Data from: Livestock abundance predicts vampire bat demography, immune profiles, and bacterial infection risk

Human activities create novel food resources that can alter wildlife–pathogen interactions. If resources amplify or dampen pathogen transmission likely depends on both host ecology and pathogen biology, but studies that measure responses to provisioning across both scales are rare. We tested these relationships with a four-year study of 369 common vampire bats across ten sites in Peru and Belize that differ in the abundance of livestock, an important anthropogenic food source. We quantified innate and adaptive immunity from bats and assessed infection with two common bacteria. We predicted abundant livestock could reduce starvation and foraging effort, allowing for greater investments in immunity. Bats from high-livestock sites had higher microbicidal activity and proportions of neutrophils but lower immunoglobulin G and proportions of lymphocytes, suggesting more investment in innate relative to adaptive immunity and either greater chronic stress or pathogen exposure. This relationship was most pronounced in reproductive bats, which were also more common in high-livestock sites, suggesting feedbacks between demographic correlates of provisioning and immunity. Infection with both Bartonella and hemoplasmas were correlated with similar immune profiles, and both pathogens tended to be less prevalent in high-livestock sites, although effects were weaker for hemoplasmas. These differing responses to provisioning might therefore reflect distinct transmission processes. Predicting how provisioning alters host–pathogen interactions requires considering how both within-host processes and transmission modes respond to resource shifts.人类活动可催生全新的食物资源，进而改变野生动物与病原体之间的相互作用。食物资源对病原体传播的增强或减弱效应，大概率同时取决于宿主生态学特征与病原体生物学特性，但同时覆盖宿主与病原体两个维度的资源补给响应相关研究却较为少见。我们针对秘鲁与伯利兹的10个家畜丰度存在差异的研究位点开展了为期四年的研究，共纳入369只普通吸血蝙蝠——家畜是该蝙蝠物种重要的人为食物来源。我们对采集的蝙蝠样本开展了固有免疫（innate immunity）与适应性免疫（adaptive immunity）的定量分析，并评估了其感染两种常见细菌的情况。我们提出假说：充足的家畜资源可降低蝙蝠的饥饿风险与觅食投入，使其能够在免疫功能上投入更多资源。来自高家畜丰度位点的蝙蝠，其杀菌活性（microbicidal activity）与中性粒细胞（neutrophils）比例更高，但免疫球蛋白G（immunoglobulin G）水平与淋巴细胞（lymphocytes）比例更低，这提示相较于适应性免疫，它们在固有免疫上的投入更多，同时也可能伴随更严重的慢性应激或更高的病原体暴露水平。该关联在繁殖期蝙蝠中表现最为显著，而繁殖期蝙蝠在高家畜丰度位点的占比也更高，这表明资源补给相关的种群统计学特征与免疫功能之间存在反馈调控作用。巴尔通体属（Bartonella）与血支原体（hemoplasmas）的感染均与相似的免疫特征谱相关，且两种病原体在高家畜丰度位点的流行率均更低——尽管血支原体的效应强度较弱。因此，蝙蝠对资源补给的不同响应，可能反映了不同的病原体传播过程。若要预测资源补给如何改变宿主-病原体之间的相互作用，需要同时考量宿主体内的免疫过程与病原体传播模式如何响应资源变动。