Predation Risk Experienced by Tadpoles Shapes Personalities Before but Not After Metamorphosis.

Abstract

Consistent inter-individual differences in behaviour, that is, personalities, can emerge as a result of inter-individual differences in ontogenetic experience, and predation risk is a potent one. As personalities develop over lifetime, however, they may also be broken by ontogenetic transitions of the individual. Here we first tested the hypothesis that consistent inter-individual differences in larval behaviour arise under predation challenge, and are entangled with differences in body size. We then tested the hypothesis that adult behavioural type is related to body size rather than to larval behavioural phenotype. To test these hypotheses, we performed a longitudinal study following the development of about 50 moor frogs, Rana arvalis. We manipulated their larval and current environment, and recorded their behaviours repeatedly, under control conditions, invertebrate predators' chemical cues or in live predator presence. Partially in line with our predictions, the ontogenetic experience of predator presence led to personality emergence in tadpoles, yet their behaviour was not explained by their body size. This pattern was lost over metamorphosis. According to predictions, pre-adult moor frog behaviour was affected by their body size-time to exit shelter was shorter in larger frogs-but neither by their behaviour as tadpoles nor by their larval environment, that is, tadpole predator-exposure experience. Our results show that individual behavioural tendencies can be well decoupled between prior and post metamorphosis, which adds to the growing empirical evidence supporting adaptive decoupling hypothesis.