Does predation risk, through moon phase and predator cues, modulate food intake, antipredatory and physiological responses in wood mice (Apodemus sylvaticus)?

Predation influences the ecology and behaviour of prey species and it is well known that the risk of predation affects prey's decision making. We investigated whether predation risk through moon phase and exposure to the faecal odour of a natural predator, the red fox Vulpes vulpes, affect feeding behaviour and physiological response in wood mice (Apodemus sylvaticus). Antipredatory response was studied by live trapping under new and full moon in odourless control areas and areas experimentally manipulated with red fox fresh faeces. Food intake by individuals was determined as the amount of bait remaining in each trap and the physiological response was measured non-invasively analysing faecal corticosterone metabolites (FCM). Traps treated with faeces of red fox were the most avoided, and this avoidance was more significant during full moon. Food intake by wood mice varied according to the moon phase being significantly lower under full moon nights. We found sex, breeding condition and weight of individuals explaining the variation found in FCM concentrations, but no changes in FCM levels due to moon phase or exposure to red fox faeces were detected. These results indicate that wood mice avoid red fox faecal odour and this antipredatory response as well as feeding behaviour are significantly influenced by moon phase. However, no physiological response was found due to predation risk suggesting that wood mice do not take these predation cues enough reliable to experience physiological changes.