Common Vole Microtus Arvalis Research Articles

Mechanisms of temperature modulation in mammalian seasonal timing.

Global warming is predicted to have major effects on the annual time windows during which species may successfully reproduce. At the organismal level, climatic shifts engage with the control mechanism for reproductive seasonality. In mammals, laboratory studies on neuroendocrine mechanism emphasize photoperiod as a predictive cue, but this is based on a restricted group of species. In contrast, field-oriented comparative analyses demonstrate that proximate bioenergetic effects on the reproductive axis are a major determinant of seasonal reproductive timing. The interaction between proximate energetic and predictive photoperiodic cues is neglected. Here, we focused on photoperiodic modulation of postnatal reproductive development in common voles (Microtus arvalis), a herbivorous species in which a plastic timing of breeding is well documented. We demonstrate that temperature-dependent modulation of photoperiodic responses manifest in the thyrotrophin-sensitive tanycytes of the mediobasal hypothalamus. Here, the photoperiod-dependent expression of type 2 deiodinase expression, associated with the summer phenotype was enhanced by 21°C, whereas the photoperiod-dependent expression of type 3 deiodinase expression, associated with the winter phenotype, was enhanced by 10°C in spring voles. Increased levels of testosterone were found at 21°C, whereas somatic and gonadal growth were oppositely affected by temperature. The magnitude of these temperature effects was similar in voles photoperiodical programmed for accelerated maturation (ie, born early in the breeding season) and in voles photoperiodical programmed for delayed maturation (ie, born late in the breeding season). The melatonin-sensitive pars tuberalis was relatively insensitive to temperature. These data define a mechanistic hierarchy for the integration of predictive temporal cues and proximate thermo-energetic effects in mammalian reproduction.

Negative Energy Balance Enhances Ultradian Rhythmicity in Spring-Programmed Voles.

Voles are small herbivorous rodents that can display both circadian activity rhythms (~24-h periodicity) and ultradian activity rhythms (~1- to 6-h periodicity). Ultradian rhythms are observed on an individual level, but also in synchronized populations. Ultradian rhythm period has been suggested to be influenced by energy balance, but the underlying mechanisms of ultradian rhythmicity are poorly understood. We manipulated energy balance by implementing the “work-for-food” paradigm, in which small rodents are exposed to increasing levels of food scarcity at different ambient temperatures in the laboratory. Photoperiodical spring-programmed voles on high workload changed their nocturnal circadian activity and body temperature rhythm to ultradian patterns, indicating that a negative energy balance induces ultradian rhythmicity. This interpretation was confirmed by the observation that ultradian patterns arose earlier at low temperatures. Interestingly, a positive relationship between ultradian period length and workload was observed in tundra voles. Spectral analysis revealed that the power of ultradian rhythmicity increased at high workload, whereas the circadian component of running wheel activity decreased. This study shows that the balance between circadian and ultradian rhythmicity is determined by energy balance, confirming flexible circadian and ultradian rhythms in females and males of 2 different vole species: the common vole (Microtus arvalis) and the tundra vole (Microtus oeconomus).

Influence of crop type on common vole abundance in Central European agroecosystems

In the Czech Republic, the abundance (burrow index (BI) of the common vole (Microtus arvalis), an herbivorous pest rodent in Central Europe, were collected in vole-suitable agricultural crops in spring and autumn. We used a 20-year data set that we predicted would cover enough spatial and temporal variations in the natural population fluctuations to allow us to test the effect of main crops. We found that permanent and perennial (i.e. alfalfa and clover) crops hosted the most abundant common vole populations among all studied crops. Among winter crops the population reached the greatest abundance in winter rape. In the growing season, (a) permanent and perennial crops, and to a lesser extent winter rape, maintained a high vole population during autumn and winter; (b) their population in winter cereals (winter barley and winter wheat) was consistently smaller compared to previous crops; (c) in sugar beet, in comparison with other crops, the population reached the highest level in two months of autumn (September and October) and (d) their population in spring barley reached a number comparable to winter cereals in only three months (March, April and May) of spring. We also revealed that the mild winter season positively influenced the common vole’s abundance. Fluctuations in the common vole’s BI in various crops over the 20-year time period were correlated and resulted in significant synchronisation. This led to the conclusion that permanent crops can serve as a good indicator for the prediction of the future development of species density and prevention.

Diet composition and prey choice by the Great Grey Shrike Lanius excubitor during the non-breeding period: comparing two methods of diet analysis

ABSTRACT Capsule The diet of the Great Grey Shrike Lanius excubitor during the non-breeding period was assessed using analysis of pellets and larders. The two methods gave different results but together showed a preference for voles, crickets and dung beetles. Aims To describe the diet composition of the Great Grey Shrike based on analyses of the contents of pellets and larders; to compare the two methods, and to compare prey taken in relation to its local availability. Methods The research was carried out during the non-breeding period of the Great Grey Shrike in an agricultural landscape of east-central Poland in 2014–2018. The diet was assessed through the analysis of the contents of larders and regurgitated pellets. The abundance of potential prey was assessed with pitfall traps for invertebrates and live traps for small mammals. Results In larders, the ratio of vertebrates to invertebrates was 34.3 : 65.7 (n = 528 prey items), with Orthoptera, Coleoptera and Rodentia predominant. In pellets, the ratio was 64.6 : 35.4 (n = 237 prey items in 155 pellets), with Rodentia and Coleoptera being most numerous. The proportions of the most frequently found prey taxa differed significantly between the two methods of diet analysis. In relation to potential prey availability, Great Grey Shrikes showed a preference for Common Voles Microtus arvalis but seemed to avoid mice Apodemus spp. and Diptera. The greatest discrepancies between the methods were for Coleoptera, Lepidoptera and Orthoptera. Conclusion The results of the pellet and larder analyses differed, mainly because of the large number of Orthoptera found in the larders; shrikes can use them to mark their territories and so they may remain uneaten. Both analytical methods should be used simultaneously to determine the diet composition.

Inferring phylogenetic relationships in the common vole (Microtus arvalis) based on mitochondrial and nuclear sequence diversities

The common vole Microtus arvalis (Pallas, 1778) is the most widespread Microtus species. It has two forms - the European arvalis form (2n: 46, NF: 84) and the Asian obscurus form (2n: 46, NF: 72). The present study aimed to clarify the taxonomic status of M. arvalis populations distributed in Eastern Turkey, Europe and Asia by analysing two mitochondrial (CYTB and COX1) and one nuclear (IRBP) markers. Phylogenetic dendrograms (median-joining networks and Bayesian trees) constructed using the mitochondrial markers clearly separated the Anatolian population from the European and Asian populations. Contrarily, any explicit differentiation was not shown in IRBP analyses. Mean and net genetic distance values (d) were found to be notably low for three markers. Species delimitation test (Automatic Barcode Gap Discovery Method) supported these results. Our results indicate that the arvalis and obscurus forms are not sufficiently differentiated to be considered different species, while the Anatolian population has only recently split from the Asian population. Together, these findings demonstrate that the speciation process is ongoing.

Trace metals accumulation in the eco-system water – soil – vegetation (Agropyron cristatum) – common voles (Microtus arvalis) – parasites (Hymenolepis diminuta) in Radnevo region, Bulgaria

BackgroundCoal and coal processing industries provoke trace metal pollution, which has a negative effect on the water – soil – vegetation – small mammals eco-system, constituting part of the food chain and exerting a serious impact on human health. ObjectivesAssessment of the environmental impact of Maritza iztok coal complex, situated east of Radnevo town, Bulgaria, by tracking the dynamics and accumulation of trace metals in the eco-system water – soil – vegetation – common voles – parasites. MethodsSamples from surface waters, their nearby uncultivated soils, meadow uncultivated vegetation (Agropyron cristatum) and field common voles (Microtus arvalis) were collected. In situ measurements and laboratory extraction procedures and analyses were performed. Accumulation and mobility indices were calculated. The distribution of dissolved Mn, Ni, Cu, Zn and Pb chemical species in water-soil extracts was calculated using a thermodynamic approach. Two thermodynamic models were applied – the classical ion-association model for calculating the inorganic trace metal species and the Stockholm Humic Model (SHM) accounting for the complexation reactions of trace metals with organic matter. Visual Minteq computer program, Version 3.1 was used. The relationship chemical species - bioaccumulation was discussed. ResultsPb and Mn, together with SO42− and PO43- were found to be the main pollutants of waters in the region. The soils studied exhibited low concentrations of trace metals, not exceeding the specified MACs. The content of Mn was the highest, followed by Zn, Pb, Cu and Ni. The highest phytoaccumulation coefficients in the studied uncultivated grass vegetation were calculated for Cu and Zn, being 1–2 orders of magnitude higher than those of Mn and Ni. The accumulation of trace metals was explained on the basis of ions mobility and chemical species distribution. In the case of the host-parasite system Microtus alvaris - Hymenolepis diminuta, Zn displays the highest accumulation coefficient, followed by those of Cu and Pb. The parasite showed a higher bioaccumulation compared to infected common voles, with the highest bioaccumulation found for Ni. ConclusionsThe bioaccumulation of trace metals depends on their mobility, concentration and chemical forms in water-soil solutions. Metal-organic species stimulate the phytoaccumulation of trace metals while inorganic ones suppress it. The sequence of trace metals bioaccumulation in common voles is analogous to that of soil contamination. The parasite exhibited higher bioaccumulation levels compared to infected common voles.

Common Vole as a Focal Small Mammal Species in Orchards of the Northern Zone

In 2018–2020, we performed a country-wide study of small mammals in commercial orchards and berry plantations with the aim of determining whether the common vole (Microtus arvalis) is a more suitable focal species than the field vole (M. agrestis) in the risk assessment of plant protection products in Lithuania (country of the Northern Zone). Common vole was present in 75% of orchards and in 80% of control habitats, accounting for 30% of all trapped individuals. The proportion of this species was stable between years and seasons. The pattern was in agreement with the intermediate disturbance hypothesis, i.e., highest in medium-aged crops, while lowest in habitats with high intensities of agricultural practices. The average relative abundance of common vole in autumn, 2.65 ± 0.52 individuals per 100 trap days, was three times higher than that in summer, with no differences recorded between crops and control habitats. Field vole was present in 30% of locations, only accounting for 2.1% of all trapped individuals. In central and eastern European countries, common vole is more widespread and abundant than field vole. In Lithuania, common vole dominates in orchards and natural habitats and is, therefore, the most relevant small mammal species for higher tier risk assessment.

Does Habitat Diversity Modify the Dietary and Reproductive Response to Prey Fluctuations in a Generalist Raptor Predator, the Eurasian Buzzard Buteo buteo?

Predators can modify their diet and demography in response to changes in food availability and habitat quality. I tested the prediction that some species can change their predation pattern, between specialist type and generalist type, depending on the complexity of habitat structure. It was hypothesized that their dietary response is stronger in diversified habitats than in simplified ones, but the opposite tendency occurs in the case of reproductive response. The nestling diet and breeding success of the Eurasian Buzzard Buteo buteo, the abundance of its main prey (the common vole Microtus arvalis), and that of the most important alternative prey group (passerines) were estimated over ten years in two types of agricultural habitat in western Poland, i.e., in the diversified habitat of small fields and the simplified habitat of large fields. The vole abundance was higher in large fields, but the abundance of passerines was greater in small fields. The frequency of voles in the Eurasian Buzzard nestling diet was higher in large fields than in small fields and increased with the abundance of this prey in crop fields. However, no difference in the relationship between the vole frequency in the diet of Eurasian Buzzards and the abundance of voles was found between the two habitat types. The breeding success of Eurasian Buzzards was dependent on the vole abundance, but this relationship did not differ between the two field types. It seems that the pattern of dietary and reproductive response of Eurasian Buzzards depends on the actual availability of individual prey species, which can be modified by habitat quality, rather than on relative prey abundance.

Hantavirus-Leptospira coinfections in small mammals from central Germany.

European orthohantaviruses (Puumala orthohantavirus (PUUV); Dobrava-Belgrade orthohantavirus (DOBV), genotype Kurkino; Tula orthohantavirus (TULV)), and Leptospira spp. are small mammal-associated zoonotic pathogens that cause diseases with potentially similar symptoms in humans. We investigated the frequency of Leptospira spp. and hantavirus single and double infections in small mammals from 22 sites in Thuringia, central Germany, during 2017. TULV infections were detected at 18 of 22 sites (mean prevalence 13.8%, 93/674). PUUV infections were detected at four of 22 sites (mean prevalence 1.5%, 7/471), and respective PUUV sequences formed a novel phylogenetic clade, but DOBV infections were not detected at all. Leptospira infections were detected at 21 of 22 sites with the highest overall prevalence in field voles (Microtus agrestis) with 54.5% (6/11) and common voles (Microtus arvalis) with 30.3% (205/676). Leptospira-hantavirus coinfections were found in 6.6% (44/671) of common voles but only in two of 395 bank voles. TULV and Leptospira coinfection probability in common voles was driven by individual (age) and population-level factors. Coinfections seemed to be particularly associated with sites where Leptospira spp. prevalence exceeded 35%. Future investigations should evaluate public health consequences of this strong spatial clustering of coinfections.

Incidence of alveolar echinococcosis in humans and animals in Kostanay region of the Republic of Kazakhstan

The research aims to study the spread of alveococcosis in humans and animals on the territory of the Kostanay region of the Republic of Kazakhstan. Studies on the diagnosis of alveococcosis in humans were conducted in the branch of the Ministry of Health of the Republic of Kazakhstan "Scientific-practical center of sanitary-epidemiological examination and monitoring", Kostanay, in 2010-2019. To determine the degree of invasion by alveococcosis, a pathoanatomic autopsy was performed on captured mouse-like rodents in the territory of the Kostanay region, where cases of human alveococcosis were registered. The incidence among the population of various age groups in the region was analyzed based on the results of blood samples by enzyme immunoassay (ELISA) and liver ultrasound. It is established that alveococcosis is a common disease among people living not only in the Kostanay region but also in the Republic of Kazakhstan in general. The main definitive hosts in the development cycle of the pathogen infestation on the territory of the Republic of Kazakhstan are foxes and dogs, intermediate hosts – 18 species of rodents, and for humans, alveococcosis is one of the most dangerous helminthic diseases, since in most cases it leads to death. Alveococcosis can be attributed to particularly dangerous infestations since the foci of infestation are formed not only in anthropogenic zones where the pathogen can devastate but also in natural biocenoses, where the main sources of the pathogen's spread in the external environment are foxes (Vulpes) and corsac foxes (Vulpes corsac). The maximum number of cases of alveococcosis in 2018-2020 was registered in intermediate hosts – mouse-like rodents, like common vole Microtus arvalis, the extent of A. multilocularis invasion was 3.1-3.5%. Based on the comparative analysis of the epizootic and epidemiological situation of alveococcosis in the territory of the Kostanay region, it should be noted that the risk of infection of the population with alveococcosis persists in all areas of the region.

What determines species composition and diversity of hypogeous fungi in the diet of small mammals? A comparison across mammal species, habitat types and seasons in Central European mountains

Interactions between diverse groups of organisms influence the functioning and diversity of ecosystems. Salient examples of such relationships are those among hypogeous fungi, trees and mycophagous mammals. To investigate the role of small mammals in transporting fungal spores within and outside forests as well as the influence of seasons, habitats and species on small mammal mycophagy, we set up a study in the Pieniny Mts, Western Carpathians (Southern Poland). The droppings of small mammals were collected during live trapping in July and September 2016 and 2017, to analyze richness, composition and frequency of fungal spores present in faeces. The yellow-necked mouse Apodemus flavicollis, the bank vole Myodes glareolus and the common vole Microtus arvalis were the most frequently trapped. Spores of 27 fungal taxa from 16 genera were retrieved from nearly 70% of faecal samples of rodents and shrews, with up to 9 spore taxa recorded per sample. Spore diversity in samples was higher in September than in July, although seasonal variation was year and animal dependent. The highest mean number of fungal taxa per sample was recorded for the bank vole and the yellow-necked mouse, with the former species showing a higher degree of mycophagy. The two rodents differed in the average frequencies of consumed fungi in samples, which could result from some degree of specialization in the choice of particular fungal species, as shown by the laboratory-based experiment. Within particular animal species, differences in the fungal diet were found between seasons. The spores of hypogeous fungi were transported from forests to meadows mostly by the yellow-necked mouse and, to a lesser extent, by the common vole. However, both, the diversity and the number of transported spores diminished with distance from the forest edge. • Rich and diverse assemblage of consumed hypogeous fungi in the Pieniny Mts. • Consumption of hypogeous fungi influenced by year, season, animal species and habitat. • Proves for a differential consumption of hypogeous fungi by rodent species. • Fungi are transported through the forest-meadow ecotone to the non-forest environments. • Yellow-necked mouse most effective in transporting fungal spores both in forests and in open areas.

Variation in the diet and breeding biology of the Common Barn-owl (Tyto alba) in a demographic cycle of Common Vole (Microtus arvalis) between two outbreaks×

Abstract In the present study, we analysed the variation of breeding parameters and the diet composition of the Common Barn-owl (Tyto alba) in three different demographic phases of the Common Vole (Microtus arvalis) in a complete population cycle between two outbreaks. The study was conducted in the south-eastern part of the Transdanubian region in South Hungary. For the analysis, we used data of 81 randomly selected first clutches from 2015 to 2019, a time period which represented a full demographic cycle of the Common Vole after the 2014 outbreak with an exceptionally high peak. We tested the impact of prey abundance and diversity of diet composition as continuous predictors as well as the demographic phase of Common Vole and the mesoregion as categorical explanatory variables on the measured reproductive outputs as response variables using Generalized Linear Models (GLM). Considering the breeding parameters, the number of fledglings, and fledging and reproductive success were significantly higher in the increase phase than during the vole crash phase. Based on GLM models, our results demonstrated that the clutch size of the Common Barn-owl is determined ultimately by the availability and consumption rate of the Common Vole as main prey, while other small mammal prey categories did not affect the clutch size. These results support the finding that the clutch size of vole-eating raptors and owls, which begin breeding periods in early spring predicts the vole abundance in this early spring period. Considering the other investigated small mammal prey groups, the alternative prey role was confirmed only in case of the Murid rodent prey categories (Apodemus spp., Muridae).

A Population-Based Approach to Determining the Borders and Number of Natural Plague Foci

A population-based approach to determining the borders and number of natural plague foci implies that the specialists in the field accept the concept that the existence of a natural plague focus is always provided by a single population of the main carrier. The discussion of this approach was motivated by the data collected in the course of a long-term study of the Hissar natural plague focus in Tajikistan. It was demonstrated that the area of this focus constitutes only 300 km2, and its functioning is maintained by a single relatively small population of Microtus carruthersi Thomas, 1909, the main plague carrier. The Hissar mountain range territories neighboring the focus have been surveyed for plague for more than 20 years. However, the plague pathogen (Yersinia pestis Lehmann, Neuman, 1986) could not be detected notwithstanding the absolute identity of the species composition of rodents and fleas. Many known natural plague foci are considerably larger in size than the Hissar focus and are inhabited by several populations of the main carrier. For example, five groups of populations of the common vole (Microtus arvalis Pallas, 1778), the main plague carrier, are described in the Eastern Caucasus high mountain focus occupying an area of 23 500 km2. In the Tuva mountain focus, the plague pathogen was found in six populations of the main carrier, the long-tailed ground squirrel (Spermophilus undulatus Pallas, 1778). On the territory of the Muyunkum desert natural plague focus occupying an area of 93 000 km2, 17 populations of the great gerbil (Rhombomys opimus Lichtenstein, 1823), the main plague carrier, are distinguished. Similar data are available for a number of other foci. Significantly, in different populations of the main carriers, the differences in the genotypes of both rodents and the plague pathogen were described, and asynchrony in plague epizootics could be traced. In such a way, the plague parasitic cenosis functioning within the borders and the habitation areal of a single population of the main carrier constitutes an autonomous standalone natural focus. Hence, the foci occupied by several populations of the main carrier are, in fact, groups of autonomous foci with a similar biocenotic structure. Therefore, a considerably larger number of natural (autonomous) foci are present within the plague natural focality zones than is commonly assumed.

Combined visual and biochemical analyses confirm depositor and diet for Neolithic coprolites from Skara Brae

Coprolites (fossilized faeces) can provide valuable insights into species’ diet and related habits. In archaeozoological contexts, they are a potential source of information on human-animal interactions as well as human and animal subsistence. However, despite a broad discussion on coprolites in archaeology, such finds are rarely subject to detailed examination by researchers, perhaps due to the destructive nature of traditional analytical methods. Here, we have examined coprolitic remains from the Neolithic (third millennium BCE) settlement at Skara Brae, Orkney, using a range of modern methods: X-ray computed tomography, scanning electron microscopy, lipid and protein analysis (shotgun proteomics of the coprolite matrix as well as collagen peptide mass fingerprinting of isolated bone fragments). This combined approach minimised destructiveness of sampling, leaving sufficient material for subsequent study, while providing more information than traditional morphological examination alone. Based on gross visual examination, coprolites were predominantly attributed to domestic dogs (Canis familiaris), with morphologically identified bone inclusions derived from domestic sheep (Ovis aries) and common voles (Microtus arvalis). Partial dissection of a coprolite provided bone samples containing protein markers akin to those of domestic sheep. Considering the predominance of vertebral and distal limb bone fragments, Skara Brae dogs were probably consuming human butchery or meal refuse, either routinely fed to them or scavenged. The presumably opportunistic consumption of rodents may also have played a role in pest control.

Among-individual differences in foraging modulate resource exploitation under perceived predation risk

Foraging is risky and involves balancing the benefits of resource acquisition with costs of predation. Optimal foraging theory predicts where, when and how long to forage in a given spatiotemporal distribution of risks and resources. However, significant variation in foraging behaviour and resource exploitation remain unexplained. Using single foragers in artificial landscapes of perceived risks and resources with diminishing returns, we aimed to test whether foraging behaviour and resource exploitation are adjusted to risk level, vary with risk during different components of foraging, and (co)vary among individuals. We quantified foraging behaviour and resource exploitation for 21 common voles (Microtus arvalis). By manipulating ground cover, we created simple landscapes of two food patches varying in perceived risk during feeding in a patch and/or while travelling between patches. Foraging of individuals was variable and adjusted to risk level and type. High risk during feeding reduced feeding duration and food consumption more strongly than risk while travelling. Risk during travelling modified the risk effects of feeding for changes between patches and resulting evenness of resource exploitation. Across risk conditions individuals differed consistently in when and how long they exploited resources and exposed themselves to risk. These among-individual differences in foraging behaviour were associated with consistent patterns of resource exploitation. Thus, different strategies in foraging-under-risk ultimately lead to unequal payoffs and might affect lower trophic levels in food webs. Inter-individual differences in foraging behaviour, i.e. foraging personalities, are an integral part of foraging behaviour and need to be fully integrated into optimal foraging theory.

Salmonella and Antimicrobial Resistance in Wild Rodents-True or False Threat?

Transmission of pathogenic and resistant bacteria from wildlife to the bacterial gene pool in nature affects the ecosystem. Hence, we studied intestine content of five wild rodent species: the yellow-necked wood mouse (Apodemus flavicollis, n = 121), striped field mouse (Apodemus agrarius, n = 75), common vole (Microtus arvalis, n = 37), bank vole (Myodes glareolus, n = 3), and house mouse (Mus musculus, n = 1) to assess their potential role as an antimicrobial resistance (AMR) and Salmonella vector. The methods adopted from official AMR monitoring of slaughtered animals were applied and supplemented with colistin resistance screening. Whole-genome sequencing of obtained bacteria elucidated their epidemiological relationships and zoonotic potential. The study revealed no indications of public health relevance of wild rodents from the sampled area in Salmonella spread and their limited role in AMR dissemination. Of 263 recovered E. coli, the vast majority was pan-susceptible, and as few as 5 E. coli showed any resistance. In four colistin-resistant strains neither the known mcr genes nor known mutations in pmr genes were found. One of these strains was tetracycline-resistant due to tet(B). High diversity of virulence factors (n = 43) noted in tested strains including ibeA, cdtB, air, eilA, astA, vat, pic reported in clinically relevant types of enteric E. coli indicate that rodents may be involved in the ecological cycle of these bacteria. Most of the strains represented unique sequence types and ST10805, ST10806, ST10810, ST10824 were revealed for the first time, showing genomic heterogeneity of the strains. The study broadened the knowledge on phylogenetic diversity and structure of the E. coli population in wild rodents.

Identification of a novel hantavirus strain in the root vole (Microtus oeconomus) in Lithuania, Eastern Europe.

Hantaviruses are zoonotic pathogens that can cause subclinical to lethal infections in humans. In Europe, five orthohantaviruses are present in rodents: Myodes-associated Puumala orthohantavirus (PUUV), Microtus-associated Tula orthohantavirus, Traemmersee hantavirus (TRAV)/ Tatenale hantavirus (TATV)/ Kielder hantavirus, rat-borne Seoul orthohantavirus, and Apodemus-associated Dobrava-Belgrade orthohantavirus (DOBV). Human PUUV and DOBV infections were detected previously in Lithuania, but the presence of Microtus-associated hantaviruses is not known. For this study we screened 234 Microtus voles, including root voles (Microtus oeconomus), field voles (Microtus agrestis) and common voles (Microtus arvalis) from Lithuania for hantavirus infections. This initial screening was based on reverse transcription-polymerase chain reaction (RT-PCR) targeting the S segment and serological analysis. A novel hantavirus was detected in eight of 79 root voles tentatively named "Rusne virus" according to the capture location and complete genome sequences were determined. In the coding regions of all three genome segments, Rusne virus showed high sequence similarity to TRAV and TATV and clustered with Kielder hantavirus in phylogenetic analyses of partial S and L segment sequences. Pairwise evolutionary distance analysis confirmed Rusne virus as a strain of the species TRAV/TATV. Moreover, we synthesized the entire nucleocapsid (N) protein of Rusne virus in Saccharomyces cerevisiae. We observed cross-reactivity of antibodies raised against other hantaviruses, including PUUV, with this new N protein. ELISA investigation of all 234 voles detected Rusne virus-reactive antibodies exclusively in four of 79 root voles, all being also RNA positive, but not in any other vole species. In conclusion, the detection of Rusne virus RNA in multiple root voles at the same trapping site during three years and its absence in sympatric field voles suggests root voles as the reservoir host of this novel virus. Future investigations should evaluate host association of TRAV, TATV, Kielder virus and the novel Rusne virus and their evolutionary relationships.

Small mammals in the big city: Behavioural adjustments of non-commensal rodents to urban environments.

A fundamental focus of current ecological and evolutionary research is to illuminate the drivers of animals' success in coping with human-induced rapid environmental change (HIREC). Behavioural adaptations are likely to play a major role in coping with HIREC because behaviour largely determines how individuals interact with their surroundings. A substantial body of research reports behavioural modifications in urban dwellers compared to rural conspecifics. However, it is often unknown whether the observed phenotypic divergence is due to phenotypic plasticity or the product of genetic adaptations. Here, we aimed at investigating (a) whether behavioural differences arise also between rural and urban populations of non-commensal rodents; and (b) whether these differences result from behavioural flexibility or from intrinsic behavioural characteristics, such as genetic or maternal effects. We captured and kept under common environment conditions 42 rural and 52 urban adult common voles (Microtus arvalis) from seven subpopulations along a rural-urban gradient. We investigated individual variation in behavioural responses associated with risk-taking and exploration, in situ at the time of capture in the field and ex situ after 3months in captivity. Urban dwellers were bolder and more explorative than rural conspecifics at the time of capture in their respective sites (in situ). However, when tested under common environmental conditions ex situ, rural individuals showed little change in their behavioural responses whereas urban individuals altered their behaviour considerably and were consistently shyer and less explorative than when tested in situ. The combination of elevated risk-taking and exploration with high behavioural flexibility might allow urban populations to successfully cope with the challenges of HIREC. Investigating whether the observed differences in behavioural flexibility are adaptive and how they are shaped by additive and interactive effects of genetic make-up and past environmental conditions will help illuminate eco-evolutionary dynamics under HIREC and predict persistence of populations under urban conditions.

Survival time of Leptospira kirschneri on strawberries.

In the past decade, two leptospirosis outbreaks occurred among strawberry harvesters in Germany, with 13, and 45 reported cases respectively. In both outbreaks, common voles (Microtus arvalis) infected with Leptospira kischneri serovar Grippotyphosa were identified as the most likely outbreak source. In an univariate analysis, eating unwashed strawberries was identified as one of the risk factors associated with Leptospira infection. The aim of this study was to evaluate the survival time of L. kirschneri serovar Grippotyphosa on strawberries under varying conditions. Strawberries were spiked with 5x109 of both a laboratory reference strain (strain Moskva V) and an outbreak field strain (94-6/2007) of L. kirschneri serovar Grippotyphosa sequence type 110. Survival times were investigated in a fully crossed design with three incubation times (2h, 4h, 6h and 8h) and three temperatures (15°C, 21°C and 25°C) with three replicated for each condition. A wash protocol was developed and recovered Leptospira were determined by qPCR, dark field microscopy and culturing. Viable L. kirschneri of both the reference strain and the field strain were identified in all samples at 25°C and an incubation time of 2h, but only 1/9 (11%) and 4/9 (44%) of the samples incubated at 15°C were positive, respectively. Both reference and field strain were viable only in 2/9 (22%) at 25° after 6h. After an 8h incubation, viable Leptospira could not be identified on the surface of the strawberries or within the fruit for any of the tested conditions. Based on these results, the exposure risk of consumers to viable Leptospira spp. through the consumption of strawberries bought at the retail level is most likely very low. However, there is a potential risk of Leptospira infection by consumption of strawberries on pick-your-own farms.

Assessing Genome-Wide Diversity in European Hantaviruses through Sequence Capture from Natural Host Samples.

Research on the ecology and evolution of viruses is often hampered by the limitation of sequence information to short parts of the genomes or single genomes derived from cultures. In this study, we use hybrid sequence capture enrichment in combination with high-throughput sequencing to provide efficient access to full genomes of European hantaviruses from rodent samples obtained in the field. We applied this methodology to Tula (TULV) and Puumala (PUUV) orthohantaviruses for which analyses from natural host samples are typically restricted to partial sequences of their tri-segmented RNA genome. We assembled a total of ten novel hantavirus genomes de novo with very high coverage (on average >99%) and sequencing depth (average >247×). A comparison with partial Sanger sequences indicated an accuracy of >99.9% for the assemblies. An analysis of two common vole (Microtus arvalis) samples infected with two TULV strains each allowed for the de novo assembly of all four TULV genomes. Combining the novel sequences with all available TULV and PUUV genomes revealed very similar patterns of sequence diversity along the genomes, except for remarkably higher diversity in the non-coding region of the S-segment in PUUV. The genomic distribution of polymorphisms in the coding sequence was similar between the species, but differed between the segments with the highest sequence divergence of 0.274 for the M-segment, 0.265 for the S-segment, and 0.248 for the L-segment (overall 0.258). Phylogenetic analyses showed the clustering of genome sequences consistent with their geographic distribution within each species. Genome-wide data yielded extremely high node support values, despite the impact of strong mutational saturation that is expected for hantavirus sequences obtained over large spatial distances. We conclude that genome sequencing based on capture enrichment protocols provides an efficient means for ecological and evolutionary investigations of hantaviruses at an unprecedented completeness and depth.