Individual dietary preferences can be shaped by early experiences in the natal environment and may even influence where an animal settles as an adult. Examining animals' diets can also shed light on how they coexist with competitors. Here we use metabarcoding of faecal samples to investigate the influence of habitat type on diet composition in co-occurring brush mice, Peromyscus boylii, and pinyon mice, Peromyscus truei. Diet composition differed between habitat types for brush mice and differed between brush mice and pinyon mice within chaparral habitat. The results of this study support previous findings of dietary niche partitioning between Peromyscus species. Our results also reveal a potential mechanism of habitat selection, suggesting food preference as a possible driver of natal habitat preference induction. (c) 2026 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Space use by animals is affected by multiple factors; previous researchers have examined the effects of influences, such as sex, body condition, and population density on home range area. However, evaluating the simultaneous influences of multiple factors on animal space use has been relatively intractable due to sample size limitations. We capitalize on National Ecological Observatory Network (NEON) data to ask what factors determine space use by deer mice (genus Peromyscus). We examined data from 10 years of repeated captures of individually-identified mice at 36 sites across North America. We confirmed previous findings that males have larger home ranges than females and that home range area decreases with increasing animal density. In addition, our large sample size (N = 2,420 individuals) enabled us to examine the interacting influences of these, and other, phenotypic and extrinsic factors using a robust statistical framework. We found that the relationship between body condition and home range area differs between male and female mice, and that habitat type, latitude, and animal density all interact to influence space use. We conclude that data from large ecological networks can be used to examine important behavioral questions that have long eluded investigators.

Synchronized reproduction in animals is often associated with variation in interactions among individuals during particular stages of reproduction. Bats have been a model system for the study of these topics, with many documented reports of increased number or strength of social bonds among female bats during pregnancy and lactation. We investigated temporal variation in social network dynamics in relation to reproduction in the pallid bat (Antrozous pallidus), using intra-roost encounter data collected at fine spatial and temporal scales to construct temporally-aggregated social networks during pregnancy, lactation, weaning, and post-weaning. In contrast to the results of previous studies, we found that although the number of associations was higher than expected during lactation, association strength did not deviate from expectations based on networks constructed using data stream randomization. Further, we unexpectedly detected increased values for eigenvector centrality during phases after the completion of lactation, suggesting that well-connected individuals tended to associate after pups were weaned. Our results highlight the importance of fine-scale intra-roost dynamics and of interactions among individuals after the gestation and lactation phases of reproduction. Many bat species are found in large aggregations during reproduction; such grouping is likely a response to the energetic demands of pregnancy and lactation for female bats. Interactions among individual bats in such aggregations can be studied using social network analysis. We investigated temporal patterns in social network dynamics in roosting female pallid bats, using fine-scale interaction data collected within a large roost. We found that network dynamics varied across the reproductive season: during lactation, the number of associates of female pallid bats was much higher than expected. However, in contrast to previous studies, the strength of associations did not vary through time. Unexpectedly, we found that “well-connected” individuals tended to be connected to each other after young were weaned. Our results highlight the importance of using fine-scale interaction data within large bat roosts, and of documenting social interactions beyond pregnancy and lactation.

With ongoing anthropogenic climate change, there is increasing interest in how organisms are affected by higher temperatures, including how animals respond behaviorally to increasing temperatures. Movement behavior is especially relevant, as the ability of a species to shift its range is implicitly dependent upon movement capacity and motivation. Temperature may influence movement behavior of ectotherms both directly, through an increase in body temperature, and indirectly, through temperature-dependent effects on physiological and morphological traits. We investigated the influence of ambient temperature during two life stages, larval and adult, on body size and movement behavior of the painted lady butterfly (Vanessa cardui). We reared painted ladies to emergence at either a “low” (24 °C) or “high” (28 °C) temperature. At eclosion, we assessed flight behavior in an arena test. We used a full factorial experimental design in which half of the adults that emerged from each rearing treatment were tested at either the “low” or “high” temperature. We measured adult body size, including wingspan, and determined flight speed, distance, and duration from video recordings. Adult butterflies that experienced the higher temperature during development were larger. We documented an interaction of rearing x testing temperature on flight behavior: unexpectedly, the fastest butterflies were those who experienced a change in temperature, whether an increase or decrease, between rearing and testing. Individuals that experienced matching thermal environments flew more slowly, but for more time and covering more distance. We found no influence of body size per se on flight. We conclude that the potential role of “matching” thermal environments across life stages has been underinvestigated with regard to how organisms may respond to warming conditions.

This chapter provides an overview of dispersal in odonates and discusses how their biology makes them a potential model system for studying the dispersal process as well as its ecological and evolutionary consequences. It begins by briefly discussing the methods for studying dispersal in odonates and then it presents an overview of how dispersal shapes odonate population biology and species’ distributions. It goes on to discuss how various areas of anthropogenic change affect dispersal and colonization, and the associated implications for odonate conservation. Finally, the chapter closes with a discussion of promising new research directions in the study of odonate dispersal.

Synopsis Human activities are rapidly changing ecosystems around the world. These changes have widespread implications for the preservation of biodiversity, agricultural productivity, prevalence of zoonotic diseases, and sociopolitical conflict. To understand and improve the predictive capacity for these and other biological phenomena, some scientists are now relying on observatory networks, which are often composed of systems of sensors, teams of field researchers, and databases of abiotic and biotic measurements across multiple temporal and spatial scales. One well-known example is NEON, the US-based National Ecological Observatory Network. Although NEON and similar networks have informed studies of population, community, and ecosystem ecology for years, they have been minimally used by organismal biologists. NEON provides organismal biologists, in particular those interested in NEON's focal taxa, with an unprecedented opportunity to study phenomena such as range expansions, disease epidemics, invasive species colonization, macrophysiology, and other biological processes that fundamentally involve organismal variation. Here, we use NEON as an exemplar of the promise of observatory networks for understanding the causes and consequences of morphological, behavioral, molecular, and physiological variation among individual organisms.

Species are responding to global climate change in varied and nuanced ways. However, how species‐specific responses to climate change= affect interactions among species remains poorly understood. It is important to understand species interactions under potential climate change scenarios because those interactions can in turn alter community dynamics. In this study, we conducted two complementary experiments to examine how simulated warming might alter larval intraguild predation (IGP) rates and resulting adult assemblage composition in three species of North American dragonflies: Pachydiplax longipennis, Plathemis lydia and Libellula luctuosa. First, using both P. longipennis and L. luctuosa, we isolated interspecific and intraspecific pairs of larval dragonflies of different size differentials to determine how the size and species identity might influence IGP rates. In tandem, we conducted a year‐long mesocosm experiment with all three species to assess how simulated warming and heat waves influenced the resulting adult dragonfly assemblages. IGP trials revealed that P. longipennis individuals were much more likely to engage in IGP than L. luctuosa, regardless of size differential. In the mesocosm experiment, emerging adult assemblages were dominated by P. longipennis individuals, a pattern that was most pronounced in the control treatment. Our results indicate that while P. longipennis may be the competitively dominant species under current ambient conditions, warming may alter this dynamic and lessen the dominance of this species on the resulting assemblage composition.

Abstract Urban development can fragment and degrade remnant habitat. Such habitat alterations can have profound impacts on wildlife, including effects on population density, parasite infection status, parasite prevalence, and body condition. We investigated the influence of urbanization on populations of Merriam's kangaroo rat (Dipodomys merriami) and their parasites. We predicted that urban development would lead to reduced abundance, increased parasite prevalence in urban populations, increased probability of parasite infection for individual animals, and decreased body condition of kangaroo rats in urban versus wildland areas. We live trapped kangaroo rats at 5 urban and 5 wildland sites in and around Las Cruces, NM, USA from 2013 to 2015, collected fecal samples from 209 kangaroo rats, and detected endoparasites using fecal flotation and molecular barcoding. Seven parasite species were detected, although only two parasitic worms, Mastophorus dipodomis and Pterygodermatites dipodomis, occurred frequently enough to allow for statistical analysis. We found no effects of urbanization on population density or probability of parasite infection. However, wildland animals infected with P. dipodomis had lower body condition scores than infected animals in urban areas or uninfected animals in either habitat. Our results suggest that urban environments may buffer Merriam's kangaroo rats from the detrimental impacts to body condition that P. dipodomis infections can cause.

Urbanization fragments landscapes and can impede the movement of organisms through their environment, which can decrease population connectivity. Reduction in connectivity influences gene flow and allele frequencies, and can lead to a reduction in genetic diversity and the fixation of certain alleles, with potential negative effects for populations. Previous studies have detected effects of urbanization on genetic diversity and structure in terrestrial animals living in landscapes that vary in their degree of urbanization, even over very short distances. We investigated the effects of low-intensity urbanization on genetic diversity and genetic structure in Song Sparrows (Melospiza melodia). We captured 208 Song Sparrows at seven sites along a gradient of urbanization in and around Blacksburg, VA, USA, then genotyped them using a panel of fifteen polymorphic microsatellite loci. We found that genetic diversity was comparable among the seven study sites, and there was no evidence of genetic structuring among sites. These findings suggest that over a gradient of urbanization characterized by low density urban development, Song Sparrows likely exist in a single panmictic population.

Urban development can fragment and degrade habitat, and such habitat alterations can have profound effects on wildlife, including influencing population genetics. We used nine microsatellite loci to determine the effects of urbanization on genetic diversity and genetic structure in a native small mammal, Merriam's kangaroo rat, in areas in and around Las Cruces, NM, an expanding low density urban center. We found that Merriam's kangaroo rats in urban areas had increased genetic differentiation among populations as compared to wildland animals, and detected some evidence of lower genetic diversity in urban areas, indicating that the population genetics of a common and abundant wildlife species can be impacted by low density urbanization. Our results suggest that although abundant and common wildlife such as Merriam's kangaroo rats may persist in urban environments, these animals may still be influenced by more subtle effects of urbanization, such as genetic isolation.

For organisms with complex life cycles, climate change can have both direct effects and indirect effects that are mediated through plastic responses to temperature and that carry over beyond the developmental environment. We examined multiple responses to environmental warming in a dragonfly, a species whose life history bridges aquatic and terrestrial environments. We tested larval survival under warming and whether warmer conditions can create carry-over effects between life history stages. Rearing dragonfly larvae in an experimental warming array to simulate increases in temperature, we contrasted the effects of the current thermal environment with temperatures +2.5°C and +5°C above ambient, temperatures predicted for 50 and 100 years in the future for the study region. Aquatic mesocosms were stocked with dragonfly larvae (Erythemis collocata) and we followed survival of larvae to adult emergence. We also measured the effects of warming on the timing of the life history transition to the adult stage, body size of adults, and the relative size of their wings, an aspect of morphology key to flight performance. There was a trend toward reduced larval survival with increasing temperature. Warming strongly affected the phenology of adult emergence, advancing emergence by up to a month compared with ambient conditions. Additionally, our warmest conditions increased variation in the timing of adult emergence compared with cooler conditions. The increased variation with warming arose from an extended emergence season with fewer individuals emerging at any one time. Altered emergence patterns such as we observed are likely to place individuals emerging outside the typical season at greater risk from early and late season storms and will reduce effective population sizes during the breeding season. Contrary to expectations for ectotherms, body size was unaffected by warming. However, morphology was affected: at +5°C, dragonflies emerging from mesocosms had relatively smaller wings. This provides some of the first evidence that the effects of climate change on animals during their growth can have carry-over effects in morphology that will affect performance of later life history stages. In dragonflies, relatively smaller wings are associated with reduced flight performance, creating a link between larval thermal conditions and adult dispersal capacity.

Introduction: Hantaviruses are a group of globally distributed rodent-associated viruses, some of which are responsible for human morbidity and mortality. Sin Nombre orthohantavirus, a particularly virulent species of hantavirus associated with Peromyscus spp. mice, is actively monitored by the Department of Public Health in California (CDPH). Recently, CDPH documented high (40%) seroprevalence in a potentially novel reservoir species, the cactus mouse (Peromyscus eremicus) in Death Valley National Park. Methods: This study was performed in the extremely isolated Mojave Desert Amargosa River valley region of southeastern Inyo County, California, 105 km from Death Valley, approximately over the same time interval as the CDPH work in Death Valley (between 2011 and 2016). Similar rodent species were captured as in Death Valley and were tested for select hantaviruses using serology and RT-PCR to assess risk to human health and the conservation of the endemic endangered Amargosa vole. Results: Among 192 rodents tested, including 56 Peromyscus spp., only one seropositive harvest mouse (Reithrodontomys megalotis) was detected. Discussion: These data highlight the heterogeneity in the prevalence of hantavirus infection even among nearby desert communities and suggest that further studies of hantavirus persistence in desert environments are needed to more accurately inform the risks to public health and wildlife conservation.

Adults sometimes disperse, while philopatric offspring inherit the natal site, a pattern known as bequeathal. Despite a decades-old empirical literature, little theoretical work has explored when natural selection may favor bequeathal. We present a simple mathematical model of the evolution of bequeathal in a stable environment, under both global and local dispersal. We find that natural selection favors bequeathal when adults are competitively advantaged over juveniles, baseline mortality is high, the environment is unsaturated, and when juveniles experience high dispersal mortality. However, frequently bequeathal may not evolve, because the fitness cost for the adult is too large relative to inclusive fitness benefits. Additionally, there are many situations for which bequeathal is an ESS, yet cannot invade the population. As bequeathal in real populations appears to be facultative, yet-to-be-modeled factors like timing of birth in the breeding season may strongly influence the patterns seen in natural populations.