Hidden fears: corticosterone-induced stress modifies subsequent risk assessment and antipredator behavior in a fossorial reptile

Abstract Antipredator behavior can depend on the internal state of an individual prey. Long-term chronic stress due to natural or human-induced environmental alterations can cause detrimental effects in animals, which may increase vulnerability to predators. Consequently, prey should modify their risk assessment and responses to predators. Here, we examined experimentally whether, and to what extent, the internal state of an animal affects risk-taking and antipredator behavior in a strictly fossorial amphisbaenian reptile Blanus cinereus . We increased circulating levels of glucorticoids of amphisbaenians using sustained in time non-invasive supplementations of corticosterone (CORT). In novel environments, but in the absence of predators, experimental CORT-supplemented individuals behaved more cautiously, moving less and travelling shorter distances compared to control individuals. However, in response to a simulated direct predation attack, CORT-supplemented individuals increased the intensity of their antipredator defensive behaviors and subsequently spent shorter times moving and searching on the soil surface before escaping by burrowing compared to control individuals. We found that they modified risk-taking and antipredator behaviors likely due to the increased physiological stress stemming from the CORT supplementation. Lowering the health status of amphisbaenians could increase their perception of risk level, which would require to modify their antipredator behavior accordingly. Examining the behavioral changes induced byincreased stress can help to identify the potential effects of human-related environmental degradation and whether animals may behaviorally compensate in modified habitats.