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Synopsis Wildlife health comparisons within and across populations and species are essential for population assessment and surveillance of emerging infectious diseases. Due to low costs and high informational yield, hematology is commonly used in the fields of ecoimmunology and disease ecology, yet consistency and proper reporting of methods within these fields are lacking. Previous investigations on various wildlife taxa have revealed noteworthy impacts of the vein used for blood collection on hematology measures. However, the impacts of venipuncture site on bats, a taxon of increasing interest in ecoimmunology and disease ecology, have not yet been tested. Here, we use a long-term study system in western Oklahoma to test the effect of venipuncture site on hematology parameters of the Mexican free-tailed bat (Tadarida brasiliensis) and cave myotis (Myotis velifer), two abundant and representative bat species from the families Molossidae and Vespertilionidae. Between September 2023 and October 2024, we collected paired peripheral blood from both the propatagial and intrafemoral veins in 25 individuals per species. We then quantified total red and white blood cells, reticulocyte counts, and leukocyte differentials and used generalized linear mixed models to compare parameters among venipuncture sites within and between bat species. Overall, venipuncture site had no effect on any hematology parameters; however, we revealed small differences in neutrophil and lymphocyte proportions between veins among the species. By contrast, we detected significant species-level differences in most cell measurements, which we propose could be explained by life-history strategy and phylogenetic differences. We encourage continued testing of additional venipuncture sites, and of the same venipuncture sites on different species, on hematology and other health metrics used in ecoimmunology and disease ecology. Lastly, we emphasize the importance of thorough method reporting in publications to enable transparent comparisons and accounting for even small sampling-based artifacts. All future efforts are especially important for bats to improve conservation monitoring, ecosystem services estimations, and their association with emerging infectious diseases. 

Synopsis Understanding wildlife immune responses is crucial for assessing disease risks, environmental stress effects, and conservation challenges. Traditional ecoimmunology approaches rely on targeted assays, which, while informative, often provide a fragmented and species-limited view of immune function. Proteomics offers a powerful alternative by enabling the high-throughput, system-wide quantification of immune-related proteins, providing a functional perspective on immunity that overcomes many limitations of conventional methods. However, proteomics remains underutilized in ecoimmunology despite its potential to enhance biomarker discovery, host–pathogen interaction studies, and environmental health assessments. This perspective highlights proteomics as a transformative tool for ecoimmunology, disease ecology, and conservation biology. We discuss its unique advantages over other -omics approaches, including its ability to capture realized immune function rather than inferred gene expression, its applicability to diverse wildlife taxa, and its potential for longitudinal immune monitoring of individuals using minimally invasive sampling. We also address key challenges, including limited genomic reference resources, sample constraints, reproducibility issues, and the need for standardized protocols. To overcome these barriers, we propose practical solutions, such as leveraging proteomes of closely related species for annotation and using their annotated genomes as search spaces for peptide mapping. Additionally, we highlight the importance of alternative quality control strategies and improved data-sharing practices to enhance the utility of proteomics in wildlife research. To fully integrate proteomics into ecoimmunology, we recommend expanding public reference databases for non-model species, refining field-adapted workflows, and fostering interdisciplinary collaboration between ecologists, immunologists, and bioinformaticians. By embracing these advancements, the field can leverage proteomics to bridge the gap between molecular mechanisms and ecological processes, ultimately improving our ability to monitor wildlife health, predict disease risks, and inform conservation strategies in the face of environmental change. 

Abstract The emergence of SARS-CoV-2 highlights a need for evidence-based strategies to monitor bat viruses. We performed a systematic review of coronavirus sampling (testing for RNA positivity) in bats globally. We identified 110 studies published between 2005 and 2020 that collectively reported positivity from 89,752 bat samples. We compiled 2,274 records of infection prevalence at the finest methodological, spatiotemporal and phylogenetic level of detail possible from public records into an open, static database named datacov, together with metadata on sampling and diagnostic methods. We found substantial heterogeneity in viral prevalence across studies, reflecting spatiotemporal variation in viral dynamics and methodological differences. Meta-analysis identified sample type and sampling design as the best predictors of prevalence, with virus detection maximized in rectal and faecal samples and by repeat sampling of the same site. Fewer than one in five studies collected and reported longitudinal data, and euthanasia did not improve virus detection. We show that bat sampling before the SARS-CoV-2 pandemic was concentrated in China, with research gaps in South Asia, the Americas and sub-Saharan Africa, and in subfamilies of phyllostomid bats. We propose that surveillance strategies should address these gaps to improve global health security and enable the origins of zoonotic coronaviruses to be identified. 

Abstract The ability of multiple bat species to host zoonotic pathogens without often showing disease has fostered a growing interest in bat immunology to discover the ways immune systems may differ between bats and other vertebrates. However, interspecific variation in immunological diversity among bats has only begun to be recognized. The order Chiroptera accounts for over 20% of all mammalian species and shows extreme diversity in a suite of correlated ecological traits, such that bats should not be expected to be immunologically homogenous. We review the ecological and evolutionary diversity of chiropteran hosts and highlight case studies emphasizing the range of immune strategies thus far observed across bat species, including responses to SARS‐CoV‐2. Next, we synthesize and propose hypotheses to explain this immunological diversity, focusing on pathogen exposure, biogeography, host energetics, and environmental stability. We then analyze immunology‐related citations across bat species to motivate discussions of key research priorities. Broad sampling is needed to remedy current biases, as only a fraction of bat species has been immunologically studied. Such work should integrate methodological advancements, in vitro and in vivo studies, and phylogenetic comparative methods to robustly test evolutionary hypotheses and understand the drivers and consequences of immunological diversity among bats. 

Abstract The prevalence and intensity of parasites in wild hosts varies across space and is a key determinant of infection risk in humans, domestic animals and threatened wildlife. Because the immune system serves as the primary barrier to infection, replication and transmission following exposure, we here consider the environmental drivers of immunity. Spatial variation in parasite pressure, abiotic and biotic conditions, and anthropogenic factors can all shape immunity across spatial scales. Identifying the most important spatial drivers of immunity could help pre‐empt infectious disease risks, especially in the context of how large‐scale factors such as urbanization affect defence by changing environmental conditions.We provide a synthesis of how to apply macroecological approaches to the study of ecoimmunology (i.e. macroimmunology). We first review spatial factors that could generate spatial variation in defence, highlighting the need for large‐scale studies that can differentiate competing environmental predictors of immunity and detailing contexts where this approach might be favoured over small‐scale experimental studies. We next conduct a systematic review of the literature to assess the frequency of spatial studies and to classify them according to taxa, immune measures, spatial replication and extent, and statistical methods.We review 210 ecoimmunology studies sampling multiple host populations. We show that whereas spatial approaches are relatively common, spatial replication is generally low and unlikely to provide sufficient environmental variation or power to differentiate competing spatial hypotheses. We also highlight statistical biases in macroimmunology, in that few studies characterize and account for spatial dependence statistically, potentially affecting inferences for the relationships between environmental conditions and immune defence.We use these findings to describe tools from geostatistics and spatial modelling that can improve inference about the associations between environmental and immunological variation. In particular, we emphasize exploratory tools that can guide spatial sampling and highlight the need for greater use of mixed‐effects models that account for spatial variability while also allowing researchers to account for both individual‐ and habitat‐level covariates.We finally discuss future research priorities for macroimmunology, including focusing on latitudinal gradients, range expansions and urbanization as being especially amenable to large‐scale spatial approaches. Methodologically, we highlight critical opportunities posed by assessing spatial variation in host tolerance, using metagenomics to quantify spatial variation in parasite pressure, coupling large‐scale field studies with small‐scale field experiments and longitudinal approaches, and applying statistical tools from macroecology and meta‐analysis to identify generalizable spatial patterns. Such work will facilitate scaling ecoimmunology from individual‐ to habitat‐level insights about the drivers of immune defence and help predict where environmental change may most alter infectious disease risk.