Testing the threat-sensitive predator avoidance hypothesis: physiological responses and predator pressure in wild...

Area of Science:

• Ecology
• Animal Behavior
• Physiology

Background:

• Predation significantly impacts animal fitness, driving the evolution of antipredator strategies.
• Antipredator behaviors incur costs, necessitating accurate assessment of predation risk.
• Physiological stress responses may reflect an animal's perception of immediate threats.

Purpose of the Study:

• To investigate if European rabbits exhibit a threat-sensitive physiological stress response to varying predation pressures.
• To determine the primary drivers of stress hormone levels in wild rabbit populations.

Main Methods:

• Quantified fecal corticosterone metabolites (FCM) in 20 wild European rabbit populations.
• Assessed mammalian predator presence using track censuses.
• Accounted for confounding factors including breeding status, food availability, and rabbit density.

Main Results:

• Predator pressure was identified as the principal factor influencing glucocorticoid release.
• A positive correlation was observed between physiological stress response and the presence of mammalian carnivore predators.
• Factors like food availability and rabbit density had minimal impact on stress levels.

Conclusions:

• Wild European rabbits demonstrate an ability to assess predation risk.
• The study confirms a threat-sensitive physiological stress response in European rabbits.
• Predation risk is a key determinant of stress hormone levels in this species.