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

Adiaspiromycosis is a nontransmissible infectious pulmonary disease caused by the inhalation of propagules from fungal species belonging to the family Ajellomicetaceae, especially Emergomyces crescens. Adiaspiromycosis caused by E. crescens has been recorded in a broad number of species worldwide, with small burrowing mammals being considered the main hosts for this environmental pathogen. Only a handful of studies on adiaspiromycosis in European wildlife has been published to date. We assessed the occurrence of adiaspiromycosis in wild rodents (Murinae and Arvicolinae) from the central Spanish Pyrenees (NE Spain). The lungs of 302 mice and 46 voles were screened for the presence of adiaspores through histopathologic examination. Pulmonary adiaspiromycosis was recorded in 21.6% of all individuals (75/348), corresponding to 63/299 wood mice (Apodemus sylvaticus) and 12/40 bank voles (Myodes glareolus). Adiaspore burden varied highly between animals, with a mean of 0.19 spores/mm2 and a percentage of affected lung tissue ranging from <0.01% to.8%. These results show that the infection is present in wild rodents from the central Spanish Pyrenees. Although the impact of this infection on nonendangered species is potentially mild, it might contribute to genetic diversity loss in endangered species. [ABSTRACT FROM AUTHOR]

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

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

Babesia microti is a tick-transmitted protozoan parasite of wildlife that can also cause serious disease in humans. It is now well established that B. microti represents an assemblage of different strains or species, only some of which are important zoonotic pathogens. Therefore, in order to assess the potential public health risk associated with B. microti in any given location, it is important to determine the strains that are present. This is the first study on the presence and identity of B. microti in Ireland. Overall, 314 wood mice (Apodemus sylvaticus), 243 bank voles (Myodes glareolus) and 634 questing Ixodes ricinus nymphs collected in various locations across Ireland were screened for the presence of B. microti by metabarcoding and nested PCR, respectively. Overall 8 rodent spleen samples (1.4%) were positive for B. microti, while all tick samples tested negative. Rodent isolates were identified as the ‘Munich’ strain which rarely causes human disease and is chiefly transmitted by the mouse tick, Ixodes trianguliceps. Together with reports from the UK these results suggest that B. microti does not represent a significant public health risk in Britain or Ireland.

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

We present a genome assembly from an individual male Apodemus sylvaticus (the wood mouse; Chordata; Mammalia; Rodentia; Muridae). The genome sequence is 2,889.8 megabases in span. Most of the assembly is scaffolded into 25 chromosomal pseudomolecules, including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 16.31 kilobases in length.

To prevent the non-acceptable effects of agrochemicals on arable fields, Environmental Risk Assessment (ERA) aims to assess and protect against a wide range of risks due to stressors to non-target species. While exposure to stress is a key factor in ERA models, exposure values are difficult to obtain and rely on laboratory studies with often debatable relevance to field situations. To improve intake estimates, data from realistic field-based scenarios are needed. We developed calibration curves relating known seed numbers of up to 20 onion and carrot seeds consumed by wild-caught wood mice (Apodemus sylvaticus) to the seed DNA content in the feces. Based on these inferred quantitative relationships, a field trial was run to determine seed intake in a natural setting using realistic levels of seed spillage. Onion DNA was detected in the fecal samples of the wood mice caught in the field, which resembled a seed intake of up to 1 onion seed. No intake of carrot seeds was detected. This is the first-ever study to quantify seed intake in a realistic field scenario using a DNA-based analysis, showing that accurate seed intake estimates can be obtained. Our approach can help to improve risk assessment models through its minimally-invasive and accurate assessment of seed intake by ERA representative and non-target species, which would otherwise be undetectable with traditional methods. Our novel approach and its results are highly relevant to studies of food intake and diet composition for basic and applied research alike.

Simple Summary: Elemental and stable isotope analyses are useful and common methods for wildlife diet studies, e.g., for characterizing diets and trophic relationships. However, little is known about the potential applicability of these techniques to address other aspects of feeding ecology. Here, we evaluated whether faecal elemental (carbon and nitrogen) and/or isotopic values (δ13C, δ15N) can determine variations in the amount of food intake. Overall, elemental analyses and δ15N values failed in reporting significant differences, but preliminary outcomes support the potential use of faecal δ13C values as an indicator to detect short-term slight food intake changes. The results of this work provide, for the first-time, reference data for interpreting faecal elemental and isotopic patterns in free-ranging wood mice (Apodemus sylvaticus), as well as new insights into the additional applicability of isotopic analysis in feeding ecology studies. The analysis of carbon and nitrogen elemental (C, N) and isotopic compositions (δ13C, δ15N) in faeces are considered reliable methodologies for the study of diet in wildlife. Here, we tested the suitability of these techniques to detect variations in the amount of food intake. We captured wild wood mice (Apodemus sylvaticus) with Sherman live traps where bait access was initially free, and later it was experimentally limited inside by four different devices to cause intended variations in the amount ingested. The total C and N (%) and stable δ13C and δ15N isotopic values were determined for the bait and in mice faecal samples. Faecal values were lower than bait ones except for N, likely due to animal matter ingested before capture. No significant differences in total C, N and δ13C were found due to individual traits. However, breeding males showed higher δ15N values than breeding females, probably due to differences in energy and protein demands between both sexes during the breeding season. Only δ13C detected food intake variations (≥2 g). Despite further research being needed, these results initially support the potential of δ13C to provide information on the amount ingested, thus being useful to complement trophic ecology studies. [ABSTRACT FROM AUTHOR]

Gastrointestinal (GI) helminths are common parasites of humans, wildlife, and livestock, causing chronic infections. In humans and wildlife, poor nutrition or limited resources can compromise an individual's immune response, predisposing them to higher helminth burdens. This relationship has been tested in laboratory models by investigating infection outcomes following reductions of specific nutrients. However, much less is known about how diet supplementation can impact susceptibility to infection, acquisition of immunity, and drug efficacy in natural host–helminth systems. We experimentally supplemented the diet of wood mice (Apodemus sylvaticus) with high-quality nutrition and measured resistance to the common GI nematode Heligmosomoides polygyrus. To test whether diet can enhance immunity to reinfection, we also administered anthelmintic treatment in both natural and captive populations. Supplemented wood mice were more resistant to H. polygyrus infection, cleared worms more efficiently after treatment, avoided a post-treatment infection rebound, produced stronger general and parasite-specific antibody responses, and maintained better body condition. In addition, when applied in conjunction with anthelmintic treatment, supplemented nutrition significantly reduced H. polygyrus transmission potential. These results show the rapid and extensive benefits of a well-balanced diet and have important implications for both disease control and wildlife health under changing environmental conditions. [ABSTRACT FROM AUTHOR]

Reproduction of wild rodents in the temperate regions is adaptively timed with the season under the influence of photoperiod, temperature and food availability. The aim of this study was to investigate the responses of three small-sized murine species to the same physical and ecological conditions in a locality of Great Kabylia (Algeria). Apodemus sylvaticus, and Mus spretus synchronized their reproduction in winter and spring, Lemniscomys barbarus in spring and summer. Photoperiod and temperature cannot explain this reproduction shift that might be linked to the feeding ecology of the species. [ABSTRACT FROM AUTHOR]

Un arbusto invasor influye negativamente en la dispersión de semillas autóctonas por roedores La competencia aparente mediada por refugio es el mecanismo por el que las plantas invasivas aumentan la presión sobre las autóctonas proporcionando un refugio para los consumidores generalistas. En el Reino Unido, la especie invasora Rhododendron ponticum no proporciona alimento a los consumidores generalistas de semillas, pero el dosel perenne ofrece refugio frente a roedores depredadores, y la depredación y el robo son los principales riesgos que afectan al comportamiento de alimentación y almacenamiento de los roedores. En el presente estudio, llevamos a cabo un experimento sobre la retirada y el destino de las semillas con objeto de entender cómo puede afectar la invasión de un arbusto perenne a la dispersión y el destino de las semillas y al reclutamiento temprano de árboles autóctonos. Utilizamos semillas de cuatro especies: semillas pequeñas y anemócoras (arce blanco Acer pseudoplatanus y fresno común Fraxinus excelsior) y semillas grandes y zoócoras (roble común Fraxinus excelsior y avellano común Corylus avellana) e hicimos el seguimiento de la predación y el almacenamiento de semillas en bosques abiertos, en hábitats de transición y debajo de Rhododendron. En los bosques abiertos, las semillas anemócoras tuvieron una mayor probabilidad de ser consumidas in situ que almacenadas, mientras que en las semillas zoócoras ocurrió lo contrario. Estas últimas se retiraron del bosque abierto y los hábitats de transición y se almacenaron debajo de Rhododendron. Esta pauta era la única esperable si el riesgo de predación era el factor más influyente en la decisión de consumir o almacenar las semillas. El aumento de la dispersión de las semillas hacia la cubierta de Rhododendron no hizo aumentar las perspectivas de supervivencia de las mismas, puesto que la densidad de las plántulas de avellano y roble debajo de la cubierta era prácticamente nula, a diferencia de lo que ocurre en el bosque abierto; un hecho se puede deberse al aumento del robo de las semillas almacenadas, a la baja supervivencia de las plántulas en condiciones de sombra densa o a ambas cosas. El aumento de la predación de semillas de fresno y arce cerca de la cubierta de Rhododendron también hizo disminuir el reclutamiento de estos árboles. Los parches de Rhododendron sesgaron el comportamiento de alimentación de los roedores hacia el lado negativo (predación neta) de la interacción condicional entre roedores y árboles. Es posible que este efecto influya en la regeneración de bosques autóctonos y facilite aún más la propagación de Rhododendron debido a la competencia aparente mediada por refugio.

We screened 526 wild small mammals for zoonotic viruses in northwest Spain and found hantavirus in common voles (Microtus arvalis) (1.5%) and high prevalence (48%) of orthopoxvirus among western Mediterranean mice (Mus spretus). We also detected arenavirus among small mammals. These findings suggest novel risks for viral transmission in the region.

Anthropogenic activities and natural events such as periodic tree masting can alter resource provisioning in the environment, directly affecting animals, and potentially impacting the spread of infectious diseases in wildlife. The impact of these additional resources on infectious diseases can manifest through different pathways, affecting host susceptibility, contact rate and host demography.To date however, empirical research has tended to examine these different pathways in isolation, for example by quantifying the effects of provisioning on host behaviour in the wild or changes in immune responses in controlled laboratory studies. Furthermore, while theory has investigated the interactions between these pathways, this work has focussed on a narrow subset of pathogen types, typically directly transmitted microparasites. Given the diverse ways that provisioning can affect host susceptibility, contact patterns or host demography, we may expect the epidemiological consequences of provisioning to vary among different parasite types, dependent on key aspects of parasite life history, such as the duration of infection and transmission mode.Focusing on an exemplar empirical system, the wood mouse Apodemus sylvaticus, and its diverse parasite community, we developed a suite of epidemiological models to compare how resource provisioning alters responses for a range of these parasites that vary in their biology (microparasite and macroparasite), transmission mode (direct, environmental and vector transmitted) and duration of infection (acute, latent and chronic) within the same host population.We show there are common epidemiological responses to host resource provisioning across all parasite types examined. In particular, the epidemiological impact of provisioning could be driven in opposite directions, depending on which host pathways (contact rate, susceptibility or host demography) are most altered by the addition of resources to the environment. Broadly, these responses were qualitatively consistent across all parasite types, emphasising the importance of identifying general trade‐offs between provisioning‐altered parameters.Despite the qualitative consistency in responses to provisioning across parasite types, we predicted notable quantitative differences between parasites, with directly transmitted parasites (those conforming to SIR and SIS frameworks) predicted to show the strongest responses to provisioning among those examined, whereas the vector‐borne parasites showed negligible responses to provisioning. As such, these analyses suggest that different parasites may show different scales of response to the same provisioning scenario, even within the same host population. This highlights the importance of knowing key aspects of host–parasite biology, to understand and predict epidemiological responses to provisioning for any specific host–parasite system. [ABSTRACT FROM AUTHOR]

DNA‐based approaches have greatly improved the applicability of dietary studies aimed at investigating ecological processes. These studies have provided direct insights into, otherwise difficult to measure, interactions between species and trophic levels, food web structure and ecosystem functioning. However, despite these advances, DNA‐based methods have struggled to accurately quantify the whole breadth of diet constituents because of methodological biases, such as amplification bias and digestive processes. The present study is, to our knowledge, the first diet study to use droplet digital PCR to quantify diet constituents. We manipulated the diet of wild‐caught wood mice (Apodemus sylvaticus) by feeding them with a known amount of small vegetable seeds (onion and carrot) and quantified the DNA traces of these diet constituents in faecal samples. The sensitivity of the technique combined with the control on the experimental design allowed mitigation of methodological bias. We were able to accurately determine DNA concentrations of small vegetable seeds in the diet of wood mice. Quantification of target DNA demonstrated significant differences in DNA content when one vs. five seeds were consumed. These differences remained significant when the age, sex and other diet constituents of the mice were altered. Different DNA markers, targeting different parts of the chloroplast, influenced onion DNA detectability. However, all onion and carrot markers showed higher DNA content for higher seed numbers. Overall, the sensitive DNA‐based approach developed in this study allows for minimally invasive quantification of small diet constituents in faeces, which would otherwise be undetectable with traditional methods. [ABSTRACT FROM AUTHOR]

Ixodes ricinus ticks transmit Borrelia burgdorferi sensu lato (s.l.) as well as Borrelia miyamotoi. Larvae become infected when feeding on infected rodents, with horizontal transmission of B. burgdorferi and horizontal and vertical transmission of B. miyamotoi. We studied seasonal dynamics of infection rates of I. ricinus and their rodent hosts, and hence transmission risk of these two distinctly different Borrelia species. Rodents were live-trapped and inspected for ticks from May to November in 2013 and 2014 in a forest in The Netherlands. Trapped rodents were temporarily housed in the laboratory and detached ticks were collected. Borrelia infections were determined from the trapped rodents and collected ticks. Borrelia burgdorferi s.l. and B. miyamotoi were found in ticks as well as in rodents. Rodent density was higher in 2014, whereas tick burden as well as the Borrelia infection rates in rodents were higher in 2013. The density of B. miyamotoi-infected nymphs did not differ between the years. Tick burdens were higher on Apodemus sylvaticus than on Myodes glareolus, and higher on males than on females. Borrelia-infection rate of rodents varied strongly seasonally, peaking in summer. As the larval tick burden also peaked in summer, the generation of infected nymphs was highest in summer. We conclude that the heterogeneity of environmental and host-specific factors affects the seasonal transmission of Borrelia spp., and that these effects act more strongly on horizontally transmitted B. burgdorferi spp. than on the vertically transmitted B. miyamotoi. [ABSTRACT FROM AUTHOR]

Abstract Background Fleas frequently infest small mammals and play important vectoring roles in the epidemiology of (re)emerging zoonotic disease. Rodent outbreaks in intensified agro-ecosystems of North-West Spain have been recently linked to periodic zoonotic diseases spillover to local human populations. Obtaining qualitative and quantitative information about the composition and structure of the whole flea and small mammal host coexisting communities is paramount to understand disease transmission cycles and to elucidate the disease-vectoring role of flea species. The aims of this research were to: (i) characterise and quantify the flea community parasiting a small mammal guild in intensive farmlands in North-West Spain; (ii) determine and evaluate patterns of co-infection and the variables that may influence parasitological parameters. Methods We conducted a large-scale survey stratified by season and habitat of fleas parasitizing the small mammal host guild. We report on the prevalence, mean intensity, and mean abundance of flea species parasitizing Microtus arvalis, Apodemus sylvaticus, Mus spretus and Crocidura russula. We also report on aggregation patterns (variance-to-mean ratio and discrepancy index) and co-infection of hosts by different flea species (Fager index) and used generalized linear mixed models to study flea parameter variation according to season, habitat and host sex. Results Three flea species dominated the system: Ctenophthalmus apertus gilcolladoi, Leptopsylla taschenbergi and Nosopsyllus fasciatus. Results showed a high aggregation pattern of fleas in all hosts. All host species in the guild shared C. a. gilcolladoi and N. fasciatus, but L. taschenbergi mainly parasitized mice (M. spretus and A. sylvaticus). We found significant male-biased infestation patterns in mice, seasonal variations in flea abundances for all rodent hosts (M. arvalis, M. spretus and A. sylvaticus), and relatively lower infestation values for voles inhabiting alfalfas. Simultaneous co-infections occurred in a third of all hosts, and N. fasciatus was the most common flea co-infecting small mammal hosts. Conclusions The generalist N. fasciatus and C. a. gilcolladoi dominated the flea community, and a high percentage of co-infections with both species occurred within the small mammal guild. Nosopsyllus fasciatus may show higher competence of inter-specific transmission, and future research should unravel its role in the circulation of rodent-borne zoonoses.

Forest management is increasingly focused on enhancing structural complexity. An increase in structural complexity is assumed to increase the abundance and diversity of fauna, including vertebrates. This faunal assemblage serves, in turn, as host community for a suite of vectors and their pathogens, so that structural complexity may cascade through a network of interactions in forest ecosystems. Here we use a network of 19 forest plots representing a gradient of structural complexity and dominant tree species (oak, beech, poplar) to test two hypotheses on the effect of structural complexity on the prevalence of tick-borne pathogens. Our first hypothesis is that tick densities will increase with increasing structural complexity, assuming that each life stage has higher chances of finding a suitable host. The second hypothesis is that the pathogen prevalence in ticks and small mammals decreases (cf. dilution hypothesis) or increases (cf. amplification hypothesis) with increasing structural complexity. These expectations are tested through a community-level analysis, looking at twelve pathogens: seven genospecies of Borrelia (B. afzelii, B. bavariensis, B. garinii, B. burgdorferi sensu stricto, B. spielmanii, B. valaisiana and B. miyamotoi) , Babesia s.s., Babesia microti, Anaplasma phagocytophilum, Rickettsia helvetica and Spiroplasma ixodetes. We found that more structurally complex forests have a higher density of questing nymphs (in June and July, during the peak of nymph activity). We did not find a clear change in pathogen prevalence with increasing structural complexity in ticks, wood mice and bank vole; the effect was different for the different pathogens and between the different dominant tree species. No clear co-occurrence patterns of pathogens were found. The density of infected nymphs and thus the disease risk is higher in more complex forests. A potential solution is to focus on decreasing the human-tick interactions in forests instead of trying to decrease the number of questing ticks. [Display omitted] • Forest management is progressively centering on increasing structural complexity. • Density of questing ticks is higher in more structural complex forests. • Pathogen prevalence does not change with increasing structural complexity. • Risk of tick-borne diseases is higher in more structural complex forests. [ABSTRACT FROM AUTHOR]

The analysis of carbon and nitrogen elemental (C, N) and isotopic compositions (δ13C, δ15N) in faeces are considered reliable methodologies for the study of diet in wildlife. Here, we tested the suitability of these techniques to detect variations in the amount of food intake. We captured wild wood mice (Apodemus sylvaticus) with Sherman live traps where bait access was initially free, and later it was experimentally limited inside by four different devices to cause intended variations in the amount ingested. The total C and N (%) and stable δ13C and δ15N isotopic values were determined for the bait and in mice faecal samples. Faecal values were lower than bait ones except for N, likely due to animal matter ingested before capture. No significant differences in total C, N and δ13C were found due to individual traits. However, breeding males showed higher δ15N values than breeding females, probably due to differences in energy and protein demands between both sexes during the breeding season. Only δ13C detected food intake variations (≥2 g). Despite further research being needed, these results initially support the potential of δ13C to provide information on the amount ingested, thus being useful to complement trophic ecology studies.

Wood mouse Apodemus sylvaticus and striped field mouse A. agrarius are the most abundant mouse species in Central Europe coexisting in several habitats not only such as in forests but also in rural and urban areas. Their basic colours are similar, but the striped field mouse has a pronounced black stripe on its back. The biological function of this phenotypic difference is unexplored; therefore, our goal was to study the impact of fur pattern as well as the scent on the survival of these species. In our study, we used plasticine models mimicking wood mouse and striped field mouse. For imitating mouse scent, cotton pads saturated with mouse urine were placed under the models. In spring 2016, 200 plasticine mice divided into four types (non‐striped with scent, non‐striped without scent, striped with scent, striped without scent) were placed randomly in four sampling sites in the mid‐sized city, Pécs, Hungary. During 4 weeks of exposure, we recorded predation on 71 plasticine models. Birds (51%) and large mammals (25%) were the most common predators, and in 24% of the cases, the models disappeared. Considering predation only by large mammals, we found that the daily survival rate of both striped and non‐striped models with scent decreased in comparison to models without scent. Thus, large mammalian predators could discover plasticine models sooner than avian predators, which suggests a strong impact of scent. Despite the high rate of bird predation, we did not detect an effect of fur pattern suggesting that it may not be related to survival but might have other functional roles. With the dummy mouse experiment, we showed that fur pattern may play a minor role in mice detection by predators, thus further studies are needed to discover its ecological function. [ABSTRACT FROM AUTHOR]

Cryptosporidium spp. are worldwide protozoan parasites that can affect to a broad range of vertebrate hosts, including rodents. In the island of Corsica (France), there are no previous data about these protozoa infecting wild rodents. To estimate the distribution and occurrence, a total of 117 wild murine rodents of the species Rattus rattus (84), Mus musculus domesticus (21), Apodemus sylvaticus (11), and Rattus norvegicus (1) were captured in 24 different biotopes. Fecal samples were screened for Cryptosporidium spp. by nested PCR to amplify an 830 bp fragment of the 18S rRNA gene. As general occurrence, 15.4% of the rodents analyzed were positive for Cryptosporidium spp., being detected widely distributed along the island in R. rattus (17.6%) and M. m. domesticus (14.3%). Cryptosporidium viatorum, Cryptosporidium sp. rat genotype II, and Cryptosporidium sp. rat genotype III were successfully identified in R. rattus. The results herein reported provide the first data on Cryptosporidium spp. in wild murine species from a Mediterranean island and constitute the first report of the zoonotic species C. viatorum in R. rattus. Although a low occurrence of Cryptosporidium spp. in murids was obtained and only in one animal the zoonotic species C. viatorum was identified, our results highlight that wild murine rodents from Corsica could mediate in the maintenance and transmission of this protozoan to the environment and other hosts including humans and animals. Further studies are required to better understand the epidemiology of Cryptosporidium spp. in wild rodents from Corsica and their possible public health repercussions. [ABSTRACT FROM AUTHOR]

Abstract Background Mice of the genus Apodemus are one the most common mammals in the Palaearctic region. Despite their broad range and long history of ecological observations, there are no whole-genome data available for Apodemus, hindering our ability to further exploit the genus in evolutionary and ecological genomics context. Results Here we present results from the double-digest restriction site-associated DNA sequencing (ddRAD-seq) on 72 individuals of A. flavicollis and 10 A. sylvaticus from four populations, sampled across 500 km distance in northern Poland. Our data present clear genetic divergence of the two species, with average p-distance, based on 21377 common loci, of 1.51% and a mutation rate of 0.0011 - 0.0019 substitutions per site per million years. We provide a catalogue of 117 highly divergent loci that enable genetic differentiation of the two species in Poland and to a large degree of 20 unrelated samples from several European countries and Tunisia. We also show evidence of admixture between the three A. flavicollis populations but demonstrate that they have negligible average population structure, with largest pairwise F ST

To date, few studies of parasite epidemiology have investigated ‘who acquires infection from whom’ in wildlife populations. Nonetheless, identifying routes of disease transmission within a population, and determining the key groups of individuals that drive parasite transmission and maintenance, are fundamental to understanding disease dynamics. Gammaherpesviruses are a widespread group of DNA viruses that infect many vertebrate species, and murine gammaherpesviruses (i.e. MuHV-4) are a standard lab model for studying human herpesviruses, for which much about the pathology and immune response elicited to infection is well understood. However, despite this extensive research effort, primarily in the lab, the transmission route of murine gammaherpesviruses within their natural host populations is not well understood. Here, we aimed to understand wood mouse herpesvirus (WMHV) transmission, by fitting a series of population dynamic models to field data on wood mice naturally infected with WMHV and then estimating transmission parameters within and between demographic groups of the host population. Different models accounted for different combinations of host sex (male/female), age (subadult/adult) and transmission functions (density/frequency-dependent). We found that a density-dependent transmission model incorporating explicit sex groups fitted the data better than all other proposed models. Male-to-male transmission was the highest among all possible combinations of between- and within-sex transmission classes, suggesting that male behaviour is a key factor driving WMHV transmission. Our models also suggest that transmission between sexes, although important, wasn’t symmetrical, with infected males playing a significant role in infecting naïve females but not vice versa. Overall this work shows the power of coupling population dynamic models with long-term field data to elucidate otherwise unobservable transmission processes in wild disease systems.

ABSTRACT A curated murine oral microbiome database to be used as a reference for mouse-based studies has been constructed using a combination of bacterial culture, 16S rRNA gene amplicon, and whole-genome sequencing. The database comprises a collection of nearly full-length 16S rRNA gene sequences from cultured isolates and draft genomes from representative taxa collected from a range of sources, including specific-pathogen-free laboratory mice, wild Mus musculus domesticus mice, and formerly wild wood mouse Apodemus sylvaticus. At present, it comprises 103 mouse oral taxa (MOT) spanning four phyla—Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes—including 12 novel undescribed species-level taxa. The key observations from this study are (i) the low diversity and predominantly culturable nature of the laboratory mouse oral microbiome and (ii) the identification of three major murine-specific oral bacterial lineages, namely, Streptococcus danieliae (MOT10), Lactobacillus murinus (MOT93), and Gemella species 2 (MOT43), which is one of the novel, still-unnamed taxa. Of these, S. danieliae is of particular interest, since it is a major component of the oral microbiome from all strains of healthy and periodontally diseased laboratory mice, as well as being present in wild mice. It is expected that this well-characterized database should be a useful resource for in vitro experimentation and mouse model studies in the field of oral microbiology. IMPORTANCE Mouse model studies are frequently used in oral microbiome research, particularly to investigate diseases such as periodontitis and caries, as well as other related systemic diseases. We have reported here the details of the development of a curated reference database to characterize the oral microbial community in laboratory and some wild mice. The genomic information and findings reported here can help improve the outcomes and accuracy of host-microbe experimental studies that use murine models to understand health and disease. Work is also under way to make the reference data sets publicly available on a web server to enable easy access and downloading for researchers across the world.

Gastrointestinal (GI) helminths are common parasites of humans, wildlife, and livestock, causing chronic infections. In humans and wildlife, poor nutrition or limited resources can compromise an individual's immune response, predisposing them to higher helminth burdens. This relationship has been tested in laboratory models by investigating infection outcomes following reductions of specific nutrients. However, much less is known about how diet supplementation can impact susceptibility to infection, acquisition of immunity, and drug efficacy in natural host–helminth systems. We experimentally supplemented the diet of wood mice (Apodemus sylvaticus) with high-quality nutrition and measured resistance to the common GI nematode Heligmosomoides polygyrus. To test whether diet can enhance immunity to reinfection, we also administered anthelmintic treatment in both natural and captive populations. Supplemented wood mice were more resistant to H. polygyrus infection, cleared worms more efficiently after treatment, avoided a post-treatment infection rebound, produced stronger general and parasite-specific antibody responses, and maintained better body condition. In addition, when applied in conjunction with anthelmintic treatment, supplemented nutrition significantly reduced H. polygyrus transmission potential. These results show the rapid and extensive benefits of a well-balanced diet and have important implications for both disease control and wildlife health under changing environmental conditions. [ABSTRACT FROM AUTHOR]

Background: Fleas frequently infest small mammals and play important vectoring roles in the epidemiology of (re)emerging zoonotic disease. Rodent outbreaks in intensified agro-ecosystems of North-West Spain have been recently linked to periodic zoonotic diseases spillover to local human populations. Obtaining qualitative and quantitative information about the composition and structure of the whole flea and small mammal host coexisting communities is paramount to understand disease transmission cycles and to elucidate the disease-vectoring role of flea species. The aims of this research were to: (i) characterise and quantify the flea community parasiting a small mammal guild in intensive farmlands in North-West Spain; (ii) determine and evaluate patterns of co-infection and the variables that may influence parasitological parameters. Methods: We conducted a large-scale survey stratified by season and habitat of fleas parasitizing the small mammal host guild. We report on the prevalence, mean intensity, and mean abundance of flea species parasitizing Microtus arvalis, Apodemus sylvaticus, Mus spretus and Crocidura russula. We also report on aggregation patterns (variance-to-mean ratio and discrepancy index) and co-infection of hosts by different flea species (Fager index) and used generalized linear mixed models to study flea parameter variation according to season, habitat and host sex. Results: Three flea species dominated the system: Ctenophthalmus apertus gilcolladoi, Leptopsylla taschenbergi and Nosopsyllus fasciatus. Results showed a high aggregation pattern of fleas in all hosts. All host species in the guild shared C. a. gilcolladoi and N. fasciatus, but L. taschenbergi mainly parasitized mice (M. spretus and A. sylvaticus). We found significant male-biased infestation patterns in mice, seasonal variations in flea abundances for all rodent hosts (M. arvalis, M. spretus and A. sylvaticus), and relatively lower infestation values for voles inhabiting alfalfas. Simultaneous co-infections occurred in a third of all hosts, and N. fasciatus was the most common flea co-infecting small mammal hosts. Conclusions: The generalist N. fasciatus and C. a. gilcolladoi dominated the flea community, and a high percentage of co-infections with both species occurred within the small mammal guild. Nosopsyllus fasciatus may show higher competence of inter-specific transmission, and future research should unravel its role in the circulation of rodent-borne zoonoses. [ABSTRACT FROM AUTHOR]

The distributions of the nematode parasites Heligmosomoides polygyrus and Syphacia stroma were quantified in three equal-length sections along the intestine of wood mice (Apodemus sylvaticus) trapped in three different locations in the south of England. The distribution of H. polygyrus did not change in the presence of S. stroma, this species being largely confined to the anterior third of the intestine, whether S. stroma was or was not present. However, while in single infections with S. stroma, worms were equally distributed in the anterior and middle sections of the intestine, in the presence of H. polygyrus, a higher percentage of worms was located in the middle section. This was a dose-dependent response by S. stroma to increasing worm burdens with H. polygyrus, and even relatively low intensities of infection with H. polygyrus (e.g. ≤10 worms) were sufficient to cause a posterior redistribution of S. stroma into the middle section. A similar posterior shift in the percentage distribution of S. stroma in the intestine was evident in juvenile and mature mice of both sexes, and in mice from all three study sites. The ecological significance of these results is discussed. [ABSTRACT FROM AUTHOR]

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

Very little information exists on the growth rates of woodland rodents and the drivers of body size dynamics that are observed in British populations. In this study, we use mark–recapture data collected on two species living in sympatry, wood mice (Apodemus sylvaticus) and bank voles (Myodes glareolus). A third species of rodent, the yellow‐necked mouse (Apodemus flavicollis) was also caught occasionally. We found the density of this third species negatively impacted the growth rate of both wood mice and bank voles. No impact of conspecific population density on growth for either species was found. Previous studies have suggested high conspecific population density can impact growth for some individuals of the population, but our populations may have not reached the densities required to elucidate these effects during the study. [ABSTRACT FROM AUTHOR]

Body mass in wild animals has been suggested to be regulated by the opposing fitness consequences of variation in body size (and fat storage) for starvation and predation risk. Many studies of adult mammals and birds have broadly confirmed the predictions of this model. However, relatively few studies have addressed the potential role of such trade‐offs during early phases of development when animals are growing. Similarly, studies of the impact of high‐fat diets on wild small mammals generally show a resistance to weight gain. But whether growing animals are similarly resistant is unclear. In this study, weaned wood mice (Apodemus sylvaticus) were exposed to a high risk of predation, simulated by the broadcasting of owl calls, for 66 days during which body mass and energy intake were monitored. We hypothesized that if the risk of predation plays a role in regulating body mass during this phase then animals growing under predation risk would grow less. We found female (but not male) mice exposed to the predation risk treatment had lower growth rates and ended the experiment lighter; however, variations in energy intake and resting metabolic rate did not explain the observed differences. Feeding on high‐fat diet resulted in individuals with higher body mass. Females reached their adult size earlier than males and were more responsive to the predation risk treatment when feeding on high‐fat diet. Our data suggest males body mass to have fitness consequences on social dominance and reproductive success not accounted for in the simple starvation‐predation trade‐off model. [ABSTRACT FROM AUTHOR]

The role of helminths of the wood mouse, Apodemus sylvaticus, as biological indicators of the post-fire regeneration process in Serra Calderona Natural Park, a Mediterranean forest ecosystem located between the provinces of València and Castelló (Valencian Country, Spain), has been analysed for almost twenty years. The helminth ecological analysis of 917 A. sylvaticus (675 originating from the burned area and 242 originating from the control area) has been carried out between the 2nd and 18th post-fire years. The influence of intrinsic (host population density, sex and age) and extrinsic (site, period and year of capture, climate variables) factors on the post-fire evolution of the helminth community of the wood mouse, and the biodiversity, species richness and life cycle of the helminth species was studied. Taking into account the most important results obtained, various aspects of the helminth community dynamics of the wood mouse are confirmed as biological indicators of the post-fire regeneration process in Mediterranean ecosystems. The still existing differences between the two areas are mainly related to the influence of climate variables on the post-fire regeneration process. Moreover, the important role that helminth parasites of the wood mouse play as biological indicators of this process in Mediterranean ecosystems is demonstrated.

Acorn crops and rodent populations [bank vole (Myodes glareolus), yellow-necked mouse (Apodemus flavicollis), and wood mouse (Apodemus sylvaticus)] were monitored for 11 years (2002–2012) in mature oak commercial forests in South Moravia (the Czech Republic). Large acorn crops, marking so-called seed years, were recorded in 2003, 2006, 2009, 2010, and 2011. Acorn crops were repeated with period of 3–4 years. The abundance of all three species correlated positively with size of the acorn crop in the previous year. However, significant relationship between the size of the crop and grow of the population was found only in Apodemus flavicollis. Probably because of its food specialty, this species was most affected by acorn crops. Acorn crops had an effect on the breeding season of all monitored rodent species. In autumn of the seed years, the breeding period was prolonged in both Apodemus species; on the contrary, the crop had no major impact on bank voles. The higher the crop, the earlier A. flavicollis began to reproduce in the spring and the sooner it reached its peak and end of reproduction in a given year. The beginning, peak, and end of reproduction were significantly later in bank vole than in Apodemus spp. Lower North Atlantic Oscillation index (i.e. higher temperatures in the vegetation season and lower during winter, "NAO" hereinafter) was more suitable for Apodemus flavicollis. Higher values of the wNAO (winter NAO index) had a positive impact on Apodemus spp. while bank voles were not affected by this. [ABSTRACT FROM AUTHOR]

In Europe, ticks are major vectors of both human and livestock pathogens (e.g. Lyme disease, granulocytic anaplasmosis, bovine babesiosis). Agricultural landscapes, where animal breeding is a major activity, constitute a mosaic of habitat types of various quality for tick survival and are used at different frequencies by wild and domestic hosts across seasons. This habitat heterogeneity, in time and space, conditions the dynamics of these host-vector-pathogen systems and thus drives acarological risk (defined as the density of infected ticks). The principal objective of the OSCAR project (2011-2016) was to examine the links between this heterogeneity and acarological risk for humans and their domestic animals. Here, we present the data associated with this project. [ABSTRACT FROM AUTHOR]

Background: Mice of the genus Apodemus are one the most common mammals in the Palaearctic region. Despite their broad range and long history of ecological observations, there are no whole-genome data available for Apodemus, hindering our ability to further exploit the genus in evolutionary and ecological genomics context. Results: Here we present results from the double-digest restriction site-associated DNA sequencing (ddRAD-seq) on 72 individuals of A. flavicollis and 10 A. sylvaticus from four populations, sampled across 500 km distance in northern Poland. Our data present clear genetic divergence of the two species, with average p-distance, based on 21377 common loci, of 1.51% and a mutation rate of 0.0011 - 0.0019 substitutions per site per million years. We provide a catalogue of 117 highly divergent loci that enable genetic differentiation of the two species in Poland and to a large degree of 20 unrelated samples from several European countries and Tunisia. We also show evidence of admixture between the three A. flavicollis populations but demonstrate that they have negligible average population structure, with largest pairwise FST<0.086. Conclusion: Our study demonstrates the feasibility of ddRAD-seq in Apodemus and provides the first insights into the population genomics of the species. [ABSTRACT FROM AUTHOR]

• The bioinvasion of Myodes glareolus in Ireland presents a unique study system of host and parasite. • Seasonality and the stage of the invasion should be included when investigating parasite dynamics during a bio-invasion. • The concurrent study of invasive and native hosts and careful identification of their parasite communities is required. • These factors allow the identification of the dynamic processes influencing the parasite component and intra community. One of the primary drivers of emerging infectious diseases (EIDs) is human intervention via host or parasite translocations. A unique opportunity to study host and parasite dispersal during a bio-invasion currently exists in Ireland due to the introduction of the bank vole (Myodes glareolus) in the 1920s. The continuing range expansion of M. glareolus within Ireland presents a natural large-scale perturbation experiment. This study used the Irish M. glareolus model to conduct a spatiotemporal study analysing the parasite dynamics of native and invasive species throughout their range. Myodes glareolus and native Apodemus sylvaticus were trapped in woodlands across Ireland and surveyed for their helminth parasites. Myodes glareolus in Ireland were found to have lower parasite diversity in comparison to records of M. glareolus from across Europe and A. sylvaticus in Ireland. Increased density of M. glareolus resulted in a dilution effect, with significantly lower levels of parasitism overall in native hosts, where M. glareolus has been established longest. However, three helminth parasite species of A. sylvaticus increased in abundance in the presence of M. glareolus. Furthermore, M. glareolus at the expansion front were less parasitised (lower abundance and prevalence of certain parasites and lower parasite diversity) than M. glareolus from the core population. This "enemy release" is believed to be mediating the continued successful spread of the invader across Ireland. Our results identify two important variables, seasonality and the stage of the invasion, which should not be overlooked when investigating or managing the changing distribution of hosts and their parasites. Studies of bio-invasions and parasite transmission have primarily focused on the invasive host species or the native host species in cases where virulent pathogen spillover is observed. Our results demonstrate how the concurrent study of invasive and native hosts, and the careful identification of their parasite communities, allows the dynamic processes influencing the parasite component and intracommunity to be identified. [ABSTRACT FROM AUTHOR]

Agriculture and pastureland for cattle grazing are common land uses in Mediterranean landscapes. These activities significantly alter the habitat conditions, affecting the body conditions of wild communities, especially those with low vagility, such as small mammals. We aimed to evaluate how cattle grazing and the habitat composition affected the body condition of the wood mouse Apodemus sylvaticus in a southern Mediterranean agroforestry system using the Scale Mass Index (SMI) as an indicator of individuals condition. To assess variation in body condition, wood mice were live-trapped in a gradient of grazed sites with different stocking intensities, as well in sites excluded to grazing at different time periods (1998, 2004, and 2008). Wood mice body conditions were influenced by both microhabitat and macrohabitat drivers, with sex-biased patterns, while for the females, only the shrub species had an influence (a microhabitat variable); for the males, both the shrub species and the undercover density (and specifically their interaction) were the important drivers (microhabitat and macrohabitat variables). Unexpectedly, the physical condition variation detected between periods was not directly proportional to the exclusion period, but rather, a certain degree of similarity was found between the different sites (sites excluded since 2004 paired with grazed sites). These results suggest that the presence of food and shelter are determinants to the wood mouse's physical condition: for females, securing food sources enhance the body condition, while for males, the degree of cover, and consequently refuge against predators, seems to be determinant. These results reinforce the need for sustainable landscape management to assure the maintenance of habitat heterogeneity. [ABSTRACT FROM AUTHOR]

Small mustelids such as weasels are highly specialized predators of small rodents. Their diminutive size allows hunting for prey underground, but also means that they are "bite-sized" predators, preyed upon by other larger predators. Habitat use by weasels is therefore expected to depend not only on prey abundance, but also on predation risk. We report here on the body size and habitat use of common weasels Mustela nivalis vulgaris captured in intensive farmlands of northwest Spain during 2009–2015. We show that weasels' capture rate was higher in field margins than in other habitats (cereal and alfalfa fields, fallows) irrespective of season. All small mammals (common vole, wood mouse, Algerian mouse, and greater white-toothed shrew) were consistently more frequently captured in field margins than other habitats. Weasel capture rate in each habitat was proportional to that of prey in these (alfalfa > fallows > cereal), except for field margins, which were used more intensively than expected from prey capture rate. Weasel capture rate was 37% lower in areas provided with nest boxes to increase local raptor abundance, a reduction that occurred in all habitats and was significant when correcting for prey capture rate. Weasel habitat use reflected a trade-off between prey abundance (bottom-up control) and predation risk (top-down control), with a preferential use of field margins that offer not only more prey but also permanent vegetation cover and protection from avian predators throughout most of the annual crop cycles. Weasel and vole head width data show that voles are not safe underground from smaller female weasels and that burrow entrances were wide enough for weasels to escape underground from predators. In NW Spain, common voles are a main farmland pest causing significant impacts. We discuss the implications of current vole control measures for weasels in areas recurrently affected by vole outbreaks. [ABSTRACT FROM AUTHOR]

The influence of age and sex on the bioaccumulation of heavy metals in Apodemus sylvaticus was studied in Merja Zerga lagoon in northern Morocco. Five trace metal elements (Zn, Pb, Cr, Cu and Fe) were quantitatively analyzed by Varian AA 240 atomic absorption spectroscopy with graphite furnace in three organs (Liver, Kidney and Heart) from animals of different age and sex. The maximum metal level of the analyzed samples was recorded in adults and was limited to 46.62 μg/g for Pb and 35.1 μg/g for Cu, while it reached 22.69 μg/g, 7.59 μg/g and 6.78 μg/g for Cr, Zn and Fe, respectively. Highly significant differences were found for bioaccumulation of heavy metals according to animal ages and no significant differences were observed between the two sexes among the studied animals. Our results revealed also the existence of a strong correlation (r > 0.65) between the majority of biometric parameters and the trace element concentrations. In general, we found that age is a critical factor in estimating the level of heavy metal pollution. Other characteristics such as habitat, feeding habits and anti-predator behavior of the species need to be studied. [ABSTRACT FROM AUTHOR]

Babesia microti is a tick-transmitted protozoan parasite of wildlife that can also cause serious disease in humans. It is now well established that B. microti represents an assemblage of different strains or species, only some of which are important zoonotic pathogens. Therefore, in order to assess the potential public health risk associated with B. microti in any given location, it is important to determine the strains that are present. This is the first study on the presence and identity of B. microti in Ireland. Overall, 314 wood mice (Apodemus sylvaticus), 243 bank voles (Myodes glareolus) and 634 questing Ixodes ricinus nymphs collected in various locations across Ireland were screened for the presence of B. microti by metabarcoding and nested PCR, respectively. Overall 8 rodent spleen samples (1.4%) were positive for B. microti , while all tick samples tested negative. Rodent isolates were identified as the 'Munich' strain which rarely causes human disease and is chiefly transmitted by the mouse tick, Ixodes trianguliceps. Together with reports from the UK these results suggest that B. microti does not represent a significant public health risk in Britain or Ireland. [ABSTRACT FROM AUTHOR]

We present a genome assembly from an individual male Apodemus sylvaticus (the wood mouse; Chordata; Mammalia; Rodentia; Muridae). The genome sequence is 2,889.8 megabases in span. Most of the assembly is scaffolded into 25 chromosomal pseudomolecules, including the X and Y sex chromosomes. The mitochondrial genome has also been assembled and is 16.31 kilobases in length., Competing Interests: No competing interests were disclosed., (Copyright: © 2023 Knowles SCL et al.)

In most mammals with seasonal reproduction, males undergo testis regression during the non-breeding period. We performed a morphological, hormonal, functional, and molecular study of the testes of sexually inactive males of two species of murine rodents, the wood mouse, Apodemus sylvaticus, and the Algerian mouse, Mus spretus, in syntopic populations of southern Iberian peninsula. Both species reproduce during most of the year, but wood mice stop breeding in the summer whereas Algerian mice do it in winter. Sexually inactive males of A. sylvaticus show complete testis regression with reduced levels of serum testosterone and abnormal distribution of cell-adhesion molecules. Contrarily, inactive males of M. spretus maintain almost normal spermotogenesis despite a significant reduction of androgenic function. The lack of an evident explanation for the divergent seasonal breeding patterns found in southern populations of A. sylvaticus and M. spretus, compared with northern ones, implies that very subtle species/population-specific features and/or non-conspicuous environmental cues probably operate to determine their seasonal breeding pattern. These results also support the notion that multiple models of circannual testis variation are possible for different populations of the same species, showing that the mechanisms controlling seasonal reproduction are in fact very plastic and fast evolving.

Elevation is one of the most important natural gradients that is strongly shaping communities across relatively small areas. However, few studies have followed the temporal dynamics of elevational patterns, even in organisms for which population and community fluctuations have been extensively studied, such as rodents. Here we report the multiannual dynamics of small-mammal communities along an elevational gradient in the Southern Carpathians. During a 5-year survey, we conducted live-trapping in forested and shrubby habitats, at elevations between 820 and 2040 m. We used partial constrained multivariate analysis and mixed-effects models to test the effect of elevation, year, and their interaction. Community metrics differed significantly between even and odd years and temporal changes had stronger effect on small-mammal communities than elevation. The 2-year pattern of dynamics was especially marked in the yellow-necked field mouse (Apodemus flavicollis (Melchior, 1834)). Species abundance was predicted not only by year and elevation, but also by their interaction. The dominant rodent species, the bank vole (Myodes glareolus (Schreber, 1780)) and A. flavicollis, showed opposite annual patterns in relation to elevation, possibly as a strategy to avoid competition. Failure to consider the fluctuations in montane small-mammal communities may lead to wrong assessment of species' state and distribution. [ABSTRACT FROM AUTHOR]

The predation and dispersal of seeds by scatter-hoarding animals is one of the most studied processes in the context of animal–plant interactions. Seed management by these animals has been traditionally approached at the population level: the patterns documented in the field are assumed to be similar for all individuals of the population and the variability within the population is considered to be random noise. However, little is known about to what extent this variability responds to different and consistent behaviours between individuals. The aim of this study was to analyse the individual variation and consistency in behaviour of scatter-hoarding rodents within a population. As our model we used the wood mouse, Apodemus sylvaticus , a key disperser of holm oak acorns, Quercus ilex , which, in turn, suffers high predation pressure by the common genet, Genetta genetta. In two sets of laboratory experiments, we compared the variance and consistency in behaviours and acorn management due to individual differences with that due to manipulation, using genet scents, of the perceived predation risk. Genet scents reduced the activity (i.e. time out of the refuge) in all wood mice, but the differences and consistency in activity between individuals accounted for most of the variance. Also, mice showed different and consistent stress or relaxed behaviours. Most of the variance in seed management variables, such as dispersal distance and seed size selection, was explained by consistent differences between individuals across scent treatments. The increase in stress behaviours and decrease in relaxed behaviours were positively related to dispersal ability (i.e. longer distances and larger acorns). Our study highlights the importance of considering the individual component of behaviour in scatter-hoarding rodents. This fine-scale level, largely overlooked in the ecological framework, will help to increase our understanding of seed management by scatter-hoarding animals. Highlights • We analysed the individual variation in behaviour by scatter-hoarding rodents. • The perceived predation risk was manipulated to assess the consistency of behaviour. • Individual differences explained more than 80% of total behavioural variance. • Rodents showed an extraordinary consistency in their individual behaviour. • We highlight the relevance of individual behaviour in scatter-hoarding animals. [ABSTRACT FROM AUTHOR]

Thermoregulation, metabolism and life history of species are affected by body size and shape. Based on specimens of the wood mouse Apodemus sylvaticus that were collected at Doñana National Park in 1978–81 and 2006–07, we tested for changes between these periods in body mass, body size, and allometry. Furthermore, we used data from 1978–81, when more specimens were available, to evaluate the sexual dimorphism of adults. Between the two periods and regardless of age, the most striking reduction in size in both females and males concerned body mass (females −29.5%, males −36%) and ear length (−20% for both sexes). Although less pronounced (3–4%), we also found a significant reduction in the total cranial and the condyle-basal lengths of females but not of males. No change was evident for the zygomatic width and the diastema length and for the head-body and hind foot lengths in either sex. The allometric relationships between the measured traits and the head-body length in adults did not change between the two periods. Males were larger than females in all the measured traits except the zygomatic width and the ear length. No sexual dimorphism was evident relative to the static allometry of adults. We speculate that a major determinant of this reduction may have been a shortage in suitable resources. Overall, this study confirms and extends previous findings on male-biased sexual size dimorphism and reveals a dramatic decline in body mass, which is likely linked to the observed reduction in species abundance at Doñana. The extent and rapidity of the observed morphological changes raise concerns about the conservation of Doñana ecosystems and pose questions for future research on the ecological processes that caused these changes. [ABSTRACT FROM AUTHOR]

The extensive use of anticoagulant rodenticides (ARs) results in widespread unintentional exposure of non-target rodents and secondary poisoning of predators despite regulatory measures to manage and reduce exposure risk. To elucidate on the potential vectoring of ARs into surrounding habitats by non-target small mammals, we determined bromadiolone prevalence and concentrations in rodents and shrews near bait boxes during an experimental application of the poison for 2 weeks. Overall, bromadiolone was detected in 12.6% of all small rodents and insectivores. Less than 20 m from bait boxes, 48.6% of small mammals had detectable levels of bromadiolone. The prevalence of poisoned small mammals decreased with distance to bait boxes, but bromadiolone concentration in the rodenticide positive individuals did not. Poisoned small mammals were trapped up to 89 m from bait boxes. Bromadiolone concentrations in yellow-necked mice (Apodemus flavicollis) were higher than concentrations in bank vole (Myodes glareolus), field vole (Microtus agrestis), harvest mouse (Micromys minutus), and common shrew (Sorex araneus). Our field trials documents that chemical rodent control results in widespread exposure of non-target small mammals and that AR poisoned small mammals disperse away from bating sites to become available to predators and scavengers in large areas of the landscape. The results suggest that the unintentional secondary exposure of predators and scavengers is an unavoidable consequence of chemical rodent control outside buildings and infrastructures. [ABSTRACT FROM AUTHOR]

Wild populations are continuously subjected to changes in environmental factors that pose different challenges. Body condition and hormones have been commonly used as health indicators due to their potential correlation with fitness. In the present study, we analyzed whether habitats of different quality influenced body mass, food intake and physiological stress levels in wild wood mice (Apodemus sylvaticus). Field work was seasonally carried out in Holm oak woods and pine forests in central Spain. A total of 93 wood mice from 4 different populations (2 per habitat type) were live‐trapped. From each captured individual we noted body mass and food intake, measured as the amount of bait remaining in each trap. The physiological stress levels were measured non‐invasively in collected fresh feces by quantifying fecal corticosterone metabolites (FCM) with a 5a‐pregnane‐3ß,11ß, 21‐triol‐20‐one enzyme immunoassay. Wood mice abundances decreased from spring to summer, were higher in Holm oak woods than in pine forests and also resulted in different age‐class distribution between both habitats. Individuals inhabiting pine forests showed a lower body mass and increased food intake, probably because of the comparatively lower food quality and availability in this habitat. Furthermore, these individuals showed increased physiological stress levels, likely due to the lower quality habitat in relation to both food and vegetation cover availability. Overall, besides affecting local wood mouse abundance, our study underscores the effect of habitat quality on body mass, food intake and the endocrine stress response. Considering the wood mouse's pivotal position in ecosystems, these results could help in the understanding of environmental traits hampering the viability of wild populations. [ABSTRACT FROM AUTHOR]

A specimen of the yellow-necked wood mouse Apodemus flavicollis possessing a remarkably extensive neck collar was trapped in the Slavkovský les Protected Landscape Area in November 2018. Some additional specimens with similar colouration were found in collections of the Karlovy Vary Museum. Detailed examination of a large collection of skins revealed considerable variation in neck colouration ranging from a complete absence of the yellow spot to presence of a very extensive yellow collar. [ABSTRACT FROM AUTHOR]

Highlights • Mice recapture/total captures ratio is higher under predation risk. • Recaptured mice stress levels are lower in the presence of predator cues. • Under predation risk, the safety provided by traps may outweigh their risks. • The effects of two stressors do not result in the addition of both responses. Abstract Live trapping is an essential element of field ecological studies. However, the act of trapping provides two types of conditional benefits (food from the bait when hungry, and refuge from a predator when threatened) against one type of drawback (confinement). Our understanding of how animals assess the two benefits against the lone risk determines how we interpret classic field studies in chemical ecology and wildlife management. Here, we studied wood mice responses to these risks and rewards of field trapping by examining experience through recapture and faecal corticosterone metabolites (FCM) as a physiological response indicator. Wood mice were live-trapped in two different plots subjected to two distinct phases: phase 1, absence of predator cues, and phase 2, in which traps were treated with red fox faeces. During phase 1, the recapture percentage was lower indicating that mice avoided traps while FCM levels in recaptured mice were higher. On the contrary, during phase 2, despite the total number of captures was lower we found an increase in the recapture percentage and FCM levels did not increase in recaptured mice. Our results suggest that under increased risk perception traps could be likely considered as a suitable shelter and thus, for some individuals the benefits of traps may outweigh their risks. In addition, we discovered that the effects of combining two stressors do not result in the addition of the response originated by each factor separately. [ABSTRACT FROM AUTHOR]