Comparative Analysis of Anti-predator Behaviour and Life History Traits of the Tadpoles Exposed to Predation Risk and Corticosterone

Anuran tadpoles show behavioural and morphological alterations in the presence of predatory cues (perceived predation risk). Recent studies suggested the possible role of stress hormone corticosterone (CORT) in anti-predator responses. We speculated that the anti-predator responses of prey tadpoles exposed to predation risk and CORT will be similar if they are mediated through CORT. In the present study, we compared behavioural and life history responses of Duttaphrynus melanostictus tadpoles exposed to (i) predatory tadpoles of Hoplobatrachus crassus , and (ii) two concentrations (1 and 10 µg/L) of CORT. The results revealed that exposure of the tadpoles to predation risk and CORT have similar effects on behaviour and life history traits. Tadpoles exposed to predation risk and CORT did not alter behaviour in response to alarm cues. Tadpoles exposed to predation risk and different concentrations of CORT delayed metamorphosis with a reduction in size. CORT influenced metamorphosis and size of the tadpoles in concentration dependent manner. These results suggest that the presence of non-lethal predators affects life history traits possibly through the stress hormone.