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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]

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

Stress-induced illnesses, like major depression, are among the leading causes of disability across the world. Consequently, there is a dire need for the validation of translationally-suited animal models incorporating social stress to uncover the etiology of depression. Prairie voles (Microtus ochrogaster) are more translationally relevant than many other rodent models as they display monogamous social and bi-parental behaviors. Therefore, we evaluated whether a novel social defeat stress (SDS) model in male prairie voles induces depression-relevant behavioral outcomes. Adult sexually-naïve male prairie voles experienced SDS bouts from a conspecific pair-bonded male aggressor, 10 min per day for 10 consecutive days. Non-stressed controls (same-sex siblings) were housed in similar conditions but never experienced physical stress. Twenty-four h later, voles were evaluated in social interaction, sucrose preference, and Morris water maze tests – behavioral endpoints validated to assess social withdrawal, anhedonia-related behavior, and spatial memory performance, respectively. SDS-exposed voles displayed lower sociability and body weight, decreased preference for a sucrose solution, and impairment of spatial memory retrieval. Importantly, no differences in general locomotor activity were observed as a function of SDS exposure. This study does not include female voles in the experimental design. We found that repeated SDS exposure, in male prairie voles, results in a depression-relevant phenotype resembling an anhedonia-like outcome (per reductions in sucrose preference) along with social withdrawal and spatial memory impairment – highlighting that the prairie vole is a valuable model with potential to study the neurobiology of social stress-induced depression-related outcomes. • Social defeat stress decreases social behavior in adult male prairie voles • Social defeat stress decreases sucrose preference in adult male prairie voles • Social defeat stress impairs spatial memory in adult male prairie voles • Vole social defeat stress displays strong face validity as a model for the study of depression-related phenotypes [ABSTRACT FROM AUTHOR]

Numerous small mammal localities assigned to the beginning of the Late Middle Pleistocene (Holstein, Likhvin, Hoxne Interglacial) were discovered in Europe during the last years. The stratigraphical position of a number of these faunas and the regional differences are discussed in the paper. The new Likhvin small mammal locality Rybnaya Sloboda (Lower Kama basin, Volga basin, Russia) is the easternmost site of this age in Europe. The rich fauna was discovered in fluvial deposits of the 3rd terrace (III) of the Kama River; sediments that are covered by loess deposits with a series of paleosols. The Rybnaya Sloboda fauna includes 16 species of insectivores, lagomorphs and rodents. Remains of the archaic water vole Arvicola cantianus and the Middle Pleistocene steppe lemming Lagurus transiens dominate the fossils assemblage. The evolutional level of the Arvicolinae remains permits the assignment to the Gun'kovian small mammal assemblage and a correlation with the Likhvin Interglacial (MIS 11) (∼424–374 ka BP). The ecological features of the small mammal assemblage indicate a forest-steppe landscape in the lower Kama basin during MIS 11. The comparison with, and the analysis of numerous European Likhvin (= Holsteinian, = Hoxnian) small mammal faunas indicate a geographical biozonation that shows similarities with the biozonation reconstructed for the Eemian (= Mikulino, MIS 5e) Interglacial. [ABSTRACT FROM AUTHOR]

The construction of regional biochronological scales for the Pleistocene based on remains of small mammals is a systematic and successive process of accumulation of informative data with their subsequent presentation in the form of schemes and tables. The geological and palaeontological characteristics of reference sections are presented in detail. Faunal assemblages and developmental phases in associations of small mammals in the south of Eastern Europe are described based on the taxonomic composition of Pleistocene micromammal fauna. Ortho- and parastratigraphic taxa are identified and phylogenetic trees are constructed based on modifications of morphological traits in the evolution of separate species. A macroevolutionary biochronological scale has been compiled using several types of biochronozones. A phenozone-based microevolutionary biochronological scale has been established for the Quaternary of the south of Eastern Europe. These scales can be used to subdivide Quaternary deposits of this region by identifying biostratigraphic units and correlating them on local and regional scales. [ABSTRACT FROM AUTHOR]

In recent decades, human fathers across the globe have shown a substantial increase in their engagement in paternal caregiving behaviors. Despite the growing interest, the precise neurobiological mechanisms underlying caregiving behaviors in males remain unclear. Neurobiological studies conducted on rodents have advanced our understanding of the molecular, cellular, and circuit-level mechanisms. Typically, sexually naïve males exhibit aggression toward offspring, while fathers display parental behaviors. This drastic behavioral plasticity may be associated with changes in connections among specific regions or cell types. Recent studies have begun to describe this structural plasticity by comparing neural connections before and after fatherhood. In this Perspective , we summarize the findings from four well-studied rodent species, namely prairie voles, California mice, laboratory rats, and laboratory mice, with a view toward integrating past and current progress. We then review recent advances in the understanding of structural plasticity for parental behaviors. Finally, we discuss remaining questions that require further exploration to gain a deeper understanding of the neural mechanisms underlying paternal behaviors in males, including their possible implications for the human brain. • Although virgin males and fathers behave differently to young, underlying mechanisms are unclear. • Rodents contributed to the identification of brain regions and cell types for paternal behaviors. • Neural connections of a father's brain differ from those of virgin males. • Structural plasticity is a concept linking the behavioral shift and modification in the brain. [ABSTRACT FROM AUTHOR]

• Prairie vole peer and mate relationships are mediated by different mechanisms. • Dopamine D1 receptors are not upregulated when new peer relationships are formed. • D1 receptors are upregulated in solo-housed prairie voles. • D1 binding correlates with increased anti-social behaviors. • Prairie voles exhibit consistent social behaviors across test types. Prairie voles (Microtus ochrogaster) are socially monogamous rodents that form selective, long-lasting relationships with mates and with same-sex peers. It is unknown to what extent mechanisms supporting 'peer relationships' are similar to those involved in mate relationships. The formation of pair bonds is dependent on dopamine neurotransmission, whereas the formation of peer relationships is not, providing evidence of relationship type-specificity. The current study assessed endogenous structural changes in dopamine D1 receptor density in male and female voles across different social environments, including long-term same-sex partnerships, new same-sex partnerships, social isolation, and group housing. We also related dopamine D1 receptor density and social environment to behavior in social interaction and partner preference tests. Unlike prior findings in mate pairs, voles paired with new same-sex partners did not exhibit upregulated D1 binding in the nucleus accumbens (NAcc) relative to controls paired from weaning. This is consistent with differences in relationship type: D1 upregulation in pair bonds aids in maintaining exclusive relationships through selective aggression, and we found that formation of new peer relationships did not enhance aggression. Isolation led to increases in NAcc D1 binding, and even across socially housed voles, individuals with higher D1 binding exhibited increased social avoidance. These findings suggest that elevated D1 binding may be both a cause and a consequence of reduced prosociality. These results highlight the neural and behavioral consequences of different non-reproductive social environments and contribute to growing evidence that the mechanisms underlying reproductive and non-reproductive relationship formation are distinct. Elucidation of the latter is necessary to understand mechanisms underlying social behavior beyond a mating context. [ABSTRACT FROM AUTHOR]

• Medial habenular nucleus size correlates with impulsivity in wild rodents. • Bank voles show high impulsivity in the reaction time task. • Arc expression in mPFC is rare in bank voles and common in wood mice. Impulsivity is a personality trait of healthy individuals, but in extreme forms common in mental disorders. Previous behavioral testing of wild-caught bank voles and wood mice suggested impulsiveness in bank voles. Here, we compared behavioral performance of bank voles and wood mice in tests for response control in the IntelliCage. In the reaction time task, a test similar to the five-choice serial-reaction time task (5CSRTT), bank voles made more premature responses. Impulsivity in the reaction time task was associated with smaller medial habenular nucleus in bank voles. Additional tests revealed reduced behavioral flexibility in the self-paced flexibility task in bank voles, but equal spatial and reversal learning in the chaining/reversal task in both species. Expression of immediate early gene Arc after behavioral testing was low in medial prefrontal cortex, but high in hypothalamic supraoptic and paraventricular nucleus in bank voles. Wood mice showed the opposite pattern. Numbers of Arc-positive cells in the dorsal hippocampus were higher in bank voles than wood mice. Due to continuous behavioral testing (24/7), associations between behavioral performance and Arc were rare. Corticosterone measurements at the end of experiments suggested that IntelliCage testing did not elicit a stress response in these wild rodents. In summary, habenular size differences and altered activation of brain areas after testing might indicate differently balanced activations of cortico-limbic and cortico-hypothalamic circuits in bank voles compared to wood mice. Behavioral performance of bank voles suggest that these rodents could be a natural animal model for investigating impulsive and perseverative behaviors. [ABSTRACT FROM AUTHOR]

In this paper, first lower molars identified as Microtus arvalis from nine archaeological and palaeontological sites of the Italian Peninsula were analysed from a morphometric point of view, focusing on the development of the anterior part of the tooth. We used the data obtained to reveal possible patterns of evolution during the Late Pleistocene, as well as similarities and differences among the Italian samples and between Italian and European populations from the same timeframe. Factors such as the relative isolation provided by the Italian Peninsula, its milder climatic setting, intra-specific population dynamics, and the south-north displacement of Italian groups are taken into account to explain the environmental and historic causes of the peculiarities displayed by Italian samples of Microtus arvalis. [ABSTRACT FROM AUTHOR]

Well-dated Middle Palaeolithic sequences that lie beyond the limit of radiocarbon dating (i.e., >50,000 years ago) are critical for understanding the long-term palaeoecological changes that took place during Neandertal occupation of Europe and the Iberian Peninsula. Among the two pits excavated in Galería de las Estatuas site, GE (Sierra de Atapuerca, Burgos, Spain) represents such sequence, having been previously dated using a combination of single-grain optically stimulated luminescence (OSL) and U-series. This site is one of the few across Eurasia to have yielded both Neandertal remains and genetic evidence of Neandertal population replacements during marine isotope stage (MIS) 5 to the beginning of MIS 4 (120,000 to 70,000 years ago). Understanding the prevailing climatic and environmental conditions during the period of Neandertal occupation is therefore of great importance. Small mammal remains are one of the best proxies to interpret past environmental and climatic changes, and among these, the Arvicolinae species (Cricetidae, Rodentia) are particularly useful. Here we provide a revision of the small mammal associations at both Galería de las Estatuas pits undertaking detailed study of Arvicolinae species composition in both excavation pits. Additionally, we present new single-grain OSL dating results to refine the existing chronostratigraphic framework and better contextualise the past climatic changes inferred from the small mammal record. Our results indicate that the lower levels were formed in cold-temperate conditions, with a predominance of an open landscape and Atlantic-type climatic regime. Progressively upward through the sequences, we observe warmer and more humid conditions, with a stronger Mediterranean climate regime and increased development of forest areas, although still with a predominance of open meadows. Finally, both sedimentary sequences seem to end with a deterioration of these climatic conditions, and show a drier environment, dominated by open landscapes and a return to an Atlantic climatic regime. We conclude that at least two marked climatic changes can be identified at each pit (GE-I and GE-II), from MIS 5.4 through to the beginning of MIS 4, by studying the small mammal record together with OSL dating. • Review of the Arvicolinae association in the Galería de las Estatuas site. • Apporting news OSL dating to the Galeria de las Estatuas site. • Climatic variations during the Late Pleistocene (MIS 5-MIS 4) in the northern Iberian Peninsula. • Identify the transition between different substages of the MIS 5 through a continental record. [ABSTRACT FROM AUTHOR]

• The presence of temporary sources is key for species occurring in ephemeral patches. • An IBM explored the patch features affecting the emergence of temporary sources. • Synergistic effects among patch spatial attributes drove local source-sink status. • Short patch lifespans due to disturbance may jeopardize the emergence of sources. Understanding the demography of local populations within ephemeral habitat patches is crucial for effective local (site-based) conservation management in spatially and temporally heterogeneous environments. Evidence suggests that species persisting in networks of ephemeral patches often exhibit source-sink dynamics, where certain local populations act as temporary sources at some time between initial colonization and patch disappearance due to disturbance. Here we present an individual-based demographic model inspired by Cabrera voles (Microtus cabrerae) in dynamic agricultural mosaics to test the hypothesis that the emergence of a source local population within an ephemeral habitat patch is largely driven by the combined effects of the patch spatial attributes (size, internal quality and connectivity to other hypothetical patches) and the time to disturbance (i.e. the patch lifespan). We focused on two key emergent demographic metrics quantifying the source-sink status of local populations based on their self-sustainability and potential contribution to other patches. We used sensitivity analyses to estimate the strength of linear associations between these metrics and the patch spatial attributes, and to quantify the main and interaction effects across different patch lifespans since initial colonization. Our model revealed that considerable spatial and temporal variation may emerge in local populations' source-sink status based on differences in patch size, internal quality, connectivity, and lifespan. According to predictions, patch internal quality correlated positively with local population self-sustainability and potential contribution to other patches, though the strength of these relationships was mostly relevant only after about three vole generation times (ca. one year) since initial colonization, and only in combination with the positive effects of patch size and connectivity. Accordingly, results also supported the prediction that the emergence of a temporary source local population is conditional to the longevity of the habitat patch, with short patch lifespans (less than about three vole generation times) greatly limiting local population self-sustainability and potential contribution to other patches. While empirical testing is needed to confirm these findings, our study strengthens the view that local management efforts focusing on reducing or mitigating disturbance (e.g. severe droughts, human farming activities) at large and well-connected high-quality patches will likely promote the occurrence of temporary source local populations, which should be crucial for long-term species persistence over larger spatial scales. [ABSTRACT FROM AUTHOR]

Ambient temperatures have great impacts on thermoregulation of small mammals. Brown adipose tissue (BAT), an obligative thermogenic tissue for small mammals, is localized not only in the interscapular depot (iBAT), but also in supraclavicular, infra/subscapular, cervical, paravertebral, and periaortic depots. The iBAT is known for its cold-induced thermogenesis, however, less has been paid attention to the function of BAT at other sites. Here, we investigated the function of BAT at different sites of the body during cold acclimation in a small rodent species. As expected, Brandt's voles (Lasiopodomys brandtii) consumed more food and reduced the body mass gain when they were exposed to cold. The voles increased resting metabolic rate and maintained a relatively lower body temperature in the cold (36.5 ± 0.27 °C) compared to those in the warm condition (37.1 ± 0.36 °C). During cold acclimation, the uncoupling protein 1 (UCP1) increased in aBAT (axillary), cBAT (anterior cervical), iBAT (interscapular), nBAT (supraclavicular), and sBAT (suprascapular). The levels of proliferating cell nuclear antigen (PCNA), a marker for cell proliferation, were higher in cBAT and iBAT in the cold than in the warm group. The pAMPK/AMPK and pCREB/CREB were increased in cBAT and iBAT during cold acclimation, respectively. These data indicate that these different sites of BAT play the cold-induced thermogenic function for small mammals. The schematic diagram illustrates cold-stimulated BAT thermogenesis at different sites of the body in Brandt's voles (Lasiopodomys brandtii). During cold acclimation, the levels of UCP1, PCNA, and pCREB/CREB increased in iBAT; UCP1, PGC1α, and pAMPK/AMPK increased in cBAT; UCP1 and PCNA increased in aBAT; UCP1 increased in nBAT and sBAT; and PGC1α increased in chBAT. These data indicate that these different sites of BAT play the cold-induced thermogenic function. As a result, the voles increased the metabolic rate and food intake, but reduced body temperature and body mass gain to defense cold. aBAT, axillary brown adipose tissue; cBAT, anterior cervical BAT; chBAT, cheek BAT; iBAT, interscapular BAT; nBAT, supraclavicular BAT; sBAT, supraspinal BAT; PCNA, proliferating cell nuclear antigen; PGC1α, peroxisome proliferator-activated receptor gamma coactivator 1α; pAMPK/AMPK, phosphorylated AMP-activated protein kinase/AMP-activated protein kinase; pCREB/CREB, phosphorylated cAMP response element-binding brotein/cAMP response element-binding protein; UCP1, uncoupling protein 1. [Display omitted] • The uncoupling protein 1 (UCP1) increased in brown adipose tissue (BAT) at different sites of body during cold acclimation. • Cell proliferation increased in anterior cervical BAT (cBAT) and interscapular BAT (iBAT) during cold acclimation. • The AMPK and PKA signaling pathways were activated in cBAT and iBAT during cold acclimation • The different sites of BAT play the cold-induced thermogenic function. [ABSTRACT FROM AUTHOR]

• Three-day AMPH injections impaired social recognition in female voles. • AMPH treatment also altered depressive-like behavior in female voles. • AMPH treatment decreased neuronal and CRH neuron activation in the DG and PVN. • AMPH treatment also decreased TH neuron activation but did not affect OT neurons in the PVN. Previous studies have shown that 3-day d-amphetamine (AMPH) treatment effectively induced conditioned place preferences (CPP) and impaired pair bonding behaviors in prairie voles (Microtus ochrogaster). Using this established animal model and treatment regimen, we examined the effects of the demonstrated threshold rewarding dose of AMPH on various behaviors and their potential underlying neurochemical systems in the brain of female prairie voles. Our data show that 3-day AMPH injections (0.2 mg/kg/day) impaired social recognition and decreased depressive-like behavior in females without affecting their locomotion and anxiety-like behaviors. AMPH treatment also decreased neuronal activation indicated by the labeling of the early growth response protein 1 (Egr-1) as well as the number of neurons double-labeled for Egr-1 and corticotrophin-releasing hormone (CRH) in the dentate gyrus (DG) of the hippocampus and paraventricular nucleus of the hypothalamus (PVN) in the brain. Further, AMPH treatment decreased the number of neurons double-labeled for Egr-1 and tyrosine hydroxylase (TH) but did not affect oxytocinergic neurons in the PVN or cell proliferation and neurogenesis markers in the DG. These data not only demonstrate potential roles of the brain CRH and dopamine systems in mediating disrupted social recognition and depressive-like behaviors by AMPH in female prairie voles, but also further confirm the utility of the prairie vole model for studying interactions between psychostimulants and social behaviors. [ABSTRACT FROM AUTHOR]

In monogamous species, pair bonding leads to striking changes in social behavior and neural circuitry. We outline the cognitive building blocks of monogamous pair bonding in prairie voles (Microtus ochrogaster), as well as opportunities afforded by the species to investigate diverse mechanisms underlying social experience-dependent plasticity and gain insights into the neurobiology of complex social behavior more generally. [ABSTRACT FROM AUTHOR]

The ability to form enduring social bonds is characteristic of human nature, and impairments in social affiliation are central features of severe neuropsychiatric disorders including autism spectrum disorder and schizophrenia. Owing to its ability to form long-term pair-bonds, the socially monogamous prairie vole has emerged as an excellent model to study the neurobiology of social attachment. Despite the enduring nature of the bond, however, surprisingly few genes have been implicated in the pair-bonding process in either sex. Male and female prairie voles (Microtus ochrogaster) were cohabitated with an opposite-sex partner for 24 hours or 3 weeks, and transcriptomic regulations in the nucleus accumbens were measured by RNA sequencing. We found sex-specific response patterns despite similar behavioral indicators of pair-bond establishment. Indeed, 24 hours of cohabitation with an opposite-sex partner induced widespread transcriptomic changes that remained sustained to some extent in females after 3 weeks but returned to baseline before a second set of regulations in males. This led to a highly sexually biased nucleus accumbens transcriptome at 3 weeks related to processes such as neurotransmission, protein turnover, and DNA transcription. In particular, we found sex-specific alterations of mitochondrial dynamics following cohabitation, with a shift toward fission in males. In addition to identifying the genes, networks, and pathways involved in the pair-bonding process in the nucleus accumbens, our work illustrates the vast extent of sex differences in the molecular mechanisms underlying pair-bonding in prairie voles and paves the way to further our understanding of the complex social bonding process. [ABSTRACT FROM AUTHOR]

This article presents data on the enamel characteristics (thickness, enamel differentiation coefficient (SDQ)) of the first lower molars of the European water vole (based on the conditional groups "juvenile" and "adult") from fossil and modern samples from the Perm Pre-Urals (Russia). Among the "adult" group teeth, samples from the Eemian (Mikulino) interglacial deposits had the highest mean SDQ values (91.5–94.8), while samples from the end of the Bryansk Interstadial, the Late Glacial, the Early Holocene deposits had the lowest (76.3–84.9). [ABSTRACT FROM AUTHOR]

[Display omitted] • Eimeria of 2 ecologically similar rodent groups form a complex system of genetic lineages with different host specificities. • The lineages retained their host specificities while spreading across large geographic areas. • The genetic structure is only partially reflected by morphological traits. Interplay between conserved host specificity and occasional host switches is an important process determining the evolution of host-parasite systems. Here, we address the dynamics of host switches at the population level in rodent-associated Eimeria. Focusing mainly on two ecologically similar host groups, Murinae and Arvicolinae, we show that the Eimeria infecting those hosts form a complex system of many genetic lineages with different host specificities. The broad geographic distribution of lineages indicates that they are well-established genetic forms which retained their host specificities while spreading across large geographic areas. We also demonstrate that genetic structure is only partially reflected by morphological traits. [ABSTRACT FROM AUTHOR]

• Genomic characterization of viruses is essential to understand their pathophysiology. • We have designed a targeted hybrid-capture panel encompassing all Orthohantaviruses. • We have sequenced the first complete Swedish wild-type Puumala virus genomes. • Puumala virus from humans and bank voles revealed a close phylogenetic relationship. • This method could be used for diagnostic purposes and Orthohantavirus surveillance. Orthohantaviruses, transmitted primarily by rodents, cause hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus pulmonary syndrome in the Americas. These viruses, with documented human-to-human transmission, exhibit a wide case-fatality rate, 0.5–40 %, depending on the virus species, and no vaccine or effective treatment for severe Orthohantavirus infections exists. In Europe, the Puumala virus (PUUV), carried by the bank vole Myodes glareolus , causes a milder form of HFRS. Despite the reliance on serology and PCR for diagnosis, the three genomic segments of Swedish wild-type PUUV have yet to be completely sequenced. We have developed a targeted hybrid-capture method aimed at comprehensive genomic sequencing of wild-type PUUV isolates and the identification of other Orthohantaviruses. Our custom-designed panel includes >11,200 probes covering the entire Orthohantavirus genus. Using this panel, we sequenced complete viral genomes from bank vole lung tissue, human plasma samples, and cell-cultured reference strains. Analysis revealed that Swedish PUUV isolates belong to the Northern Scandinavian lineage, with nucleotide diversity ranging from 2.8 % to 3.7 % among them. Notably, no significant genotypic differences were observed between the viral sequences from reservoirs and human cases except in the nonstructural protein. Despite the high endemicity of PUUV in Northern Sweden, these are the first complete Swedish wild-type PUUV genomes and substantially increase our understanding of PUUV evolution and epidemiology. The panel's sensitivity enables genomic sequencing of human samples with viral RNA levels reflecting the natural progression of infection and underscores our panel's diagnostic value, and could help to uncover novel Orthohantavirus transmission routes. [ABSTRACT FROM AUTHOR]

The prairie vole (Microtus ochrogaster) is a rodent species that has been used extensively to study biological aspects of human social bonding. Nevertheless, this species has not been studied in the context of modeling social deficits characteristic of schizophrenia. Building on studies in rodents that show that sub-chronic administration of an NMDA receptor antagonist induces persistent behavioral and neurological characteristics of schizophrenia, we administered MK-801 (0.2 mg/kg, daily, for 7 days) or physiological saline to young adult (45 days old) virgin male voles. At 69 days of age, we paired these males with virgin females. 24 h later, we assessed the males' social investigation of each female across the first 5 min of a three-hour preference test, and side-by-side contact with each female during the last hour of the test. Unlike saline-treated males, MK-801-treated males did not preferentially investigate the unfamiliar female, indicating a deficit in social memory. Although males of both groups preferentially spent time with their female partner, regression analysis revealed that deficits in social memory predicted lower partner preference in MK-801-treated males. We interpret these results in the context of recent studies of the natural history of the prairie vole as well as in the context of cognitive deficits in schizophrenia and propose that the social component of episodic memory might influence an individual's capacity to form and maintain long-term social bonds. [ABSTRACT FROM AUTHOR]

To find out whether a social subterranean rodent—the northern mole vole (Ellobius talpinus)—hibernates in winter, nine individuals from Southern Siberia were captured in late autumn and implanted with loggers [that constantly recorded body temperature (T b) and locomotor activity] and then released. Eight of them were recaptured the following spring. From October to April, the animals' T b never dropped below 33 °C, although cosinor analysis revealed a decrease in mesor values and in the amplitude of daily fluctuations of T b and activity in winter months. Spectral density of circadian rhythms of both indexes also diminished in winter. The magnitude of T b and fluctuations of activity differed between the two studied familial groups, probably due to their unequal numbers of individuals, which could affect the total heat production. The levels and patterns of temperature and activity fluctuations observed in winter rule out the possibility of hibernation in this species. • In none of 9 studied mole voles body temperature dropped below 33 °C throughout the winter. • All the mole voles maintained non-zero locomotor activity thorough the winter. • Monthly means of body temperature and activity differed between two neighboring familiar groups. • Circadian and ultradian rhythms of body temperature and activity tended to decay in winter. [ABSTRACT FROM AUTHOR]

The Korchevo section with two layers of Quaternary Interglacial deposits is unique on the territory of Belarus. Deposits of this type occur in the middle part of the country at a depth of about 100 m on Narev moraine. These deposits in Korchevo were removed to the surface as a result of glaciotectonic processes and became available for paleontological studies. The location of fossil mammal fauna from Korchevo is the only one on the territory of Belarus, where the autochthonous complex of the ancient Middle Pleistocene mammals of Belarus studied on thousands remains of the of rodents teeth. The primitive root vole Mimomys intermedius (Newton) is the species of Alizarovian and Korchevian fauna. Seed flora, fauna of molluscs, insects and ostracods were the oldest in Middle Pleistocene. Paleontological studies were the basis for the allocation of stratigraphic units (Alizarovian Interglacial, Nevdian Glacial and Korchevian Interglacial) in the Middle Pleistocene of Belarus. Interglacial deposits of the key-site are very well correlated with Augustovian Interglacial formations in Poland. They correspond to parts of Cromer and Bavel complexes in the European stratigraphic scale of the Quaternary system. [ABSTRACT FROM AUTHOR]

The function of estrogen-related receptor (ERR) in testicular cells is at the beginning of exploration. Our previous findings showed that expression pattern of estrogen-related receptor (ERR) in mouse Leydig cell depends on physiological status of the cell. Exogenous hormones/hormonally active chemicals affect ERR expression. In Leydig cells in vitro, ERRα and ERRγ show opposing regulatory properties. The aim of this study was to examine the role of ERR in epigenetic processes in cells with altered level of secreted estrogens; mouse tumor Leydig cells and bank vole Leydig cells, respectively. In Leydig cells, ERRα and ERRγ were silenced via siRNA. mRNA and protein expression and protein localization of molecules required for miRNA biogenesis and function (Exportin 5, Dicer, Drosha and Argonaute 2; Ago2) were studied with the use of qRT-PCR, Western blotting, and immunohistochemistry. Global DNA methylation and histone deacetylation status together with estradiol secretion were determined with fluorometric, and immunoenzymatic assays. Regardless of ERR type knockdown in tumor Leydig cells, downregulation (P < 0.05; P < 0.01; P < 0.001) of Exportin5, Dicer, Drosha but not Ago2 was revealed while at protein level only Drosha was downregulated (P < 0.01) by both ERRα and ERRγ. Oppositely, Exportin5, Dicer and Ago2 showed ERR type-dependent regulation (downregulation; P < 0.01 by ERRα and upregulation; P < 0.01; P < 0.001 by ERRγ). In ERR-silenced vole Leydig cells, expression of Exportin5, endonucleases and Ago2 was not changed. Immunolocalization of Dicer and Ago2 was independent of the cell origin in contrast to localization of Exportin5 and Drosha which was dependent on the cell origin and ERR type knockdown. Absence of ERR effected on cell methylation status (ERRα increased it; P < 0.01 while ERRγ decreased it; P < 0.01, P < 0.001) but it not changed histone deacetylates activity. ERRα and ERRγ silencing decreased (P < 0.01, P < 0.001) estradiol secretion in both tumor and vole Leydig cells. In mouse and bank vole Leydig cell, Exportin5, Dicer, Drosha and Ago2 expression as well as methylation status are regulated by ERR in a manner related to receptor type, molecule type, cell origin and level of secreted estrogen. • Drosha, Exportin5, Dicer and Argonaute2 are expressed in bank vole and mouse tumor (MA-10) Leydig cells. • In MA-10 cells, proteins required for miRNA biogenesis and function are regulated by estrogen-related receptor (ERR). • In bank vole Leydig cells, ERRα and γ do not regulate protein expression of Drosha, Exportin5, Dicer and Argonaute2. • In Leydig cell, DNA methylation is dependent on cell origin, secreted estrogen level and type of ERR. • In bank vole and mouse tumor Leydig cells, histone deacetylation is controlled neither by ERR nor estrogen level. [ABSTRACT FROM AUTHOR]

Two cricetids and three arvicolines are added to the Fiene local fauna (Irvingtonian) of north-central Kansas. Cricetids include the harvest mouse, Reithrodontomys moorei and grasshopper mouse, Onychomys sp. Arvicolines include the muskrat, Ondatra annectens , red-backed vole, Myodes gapperi , and bog lemming, Mictomys kansasensis. The latter two; taxa are extralimital and indicate cooler and wetter summers than at present in the area. Likewise, the record of Myodes represents the earliest occurrence of the taxon on the central Plains. The rarity of Onychomys relative to the previously reported abundant microtids in the Fiene local fauna indicates that the transition from a granivorous diet in the Blancan to a primarily insectivorous diet it has today was completed during Irvingtonian II. [ABSTRACT FROM AUTHOR]

The maximum rate of aerobic exercise metabolism (VO 2 max) is a trait informative from both medical and evolutionary perspective, and both the physiological mechanisms limiting its level and its evolution are subject to vivid debate. Both comparative analyses and studies on the effects of training or acclimation to aerobically-demanding conditions suggest a role of oxygen transport-related properties of blood in limiting VO 2 max. Here we used a unique experimental evolution model – lines of bank voles selected for high rate of swim-induced aerobic metabolism (VO 2 swim; A lines), which evolved a 60% higher VO 2 swim than that observed in unselected control lines (C) – and asked how the hematological parameters evolved in response to the selection. Voles from the A lines had a decreased hemoglobin concentration in cardiac blood samples (adjusted means ± SE, A: 14.7 ± 1.1, C: 15.3 ± 1.1 g/dl; p =.008), hematocrit (A: 51.7 ± 4.5, C: 53.8 ± 4.2%; p =.042) and tended to have less erythrocytes per microliter of blood (A: 11.5 ± 1.4, C: 12.7 ± 1.3 mln/μl; p =.083). The effect of selection was more pronounced in males than in females. Thus, selection for high aerobic-exercise performance resulted in a paradoxical decrease in traits positively associated with oxygen-carrying capacity per unit of blood volume, and the effect was sex-dependent. However, as a decreased blood viscosity associated with the lowered hematocrit reduces the costs of blood circulation, it can be hypothesized that the change can actually boost the oxygen supply to peripheral tissues. • The artificial selection resulted in a 60% increase of aerobic exercise metabolism. • The correlated response in hematological parameters was sex-specific. • Hematocrit and hemoglobin concentration decreased in males from the selected lines. [ABSTRACT FROM AUTHOR]

Abstract Prairie voles are socially monogamous mammals that form pair bonds and display paternal care. This study was focused on the male prairie vole's neuronal responses to infant-related odors. Using the fos protein as a measure of neuronal activation, we examined the brain responses of males to infant-related odors. Prior to testing, the subjects had cohabited for two weeks with either a male sibling (Male-Cohabited) or an unrelated female (Female-Cohabited). Given that paternal behavior of male prairie voles is enhanced after two-weeks of cohabitation with a mate, we hypothesized that fos activation in brain regions involved in caring must be increased in response to infants or their odors but not in response to water or sub-adult odors. To test this hypothesis, we analyzed the pattern of fos expression in the ventral tegmental area (VTA) and the bed nucleus of the stria terminals (BNST) two hours after Male-Cohabited and Female-Cohabited males were exposed to either two live infants or to odors of infants, sub-adults or water. Results showed differences in fos expression within the VTA between Male-Cohabited and Female-Cohabited subjects that were exposed to infants and infant odors. The type of cohabitation had no effect on fos expression within the BNST, but the pattern of fos activation in this region differed by the type of odor to which the subjects were exposed. Together, the data indicate that female sensory cues during post-mating cohabitation may be processed within the VTA to direct the male prairie vole's responses towards infants. [ABSTRACT FROM AUTHOR]

Negative social experiences influence both depression and cardiovascular dysfunction. Many individuals who experience negative mood states or cardiovascular conditions have limited social support. Therefore, investigation of drug treatments that may protect against the consequences of social stress will aid in designing effective treatment strategies. The current study used an animal model to evaluate the protective effect of sertraline administration on behavioral and cardiovascular consequences of social stress. Specifically, male prairie voles (Microtus ochrogaster), which are socially monogamous rodents that share several behavioral and physiological characteristics with humans, were isolated from a socially-bonded female partner, and treated with sertraline (16 mg/kg/day, ip) or vehicle during isolation. Unexpectedly, sertraline did not protect against depression-relevant behaviors, and it was associated with increased short- and long-term heart rate responses. However, sertraline administration improved heart rate variability recovery following a behavioral stressor, including increased parasympathetic regulation, and altered long-term neuronal activity in brain regions that modulate autonomic control and stress reactivity. These results indicate that sertraline may partially protect against the consequences of social stressors, and suggest a mechanism through which sertraline may beneficially influence neurobiological control of cardiac function. • Social stressors contribute to emotional and autonomic dysfunction. • The prairie vole is useful model to study the effects of social stressors. • Sertraline improved heart rate variability recovery after stress in isolated voles. • Sertraline's benefits may involve changes in central autonomic network regions. [ABSTRACT FROM AUTHOR]

• The occurrence of E. cuniculi in Apodemus spp. and Myodes glareolus was reported for the first time. • The highest infection rate was recorded for A. flavicollis. • E. cuniculi genotype II was the most frequently recorded. • Uncommon in rodents, E. cuniculi genotypes I and III, were also identified. Encephalitozoon spp. is an obligate intracellular microsporidian parasite that infects a wide range of mammalian hosts, including humans. This study was conducted to determine the prevalence of Encephalitozoon spp. in wild living rodents from Poland, the Czech Republic and Slovakia. Faecal and spleen samples were collected from individuals of Apodemus agrarius , Apodemus flavicollis , Apodemus sylvaticus , and Myodes glareolus (n = 465) and used for DNA extraction. PCR, targeting the ITS region of the rRNA gene was performed. The overall prevalence of microsporidia was 15.1%. The occurrence of Encephalitozoon cuniculi in the abovementioned host species of rodents has been presented for the first time, with the highest infection rate recorded for A. flavicollis. Sequence analysis showed that the most frequent species was E. cuniculi genotype II (92.5%). E. cuniculi genotypes I (1.5%) and III (6.0%) were also identified. [ABSTRACT FROM AUTHOR]

Highlights • "Observers" greatly increased grooming toward their defeated partners. • Fos expressions were elevated in some brain structures. • OT and GABA neurons were activated in the PVN and ACC, respectively. • Consolation was blocked by an OT or a GABA A receptor antagonist within the ACC. Abstract Consolation, which entails comforting contact directed toward a distressed party, is a common empathetic response in humans and other species with advanced cognition. Here, using the social defeat paradigm, we provide empirical evidence that highly social and monogamous mandarin voles (Microtus mandarinus) increased grooming toward a socially defeated partner but not toward a partner who underwent only separation. This selective behavioral response existed in both males and females. Accompanied with these behavioral changes, c-Fos expression was elevated in many of the brain regions relevant for emotional processing, such as the anterior cingulate cortex (ACC), bed nucleus of the stria terminalis, paraventricular nucleus (PVN), basal/basolateral and central nucleus of the amygdala, and lateral habenular nucleus in both sexes; in the medial preoptic area, the increase in c-Fos expression was found only in females, whereas in the medial nucleus of the amygdala, this increase was found only in males. In particular, the GAD67/c-Fos and oxytocin (OT)/c-Fos colocalization rates were elevated in the ACC and PVN, indicating selective activation of GABA and OT neurons in these regions. The "stressed" pairs matched their anxiety-like behaviors in the open-field test, and their plasma corticosterone levels correlated well with each other, suggesting an empathy-based mechanism. This partner-directed grooming was blocked by pretreatment with an OT receptor antagonist or a GABA A receptor antagonist in the ACC but not by a V1a subtype vasopressin receptor antagonist. We conclude that consolation behavior can be elicited by the social defeat paradigm in mandarin voles, and this behavior may be involved in a coordinated network of emotion-related brain structures, which differs slightly between the sexes. We also found that the endogenous OT and the GABA systems within the ACC are essential for consolation behavior in mandarin voles. [ABSTRACT FROM AUTHOR]

Abstract Sensory gating, the ability to suppress sensory information of irrelevant stimuli, is affected in several neuropsychiatric diseases, notably schizophrenia and autism. It is currently unclear how these deficits interact with other hallmark symptoms of these disorders, such as social withdrawal and difficulty with interpersonal relationships. The highly affiliative prairie vole (Microtus ochrogaster) may be an ideal model organism to study the neurobiology underlying social behavior. In this study, we assessed unimodal acoustic sensory gating in male and female prairie voles using the prepulse inhibition (PPI) paradigm, whereby a lower amplitude sound (prepulse) decreases the startle response to a high amplitude sound (pulse) compared to the high amplitude sound alone. Prairie voles showed evidence of PPI at all prepulse levels compared to pulse alone, with both males and females showing similar levels of inhibition. However, unlike what has been reported in other rodent species, prairie voles did not show a within-session decrease in startle response to the pulse alone, nor did they show a decrease in startle response to the pulse over multiple days, highlighting their inability to habituate to startling stimuli (short- and long-term). When contrasted with a cohort of male wildtype C57Bl/6J mice that underwent a comparable PPI protocol, individual voles showed significantly higher trial-by-trial variability as well as longer latency to startle than mice. The benefits and caveats to using prairie voles in future sensory gating experiments are discussed. [ABSTRACT FROM AUTHOR]

Abstract Spatial processing is a critical component for survival. This domain of information processing has been extensively studied in rats and mice. Limited work has examined the capacity of other rodent species, like the prairie vole (Microtus ochrogaster), to process spatial information. The Morris water task (MWT) is a classic spatial task that has been used to examine spatial cognition in rodents. This task involves an animal developing configural relationships between extra-maze cues and the location of a hidden platform to successfully escape from a pool of water. The current study compared performance in the MWT between rats and prairie voles. Rats were observed to outperform prairie voles in key aspects of the task including latency to find the platform, directness of swim paths to the platform, and degrees of heading error. These results may be attributed to potential interspecies differences in spatial cognition, stress reactivity, physiology, or motivation. This study provides the foundation for future work investigating the spatial cognition of prairie voles and the factors that contribute to water task performance in rodents. [ABSTRACT FROM AUTHOR]

Abstract This study tested the hypotheses that maternal and paternal effects differentially influence expression of their offspring's adult behavior and underlying neural mechanisms. We predicted that maternal influences would be greater than paternal influences on male offspring. We tested these hypotheses by cross-breeding two phenotypically-, behaviorally- and neuroanatomically-distinct populations of prairie voles (Microtus ochrogaster) from Illinois, which are highly prosocial, and Kansas, which are significantly less prosocial. Females from each population were crossed with males from the other population. F 1 crosses were tested as adults to determine the effect of parentage on the expression of prosocial behavior and aggression, using a same-sex dyadic encounter and a heterosexual partner preference test, and for the expression of oxytocin (OT) and arginine vasopressin (AVP) in the paraventricular nucleus of the hypothalamus (PVN). As predicted, all significant differences in males, behavioral, OT and AVP immunoreactivity, were associated exclusively with maternal influences. There was a significant effect of treatment in the OT immunoreactivity of females. The effect of treatment in females' OT was associated with an interaction of population and sex, while same-sex social interactions differences were associated with population. Finally, in females, paternity influenced heterosexual bonds, with females with Illinois sires forming a partner preference. The results indicate that maternal influences dominate in male offspring, suggesting a parent-of-origin effect, while paternal effects are limited to selected prosocial behavioral expression in daughters. [ABSTRACT FROM AUTHOR]

Brandt's vole (Lasiopodomys brandtii) is a species with hypoxia tolerance, and glucose serves as the primary energy substrate under hypoxia. However, the glucose supply in Brandt's voles under hypoxia has not been studied. This study aimed to investigate characteristics in physiological indices and liver gene expression associated with glucose supply in Brandt's voles under hypoxia. Serum glucose of Brandt's voles remained stable under 10% O 2 , increased under 7.5% O 2 , and decreased under 5% O 2. Serum lactate increased under 10% O 2 , decreased under 7.5% O 2 , increased at 6 h and decreased at 12 h under 5% O 2. Liver glycogen increased under 10% O 2 , remained constant under 7.5% O 2 , and reduced under 5% O 2. Pepck and G6pase expression associated with gluconeogenesis decreased under 10% O 2 , while Pepck expression decreased and G6pase expression increased under 7.5% and 5% O 2. Regarding genes related to glycogen metabolism, Gys expression decreased at all oxygen concentrations, Phk expression increased under 5% O 2 , and Gp expression increased under 7.5% and 5% O 2. The alterations in glucose, lactate, liver glycogen, and gene expression related to glycogenolysis in Kunming mice (Mus musculus , control species) are similar to discovery of Brandt's voles under 7.5% O 2 , but gene expression involved in gluconeogenesis and glycogen synthesis increased. The findings suggest that Brandt's voles are more tolerant to hypoxia than Kunming mice, and their physiological indices and liver gene expression related to glucose supply exhibit species- and oxygen concentration-specific responses to hypoxia. This research offers novel insights for studying hypoxia tolerance of Brandt's voles. [Display omitted] • Serum glucose in Brandt's voles increased at 7.5% O 2 , but decreased at 5% O 2. • Liver glycogen and serum lactate exhibited variations under different hypoxia. • Changes in liver gene expression related to gluconeogenic metabolism were observed. • Alterations in liver gene expression related to glycogen metabolism were found. • These changes are species- and oxygen concentration-specific. [ABSTRACT FROM AUTHOR]

Behaviors, emotions, and cardiovascular functions are influenced by stress. But these detrimental effects are not exclusive to an individual that directly experiences stress. Stress is also experienced vicariously through observation of another individual undergoing stress. The current study used the strong social bonds in socially monogamous prairie voles to determine effects of repeated vicarious stress on cardiac and behavioral outcomes. Male prairie voles were exposed to either a 5-minute open field chamber alone [separate (control)] or while concurrently witnessing their sibling undergo a tail-suspension stressor [concurrent (experimental)], repeated across 4 sessions. Cardiac responses in animals in the open field were evaluated for heart rate and heart rate variability prior to, during, and after each test session, and behaviors were evaluated for motion, exploration, stress reactivity, and anxiety-relevant behaviors during each test session. The concurrent condition (versus separate) displayed increased heart rate and reduced heart rate variability during repeated test sessions, and impaired recovery of these parameters following the test sessions. The pattern of disturbances suggests that both increased sympathetic and reduced parasympathetic influence contributed to the cardiac responses. Animals in the concurrent condition (versus separate) displayed disrupted rearing, grooming, and motion; reduced duration of center section exploration; and increased freezing responses across repeated test sessions. Collectively, cardiac and behavioral stress reactivity are increased as a function of vicarious stress in prairie voles, which are evident across repeated experiences of stress. These results inform our understanding of the experience of vicarious stress in social species, including humans. [ABSTRACT FROM AUTHOR]

• TA significantly increased serum total cholesterol concentration and decreased the nutrient digestibility of Brandt's voles. • The small intestine of male Brandt's vole between the control and tannic acid groups were analyzed by RNA sequencing. • There were 174 DEGs in the duodenum, 96 DEGs in the jejunum, and 88 DEGs in the ileum. • Many genes associated with fat digestion and absorption were altered after tannic acid treatment. Tannic acid (TA), a significant plant secondary metabolite, is contained in the daily food of Brandt's voles. Its adverse effect on gut function has been shown in earlier research, but the underlying molecular mechanisms remain uncertain. In this study, male Brandt's vole (13 weeks old) were divided into two groups and given 0 (control) or 1,200 (TA-treated) mg•kg−1 TA for 18 days. Then RNA sequencing was used to conduct a thorough transcriptome analysis on the duodenum, jejunum, and ileum of Brandt's voles. Results showed that TA significantly increased serum total cholesterol concentration (P < 0.05) and decreased the nutrient digestibility (P < 0.05) of Brandt's voles. Furthermore, there were 174 differentially expressed genes (DEGs) in the duodenum, 96 DEGs in the jejunum, and 88 DEGs in the ileum between the control and TA-treated groups. Enrichment analysis revealed that many genes associated with bile secretion, fat digestion and absorption, innate immune response, and tight junction such as ABCG2 , ABCG8 , PEAK1 , and IFR2 , etc. were altered after TA treatment, which were verified by quantitative real-time PCR. These findings suggested that TA can change the expression of intestinal genes, thereby, altering nutrition metabolism and immunological function, eventually hindering the growth of Brandt's voles. The results of this study provide a theoretical basis for explaining how TA affects the gut function of Brandt's voles at the molecular level. [ABSTRACT FROM AUTHOR]

Hemorrhagic fever with renal syndrome (HRFS) is endemic disease in the Republic of Tatarstan (RT). Infection is caused by Puumala orthohantavirus (PUUV) circulating in bank vole (Myodes glareolus) small rodents. However, knowledge on the connection between viruses identified in patients and bank voles is still limited in the RT. Establishing the link between virus strains in patients and bank voles could help to determine the site of infection. Total RNA was extracted from HFRS serum samples. The amplified PCR-products were obtained by RT-PCR using S and M segments specific primers and sequenced. PUUV RNA was detected in 88 out of 201 HFRS samples. The nucleotide sequences from 42 and 24 PUUV strains for S and M segments were obtained. Phylogenetic analysis had demonstrated that HFRS strains formed 7 (S segment) and 6 (M segment) groups. Most of these strain sequences matched sequences obtained from bank voles captured in the same area where patients presumably were infected. One PUUV strain detected in a patient infected in the Smak-Korsa village, contains the S segment from group G and the M segment from group D, suggesting that this strain is the result of reassortment. Also, four reassortant genomes were identified in HFRS cases presumably infected near Vysokaya Gora village. These results suggest that the PUUV strain in HFRS patient would be similar to that circulating in bank voles which habitat in the same region. Therefore, by identifying PUUV genome in HFRS patients, virus distribution within the area and dissemination to other regions could be monitored. Also, reassortant PUUV strains were found exclusively in HFRS, while they were absent in bank voles. This study was supported by RFBR perspective grant 19-34-60012 and RSF-DST 22-44-02007 grant. Also, the Kazan Federal University Strategic Academic Leadership Program (PRIORITY-2030) funded this research. [ABSTRACT FROM AUTHOR]

Highlights • Mitigation occurred for one species in response to perceived rarity. • Two vole species had their greatest abundance in forests >80 years old. • Patterns of abundance were qualitatively similar between two vole species. • A comparative species approach was instructive in assessing rarity. Abstract Species rarity is often an important driver of conservation priorities in lieu of greater knowledge of extinction risk. Land management agencies often prioritize management based in part on the commonness of a species, yet identifying what constitutes where a species lies on the commonness-rarity continuum is difficult. Given limited resources, incorrect classification may have detrimental effects on species conservation. In a large area of the Northwest Forest Plan, which guides management of 9.1 million ha of federal forests in the Pacific Northwest, USA, forest management is closely tied to mitigation for the red tree vole (Arborimus longicaudus), a species considered uncommon due in part to its association with older forests. I explore the ability to provide insight into where a species lies along the commonness-rarity continuum by a multi-species comparison. I compared the relative distribution, abundance, and extrinsic conservation threats of red tree voles to western red-backed voles (Myodes californicus), a similar species considered common. Both species occur in younger forests with legacy components of older forests, but reach their greatest densities within older forests. Densities of the two vole species were qualitatively similar. If assignment of a species along a commonness-rarity continuum is a goal of species surveys, their value may be enhanced by including in the survey a set of similar species whose level of rarity is better understood. Although management of the red-tree vole was intended to be guided by adaptive management, challenging policy and legal issues have made that difficult; rarity as a criterion for prioritizing management is partly responsible. [ABSTRACT FROM AUTHOR]

Abstract For several mammalian species, both population levels and distribution ranges are predicted to change due to changing habitat conditions caused by climate change. A general decrease in the amplitude of small rodent population cycles in northern Europe since the late 1980s has commonly been attributed to a lack of permanent snow cover during winter, or to unfavourable snow conditions. An alternative explanation is that increasing summer temperatures and an extended growing season are unfavourable for herbivorous rodents, by reducing the forage quality. If so, the negative effect should be stronger for the strictly herbivorous Microtus voles than for the herbivorous-granivorous Myodes voles. In a previous study small rodents were snap trapped in 22 regions in Norway during 1971–1979. We found that the trapping index of Microtus voles, but not Myodes voles, in this study was negatively related to summer temperatures. Both in this study and in a snap trapping study from 1994 to 2015, conducted in 13 study areas in Norway, the proportion of Microtus voles among voles captured was negatively related to summer temperatures. Summer temperature was a better predictor than snow depth, but both variables contributed significantly in multiple regression models. We conclude that summer temperature is likely to be a more important factor than snow cover for the population dynamics of herbivorous voles in northern Europe. Highlights • Low vole numbers during the 1990s and early 2000s has been linked to climate change. • Possible drivers are unfavourable snow conditions and high summer temperatures. • Decreased forage quality in warm summers should mainly affect herbivorous species. • Summer temperatures was the best predictor for herbivorous vole number in Norway. [ABSTRACT FROM AUTHOR]

Coccidia of the genus Isospora , their origin, taxonomy, and host specificity have been discussed for many years. The crucial point in question being the division of the genus, based on distinct evolutionary history and the presence/absence of the Stieda body, into the genera Isospora (Eimeriidae) parasitizing mainly birds and reptiles, and Cystoisospora (Sarcocystidae) parasitizing mammals. The description of the majority of Isospora species from rodents is based solely on the oocysts found in their faeces. Some of them have been described with the presence of the Stieda body, some without it, and, simultaneously, for all the described species the molecular data are entirely lacking. This study reveals the origin of isosporan oocysts found in faeces of bank voles based on morphological analyses, phylogenetic analyses, and experimental infections. Morphological analyses showed the presence of the Stieda body complex on sporocysts. Phylogenetic analyses demonstrated close phylogenetic relationships between Isospora from bank voles and avian isosporans. Experimental inoculations of bank voles with sporulated oocysts of Isospora did not result in the production of unsporulated oocysts. Hence, these organisms should be considered pseudoparasites of the bank voles/rodents (probably originating from avian Isospora species). [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Intestinal epithelium develops during gestation and continues to mature post-natally into a selective barrier that will protect the individual while still allowing passage of nutrients. Until fully mature, the risk of translocation of microorganisms, toxins or antigens into the sub-epithelial tissue is high and could result in pathologies with life-altering consequences, or even premature death. Because of their monogamous mating system, prairie voles are an emerging model for studying the role of the intestinal microbiota in modulating social behavior via the microbiota-gut-brain-behavior axis. However, knowledge about the voles' intestinal barrier maturation is lacking. Understanding the maturation of the intestine epithelial barrier can complement the extensive behavioral literature for future studies involving the vole gut-brain axis. In this study, we characterized intestinal barrier function by demonstrating that two-week-old prairie voles have high paracellular absorption of FITC-dextran molecules prior to markedly decreased permeability at three weeks of age. In light of the fundamental role of tight junctions in maintaining epithelial integrity regulating intestinal permeability, we examined tight junction gene expression profiles. Transmission electron microscopy was used to visualize tight junction structure. Our results provide a timeline for intestinal barrier maturation and point to tight junction proteins involved in this process in prairie voles. [ABSTRACT FROM AUTHOR]

Some species of Microtus voles exhibit multi-annual population fluctuations with peak numbers every 3–5 years, and these periods may be interspersed with annual fluctuations in abundance. Populations of long-tailed voles ( M. longicaudus Merriam) increase during the first 3–4 years after clearcutting of coniferous forests, and it is during this population outbreak that voles may feed on newly planted tree seedlings. It is unclear if M. longicaudus has multi-annual population fluctuations similar to other Microtus species, and we do not know the location of refuge habitats during low years of abundance. We describe changes in abundance of M. longicaudus during the first 5–10 years after clearcut harvesting near Golden, British Columbia, Canada, and evaluated four hypotheses (H) that long-tailed voles will (H 1 ) have peak populations at 3–4 years post-harvest, decline to low numbers, with outbreak populations appearing again on newly clearcut sites; (H 2 ) occur at very low (<1 vole/ha) numbers in uncut forest; (H 3 ) persist at low numbers (<5 voles/ha) in riparian refuge sites; and (H 4 ) be at lower abundance when M. pennsylvanicus (Ord) is present at equal or higher numbers. Long-tailed vole populations increased in abundance on newly clearcut sites and reached independent peak numbers (62, 96, and 134/ha) at 3–4 years post-harvest in three different areas and time periods, thus supporting H 1 . Long-tailed voles were consistently at very low numbers in uncut forest, and hence this habitat did not provide a refuge or source area for voles, thereby supporting H 2 . We had some evidence to support H 3 that long-tailed voles seemed to persist at low numbers (<5/ha) in riparian refuge sites. Where both species of voles were present, results tended to not support H 4 . We conclude that M. longicaudus did not have a multi-annual population fluctuation in abundance, at least for the 9- to 11-year periods post-harvest that we investigated. Thus, tree mortality from an outbreak population of M. longicaudus , occurring at 3–4 years post-harvest, could be avoided by planning regeneration planting after this single peak population has subsided. Some long-tailed voles may persist past the peak population in, or near, riparian sites. These voles did not occupy old-growth forest, and hence they presumably migrate to new clearcuts via road networks facilitated by linear grass-dominated habitats. [ABSTRACT FROM AUTHOR]

The incorporation of the spatial heterogeneity of real landscapes into population dynamics remains extremely difficult. We propose combining equation-based modelling (EBM) and agent-based modelling (ABM) to overcome the difficulties classically encountered. ABM facilitates the description of entities that act according to specific rules evolving on various scales. However, a large number of entities may lead to computational difficulties (e.g., for populations of small mammals, such as voles, that can exceed millions of individuals). Here, EBM handles age-structured population growth, and ABM represents the spreading of voles on large scales. Simulations applied to the spreading of a montane water vole population demonstrated that our model is quite efficient in representing the pattern observed and might help to highlight some key parameters during population expansion. This method paves the way for further developments, including the introduction of density-dependent parameters (predation, diseases, etc.) capable of triggering population declines in an explicitly spatial context. [ABSTRACT FROM AUTHOR]

Microfaunal remains are commonly used as palaeoenvironmental proxies and have been proposed as a means to identify relative ages of Late Quaternary deposits through biostratigraphy (i.e., utilising ‘Mammal Assemblage Zones’). However, assemblages of faunal remains can include a diverse range of taxa which are often difficult to distinguish using morphological aspects of the surviving bones, particularly when diagnostic features are eroded or missing due to fragmentation. Here we investigate the application of a recently developed method of species identification by collagen fingerprinting to arvicoline rodents (voles and lemmings), the dominant mammalian taxonomic group present at the Late Pleistocene site of Pin Hole Cave, Creswell Crags U.K., which is currently the designated British type locality for the Pin Hole Mammal Assemblage Zone (Oxygen Isotope Stage 3) fauna. We also further explore the potential for studying collagen decay rate via deamidations, and their applicability across the species boundary, in terms of its use for relative ageing of remains. Our results demonstrate the ease with which some taxa can be objectively distinguished to genus (e.g. Microtus from Myodes and Lemmus from Dicrostonyx ) and in some cases species (e.g., M. gregalis from M. oeconomus ), but that the potential for relative ageing is complicated by a range of taphonomic factors. The results highlight the potential for this new technique in much larger-scale palaeoenvironmental studies investigating temporal changes in vertebrate biodiversity. [ABSTRACT FROM AUTHOR]

Voles are among the most common and abundant rodents in Central Europe, represented by several species of Microtus and other genera. This group is also common in Pleistocene fossil assemblages. However, the taxonomy of fossil finds, largely based on lower first molars, is fraught with problems and opinions of various authors often diverge, hampering phylogenetic inferences and reconstruction of lineages which led to the extant species. To help solve taxonomic incongruence, we carried out morphometric analyses on the abundant late Early Pleistocene finds from the exceptionally rich site of Somssich Hill 2 (Villány Mts., southern Hungary), complemented with less numerous but also well-dated and nearly coeval material from nearby sites Villány 6 and 8, as well as Kövesvárad from northern Hungary. Landmark analysis was performed in the present paper, and in addition, cluster and discriminant analyses were applied on the conventional linear data derived from the landmark coordinates. First lower molars of well-established recent taxa from zoological museum collections were also included in the analyses, both to assess their degree in intraspecific morphological variability to inform delineation of the extinct taxa, and to compare morphologies of fossil and recent taxa to establish phylogenetic relationships. Morphometric analyses revealed that the material from Somssich Hill 2 represents a single species, Microtus nivaloides , whereas specimens from the somewhat younger site Villány 8 belong to M. nivalinus . Paleoecology of the accompanying taxa in the fossil assemblages suggests differences in their habitat: M. nivalinus preferred more open vegetation, whereas M. nivaloides was restricted to forested areas. Geometric morphometric analyses together with modern taxa defined a morphospace where the consensus shape of M. nivaloides is centrally located, supporting the hypothesis that it represents the ancestor of modern Microtus ( Microtus ) species and forms part of a lineage which led to the M . arvalis-agrestis group. On the other hand, morphological similarities suggest a split lineage and phylogenetic relations of late Early Pleistocene M. nivalinus and the recent M. oeconomus. The emergence of ‘true’ Microtus species stems from the radiation initiated around 1.0–0.9 Ma, an important phase in vole evolution revealed by the rich finds from Somssich Hill 2 and other sites. [ABSTRACT FROM AUTHOR]

Voles of the genus Microtus are considered the major mammalian pest species affecting tree fruit crops in North America and Europe. During winter, voles feed on bark, vascular tissues, and sometimes roots of trees. Rodenticides continue to be the major method used to reduce vole populations in orchards, but an alternative approach could be a living mulch along tree rows that would provide weed management, have a low growth habit, and be repellent to voles. We examined four living mulches installed in young apple orchards: hairy vetch ( Vicia villosa Roth), birdsfoot trefoil ( Lotus corniculatus L.), sweet woodruff ( Galium odoratum (L.) Scop.), and creeping thyme ( Thymus serpyllum L.). Forage grasses were used as a “control” in two experiments. Efficacy of these mulches was evaluated by their growth and effects on (1) abundance of total orchard herbaceous plants, (2) abundance of montane voles ( Microtus montanus Peale), and (3) feeding damage to apple trees in field trials at Summerland, British Columbia, Canada in 2007–2010. A sixth treatment, glyphosate herbicide, was added in Experiment 2. Hairy vetch and birdsfoot trefoil did not suppress herbaceous vegetation along tree rows, but birdsfoot trefoil had fewer voles than either hairy vetch or forage grasses. Sweet woodruff and creeping thyme both reduced abundance of orchard herbs compared with the control forage grasses and this effect was maintained for two of three growing seasons. Forage grasses and sweet woodruff had increasing proportions of mulch dominating the growing sites, whereas creeping thyme did not. Both sweet woodruff and creeping thyme seemed to repel voles with reduced damage to trees in two winters, but not summer 2010, compared with the forage grasses sites. Vole numbers were, on average, 1.4 to 4.9 times higher in the forage grasses than the other two sites. However, the relatively high degree of feeding damage (>45% mortality) to young apple trees (except for 16% mortality for creeping thyme in one winter) in all three seasons was a major limitation. These tree mortality levels are unacceptable economically and suggest strongly that living mulches may not be a practical solution for weed management in organic or conventional orchards. Orchard-scale experiments that emulate real-world farming practices might yield living mulch habitats that are not as desirable for voles as those examined in our study. Herbicide sites had the lowest abundance of herbaceous vegetation, voles, and provided complete protection of apple trees compared to than any of the other treatment sites. [ABSTRACT FROM AUTHOR]

Although pair bonding is the preferred mating tactic among socially monogamous prairie voles, naturalistic observations have demonstrated many males remain non-bonded. Moreover, although males readily re-bond after the loss of a partner, females do not (i.e., the "widow effect'). Few studies have attempted to address why so many males remain non-bonded or if a reluctance of re-bonding in females contributes to this outcome. We investigate how female bonding history impacts male pair bond formation. Specifically, we test two alternative hypotheses for how sexually naïve males will behave when paired with widow females. The fecundity hypothesis predicts males will avoid bonding with widow females and be more receptive to novel bond-naïve females. The preference to bond hypothesis predicts males will choose to bond and express a partner preference, irrespective of if a pair-mate is a widow or sexually naïve. Our results demonstrated that males expressed a partner preference for females regardless of their social history. These data support the preference to bond hypothesis and suggest natural variation in bonding may not be strongly due to males forgoing bonding opportunities. • Previous work showed widow females do not form new bonds. • We show male prairie voles do not avoid bonding with widow females. • Female social history does not influence male decisions to pair bond. • These data provide additional support for the male preference to bond hypothesis. [ABSTRACT FROM AUTHOR]

Gestational flame retardant (FR) exposure has been linked to heightened risk of neurodevelopmental disorders, but the mechanisms remain largely unknown. Historically, toxicologists have relied on traditional, inbred rodent models, yet those do not always best model human vulnerability or biological systems, especially social systems. Here we used prairie voles (Microtus ochrogaster), a monogamous and bi-parental rodent, leveraged for decades to decipher the underpinnings of social behaviors, to examine the impact of fetal FR exposure on gene targets in the mid-gestational placenta and fetal brain. We previously established gestational exposure to the commercial mixture Firemaster 550 (FM 550) impairs sociality, particularly in males. FM 550 exposure disrupted placental monoamine production, particularly serotonin, and genes required for axon guidance and cellular respiration in the fetal brains. Effects were dose and sex specific. These data provide insights on the mechanisms by which FRs impair neurodevelopment and later in life social behaviors. • Flame retardants are indoor and environmental contaminants and developmental neurotoxicants. • We used a prosocial animal model, the prairie vole, to assess impact of gestational exposure on brain and fetal placenta. • Placental monoamine production was disrupted, particularly serotonin. • Placental cellular respiration and stress pathways were disrupted. • In fetal brain, neuronal progenitor genes were downregulated and axon guidance genes upregulated. [ABSTRACT FROM AUTHOR]

The bank vole is a common Cricetidae rodent that is a reservoir of several zoonotic pathogens and an emerging model in eco-immunology. Here, we add to a developing immunological toolkit for this species by testing the cross-reactivity of commercially available monoclonal antibodies (mAbs) to the bank vole lymphocyte differentiation molecules and a transcription factor. We show that a combination of mAbs against CD4, CD3, and Foxp3 allows flow cytometric distinction of the main subsets of T cells: putative helper CD4+, cytotoxic CD8+ (as CD3+CD4-) and regulatory CD4+Foxp3+. We also provide a comparative analysis of amino acid sequences of CD4, CD8αβ, CD3εγδ and Foxp3 molecules for a number of commonly studied Cricetidae rodents and discuss mAb cross-reactivity patterns reported so far in this rodent family. We found that in case of mAbs targeting the extracellular portions of commonly used T cell markers, sequence similarity is a poor prognostic of cross-reactivity. Use of more conserved, intracellular molecules or molecule fragments is a more reliable approach in non-model species, but the necessity of cell fixation limit its application in, e.g. functional studies. • New resources for a budding immunological toolkit available for the bank vole – common rodent reservoir of zoonotic pathogens. • Cross-reactive mAbs with CD3, CD4 and Foxp3 molecules of the bank voles were identified. • Combined use of these mAbs can differentiate major T cell subsets in bank voles. • mAb cross-reactivity between Muridae and Cricetide poorly corelates with sequence similarity. [ABSTRACT FROM AUTHOR]

Patients with epilepsy are significantly burdened by the disease due to long-term health risks, the severe side effect profiles of anti-epileptic drugs, and the strong possibility of pharmacoresistant refractory seizures. New animal models of epilepsy with unique characteristics promise to further research to address these ongoing problems. Here, we characterize a newly developed line of prairie voles (Microtus ochrogaster , UTol:HIC or "Toledo" line) that presents with a hereditary, adult-onset, handling-induced convulsion phenotype. Toledo voles were bred for four generations and tested to determine whether the observed phenotype was consistent with epileptic seizures. Toledo voles maintained a stable 22 % incidence of convulsions across generations, with an average age of onset of 12–16 weeks. Convulsions in Toledo voles were reliably evoked by rodent seizure screens and were phenotypically consistent with murine seizures. At the colony level, Toledo voles had a 7-fold increase in risk for sudden unexpected death from unknown causes, which parallels sudden unexpected death in epilepsy (SUDEP) in human patients. Finally, convulsions in Toledo voles were reduced or prevented by treatment with the anti-epileptic drug levetiracetam. Taken in combination, these results suggest that convulsions in Toledo voles may be epileptic seizures. The Toledo prairie vole strain may serve as a new rodent model of epilepsy in an undomesticated, outbred species. • The Toledo strain of prairie voles shows a hereditary convulsion phenotype. • Convulsions resemble murine seizures and are evoked using murine seizure screens. • Convulsions are prevented using an anti-epileptic drug. • Convulsions in Toledo voles may be epileptic seizures. [ABSTRACT FROM AUTHOR]