Journal of Animal Ecology最新文献

{"title":"Does a lack of juveniles indicate a threat? Understanding body size distributions in a group of long-lived vertebrates.","authors":"Donald T McKnight, Deborah S Bower, Ellen Ariel, Stephen Beatty, Simon Clulow, Marilyn Connell, Annette R Deppe, Sean Doody, Alastair Freeman, Arthur Georges, Samantha L Hannabass, Ethan C Hollender, Hunter Howell, Aaron Krochmal, Day B Ligon, Eric Munscher, Eric J Nordberg, Timothy C Roth, Anthony Santoro, Jason Schaffer, Angela Simms, Ricky-John Spencer, Paul Stone, Kameron C Voves, Andrew D Walde, Skye Wassens, Michael A Welsh, Nick S Whiterod, Wytamma Wirth, James U Van Dyke","doi":"10.1111/1365-2656.70093","DOIUrl":"https://doi.org/10.1111/1365-2656.70093","url":null,"abstract":"<p><p>Turtles are declining globally, and absences of juveniles during surveys are often interpreted as evidence of threats to early life stages. In Australia, for example, it is widely argued that a low number of juveniles is likely due to nest predation by introduced red foxes (Vulpes vulpes). However, small sample sizes within populations, low detectability of juveniles and turtles' long lifespans often confound the conclusion that a paucity of juveniles indicates a declining population. Because turtles have long reproductive lifespans, we might intuitively expect most turtle populations to be heavily weighted towards large individuals, but a 'typical' or 'healthy' size distribution for turtle populations has not been well established. Therefore, we collated data on 41,021 freshwater turtles from 38 species and 428 populations located in parts of Australia both with and without introduced foxes, as well as populations in the United States of America, which naturally have raccoons (Procyon lotor), foxes and other nest predators. We examined population-level body size distributions to establish a baseline for 'typical' turtle populations and test whether populations that are exposed to introduced foxes have proportionately fewer juveniles compared to both AU populations that lack introduced foxes and USA populations that are naturally exposed to nest predators. We found that most turtle populations in AU and the United States were heavily skewed towards adults and had few juveniles, regardless of the presence of foxes or other nest predators. There were, however, clear differences among population survey methods: those that target shallow areas (e.g. crawfish traps) tended to capture proportionately more juveniles, and small sample sizes (∼<50) often produced inaccurate representations of size distributions. Additionally, we used a simulation to demonstrate that, given common turtle life history parameters, even stable populations should generally have low proportions of juveniles. Based on our results, we encourage caution when interpreting turtle size distributions. A small number of juveniles does not inherently suggest that a population is declining due to high egg and/or juvenile mortality, and researchers should pay careful attention to the biases in their methods and strive to capture a minimum of 50-100 turtles before drawing inferences.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144731076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Canopy ants are out in the cold in temperate forests.","authors":"Rebecca A Senior","doi":"10.1111/1365-2656.70110","DOIUrl":"https://doi.org/10.1111/1365-2656.70110","url":null,"abstract":"<p><p>Research Highlight: Kirchner, Michelle; Sorenson, Clyde; Youngsteadt, Elsa (2025). Too cold to handle: Climatic constraints on arboreal ants in temperate forests. Journal of Animal Ecology. Ants are among the most abundant animals on the planet and they have a huge impact of ecosystems worldwide. Being small-bodied ectotherms, their growth, survival and reproduction is closely tied to the temperatures they experience (the microclimate), and hence the thermal physiology of different ant species determines their global and regional distribution and is subject to change under climate warming. Forest habitats present a significant additional climate gradient from ground to canopy, and its implications for tropical ant species have been reasonably well explored. Yet these findings cannot easily be easily applied to temperate forests, where seasonal variation in temperature and vegetation could mean very different things for ant communities. Kirchner, Sorenson, & Youngsteadt (2025) address this research gap by measuring the thermal tolerance of ants collected from the ground and canopy, across seasons, and alongside measurements of air and nest temperatures. As elsewhere, ants that experience a broader range of temperatures-in this case, canopy ants-have a broader thermal tolerance than those experiencing more stable temperatures-the ground-dwelling ants. Ants from both strata adapted their cold tolerance to cope with winter cold, while heat tolerance did not change, in line with previous evidence that heat tolerance is a less labile trait. Perplexingly, however, canopy ants were less tolerant of winter cold despite being far more exposed to extreme cold. Thus, this paper provides an intriguing insight into how ecophysiological rules play out for ants across the vertical gradient of temperate forests, suggesting that canopy ants here are more limited by tolerance of winter cold. This could suggest that the diversity of temperate forest canopies may increase as winters become less extreme, which could have important implications for temperate forest ecosystems.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144731075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Guild diversity impacts demographic outcomes of novel species interactions following range shifts.","authors":"Michael O'Connor, Lesley T Lancaster","doi":"10.1111/1365-2656.70108","DOIUrl":"https://doi.org/10.1111/1365-2656.70108","url":null,"abstract":"<p><p>Novel competitive interactions between native and range shifting species can precipitate local extinction of native species. However, increased biological complexity within recipient communities may prevent native species loss by decreasing the strength of novel competition experienced by any one species. This phenomenon, termed 'biotic resistance', is commonly applied in invasion ecology, but has received little attention in the context of climate induced range shifts. Here we investigate the effects of biotic resistance in competition between resident native and range-shifting damselflies in a region of Scotland newly colonised by the range-shifter, using competitive mesocosm treatments across multiple life stages and experimental temperatures. Our focal native species (Lestes sponsa) was unaffected by increasing competitive complexity as larvae, showing no fitness benefits in multispecies treatments compared to intraspecific or even interspecific scenarios in the presence of the range shifter. However, multispecies competition with both native and range-shifting species improved adult survival of our focal native species at higher temperatures, compared to interspecific competition with just the range shifter. For our focal range-shifting species (Ischnura elegans), larval growth rate was significantly reduced in multispecies treatments compared to intraspecific or two-species interspecific scenarios, yet adult range shifter survival showed no decrease in multispecies treatments. Furthermore, range shifter larvae displayed improved survival and growth in colder temperatures, compared to a lack of any temperature effects on adult survival. These results suggest that biotic resistance may alleviate the competitive impacts of range shifters on native communities by providing a life stage-dependent benefit to native species while simultaneously decreasing the fitness of range shifters. However, shifting temperatures can cause this interaction to swap between competition and facilitation, creating an environmentally dependent scenario that may benefit both range shifters and resident species, promoting the maintenance of diversity in high latitude communities.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144707556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tropical fishes can benefit more from novel than familiar species interactions at their cold-range edges.","authors":"Angus Mitchell, Chloe Hayes, Ericka O C Coni, David J Booth, Ivan Nagelkerken","doi":"10.1111/1365-2656.70100","DOIUrl":"https://doi.org/10.1111/1365-2656.70100","url":null,"abstract":"<p><p>Animals extending their biogeographic ranges poleward under global warming often interact with local species for limited resources such as food and shelter. Whether such novel species interactions facilitate or inhibit range extensions remains largely unknown. We evaluated how range-extending tropical and co-shoaling temperate fishes modify their behaviours (aggression, foraging and anti-predator) along a 2000-km latitudinal gradient encapsulating tropical, subtropical and temperate reefs in a global ocean warming hotspot. All five tropical fish species showed increased anti-predator behaviours and decreased bite rate at their novel temperate range compared to their native tropical and subtropical ranges. However, when shoaling with temperate fishes, three of five tropical fish species had higher bite rates and all five tropical fish species spent less time sheltering compared to tropical-only shoals, irrespective of biogeographic region. In their subtropical ranges, tropical fish were more aggressive towards co-shoaling temperate fish compared to their poleward novel cold ranges. This increased tropical fish aggression resulted in increased fleeing responses by the two temperate fishes at their subtropical warm trailing edges compared to their warm- and cold-temperate core ranges. Our findings suggest that tropical fish species trade-off foraging efficiency for anti-predator behaviour in their novel warm- and cold-temperate ranges, independent of shoaling interactions. However, shoaling with temperate species can increase the foraging efficiency of tropical fishes, which may be a mechanism (phenotypic plasticity) that enhances their performance at their leading temperate range edges. Since novel species interactions enhanced the behavioural performance of some tropical fishes, we conclude that behavioural interactions between range-extending and local species can facilitate successful range extensions of some species into novel environments.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144698644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Temporal niche differentiation often leads to priority effects rather than coexistence: Lessons from a marine midge.","authors":"Runa K Ekrem, Charlotte de Vries, Tobias S Kaiser, Hanna Kokko","doi":"10.1111/1365-2656.70094","DOIUrl":"https://doi.org/10.1111/1365-2656.70094","url":null,"abstract":"<p><p>While niche differences aid coexistence, the role of temporal niches is complex. A recent study (Stump & Vasseur, 2023) casts doubt on the idea that species coexist easily if they partition abiotic niches that vary in time. The storage effect, which aids coexistence, requires that species differ in what is a 'good year', and that the benefits that the currently common species can draw from its own good year become limited due to intraspecific competition. The recent re-evaluation of temporal niches considered Allee effects only fleetingly. We complement their work by providing a case study of the marine midge Clunio marinus, where coexistence appears to occur in nature, is associated with a strong difference in timing traits, and also features Allee effects because rare timing phenotypes emerge with limited mating opportunities. The larvae develop in the sea, and adults emerge and mate during the lowest low tides. These tides coincide with either the full or the new moon, and genetically determined strains use either one of them, or both, for emergence. A 'good year' in this system translates into a particular low tide. Allee effects create strain-specific good tides if the risk of hybridization is greater for the currently rare strain, which mates more often with another strain, than the currently common strain. We are able to investigate this effect by varying the effects of hybridization in our model of Clunio biology. Temporal niches, mate-finding Allee effects, hybridization possibilities and a potential growth-survival tradeoff do not easily combine to yield stable coexistence. Most factors instead promote positive frequency dependence, leading to priority effects. Ontogenetic niche shifts among larvae deviate from this result: if suitably timed, they are able to concentrate competition in a coexistence-promoting manner. Our study thus complements and strengthens Stump and Vasseur's conclusion that a finding of temporal niche differentiation should not be straightforwardly assumed to be an explanation for the coexistence of two or more morphs or species. We encourage linking temporal niche studies with those of priority effects, as well as the study of other coexistence mechanisms that may operate within systems that feature temporal niches.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144674855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Host avoidance and resistance vary independently and are specific to parasite genotype.","authors":"Caroline R Amoroso, Adianna Lockwood-Shabat, Andreas Kamali, Amanda K Gibson","doi":"10.1111/1365-2656.70109","DOIUrl":"10.1111/1365-2656.70109","url":null,"abstract":"<p><p>Hosts can reduce the negative fitness effects of parasite infection by avoiding contact with parasites or by resisting infection after contact. Because of their shared outcome, avoidance and resistance have been hypothesized to trade off with one another. Assuming these defences carry fitness costs, hosts are expected to have high levels of one defence or the other, but not both. Alternatively, avoidance and resistance may covary positively, if, for example, they complement one another or are genetically or mechanistically linked. Testing these hypotheses requires measuring avoidance and resistance independently, which is challenging because they are functionally linked. In this study, we separated avoidance and resistance of the host Caenorhabditis elegans against the bacterial parasite Serratia marcescens and tested for a correlation between them. We phenotyped a panel of 12 genetically divergent hosts using two distinct bacterial strains and multiple experimental contexts. We found no evidence of a correlation between avoidance and resistance. This result suggests that avoidance and resistance can covary independently. Moreover, we found strong strain specificity not only for resistance, but also for a measure of avoidance, motivating further research to examine the coevolutionary dynamics of avoidance.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144659299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defaunation erodes the diversity of rodent personality traits in fragmented forests.","authors":"Di Zeng, Thomas J Matthews, Rui Wang, Yuhao Zhao, Chuan Yan, Ping Ding, Xingfeng Si","doi":"10.1111/1365-2656.70105","DOIUrl":"https://doi.org/10.1111/1365-2656.70105","url":null,"abstract":"<p><p>Habitat fragmentation is a primary driver of biodiversity loss globally. One impact of habitat fragmentation is the resultant decline and loss of large and medium mammal populations (also known as defaunation). While the effects of habitat fragmentation and associated defaunation on species diversity are well documented, their impacts on intraspecific diversity are less studied. One understudied source of intraspecific diversity is the animal personality traits within populations. As individuals with contrasting personality traits may disproportionately contribute to ecosystem functions, losing diversity of personality traits could thus impair ecosystem functions, even if some individuals of the species still persist. However, it is still unclear how the diversity of animal personality traits changes in fragmented habitats with severe defaunation. Here, we conducted mammal surveys and comprehensive behavioural assessments of Niviventer confucianus (Chinese white-bellied rat)-the most abundant rodent-on 11 forested islands in Thousand Island Lake, China, a fragmented reservoir island system formed by dam construction. We used Bayesian structural equation modelling and a functional diversity framework considering intraspecific variation to disentangle the direct and indirect effects of habitat fragmentation and defaunation on the functional diversity of N. confucianus personality traits. We found that defaunation directly decreased the functional divergence of N. confucianus personality traits. Decreasing island area indirectly reduced the functional divergence of N. confucianus personality traits through intensifying defaunation. We also found that island area directly increased rodent abundance but simultaneously exerted an indirect negative effect via defaunation. However, we did not find an effect of rodent abundance on the functional divergence, nor any effects of habitat fragmentation and defaunation on the functional richness or functional evenness of N. confucianus personality traits. These results indicate that defaunation may play a key role in mediating the negative effects of habitat fragmentation on animal behavioural diversity. The defaunation-resultant declines of intraspecific behavioural diversity highlight the importance of measuring intraspecific diversity to better understand the ecological consequences of human-driven environmental changes on biodiversity.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144649507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal performance curves, activity and survival in a free-ranging ectotherm.","authors":"Kristoffer H Wild, John H Roe, Jonathan Curran, Phillip R Pearson, Lisa Schwanz, Arthur Georges, Stephen D Sarre","doi":"10.1111/1365-2656.70091","DOIUrl":"https://doi.org/10.1111/1365-2656.70091","url":null,"abstract":"<p><p>Temperature profoundly influences the distribution and diversity of ectotherms, yet in natural settings, interactions between environmental temperatures, behaviour, physiological function and the influence of these factors on individual survival remain poorly understood. In particular, it is unclear as to how trade-offs between these factors are optimised in wild, free-ranging species. We combined temperature-sensitive radio transmitters and accelerometers to measure in situ body temperatures and field-based thermal locomotor performance, estimating thermal optimum and maximum performance. This allowed us to quantify the effectiveness of thermoregulation in the wild and determine whether seasonal trade-offs in thermoregulatory behaviour shape thermal performance and influence survival in the Australian central bearded dragon (Pogona vitticeps). Lizards adjusted their behaviour to maintain optimal body temperatures, achieving greater thermoregulatory precision in spring and summer when environmental costs of thermoregulation were low, but reducing that precision in winter when costs were higher. Activity time and maximum locomotor performance were higher during seasons when thermoregulatory precision was high. Maximum locomotor performance in the field was a strong predictor of survival, regardless of sex, even though survival probabilities were higher in males than females. Higher locomotor performance was associated with increased mortality risk, but survival was not influenced by activity levels or thermoregulatory indices. These findings highlight the complex trade-offs that ectotherms must navigate to balance behavioural thermoregulation and survival. Our data demonstrate the important influence of seasonal and sex-specific variation on behaviour and fitness-related outcomes. Interpreting field-derived thermal performance curves alongside laboratory measures is crucial for distinguishing 'true' physiological capacity from the integrated ecological contexts that shape performance and fitness in nature. Such insights are vital for predicting how ectotherms may respond to future climate warming.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144642622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long-term population dynamics of western tent caterpillars: History, trends and causes of cycles.","authors":"Judith H Myers, Jenny S Cory","doi":"10.1111/1365-2656.70104","DOIUrl":"https://doi.org/10.1111/1365-2656.70104","url":null,"abstract":"<p><p>This is a story of unique long-term studies of the population ecology of a gregarious, cyclic forest insect, the western tent caterpillar (WTC), Malacosoma californicum pluviale. Early work by W.G. Wellington proposed that variation in the 'quality' and activity of larvae and moths influenced their population ecology. Our subsequent studies monitored six WTC populations over 29-50 years in south-western BC to determine the consistent characteristics of cyclic population dynamics. The six studied populations fluctuated more or less in synchrony with an eight to 11-year periodicity. Fecundity and tent size (an indication of early larval survival) increased with population increase and declined several years before the population peak. Fecundity and tent size were positively related to the population growth rate and declined before the population peak. Mortality from a baculovirus was high at peak densities, and the rate of population growth was negatively related to infection levels. Resistance to the virus varied among families and was higher following the epizootic at peak host density. Factors that might influence changes in fecundity were explored. Viral resistance was not related to moth fecundity, but sublethal effects as a result of surviving virus exposure could reduce fecundity. Declines in fecundity and tent size prior to the peak density could be a result of reduced foliage availability and quality from induced effects of larval feeding. Introduction and cropping experiments were unsuccessful at creating out-of-phase populations, and introduced insects appeared to carry the 'quality' of the source populations and declined synchronously with them. Warming temperatures influence the phenology of egg hatch and leaf development, but field experiments show that WTC larvae are resilient to this variation. No signal of an influence of a warming climate was apparent in long-term data. Longterm field observations indicate that changes in fecundity and viral infection can drive population cycles and inform the theory of cyclic dynamics. The early focus on variation among individuals was a prelude to the eco-evo thinking that has become accepted today but should include both genetic and phenotypic change as being relevant.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144636997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subtle stressors-Strong responses. Consistent negative effects of avian blood parasites on phenotypic and demographic traits across songbirds.","authors":"Marius Grabow, Sirkka Mang, Niels Blaum, Ralph Tiedemann, Viktoriia Radchuk, Stephanie Kramer-Schadt","doi":"10.1111/1365-2656.70106","DOIUrl":"https://doi.org/10.1111/1365-2656.70106","url":null,"abstract":"<p><p>Stressors that subtly yet persistently deplete energetic resources-such as heat, pollutants or parasites-are well studied in laboratory and clinical settings, where their physiological effects are often well understood, yet their influence on phenotypic and demographic traits in free-living populations remains critically understudied. A prominent example is pathogens and parasites that cause sublethal infections, often considered as relatively benign, particularly in species adapted to their presence. However, parasite-induced effects on phenotypic and demographic traits are often inconsistent, leaving researchers uncertain about their impact and whether they have meaningful fitness consequences. Here, we present a meta-analysis evaluating the effects of avian blood parasites (Plasmodium, Haemoproteus and Leucocytozoon), a widespread and cosmopolitan stressor, on songbird species. Through a systematic review of 2473 publications, we identified 35 studies spanning 51 species and extracted 172 relevant effect sizes assessing host condition, phenology, reproduction and survival. Our findings reveal consistent negative impacts: reductions in body condition, reproductive success and survival, along with delays in phenological events such as breeding. Furthermore, our findings revealed a critical research gap: despite the widespread study of avian blood parasites, only a limited number provide suitable effect sizes for assessing parasite impacts on demographic traits-let alone behavioural traits. This scarcity of data highlights the urgent need to understand pathogen-induced effects on animal behaviour and demography, especially in the face of accelerating global change. We advocate for an integrative approach, combining behavioural, phenotypic, and demographic traits, to uncover the cascading consequences of parasitic infections on wild populations.</p>","PeriodicalId":14934,"journal":{"name":"Journal of Animal Ecology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144618104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}