The Journal Of Animal Ecology[JOURNAL]
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200 papers
Maternal glucocorticoids have persistent effects on offspring social phenotype irrespective of opportunity for social buffering.
MacLeod KJ, Bouffet-Halle A, Wapstra E … +2 more , Uller T, While GM
J Anim Ecol · 2025 Sep · PMID 40954528 · Publisher ↗
Exposure to stressors and associated hormones during development can significantly affect offspring phenotype, including social and philopatric behaviour, but these effects can be mediated by the postnatal social environ...
Exposure to stressors and associated hormones during development can significantly affect offspring phenotype, including social and philopatric behaviour, but these effects can be mediated by the postnatal social environment ('social buffering'). While the effects of social buffering are well established for complex social behaviours-such as parental provisioning, grooming or cooperative care-the role of social buffering for simpler social interactions-such as parental tolerance of offspring-remains less understood. Here we used the facultatively social viviparous lizard, Liopholis whitii, to test the following: (i) the effects of elevated maternal glucocorticoid levels during gestation on offspring mass, growth, dispersal and social interactions after birth; and (ii) whether these effects are mediated by postnatal mother-offspring association. We conducted a factorial experiment in which pregnant lizards were given thrice-weekly doses of a glucocorticoid hormone (corticosterone) or a control during gestation. Their offspring were then raised either alone or with their mother for 3 weeks. We subsequently released mothers and offspring in large semi-natural enclosures and quantified offspring mass and social/exploratory behaviour. There were persistent negative effects of prenatal glucocorticoid exposure on offspring growth. We also observed lasting effects of prenatal glucocorticoid exposure on social behaviour: offspring from glucocorticoid-treated mothers had stronger social associations with other individuals, including with their mother and siblings, compared to offspring from control mothers. Association with their mother early in life did not mediate the effects of prenatal glucocorticoid exposure on offspring phenotype. These effects demonstrate that maternal stress can be an important mediator of variation in social behaviour in lizards, even overriding the influence of the social environment in the early postnatal period. This has potential implications for understanding how social groups form and are maintained.
Habitat heterogeneity and food availability in beaver-engineered streams foster bat richness, activity and feeding.
Moser V, Capitani L, Zehnder L … +8 more , Hürbin A, Obrist MK, Ecker K, Boch S, Minnig S, Angst C, Pomati F, Risch AC
J Anim Ecol · 2025 Dec · PMID 40952238 · Full text
As ecosystem engineers, Eurasian beavers (Castor fiber) modify aquatic and terrestrial ecosystems, which can benefit the biodiversity and community composition of plant and animal species. However, in contrast to aquatic...
As ecosystem engineers, Eurasian beavers (Castor fiber) modify aquatic and terrestrial ecosystems, which can benefit the biodiversity and community composition of plant and animal species. However, in contrast to aquatic taxa, beaver engineering impacts on terrestrial taxa, like bats, are so far largely overlooked. While it has been shown that bats prefer beaver-engineered ecosystems, the reason for this choice is poorly understood. We hypothesized that this preference may be associated with beaver-related changes in habitat characteristics and food availability. To address this knowledge gap, we recorded bat species richness, activity and feeding activity in eight beaver-engineered ecosystems (pool) with paired control sites without beavers (control) along the same stream in Switzerland. In addition, we collected data on food availability (arthropods) with arthropod flight interception traps and characterized habitat suitability with deadwood volume and vegetation surveys, as well as assessing canopy heterogeneity based on different digital height models. The nighly bat species richness increased from four to five species between control and pool sites. Bat activity increased 1.6 times and bat feeding activity 2.3 times in beaver-engineered systems compared to controls. These increases in richness and activity were explained by higher volumes of standing deadwood, higher canopy heterogeneity and higher arthropod abundance in beaver systems compared to controls. Overall, the volume of standing deadwood, a critical resource for bat roosting and foraging, had a stronger effect on bat species richness than canopy heterogeneity or arthropod availability. Bat feeding guilds (short-, mid-, long-range echolocators) responded differently to beaver-engineered habitat changes, with edge-hunting mid-range species benefiting the most. Our findings suggest that beaver engineering created structurally diverse habitats that supported a broader range of bat species. By modifying both habitat structure and prey abundance, beaver engineering affected bat activity, richness, and feeding activity directly and indirectly. These changes operated across aquatic-terrestrial boundaries, highlighting the cross-ecosystem influence and ecological complexity of ecosystem engineering.
Long-distance dispersal is asymmetrical with respect to age, sex and breeding latitude in a long-lived monogamous bird.
de Vries EHJL, Boom MP, Nolet BA … +2 more , Jongejans E, van der Jeugd HP
J Anim Ecol · 2025 Nov · PMID 40947672 · Full text
Although relatively rare, long-distance dispersal significantly impacts population persistence by facilitating range expansion, range shifts and genetic exchange. For individuals dispersing northwards, it may be a suitab...
Although relatively rare, long-distance dispersal significantly impacts population persistence by facilitating range expansion, range shifts and genetic exchange. For individuals dispersing northwards, it may be a suitable adaptation strategy to escape negative effects of climate change on their original breeding sites. In this study, we constructed a joint live encounter-dead recovery model under a Bayesian multistate framework to quantify long-distance dispersal between the Barents Sea, Baltic Sea and North Sea subpopulations of the Russia/Germany and Netherlands flyway population of the barnacle goose (Branta leucopsis), using long-term mark-recapture data of 22,413 individuals ringed between 1995 and 2023. Long-distance dispersal was strongly biased by age, sex and direction. Natal dispersal predominantly occurred in a northward direction, with 23.9% of juvenile males and 8.6% of juvenile females estimated to transition annually from the North Sea to the Barents Sea subpopulation. In contrast, breeding dispersal in the same direction in adults was minimal, estimated at only 0.49% and 0.21% for males and females respectively, and was not always distinguishable from temporary (moult-) migrations. Our model results were validated with data from 14 dispersing individuals, 9 of which were male, for whom the timing of breeding or moult was recorded. In all cases, dispersal was in a northward direction and the timing of breeding or moult of dispersers more closely resembled the timing of the receiving subpopulation than of the original subpopulation, but more so in males than in females. Our results support the notion of strong male-biased natal dispersal in monogamous waterbirds. Interestingly, despite substantial growth in the temperate breeding subpopulations during our study period, natal dispersal occurred predominantly in a northward direction at both individual and population levels. The unidirectional long-distance dispersal observed is expected to result from the unique flyway structure, where subpopulations with large differences in population size mix during wintering. Additionally, we also highlight the adaptability of dispersers, showing that barnacle geese can adaptively switch migration on and off, and that plasticity in the timing of breeding and moult may be larger in males than in females. We argue that this could be an additional explanation for the predominantly male-biased northward dispersal observed in barnacle geese.
Life-history trade-offs and environmental variability shape reproductive demography in a mountain ungulate.
White KS, Levi T, Hood E … +1 more , Darimont CT
J Anim Ecol · 2025 Dec · PMID 40937812 · Full text
Alpine ecosystems are changing rapidly with implications for the demography of alpine organisms. Here, we studied a sentinel species of mountain environments-the mountain goat (Oreamnos americanus)-to examine hypotheses...
Alpine ecosystems are changing rapidly with implications for the demography of alpine organisms. Here, we studied a sentinel species of mountain environments-the mountain goat (Oreamnos americanus)-to examine hypotheses about intrinsic and extrinsic drivers of reproductive demography using long-term data collected from individually marked animals across a broad spatiotemporal extent (n = 180 females, 3 study areas, 17 years) in coastal Alaska. Our analyses revealed the importance of life-history trade-offs and environmental variability on reproductive performance. The cost of reproduction, defined as the impact of reproducing the previous year on the probability of current year parturition, was high, especially for young, largely primiparous females (13%-32% reduction) and old, senescing individuals (27%-43% reduction); parturition of prime-aged individuals was relatively unaffected (2% reduction). Winter snow accumulation, which alters energetic expenditure and forage availability, exerted strong negative effects on reproduction (20%-35% reduction, depending on age). The relationship between temperature during the preceding summer's growing season and reproduction was likewise negative, although weaker and more variable (10%-15% reduction). Demographic modelling indicated that snow exerted stronger effects on population growth than summer temperature in part due to greater variability in snow versus temperature among years. Our analyses further revealed that reproductive performance did not affect subsequent survival of mothers or offspring, suggesting mountain goats employ a 'risk-sensitive', conservative reproductive strategy that prioritizes survival over reproduction. Taken together, these results fill an important knowledge gap by providing novel insights about the interplay between life-history trade-offs and environmental variation, and how they shape the reproductive demography of climate-sensitive wildlife.
Quantifying drivers of biodiversity change through increasing data availability and improved analytical frameworks.
Bonebrake TC, Yau EYH
J Anim Ecol · 2025 Oct · PMID 40931900 · Publisher ↗
Research Highlight: Guilbault, E., Sihvonen, P., Suuronen A., Huikkonen, I.-M., Pöyry, J., Laine, A.-L., Roslin, T., Saastamoinen, M., Vanhatalo, J. (2025). Strong context dependence in the relative importance of climate...
Research Highlight: Guilbault, E., Sihvonen, P., Suuronen A., Huikkonen, I.-M., Pöyry, J., Laine, A.-L., Roslin, T., Saastamoinen, M., Vanhatalo, J. (2025). Strong context dependence in the relative importance of climate and habitat on nation-wide macro-moth community changes. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.70107. Distributions of species are linked directly to extinction risk. Different threats can drive range contractions and reshape biodiversity patterns, yet their relative importance is rarely apparent. Additionally, the spatial and temporal distributions of species-and the resulting biodiversity patterns-are often incomplete or biased in existing datasets. Guilbault et al. (2025) present a productive framework to analyse biodiversity-monitoring data with spatiotemporal gaps by combining joint species distribution modelling (jSDM) with variance partitioning. Using a Finnish moth monitoring dataset, they demonstrate the effectiveness of this approach in identifying the dominant drivers of (and potentially, threats to) species' distributions. Their results reveal how these drivers vary across environments (environmental dependency) and between moths with different functional traits (functional dependency). Expanding this analytical framework to additional datasets with broad spatial and/or temporal coverage will further our understanding of how threats to biodiversity vary across time and space. Advances in modelling methods and the growing availability of high-quality data are substantially improving our capability to pinpoint and address threats to biodiversity-we hope that by leveraging results from such efforts, we may increase capacity for managing these threats to slow biodiversity loss.
Targeted 'infectiosome' for disease ecology: A new tool to answer old questions.
Gasparini J
J Anim Ecol · 2025 Oct · PMID 40931531 · Publisher ↗
Research Highlight: Bralet, T., Aaziz, R., Tornos, J., Gamble, A., Clessin, A., Lejeune, M., Galon, C., Michelet, L., Lesage, C., Jeanniard du Dot, T., Desoubeaux, G., Guyard, M., Delannoy, S., Moutailler, S., Laroucau,...
Research Highlight: Bralet, T., Aaziz, R., Tornos, J., Gamble, A., Clessin, A., Lejeune, M., Galon, C., Michelet, L., Lesage, C., Jeanniard du Dot, T., Desoubeaux, G., Guyard, M., Delannoy, S., Moutailler, S., Laroucau, K. and Boulinier, T. (2025). High-throughput microfluidic real-time PCR as a promising tool in disease ecology. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.70088. Disease ecology aims to understand the causes and consequences of the maintenance and transmission of pathogenic infectious agents. A crucial step in studying disease ecology is identifying the 'infectiosome', which I define as all infectious agents circulating among individuals, populations and the community of a given ecosystem. In a recent study, Bralet et al. (2025) propose a new, cheap and adaptable toolkit for determining a targeted 'infectiosome', which appears very useful in disease ecology approaches: high-throughput microfluidic real-time PCR (Htrt PCR). This method is a good alternative to costly metagenomic approaches and consists of running several dozen PCRs from a single tissue sample. This technique enables screening, from a single sample, the presence of dozens of targeted infectious agents: the targeted 'infectiosome', allowing one to answer several questions. For example, Bralet et al. (2025) applied this method to 274 seabirds and 80 mammals samples collected from the Southern Ocean islands and detected pathogenic infectious agents in new locations. The results also show that some species are potential 'reservoirs' of several infectious agents in this ecosystem. This method is really promising and can be easily adapted and used to test different hypotheses in disease ecology at the scales of the population and the community in other ecosystems, such as the urban ecosystem.
Relative brain size explains migratory/resident tendency in birds: Partial altitudinal migration in Asian house martins.
Yang YW, Hsu BY, Guo JC … +1 more , Hung CM
J Anim Ecol · 2025 Nov · PMID 40931398 · Publisher ↗
Migration is widespread among animals but varies in its manifestation with differences in direction, distance and obligatory nature. Understanding the evolution of migration requires insight into not only the development...
Migration is widespread among animals but varies in its manifestation with differences in direction, distance and obligatory nature. Understanding the evolution of migration requires insight into not only the development of this behaviour but also the loss of it. Partial migration, where some individuals within a population migrate while others stay, provides a unique opportunity to identify the proximate factors determining migratory/resident behaviours. In this study, we tested four hypotheses-the body size, arrival time, dominance and behavioural flexibility hypotheses-regarding phenotypic contributions to the loss or gain of migration in the Taiwan population of Asian house martins Delichon dasypus. This population exhibits partial altitudinal migration, with some martins remaining at mountain breeding grounds year-round and some migrating to lower elevations during winter. Our results most supported the behavioural flexibility hypothesis, which predicts that resident individuals tend to have larger brains than migratory ones, potentially associated with higher levels of foraging innovation. We argue that surviving in the harsh winter conditions in mountainous areas requires large brains, an energetically expensive trait that may further inhibit migration in resident Asian house martins. This creates a potential positive feedback loop where the demands of residency select for increased brain size while larger brains simultaneously facilitate residency. We also found that residents tended to have relatively smaller beaks, which likely help reduce heat loss in mountainous regions during winter. Our findings suggest that partial migration in Taiwan's Asian house martins resulted from the emergence of residency in large-brained individuals in a previously migratory population. We extend the behavioural flexibility hypothesis, traditionally applied to interspecific comparison, to demonstrate its explanatory power for intraspecific variations. Additionally, we integrate this hypothesis with selection imposed by high-elevation hypoxia to elucidate the evolutionary link between brain size and partial altitudinal migration.
Habitat and land-use intensity shape moth community structure across temperate forest and grassland.
Achury R, Staab M, Seibold S … +8 more , Müller J, Heidrich L, Püls M, Hacker H, Fonseca CR, Fischer M, Blüthgen N, Weisser W
J Anim Ecol · 2025 Nov · PMID 40926576 · Full text
Land-use change and intensification are major drivers of biodiversity loss, yet their effects on diversity have usually been studied within a single habitat type or land-use category, limiting our understanding of cross-...
Land-use change and intensification are major drivers of biodiversity loss, yet their effects on diversity have usually been studied within a single habitat type or land-use category, limiting our understanding of cross-habitat patterns. Moths, a species-rich taxon worldwide, represent a significant portion of the biodiversity in both temperate forests and grasslands, functioning as pollinators and herbivores. While increasing land-use intensity (LUI) in both habitats is expected to negatively impact moth assemblages, the strength of this effect remains uncertain. Moreover, land-use intensification interacts with broader environmental factors, such as weather conditions and the spread of artificial light at night (ALAN), but their combined effects on moth community diversity and turnover across habitats remain poorly understood. We sampled moth communities across 150 grassland and 150 forest plots along land-use gradients in Germany. We quantified plot- and landscape-scale LUI and tested the role of plant diversity, temperature and precipitation during the night of sampling and the preceding season, and ALAN in shaping moth diversity (standardized by coverage) along Hill numbers. Forests supported significantly higher moth abundance, biomass and diversity than grasslands, with habitat type being the main driver of moth community composition. LUI at the plot scale had contrasting effects on moth abundance, increasing it in forests but reducing it in grasslands. Impacts of LUI were more pronounced at the landscape level, reducing moth diversity particularly in areas dominated by grasslands. Plant diversity and temperature were key determinants for moth communities, increasing alpha diversity across diversity metrics, that is Hill numbers. ALAN had no significant influence on moth abundance or biomass but significantly decreased Simpson diversity. Beta diversity increased with geographic distance, habitat change and LUI but decreased with weather differences among plots. Our results highlight the interplay between LUI, habitat type and abiotic factors in shaping moth communities across large spatial scales. Effective conservation strategies should consider maintaining habitat heterogeneity and promoting plant diversity, particularly in temperate habitats exposed to high land-use intensification.
Habitat structure and predator diversity jointly shape the arrangement of predator-prey networks.
Michalko R
J Anim Ecol · 2025 Nov · PMID 40923560 · Publisher ↗
Research Highlight: Chen, J., Wang, M. Q., Luo, A., Zhang, F., Chesters, D., Liu, S., Li, Y., von Oheimb, G., Kunz, M., Zhou, Q. S., Bruelheide, H., Liu, X., Ma, K., Schuldt, A., & Zhu, C. D. (2025). Bottom-up and top-do...
Research Highlight: Chen, J., Wang, M. Q., Luo, A., Zhang, F., Chesters, D., Liu, S., Li, Y., von Oheimb, G., Kunz, M., Zhou, Q. S., Bruelheide, H., Liu, X., Ma, K., Schuldt, A., & Zhu, C. D. (2025). Bottom-up and top-down effects combine to drive predator-prey interactions in a forest biodiversity experiment. Journal of Animal Ecology. https://doi.org/10.1111/1365-2656.70103. Habitat structure influences predator-prey and predator-predator interactions and may interact with predator diversity to determine food-web dynamics. However, only a limited number of studies have investigated how habitat structure and predator diversity jointly shape the predator-prey network. Using molecular analysis of spider gut content, Chen et al. (2025) investigated how various measures of tree diversity and spider phylogenetic diversity shaped the spider-prey network. The spider-prey network was characterized by prey richness, generality, vulnerability and niche overlap in young forest canopies. When considering all spiders together, both tree and spider diversity led to increased prey richness, prey vulnerability and niche overlap, but generality was consistent. However, when spiders were divided into two foraging guilds, web-builders and hunters, the factors driving the food-web structure varied between them. Although both spider diversity and habitat structure affected the spider-prey network, their relative importance differed between the two guilds. For web-builders, phylogenetic diversity was the main driver and high phylogenetic diversity of spiders led to an increase in prey richness, generality, prey vulnerability and niche overlap. For hunting spiders, the tree vertical diversity was an important factor shaping the network structure and higher vertical diversity led to a reduction in prey richness and diet breadth. Overall, the results show that the bottom-up effect of tree diversity and the top-down effect of spider diversity combined to jointly determine the structure of the spider-prey network. However, the impact of tree diversity and phylogenetic diversity of spiders on the structure of the spider-prey network was conditioned by a measure of tree diversity and spider foraging guilds. The results have important implications for forest management, and foresters should aim to maintain heterogeneous forests rather than simple monocultures to enhance predation pressure by spiders on pests and to ensure ecosystem resilience.
Social network dynamics under experimental manipulations of predation risk and food abundance in wild rock hyraxes.
Bordes CNM, Ammeter M, Lu C … +4 more , Beukeboom R, Goll Y, Bourdiol J, Ilany A
J Anim Ecol · 2025 Sep · PMID 40908627 · Publisher ↗
Understanding how animals respond to ecological constraints is crucial for interpreting the dynamics of social networks in the wild. We investigated how experimentally induced changes in perceived predation risk and food...
Understanding how animals respond to ecological constraints is crucial for interpreting the dynamics of social networks in the wild. We investigated how experimentally induced changes in perceived predation risk and food abundance influence the social behaviour of wild rock hyraxes (Procavia capensis), using experimental manipulations and a meta-analytical framework. We used proximity sensors, trail cameras and observations to record multiple aspects of social interactions. Elevated predation risk caused hyraxes to prioritize spatial adjustments over social rewiring, leading to a slight decrease in sociality and increased social stability within groups. Bachelor males and adult females exhibited greater behavioural adjustments, with solitary individuals interacting more with social groups to mitigate predation risk. In contrast, increased food abundance led to forced proximity at feeding patches, promoting social interactions and clustering within groups. Bachelor males connected social units without increasing network transitivity. Both manipulations highlighted that hyraxes preserve group structure and individual social bonds while exhibiting compensatory social behaviours. Our findings emphasize the possible role of space use in shaping short-term social network dynamics and underscore the stability of animal social structures under mild environmental perturbations. This study also demonstrates the utility of a meta-analytical approach for disentangling context-dependent social responses in complex ecological systems.
Harnessing 50 years of tick population genetics: Choosing the right molecular tool for contemporary research.
Barton X, Fontaine JB, Tobe SS … +1 more , Oskam CL
J Anim Ecol · 2025 Nov · PMID 40899772 · Full text
Ticks are ectoparasites of major medical, veterinary and ecological importance, transmitting a wide range of pathogens to humans, companion animals and livestock. Understanding the population structure of ticks is essent...
Ticks are ectoparasites of major medical, veterinary and ecological importance, transmitting a wide range of pathogens to humans, companion animals and livestock. Understanding the population structure of ticks is essential for uncovering patterns of pathogen transmission, and population genetics provides a powerful method for this purpose. Tick population studies are uniquely challenging as their biology is shaped by complex interactions between hosts, microbiome and environmental factors. The choice of population genetic tools is crucial, as different methods offer varying levels of cost, throughput, resolution and accessibility, which can significantly influence the quality and scope of results. This review traces the evolution of molecular tools in tick population genetics, from early allozyme electrophoresis in the 1970s to advanced whole genome sequencing (WGS) technologies. It critically evaluates key methodologies, including allozyme electrophoresis, random amplified polymorphic DNA (RAPD), microsatellites (STRs), amplified fragment length polymorphisms (AFLP), sequence typing, restriction-site associated DNA sequencing (RADseq) and WGS, highlighting their strengths, limitations and applications. By offering a practical guide to these tools, this review helps researchers select the most appropriate methods for their studies and allows interpretation of results from older tools in the context of modern research. Sequence typing and RADseq currently provide the best balance of cost and practicality, while WGS has great potential once sequencing costs decline. This resource empowers researchers to make informed decisions, maximise the impact of their work and gain deeper insights into disease vector population structure.
Limited inbreeding avoidance at the gamete level despite inbreeding depression in Atlantic salmon (Salmo salar).
Graziano M, Solberg M, Glover KA … +5 more , Taylor M, Sørvik AGE, Murray D, Immler S, Gage MJG
J Anim Ecol · 2025 Nov · PMID 40899694 · Full text
Inbreeding and the associated increase in homozygosity and potential accumulation of deleterious alleles may reduce fitness in a process known as inbreeding depression. Mechanisms to mitigate reproduction between close r...
Inbreeding and the associated increase in homozygosity and potential accumulation of deleterious alleles may reduce fitness in a process known as inbreeding depression. Mechanisms to mitigate reproduction between close relatives, ranging from pre-mating mate choice to post-mating gamete selection, have evolved across taxa. In external fertilisers like Atlantic salmon (Salmo salar), where females have limited control over paternity, mechanisms of inbreeding avoidance can be expected to evolve at the gamete level. Philopatric Atlantic salmon may run the risk of breeding between relatives, particularly in small populations, and frequent escapes from aquaculture settings are augmenting the chances of adults from the same sibling cohort overlapping in the wild, raising potential ecological and sustainability concerns. Moreover, the presence of inbreeding avoidance mechanisms between full siblings in externally fertilising fish is currently untested. This study tested post-mating inbreeding avoidance mechanisms in domesticated Atlantic salmon. In a paired breeding design, we compared sperm motility parameters in sibling and non-sibling ovarian fluid, and assessed fertilisation and hatching success, growth rate and paternity in sperm competition trials between sibling and non-sibling males. Sperm activated in ovarian fluid of sibling females showed lower values of motility-related parameters and led to an average of 18% reduction in fertilisation rates in the resulting crosses. Furthermore, offspring from sibling crosses were smaller before the onset of sexual maturation. However, we found no difference in survival rates between sibling and non-sibling cross offspring. Besides, when sperm from sibling and non-sibling males were competing simultaneously for the same egg batch, we found no influence of this on paternity. Our findings reveal the presence of post-mating inbreeding avoidance at the gamete level in Atlantic salmon, but its effects are limited in competitive scenarios. Our results have implications for salmonid conservation and aquaculture, where small natural or closed domestic strains may both display a degree of inbreeding. Mating between escaped domestic and wild salmonids could favour admixed over wild or feral crosses if an inbreeding avoidance mechanism is present; although this remains to be tested in more outbred crosses.
Early-growth trajectories affect juvenile survival, age at first reproduction and lifetime fitness in a long-lived seabird, the little penguin.
Wintz J, Joly N, Jenouvrier S … +3 more , Viblanc VA, Chiaradia A, Saraux C
J Anim Ecol · 2025 Nov · PMID 40887974 · Full text
Early environmental conditions experienced during juvenile growth are known to have marked effects on adult phenotypes in animal populations. Yet, the life-history outcomes of variable growth strategies have rarely been...
Early environmental conditions experienced during juvenile growth are known to have marked effects on adult phenotypes in animal populations. Yet, the life-history outcomes of variable growth strategies have rarely been investigated in wild populations. The aim of this study was to examine the natural variation of growth patterns displayed within a seabird population and assess their impact on juvenile survival, age at first reproduction, lifetime reproductive outputs (LRO) and longevity. Using a 26-year study on the ecology of little penguins, we compiled over 2200 chick growth curves and defined 11 growth parameters classified by magnitude, form and rate. Although the growth curves formed a continuum according to these 11 growth parameters, non-supervised statistical clustering showed that growth trajectories clustered into three main groups: fast, slow and light. Fast chicks (n = 48%) attained the highest maximum mass in the shortest amount of time, whereas slow chicks (n = 33%) stood out by a prolonged (+7 days, i.e. +13% in comparison to fast chicks) and irregular period of juvenile growth. Finally, light chicks (n = 19%) reached low maximum and fledging masses (~-350 g; -37% and -36% of fast and slow chicks). We tested for the effects of chick growth parameters on subsequent annual vital rates estimated through capture-mark-recapture methods as well as longer term effects on life-history outcomes using Markov chain models. Fast and slow individuals had the highest survival rates from hatching to yearling age (19% and 17%, respectively), while light chicks were at a disadvantage during this initial period (3% survival). Fast individuals reproduced 12% earlier (2.6 years old) than slow individuals, had 12.5%-88% greater longevity (up to 21 years old), and produced 1.2-3.8 times more eggs over their lifespan than slow and light individuals, respectively. Fast chicks reached maturity faster and produced more offspring during their lifetime without discernible negative effects to their longevity, highlighting possible silver spoon effects.
Freeze-tolerant frogs accumulate cryoprotectants using photoperiod: A potential ecological trap.
Neptune TC, Koester DC, Benard MF
J Anim Ecol · 2025 Nov · PMID 40887962 · Full text
Climate change is disrupting the reliability of photoperiod as a cue signalling seasonal changes in temperature. Temperate and Arctic species are especially vulnerable to this mismatch between photoperiod and temperature...
Climate change is disrupting the reliability of photoperiod as a cue signalling seasonal changes in temperature. Temperate and Arctic species are especially vulnerable to this mismatch between photoperiod and temperature because winters are warming more rapidly in these areas relative to the rest of the world. Organisms relying on autumn photoperiods to trigger physiological adaptations to survive winter may incorrectly time the onset of winter and exhibit maladaptive responses. We exposed a freeze-tolerant amphibian, the eastern gray treefrog (Hyla versicolor), to variation in photoperiod and measured its cryoprotectant reserves (glycogen stored in the liver), thermal tolerance and post-metamorphic growth. We raised treefrogs under three photoperiods starting at egg development through the juvenile stage in the context of a warm growing environment. By the end of the experiment, juveniles were under photoperiods simulating late June, late September and early November (early, average and late, respectively). We show that gray treefrogs under the late-season photoperiod accumulated large reserves of cryoprotectants (i.e. 'antifreeze') and exhibited greater cold tolerance. Treefrogs raised under the late-season photoperiod had both higher concentrations of glycogen in liver tissue and larger livers compared to individuals from the other photoperiods. This resulted in treefrogs from the late-season photoperiod exhibiting 13.8 times more total liver glycogen compared to treefrogs in the early-season photoperiod and 8.2 times more reserves than treefrogs in the average-season photoperiod. Treefrogs under a late-season photoperiod also exhibited a lower critical thermal minimum but not critical thermal maximum compared to treefrogs from the early-season photoperiod. However, treefrogs in the late-season photoperiod also had reduced size-specific growth rates during the juvenile stage, indicating a potential cost to these physiological overwintering strategies. Photoperiod alone, without decreases in temperature, induced all of these physiological changes. Our results highlight the importance of photoperiod as a cue for overwintering preparation in a widespread North American amphibian. However, as climate change continues to expand the growing season, organisms relying on photoperiod to prepare for overwintering may therefore enter an ecological trap where photoperiod no longer accurately signals seasonal changes in temperature.
Predator activity, proactive anti-predator strategies and nesting phenology produce a dynamic landscape of risk to tundra goose reproduction.
Johnson-Bice SM, Warret Rodrigues C, Gamblin HEL … +2 more , Baldwin FB, Roth JD
J Anim Ecol · 2025 Nov · PMID 40887958 · Full text
Birds generally rely on proactive anti-predator strategies when selecting nest sites, as they have limited options to adapt to changing levels of risk once incubation begins. Arctic waterfowl often nest colonially as an...
Birds generally rely on proactive anti-predator strategies when selecting nest sites, as they have limited options to adapt to changing levels of risk once incubation begins. Arctic waterfowl often nest colonially as an anti-predator strategy, but dispersed-breeding species may use other proactive strategies, such as nesting in areas perceived to be safer. However, empirical links between spatial patterns of predation risk and nest habitat selection or success are needed to better understand how predator activity shapes Arctic waterfowl reproduction. Using activity data from the main cursorial nest predators, Arctic and red foxes (Vulpes lagopus, Vulpes vulpes), and aerial predators, we evaluate the influence predator activity has on Canada goose (Branta canadensis interior) nest habitat selection and success, and how nesting phenology mediates these effects. We compared habitat selection models fit to (i) goose nest locations and (ii) fox locations obtained from GPS collars and found that geese and foxes displayed nearly opposite patterns of selection for the same landscape traits. Geese selected sites that minimized their probability of encountering foxes while also maximizing their ability to detect foxes. Spatial predictions of fox activity revealed nests located in areas with higher probability of fox use had lower nest success, indicating fox space-use patterns reflect predation risk. Landscape heterogeneity influenced both fox and goose nest habitat selection patterns and, consequently, spatial variation in predation risk and reproductive success. Aerial predators appeared to have a lesser effect on spatial patterns of goose nest habitat selection and success. Spatial patterns of nest success were, however, strongly influenced by nesting phenology. Nests initiated earlier had a greater probability of successfully hatching, but these patterns depended on location; the benefits of nesting early decreased in areas of high fox activity. Our study demonstrates the mechanisms by which nesting phenology, predator activity and landscape heterogeneity interact to shape bird reproduction and provides an empirical demonstration of how our understanding of predation risk is enhanced by integrating both spatial and temporal dynamics.
Herbivory mediates the response of below-ground food webs to invasive grasses.
Junod MF, Cordero I, Chinn N … +8 more , Firn J, Holmes J, Klein M, Lebbink G, Nielsen UN, Schütz M, Zimmermann S, Risch AC
J Anim Ecol · 2025 Oct · PMID 40883959 · Full text
Below-ground food webs in grasslands are affected by both above-ground herbivory and invasive plant species. However, the combined effects of these factors on soil organisms and their interactions with plant communities...
Below-ground food webs in grasslands are affected by both above-ground herbivory and invasive plant species. However, the combined effects of these factors on soil organisms and their interactions with plant communities remain poorly understood. We investigated how the invasive African lovegrass (ALG) influenced below-ground food webs in south-eastern Australian grasslands under different herbivory regimes. Using experimental exclosures, we established four treatments varying in herbivore presence (all animals present, non-native mammals excluded, all mammals excluded, all above-ground dwelling animals excluded) across sites dominated either by native kangaroo grass (KG; native sites) or co-dominated by KG and ALG (invaded sites). After 4 years, our results revealed that invasive grasses significantly altered the abundance and structure of soil bacteria, fungi, nematodes, arthropods and earthworms. These effects intensified along the gradient of herbivore exclusion. In parallel with herbivore exclusion, accumulated plant litter shifted decomposition from bacterial to fungal-dominated, driven by changes in soil temperature, moisture and substrate, ultimately reshaping the soil biota assemblages. Herbivory, particularly by both native and non-native mammals, mitigated many of the adverse impacts of grass species invasion, with native and non-native mammals acting additively. These findings underscore the intricate interplay between invasive grasses and herbivory, emphasising the importance of integrated management strategies to maintain the ecological balance of grassland ecosystems.
Enhanced thermoregulation abilities of shortfin mako sharks as the key adaptive significance of regional endothermy in fishes.
Tokunaga S, Chiang WC, Nakamura I … +2 more , Matsumoto R, Watanabe YY
J Anim Ecol · 2025 Nov · PMID 40878923 · Full text
Some large, wide-ranging teleosts and elasmobranchs are converged to have regional endothermy, retaining metabolic heat via vascular countercurrent heat exchangers. Yet, their adaptive significance remains debated. While...
Some large, wide-ranging teleosts and elasmobranchs are converged to have regional endothermy, retaining metabolic heat via vascular countercurrent heat exchangers. Yet, their adaptive significance remains debated. While previous studies proposed potential benefits of elevated body temperature, enhanced controllability of body temperature enabled by heat exchangers may also be important. Some endothermic teleosts (e.g. bigeye tuna) alter rates of body temperature change depending on dive phases to maximize foraging time in deep, cold waters while minimizing recovery time in shallow, warm waters. However, whether endothermic elasmobranchs possess similar abilities remains unclear. Using animal-borne tags, we recorded diving behaviours and muscle temperatures of shortfin mako sharks, a possible elasmobranch equivalent to bigeye tuna. Warming and cooling rates were estimated with a heat exchange model. Further, we conducted literature-based, phylogenetically informed comparative analyses of heat exchange rates across 25 fish species (mass range, 0.01-1600 kg). All four mako sharks repeatedly dived below the thermocline with ambient temperature changes of up to 7-14°C. On average, muscle temperatures were 1.5-3.9°C warmer than the ambient water. Two individuals dived deep (up to 286-327 m) and showed a 14-47 times higher warming rate than cooling rate, whereas the other two individuals that dived shallowly exhibited one to two times differences. One individual warmed its muscle above sea surface temperature before a deep dive, possibly preparing for the coming deep excursion using internal heat sources. Comparative analyses showed that the ratio of warming to cooling rate and its range across individuals was larger in endothermic bigeye tuna, swordfish and mako sharks than in most other fishes. Our results demonstrate that enhanced temperature controllability has convergently evolved among some endothermic teleosts and elasmobranchs that inhabit low-to-middle latitude waters with strong thermal gradients. By contrast, some other endothermic species (e.g. salmon sharks and Atlantic bluefin tuna) that migrate to subpolar waters are specialized for body temperature elevation. We propose that the controllability and elevation of body temperature have different adaptive significance, reflecting species' habitats and foraging ecology. Our findings help explain the diversity and success of endothermic fishes as apex predators across the world's pelagic oceans.
Across the edge: Spatial segregation drives community structure in tri-trophic multilayer networks at a forest-grassland edge.
Negrello-Oliveira H, Tovar-Marquez J, de Souza Mendonça Júnior M
J Anim Ecol · 2025 Nov · PMID 40874832 · Full text
Examining spillover between habitat boundaries offers a key opportunity to understand how neighbouring habitats may affect each other. Although extensively studied, ecological responses at forest-grassland edges are vari...
Examining spillover between habitat boundaries offers a key opportunity to understand how neighbouring habitats may affect each other. Although extensively studied, ecological responses at forest-grassland edges are variable across trophic levels and their underlying interactions. Thus, tackling the subject from a multitrophic perspective may yield valuable insights into how energy may flow across forest-grassland edges. We asked whether a forest-grassland edge functions as an ecological barrier or a continuum for species interactions across space and trophic levels. We also examined whether species influence in the network is better explained by their distribution across the edge (spatial structure) or by their connections with other species (modular structure). We studied a tri-trophic (prey-consumer-parasitoid) antagonistic system at Atlantic Forest and Pampa Grassland edges, arranged in fire-prone mosaics in southern Brazil. Using network dissimilarity and multilayer approaches, we investigated species and trophic-level contributions to connectivity across the spatial/modular landscape by sampling cavity-nesting hymenopterans and their interactions across a distance gradient from the habitat edge We found spatially segregated modules confined to each habitat, indicating that the edge likely functions as an ecological barrier. Network dissimilarity peaked in cross-habitat comparisons, reinforcing the separation between forest and grassland ecosystems. While all trophic levels were less adaptable to shifts between habitats and modules, they showed greater adaptability across spatial strata within each habitat. The main factor determining species influence throughout the network was their ability to move across spatial layers, although trophic-level and habitat subgroups also responded to other variables. Cross-edge species had greater influence in connecting habitats internally than in serving as energy pathways between them. Our findings reveal that Atlantic Forest-Pampa Grassland edges likely constitute an ecological barrier network-wise. However, edge effects increasing interaction richness and abundance may highlight the importance of edge proximity to key species promoting within-habitat network cohesion. Our results highlight how network dynamics may span across habitat edges with significant species turnover, calling for active conservation strategies to prevent forest encroachment and maintain grassland habitats-while recognising that disturbances within the roughly 40-m edge effects zone could potentially cascade inward, influencing species and interactions beyond the edge.
Prey bioluminescence-mediated visual luring in a sit and wait predator.
Yip HY, Blamires SJ, Liao CP … +1 more , Tso IM
J Anim Ecol · 2025 Oct · PMID 40867039 · Publisher ↗
As behavioural and physiological processes can be costly for animals to employ, deception and other dishonest strategies may become necessary for sit-and-wait predators. Sheet-web spiders Psechrus clavis have been known...
As behavioural and physiological processes can be costly for animals to employ, deception and other dishonest strategies may become necessary for sit-and-wait predators. Sheet-web spiders Psechrus clavis have been known to use their body colour and webs as visual cues to deceptively lure and immediately consume lepidopteran insects. However, they do not immediately consume trapped male fireflies Diaphanes lampyroides; instead, the spiders retain them in their webs while the fireflies continue to emit their bioluminescent signal for up to an hour. This observation raises the question: can the spiders exploit prey signals to attract additional prey, thereby enhancing their foraging success? We hypothesized that such a unique prey-handling strategy serves to enhance P. clavis' foraging productivity by exploiting the prey's own signal as a deceptive lure. To test this hypothesis, we performed a field manipulative study using light emitting diodes (LEDs) resembling the bioluminescent signal of D. lampyroides and evaluated the responses of fireflies and other prey using infrared video cameras. We found that the presence of the simulated firefly signal significantly increased prey attraction and interception rates within P. clavis webs. We also found male D. lampyroides to comprise the bulk of the additional prey obtained. We speculate that this enhanced foraging return allows P. clavis to reduce its energetic and nutritional investment in insect-attracting body coloration. This study sheds new light on the ways that nocturnal sit-and-wait predators can rise to the challenges of attracting prey and provides a unique perspective on the complexity of predator-prey interactions.
The gut microbiome shapes latitudinal differences in host immunity and pathogen load in a damselfly.
Theys C, Jorissen S, Janssens L … +4 more , Tüzün N, Decaestecker E, Verheyen J, Stoks R
J Anim Ecol · 2025 Oct · PMID 40842382 · Publisher ↗
Latitudinal patterns in fitness-related traits within species are receiving increased attention as these inform how high-latitude populations may evolve in response to global warming. The underlying mechanisms for these...
Latitudinal patterns in fitness-related traits within species are receiving increased attention as these inform how high-latitude populations may evolve in response to global warming. The underlying mechanisms for these latitudinal trait patterns remain poorly understood, and recently the gut microbiome has been suggested to be a potentially important proximate driver of these patterns. We investigated the novel idea of whether the gut microbiome drives latitudinal differences in immune function and pathogen load. To test this idea, we performed a reciprocal gut microbiome transplant between slow-paced, high-latitude (southern Sweden) and fast-paced, low-latitude (southern France) populations of Ischnura elegans damselflies. The transplants were conducted in the laboratory between high- and low-latitude larvae, at both a colder and warmer thermal regime, whereafter larvae were exposed to Escherichia coli, a widespread pathogenic bacterium in aquatic ecosystems. During the experiment, larval mortality, growth rate, phenoloxidase (PO) level (a measure of immune function), E. coli burden (a measure of pathogen load) and the gut microbiome diversity (α-diversity) and community compositions (β-diversity) were analysed. Exposure to the pathogen increased mortality, especially under warming. Our results confirmed latitude-associated thermal adaptation and a faster pace of life of the low-latitude larvae, which was associated with a lower immune function (lower activity of PO), consistent with previous findings and now showed this to be linked to a higher pathogen load (higher E. coli body burden). Moreover, our results provided the first experimental evidence that the gut microbiome causally contributed to latitudinal differences in the host's immune function and pathogen load. As latitudinal patterns in the microbiome are widespread, this may be an important yet ignored proximate driver of the latitudinal patterns in immune function and pathogen load.
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