Quantifying hair cortisol has become popular in wildlife ecology for its practical advantages for evaluating health. Before hair cortisol levels can be reliably interpreted however, it is key to first understand the intrinsic factors explaining intra- and interspecific variation. Bats are an ecologically diverse group of mammals that allow studying such variation. Given that many bat species are threatened or have declining populations in parts of their range, non-invasive tools for monitoring colony health and identifying cryptic stressors are needed to efficiently direct conservation efforts. Here we describe intra- and interspecific sources of variation in hair cortisol levels in 18 Neotropical bat species from Mexico and Belize. We found that fecundity is an important ecological trait explaining interspecific variation in bat hair cortisol. Other ecological variables such as colony size, roost durability, and basal metabolic rate did not explain hair cortisol variation among species. At the individual level, females exhibited higher hair cortisol levels than males, and the effect of body mass varied among species. Overall, our findings help validate and accurately apply hair cortisol as a monitoring tool in free-ranging bats.

中文翻译：

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新热带蝙蝠毛皮质醇浓度的种间和种内变化

量化头发皮质醇因其在评估健康方面的实用优势而在野生动植物生态学中广受欢迎。但是，在可以可靠地解释头发中的皮质醇水平之前，首先必须了解解释种内和种间变异的内在因素。蝙蝠是一种生态多样性多样的哺乳动物，可以研究这种变异。鉴于许多蝙蝠物种在其范围的一部分中受到威胁或种群数量下降，因此需要使用非侵入性工具来监测菌落的健康状况并确定隐性应激源，以有效地指导保护工作。在这里，我们描述了来自墨西哥和伯利兹的18种新热带蝙蝠物种中毛发皮质醇水平变化的种内和种间来源。我们发现，繁殖力是解释蝙蝠毛皮质醇种间变异的重要生态特征。其他生态变量，例如菌落大小，栖息地持久性和基础代谢率，不能解释物种间毛发皮质醇的变化。在个体水平上，女性表现出比男性更高的头发皮质醇水平，并且体重的影响因物种而异。总体而言，我们的发现有助于验证并准确地将毛发皮质醇用作自由放养蝙蝠的监测工具。