that infects wild and domestic animals, causes babesiosis in humans, and is an increasing public health concern. Here, we investigated the prevalence and molecular characteristics of Babesia infections in the rodents in Southeastern Shanxi, China. Small rodents were captured, and the liver and spleen tissues were used for Babesia detection using traditional PCR and sequencing of the partial 18S rRNA gene. The analysis revealed that 27 of 252 small rodents were positive for Babesia, with an infection rate of 10.71%. The infection rates in different sexes and rodent tissues were not statistically different, but those in different rodent species, habitats, and sampling sites were statistically different. The highest risk of Babesia infection was observed in Niviventer confucianus captured from the forests in Huguan County. Forty-three sequences from 27 small rodents positive for Babesia infection were identified as Babesia microti, including 42 sequences from 26 N. confucianus, and one sequence from Apodemus agrarius. Phylogenetic analysis showed that all sequences were clustered together and had the closest genetic relationship with Babesia microti strains isolated from Rattus losea and N. confucianus in China, and belonged to the Kobe-type, which is pathogenic to humans. Compared to other Kobe-type strains based on the nearly complete 18S rRNA gene, the sequences obtained in this study showed the difference by 1–3 bp. Overall, a high prevalence of Babesia microti infection was observed in small rodents in Southeastern Shanxi, China, which could benefit us to take the implementation of relevant prevention and control measures in this area. [ABSTRACT FROM AUTHOR]

Many tree species adopt fast seed germination to escape the predation risk by rodents. Physical seed damage and the saliva of rodents on partially consumed seeds may act as cues for seeds to accelerate germination process. However, the impacts of these factors on seed germination rate and speed remain unclear. In this study, we investigated such impacts on the germination rate and speed (reversal of germination time) of four tree species (Quercus variabilis, Q. serrata, Q. acutissima, Q. glauca) after partial consumption by four rodent species (Leopoldamys edwards, Niviventer fulvescens, N. confucianus, Apodemus draco), through a series of experiments. We also examined how seed traits may affect the seed damage degree by rodents by analyzing the relationship between the germination rate and time of rodent‐damaged seed and the traits. We found that, artificially‐ and rodent‐damaged seeds exhibited a significantly higher seed germination rate and speed, compared to intact seeds. Also, the rodent saliva on seeds showed no significant effect on seed germination rate and speed. Furthermore, we observed significant positive correlations between several seed traits (including the seed mass, coat thickness, and protein content) and the seed germination rate and speed. These correlations are likely due to their beneficial traits countering seed damage by rodents. Overall, our results highlight the significant role of physical seed damage by rodents (rather than their saliva) in facilitating seed germination of tree species, and potential mutualism between rodents and trees. Additionally, our results may have some implications in forest restoration, such that intentionally sowing or dispersing slightly damaged seeds by humans or drones may increase the likelihood of successful seed regeneration. [ABSTRACT FROM AUTHOR]

Direct seeding is a revegetation method that can offer great advantages for forest restoration, but suffers the drawback of seed loss due to granivorous rodents. Thus, to make direct seeding a useful and scalable forest restoration method, we need to find ways to protect seeds against rodents. Scents produced by carnivorous or omnivorous animals that elicit a fear response on rodents are a promising group of substances that can be used to protect seeds and that have demonstrated effectiveness in a number of cases. Here, I test if human urine has a protective effect on Holm oak (Quercus ilex) acorns against predation by mice. Human urine would be much easier and cheaper to obtain than the urine of other animals, providing the possibility, if effective, to scale the application of a repellent substance. I set up a field experiment in an area with high wood mouse (Apodemus sylvaticus) abundance and used eight urine donors. Neither urine nor donor had any effect. Acorn removal was very fast and high, reaching 97.2% after 7 days. Video recording with camera traps showed that the wood mouse was the main predator, but the Eurasian jay also removed acorns. I conclude that human urine is not useful as a repellent against mice and suggest to focus efforts in finding other substances to repel seed predators. [ABSTRACT FROM AUTHOR]

Small mammals in the Horšianska dolina-Valley were researched first in 1984–86 and later in 2016–19. This paper seeks to identify and assess the species composition and dynamics of fleas (Siphonaptera) found in the valley on small mammals of Rodentia and Eulipotyphla and to compare findings from these two periods separated by thirty years. The results indicated deviations in small mammal and flea community similarity as well as in the small mammal indicator species for each habitat and flea indicator species for the small mammal species. A total 12 different species of small mammals were captured, and 12 flea species were collected. Eight flea species were detected in 1984–86 and ten species were found in 2016–19. In both periods A. penicilliger, C. assimilis, C. solutus, D. dasycnema, N. fasciatus were captured. The differences were that in the earlier period, the species uncovered were C. congener, P. bidentata, and P. soricis, while in the later period they were C. agyrtes, C. bisoctodentatus, M. turbidus, and R. integella. In the relationship between fleas and small mammals, C. solutus was the specific species for Apodemus flavicollis, while A. penicilliger and C. agyrtes were for Clethrionomys glareolus, and C. assimilis was for Microtus arvalis. [ABSTRACT FROM AUTHOR]

The thesis discusses the importance of sugar beet as a food supply for common voles and selected mice species (Apodemus spp.), which represent the most common rodent species in the stands of this crop. Sugar beet quality was determined using chemical analyses with a focus on the nitrogen content and comparison with other agricultural crops (spring and winter barley, winter wheat, alfalfa, rapeseed). The results showed a high proportion of nitrogen, especially in the leaves, and less in the tuber. The highest amount of nitrogen was found in alfalfa in the spring, while in the summer the proportion of nitrogen was lower than in alfalfa, comparable to winter rape and higher than in cereals. Based on literary sources, the article discusses the importance of beet leaves and tubers in the diet of mice and voles, as well as the importance of other food sources in sugar beet stands. In the common vole, the important food component is mainly the tubers, and less so the leaves. In the diet of mice, tubers and beet leaves were also recorded, but in a completely insignificant percentage. In sugar beet stands, mice maintain high numbers mainly by eating weed seeds and invertebrates. [ABSTRACT FROM AUTHOR]

Coronaviruses (CoVs), the largest positive-sense RNA viruses, have caused infections in both humans and animals. The cross-species transmission of CoVs poses a serious threat to public health. Rodents and bats, the two largest orders of mammals, serve as significant natural reservoirs for CoVs. It is important to monitor the CoVs carried by bats and rodents. In this study, we collected 410 fecal samples from bats and 74 intestinal samples from rats in Yunnan Province, China. Using RT-PCR, we identified one positive sample for alphacoronavirus (TC-14) from Rhinolophus sinicus (Chinese rufous horseshoe bat) and two positive samples for betacoronavirus (GS-53, GS-56) from Apodemus ilex (Rodentia: Muridae). We successfully characterized the complete genomes of TC-14 and GS-56. Phylogenetic analysis revealed that TC-14 clustered with bat CoV HKU2 and SADS-CoV, while GS-56 was closely related to rat CoV HKU24. The identification of positive selection sites and estimation of divergence dates further helped characterize the genetic evolution of TC-14 and GS-56. In summary, this research reveals the genetic evolution characteristics of TC-14 and GS-56, providing valuable references for the study of CoVs carried by bats and rodents in Yunnan Province. [ABSTRACT FROM AUTHOR]

The process of changes in the number and morphology of B chromosomes in the populations of mice (Apodemus peninsulae) in the northern region of the Pritelets taiga of the Altai Mountains over a 36-year period (1978‒2014) was traced. Three time phases were distinguished. From 1978 to 2002 (24 years)—a phase of steady growth of the number of B chromosomes, with a relatively uniform average increase of 1.4 chromosomes per decade (from 3.17 ± 0.2 to 6.5 ± 0.54); the phase of stabilization of the indicator when it consistently ranged between 6.3 and 6.9 (2002–2012), although the indicator was at least doubled compared to early 1980s (differences are significant); and the third period (2012‒2014) of the emerging trend of decrease in the number of supplementary chromosomes (differences are also significant). The change in the conditional mass index of B chromosomes (mB) also had similar dynamics, and it was at its maximum for the species during the period of stabilization. The dynamics of different morphotypes of B chromosomes showed an unequal contribution to the overall dynamics. The main contribution was made by large, medium-sized, and small metacentric B chromosomes. Micro-B chromosomes and acrocentrics were absent in the growth phase and appeared in the stabilization phase at the maximum of other indicators. [ABSTRACT FROM AUTHOR]

The results of studies of epididymal spermatozoa of three species of rodents (bank vole Clethrionomys glareolus, northern red-backed vole Cl. rutilus, and herb field mouse Sylvaemus uralensis) living under long-term exposure to atmospheric emissions from two large copper smelters in the Middle Urals are summarized (Middle Ural and Kirovgrad copper smelters). The impact of pollution (including at the individual level on the accumulation of Cu, Zn, Pb, and Cd in the liver) was assessed for indicators characterizing the quality of sperm from different aspects: morphology (proportion of cells with head and tail defects), motility (proportion of motile cells, velocity, and straightness of movement) and concentration. Sperm motility responds to pollution: in impact zones, the proportion of motile cells and their velocity were lower than in background zones. The occurrence of abnormal cells and sperm concentration were not statistically significantly different between impact and background zones. The reaction of sperm to chemical pollution is species-specific: voles react more strongly than the herb field mouse. The consistency of changes in sperm parameters (in the direction of their deterioration) in response to increased pollution was found only in the bank vole. Effect sizes for sperm parameters are much smaller compared to those for liver Cd accumulation and animal abundance. In general, the reaction of sperm to pollution turned out to be weak, none of the studied indicators can be a reliable marker of industrial pollution. [ABSTRACT FROM AUTHOR]

Forest understory complexity is important for many species, from large herbivores such as deer to small mammals such as mice and voles. For species that utilize the forest understory on a very small scale, it is often impractical to conduct correspondingly fine‐grained manual surveys of the understory, and thus few studies consider this small‐scale variation in understory complexity and instead work with average values on a larger scale. We explored the use of a mobile laser scanning derived understory complexity measure—understory roughness—to predict the capture probability of two representative small mammal species, the yellow‐necked mouse (Apodemus flavicollis) and the bank vole (Clethrionomys glareolus). We found a positive relationship between capture probability and understory roughness for both bank voles and yellow‐necked mice. Our results suggest that mobile laser scanning is a promising technology for measuring understory complexity in an ecologically meaningful way. [ABSTRACT FROM AUTHOR]

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Within-host interactions among coinfecting parasites can have major consequences for individual infection risk and disease severity. However, the impact of these within-host interactions on between-host parasite transmission, and the spatial scales over which they occur, remain unknown. We developed and apply a novel spatially explicit analysis to parasite infection data from a wild wood mouse (Apodemus sylvaticus) population. We previously demonstrated a strong within-host negative interaction between two wood mouse gastrointestinal parasites, the nematode Heligmosomoides polygyrus and the coccidian Eimeria hungaryensis, using drug-treatment experiments. Here, we show this negative within-host interaction can significantly alter the between-host transmission dynamics of E. hungaryensis, but only within spatially restricted neighbourhoods around each host. However, for the closely related species E. apionodes, which experiments show does not interact strongly with H. polygyrus, we did not find any effect on transmission over any spatial scale. Our results demonstrate that the effects of within-host coinfection interactions can ripple out beyond each host to alter the transmission dynamics of the parasites, but only over local scales that likely reflect the spatial dimension of transmission. Hence there may be knock-on consequences of drug treatments impacting the transmission of non-target parasites, altering infection risks even for non-treated individuals in the wider neighbourhood. [ABSTRACT FROM AUTHOR]

A total of 134 Apodemus samples, whose genetic diagnoses had been previously conducted, were morphologically examined from 39 localities in Northern Anatolia, Thrace, Gökçeada, Bozcaada, and Marmara Island. The variation boundaries of dental variations in the distribution areas of five Apodemus species (Apodemus flavicollis, Apodemus witherbyi, Apodemus sylvaticus, Apodemus uralensis, Apodemus mystacinus) included in the research were determined. The defining morphological characters of Apodemus species, which have a complex taxonomic status, and their variations according to regions were identified using samples that had undergone genetic diagnoses. It was determined whether geographical barriers such as the Marmara Sea, the Bosphorus and the Dardanelles, Melet River, Çoruh River and Kızılırmak separate populations of species from each other. It was found that the Kızılırmak likely caused a divergence in A. mystacinus samples, the Bosphorus and the Dardanelles likely caused a divergence in A. flavicollis species. However, it was not determined that the Melet River and Çoruh River caused a divergence within the species. Similarities and differences between island populations and mainland populations were identified in Apodemus species with distribution on islands. The differences observed in the Eastern-Western transition in Northern Anatolia were determined within the species and associated with habitats. [ABSTRACT FROM AUTHOR]

Simple Summary: In 2011, the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in the release of vast quantities of radioactive substances. In this study, we performed an ultrastructural analysis of the testis of the wild large Japanese field mouse (Apodemus speciosus), inhabiting the area near the ex-evacuation zones of the FDNPP and chronically exposed to various levels of low-dose-rate (LDR) radiation, to evaluate the effects of ionizing radiation on the male reproductive system and the possible consequences for future generations. Our results showed a preserved morphology of seminiferous tubules. However, ultrastructural changes, such as wide intercellular spaces, cytoplasmic vacuolization, vacuolated mitochondria, and increased lipid droplet clusters, were found, which could be linked to the mechanisms related to spermatogenesis. Long-term chronic LDR radiation exposure associated with the FDNPP accident had no pronounced adverse effect on spermatogenesis in A. speciosus, even if testis presented some ultrastructural changes. Our findings could be used in future studies to evaluate the effects of radiation on reproductive health in wild animals. Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, great attention has been paid to the impact of chronic low-dose-rate (LDR) radiation exposure on biological systems. The reproductive system is sensitive to radiation, with implications connected to infertility. We investigated the testis ultrastructure of the wild large Japanese field mouse (Apodemus speciosus) from three areas contaminated after the FDNPP accident, with different levels of LDR radiation (0.29 µSv/h, 5.11 µSv/h, and 11.80 µSv/h). Results showed good preservation of the seminiferous tubules, comparable to the unexposed animals (controls), except for some ultrastructural modifications. Increases in the numerical density of lipid droplet clusters in spermatogenic cells were found at high levels of LDR radiation, indicating an antioxidant activity rising due to radiation recovery. In all groups, wide intercellular spaces were found between spermatogenic cells, and cytoplasmic vacuolization increased at intermediate and high levels and vacuolated mitochondria at the high-level. However, these findings were also related to the physiological dynamics of spermatogenesis. In conclusion, the testes of A. speciosus exposed to LDR radiation associated with the FDNPP accident showed a normal spermatogenesis, with some ultrastructural changes. These outcomes may add information on the reproductive potential of mammals chronically exposed to LDR radiation. [ABSTRACT FROM AUTHOR]

Background: Many pathogens and parasites can infect multiple host species, and the competence of different hosts as pathogen reservoirs is key to understanding their epidemiology. Small mammals are important hosts for the instar stages of Ixodes ricinus ticks, the principal vector of Lyme disease in Europe. Small mammals also act as reservoirs of Borrelia afzelii, the most common genospecies of the Borrelia burgdorferi sensu lato (s.l.) spirochetes causing Lyme disease in Europe. However, we lack quantitative estimates on whether different small mammal species are equally suitable hosts for feeding I. ricinus and whether they show differences in pathogen transmission from host to tick. Methods: Here, we analysed the feeding success and prevalence of B. burgdorferi s.l. infections in 12,987 instar I. ricinus found on captured small mammals with known infection status in Norway (2018–2022). Results: We found that larvae were more likely to acquire a blood meal from common shrews (Sorex araneus, 46%) compared to bank voles (Myodes glareolus, 31%) and wood mice (Apodemus sylvaticus, 36%). Nymphs tended to be more likely to acquire a blood meal from wood mice (66%) compared to bank voles (54%). Common shrews harboured few nymphs (n=19). Furthermore, we found that larvae feeding on infected bank voles (11%) were more likely to be infected with B. burgdorferi s.l. than larvae on infected common shrews (7%) or wood mice (4%). Conclusions: Our study provides quantitative evidence of differences in suitability for the instar stages of I. ricinus across taxa of small mammals and highlights how even known small mammal host species can differ in their ability to feed ticks and infect larval ticks with the pathogen causing Lyme disease. [ABSTRACT FROM AUTHOR]

To investigate the effect of low temperature on body mass, thermogenic activity, and Uncoupling protein-1 (UCP1) content of brown adipose tissue (BAT) in Chevrier's field mouse (Apodemus chevrieri), 50 healthy adult mice with similar body mass were used in our experiment. They were divided into five groups of ten individuals as follows: a control group (0 d), where animals were maintained under 25 ± 1°C and a 12L:12D (light:dark, lights on 08:00) photoperiod; the other groups were maintained under 5 ± 1°C and a 12L:12D photoperiod for 7 d, 14 d, 21 d and 28 d, respectively. At the end of the experiment, the changes in body mass, resting metabolic rate (RMR), nonshivering thermogenesis (NST), BAT mass, mitochondrial protein (MP) content, cytochrome c oxidase (COX) activity, and UCP1 content were measured. The results showed that compared with the control group (0 d), the body mass of the cold acclimation groups decreased significantly. In contrast, RMR, NST, BAT mass, MP content, COX activity, and UCP1 content of the cold acclimation group increased significantly. After cold acclimation for 28 days, RMR increased by 89.4%, NST increased by 50.4%, BAT mass increased by 44.6%, and UCP1 content increased by 36.0%. The ratio of (NST − RMR)/RMR was 1.03 after seven days and then dropped to 0.59 on day 21, and remained at a steady level thereafter. Evidently, NST was significantly positively correlated with BAT mass and UCP1 content. The results indicated that under continuous cold exposure, A. chevrieri could take appropriate measures to reduce body mass, increase RMR, induce BAT tissue proliferation, and unregulated UCP1 expression, thereby enhancing BAT thermogenic activity to cope with a low-temperature environment. In the early stage of cold acclimation, NST was dominant in thermogenesis, but as time continued, it reduced. This may represent a unique energy adaptation strategy of small rodents originating from the north and spreading southward toward the Hengduan Mountain regions. [ABSTRACT FROM AUTHOR]

Rodents, including the striped field mouse (Apodemus agrarius), play vital roles in ecosystem functioning, with their gut microbiota contributing significantly to various ecological processes. Here, we investigated the structure and function of 94 wild A. agrarius individuals from 7 geographic populations (45°57′ N, 126°48′ E; 45°87′ N, 126°37′ E; 45°50′ N, 125°31′ E; 45°59′ N, 124°37′ E; 46°01′ N, 124°88′ E; 46°01′ N, 124°88′ E; 46°01′ N, 124°88′ E), revealing two distinct enterotypes (Type1 and Type2) for the first time. Each enterotype showed unique microbial diversity, functions, and assembly processes. Firmicutes and Bacteroidetes dominated, with a significant presence of Lactobacillus and Muribaculaceae. Functional analysis highlighted metabolic differences, with Type1 emphasizing nutrient processing and Type2 showing higher energy production capacity. The analysis of the neutral model and the null model revealed a mix of stochastic (drift and homogenizing dispersal) and deterministic processes (homogenous selection) that shape the assembly of the microbiota, with subtle differences in the assembly processes between the two enterotypes. Correlation analysis showed that elevation and BMI were associated with the phylogenetic turnover of microbial communities, suggesting that variations in these factors may influence the composition and diversity of the gut microbiota in A. agrarius. Our study sheds light on gut microbial dynamics in wild A. agrarius populations, highlighting the importance of considering ecological and physiological factors in understanding host–microbiota interactions. [ABSTRACT FROM AUTHOR]

As a part of research activities focused on rodent helminth fauna in Serbia, over the previous decade, we registered the presence of a species with zoonotic potential, Moniliformis moniliformis, an acanthocephalan (or spiny-headed worm) intestinal parasite that primarily infects rats, mice, and voles. The adult form of the species M. moniliformis was found in the small intestine of a single striped field mouse (Apodemus agrarius) from Cer Mountain, and two individuals of the yellow-necked mouse (Apodemus flavicollis) from the localities of Donji Milanovac and Senokos. Another species of Acanthocephala, reported in earlier studies of Spermophilus citellus in Serbia, is Macracanthorhynchus hirudinaceus, which also has zoonotic potential. Data on human infection with the acanthocephalans are scarce worldwide, including Serbia, but they should not be ignored.

Pollution of ecosystems by heavy metals such as mercury is currently a great concern. Mercury (Hg) can be released into the environment anthropogenically, but it is also naturally present in small quantities in all environmental compartments. Many different factors contribute to different rates of Hg deposition in animal bodies. The aim of this work is to describe how Hg concentrations in the bodies of small rodents change throughout the season at a site where massive anthropogenic pollution is not expected. Mice of the genus Apodemus were sampled during the whole year. Samples of blood, hair, liver, kidney, and brain were analyzed. Total Hg concentrations were measured by DMA-80. The mean Hg concentrations in examined organs were in the order hairs > kidney > liver > blood > brain, and their values decreased from 0.0500 to 0.0046 mg kg−1 dry weight. Males and females did not differ in contamination levels, but age-dependent differences in Hg concentrations were found. It was also identified how Hg concentrations in different organs correlate with each other. Different levels of seasonal variability were detected in Hg concentrations in blood, hair, and kidney. [ABSTRACT FROM AUTHOR]

In this paper, we investigated the relationship between the breeding parameters and food composition of the common barnowl (Tyto alba) comparing the outbreak and subsequent crash periods of the common vole (Microtus arvalis) as the barn owl’s main prey. For the analyses, data of 29 (2014 outbreak: 6, 2016 crash: 8; 2019 outbreak: 7, 2021 crash: 7) breeding pairs of barn owls were selected. First, we examined the differences between the breeding parameters (clutch size, number of hatchlings and fledglings), the main and alternative prey taxa (common vole and Apodemus genus), the two derived indices (trophic level index, Microtinae/Murinae ratio) between the given outbreaks and subsequent crashes as well as the cumulative data of the two demographic periods. In addition, we analysed the difference in rank-abundance distribution of prey composition comparing the outbreak and crash. We investigated the relationships between breeding parameters and demographic periods, the main and alternative prey taxa and the two derived indices using generalized linear mixed models (GLMM). The clutch size was significantly higher in both outbreaks than the crash periods, while the number of hatchlings and fledglings differed only between the second outbreak and crash period. Regarding the cumulative data of outbreaks and crashes, the values of all three breeding parameters were significantly higher in the outbreak period of the common vole. Our results highlighted the main prey role of common voles during the outbreak, as well as the importance of the Apodemus genus during the crash period. GLMM analysis supported that all three breeding parameters were positively determined by the ommon vole’s abundance in the diet of barn owls in outbreak and crash periods, while the reproductive output was positively influenced common by the frequency of the Apodemus genus as potential alternative prey in the crash period. [ABSTRACT FROM AUTHOR]

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The large Japanese field mouse (Apodemus speciosus) is endemic to the Japanese islands and Kunashir Island in Russia. Variability in the morphology of 722 molars was studied for the first time for the population of this species from Kunashir Island, which allowed us to identify seven new traits for the species. According to data obtained when studying modern and paleontological material (recent, Holocene, Late Pleistocene, Middle Pleistocene), mice of Kunashir Island lack some traits of molars previously described for the large Japanese field mouse from Honshu Island; at the same time, stabilization of the morphology was noted for the remaining traits. Varying frequency was demonstrated for the new traits. This can be caused either by the small number of founders or the passage of the Kunashir population through sharp declines in numbers. It is possible that a change in the frequency of some molar phenes in different historical epochs could be associated with the transition of mice to another type of feed following changes in the climate and the prevailing vegetation. [ABSTRACT FROM AUTHOR]

Using the method of group biomarking with rhodamine B, new data on migratory patterns (natal dispersal and breeding dispersal) of the pygmy wood mouse (Sylvaemus uralensis (Pallas 1811)) outside its home range were obtained by studying the long-distance locomotion of small mammals on the Eastern Urals Radiation Reserve (Chelyabinsk region, Southern Urals). Long-distance locomotion (1500 m) over 14 hours in the dark part of the day was registered for two yearling males for the first time, allowing for the possible speed of movement of S. uralensis to be estimated. Taking into account that the main activities of rodents occur during evening and morning twilight, the actual time could be considerably shorter. Both dispersers were under-yearling males of different functional status. One of them was a young animal captured during spring reproduction (May 2019) in the year of birth. The other male was young, captured before leaving in winter (October 2021) and not reproducing in the year of birth. Group biomarking by rhodamine B made it possible to estimate the night-time distance and the speed of movement of S. uralensis, also allowing an episode of external contamination by the biomarkers of transient specimens (October 2021) that visited the marking plot, but that did not touch the bait, to be revealed. Our results allow us to conclude that long-distance locomotion of individuals of different functional statuses beyond the home area is normal in S. uralensis. [ABSTRACT FROM AUTHOR]

The distribution of tick-borne encephalitis virus (TBEV) is expanding to Western European countries, including the Netherlands, but the contribution of different rodent species to the transmission of TBEV is poorly understood. We investigated whether two species of wild rodents native to the Netherlands, the wood mouse Apodemus sylvaticus and the yellow-necked mouse Apodemus flavicollis, differ in their relative susceptibility to experimental infection with TBEV. Wild-caught individuals were inoculated subcutaneously with the classical European subtype of TBEV (Neudoerfl) or with TBEV-NL, a genetically divergent TBEV strain from the Netherlands. Mice were euthanised and necropsied between 3 and 21 days post-inoculation. None of the mice showed clinical signs or died during the experimental period. Nevertheless, TBEV RNA was detected up to 21 days in the blood of both mouse species and TBEV was also isolated from the brain of some mice. Moreover, no differences in infection rates between virus strains and mouse species were found in blood, spleen, or liver samples. Our results suggest that the wood mouse and the yellow-necked mouse may equally contribute to the transmission cycle of TBEV in the Netherlands. Future experimental infection studies that include feeding ticks will help elucidate the relative importance of viraemic transmission in the epidemiology of TBEV. [ABSTRACT FROM AUTHOR]

The genetic and morphological variability of the southern form of the European chromosomal variety of the Ural field mouse Apodemus (Sylvaemus) uralensis (Pallas, 1811) in the North Caucasus was studied. The results of the sequence analysis of the cytochrome b gene fragment from nine geographical samples from the western, central, and eastern parts of the North Caucasus indicate a low degree of their genetic isolation with a relatively high diversity of haplotypes. Analysis of the morphological variability revealed high variety: three morphological groups were identified. Representatives of all three or two groups were found in the same geographical samples, but their distribution did not conform to the hypothesis of random occurrence. Based on indirect evidence, hypotheses about possible causes of the observed features of regional Ural field mouse biodiversity are formulated, which require verification in the course of future studies. In particular, we hypothesized that in the Late Pleistocene (130 000–11 700 cal years BP) there were several isolated populations in the region that could have been sources of species diversity in the Holocene. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the genetic diversity and relationships among Apodemus mystacinus lineages by analyzing mitochondrial Cytochrome b sequences. The study included samples from Iranand south east Turkey (Hakkari and Şırnak), in addition to previously studied populations. The results showed differences in the relationships among lineages and the structure of the phylogenetic tree compared to previous studies. A. m. mystacinus lineage, represented by samples from southwest Anatolia and Crete, was located at the base of the tree. The Iranian specimens were clustered with the southeastern specimens of Turkey in a separate lineage, indicating a possible refugium for A. mystacinus populations during glacial periods. The study also suggested that the expansion of A. mystacinus into Anatolia and neighboring regions during the Pleistocene facilitated its colonization of the Aegean islands. The differentiation between A. m. euxinus lineage and the south east Anatolia-Iran lineage may have resulted from the ancestral population in eastern Turkey diverging into two different lineages with one expanding its range towards the Black Sea and the other migrating towards the Zagros Mountains in Iran. These findings contribute to the understanding of the evolutionary history and phylogeography of A. mystacinus in its main range. [ABSTRACT FROM AUTHOR]

Background:Orientia tsutsugamushi is a zoonotic intracellular pathogen that requires parasitism in eukaryotic cells to reproduce. In recent years, tsutsugamushi disease reported in many places nationwide has crossed the Yangtze River, continuously, spreading to the North China. Now this phenomenon has aroused people's attention. Materials and Methods: In this study, meta-analysis was used to analyze the infection of rodents (vectors) in China, to clarify the transmission rule of O. tsutsugamushi. Results: This study included literature from six databases (PubMed, Web of Science, Science Direct, Wanfang, CNKI, and VIP). A total of 55 articles were included in the study from 610 retrieved articles. The total infection rate of O. tsutsugamushi in rodents was 5.5% (1206/20,620, 95% confidence interval [CI]: 0.0553–0.0617). The prevalence of O. tsutsugamushi in rodents before 2013 (7.73%, 95% CI: 4.11–12.37) was higher than after 2013 (2.11%, 95% CI: 0.64–4.41). O. tsutsugamushi spread among a variety of rodents, among which Rattus losea (13.3%, 95% CI: 4.33–26.26), Rattus tanezumi (5.69%, 95% CI: 1.37–12.72), and Apodemus agrarius (5.32%, 95% CI: 2.26–9.58) infection rate was higher. Kawasaki (8.32%, 95% CI: 1.42–20.17), Karp (7.36%, 95% CI: 2.62–14.22), Kato (2.54%, 95% CI: 0.08–8.28), and Gilliam (2.13%, 95% CI: 0.42–5.09) were the main prevalent genotypes in China. The prevalence of O. tsutsugamushi in rodents was seasonal, increasing gradually in summer (2.39%, 95% CI: 0.46–5.77), peaking in autumn (4.59%, 95% CI: 1.15–10.16), and then declining. The positive rate of immunofluorescence assay (25.07%, 95% CI: 8.44–46.88) was the highest among the detection methods, and it was statistically significant (p < 0.05). Based on the subgroup of geographical factors and climatic factors, the probability of O. tsutsugamushi infection in rodents was the highest when the temperature >19℃ (8.20%, 95% CI: 1.22–20.52), the altitude <100 millimeters (7.23%, 95% CI: 3.45–12.26), the precipitation >700 millimeters (12.22%, 95% CI: 6.45–19.50), and the humidity 60–70% (7.80%, 95% CI: 4.17–12.44). Conclusions: Studies have shown that rodents carrying O. tsutsugamushi are common. People should prevent and control rodents in life and monitor rodents carrying O. tsutsugamushi for a long time. [ABSTRACT FROM AUTHOR]

Past studies have revealed the benefits of rodent participation in the colonization process of oak species. Certain rodent species (Apodemus sylvaticus and Mus spretus) partially consume acorns, beginning at the basal part and preserving the embryo. Perea et al. (2011) and Yang and Yi (2012) found that during periods of abundance, the remains left after partial consumption continue to be present on the surface and are not transported to caches, given that they are perceived as leftovers. These remains, produced after several visits by the cache owner or by thieving conspecifics, also appear in the caches. If they are perceived as offal, they will not be attacked and may remain in these stores for longer periods, serving as resources for the cache builder. Our objective is to determine whether these remnants are perceived as offal by the rodent generating them or if the remains left by other rodents are considered offal. This is relevant in cases of theft, a common behavior of this species, if the thieving animals reject the remains. The results suggest that foreign remains and the rodents' own remains are not rejected, but rather, they are consumed in preference to intact acorns. The intact acorns remain in the cache for longer periods and have a greater opportunity to germinate and emerge. Rodents prefer to consume foreign remains first. This may be due to the fact that, in case of shortage, it is considered advantageous to finish the reserves of a potential competitor before depleting one's own reserves. Significance statement: Rodents participate in the acorn dissemination process by constructing surface stores (caches). The rodent species studied here partially consumes acorns, beginning with the basal part and preserving the embryo located at the apical end. These partially consumed acorn remains are considered offal and remain in the caches for longer periods, serving as reserves for the rodent. Our objective is to examine whether these acorn remains are viewed as offal by the rodents. We have found that, to the contrary, they are consumed before intact acorns. Intact acorns remain in the caches for longer periods, assuming the role of reserves and taking on a greater capacity to germinate. This species of rodent differentiates between its own remains and those of others, first consuming the foreign offal. Therefore, their own offal remains in the stores for longer periods and may potentially germinate if the embryo is preserved. This behavior has been demonstrated by this rodent species. [ABSTRACT FROM AUTHOR]

Phoresy is a passive transportation behavior where one organism (phoront) disperses to a new location by attaching to another organism. Pseudoscorpions are arthropod predators that mainly live in soil, subterranean habitats, and under tree bark. Some species also live in animal nests and engage in phoresy on small mammals, suggesting close associations with these animals. However, the relationship between phoretic pseudoscorpions and hosts as well as the ecological significance of phoresy remain largely unexplored. Here, to understand the function of phoresy of Megachernes ryugadensis, phoretic on small mammals, their phoretic behavior was investigated in a deciduous forest in northern Japan; individual-level dynamics of phoresy were examined by over 3-year mark-recapture surveys that concurrently marked the host and phoront; and host characteristics, such as sex and age class, were analyzed based on a 2-year small mammal trapping survey. The primary host species was the abundant Japanese wood mouse Apodemus speciosus. Out of 132 pseudoscorpions marked, 5 were recaptured approximately 1 month later. No pseudoscorpions were recaptured within the same census period (3–4 days) when they were marked, indicating that phoresy events last less than one night, and pseudoscorpions are unlikely to engage in phoresy again within a few weeks of their initial engagement. Furthermore, analysis of host characteristics revealed a tendency for female mice and adult individuals to have a higher probability of being hosts compared with males and subadults, respectively. Based on the findings in this and previous studies, the function of phoresy in this species is discussed. [ABSTRACT FROM AUTHOR]

Background: Wenzhou virus (WENV), a member of the Mammarenavirus genus in the Arenaviridae family, has been detected in wild rodents from eight provinces in China, including Zhejiang, Shandong, Hainan, Xinjiang, Hunan, Guangdong, Yunnan, and Jiangxi provinces, and some countries from Southeast Asia. The IgG-antibodies of WENV have been detected in both healthy populations and patients with unknown fever and respiratory symptoms. However, the potential harmfulness of WENV to humans has been underestimated due to mild symptoms after infection, similar to respiratory diseases. Thus, it is imperative to enhance the surveillance of WENV in wild rodents, particularly Rattus norvegicus, and continuously monitor its prevalence. Results: From 2017 to 2021, a total of 390 wild rodents were collected from six provinces in the eastern and southern coastal areas, containing nine species of rats. Samples of each tissue were collected, and PCR amplified for identification. Four R. norvegicus samples were detected to be WENV-positive. No genomic sequence of WENV was detected in Rattus flavipectus, Rattus losea, Suncus murinus, Apodemus agrarius, Mus musculus, Microtus fortis, Micromys minutus, and Niviventer niviventer from Jiangsu, Zhejiang, Fujian, Hainan, Guangdong and Guangxi provinces. Three genomic sequences were identified to be WENV by phylogenetic analysis. The full-length sequences of HAIKOU-40 were amplified in R. norvegicus from Hainan, which showed a close relationship to Wufeng/ WFS, sharing 84.5–89.4% homology at the nucleotide level and 91.6–98.9% homology at the amino acid level. Phylogenetic analysis revealed that HAIKOU-40 formed an Asia-specific cluster with all WENVs and Loie River mammarenavirus (LORV), provisionally named Asian ancestry. This cluster has diverged earlier from the remaining mammarenavirus. The sequences obtained in Xiamen, Fujian province showed more than 90% nucleotide identities with WENV, which may be a strain of WENV. Additionally, the sequence of Wuxi-87 which was a positive sequence detected in Wuxi, Jiangsu province exhibited 83% nucleotide identity with Lassa virus (LASV). Further efforts will be made to isolate and identify this virus strain, verify the relationship between Wuxi-87 and LASV, and confirm whether R. norvegicus is a new host of LASV. Conclusions: In this study, we conducted a systematic examination of the prevalence of WENV among rodents on the southeast coast of China. Additionally, we characterized the genome of a newly discovered WENV strain, that confirmed the role of R. norvegicus in the transmission of WENV. This highlights the importance of investigating the prevalence of WENV in both wild rodents and humans. [ABSTRACT FROM AUTHOR]

We investigated the presence and potential causes of sex bias in ectoparasite infestations in the yellow-necked mouse Apodemus flavicollis. We compared the natural tick and flea burdens of male and female mice in a temperate beech forest and assessed whether the observed differences were driven by host sex or body mass. We found that males were more heavily infested by ticks compared to female mice. However, this difference was driven by host body mass, and not sex itself. Host body mass positively correlated with flea loads, but there was no evidence of sex bias in flea abundance. In addition, the abundance of both ticks and fleas infesting yellow-necked mice changed over time, both seasonally (month to month) and annually (year to year). Our results underscore the importance of the sexual size dimorphism and the parasite taxon as the primary factors that influence the occurrence of sex-biased parasitism in small mammals. [ABSTRACT FROM AUTHOR]

Long-distance movements (LDMs) of small mammals (SMs) are complex phenomena that cover both dispersals and excursions occurring outside the home ranges of individuals. Owing to methodological difficulties, there are a lack of data on LDMs for SMs. In this study, we aimed to determine the factors that influence the LDMs of different mouse-sized rodents and shrews in the Ural taiga (Sverdlovsk region, Russia). We conducted a field experiment in a boreal forest using individual- (capture–marking–recapture [CMR]) and group- (biomarkers: tetracycline and rhodamine B) marking methods, in conjunction with additional feeding. The species, sex, maturity, plot ID, additional food supply, species abundance indices, individuals/100 trap-nights indices in the capture plot, and body weight of each animal were analyzed as predictors of LDMs. We identified 89 individuals from six species that moved at distances of 250, 350, and 500 m. LDMs varied with the particular species and its population abundance. Most of the observed movements were excursions and not dispersal events. Applying mathematical simulations to the obtained empirical data facilitated estimation of the intensity of the excursion activity for different species. We present the 1st excursion data on Sylvaemus uralensis (Pallas, 1811), Microtus arvalis (Pallas, 1778), and Sorex caecutiens (Laxmann, 1788). The detected excursion distance (250 m) for Myodes glareolus (Schreber, 1780) is the maximum excursion distance known for this species. We demonstrate that with comparable labor and time costs, the use of biomarkers makes it possible to detect many more LDMs than CMR allows. [ABSTRACT FROM AUTHOR]

In order to explore how the sympatric species of Eothenomys olitor, Apodemus chevrieri, Eothenomys miletus will adjust their thermogenic capacity to adapt to the environment under the background of global warming, as well as which species has stronger high-temperature adaptation ability. Body mass, liver and brown adipose tissue (BAT) mass and their protein contents under high-temperature conditions (30 ± 1°C, acclimation for 28 days) were measured in the present study. The results showed that all three kinds of animals in the warm acclimation group increased body mass and reduced thermogenic capacity, in which the indicators of thermogenesis for E. olitor had the smallest change range, and there were significant differences in body mass and thermogenic capacity among the three species. All of the above results suggested that the three sympatric rodents chosen to increase their body mass, reduced thermogenesis and energy consumption to adapt to the environment under high temperature conditions, which showed a phenomenon of convergent adaptation. Moreover, the change amplitude of the E. olitor was the smallest, indicating that high temperature has the least impact on its survival, indicating that E. olitor may had stronger adaptability under the conditions of global warming. [ABSTRACT FROM AUTHOR]

Background: Scatter-hoarding animals store food in multiple locations within their home range and rely on spatial memory for subsequent localization and retrieval. The relationship between memory and scatter-hoarding behavior has been widely demonstrated, but the association of gut microbiota with spatial memory and seed-hoarding behavior of animals remains unclear. Methods: In this study, by using enclosure behavior tests, memory tests including an object location test (OLT) and a novel object recognition test (NORT), and fecal microbiota transplantation (FMT) experiment, we evaluated the role of gut microbiota in affecting the memory and seed-hoarding behavior of rodents. According to their scatter-hoarding intensity, South China field mice (Apodemus draco) were divided into scatter-hoarding group (SG) and non-scatter-hoarding group (NG). Results: We found that the SG performed better than the NG in the NORT. FMT from SG donor mice altered the NG recipient mice's gut microbiota structure. Further tests demonstrated FMT from SG donor mice increased memory of NG recipient mice in laboratory tests and seed larder hoarding intensity of NG recipient mice in enclosures. Conclusion: Our results suggest gut microbiota could modulate the memory and seed-hoarding behavior of animals. [ABSTRACT FROM AUTHOR]

Mesocestoides canislagopodis is a common parasite of the arctic fox (Vulpes lagopus) in Iceland. In the past, household dogs (Canis familiaris) and cats (Felis catus) were also reported in Iceland to be infected. Recently, scolices of a non-maturing Mesocestoides sp. were detected in the intestines of the gyrfalcon (Falco rusticolus), and tetrathyridia were isolated in the body cavity of rock ptarmigan (Lagopus muta) and subsequently described. All stages were confirmed, using both morphological and molecular methods, to belong to the same species, M. canislagopodis. In the present study, post-mortem examination of wood mice (Apodemus sylvaticus), sampled in autumn 2014 on a farm in Northeast Iceland, revealed the presence of tetrathyridia in the peritoneal cavity and in the liver. Most tetrathyridia in the peritoneal cavity were free, but some were encapsulated in a thin connective tissue stroma and loosely attached to the inner organs. They appear as whitish, heart-shaped, flattened, unsegmented bodies with a slightly pointed posterior end. In the liver, tetrathyridia were seen as pale-tanned nodules embedded in the parenchyma. Comparative molecular analysis, both at the generic level (D1 domain LSU ribosomal DNA), and at the specific level (cytochrome c oxidase subunit I (cox1) and 12S mitochondrial DNA), revealed that the tetrathyridia belonged to M. canislagopodis. A. sylvaticus represents a new second intermediate host record in Iceland, and the first description of a rodent as intermediate host for this species, thus participating in the life cycle of the parasite. [ABSTRACT FROM AUTHOR]

Rodent pest species threaten many of the world’s resources, including those in agriculture, urban, and natural environments. Goodnature® A24 rat+stoat self-resetting traps (A24s) are used extensively for invasive rat control in several countries and environments, especially in island ecosystems. Unlike traditional single-set kill traps, A24s fire and reset up to 24 times per CO2 cartridge, and represent a nontoxic device for rodent pest control. Given the rapid rise in use of A24s as a management tool, our goal was to understand why A24s work in some cases and not others. To address this goal, we briefly review A24 literature, and then we: 1) introduce a special issue of A24 effectiveness and hazard studies, and 2) propose future research needs and recommended uses for A24s including a list of potentially susceptible rodent species for which further A24 testing is required. Most papers in the special issue focus on Rattus rattus control on islands in Hawaii and New Zealand. Additionally, A24 effectiveness was compared to toxic bait use against rats in California agricultural landscapes, and snap-traps against house mice (Mus musculus) in Colorado pens. Behavioral studies in this special issue demonstrated that both rats and mice repeatedly visit and pass by A24s much more frequently than they trigger A24s. Some large-scale trapping grids in Hawaiian forests reduced rat populations, but a few endangered birds were unintentionally killed by A24s, which stimulated research on bird excluder attachments for A24s. Understanding the duration of carcass persistence of rats and birds killed by A24s has helped trap users account for unobserved target and non- target kills. Future research may investigate A24 uses on rodent species other than Rattus, as the types of species potentially vulnerable to A24s range in size from mice (e.g., Apodemus, Mus, Peromyscus, Reithrodontomys; ≥ 14 g) to squirrels (e.g., Otospermophilus, Sciurus; 353–527 g). A24s can be used successfully to control rodent populations of some species in particular environments. Studies that compare A24s with alternative and synergistic rodent management methods will help determine the most effective and efficient rodent control methods that minimize non-target risks. [ABSTRACT FROM AUTHOR]

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We identified a novel lineage of lymphocytic choriomeningitis virus, tentatively named lineage V, in wood mice (Apodemus sylvaticus) from Germany. Wood mouse-derived lymphocytic choriomeningitis virus can be found across a substantially greater range than previously thought. Increased surveillance is needed to determine its geographic range and zoonotic potential. [ABSTRACT FROM AUTHOR]