Microtus Pennsylvanicus Research Articles

Adaptive responses to habitat change: Theory and tests with field experiments.

Habitat loss and change are often implicated as the primary causes of species extinction. Although any population can be instantly imperiled by catastrophe, most habitat loss occurs gradually, thus enabling affected individuals an adaptive advantage to occupy the best of their dwindling opportunities. I demonstrate how to infer the advantage between two habitats for any density and frequency-dependent strategy of habitat selection. I explore the concept of an Adaptive Dispersal Strategy Landscape to reveal the Evolutionarily Stable Strategy separately for ideal-free and ideal preemptive habitat selectors. Both solutions reveal an initially counterintuitive expectation that individuals living at high density gain insufficient adaptive advantage to disperse from a deteriorating habitat. Adaptive dispersal is constrained at high density because habitats of better quality are fully occupied. I test the theory with measures of movement and foraging in crossover experiments on a seminatural population of meadow voles. The experiment allowed the voles to choose among patches and between enclosures in which I differentially manipulated food and shelter. Although photographs from an infrared camera documented voles venturing from one habitat to the other, none became resident. Voles preferentially foraged in the richer of the two enclosures, even when I reversed treatments, and they foraged more in patches protected by mulched straw. The adaptive advantage of dispersal using a surrogate fitness proxy based on the voles' giving-up densities mirrored that generated by theory. The convergence between theory and experiment yields much-needed insight into our ability to test, predict, and hopefully resolve, the ecological, evolutionary, and conservation consequences of habitat loss.

Rodent Gut Bacteria Coexisting with an Insect Gut Virus in Tapeworm Parasitic Cysts: Metagenomic Evidence of Microbial Selection in Extra-Intestinal Clinical Niches.

In medicine, parasitic cysts (e.g., brain cysticerci) are believed to be sterile, and are primarily treated with antiparasitic medications, not antibiotics, which could prevent abscess formation and localized inflammation. This study quantified the microbial composition of parasitic cysts in a wild rodent, using multi-kingdom metagenomics to comprehensively assess if parasitic cysts are sterile, and further understand gut microbial translocation and adaptation in wildlife confined environments, outside the gut. Analysis was conducted on DNA from two hepatic parasitic cysts from a feline tapeworm, Hydatigera (Taenia) taeniaeformis, affecting a wild vole mouse (Microtus pennsylvanicus), and from feces, liver and peritoneal fluid of this and two other concurrent individual wild voles trapped during pest control in one of our university research vegetable gardens. Bacterial metagenomics revealed the presence of gut commensal/opportunistic species, Parabacteroides distasonis, Bacteroides (Bacteroidota); Klebsiella variicola, E. coli (Enterobacteriaceae); Enterococcus faecium and Lactobacillus acidophilus (Bacillota) inhabiting the cysts, and peritoneal fluid. Remarkably, viral metagenomics revealed various murine viral species, and unexpectedly, a virus from the insect armyworm moth (Pseudaletia/Mythimna unipuncta), known as Mythimna unipuncta granulovirus A (MyunGV-A), in both cysts, and in one fecal and one peritoneal sample from the other non-cyst voles, indicating the survival and adaption potential of the insect virus in voles. Metagenomics also revealed a significantly lower probability of fungal detection in cysts compared to that in peritoneal fluid/feces (p < 0.05), with single taxon detection in each cyst (Malassezia and Pseudophaeomoniella oleicola). The peritoneal fluid had the highest probability for fungi. In conclusion, metagenomics revealed that bacteria/viruses/fungi coexist within parasitic cysts supporting the potential therapeutic benefits of antibiotics in cystic diseases, and in inflammatory microniches of chronic diseases, such as Crohn's disease gut wall cavitating micropathologies, from which we recently isolated similar synergistic pathogenic Bacteroidota and Enterobacteriaceae, and Bacillota.

Restored Wetland Size and Age Influence Small Mammal Communities in West Virginia, USA

Small mammals are important, albeit often overlooked, fauna in wetland restoration projects. However, it is essential to evaluate factors that influence small mammal community metrics in restored wetlands to maximize wetland restoration effectiveness. Previous studies found that vegetation differed as restored wetlands aged and that wetland age may play a role in the presence of amphibians and birds. Therefore, we assessed whether wetland age influenced small mammals. We also evaluated 17 environmental factors in restored wetlands that could influence small mammal communities in these wetlands. To assess and evaluate the effects of age and environmental factors on the small mammal community, we appraised 14 restored wetlands in West Virginia, USA, in the summers of 2020 and 2021 for small mammal community metrics, specifically relative abundance, diversity, richness, and evenness. We captured six species of small mammals: deer mice (Peromyscus maniculatus), white-footed mice (Peromyscus leucopus), meadow voles (Microtus pennsylvanicus), meadow jumping mice (Zapus hudsonius), northern short-tailed shrews (Blarina brevicauda), and eastern chipmunks (Tamias striatus). We found that the relative abundance of deer mice, white-footed mice, and meadow voles decreased with wetland age. However, both species diversity and evenness increased with wetland age. Wetland size influenced the relative abundance of white-footed mice, meadow jumping mice, and all small mammals combined. Although the relative abundance of white-footed mice and total small mammals decreased with wetland size, the relative abundance of meadow jumping mice increased with wetland size. Wetland managers should consider wetland age and size when designing wetlands to facilitate small mammal communities.

Population fluctuations of meadow voles (Microtus pennsylvanicus) in a landscape with cumulative clearcutting

Population fluctuations of meadow voles (Microtus pennsylvanicus) in a landscape with cumulative clearcutting

Comparative analysis of gonadal hormone receptor expression in the postnatal house mouse, meadow vole, and prairie vole brain

The socially monogamous prairie vole (Microtus ochrogaster) and promiscuous meadow vole (Microtus pennsylvanicus) are closely related, but only prairie voles display long-lasting pair bonds, biparental care, and selective aggression towards unfamiliar individuals after pair bonding. These social behaviors in mammals are largely mediated by steroid hormone signaling in the social behavior network (SBN) of the brain. Hormone receptors are reproducible markers of sex differences that can provide more information than anatomy alone and can even be at odds with anatomical dimorphisms. We reasoned that behaviors associated with social monogamy in prairie voles may emerge in part from unique expression patterns of steroid hormone receptors in this species, and that these expression patterns would be more similar across males and females in prairie than in meadow voles or the laboratory mouse. To obtain insight into steroid hormone signaling in the developing prairie vole brain, we assessed expression of estrogen receptor alpha (Esr1), estrogen receptor beta (Esr2), and androgen receptor (Ar) within the SBN, using in situ hybridization at postnatal day 14 in mice, meadow, and prairie voles. We found species-specific patterns of hormone receptor expression in the hippocampus and ventromedial hypothalamus, as well as species differences in the sex bias of these markers in the principal nucleus of the bed nucleus of the stria terminalis. These findings suggest the observed differences in gonadal hormone receptor expression may underlie species differences in the display of social behaviors.

Small mammals of a northern salt-affected grassland

Abstract While many studies have characterized small mammals of the southern and central Great Plains (USA), far fewer have documented small mammals of the northern Great Plains which differ dramatically in plant structure and composition. We examined the presence and distribution of small mammals captured at a salinity-affected grassland in northeastern North Dakota (2018–2021). We captured 12 species from 8 genera including Microtus pennsylvanicus (n = 724), Peromyscus (maniculatus) sonoriensis (n = 114), Sorex cinereus (n = 54), and Zapus hudsonius (n = 43). We evaluated the extent to which these species varied with plant and environmental characteristics. M. pennsylvanicus was positively associated with plant cover and soil moisture and P. (maniculatus) sonoriensis was positively associated with forb cover and negatively associated with litter and elevation. Z. hudsonius was negatively associated with forb cover and soil moisture and S. cinereus was positively associated with cover and negatively associated with salinity. These species associated with their environments differently than their more southern counterparts and reinforce the notion that not all areas, even in relatively intact grasslands, are available to all species. Future studies are needed to further examine more infrequently captured species, including a Sorex hoyi, an Onychomys leucogaster, and eight Myodes gapperi in this region.

Cell Proliferation and Cell Death Levels in the Dentate Gyrus Correlate with Home Range Size Among Adult Male Meadow Voles

Neurogenesis occurs throughout adulthood within the dentate gyrus, and evidence indicates that these new neurons play a critical role in both spatial and social memory. However, a vast majority of past research on adult neurogenesis has involved experiments with captive mice and rats, making the generalizability of results to natural settings questionable. We assessed the connection between adult neurogenesis and memory by measuring the home range size of wild-caught, free-ranging meadow voles (Microtus pennsylvanicus). Adult male voles (n = 18) were captured, fitted with radio collars, and released back into their natural habitat, where each vole’s home range was assessed using 40 radio-telemetry fixes over the course of 5 evenings. Voles were then recaptured, and brain tissue was collected. Cellular markers of cell proliferation (pHisH3, Ki67), neurogenesis (DCX), and pyknosis were labeled on histological sections and then quantified using either fluorescent or light microscopy. Voles with larger home ranges had significantly higher pHisH3+ cell densities within the granule cell layer and subgranular zone (GCL + SGZ) of the dentate gyrus and higher Ki67+ cell densities in the dorsal GCL + SGZ. Voles with larger ranges also had significantly higher pyknotic cell densities in the entire GCL + SGZ and in the dorsal GCL + SGZ. These results support the hypothesis that cell proliferation and cell death within the hippocampus are involved with spatial memory formation. However, a marker of neurogenesis (DCX+) was not correlated with range size, suggesting that there may be selective cellular turnover in the dentate gyrus when a vole is ranging through its environment.

A test of the social behavior network reveals differential patterns of neural responses to social novelty in bonded, but not non-bonded, male prairie voles

The social behavior network (SBN) has provided a framework for understanding the neural control of social behavior. The original SBN hypothesis proposed this network modulates social behavior and should exhibit distinct patterns of neural activity across nodes, which correspond to distinct social contexts. Despite its tremendous impact on the field of social neuroscience, no study has directly tested this hypothesis. Thus, we assessed Fos responses across the SBN of male prairie voles (Microtus ochrogaster). Virgin/non-bonded and pair bonded subjects were exposed to a sibling cagemate or pair bonded partner, novel female, novel male, novel meadow vole, novel object, or no stimulus. Inconsistent with the original SBN hypothesis, we did not find profoundly different patterns of neural responses across the SBN for different contexts, but instead found that the SBN generated significantly different patterns of activity in response to social novelty in pair bonded, but not non-bonded males. These findings suggest that non-bonded male prairie voles may perceive social novelty differently from pair bonded males or that SBN functionality undergoes substantial changes after pair bonding. This study reveals novel information about bond-dependent, context-specific neural responsivity in male prairie voles and suggests that the SBN may be particularly important for processing social salience. Further, our study suggests there is a need to reconceptualize the framework of how the SBN modulates social behavior.

Diet of a threatened rattlesnake (eastern massasauga) revealed by DNA metabarcoding.

Characterizing the diet of imperiled species using minimally invasive methods is crucial to understanding their ecology and conservation requirements. Here, we apply a DNA metabarcoding approach to study the diet of the eastern massasauga rattlesnake (Sistrurus catenatus), a Federally Threatened snake found throughout the Great Lakes region. Eighty-three fecal samples collected across 10 different massasauga populations located in Michigan, USA, were sequenced, with 70 samples containing prey DNA. We used universal metazoan primers and developed a host-specific oligonucleotide blocker to characterize their diet. We identified at least 12 different prey species, with eastern massasaugas exhibiting opportunistic feeding and a strong preference towards small mammals. Meadow voles (Microtus pennsylvanicus) were the most common prey item (70% of diet) followed by the northern short-tailed shrew (Blarina brevicauda) and masked shrew (Sorex cinereus; 15.7% of diet each), along with occasional bird and snake prey. Adult individuals exhibited a more generalized diet, consuming a larger number of prey taxa on average. Younger snakes consumed a smaller variety of prey items and tended to consume smaller-sized mammals such as masked shrews (Sorex cinereus) and northern short-tailed shrews (Blarina brevicauda). We conclude that small mammals are a crucial part of eastern massasauga rattlesnake diet and recommend this be taken into consideration when conservation strategies are developed. The methods developed in this study can be applied to other reptile species, providing an accurate, minimally invasive, and thorough diet assessment for at-risk reptile species.

An experimental analysis of density dependence in meadow voles: Within-season and delayed effects.

Wild mammal populations exhibit a variety of dynamics, ranging from fairly stable with little change in population size over time to high-amplitude cyclic or erratic fluctuations. A persistent question in population ecology is why populations fluctuate as they do. Answering this seemingly simple question has proven to be challenging. Broadly, density-dependent feedback mechanisms should allow populations to grow at low density and slow or halt growth at high density. However, experimental tests of what demographic processes result in density-dependent feedback and on what timescale have proven elusive. Here, we used replicated density perturbation experiments and capture-mark-recapture analyses to test density-dependent population growth in populations of meadow voles (Microtus pennsylvanicus) during the summer breeding season by manipulating founding population density and observing the pattern of survival, reproduction, and population growth. High population density had no consistent effect on survival rates but generally negatively influenced recruitment and population growth rates. However, these density-dependent effects varied within the breeding season and across years. Our study provides evidence that density-dependent feedback mechanisms operate at finer time scales than previously believed and that process, additively with delayed year effects, is key to understanding multiyear population demography.

Disentangling morphology and genetics in two voles (Microtus pennsylvanicus and M. ochrogaster) in a region of sympatry.

Species in recent, rapid radiations can be difficult to distinguish from one another due to incomplete sorting of traits, insufficient time for novel morphologies to evolve, and elevated rates of hybridization and gene flow. The vole genus Microtus (58 spp.) is one such system where all three factors are likely at play. In the central United States, the prairie vole, Microtus ochrogaster, and the eastern meadow vole, M. pennsylvanicus, occur in sympatry and can be distinguished on the basis of molar cusp patterns but are known to be exceptionally difficult to distinguish using external morphological characters. Using a combination of morphometrics, pelage color analyses, and phylogenetics, we explored which traits are most effective for species identification and whether these same traits can be used to identify the subspecies M. o. ohionensis. While we were able to identify six traits that differed significantly between M. ochrogaster and M. pennsylvanicus, we also found substantial measurement overlap which limits the utility of these traits for species identification. The subspecies M. o. ohionensis was particularly difficult to distinguish from M. p. pennsylvanicus, and we did not find any evidence that this subspecies forms a distinct genetic clade. Furthermore, the full species M. ochrogaster and M. pennsylvanicus did not form reciprocal clades in phylogenetic analyses. We discuss several possible reasons for these patterns, including unrecognized variation in molar cusp patterns and/or localized hybridization. Overall, our results provide useful information that will aid in the identification of these species and subspecies in the future, and provides a case study of how genetics, morphometrics, and fur color analyses can be used to disentangle signatures of evolutionary history and hybridization.

Is chronic stress a causal mechanism for small mammal population cycles? Reconciling the evidence.

Chronic stress has long been hypothesized to play a role in driving population cycles. Christian (1950) hypothesized that high population density results in chronic stress and mass "die-offs" in small mammal populations. Updated variations of this hypothesis propose that chronic stress at high population density may reduce fitness, reproduction, or program aspects of phenotype, driving population declines. We tested the effect of density on the stress axis in meadow voles (Microtus pennsylvanicus) by manipulating population density in field enclosures over three years. Using fecal corticosterone metabolites as a non-invasive measure of glucocorticoid (GC) concentrations, we found that density alone was not associated with GC differences. However, we found that the seasonal relationship of GC levels differed by density treatment, with high-density populations having elevated GC levels early in the breeding season and decreasing towards late summer. We additionally tested hippocampal glucocorticoid receptor and mineralocorticoid receptor gene expression in juvenile voles born at different densities, with the hypothesis that high density may reduce receptor expression, altering negative feedback of the stress axis. We found that females had marginally higher glucocorticoid receptor expression at high density, no effect in males, and no detectable effect of density on mineralocorticoid receptor expression in either sex. Hence, we found no evidence that high density directly impairs negative feedback in the hippocampus, butrather female offspring may be better equipped for negative feedback. We compare our findings with prior studies to attempt to disentangle the complicated relationship between density, seasonality, sex, reproduction and the stress axis.

Sex‐dependent habitat selection modulates risk management by meadow voles

AbstractForaging involves a trade‐off between food and safety. Most research into the trade‐off invokes safety from predation. But danger and its associated risk arise from multiple causes that cannot be assessed solely with reference to predators. A more complete assessment of risk management requires experimental designs that attempt to modify and measure risks, regardless of the source of danger. I aimed to do so by adding shelter (mulched straw) and time‐varying supplemental food (rabbit chow), while measuring foraging behavior and habitat use by a seminatural population of meadow voles. Voles foraged more intensely under safety, recognized least risk when given access to both food and shelter, but altered their risk management through time: management included a novel form of sex‐dependent habitat selection in which male–male pairs occupied risky areas without shelter while female–female pairs occupied habitats sheltered by straw. The pattern is consistent with a sex‐dependent evolutionary game in which female territoriality and tolerance of other females limit conflict with, and space use by, males. Voles' array of interacting strategies demonstrates that ecologists must be wary of ascribing risk only to predation, and particularly so if experiments are blind to other dangers and processes that alter foraging behavior and habitat selection.

Impact of food availability and predator cues on meadow vole response to social vs. non-social odorants

Abstract The risk of predation and food deprivation may alter the degree to which animals associate with conspecifics. We examined if food deprivation, the risk of predation, or simultaneous exposure to both altered meadow voles’ preference for odour cues in a way that adheres to the terminal investment, safety in numbers, or avoidance hypotheses. Satiated or food-deprived meadow voles were given the choice to investigate either opposite-sex conspecific bedding, same-sex conspecific bedding, clean bedding, or self-bedding when exposed to mink urine or olive oil. Mink urine and food deprivation did not impact the amount of time meadow voles spent with each type of bedding, but meadow voles did begin investigating more quickly when experiencing either or both stressors. However, food deprivation and mink urine did not have an additive impact on any measured variable. Further research is needed to determine if the terminal investment hypothesis is the hypothesis that best describes the mating behaviour of meadow voles facing one or multiple stressors.

Combining deep sequencing and conventional molecular approaches reveals broad diversity and distribution of fleas and Bartonella in rodents and shrews from Arctic and Subarctic ecosystems

BackgroundBartonella are intracellular bacteria that are transmitted via animal scratches, bites and hematophagous arthropods. Rodents and their associated fleas play a key role in the maintenance of Bartonella worldwide, with > 22 species identified in rodent hosts. No studies have addressed the occurrence and diversity of Bartonella species and vectors for small mammals in Arctic and Subarctic ecosystems, which are increasingly impacted by invasive species and climate change.MethodsIn this study, we characterized the diversity of rodent fleas using conventional PCR targeting the mitochondrial cytochrome c oxidase II gene (COII) and Bartonella species in rodents and shrews (n = 505) from northern Canada using conventional PCR targeting the ITS (intergenic transcribed spacer) region and gltA (citrate synthase) gene. Metagenomic sequencing of a portion of the gltA gene was completed on a subset of 42 rodents and four rodent flea pools.ResultsYear, total summer precipitation the year prior to sampling, average minimum spring temperature and small mammal species were significant factors in predicting Bartonella positivity. Occurrence based on the ITS region was more than double that of the gltA gene and was 34% (n = 349) in northern red-backed voles, 35% (n = 20) in meadow voles, 37% (n = 68) in deer mice and 31% (n = 59) in shrews. Six species of Bartonella were identified with the ITS region, including B. grahamii, B. elizabethae, B. washoensis, Candidatus B. rudakovii, B. doshiae, B. vinsonii subsp. berkhoffii and subsp. arupensis. In addition, 47% (n = 49/105) of ITS amplicons had < 97% identity to sequences in GenBank, possibly due to a limited reference library or previously unreported species. An additional Bartonella species (B. heixiaziensis) was detected during metagenomic sequencing of the gltA gene in 6/11 rodents that had ITS sequences with < 97% identity in GenBank, highlighting that a limited reference library for the ITS marker likely accounted for low sequence similarity in our specimens. In addition, one flea pool from a northern red-backed vole contained multiple species (B. grahamii and B. heixiaziensis).ConclusionOur study calls attention to the usefulness of a combined approach to determine the occurrence and diversity of Bartonella communities in hosts and vectors.Graphical

Community Structure of Terrestrial Vertebrates in a Restored Meadow Habitat in Pennsylvania: Assessing the Potential Prey Base for Eastern Massasauga Rattlesnakes

We sampled the vertebrate community of a 20-ha conservation easement in Venango County, PA, from April through August 2021. The restoration and management efforts on this easement were designed to improve the meadow habitat for one of the few remaining populations of Sistrurus catenatus (Eastern Massasauga Rattlesnake) in Pennsylvania, and our sampling efforts were focused on evaluating the potential prey base available to the rattlesnakes at this site. We identified 9 amphibian species, 10 reptile species, and 11 small mammal species. For amphibians, Anaxyrus americanus (American Toad) was the most abundant species, accounting for 32.6% of the total, followed by Notophthalmus viridescens (Red-Spotted Newt) with 30.6% of total abundance. Thamnophis brachystoma (Short-Headed Gartersnake) comprised more than half (53.7%) of all reptiles sampled, followed by Thamnophis sirtalis (Eastern Gartersnake; 22.7%). Peromyscus leucopus (White-Footed Mouse) was the most abundant mammal species, accounting for 37.4% of all mammals surveyed, followed by Microtus pennsylvanicus (Eastern Meadow Vole; 24.8%). Mammals had the greatest species richness (S = 11), while reptiles had the greatest total abundance (TA = 361), and amphibians had the greatest species evenness (E = 0.799). Species accounts for Venango County indicate that we sampled 40.9% (9/22), 37.0% (10/27), and 21.2% (11/52) of the known amphibian, reptilian, and mammalian species, respectively, within this restored meadow habitat. Our results suggest that the restoration efforts on this easement study site have been extremely effective in creating meadow habitat that supports a diversity of prey species for the Eastern Massasauga Rattlesnake.

Long-Term Changes in Abundance and Composition of Forest-Floor Small Mammal Communities in a Landscape with Cumulative Clearcutting

Responses of forest-floor small mammals to clearcutting are species-specific with generalists occupying a range of habitats, and specialists persisting on clearcuts for variable periods. We investigated the responses in abundance and species composition of small mammal communities to cumulative clearcutting of coniferous forests on a landscape that had four independent clearcutting events (Periods 1 to 4) over a 42-year interval from 1979 to 2020 in south-central British Columbia, Canada. We ask if the small mammal communities have changed significantly over these decades owing to removal of old-growth forest by clearcut harvesting. Hypotheses (H) predicted that the small mammal community would (H1) increase in abundance, species richness, and diversity on new clearcuts owing to the availability of early seral post-harvest habitats from cumulative clearcutting; and (H2) have higher mean abundance, species richness, and species diversity in clearcut than uncut forest sites, owing to availability of vegetative food and cover. A third hypothesis (H3) predicted that abundance of (i) early seral vegetation (herbs and shrubs) and (ii) small mammal populations, will be greater in ungrazed clearcut sites than in those grazed by cattle (Bos taurus). Mean total numbers of small mammals on new clearcuts declined in Periods 3 and 4, and hence did not support the abundance part of H1. Much of this decline was owing to low numbers of the long-tailed vole (Microtus longicaudus) and meadow vole (M. pennsylvanicus). Two generalist species: the deer mouse (Peromyscus maniculatus) and northwestern chipmunk (Neotamias amoenus), contributed to high mean species richness and diversity in Periods 2 and 3 before these metrics declined in Period 4, and hence partly supported H1. The similarity in mean total numbers of small mammals in Periods 2 to 4 did not support the abundance prediction of H2 that total numbers would be higher in clearcut than uncut forest sites. Higher mean species richness (Periods 2 and 3) and diversity (Period 3) measurements on clearcut than forest sites, particularly in the early post-harvest years, did support these parts of H2. The vegetation part (i) of H3 was not supported for herbaceous plants but it was for shrubs. The small mammal part (ii) of H3 that populations would be higher in ungrazed than grazed clearcut sites was supported for abundance but not for species richness or diversity. The decline and near disappearance of both species of Microtus was possibly related to the reduction in plant community abundance and structure from grazing (at least for shrubs) and potentially from drought effects associated with climate change. Loss of microtines from these early seral ecosystems may have profound negative effects on various ecological functions and predator communities.

Relative efficiency of two models of snap traps for sampling boreal small mammals

AbstractSnap traps have long been a cost‐effective means of monitoring small mammal (&lt;60 g) diversity and abundance, particularly at larger spatial or temporal scales. Yet, studies on the relative efficiency of snap trap models are surprisingly rare in the literature. We assessed the relative efficacy of Victor Mouse and Woodstream Museum Special snap traps for sampling boreal small mammals. Paired traps were set for 2–3 nights at 40–50 trapping stations at each of 110 sites, for a total sampling effort of 28,910 trap nights. We captured 1,013 small mammals representing 13 species. Overall, Museum Special traps caught almost twice as many small mammals as Victor traps. There was no difference in the sex or age‐class of the overall capture in the 2 trap models. However, Museum Special traps were triggered without capturing a small mammal 31% more often than Victor traps. Results for the six most frequently captured species (Myodes rutilus, Microtus pennsylvanicus, Microtus oeconomus, Microtus xanthognathus, Peromyscus maniculatus, and Sorex cinereus) mirrored those for overall captures. Moreover, the percent of the total capture in Museum Special traps ranged between 57–80% for each of the above species, indicating species‐specific responses to trap type. Our data further demonstrate the superior ability of Museum Special traps to capture boreal small mammals compared to Victor traps, which is likely attributed to a more sensitive trigging mechanism. Implications of our results suggest caution when mixing trap models in monitoring programs, or when interpreting results obtained with different trap models. We encourage similar comparisons in different biomes with different small mammal assemblages as trap performance is likely species specific.

Postfire salvage logging alters impacts of recent wildfire on small mammal communities in summer

Abstract Wildfire is a natural ecosystem disturbance in forests in North America, yet fires are often at odds with human activity and affect the timber supply. Postfire salvage logging is common practice globally, but the impacts of salvage logging on wildlife, especially small mammal communities, remain unclear. We livetrapped small mammals to determine their population responses to wildfire and postfire salvage logging in central British Columbia, Canada. Postfire regenerating forest provided habitat for deer mice (Peromyscus maniculatus), southern red-backed voles (Myodes gapperi), and meadow voles (Microtus pennsylvanicus). Postfire salvage logging significantly reduced tree basal area and changed small mammal community structure by reducing southern red-backed vole populations and supporting mainly deer mice, a generalist species. Given the large scale and intensity of postfire salvage logging operations across the province, salvage logging has the potential to decrease vole populations and change small mammal communities across the province.

Is there a relationship between parental age and offspring sex ratios in meadow voles?

Abstract Deviations from a 50:50 sex ratio by producing either more sons or daughters can provide fitness benefits for the parents. This is especially true for species where one sex has skewed reproductive success, in most cases males. The factors responsible for these shifts are not fully understood, but some relationships have been uncovered such as parental age. We looked for a potential relationship between the parental age of meadow voles and offspring sex ratios using a captive population. A trending linear relationship was found with paternal age and a significant quadratic relationship was found with maternal age. For males, older fathers tended to sire more sons compared to younger fathers which may be the result of selective forces of competition because of skewed reproductive success. For females, middle-aged mothers sired more sons compared to younger or older mothers. Middle age for a female could represent an optimal point for producing sons that are able to survive and compete with other males for reproductively available females.