Data Script from Co-variation between glucocorticoids, behaviour and immunity supports the pace-of-life syndrome hypothesis: an experimental approach

The biomedical literature has consistently highlighted that long-term elevation of glucocorticoids might impair immune functions. However, patterns are less clear in wild animals. Here, we re-explored the stress–immunity relationship considering the potential effects of behavioural profiles. Thirteen captive roe deer (Capreolus capreolus) were monitored over an eight-week period encompassing two capture events. We assessed how changes in baseline faecal cortisol metabolite (FCM) concentrations following a standardized capture protocol and an immune challenge using anti-rabies vaccination affected changes in 13 immune parameters of innate and adaptive immunity, and whether these changes in baseline FCM levels and immune parameters related to behavioural profiles. We found that individuals with increased baseline FCM levels also exhibited increased immunity and were characterized by more reactive behavioural profiles (low activity levels, docility to manipulation and neophilia). Our results suggest that the immunity of large mammals may be influenced by glucocorticoids, but also behavioural profiles, as it is predicted by the pace-of-life syndrome hypothesis. Our results highlight the need to consider co-variations between behaviour, immunity and glucocorticoids in order to improve our understanding of the among-individual variability in the stress–immunity relationships observed in wildlife, as they may be underpinned by different life-history strategies.

生物医学领域的既往研究已一致证实，糖皮质激素（glucocorticoids）长期升高可能会损伤免疫功能，但该效应在野生动物中的表现规律尚不明确。本研究结合行为表型的潜在调控作用，重新探讨了应激-免疫之间的关联。本研究对13只圈养狍（*Capreolus capreolus*）开展了为期8周的监测，期间共进行两次抓捕操作。我们分别评估了两个因素对免疫参数的影响：一是经标准化抓捕方案处理后，基线粪便皮质醇代谢物（faecal cortisol metabolite, FCM）浓度的变化；二是抗狂犬病疫苗接种引发的免疫挑战，二者如何影响固有免疫与适应性免疫共13项免疫参数的变化。同时，我们还探究了基线FCM水平与免疫参数的上述变化是否与行为表型存在关联。研究结果显示，基线FCM水平升高的个体，其免疫功能也更强，且表现出反应性更强的行为表型：活动水平偏低、易被操控的温顺特质，以及新物偏好（neophilia）。本研究结果表明，大型哺乳动物的免疫功能可能同时受糖皮质激素与行为表型的调控，这一发现与生命速率综合征假说（pace-of-life syndrome hypothesis）的预测相符。本研究结果凸显了一个研究重点：需纳入行为、免疫与糖皮质激素之间的协同变异，才能更深入地理解野生动物中观测到的应激-免疫关联的个体间差异——这类差异可能由不同的生活史策略所驱动。