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In the present work, a geometric morphologic study was carried out to compare the lower first molars of species belonging to the genera Allophaiomys, Terricola and Microtus and to explore the morphological variation within species. The examined teeth were recovered from nine Early and Middle Pleistocene sites, but recent material was also used in the study. We analysed the teeth of 733 Allophaiomys spp. 855 Terricola arvalidens, 339 Terricola hintoni and 625 recent Terricola subterraneus. Morphology and linear morphometric data of teeth were compared using canonical variate analysis and landmark analysis. The resulting morphological series reflect the phylogenetic relationships between species. We also tested the morphological changes observed in the fossil material with the separation times calculated from recent phylogenetic studies. Our results suggest that most phylogenetic changes can be traced by morphological analysis of this tooth. While the emergence of species belonging to the genera Terricola and Microtus is broadly consistent with the phylogenetic data, early colonisation of the genus Agricola was not morphologically detectable. The study of the genus Allophaiomys has revealed a palaeoecological difference between northern and southern Hungary during the mid-Pleistocene transition. Southern Hungary was covered with steppe, while northern Hungary was forested at that time. [ABSTRACT FROM AUTHOR]

The prairie vole (Microtus ochrogaster) has become a model organism for studying monogamy. A precise account of the phylogeography of this species should increase our understanding of the proximate mechanisms and ultimate factors underlying the observed geographic variation in monogamy. The prairie vole is widespread throughout the North American grasslands, and seven subspecies have been identified based on morphological variation, which suggests the development of genetic structure. However, a prior analysis of allelic diversity at nuclear microsatellite loci showed little geographic differentiation throughout the species’ range. To further address this inconsistency, we sequenced a segment of the mitochondrial cytochrome b locus in 34 individuals from separate geographic locations throughout the species’ range. The mitochondrial analysis revealed three widespread genetic clusters without clear geographic patterns. Thus, the results were consistent with the nuclear analysis by demonstrating low geographic differentiation, indicating likely incomplete lineage sorting in the species. Additionally, the observed patterns of mitochondrial and nuclear variation were not consistent with subspecies designations. Based on our analysis and prior genetic and morphological analyses, we suggest that a reevaluation of the subspecies designations in prairie voles is warranted, with the six contiguous subspecies of prairie voles being synonymized. [ABSTRACT FROM AUTHOR]

Voles and lemmings (subfamily Arvicolinae) remain some of the most difficult groups for disentangling phylogenetic relations owing to recent and very fast explosive radiation. The rapid radiation events are challenging for phylogenetic analysis and produce bushes of various shapes that are impossible to resolve with a straightforward approach using individual loci. Here using the quaddRAD-seq technique and transcriptomes, we tested whether data from the nuclear genome are consistent with trees inferred earlier from individual loci and from mitogenomes in topology and divergence dating. Both the transcriptome and quaddRAD-seq data convincingly place Arvicola as the earliest derivative within Arvicolini. This result is in agreement with the fossil record and conventional taxonomy. For the first time, whole-genome sequencing data resolved relations within the third radiation wave of the subfamily's taxa, namely the tribes Arvicolini, Lagurini, and Ellobiusini, which have formed polytomy in mitochondrial trees in earlier articles. This study indicates that divergence dating is highly dependent on the number and position of calibration points in a tree and on taxa sampling. In terms of phylogenetic inference, the position of nodes with insufficient taxa representation is the most susceptible to errors. [ABSTRACT FROM AUTHOR]

Interspecific and intraspecific interactions are integral components of antagonistic and mutualistic networks of all animal species. These interactions are affected by various factors, such as morphological, physiological, and genetic characteristics. However, the impact of personality traits on animal inter- and intraspecific interactions remains unclear. We investigated the role of different personality types (proactive and reactive) in Lasiopodomys brandtii. We examined both intraspecific interactions with Lasiopodomys brandtii and interspecific interactions with Kunming mice. We found that for intraspecific interactions, proactive individuals had higher numbers of contacts with opponents, spent more time in the vicinity of an opponent, and moved greater distances within the vicinity of an opponent. For interspecific interactions, proactive individuals had higher numbers of contacts with opponents than reactive individuals. These results suggest that proactive individuals, especially male voles, tend to occupy dominant positions in both intraspecific and interspecific relationships. Consequently, our study is meaningful in understanding how personality traits affect animal behavior, species niche differentiation, and community dynamics and local biodiversity. [ABSTRACT FROM AUTHOR]

Dietary flexibility allows animals to respond adaptively to food pulses in the environment. Here we document the novel emergence of widespread hunting of California voles and carnivorous feeding behavior by California ground squirrels. Over two months in the twelfth year of a long-term study on the squirrel population, we document 74 events of juvenile and adult ground squirrels of both sexes depredating, consuming, and/or competing over vole prey. Our video footage, photographic evidence, and direct observations of marked individual squirrels provide insights into the ecological circumstances favoring behavioral flexibility in foraging associated with a decadal peak in vole abundance. Digital video images related to the article are available at http://www.momo-p.com/showdetail-e.php?movieid=momo241126ob01a [ABSTRACT FROM AUTHOR]

In the evolution of proboscideans, the emergence of dwarf and semi-dwarf forms occurred repeatedly, on various territories and at various times, due to a lack of resources caused by geographic isolation on the islands and landscape isolation on the mainland. Despite a significant amount of information on the island forms of mammoths and elephants, the question of the association between a decrease in the body size and morphological changes in the dental system remains controversial. According to some data, the formation of dwarf forms was accompanied by a unidirectional decrease in the number of dental plates (NDP) of the tooth and thickening of the enamel. According to other data, changes in the dental system on the islands were mosaic in nature; that is, the NDP could decrease, remain unchanged, or even increase. Taking into account the importance of the NDP as a diagnostic tool for species identification of proboscidean taxa and the absence of a consensus on the stability of a trend towards a decrease in the NDP from tall continental ancestors to island dwarf descendants, we (1) summarize data on the finds of small teeth of mammoths from the Mammuthus genus with a reduced NDP in the localities in northern Eurasia, (2) present new radiocarbon dates, and (3) consider the NDP as a characteristic of developing dwarfism in continental mammoths. The study of small teeth of the last generation of M. primigenius from the coastal part of northeastern Siberia and a comparison with data from other regions demonstrated that the posterior sections of cheek teeth in mammoths are the most variable and represent a reduction complex. For woolly mammoth, the reduction primarily affects that part of the crown that became more complex by the gradual addition of the plates during phyletic evolution in the Middle–Late Pleistocene. A rapid loss of evolutionary achievements of the ancestral forms due to reduction is not a unique peculiarity of the woolly mammoth teeth, and was also traced in other mammals. The similarity of the reduction complexes of cheek teeth in proboscideans and rodents of the Arvicolinae subfamily was demonstrated; it can be traced by a decrease in the number of serially homologous elements of the crown: plates in proboscideans and pairs of prisms in arvicolines. A comparison of the NDP with the size of the M. primigenius teeth allowed us to make the assumption that a decrease in the NDP while maintaining other species-specific peculiarities of the tooth can be used as a criterion for separating semi-dwarf and small individuals of the woolly mammoth. The size of continental mammoths decreased most intensively during warmer intervals, when significant transformation of landscapes and a reduction in resource space occurred. [ABSTRACT FROM AUTHOR]

Simple Summary: We studied the differences in body size between males and females of 14 small mammal species in Lithuania. By measuring standard physical traits in voles, mice, and shrews from a large collection of long-term surveys, we updated information published 35 years ago and compared our results with data from other countries. Our results showed that males were larger than females in the yellow-necked mouse, root vole, and three other meadow voles, especially among adults. This pattern is consistent with Rensch's rule, which refers to how size differences between the sexes change with total body size. In contrast, females were larger than males in bank voles and four mouse species, although this was less consistent across age groups. Shrews and the smallest mouse species, the herb field mouse, showed no significant size differences between sexes. In some species, these size differences changed as the animals grew. We are adding data on less common species such as the sibling vole and northern birch mouse, which have not been studied extensively. Our research provides new baseline data for small mammals in the boreal mid-latitudes and serves as a foundation for future studies of how animals adapt to changing ecological conditions or climate change. We assessed the sexual size dimorphism (SSD), analyzing standard morphometric traits in juveniles, subadults, and adults, of 14 species of voles, mice, and shrews in Lithuania on the basis of long-term surveys, updating information published 35 years ago and in the context of data from other countries. ANOVA, t-tests, and a 5% threshold were used in the analyses. Male-biased SSD was observed in Apodemus flavicollis and Alexandromys oeconomus, which was subject to Rensch's rule, and in three other meadow vole species, with the strongest expression in adult individuals. Female-biased SSD was best expressed in Clethrionomys glareolus and was also identified in four mouse species, although patterns were less consistent across age groups. Shrews and the smallest mouse, Apodemus uralensis, exhibited monomorphic traits. The transition of dimorphism during postnatal development was observed in some species. We present an assessment of SSD in Microtus rossiaemeridionalis and Sicista betulina, the less common small mammals not analyzed in publications by other authors, and provide new baseline data for boreal mid-latitude small mammal species as a foundation for future studies on SSD and its adaptive significance under shifting ecological pressures or climate change. [ABSTRACT FROM AUTHOR]

Background: The mitochondrial genome serves as a pivotal molecular marker for delving into systematic relationships and adaptive mechanisms. The genus Eothenomys (Cricetidae: Arvicolinae) has consistently attracted attention due to its similar biological characteristics and the analysis of its mitochondrial genome offers a fresh perspective for comprehending the phylogeny and adaptation within Cricetidae. Methods: We sequenced and analyzed the entire mitochondrial genome of E. olitor and utilized the 13 PCGs derived from this genome to delineate the phylogenetic relationships within the Cricetidae and further evaluated the evolutionary rate of each PCG. Result: The findings revealed that the mitochondrial genome of E. olitor was 16,351 bp in length, including 13 PCGs with ATN initiation codons, 22 tRNAs, 2 rRNAs and 1 D-loop. Apart from the nad6 and 8 tRNAs positioned on the J-strand, the majority of the genetic elements were situated on the N-strand. The phylogenetic examination yielded a robust phylogenetic tree for Cricetidae, but the placement of some genera remained contentious, which needs more integrative and effective data. Among of them, E. olitor was a sister of E. chinensis and Eothenomys was monophyletic. Moreover, a selective analysis showed that evolutionary rates are significant differences among the 13 PCGs. Among these genes, atp8 a high evolutionary rate, while cox1 has a low. This research uncovered the mitochondrial genome analysis of E. olitor, offering valuable perspectives the phylogeny and adaptation within Cricetidae. [ABSTRACT FROM AUTHOR]

The quantity and timing of prey delivery affect the development of altricial young, can induce trade-offs in parental behavior, and ultimately influence fitness of the young. We investigated the dynamics of prey deliveries in a population of Swainson's Hawks (Buteo swainsoni) in northern California to better understand its temporal component. We installed 12 motion-triggered cameras in nests between 2013 and 2018, and documented 466 unique prey deliveries. Of those, 455 prey items were identifiable to at least class. Mammals made up the majority of prey in terms of number of deliveries (88.2%) and estimated biomass delivered to the nest (97.1%). Of those, pocket gophers (Thomomys spp.) and voles (Microtus spp.) together made up almost half of the deliveries and biomass. Most prey was delivered to the nest in midday (i.e., 1000–1459 H), suggesting these are important foraging hours for this population. However, afternoon air temperatures in the study area can be high and may require that nestlings be shaded, setting up a potential trade-off between foraging and protecting the nestlings' thermal homeostasis. Our study provides initial insight into the daily temporal dynamics of prey delivery for one of the latest-breeding raptors in North America. [ABSTRACT FROM AUTHOR]

The dominance of the voles Lagurodon arankae (Kretzoi, 1954) and Allophaiomys deucalion Kretzoi, 1969 in the Early Pleistocene small mammalian fauna from the main bone-bearing level of the Taurida cave (central Crimea) allows dating this faunal association to the beginning of the Calabrian (about 1.8–1.6 Ma), and correlating it to the Late Villafranchian and the MQ1 zone of the European mammal biochronological scale, the second half of the Psekupsian Faunal Assemblage, and the regional mammal zone MQR10 (Allophaiomys deucalion–Prolagurus ternopolitanus zone). The lower part of the cave deposits was found to contain components of the more ancient regional mammal zone MQR11 (Allophaiomys deucalion–Borsodia zone), which dates to the terminal Gelasian. Thus, the Early Pleistocene phase of the formation of the Taurida locality corresponds to the time interval of about 2.1–1.6 Ma. The cave deposits also yield remains of Middle Pleistocene small mammals dominated by the vole Microtus ex gr. arvalis (Pallas, 1778). The evolutionary level of these associations suggests an age of the mid Middle Pleistocene (about 0.5–0.3 Ma) and correlation with the regional mammal zone MQR3 (Arvicola mosbachensis–Lagurus transiens zone). [ABSTRACT FROM AUTHOR]

An exploration of the integration pattern of cheek teeth in Arvicolinae was conducted based on the sample representing 40 Recent genera/subgenera of voles. It employed the analysis of Pearson's correlations between dental units (entire crown outlines and individuated crown elements) described by geometric morphometric methods, and its results were interpreted as phyletic coordinations (in the sense of Schmalhausen). The lower tooth row was shown to be integrated somewhat weaker as compared to the upper one. The upper and lower tooth rows were in general the least intercorrelated, but M3 and m1 were rather highly correlated. Regarding intra-dental correlations of particular teeth, the least innerly integrated were m2 and m1. Each molar was shown to be subdivided, with some variants, into anterior and posterior portions. The lingual crown elements tended to be a little more correlated than the labial ones, while correlations between contralateral elements were the weakest. One of the most peculiar features of intra-dental correlations was shown to be the strong intercorrelations of all elements of m1 anteroconid that made it an autonomous unit within the lower toothrow. Regarding inter-dental correlations of crown elements, those between homologues were on average higher as compared to non-homologues. This feature of the overall integration pattern of the phyletic coordinations in arvicoline molars agreed in general with that shown previously for the ontogenetic correlations of cheek teeth in some unrelated mammals. Correlations between molar outlines themselves and phylogenetically independent contrasts calculated for the 1st MDS axis extracted from those outlines were shown to agree in some important details, with the former being on average weaker than the latter. [ABSTRACT FROM AUTHOR]

The known Plio-Pleistocene mammalian record, mainly represented by small mammals, and its biotic and geological context in the vast region of Eastern Turkey and Transcaucasus provides a sound base for regional biochronology. Recently obtained faunal associations and the main evolutionary lineages found in the region support direct correlations to the European (ELMA/MN/MQ) and the Eastern European (faunal complexes/MQR-MNR) biochronological systems. Important data on palynology, aquatic and terrestrial mollusks, and magnetostratigraphy integrate the reviewed material into a robust local biochronology. The range of standard biochrons of Early Pliocene through late Early Pleistocene and the regional Anatolian zones M-P are reliably detected. The Early Pleistocene time range (zone P) is refined based on rhizodont lagurines Borsodia and Euro-Asian larger voles Mimomys ex gr. pliocaenicus. The successive zone R for Early Pleistocene faunas with early rootless Microtini is proposed. [ABSTRACT FROM AUTHOR]

The subgenus Stenocranius contains two cryptic species: Lasiopodomys gregalis (subdivided into three allopatrically distributed and genetically well‐isolated lineages A, B, and C) and Lasiopodomys raddei. To identify karyotype characteristics of this poorly studied cryptic species complex, we used comparative cytogenetic analysis of 138 individuals from 41 localities in South Siberia and Mongolia. A detailed description of the L. raddei karyotype and of the L. gregalis lineage С karyotype is presented for the first time. The A chromosome complement of all examined narrow‐headed voles consisted of 2n = 36 and a fundamental number of autosomal arms (FNa) of 50. Between species, patterns of differential staining were similar, though additional C‐heterochromatic blocks were found in L. gregalis lineages; Ag‐positive nucleolar organizers and ribosomal DNA (rDNA) clusters are located on eight and nine acrocentric pairs, respectively. No B chromosomes (Bs) were found in the Early Pleistocene relic L. raddei, while one to five small heterochromatic acrocentric Bs were detected in all L. gregalis lineages; the number and frequency of Bs varied considerably within lineages, but no intraindividual variation was observed. In both species, telomeric repeats were visualized at termini of all chromosomes, including Bs. The number and localization of rDNA clusters on Bs varied among B‐carriers. Immunodetection of several meiotic proteins indicated that meio‐Bs are transcriptionally inactive and have a pattern of meiotic behavior similar to that of sex chromosomes (some homology of Bs to sex chromosomes is supposed). The nature, mechanisms of inheritance and stability of Bs in L. gregalis require further investigation. [ABSTRACT FROM AUTHOR]

The Duke of Bedford's vole (Proedromys bedfordi Thomas 1911) is distributed only at the border areas of the Sichuan and Gansu Provinces, China. In this study, the first complete mitochondrial genome of P. bedfordi is generated and characterized. The assembled genome is 16,262 base pairs in length and the base compositions present clearly the A-T bias (60.84%). Its genetic constitution and arrangement are consistent with the taxon of the voles, including 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 2 main non-coding regions, D-loop region and OL region. This mitochondrial genome will be a significant supplement for the genus Proedromys and whole mitogenome phylogenetic analysis provided insights into further evolutionary research of the subfamily Arvicolinae. [ABSTRACT FROM AUTHOR]

We explored whether canine assistance would significantly improve efficiency and effectiveness of snap-trapping for non-chemical management of voles. We expected dogs’ abilities to indicate real-time vole proximity could improve efficiency enough to render snap-trapping a feasible management tool at limited scales and where use of rodenticides is inappropriate. Timing was a critical component of our approach. Trapping commenced early January and thence every 14 days through mid-March, intended to directly reduce reproductive capacity by removing potential breeders before onset of breeding season and reducing early-season damage. We compared dog-assisted trapper efficiency and effectiveness to an “unassisted” human trapper working to scout and trap plots of the same size within the same field. We compared trap success (# voles killed per # traps set), efficiency (# voles killed per minutes spent searching and marking holes), and total search time invested. A late (March) pilot round of trapping in 2022 on 5 Willamette Valley farms (1 hazelnut, 2 dairy pastures, 2 vegetable) provided limited but promising results and allowed us to refine our approach. Canine-assisted (3 trained amateur teams) and unassisted − but expert − humans tied in trap success (0.41 voles/trap and 0.40 voles/trap, respectively), but average efficiency and total search time spent by canine-assisted (0.48 voles killed/search minute, 97 total search minutes) out-performed that of an unassisted human (0.29 voles killed/search minute, 232 total search minutes). The regional vole population crashed prior to our 2023 season, which added further challenge to our work on 6 pastures. When voles were sparse, canine-assisted teams spent less time searching, but unassisted humans caught more voles per trap set. Canine-assisted teams (2 experienced amateur, 1 professional team) caught 0.029 voles/traps set and 0.11 voles/search min over 593 total minutes compared to unassisted human capture rate of 0.047 voles/traps set and 0.049 voles/search min over a total of 1207 search minutes.

Previously known as Allophaiomys cf pliocaenicus, a new species of Pedomys is described from the early Pleistocene Java local fauna of South Dakota. Biostratigraphic correlations place the fauna between 2.0 and 1.29 Ma. Pedomys javaensis n. sp. is characterised by a first lower molar (m1) with three closed triangles (T) and a simple anteroconid (ACD) with a rare development of buccal re-entrant angle 5 defining an incipient T7. Connections between T5 and the ACD and T4–5 are broad, and the enamel is, on average, slightly positively differentiated. The M3 is simple, with distinct T5 and a relatively deep, posteriorly directed third lingual re-entrant angle. Twenty-two per cent of the Java m1s share morphological characters with Pedomys, prairie voles, suggesting that Pedomys originated from an early Pleistocene North American Allophaiomys-like ancestor. In the calculated ratios of m1 measurements, the new species lies morphologically between the Old World Allophaiomys deucalion and A. pliocaenicus. [ABSTRACT FROM AUTHOR]

Although cranial bones reliably identify the features of mammals, these traits can be affected by sex, population size and seasonality. This paper biometrically analyses the cranial features of the common vole. The research sample consisted of adult (n = 134), subadult (n = 57), of western Slovakia. Overall, software based on the highlighted marks measured 29 cranial features. Significant sexual dimorphism was observed for three features in adult individuals (width of the maxillary tooth row – right side "WMTRR", maximum height of the mandibula excluding coronoid process "AMdm" and coronoid height of the mandibula "AMd") and four features in subadults (length of the tooth row in the maxilla "LOSD", "WMTRR", length of the molar "LoM" and alveolar length of the lower molars "ALLM"). Results showed a significant positive relationship between body weight and cranial size in 18 of the 29 features. They also suggested a weak but significant positive effect of common vole abundance on cranium size (Chitty effect) likewise in 6 of the 29 features. In several cases, this effect affects, in addition to the abundance, the onset of sexual maturity of individuals. [ABSTRACT FROM AUTHOR]

The characterization of genes and biological functions underlying functional diversification and the formation of species is a major goal of evolutionary biology. In this study, we investigated the fast radiation of Microtus voles, one of the most speciose group of mammals, which shows strong genetic divergence despite few readily observable morphological differences. We produced an annotated reference genome for the common vole, Microtus arvalis , and resequenced the genomes of 10 different species and evolutionary lineages spanning the Microtus speciation continuum. Our full-genome sequences illustrate the recent and fast diversification of this group, and we identified genes in highly divergent genomic windows that have likely particular roles in their radiation. We found three biological functions enriched for highly divergent genes in most Microtus species and lineages: olfaction, immunity and metabolism. In particular, olfaction-related genes (mostly olfactory receptors and vomeronasal receptors) are fast evolving in all Microtus species indicating the exceptional importance of the olfactory system in the evolution of these rodents. Of note is e.g. the shared signature among vole species on Olfr1019 which has been associated with fear responses against predator odors in rodents. Our analyses provide a genome-wide basis for the further characterization of the ecological factors and processes of natural and sexual selection that have contributed to the fast radiation of Microtus voles. [ABSTRACT FROM AUTHOR]

BACKGROUND: The common vole has invaded the agroecosystems of northwestern Spain, where outbreaks cause important crop damage and management costs. Little is yet known about the factors causing or modulating vole fluctuations. Here, we used 11 years of vole abundance monitoring data in 40 sites to study density‐dependence and weather influence on vole dynamics. Our objective was to identify the population dynamics structure and determine whether there is direct or delayed density‐dependence. An evaluation of climatic variables followed, to determine whether they influenced vole population peaks. RESULTS: First‐ and second‐order outbreak dynamics were detected at 7 and 33 study sites, respectively, together with second‐order variability in periodicity (2–3 to 4–5‐year cycles). Vole population growth was explained by previous year abundance (mainly numbers in summer and spring) at 21 of the sites (52.5%), by weather variables at 11 sites (27.5%; precipitation or temperature in six and five sites, respectively), and by a combination of previous abundance and weather variables in eight sites (20%). CONCLUSIONS: We detected variability in vole spatiotemporal abundance dynamics, which differs in cyclicity and period. We also found regional variation in the relative importance of previous abundances and weather as factors modulating vole fluctuations. Most vole populations were cyclical, with variable periodicity across the region. Our study is a first step towards the development of predictive modeling, by disclosing relevant factors that might trigger vole outbreaks. It improves decision‐making processes within integrated management dealing with mitigation of the agricultural impacts caused by voles. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Spalacinae are an unusual component of the fossil record around the world with a limited geographical distribution. The revisited section of Afşar includes one of the richest collections of Spalacinae in Turkey. From Afşar 1, near the base of the section we recovered Pliospalax cf. macoveii while in Afşar 2, at the top of the section we distinguish the species P. tourkobouniensis. The current research includes the first record of the last-mentioned species outside of Europe. Both spalacines indicate a dry and open space environment and, in accordance with the Arvicolinae, suggest that Afşar 1 can be attributed to MN 15 while Afşar 2 is correlated to MN 16. [ABSTRACT FROM AUTHOR]

Changes in the blood systems of small rodents inhabiting for many generations the Chornobyl Exclusion Zone territories with a relatively low level of radionuclide pollution were studied. Animals’ calculated absorbed doses were in the low dose and dose rate ranges. Dual changes in the blood system were registered, damaging as well as reactive, and high variability of hematological and cytogenetic indicators was observed. Identified changes may be caused by the cumulative effects of chronic radiation exposure. [ABSTRACT FROM AUTHOR]

Animals may experience early negative (mechanical pain: being retrieved using an incisor by parents or attacked) or positive stimulation (being licked and groomed) that may affect emotional and social behaviors in adulthood. Whether positive tactile stimulation can reverse adverse consequences on emotional and social behaviors in adulthood resulting from chronic mechanical pain and underlying mechanisms remain unclear. This study used a tail‐pinching model during development to simulate mechanical pain experienced by pups in high‐social mandarin voles (Microtus mandarinus). Subsequently, brush‐like positive tactile stimuli were applied to the backs of the mandarin voles. Various behavioral tests were used to measure levels of anxiety, depression, and sociability. The results showed that early tail‐pinching delayed the eye opening of pups, increased levels of anxiety, reduced levels of sociality in male mandarin voles, and impaired social cognition in females during adulthood. Brushing on the back reversed some of these effects. While mandarin voles that were exposed to tail‐pinching during development were exposed to sub‐threshold variable stress as adults, they were more likely to show a stress‐induced increase of anxiety‐like behavior, reduction of sociability, and impairment of social cognition, displaying heightened susceptibility to stress, particularly in males. However, back‐brushing reversed some of these effects, implying that these adults display enhanced stress resilience. In addition, tail‐pinching reduced levels of serum oxytocin and increased corticosterone levels in serum, but back‐brushing reversed these effects. Overall, it was found that positive tactile stimulation reversed increases in anxiety and impairments of social behavior induced by negative stimulation in male mandarin voles via alteration of oxytocin and corticosterone levels. [ABSTRACT FROM AUTHOR]

In prion diseases, the species barrier limits the transmission of prions from one species to another. However, cross-species prion transmission is remarkably efficient in bank voles, and this phenomenon is mediated by the bank vole prion protein (BVPrP). The molecular determinants of BVPrP's ability to function as a universal prion acceptor remain incompletely defined. Building on our finding that cultured cells expressing BVPrP can replicate both mouse and hamster prion strains, we systematically identified key residues in BVPrP that permit cross-species prion replication. We found that residues N155 and N170 of BVPrP, which are absent in mouse PrP but present in hamster PrP, are critical for cross-species prion replication. Additionally, BVPrP residues V112, I139, and M205, which are absent in hamster PrP but present in mouse PrP, are also required to enable replication of both mouse and hamster prions. Unexpectedly, we found that residues E227 and S230 near the C-terminus of BVPrP severely restrict prion accumulation following cross-species prion challenge, suggesting that they may have evolved to counteract the inherent propensity of BVPrP to misfold. PrP variants with an enhanced ability to replicate both mouse and hamster prions displayed accelerated spontaneous aggregation kinetics in vitro. These findings suggest that BVPrP's unusual properties are governed by a key set of amino acids and that the enhanced misfolding propensity of BVPrP may enable cross-species prion replication. Author summary: The peculiar behavior of bank voles during prion transmission has attracted significant research interest. Whereas the species barrier restricts the transmission of prions between different species, bank voles are thought to be a universal prion acceptor. However, the molecular determinants of this phenomenon have remained elusive. In this study, we demonstrate that five specific residues in the bank vole prion protein are critical for facilitating cross-species prion transmission. Surprisingly, we found that two residues in the bank vole prion protein may have evolved to counteract its intrinsic misfolding propensity, as they severely restrict spontaneous aggregation as well as prion accumulation following cross-species prion challenge. These results provide new insight into the molecular basis of the species barrier for prion disease. [ABSTRACT FROM AUTHOR]

Mammalian herbivory represents a complex adaptation requiring evolutionary changes across all levels of biological organization, from molecules to morphology to behavior. Explaining the evolution of such complex traits represents a major challenge in biology, as it is simultaneously muddled and enlightened by a growing awareness of the crucial role of symbiotic associations in shaping organismal adaptations. The concept of hologenomic evolution includes the partnered unit of the holobiont, the host with its microbiome, as a selection unit that may undergo adaptation. Here, we test some of the assumptions underlying the concept of hologenomic evolution using a unique experimental evolution model: lines of the bank vole (Myodes [= Clethrionomys ] glareolus) selected for increased ability to cope with a low-quality herbivorous diet and unselected control lines. Results from a complex nature-nurture design, in which we combined cross-fostering between the selected and control lines with dietary treatment, showed that the herbivorous voles harbored a cecal microbiome with altered membership and structure and changed abundances of several phyla and genera regardless of the origin of their foster mothers. Although the differences were small, they were statistically significant and partially robust to changes in diet and housing conditions. Microbial characteristics also correlated with selection-related traits at the level of individual variation. Thus, the results support the hypothesis that selection on a host performance trait leads to genetic changes in the host that promote the maintenance of a beneficial microbiome. Such a result is consistent with some of the assumptions underlying the concept of hologenomic evolution. [ABSTRACT FROM AUTHOR]

The classification of rodent species can be challenging due to high morphological similarities observed among them. This problem is further increased in palaeontological systematics, where classification is traditionally based on the molar morphology. The subfamily Arvicolinae (Rodentia, Mammalia) is one of these rodent groups, whose classification being important for biostratigraphic and climatic studies of the Quaternary period is challenging. We present an application developed using the MatLab informatic algorithm, designed to classify the Arvicolinae species using Geometric Morphometrics (GMM) analyses of the first lower molar. Moreover, the application includes an option to automatically obtain the linear measurements that are commonly used for the identification of these species. This method shows a high degree of accuracy in the species classification, which is expected to increase as the reference database is further developed. This application can serve as an alternative tool for the classification of specimens with unclear morphologies. It can also be used to reduce the time required to manually obtain the linear indices necessary for their classification. [ABSTRACT FROM AUTHOR]

Simple Summary: It is common knowledge that Snowy Owls eat lemmings during the nesting season, and it is believed that lemming populations fluctuate dramatically over several years, often termed a cycle. When lemming populations reach high densities, Snowy Owls have a highly successful breeding season, producing numerous young per nest. This successful nesting results in large numbers of young Snowy Owls migrating south during their first winter. This movement, generally called an irruption migration, has been known for over a century, and stirs the admiration of the public. Indeed, each time an irruption migration happens, it is among the most popular wildlife viewing events in North America. Given this predator–prey relationship between Snowy Owls and lemmings, we were interested in quantifying how important lemmings were to Snowy Owls throughout their worldwide breeding range. Of the 15 studies we reviewed, 59,923 prey items were recorded. Lemmings were clearly the most important food source for breeding Snowy Owls, but voles were sometimes also important. Given the near obligate dependency on lemmings for breeding, one wonders how a changing climate will affect lemming populations and distribution, and consequently Snowy Owl breeding. And, will this affect the Snowy Owl breeding population, resulting in fewer young Snowy Owls migrating south during an irruption migration. We compared Snowy Owl feeding ecology from 15 breeding season studies throughout Nearctic and Palearctic circumpolar regions. We used raw data and information theory to assess the owls' feeding niche. Combined studies yielded 59,923 prey items, of which 59,585 were used for calculations. Overall, mean food niche breadth (FNB) was narrow: H′ = 1.95; R = 1.60, D = 0.526. In 10 of 15 studies, lemmings were > 71.8% of the owls' diet. In four studies, Lemmus was > 90% of the diet, and in three studies Dicrostonyx was >90% of the diet. In three other studies, Lemmus represented 71.8%, 73.8%, and 84.0% of the diet. In one study, Lemmus and Dicrostonyx were about equal: 49.1% and 47.5%. In the four remaining studies, Microtus and Clethrionomys voles were important. In contrast, of 5888 winter prey items from seven North American studies, the mean FNB (H′ = 4.61) was twice that of 15 breeding season scores, FNB (H' = 1.95). The Snowy Owl is primarily an obligate lemming predator for breeding. Changes to population ecology and distribution of lemmings due to climate change will have direct affects and effects on the Snowy Owls' reproductive output. The conservation of Snowy Owls is the conservation of lemmings. [ABSTRACT FROM AUTHOR]

Introduction: The mesolimbic reward system is associated with the promotion and rewarding benefits of social relationships. In the socially monogamous prairie vole (Microtus ochrogaster), the establishment of a pair bond can be displayed by a robust preference for a breeding partner and aggressive rejection of unfamiliar conspecifics. Mesolimbic dopamine signaling influences bondrelated behaviors within the vole through dopamine transmission and receptor activity in the nucleus accumbens. However, only one experiment has examined how the ventral tegmental area (VTA), a region that produces much of the foreand mid-brain dopamine, regulates these social behaviors. Specifically, inhibition of either glutamate or GABA neurons in the VTA during a brief courtship promoted a partner preference formation in male prairie voles. The VTA is a heterogeneous structure that contains dopamine, GABA, and glutamate neurons as well as receives a variety of projections including corticotropin-releasing factor (CRF) suggested to modulate dopamine release. Methods: We used pharmacological manipulation to examine how GABA and CRF signaling in the VTA modulate partner preference formation in male and female prairie voles. Specifically, we used a 3 h partner preference test, a social choice test, to assess the formation of a partner preference following an infused bicuculline and CRF during a 1 h cohabitation and muscimol and CP154526, a CRFR1 antagonist, during a 24 h cohabitation with an opposite-sex conspecific. Results: Our study demonstrated that bicuculline, a GABAA receptor antagonist, and CRF in the VTA promoted a partner preference, whereas low-dose muscimol, a GABAA receptor agonist, and CP154526, a CRFR1 antagonist, inhibited a partner preference in both male and female prairie voles. Conclusion: This study demonstrated that GABA and CRF inputs into the VTA is necessary for the formation of a partner preference in male and female prairie voles. [ABSTRACT FROM AUTHOR]

We investigate the acoustic structure of alarm calls in a highly social rodent, the Harting's vole (Microtus hartingi) and describe the phenomenon of collective shouting of bursts of alarm calls which could be produced in synchronized series. The alarm calls of Harting's voles were recorded using an automatic device from 10 different family groups, containing from 4 to 15 potential callers, released to outdoor enclosures. Natural predators and humans served as call-eliciting stimuli. We reveal acoustic differences between urgent alarm calls, evoked by close-vicinity predators and identified from recordings by their calls and by rustle noise from the caller's escape to burrow, and other alarm calls. We also reveal acoustic parameters between alarm calls produced in bursts and other alarm calls (produced in individual series or by a few non-synchronized callers). We discuss why the alarm calls of Harting's voles are unusually high-frequency (about 17 kHz on average in the maximum fundamental frequency) among other vole species producing high-frequency alarms. Adaptive significance of producing the collective synchronized bursts of alarm calls by Harting's voles remains unclear without direct observations of vocal vigilance in this species under natural conditions. [ABSTRACT FROM AUTHOR]

Tick‐borne encephalitis (TBE) virus is considered the medically most important arthropod‐borne virus in Europe. Although TBE is endemic throughout central Europe, ticks and rodents determine its maintenance in small, difficult‐to‐assess, natural foci. We investigated the interrelation between the population genetics of the main TBE virus (TBEV) vector tick (Ixodes ricinus), the most important reservoir host (Myodes glareolus, syn. Clethrionomys glareolus), and TBEV. Rodents and ticks were sampled on 15 sites within an exploratory study area, which has been screened regularly for TBEV occurrence in ticks for more than 10 years. On all 15 sites, ticks and bank voles were sampled, screened for TBEV presence via serology and RT‐PCR, and genetically examined. Moreover, TBEV isolates derived from these analyses were sequenced. In long‐term TBEV foci bank vole populations show extraordinary genetic constitutions, leading to a particular population structure, whereas ticks revealed a panmictic genetic structure overall sampling sites. Landscape genetics and habitat connectivity modeling (analysis of isolation by resistance) showed no landscape‐related barriers explaining the genetic structure of the bank vole populations. The results suggest that bank voles do not simply serve as TBEV reservoirs, but their genetic composition appears to have a significant influence on establishing and maintaining long‐term natural TBEV foci, whereas the genetic structure of TBEV's main vector I. ricinus does not play an important role in the sustainability of long‐term TBEV foci. A thorough investigation of how and to which extent TBEV and M. glareolus genetics are associated is needed to further unravel the underlying mechanisms. [ABSTRACT FROM AUTHOR]

The body condition index (BCI) values in small mammals are important in understanding their survival and reproduction. The upper values could be related to the Chitty effect (presence of very heavy individuals), while the minimum ones are little known. In this study, we analyzed extremes of BCI in 12 small mammal species, snap-trapped in Lithuania between 1980 and 2023, with respect to species, animal age, sex, and participation in reproduction. The proportion of small mammals with extreme body condition indices was negligible (1.33% with a BCI < 2 and 0.52% with a BCI > 5) when considering the total number of individuals processed (n = 27,073). When compared to the expected proportions, insectivores and herbivores were overrepresented, while granivores and omnivores were underrepresented among underfit animals. The proportions of granivores and insectivores were higher, while those of omnivores and herbivores were lower than expected in overfit animals. In several species, the proportions of age groups in underfit and overfit individuals differed from that expected. The male–female ratio was not expressed, with the exception of Sorex araneus. The highest proportion of overfit and absence of underfit individuals was found in Micromys minutus. The observation that individuals with the highest body mass are not among those with the highest BCI contributes to the interpretation of the Chitty effect. For the first time in mid-latitudes, we report individuals of very high body mass in three shrew species. [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]

Genetic admixture introduces new variants at relatively high frequencies, potentially aiding rapid responses to environmental changes. Here, we evaluate its role in adaptive variation related to climatic conditions in bank voles (Clethrionomys glareolus) in Britain, using whole-genome data. Our results reveal loci showing excess ancestry from one of the two postglacial colonist populations inconsistent with overall admixture patterns. Notably, loci associated with climate adaptation exhibit disproportionate amounts of excess ancestry, highlighting the impact of admixture between colonist populations on local adaptation. The results suggest strong and localized selection on climate-adaptive loci, as indicated by steep clines and/or shifted cline centres, during population replacement. A subset, including a haemoglobin gene, is associated with oxidative stress responses, underscoring a role of oxidative stress in local adaptation. Our study highlights the important contribution of admixture during secondary contact between populations from distinct climatic refugia enriching adaptive diversity. Understanding these dynamics is crucial for predicting future adaptive capacity to anthropogenic climate change. Genetic mixing among distinct bank vole populations in Britain has enhanced their adaptive diversity for climate adaptation, highlighting the importance of admixture in responding to environmental change. [ABSTRACT FROM AUTHOR]

Background: Knowledge about home range size is vital to understand social systems and population dynamics of small mammals, as well as dispersal and a species' landscape use. Home ranges have been mapped for some species of voles (subfamily Microtinae) but remain virtually unknown for many species, including the grey-sided vole Craseomys rufocanus. Results: A small pilot study was carried out in an inland valley of northern Norway, where six adult C. rufocanus were radio-tracked with one male and one female in each of the summers 2021–2023. Despite the small sample size, a large variation in home range size was found; males 2 294 − 36 887 m2 and females 1 728-7 392 m2 (100% MCP). Three of the voles tracked over a prolonged period of time showed a dynamic use and shifting of the range. Home range size and use was mostly related to reproduction. The male with the smallest range had probably not yet become reproductively active, whereas the male with the largest range was searching for females at a time when vole density was very low. The third male reduced his range when the reproductive season ended. For females the most important limitations were food, shelter and dependent young, those with young needed to return frequently and spend more time at the nest site. When the reproductive season ended, one female increased her range, perhaps exploring sites to overwinter. Conclusions: Home range use in this population appears to be more dynamic than has previously been reported for C. rufocanus. The large ranges of males most likely resulted from the search of reproductively active females, outside of the reproductive season male ranges approximated female ranges. Female ranges most likely were limited by the need to feed close to their nest with dependent young, being able to roam more freely when reproduction ended. [ABSTRACT FROM AUTHOR]

In this study, Taxonomic differences between Microtus guentheri and Microtus hartingi , which are similar in terms of external morphological features, were determined using linear morphometric, geometric morphometric, karyological and molecular analyses methods. Through classical morphometric (mean values) and geometric morphometric analyses of craniodental and mandible characters, influenced by various genetic, developmental, and functional processes, it was found that M. hartingi and M. guentheri exhibited notable differences in both mean linear measurements and shape. The Jackknife in classical morphometric analyses of samples, which underwent molecular and karyological species diagnoses, was higher than 88 % for each character. In geometric morphometric analyses, the Procrustes distance for shape follows the order Ventral < Dorsal < Mandible < M3

Taylor's law (TL) describes the relationship between the variance and mean of population density: log10(variance) ≈ log10(a) + b × log10(mean), a > 0. This study analyzed the temporal TL, for which mean and variance are calculated over time, separately for each population in a collection of populations, considering the effects of the parameters of the Gompertz model (a second‐order autoregressive time‐series model) and the skewness of the density frequency distribution. Time series of 162 populations of the gray‐sided vole in Hokkaido, Japan, spanning 23–31 years, satisfied the temporal TL: log10(variancej) ≈ 0.199 + 1.687 × log10(meanj). This model explained 62% of the variation of log10(variancej). An extended model with explanatory variables log10(meanj), the density‐dependent coefficient for 1‐year lag (α1,j), that for 2‐year lag (α2,j), the density‐independent variability (σj2), and the skewness (γj), explained 93.9% of the log10(variancej) variation. In the extended model, the coefficient of log10(meanj) was 1.949, close to the null value (b = 2) of the TL slope. The standardized partial regression coefficients indicated that density‐independent effects (σj2 and γj) dominated density‐dependent effects (α1,j and α2,j) apart from log10(meanj). The negative correlations observed between σj2 and log10(meanj), and between γj and log10(meanj), played an essential role in explaining the difference between the estimated slope of TL (b = 1.687) and the null slope (b = 2). The effects of those explanatory variables on log10(variancej) were interpreted based on the theory of a second‐order autoregressive time‐series model. [ABSTRACT FROM AUTHOR]

AbstractRodent pests pose significant impacts to agricultural systems and public health globally. Effective strategies for sustainable management while minimizing environmental impacts are crucial. To address the multifaceted nature of rodent impacts, well-coordinated initiatives are necessary to support control strategies, raise awareness among authorities, and inform the public. There is increasing global evidence of Working Groups delivering successful management of a range of natural resource management issues. We outline three case study working groups to tackle rodent pests: (1) National Mouse Group in Australia to manage mouse plague impacts, (2) Working Group Common Vole Management in Germany to manage common vole impacts, and (3) FREDON network for vole management in France. Each working group evolved independently, but all have remarkably similar structures, including monitoring, modelling/forecasting, regular stakeholder meetings (including producers, researchers, government agency staff and others), developing advice for management and identifying research priorities. The success of these working groups was related to: (1) broad stakeholder engagement (particularly farmers/producers), (2) dedicated funding to conduct direct research to inform control strategies, (3) maintained momentum through all phases of rodent population cycles, and (4) benefit for all stakeholders. As rodenticides are increasingly restricted, such working groups will become more important in the future, because stakeholder engagement is necessary to develop rodent management “toolboxes”. [ABSTRACT FROM AUTHOR]

Whether introduced into a completely novel habitat or slowly expanding their current range, the degree to which animals can efficiently explore and navigate new environments can be key to survival, ultimately determining population establishment and colonization success. We tested whether spatial orientation and exploratory behavior are associated with non-native spread in free-living bank voles (Myodes glareolus , N = 43) from a population accidentally introduced to Ireland a century ago. We measured spatial orientation and navigation in a radial arm maze, and behaviors associated to exploratory tendencies and risk-taking in repeated open-field tests, at the expansion edge and in the source population. Bank voles at the expansion edge re-visited unrewarded arms of the maze more, waited longer before leaving it, took longer to start exploring both the radial arm maze and the open field, and were more risk-averse compared to conspecifics in the source population. Taken together, results suggest that for this small mammal under heavy predation pressure, a careful and thorough exploration strategy might be favored when expanding into novel environments. [ABSTRACT FROM AUTHOR]

Juvenile situational experiences that animals are exposed to different environmental conditions have the potential to shape the developmental trajectory of individuals, influencing their personality traits, anxiety level, cognition, and memory. However, empirical evidence regarding these effects remains limited. In this study on male Brandt's voles (Lasiopodomys brandtii) undergoing weaning process, we examined the consequences of juvenile situational experiences on their behavioral development, involving daily exploration of newly introduced objects with a diverse array of materials, shapes, sizes, and colors. The results showed that (1) the situational experience improved spatial cognition and memory, as evidenced by significantly higher scores in both the recognition index during test period (RIB) and the discrimination index during test period (DI) compared to the control group; (2) no significant differences were observed in autonomic activity between the two groups, including total distance traveled, resting time, mean speed, maximum speed, and duration of slow and fast movements across the entire arena; (3) situational experience reduced anxiety levels, indicated by increased exploration of the center area, more transitions between zones, shorter latency to enter the center zone, prolonged resting time in the center area, and greater total time spent and distance moved in the center area; and (4) the situational experience group exhibited significantly higher individual personality scores compared to the control group. In conclusion, our results imply that juvenile situational experience exerts significant positive effects on spatial cognition and memory, anxious behavior, and personality development in L. brandtii. These insights offer novel perspectives on the long-term impacts of juvenile situational experiences on adulthood, with potential applications in addressing mental health and behavioral anomalies. Additionally, our study provides practical implications for animal management and environmental enrichment strategies. [ABSTRACT FROM AUTHOR]

Motherhood is a costly life‐history transition accompanied by behavioral and neural plasticity necessary for offspring care. Motherhood in the monogamous prairie vole is associated with decreased pair bond strength, suggesting a trade‐off between parental investment and pair bond maintenance. Neural mechanisms governing pair bonds and maternal bonds overlap, creating possible competition between the two. We measured mRNA expression of genes encoding receptors for oxytocin (oxtr), dopamine (d1r and d2r), mu‐opioids (oprm1a), and kappa‐opioids (oprk1a) within three brain areas processing salience of sociosensory cues (anterior cingulate cortex; ACC), pair bonding (nucleus accumbens; NAc), and maternal care (medial preoptic area; MPOA). We compared gene expression differences between pair bonded prairie voles that were never pregnant, pregnant (~day 16 of pregnancy), and recent mothers (day 3 of lactation). We found greater gene expression in the NAc (oxtr, d2r, oprm1a, and oprk1a) and MPOA (oxtr, d1r, d2r, oprm1a, and oprk1a) following the transition to motherhood. Expression for all five genes in the ACC was greatest for females that had been bonded for longer. Gene expression within each region was highly correlated, indicating that oxytocin, dopamine, and opioids comprise a complimentary gene network for social signaling. ACC‐NAc gene expression correlations indicated that being a mother (oxtr and d1r) or maintaining long‐term pair bonds (oprm1a) relies on the coordination of different signaling systems within the same circuit. Our study suggests the maternal brain undergoes changes that prepare females to face the trade‐off associated with increased emotional investment in offspring, while also maintaining a pair bond. [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]

Manipulation of host behaviour by parasites to enhance transmission to the next host is a fascinating phenomenon that has interested scientists since the 1970s. It has been proposed that infection with the cestode Echinococcus multilocularis produces an impairment of the antipredatory behaviour in the rodent intermediate host common vole, Microtus arvalis , which may facilitate transmission of the tapeworm to the canid final host. In this study, we observed the behaviour of infected common voles at 12 weeks post-infection, when protoscoleces production and maturation commonly occurs, in order to assess behavioural changes compared to uninfected controls, that might ease predation in the wild. Infected and uninfected voles were monitored for 24 h to observe their spontaneous activity. In addition, the next day, both infected and uninfected voles were subjected to 4 different behavioural tests: open field test, barrier test, platform test and air-puff test in a running wheel. No significant difference between uninfected and infected voles emerged during the behavioural tests. However, observation of spontaneous activity revealed that infected voles increased their feeding frequency and spent significantly more time above bedding even when not eating, compared to the uninfected controls. In the wild, these behavioural changes increase the animals exposure to predators, raising their chance of becoming prey. These findings are the first direct evidence consistent with behavioural manipulation by E. multilocularis on common voles. [ABSTRACT FROM AUTHOR]

Simple Summary: Bait-based fertility control could contribute to rodent pest management. Bait containing 4-vinylcyclohexene diepoxide (VCD) and triptolide (TP), registered as ContraPest®, was delivered to male common voles to assess the effects on reproductive structures and residues in the liver and testes. There were no effects or inconclusive effects for most reproductive parameters considered. However, there was an increase in sperm defects in voles treated for 14/28 days and fewer normal sperm cells in voles treated for 28 days. There were no TP residues in the testes, few and low TP residues and no VCD residues in the liver tissue. Treatments with VCD + TP seemed to have minor effects on male reproductive organs. Some rodent species cause significant damage to agriculture and forestry, and some can transmit pathogens to humans and livestock. The common vole (Microtus arvalis) is widespread in Europe, and its population outbreaks have resulted in massive crop loss. Bait-based fertility control could contribute to rodent pest management. Bait containing 4-vinylcyclohexene diepoxide (VCD) and triptolide (TP), registered as ContraPest®, was delivered to male common voles for 14 or 28 consecutive days. The effects on reproductive structures and residues in the liver and testes were assessed. There was no effect on testis weight, sperm viability, sperm motility and oxidative stress in sperm cells. Results regarding the mitochondrial membrane potential of sperm, DNA fragmentation and progressively motile sperm cells were inconclusive. However, there was an increase in morphological sperm defects in voles treated for 14/28 days and fewer normal sperm cells in voles treated for 28 days. There were no TP residues in the testes, few and low TP residues and no VCD residues in liver tissues, making considerable secondary exposure to non-target species unlikely. Treatments with VCD + TP seemed to have minor effects on the reproductive organs of males. Further studies should evaluate the effect of VCD + TP on females and on the reproductive success of common voles and other pest rodent species. [ABSTRACT FROM AUTHOR]

Very recently, an interesting phenomenon was described in the common vole; vole parents with similar locomotor ability produced significantly larger litters. Positive assortative mating is a tendency to prefer individuals with similar phenotypes. We tested whether this also applies to smell similarity. Odour preference was tested in a T-maze, where each female was presented with two male odours, i.e. shavings together with feces and urine from home boxes. After female preference was established, the female was either paired with a preferred male (chosen) or paired with a non-preferred male (opposite choice). For analysis of the relationship to odour preference, genotyping of major histocompatibility complex (MHC) Class II DRB was done using amplicon sequencing. In the set of 45 individuals from two populations, we recovered 38 nucleotide haplotypes (alleles). Similarity of alleles in parent pairs according to the indexes of Sørensen–Dice (S–D) and Jaccard were calculated. Values of these indexes in parental pairs with preferred males were significantly higher (more similar) than in not preferred. The number of offspring in parental pairs with preferred males were significantly higher than in not preferred males. However, there is no correlation between the mentioned indexes and the number of offspring. The relationship between the success of reproduction and alleles is not clear-cut, this may be influenced by the measure of similarity we used, or by something that we could not detect. [ABSTRACT FROM AUTHOR]

Most studies which deal with natural populations require a reliable and convenient way of age estimation. However, even rough aging of live individuals is often a real challenge. In this study, we develop a radiographic method for age estimation in Ellobius talpinus, a promising model species for population and behavioral ecology. Using portable X-ray equipment, we radiographed wild, non-sedated animals from the population that had been subjected to extensive mark-recaptures for 3 years. Two molar metrics strongly dependent on age and easy to measure on radiographs were selected: the lengths of the synclinal folds of the 1st upper and 1st lower molars. No influence of sex on the molar condition age dynamics was found. Discriminant function analysis based on molar condition and date of radiography in 86 animals of known age classes assigned X-ray images to three age classes (young of the year, yearlings, and 2 years or older) with an accuracy of 99%. Leave-one-out cross-validation yielded 97% correct assignments. All age estimates for 52 repeatedly radiographed individuals were consistent across images. The analysis of the repeated X-ray images obtained from the same animals showed that the 1st lower molars change faster in the first summer of life than later whereas the change rate of the 1st upper molars decreases little throughout life. We propose the X-ray technique as a useful alternative to direct skull and dental morphometry for age estimation of wild small mammals, saving the investigator's time and lives of animals. [ABSTRACT FROM AUTHOR]

Dozens of studies, most conducted in the last four decades, have implicated oxytocin, as well as vasopressin and their receptors, in processes that mediate selective sociality and the consequences of early experience. Oxytocin is critical for the capacity to experience emotional safety and healthy sexuality. Oxytocin also plays a central role in almost every aspect of physical and mental health, including the coordination of sociality and loving relationships with physiological reactions to challenges across the lifespan. Species, including prairie voles, that share with humans the capacity for selective social bonds have been a particularly rich source of insights into the behavioral importance of peptides. The purpose of this historical review is to describe the discovery of a central role for oxytocin in behavioral interactions associated with love, and in the capacity to use sociality to anticipate and cope with challenges across the lifespan - a process that here is called sociostasis.