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linking behavior, life history and food supply with the population dynamics of white-footed mice (peromyscus leucopus).in this paper we review and integrate key aspects of behavioral and life history traits, food supply and population dynamics of the white-footed mouse (peromyscus leucopus), a species that is abundant and widely distributed across much of eastern north america. results are based largely on a 33-year mark-and-recapture study in a forest fragment in northwest ohio, usa. behavioral plasticity in such reproductive traits as mating system and parental care allows this species to adjust quickly to cha ...200721396027
trophic shifts of a generalist consumer in response to resource pulses.trophic shifts of generalist consumers can have broad food-web and biodiversity consequences through altered trophic flows and vertical diversity. previous studies have used trophic shifts as indicators of food-web responses to perturbations, such as species invasion, and spatial or temporal subsidies. resource pulses, as a form of temporal subsidies, have been found to be quite common among various ecosystems, affecting organisms at multiple trophic levels. although diet switching of generalist ...201121437248
species differences in the winner effect disappear in response to post-victory testosterone manipulations.evolutionary processes can interact with the mechanisms of steroid hormone action to drive interspecific variation in behavioural output, yet the exact nature of these interactions is poorly understood. to investigate this issue, we compare the endocrine machinery underlying the winner effect (an ability to increase winning behaviour in response to past victories) in two closely related species of peromyscus mice. typically, after winning a fight, california mice (peromyscus californicus) experi ...201121490015
associations between ixodes scapularis ticks and small mammal hosts in a newly endemic zone in southeastern canada: implications for borrelia burgdorferi transmission.immature ixodes scapularis infestation and borrelia burgdorferi infection of wild small mammals were studied from june to october in 2007 and from may to october in 2008 at 71 study sites in a zone where i. scapularis populations and environmental lyme disease risk are emerging in southwestern quebec. seasonal host-seeking activity of immature i. scapularis was similar to patterns reported previously in canada and the usa: nymphal activity peaked in spring while larval activity peaked in late su ...201122108010
Habitat correlates with the spatial distribution of ectoparasites on Peromyscus leucopus in southern Michigan.The goal of this study was to evaluate the role of habitat in determining ectoparasite distribution of Peromyscus leucopus. We tested the hypothesis that ectoparasite occurrence is associated with particular host environments and this association is stronger for ectoparasites with limited interactions (i.e., ticks) than those with frequent interactions (i.e., lice). Ectoparasites from three different groups (Acari, Siphonaptera, and Phthiraptera) were collected from P. leucopus inhabiting a numb ...201122129402
partitioning the aggregation of parasites on hosts into intrinsic and extrinsic components via an extended poisson-gamma mixture model.it is well known that parasites are often highly aggregated on their hosts such that relatively few individuals host the large majority of parasites. when the parasites are vectors of infectious disease, a key consequence of this aggregation can be increased disease transmission rates. the cause of this aggregation, however, is much less clear, especially for parasites such as arthropod vectors, which generally spend only a short time on their hosts. regression-based analyses of ticks on various ...201122216216
field studies on lyme disease in north america.the primary tick vector of borrelia burgdorferi in eastern and central north america is ixodes dammini; in western north america, ixodes pacificus. searching for the appropriate vector is the first step in determining whether a region is endemic and enzootic for the spirochete b burgdorferi, the etiological agent of lyme disease, followed by examination of the ticks (questing or already attached to hosts) and wildlife for the spirochete. questing ticks can be collected through a variety of metho ...199122529709
experimental infections of the reservoir species peromyscus leucopus with diverse strains of borrelia burgdorferi, a lyme disease agent.the rodent peromyscus leucopus is a major natural reservoir for the lyme disease agent borrelia burgdorferi and a host for its vector ixodes scapularis. at various locations in northeastern united states 10 to 15 b. burgdorferi strains coexist at different prevalences in tick populations. we asked whether representative strains of high or low prevalence differed in their infections of p. leucopus. after 5 weeks of experimental infection of groups with each of 6 isolates, distributions and burden ...201223221801
reservoir competence of wildlife host species for babesia microti.human babesiosis is an increasing health concern in the northeastern united states, where the causal agent, babesia microti, is spread through the bite of infected ixodes scapularis ticks. we sampled 10 mammal and 4 bird species within a vertebrate host community in southeastern new york to quantify reservoir competence (mean percentage of ticks infected by an individual host) using real-time pcr. we found reservoir competence levels >17% in white-footed mice (peromyscus leucopus), raccoons (pro ...201223171673
potential role of deer tick virus in powassan encephalitis cases in lyme disease-endemic areas of new york, u.s.a.powassan virus, a member of the tick-borne encephalitis group of flaviviruses, encompasses 2 lineages with separate enzootic cycles. the prototype lineage of powassan virus (powv) is principally maintained between ixodes cookei ticks and the groundhog (marmota momax) or striped skunk (mephitis mephitis), whereas the deer tick virus (dtv) lineage is believed to be maintained between ixodes scapularis ticks and the white-footed mouse (peromyscus leucopus). we report 14 cases of powassan encephalit ...201324274334
novel hepatozoon in vertebrates from the southern united states.abstract novel hepatozoon spp. sequences collected from previously unrecognized vertebrate hosts in north america were compared with documented hepatozoon 18s rrna sequences in an effort to examine phylogenetic relationships between the different hepatozoon organisms found cycling in nature. an approximately 500 base pair fragment of 18s rdna common to hepatozoon spp. and some other apicomplexans was amplified and sequenced from the tissues or blood of 16 vertebrate host species from the souther ...201121506825
complex life cycle of pterygodermatites peromysci, a trophically transmitted parasite of the white-footed mouse (peromyscus leucopus).the aim of this study is to experimentally verify the intermediate host of a common gastrointestinal nematode, pterygodermatites peromysci, infecting the white-footed mouse (peromyscus leucopus) and describe the complex life cycle. as with other nematodes in the family rictulariidae, adult worms reside in the small intestine of the host, and infective eggs are shed into the environment where they are ingested by scavenger insects. a field survey of common nocturnal insects on the forest floors o ...201121766236
variable infection dynamics in four peromyscus species following experimental inoculation with baylisascaris procyonis.wild rodents such as peromyscus spp. are intermediate hosts for the zoonotic ascarid baylisascaris procyonis (raccoon roundworm), and previous studies indicate peromyscus leucopus (white-footed mouse) likely serves an important role in parasite ecology. natural infections have been sporadically identified in a few peromyscus spp., but no data are available on differences in susceptibility among the many other species. we compared survival and infection dynamics of b. procyonis in 4 species ( p. ...201627351237
poleward expansion of the white-footed mouse (peromyscus leucopus) under climate change: implications for the spread of lyme disease.the white-footed mouse (peromyscus leucopus) is an important reservoir host for borrelia burgdorferi, the pathogen responsible for lyme disease, and its distribution is expanding northward. we used an ecological niche factor analysis to identify the climatic factors associated with the distribution shift of the white-footed mouse over the last 30 years at the northern edge of its range, and modeled its current and potential future (2050) distributions using the platform biomod. a mild and shorte ...201324260464
feeding of ticks on animals for transmission and xenodiagnosis in lyme disease research.transmission of the etiologic agent of lyme disease, borrelia burgdorferi, occurs by the attachment and blood feeding of ixodes species ticks on mammalian hosts. in nature, this zoonotic bacterial pathogen may use a variety of reservoir hosts, but the white-footed mouse (peromyscus leucopus) is the primary reservoir for larval and nymphal ticks in north america. humans are incidental hosts most frequently infected with b. burgdorferi by the bite of ticks in the nymphal stage. b. burgdorferi adap ...201324022694
emergence of ixodes scapularis and borrelia burgdorferi, the lyme disease vector and agent, in ohio.lyme disease, the most common vector-borne disease in the united states, is caused by a tick-borne infection with borrelia burgdorferi. currently, ohio is considered by the centers for disease control and prevention (cdc) to be non-endemic for lyme disease. the low incidence of lyme disease in this state was largely attributed to the absence of the transmitting vector, ixodes scapularis, commonly known as the blacklegged tick. however, a tick surveillance program established by ohio department o ...201424926441
climate change and habitat fragmentation drive the occurrence of borrelia burgdorferi, the agent of lyme disease, at the northeastern limit of its distribution.lyme borreliosis is rapidly emerging in canada, and climate change is likely a key driver of the northern spread of the disease in north america. we used field and modeling approaches to predict the risk of occurrence of borrelia burgdorferi, the bacteria causing lyme disease in north america. we combined climatic and landscape variables to model the current and future (2050) potential distribution of the black-legged tick and the white-footed mouse at the northeastern range limit of lyme diseas ...201425469157
lyme disease risk not amplified in a species-poor vertebrate community: similar borrelia burgdorferi tick infection prevalence and ospc genotype frequencies.the effect of biodiversity declines on human health is currently debated, but empirical assessments are lacking. lyme disease provides a model system to assess relationships between biodiversity and human disease because the etiologic agent, borrelia burgdorferi, is transmitted in the united states by the generalist black-legged tick (ixodes scapularis) among a wide range of mammalian and avian hosts. the 'dilution effect' hypothesis predicts that species-poor host communities dominated by white ...201424787999
geography, deer, and host biodiversity shape the pattern of lyme disease emergence in the thousand islands archipelago of ontario, canada.in the thousand islands region of eastern ontario, canada, lyme disease is emerging as a serious health risk. the factors that influence lyme disease risk, as measured by the number of blacklegged tick (ixodes scapularis) vectors infected with borrelia burgdorferi, are complex and vary across eastern north america. despite study sites in the thousand islands being in close geographic proximity, host communities differed and both the abundance of ticks and the prevalence of b. burgdorferi infecti ...201424416435
phylogeographic structure of the white-footed mouse and the deer mouse, two lyme disease reservoir hosts in québec.modification of a species range is one of many consequences of climate change and is driving the emergence of lyme disease in eastern canada. the primary reservoir host of the bacteria responsible for lyme disease, borrelia burgdorferi, is the white-footed mouse (peromyscus leucopus), whose range is rapidly shifting north into southern québec. the deer mouse, p. maniculatus, is occurring over most québec province and is a less competent host for b. burgdorferi. here, we compared the phylogeograp ...201526633555
disruption of bbe02 by insertion of a luciferase gene increases transformation efficiency of borrelia burgdorferi and allows live imaging in lyme disease susceptible c3h mice.lyme disease is the most prevalent tick-borne disease in north america and europe. the causative agent, borrelia burgdorferi persists in the white-footed mouse. infection with b. burgdorferi can cause acute to persistent multisystemic lyme disease in humans. some disease manifestations are also exhibited in the mouse model of lyme disease. genetic manipulation of b. burgdorferi remains difficult. first, b. burgdorferi contains a large number of endogenous plasmids with unique sequences encoding ...201526069970
association between body size and reservoir competence of mammals bearing borrelia burgdorferi at an endemic site in the northeastern united states.the reservoirs for the lyme disease agent, borrelia burgdorferi, are dominated by several different small to medium sized mammals in eastern north america.201526024881
broad diversity of host responses of the white-footed mouse peromyscus leucopus to borrelia infection and antigens.peromyscus leucopus, the white-footed mouse, is one of the more abundant mammals of north america and is a major reservoir host for at least five tickborne diseases of humans, including lyme disease and a newly-recognized form of relapsing fever. in comparison to mus musculus, which is not a natural reservoir for any of these infections, there has been little research on experimental infections in p. leucopus. with the aim of further characterizing the diversity of phenotypes of host responses, ...201526005106
the lyme disease pathogen has no effect on the survival of its rodent reservoir host.zoonotic pathogens that cause devastating morbidity and mortality in humans may be relatively harmless in their natural reservoir hosts. the tick-borne bacterium borrelia burgdorferi causes lyme disease in humans but few studies have investigated whether this pathogen reduces the fitness of its reservoir hosts under natural conditions. we analyzed four years of capture-mark-recapture (cmr) data on a population of white-footed mice, peromyscus leucopus, to test whether b. burgdorferi and its tick ...201525688863
the effect of spatial heterogenity on the aggregation of ticks on white-footed mice.parasites are often aggregated on a minority of the individuals in their host populations. although host characteristics are commonly presumed to explain parasite aggregation on hosts, spatio-temporal aggregation of parasites during their host-seeking stages may have a dominant effect on the aggregation on hosts. we aimed to quantify, using mixed models, repeatability and autocorrelation analyses, the degree to which the aggregation of blacklegged ticks (ixodes scapularis) on white-footed mice ( ...201222409977
an experimental test of competition among mice, chipmunks, and squirrels in deciduous forest fragments.mixed hardwood forests of the northeast united states support a guild of granivorous/omnivorous rodents including gray squirrels (sciurus carolinensis), eastern chipmunks (tamias striatus), and white-footed mice (peromyscus leucopus). these species coincide geographically, co-occur locally, and consume similar food resources. despite their idiosyncratic responses to landscape and patch variables, patch occupancy models suggest that competition may influence their respective distributions and abu ...201323824654
prevalence of human-active and variant 1 strains of the tick-borne pathogen anaplasma phagocytophilum in hosts and forests of eastern north america.anaplasmosis is an emerging infectious disease caused by infection with the bacterium anaplasma phagocytophilum. in the eastern united states, a. phagocytophilum is transmitted to hosts through the bite of the blacklegged tick, ixodes scapularis. we determined the realized reservoir competence of 14 species of common vertebrate hosts for ticks by establishing the probability that each species transmits two important strains of a. phagocytophilum (a. phagocytophilum human-active, which causes hum ...201424865688
cloning and molecular characterization of telomerase reverse transcriptase (tert) and telomere length analysis of peromyscus leucopus.telomerase reverse transcriptase (tert) is the catalytic subunit of telomerase complex that regulates telomerase activity to maintain telomere length for all animals with linear chromosomes. as the mus musculus (mm) laboratory mouse has very long telomeres compared to humans, a potential alternative animal model for telomere research is the peromyscus leucopus (pl) mouse that has telomere lengths close to the human range and has the wild counterparts for comparison. we report the full tert codin ...201525962353
faecal avoidance and selective foraging: do wild mice have the luxury to avoid faeces?host-parasite interactions are a key determinant of the population dynamics of wild animals, and behaviours that reduce parasite transmission and infection may be important for improving host fitness. while antiparasite behaviours have been demonstrated in laboratory animals and domesticated ungulates, whether these behaviours operate in the wild is poorly understood. therefore, examining antiparasite behaviours in natural populations is crucial for understanding their ecological significance. i ...024027342
concordance of bacterial communities of two tick species and blood of their shared rodent host.high-throughput sequencing is revealing that most macro-organisms house diverse microbial communities. of particular interest are disease vectors whose microbiome could potentially affect pathogen transmission and vector competence. we investigated bacterial community composition and diversity of the ticks dermacentor variabilis (n = 68) and ixodes scapularis (n = 15) and blood of their shared rodent host, peromyscus leucopus (n = 45) to quantify bacterial diversity and concordance. the 16s rrna ...201525847197
prevalence of anaplasma phagocytophilum and babesia microti in ixodes scapularis from a newly established lyme disease endemic area, the thousand islands region of ontario, canada.blacklegged ticks (ixodes scapularis) are vectors for several important human diseases, including lyme disease, human granulocytic anaplasmosis (hga), and human babesiosis, caused by borrelia burgdorferi, anaplasma phagocytophilum, and babesia microti, respectively. the continued northward range expansion of blacklegged ticks and associated pathogens is an increasing public health concern in canada. the thousand islands region of eastern ontario has recently been identified as a new endemic area ...201526393476
modeling the influence of peromyscus leucopus body mass, sex, and habitat on immature dermacentor variabilis burden.immature (larvae and nymph) tick burden on rodents is an important determinant of adult tick population size and understanding infectious disease dynamics. the objective of this research was to build a descriptive model for immature dermacentor variabilis burden on peromyscus leucopus. mice were live-trapped on two permanent grids in an old field and an early successional forest every other month between april and october, 2006-2009. negative binomial regression was used to examine the associati ...201223181857
detection of human pathogenic ehrlichia muris-like agent in peromyscus leucopus.an ehrlichia muris-like (eml) bacterium was recently detected in humans and ixodes scapularis ticks in minnesota and wisconsin. the reservoir for this agent is unknown. to investigate the occurrence of the eml agent, groel pcr testing and sequencing was performed on blood from small mammals and white-tailed deer that were collected in areas where human and tick infections were previously demonstrated. dna of the eml agent was detected in two peromyscus leucopus of 146 small mammals (1.4%); while ...201525481346
expansion of zoonotic babesiosis and reported human cases, connecticut, 2001-2010.to document the expansion of human babesiosis in connecticut, we analyzed reservoir host sera for seroreactivity to babesia microti franca and reviewed connecticut human surveillance case data collected during 2001-2010. sera from white-footed mice, peromyscus leucopus rafinesque, from 10 towns in 5 counties, collected at 4-7-yr periods between 2001 and 2010, were tested for total immunoglobulins. the prevalence of b. microti-positive mice was compared with confirmed and probable human case repo ...201424605475
detection of babesia microti and borrelia burgdorferi in host-seeking ixodes scapularis (acari: ixodidae) in monmouth county, new jersey.the etiological agents that cause human babesiosis (babesia microti) and lyme disease (borrelia burgdorferi) share a common tick vector (ixodes scapularis say) and rodent reservoir (peromyscus leucopus), but because the geographical distribution of babesiosis is more restricted than lyme disease, it was not considered a nationally notifiable disease until 2011. although recent studies have shown dramatic increases in the number of cases of babesiosis and expansion of its range, little is known a ...201323540127
baylisascaris procyonis infection in white-footed mice: predicting patterns of infection from landscape habitat attributes.there is a growing body of evidence that habitat fragmentation resulting from anthropogenic land use can alter the transmission dynamics of infectious disease. baylisascaris procyonis , a parasitic roundworm with the ability to cause fatal central nervous system disease in many mammals, including humans, is a zoonotic threat, and research suggests that parasite recruitment rates by intermediate hosts are highly variable among forest patches in fragmented landscapes. during 2008, we sampled 353 w ...201323656487
closely-related borrelia burgdorferi (sensu stricto) strains exhibit similar fitness in single infections and asymmetric competition in multiple infections.wild hosts are commonly co-infected with complex, genetically diverse, pathogen communities. competition is expected between genetically or ecologically similar pathogen strains which may influence patterns of coexistence. however, there is little data on how specific strains of these diverse pathogen species interact within the host and how this impacts pathogen persistence in nature. ticks are the most common disease vector in temperate regions with borrelia burgdorferi, the causative agent of ...201728166814
serum antibodies to borrelia burgdorferi, anaplasma phagocytophilum, and babesia microti in recaptured white-footed mice.a mark-release-recapture study was conducted during 2007 through 2010 in six, tick-infested sites in connecticut, united states to measure changes in antibody titers for borrelia burgdorferi sensu stricto, anaplasma phagocytophilum, and babesia microti in peromyscus leucopus (white-footed mice). there was an overall recapture rate of 40%, but only four tagged mice were caught in ≥2 yr. sera from 561 mice were analyzed for total antibodies to b. burgdorferi and a. phagocytophilum by using whole-c ...201323568904
identification of borrelia burgdorferi ospc genotypes in host tissue and feeding ticks by terminal restriction fragment length polymorphisms.we developed a high-throughput method based on terminal restriction fragment length polymorphisms (t-rflp) to identify ospc genotypes from field-collected samples of borrelia burgdorferi. we first validated the method by analyzing b. burgdorferi ospc previously identified by sequencing. we then analyzed and compared ospc genotypes detected from ear biopsy tissue from natural populations of the white-footed mouse, a major b. burgdorferi reservoir host species in the eastern united states, and lar ...201323183976
borrelia burgdorferi promotes the establishment of babesia microti in the northeastern united states.babesia microti and borrelia burgdorferi, the respective causative agents of human babesiosis and lyme disease, are maintained in their enzootic cycles by the blacklegged tick (ixodes scapularis) and use the white-footed mouse (peromyscus leucopus) as primary reservoir host. the geographic range of both pathogens has expanded in the united states, but the spread of babesiosis has lagged behind that of lyme disease. several studies have estimated the basic reproduction number (r0) for b. microti ...201425545393
peromyscus leucopus mice: a potential animal model for haematological studies.peromyscus leucopus mice share physical similarities with laboratory mice mus musculus (mm) but have higher agility and longer lifespan. we compared domesticated p. leucopus linville (pll) and m. musculus c57bl/6 (mmb6) mice for cellular composition of peripheral blood (pb), bone marrow (bm) and spleen. pll mice had significantly fewer platelets and significantly more monocytes in the blood, and notably fewer megakaryocytes in the bm. spleens of pll mice were significantly smaller, with 50% fewe ...201425116892
stable transmission of borrelia burgdorferi sensu stricto on the outer banks of north carolina.the spirochaete (borrelia burgdorferi) associated with lyme disease was detected in questing ticks and rodents during a period of 18 years, 1991-2009, at five locations on the outer banks of north carolina. the black-legged tick (ixodes scapularis) was collected at varied intervals between 1991 and 2009 and examined for b. burgdorferi. the white-footed mouse (peromyscus leucopus), house mouse (mus musculus) marsh rice rat (oryzomys palustris), marsh rabbit (sylvilagus palustris), eastern cottont ...201627966833
a method to distinguish morphologically similar peromyscus species using extracellular rna and high-resolution melt analysis.a method applying high-resolution melt (hrm) analysis to pcr products copied and amplified from extracellular rna (exrna) has been developed to distinguish two morphologically similar peromyscus species: peromyscus leucopus and peromyscus maniculatus. p. leucopus is considered the primary reservoir host of borrelia burgdorferi, the causative agent for lyme disease in north america. in northern minnesota the habitat ranges of p. leucopus overlaps with that of p. maniculatus. serum samples from li ...201627349513
[lyme disease: an update].lyme disease is an emerging infection caused by the spirochete borrelia burgdorferi. it is the most common vector-borne disease in the usa and europe, and it is transmitted to humans through the bite of ticks of the genus ixodes. its animal reservoirs are the white-tailed deer, the white-footed mouse, and other small mammals. it is considered the new "great imitator", with its diagnosis being a major challenge. traditionally it is divided into four stages, early localized disease, early dissemin ...201424481435
genetic structure of the white-footed mouse in the context of the emergence of lyme disease in southern québec.the white-footed mouse (peromyscus leucopus) has expanded its northern limit into southern québec over the last few decades. p. leucopus is a great disperser and colonizer and is of particular interest because it is considered a primary reservoir for the spirochete bacterium that causes lyme disease. there is no current information on the gene flow between mouse populations on the mountains and forest fragments found scattered throughout the montérégie region in southern québec, and whether vari ...201323919153
inferring epitopes of a polymorphic antigen amidst broadly cross-reactive antibodies using protein microarrays: a study of ospc proteins of borrelia burgdorferi.epitope mapping studies aim to identify the binding sites of antibody-antigen interactions to enhance the development of vaccines, diagnostics and immunotherapeutic compounds. however, mapping is a laborious process employing time- and resource-consuming 'wet bench' techniques or epitope prediction software that are still in their infancy. for polymorphic antigens, another challenge is characterizing cross-reactivity between epitopes, teasing out distinctions between broadly cross-reactive respo ...201323826301
predicted outcomes of vaccinating wildlife to reduce human risk of lyme disease.vaccination efforts for lyme disease prevention in humans have focused on wildlife reservoirs to target the causative agent, borrelia burgdorferi, for elimination in vector ticks. multiple host species are involved in the transmission and maintenance of the bacterium, but not all host species can be vaccinated effectively. to evaluate vaccinating a subset of hosts in the context of host-tick interactions, we constructed and evaluated a dynamic model of b. burgdorferi transmission in mice. our an ...201222251312
experimental evaluation of peromyscus leucopus as a reservoir host of the ehrlichia muris-like agent.the ehrlichia muris-like agent (emla) is a newly recognized human pathogen in the north central united states. although blacklegged ticks (ixodes scapularis) have been identified as capable vectors, wild reservoirs have not yet been established for emla. as key hosts for i. scapularis, white-footed mice (peromyscus leucopus) are important reservoirs for various tick-borne pathogens, and potentially, for emla. the objective of this study was to evaluate reservoir competence in p. leucopus using a ...201728129781
co-feeding transmission of the ehrlichia muris-like agent to mice (mus musculus).the ehrlichia muris-like agent (emla) is a newly recognized human pathogen found in wisconsin and minnesota. ecological investigations have implicated both the blacklegged tick, ixodes scapularis, and the white-footed mouse, peromyscus leucopus, as playing roles in the maintenance of emla in nature. the work presented here shows that i. scapularis is an efficient vector of emla in a laboratory mouse model, but that dermacentor variabilis, another frequent human biting tick found in emla endemic ...201626824725
modeling powassan virus infection in peromyscus leucopus, a natural host.the tick-borne flavivirus, powassan virus (powv) causes life-threatening encephalitis in humans in north america and europe. powv is transmitted by ixodid tick vectors that feed on small to medium-sized mammals, such as peromyscus leucopus mice, which may serve as either reservoir, bridge or amplification hosts. intraperitoneal and intracranial inoculation of 4-week old peromyscus leucopus mice with 103 pfu of powv did not result in overt clinical signs of disease. however, following intracrania ...201728141800
infection resistance and tolerance in peromyscus spp., natural reservoirs of microbes that are virulent for humans.the widely-distributed north american species peromyscus leucopus and p. maniculatus of cricetine rodents are, between them, important natural reservoirs for several zoonotic diseases of humans: lyme disease, human granulocytic anaplasmosis, babesiosis, erhlichiosis, hard tickborne relapsing fever, powassan virus encephalitis, hantavirus pulmonary syndrome, and plague. while these infections are frequently disabling and sometimes fatal for humans, the peromyscines display little pathology and ap ...201727381345
the prevalence of trypanosoma cruzi, the causal agent of chagas disease, in texas rodent populations.rodent species were assessed as potential hosts of trypanosoma cruzi, the etiologic agent of chagas disease, from five sites throughout texas in sylvan and disturbed habitats. a total of 592 rodents were captured, resulting in a wide taxonomic representation of 11 genera and 15 species. heart samples of 543 individuals were successfully analyzed by sybrgreen-based quantitative pcr (qpcr) targeting a 166 bp fragment of satellite dna of t. cruzi. eight rodents representing six species from six gen ...201728091763
effects of disturbance on small mammal community structure in the new jersey pinelands, usa.we compared small mammal community composition among undisturbed habitats and habitats disturbed by military operations on warren grove gunnery range (wgr) in the new jersey pinelands. wgr is one of the largest tracts of protected land within this globally rare ecosystem. disturbance in the form of fire, mowing, soil disruption and logging has had a large effect on small mammal occurrence and distribution. of the 14 small mammal species that occur in the pinelands, 9 live on wgr, including large ...201222405445
food chain transfer and potential renal toxicity of mercury to small mammals at a contaminated terrestrial field site.mercury concentrations were determined in surface soil and biota at a contaminated terrestrial field site and were used to calculate transfer coefficients of mercury through various compartments of the ecosystem based on trophic relationships. mercury concentrations in all compartments (soil, vegetation, invertebrates, and small mammals) were higher than mercury concentrations in corresponding samples at local reference sites. nonetheless, mercury concentrations in biota did not exceed concentra ...199324201735
transcriptome resources for the white-footed mouse (peromyscus leucopus): new genomic tools for investigating ecologically divergent urban and rural populations.genomic resources are important and attainable for examining evolutionary change in divergent natural populations of nonmodel species. we utilized two next-generation sequencing (ngs) platforms, 454 and solid 5500xl, to assemble low-coverage transcriptomes of the white-footed mouse (peromyscus leucopus), a widespread and abundant native rodent in eastern north america. we sequenced liver mrna transcripts from multiple individuals collected from urban populations in new york city and rural popula ...201524980186
chemical attraction of dermacentor variabilis ticks parasitic to peromyscus leucopus based on host body mass and sex.macroparasites are commonly aggregated on a small subset of a host population. previous explanations for this aggregation relate to differences in immunocompetence or the degree to which hosts encounter parasites. we propose active tick host choice through chemical attraction as a potential mechanism leading to aggregated tick burdens. we test this hypothesis using a y-maze olfactometer, comparing chemical attraction responses of larval and nymphal dermacentor variabilis ticks parasitic to the w ...201323543274
isolation of the lyme disease spirochete borrelia mayonii from naturally infected rodents in minnesota.borrelia mayonii is a newly described member of the borrelia burgdorferi sensu lato complex that is vectored by the black-legged tick (ixodes scapularis say) and a cause of lyme disease in minnesota and wisconsin. vertebrate reservoir hosts involved in the enzootic maintenance of b. mayonii have not yet been identified. here, we describe the first isolation of b. mayonii from naturally infected white-footed mice (peromyscus leucopus rafinesque) and an american red squirrel (tamiasciurus hudsonic ...201728444198
liver microbiome of peromyscus leucopus, a key reservoir host species for emerging infectious diseases in north america.microbiome studies generally focus on the gut microbiome, which is composed of a large proportion of commensal bacteria. here we propose a first analysis of the liver microbiome using next generation sequencing as a tool to detect potentially pathogenic strains. we used peromyscus leucopus, the main reservoir host species of lyme disease in eastern north america, as a model and sequenced v5-v6 regions of the 16s gene from 18 populations in southern quebec (canada). the lactobacillus genus was fo ...201728412525
acquisition of borrelia burgdorferi infection by larval ixodes scapularis (acari: ixodidae) associated with engorgement measures.measuring rates of acquisition of the lyme disease pathogen, borrelia burgdorferi sensu lato johnson, schmid, hyde, steigerwalt & brenner, by the larval stage of ixodes scapularis say is a useful tool for xenodiagnoses of b. burgdorferi in vertebrate hosts. in the nymphal and adult stages of i. scapularis, the duration of attachment to hosts has been shown to predict both body engorgement during blood feeding and the timing of infection with b. burgdorferi. however, these relationships have not ...201728399208
paracellular nutrient absorption is higher in bats than rodents: integrating from intact animals to the molecular level.flying vertebrates have been hypothesized to rely heavily on paracellular absorption of nutrients to compensate for having smaller intestines than non-flyers. we tested this hypothesis in an insectivorous bat (myotis lucifugus) and two insect-eating rodents (onychomys leucogaster and peromyscus leucopus). in intact animals, the fractional absorption of orally dosed l-arabinose (mr 150) was 82% in m. lucifugus, which was more than twice that of the rodents. absorption of creatinine (mr 113) was g ...201425063860
when is a parasite not a parasite? effects of larval tick burdens on white-footed mouse survival.many animal species can carry considerable burdens of ectoparasites: parasites living on the outside of a host's body. ectoparasite infestation can decrease host survival, but the magnitude and even direction of survival effects can vary depending on the type of ectoparasite and the nature and duration of the association. when ectoparasites also serve as vectors of pathogens, the effects of ectoparasite infestation on host survival have the potential to alter disease dynamics by regulating host ...201425000767
co-feeding transmission facilitates strain coexistence in borrelia burgdorferi, the lyme disease agent.coexistence of multiple tick-borne pathogens or strains is common in natural hosts and can be facilitated by resource partitioning of the host species, within-host localization, or by different transmission pathways. most vector-borne pathogens are transmitted horizontally via systemic host infection, but transmission may occur in the absence of systemic infection between two vectors feeding in close proximity, enabling pathogens to minimize competition and escape the host immune response. in a ...201628089780
proposal to reclassify ehrlichia muris as ehrlichia muris subsp. muris subsp. nov. and description of ehrlichia muris subsp. eauclairensis subsp. nov., a newly recognized tick-borne pathogen of humans.we have previously described a novel taxon of the genus ehrlichia (type strain wisconsint), closely related to ehrlichia muris, that causes human ehrlichiosis among patients with exposures to ticks in the upper midwestern usa. dna from this bacterium was also detected in ixodes scapularis and peromyscus leucopus collected in minnesota and wisconsin. to determine the relationship between the e. muris-like agent (emla) and other species of the genus ehrlichia phenotypic, genotypic and epidemiologi ...201728699575
interferon signaling in peromyscus leucopus confers a potent and specific restriction to vector-borne flaviviruses.tick-borne flaviviruses (tbfvs), including powassan virus and tick-borne encephalitis virus cause encephalitis or hemorrhagic fevers in humans with case-fatality rates ranging from 1-30%. despite severe disease in humans, tbfv infection of natural rodent hosts has little noticeable effect. currently, the basis for resistance to disease is not known. we hypothesize that the coevolution of flaviviruses with their respective hosts has shaped the evolution of potent antiviral factors that suppress v ...201728650973
relative preference and localized food affect predator space use and consumption of incidental prey.abundant, localized foods can concentrate predators and their foraging efforts, thus altering both the spatial distribution of predation risk and predator preferences for prey that are encountered incidentally. however, few investigations have quantified the spatial scale over which localized foods affect predator foraging behavior and consumption of incidental prey. in spring 2010, we experimentally tested how point-source foods altered how generalist predators (white-footed mice, peromyscus le ...201626978659
ticks, ixodes scapularis, feed repeatedly on white-footed mice despite strong inflammatory response: an expanding paradigm for understanding tick-host interactions.ticks transmit infectious agents including bacteria, viruses and protozoa. however, their transmission may be compromised by host resistance to repeated tick feeding. increasing host resistance to repeated tick bites is well known in laboratory animals, including intense inflammation at the bite sites. however, it is not known whether this also occurs in wild rodents such as white-footed mice, peromyscus leucopus, and other wildlife, or if it occurs at all. according to the "host immune incompet ...201729326693
signatures of selection in mammalian clock genes with coding trinucleotide repeats: implications for studying the genomics of high-pace adaptation.climate change is predicted to affect the reproductive ecology of wildlife; however, we have yet to understand if and how species can adapt to the rapid pace of change. clock genes are functional genes likely critical for adaptation to shifting seasonal conditions through shifts in timing cues. many of these genes contain coding trinucleotide repeats, which offer the potential for higher rates of change than single nucleotide polymorphisms (snps) at coding sites, and, thus, may translate to fast ...201728944015
insights on the host associations and geographic distribution of hymenolepis folkertsi (cestoda: hymenolepididae) among rodents across temperate latitudes of north america.synoptic data and an understanding of helminth parasite diversity among diverse rodent assemblages across temperate latitudes of north america remain remarkably incomplete. renewed attention to comprehensive survey and inventory to establish the structure of biodiverse faunas is essential in providing indicators and proxies for identifying the outcomes of accelerating change linked to climate warming and anthropogenic forcing. subsequent to the description of hymenolepis folkertsi in the oldfiel ...201627630100
hematopoietic aging biomarkers in peromyscus leucopus mice.we analyzed hematopoietic phenotypes in peromyscus leucopus (pl) mice at young (2-9 months), middle (22-23 months) and old (33-46 months) ages aimed at characterizing age-associated changes in this unique rodent species. we found a significantly higher number of monocytes in old pl mice in peripheral blood, and higher proportions of cd44+ cells in blood, spleen and bone marrow in old pl mice than in middle and young counterparts. we conclude that elevated blood monocyte counts and up-regulated h ...201728620625
inbreeding and selection shape genomic diversity in captive populations: implications for the conservation of endangered species.captive breeding programs are often initiated to prevent species extinction until reintroduction into the wild can occur. however, the evolution of captive populations via inbreeding, drift, and selection can impair fitness, compromising reintroduction programs. to better understand the evolutionary response of species bred in captivity, we used nearly 5500 single nucleotide polymorphisms (snps) in populations of white-footed mice (peromyscus leucopus) to measure the impact of breeding regimes o ...201728423000
peromyscus leucopus mouse brain transcriptome response to powassan virus infection.powassan virus (powv) is a tick-borne flavivirus responsible for life-threatening encephalitis in north america and some regions of russia. the ticks that have been reported to transmit the virus belong to the ixodes species, and they feed on small-to-medium-sized mammals, such as peromyscus leucopus mice, skunks, and woodchucks. we previously developed a p. leucopus mouse model of powv infection, and the model is characterized by a lack of clinical signs of disease following intraperitoneal or ...201729147886
predation hazard and seed removal by small mammals: microhabitat versus patch scale effects.predator avoidance may involve response strategies of prey species that are time and space specific. many studies have shown that foraging individuals avoid predators by altering microhabitat usage; alternatively, sites may be selected according to larger-scale features of the habitat mosaic. we measured seed removal by two small mammal species (peromyscus leucopus, and microtus pennsylvanicus) at 474 stations over an experimentally created landscape of 12 patches, and under conditions of relati ...199328314039
dose and dose rate extrapolation factors for malignant and non-malignant health endpoints after exposure to gamma and neutron radiation.murine experiments were conducted at the janus reactor in argonne national laboratory from 1970 to 1992 to study the effect of acute and protracted radiation dose from gamma rays and fission neutron whole body exposure. the present study reports the reanalysis of the janus data on 36,718 mice, of which 16,973 mice were irradiated with neutrons, 13,638 were irradiated with gamma rays, and 6107 were controls. mice were mostly mus musculus, but one experiment used peromyscus leucopus. for both type ...201728939964
anatomical variation of the tarsus in common inbred mouse strains.rodent models are used for a variety of orthopedic research applications; however, anatomy references include mostly artistic representations. advanced imaging techniques, including micro-computed tomography (microct), can provide more accurate representations of subtle anatomical characteristics. a recent microct atlas of laboratory mouse (mus musculus) anatomy depicts the central and tarsal bone iii (t3) as a single bone, differing from previous references. fusion of tarsal bones is generally ...201727731937
comparing radiation toxicities across species: an examination of radiation effects in mus musculus and peromyscus leucopus.life shortening and pathological complications in similarly irradiated cohorts of the laboratory mouse mus musculus and the white-footed mouse peromyscus leucopus were recorded in the course of the janus studies conducted at argonne national laboratory from 1970-1992. this study examines how lifespan, tumor and non-tumor disease incidence, and tumor multiplicity are differentially affected by gamma-rays and neutron radiation exposure in two different animal species.201323362954
reduced mitochondrial ros, enhanced antioxidant defense, and distinct age-related changes in oxidative damage in muscles of long-lived peromyscus leucopus.comparing biological processes in closely related species with divergent life spans is a powerful approach to study mechanisms of aging. the oxidative stress hypothesis of aging predicts that longer-lived species would have lower reactive oxygen species (ros) generation and/or an increased antioxidant capacity, resulting in reduced oxidative damage with age than in shorter-lived species. in this study, we measured ros generation in the young adult animals of the long-lived white-footed mouse, pe ...201323325454
development of an automated dispenser for the delivery of medicinal or vaccine-laden baits to raccoons (procyon lotor).medicinal baits are distributed to manage zoonotic diseases, including raccoon (procyon lotor) rabies, but efficient distribution strategies are needed for suburban environments. we developed an automated dispenser that transfers fishmeal polymer baits at user-specified intervals from a magazine to a receptacle fitted with a filter that exploits raccoon dexterity to limit consumption by nontarget species. we introduce the concept of automated dispensers and describe bait removal success rates fo ...201525647587
population genomics of the anthropocene: urbanization is negatively associated with genome-wide variation in white-footed mouse populations.urbanization results in pervasive habitat fragmentation and reduces standing genetic variation through bottlenecks and drift. loss of genomewide variation may ultimately reduce the evolutionary potential of animal populations experiencing rapidly changing conditions. in this study, we examined genomewide variation among 23 white-footed mouse (peromyscus leucopus) populations sampled along an urbanization gradient in the new york city metropolitan area. genomewide variation was estimated as a pro ...201627099621
response to cecropia cocoons of mus musculus and two species of peromyscus.in rural areas cocoons of overwintering hyalophora cecropia spum close to the ground are opened and the pupae eaten by small mammals, but in urban areas, where cecropia populations are much larger, the cocoons are almost never opened by mammals. peromyscus leucopus noveboracensis and p. maniculatus bairdii are abundant in rural areas, but are largely replaced by mus musculus in urban areas. in laboratory experiments p. l. noveboracensis invariably opened cecropia cocoons and ate the pupae. p. m. ...197228306859
peromyscus as a model system for understanding the regulation of maternal behavior.the genus peromyscus has been used as a model system for understanding maternal behavior because of the diversity of reproductive strategies within this genus. this review will describe the ecological factors that determine litter size and litter quality in polygynous species such as peromyscus leucopus and peromyscus maniculatus. we will also outline the physiological and social factors regulating maternal care in peromyscus californicus, a monogamous and biparental species. because biparental ...201727381343
a comparison of scent marking between a monogamous and promiscuous species of peromyscus: pair bonded males do not advertise to novel females.scent marking can provide behavioral and physiological information including territory ownership and mate advertisement. it is unknown how mating status and pair cohabitation influence marking by males from different social systems. we compared the highly territorial and monogamous california mouse (peromyscus californicus) to the less territorial and promiscuous white-footed mouse (p. leucopus). single and mated males of both species were assigned to one of the following arenas lined with filte ...201222393377
sexual imprinting and speciation between two peromyscus species.sexual isolation, a reproductive barrier, can prevent interbreeding between diverging populations or species. sexual isolation can have a clear genetic basis; however, it may also result from learned mate preferences that form via sexual imprinting. here, we demonstrate that two sympatric species of mice-the white-footed mouse (peromyscus leucopus) and its sister species, the cotton mouse (p. gossypinus)-hybridize only rarely in the wild despite co-occurrence in the same habitat and lack of any ...201729231989
ixodes scapularis (acari: ixodidae) reservoir host diversity and abundance impacts on dilution of borrelia burgdorferi (spirochaetales: spirochaetaceae) in residential and woodland habitats in connecticut, united states.the dilution effect in the zoonotic disease transmission cycle theorizes that an increased diversity of host species will alter transmission dynamics, result in a decrease in pathogen prevalence, and potentially lower human disease incidence. the interrelationship of borrelia burgdorferi (johnson, schmid, hyde, steigerwalt, and brenner) (spirochaetales: spirochaetaceae), the etiological agent of lyme disease (ld), and its primary vector, blacklegged ticks (ixodes scapularis say) (acari: ixodidae ...201829340657
parallelisms and contrasts in the diverse ecologies of the anaplasma phagocytophilum and borrelia burgdorferi complexes of bacteria in the far western united states.anaplasma phagocytophilum and borrelia burgdorferi are two tick-borne bacteria that cause disease in people and animals. for each of these bacteria, there is a complex of closely related genospecies and/or strains that are genetically distinct and have been shown through both observational and experimental studies to have different host tropisms. in this review we compare the known ecologies of these two bacterial complexes in the far western usa and find remarkable similarities, which will help ...201629056734
high diversity of rna viruses in rodents, ethiopia.we investigated synanthropic small mammals in the ethiopian highlands as potential reservoirs for human pathogens and found that 2 rodent species, the ethiopian white-footed mouse and awash multimammate mouse, are carriers of novel mobala virus strains. the white-footed mouse also carries a novel hantavirus, the second murinae-associated hantavirus found in africa.201223171649
heritable variation in reaction norms of metabolism and activity across temperatures in a wild-derived population of white-footed mice (peromyscus leucopus).heritable variation in metabolic traits is likely to affect fitness. in this study, white-footed mice from wild-derived photoresponsive [r, infertile in short day length (sd)] and non-photoresponsive (nr, fertile in sd) selection lines were maintained under short-day (sd 8light:16dark), sub-thermoneutral conditions (22 or 12 °c). mice had significantly higher levels of food intake and resting metabolic rates (rmr) at low temperature. rmr differed significantly between lines (greater in nr mice). ...201424549715
interspecific comparison of hantavirus prevalence in peromyscus populations from a fragmented agro-ecosystem in indiana, usa.comparatively little is known about hantavirus prevalence within rodent populations from the midwestern us, where two species of native mice, the prairie deer mouse ( peromyscus maniculatus bairdii) and the white-footed mouse ( peromyscus leucopus noveboracensis), are dominant members of rodent communities. we sampled both species in central indiana and tested individuals for presence of hantavirus antibodies to determine whether seroprevalence (percent of individuals with antibodies reactive to ...201828977768
congruent morphological and genetic differentiation as a signature of range expansion in a fragmented landscape.phenotypic differentiation is often interpreted as a result of local adaptation of individuals to their environment. here, we investigated the skull morphological differentiation in 11 populations of the white-footed mouse (peromyscus leucopus). these populations were sampled in an agricultural landscape in the montérégie region (québec, canada), at the northern edge of the distribution of the white-footed mouse. we found a strong pattern of phenotypic differentiation matching the genetic struct ...201324324868
admixture on the northern front: population genomics of range expansion in the white-footed mouse (peromyscus leucopus) and secondary contact with the deer mouse (peromyscus maniculatus).range expansion has genetic consequences expected to result in differentiated wave-front populations with low genetic variation and potentially introgression from a local species. the northern expansion of peromyscus leucopus in southern quebec provides an opportunity to test these predictions using population genomic tools. our results show evidence of recent and post-glacial expansion. genome-wide variation in p. leucopus indicates two post-glacial lineages are separated by the st. lawrence ri ...201728902189
evolution of peromyscus leucopus mice in response to a captive environment.many wildlife species are propagated in captivity as models for behavioral, physiological, and genetic research or to provide assurance populations to protect threatened species. however, very little is known about how animals evolve in the novel environment of captivity. the histories of most laboratory strains are poorly documented, and protected populations of wildlife species are usually too small and too short-term to allow robust statistical analysis. to document the evolutionary change in ...201323940813
photoperiodic regulation of cerebral blood flow in white-footed mice (peromyscus leucopus).individuals living outside the tropics need to adjust their behavioral and physiological repertoires throughout the year to adapt to the changing seasons. white-footed mice (peromyscus leucopus) reduce hippocampal volumes, hippocampal-dependent memory function, long-term potentiation, and alter neurogenesis in response to short (winter-like) day lengths (photoperiods). during winter, these mice putatively shunt energy away from the brain to maximize peripheral thermogenesis, immune function, and ...201827570829
a father effect explains sex-ratio bias.sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. the ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of x- and y-chromosome-bearing sperm (cbs) in ejaculates due to segregation of sex chromosomes at meiosis. this expectation has been recently refuted. here we used pe ...201728855362
control of breathing and ventilatory acclimatization to hypoxia in deer mice native to high altitudes.we compared the control of breathing and heart rate by hypoxia between high- and low-altitude populations of peromyscus mice, to help elucidate the physiological specializations that help high-altitude natives cope with o2 limitation.201728640969
benign neonatal deep hypothermia in rodents and its relations to hibernation.the neonates of many rodent species survive deep hypothermia (t b = 0-8 °c). in key respects, this hypothermia is more akin to hibernation than was thought during much of the twentieth century, indicating that studies of neonatal hypothermia may usefully supplement studies of hibernation in understanding evolved tissue adaptations to near-freezing t b. to clarify evolutionary diversity in neonatal survival of deep hypothermia, neonates of six species or strains were subjected to a standardized p ...201728349198
microsatellite markers reveal low frequency of natural hybridization between the white-footed mouse (peromyscus leucopus) and deer mouse (peromyscus maniculatus) in southern quebec, canada.in some parts of southern quebec, two closely related rodent species - the white-footed mouse (peromyscus leucopus) and the deer mouse (peromyscus maniculatus) - have recently come in contact because of climate-driven changes in the distribution of the former. both species share similar morphology, ecology, and life history traits, which suggests that natural hybridization may be possible. hybridization among these two species can have important implications on the ecological roles these rodents ...201728177836
associations between innate immune function and ectoparasites in wild rodent hosts.immune function is an important component of host fitness, and high investment in immunity should occur when the benefits outweigh the costs, such as when risk of parasitism is high. we sampled two rodent hosts, white-footed mice (peromyscus leucopus), and prairie voles (microtus ochrogaster), and their tick, flea, and mite ectoparasites. a bacterial killing assay was used to measure the host's innate immune function. we hypothesized that classes of hosts (species, sexes, or age classes) with ov ...201323417097
monogamous and promiscuous rodent species exhibit discrete variation in the size of the medial prefrontal cortex.limbic-associated cortical areas, such as the medial prefrontal and retrosplenial cortex (mpfc and rs, respectively), are involved in the processing of emotion, motivation, and various aspects of working memory and have been implicated in mating behavior. to determine whether the independent evolution of mating systems is associated with a convergence in cortical mechanisms, we compared the size of mpfc and rs between the monogamous prairie vole (microtus ochrogaster) and the promiscuous meadow ...201222759599
buffering and plasticity in vital rates of oldfield rodents.1. under the hypothesis of environmental buffering, populations are expected to minimize the variance of the most influential vital rates; however, this may not be a universal principle. species with a life span <1 year may be less likely to exhibit buffering because of temporal or seasonal variability in vital rate sensitivities. further, plasticity in vital rates may be adaptive for species in a variable environment with reliable cues. 2. we tested for environmental buffering and plasticity in ...201222375923
invasive exotic shrub modifies a classic animal-habitat relationship and alters patterns of vertebrate seed predation.recent evidence suggests that invasive exotic plants can provide novel habitats that alter animal behavior. however, it remains unclear whether classic animal-habitat associations that influence the spatial distribution of plant-animal interactions, such as small mammal use of downed woody debris, persist in invaded habitats. we removed an invasive exotic shrub (buckthorn, rhamnus cathartica) from 7 of 15 plots in wisconsin. in each plot, we deployed 200 tagged quercus rubra seeds in november 20 ...201727936498
modeling biotic and abiotic influences on population size in small mammals.most previous work in population ecology has modeled density-dependent effects in isolation. in this paper, we concurrently modeled the effect of density-dependent and density-independent factors on the rate of population change (r t ) in peromyscus leucopus (white-footed mouse), using a ricker equation expanded to include weather and seasonality. from 1973 to 1996, we live-trapped p. leucopus monthly in a 2-ha ohio woodlot. population peaks (july to august) varied from 27 to 181 individuals, wh ...199828308199
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