Journal of Animal Ecology最新文献

Temperature is a key ecological factor influencing biological processes across various levels of biological organization. At the individual level, temperature changes often impact life-history traits. The Temperature-Size Rule predicts lower body mass at higher temperatures, whereas the Metabolic Theory of Ecology predicts faster growth rates and shorter development times with rising temperature via its effects on metabolism. Butterflies, a highly diverse group distributed worldwide, often exhibit plastic responses to differences in ambient temperature. As such, climate change may potentially impact their life history traits, population dynamics and interactions. We conducted a Bayesian multilevel meta-regression of 71 studies published between 1960 and 2024, encompassing 673 effect sizes, to assess the impact of temperature variation on butterfly growth rate, development time and body mass across ontogenetic stages and sexes. Our meta-analysis reveals that rising temperatures markedly accelerate growth and shorten development time in butterflies at a rate of ca. 10%/Δ°C, while body mass is comparatively only weakly affected. These temperature effects on growth and development are consistent across sexes and life stages and are largely independent of evolutionary history, suggesting a basis in fundamental biochemical constraints. These patterns highlight the potential for climate change to reshape butterfly life cycles, population dynamics and ecological interactions.

Research Highlight: Monitoring the restoration process can help us understand the relationships between plants and animals. By manipulating the habitat, researchers can evaluate how changes in plant community influence the diversity and distribution of associated fauna. Yet, the mechanisms shaping pollinators' diversity in response to forest attributes remain poorly understood. The study by Xie et al. (2025) demonstrates how tree richness and forest canopy cover influence pollinator communities by mediating floral resource availability in the understory and modifying microclimatic conditions within the forest. The authors found that tree richness increases canopy cover and consequently changes the microclimatic conditions within the forest, which, in turn, reshapes the niche space available for bee communities. Such findings are fundamental because they reveal how changes in one component of biodiversity cascade into others. Such mechanistic insights are also crucial for scaling up biodiversity assessments using remote sensing and for guiding restoration strategies that move beyond vegetation recovery to the restoration of ecosystem functions.

Understanding the drivers of seasonal disease outbreaks remains a fundamental challenge in disease ecology. Periodic outbreaks can be driven by several seasonally varying factors, including pulses of susceptible individuals through births, changes in host behaviour and social aggregation and variation in host immunity. However, when these potential drivers overlap temporally, isolating their relative contributions to outbreak patterns becomes challenging. We studied Hendra virus, a zoonotic pathogen with seasonal spillovers from bats to horses and humans. Multiple seasonal factors have been hypothesized to drive Hendra virus transmission, including food shortages, birth pulses and changes in host aggregation, but their temporal overlap has made identifying primary drivers difficult. We conducted a 4-year longitudinal study of Pteropus bats to test whether seasonal birth pulses and the resulting influx of susceptible juveniles drive Hendra virus transmission. Using a Bayesian ageing model, we aged sexually immature bats and placed them into birth cohorts. We used our age predictions to model how viral shedding and antibody responses changed as bats aged. We tracked Bartonella spp. Infection-a bacterial pathogen requiring close contact for transmission-as an indicator of transmission opportunities within each cohort for comparison. We found no evidence that seasonal birth pulses of immunologically naïve juveniles drove Hendra virus transmission. Two out of three cohorts showed substantially reduced maternal antibody transfer compared to the 2018 cohort, with seroprevalence near zero at our earliest sampling timepoints and showed no clear evidence of synchronized seroconversion. Furthermore, Bartonella infection rates were consistent across cohorts, indicating that opportunities for pathogen transmission remained consistent across cohorts despite varying viral shedding patterns. Our findings demonstrate that birth pulses alone cannot explain observed patterns of Hendra virus outbreaks. These results highlight the importance of using multiple lines of evidence to evaluate competing mechanisms underlying seasonal disease dynamics, particularly when potential drivers coincide temporally.

Savanna ecosystems support unique biodiversity and provide livelihoods for millions of people. Yet, wild herbivores are in decline due to poaching and land-use change while livestock numbers are increasing. These changes in density and composition alter savanna vegetation. There are likely indirect cascading effects of altered vegetation on savanna arthropods, but our understanding is limited despite their pivotal role in ecosystem functioning. We evaluate how differences in mammalian herbivory affect terrestrial arthropods in a semiarid Kenyan savanna. We sampled ground-active arthropods (focusing on ants) in six herbivory treatments ranging from high-intensity herbivory to complete exclusion of large herbivores. Ant abundance and richness were not affected by herbivory treatments, but the community composition of ants and arthropods differed at extremely high and low levels of herbivory due to indirect impacts on vegetation. Community composition changes occurred under extremely high levels of herbivory because the resulting short-grass communities and patches of bare ground led to high species turnover in ants. By contrast, extremely low herbivory promoted woody encroachment that led to the loss of savanna specialists via both species turnover and nestedness. We conclude that cascading effects of mammalian herbivory play only a relatively small role in shaping savanna arthropod communities, except at extreme levels of herbivory. However, the occurrence of savannas with these extreme levels of herbivory, both high and low, is likely to increase in the future, which may lead to more widespread changes in ecosystem functioning as a consequence of shifts in arthropod community composition.

Environmental variability shapes species' population dynamics. Yet, the mechanisms linking environmental changes to individual-level metrics (e.g. foraging behaviour, body condition) and reproductive outcomes in the wild remain poorly understood. Energetics play a central role in mediating trade-offs between self-maintenance and reproduction under fluctuating environmental conditions. As such, it provides a powerful framework for identifying how individual responses to environmental variation scale up to influence population dynamics. Using a unique long-term monitoring and bio-logging dataset spanning over 25 years providing continuous measures of diving behaviour, feeding activity and daily energy expenditure, this study investigates how individual responses to environmental variation affect population dynamics. Focusing on Adélie penguins (Pygoscelis adeliae) during the energetically demanding chick-rearing phase, we integrated individual-level foraging and energetics data with colony-wide reproductive metrics to elucidate how environmental cues lead to life-history trade-offs. Winter sea-ice conditions exhibited a quadratic relationship with key individual behavioural and energetic parameters. Specifically, increased sea-ice concentration and delayed ice retreat led to longer foraging trips, reduced time spent diving and poorer body condition. At the population level, while energy expenditure was not associated with changes in reproductive outcome, increased foraging effort (time spent feeding per day) led to enhanced fledging success. Adverse on-land conditions, such as higher snowfall, had negative impacts on reproductive outcomes. These findings support the central role of energy as a common currency of maintenance and reproduction. By linking individual energetics to demographic performance, our work advances our understanding of how energy allocation strategies in response to environmental stressors shape population dynamics. These insights are crucial for improving predictive models of population trajectories and offer valuable guidance for conservation strategies aimed at mitigating the impacts of global change on ecosystems.

The influence of parasite infection on host thermal tolerance remains poorly understood. To address this, we investigated how infection with the trematode Himasthla elongata affects survival and heat shock protein expression in the blue mussel Mytilus edulis following repeated exposure to heat stress in a simulated intertidal environment. Two groups of mussels with experimentally induced low (55.3 $\pm$ 35.6 metacercariae per mussel) and high (148.6 $\pm$ 78.2 metacercariae per mussel) infection levels were exposed to air (31°C, 33°C or 35°C) for 2 h over 10 days to simulate a tidal cycle. Survival was assessed daily. In addition, the mRNA expression level of three heat shock genes (hsp24, hsp70 and hsp90) was assessed in mussels exposed to 17°C and 33°C for 2 h over a three-day period. Dissection confirmed clear differences in infection levels between groups. Survival decreased significantly with increasing air temperature, but in the 35°C treatment, mussels with high infection levels exhibited a near-significant increase in survival. Expression of hsp24, hsp70 and hsp90 increased with rising air temperatures, and high infection levels significantly upregulated hsp90. Although trematode infection did not significantly increase survival, our results suggest that trematode infection can protect against thermal stress by upregulating specific heat shock proteins in M. edulis. The hsp responses point to a parasite-induced tolerance mechanism, potentially through stress priming or frontloading, and highlight an overlooked role of parasitism in mediating thermal resilience in intertidal ecosystems.

Research Highlight: Journal of Animal Ecology, 00, 1-13. https://doi.org/10.1111/1365-2656.70182. Beyond rising temperatures, several parts of Africa are affected by aridification (more frequent and worsening droughts, lengthening dry seasons). Such drier conditions are likely to affect in several ways not only the many large herbivore species but also the rich carnivore guild that characterise African savannas, with consequences on the behavioural ecology of predator-prey interactions. Using data sets of exceptional quality on the feeding behaviour and the reproduction of leopards and lions covering 4 years of contrasting environmental conditions in a semi-arid African savanna, Balme et al. analysed the effect of drought conditions on the carnivores' diet composition, kill rates, prey biomass acquisition but also cub production and survival. They showed that droughts led to a higher prey biomass consumption for the two carnivore species although the underlying mechanisms differed (higher kill rate for leopards and larger consumed prey for lionesses). Additionally, they revealed that the probability of cub survival was driven by factors other than drought-driven food acquisition (such as intraguild predation by hyaenas for leopards and sarcoptic mange for lions). Balme et al. (2025) convincingly showed that droughts influence not only predator-prey interactions through several pathways, but also carnivore intraguild interactions. Altogether, their findings illustrate the difficulty to predict the impact of drier conditions on carnivore populations if we do not better unravel the mechanisms through which climate change affects both predator-prey and predator-predator interactions. Overall, this inspiring study invites us to conceptualise a larger framework to study interspecific interactions in African mammals in a context of a drier (and hotter) climate.

As a result of human-induced environmental change, animals increasingly face challenges that differ from those encountered throughout their evolutionary history. While this has caused dramatic declines for many species, some can persist by gathering information to reduce uncertainty, thereby minimising risks and exploiting new opportunities. The strategic use of social information can be particularly useful in enabling such uncertainty reduction. Here, we argue that the behavioural and affective states of others provide vital social information for animals to guide evaluations of risks and opportunities. Specifically, attending and responding to indicators of others' affective states through processes such as emotional contagion may facilitate information transmission. For instance, when exposed to a novel, ambiguous anthropogenic stimulus that could indicate either an opportunity or a threat, animals may use social information about others' affective states to decide whether to approach or avoid the stimulus. To increase immediate and long-term benefits, individuals might also alter their social behaviour and information use flexibly based on critical early-life experiences, the socio-ecological context or the behaviour and states of associates in the social network. Finally, given that an individual's affective state can influence how it copes with changing environments and makes appropriate decisions, we argue that there is a need for greater synergy between animal welfare and conservation efforts. Bridging the gap between ensuring individual-level welfare and population-level resilience will be crucial for ethical policies to protect wild animals responsibly in the face of human-induced rapid environmental change.

Natural history museums are invaluable resources for large-scale ecological and evolutionary studies, but certain ecological traits can be challenging to recover, particularly from fluid-preserved specimens. Stable isotope analysis is an elegant method for reconstructing the dietary niche over integrated timescales, and recovering this information from museum specimens can provide a critical axis of ecological information for studies of population dynamics through time and space. However, isotope ratios of tissues are known to be altered by extended contact with formalin and ethanol. Here, we assess whether intra- and interspecific variation in isotopic signature, which represent critical data used to assess metrics of niche diversity, can be reliably recovered following fluid preservation. We use a broad taxonomic distribution of squamates to compare niche metrics prior to and 8 weeks following a standard museum preservation process We could not recover intraindividual metrics of niche diversity but found that between-individual variation was not significantly altered, allowing for the reconstruction of community niche characteristics We present an example isotopic analysis from museum specimens representing generalist and specialist Thamnophis garter snake populations that aligns with empirical estimates of niche width We also present several additional analyses on tissue-specific effects, delipification and buffer storage, with useful insights for field collection and downstream analysis decisions.

The timing of breeding is an important aspect of any species' realised niche, reflecting adaptations to synchronise with food supplies, dilute predation, avoid competition and exploit seasonal fluctuations in resources. Breeding phenology is typically studied either through long-term monitoring of focal populations (limiting the strength of inferences about species-wide traits and trends) or, when conducted at a landscape level, using remotely visible traits (restricting most studies to plants). For the first time, this study demonstrates landscape-scale measurement of vertebrate breeding phenology using a network of 77 time-lapse cameras to monitor three sympatric penguin species across 37 colonies in the Antarctic Peninsula and Sub-Antarctic islands. Camera temperature loggers showed penguin colony locations are warming up four times faster (0.3°C/year) than the continental average (0.07°C/year), already the second fastest-warming area in the world. We analysed the start of the breeding season of Adélie, Chinstrap and Gentoo penguins at a sub-continental scale between 2012 and 2022. The phenology of all three species advanced at record rates (10.2 ± 2, 10.4 ± 1.5 and 13 ± 4 days/decade, respectively). Different demographic trends as well as intra- and inter-species differences in response to environmental change suggest niche-based response differences between species. Phenological advances are causing niche separation to reduce. In this context, the Gentoo penguins' generalist and resident nature seems better suited to compete for space and resources than krill-specialist Chinstraps and ice-specialist Adélies. Synthesis: A decade of observation of the three pygoscelid penguins shows they are advancing their settlement phenology at record speeds in relation to climate change across the Antarctic Peninsula. These changes are species-dependent, reflecting different vulnerabilities and opportunities depending on their niche and life-history traits. In the long term, the trend towards earlier settlement risks increasing inter-species competition, causing trophic and temporal mismatch, and reshaping community assemblages.