Sánchez-González Beatriz, Planillo Aimara, Navarro-Castilla Álvaro, Barja Isabel
Department of Biology, Zoology Unit, Universidad Autónoma de Madrid, Madrid, Spain.
Terrestrial Ecology Group, Department of Ecology, Universidad Autónoma de Madrid, Madrid, Spain.
Naturwissenschaften. 2018 Jan 31;105(1-2):16. doi: 10.1007/s00114-018-1540-6.
Predation is an unavoidable and dangerous fact in the lifetime of prey animals and some sign of the proximity of a predator may be enough to trigger a response in the prey. We investigated whether different degrees of predation risk by red foxes (Vulpes vulpes) evoke behavioural and physiological stress responses in wood mice (Apodemus sylvaticus). We examined the variation in mice responses due to individual factors (sex and reproductive status) and related them to the concentration of the volatile compounds from fox faeces over time. In our experiment, we introduced predation cues into four plots, each subjected to a different concentration treatment (0, 10, 50 and 100% concentration of fresh faeces of red fox), based on the following outline: initial odourless phase 0, phase1 in which predation treatment was renewed daily, and phase 2 in which we renewed the treatment only on the first day. Wood mice were live trapped during all three phases and the physiological response was measured non-invasively by analysing faecal corticosterone metabolites (FCM) in freshly collected faeces. Data were analysed by Generalized Linear Mixed Models. Overall, males were trapped less often than females, and reproductively active individuals from both sexes avoided traps more than non-reproductively active individuals, especially in medium- and high- concentration plots. Variations in FCM concentrations were explained by plot, the interaction between plot and treatment phase, and the interaction between the treatment phase and the reproductive status. During phase 1, we detected a significant rise in FCM levels that increased with predator faecal odour concentration. Additionally, reproductively active individuals showed a strong physiological response during both phases 1 and 2 in all plots, except the control plot. Our results indicated that wood mice are able to discriminate different degrees of predation risk, which allows them to trigger gradual changes in their behavioural and physiological stress responses.
在被捕食动物的一生中，捕食是一个不可避免且危险的现实，而捕食者接近的某些迹象可能足以引发被捕食者的反应。我们调查了赤狐（赤狐属）不同程度的捕食风险是否会在林姬鼠（小林姬鼠）中引发行为和生理应激反应。我们研究了由于个体因素（性别和繁殖状态）导致的小鼠反应差异，并将其与狐狸粪便中挥发性化合物随时间的浓度变化相关联。在我们的实验中，我们在四个地块引入了捕食线索，每个地块接受不同浓度处理（0、10、50和100%的赤狐新鲜粪便浓度），基于以下概述：初始无气味阶段0，第1阶段每天更新捕食处理，第2阶段仅在第一天更新处理。在所有三个阶段对林姬鼠进行活体诱捕，并通过分析新鲜收集粪便中的粪便皮质酮代谢物（FCM）以非侵入性方式测量生理反应。数据通过广义线性混合模型进行分析。总体而言，雄性被捕的频率低于雌性，并且来自两性的繁殖活跃个体比非繁殖活跃个体更频繁地避开陷阱，尤其是在中高浓度地块。FCM浓度的变化可以通过地块、地块与处理阶段之间的相互作用以及处理阶段与繁殖状态之间的相互作用来解释。在第1阶段，我们检测到FCM水平显著上升，且随着捕食者粪便气味浓度的增加而升高。此外，除对照地块外，繁殖活跃个体在所有地块的第1阶段和第2阶段均表现出强烈的生理反应。我们的结果表明，林姬鼠能够区分不同程度的捕食风险，这使它们能够引发行为和生理应激反应的逐渐变化。
