When dangerous predators are ignored: antipredator responses in temporary-pond amphibians

Andrea Gazzola, Alessandro Balestrieri, Anna Sotta, Anita Giani, Daniele Seglie, Daniele Pellitteri-Rosa

Antipredator behaviour is recognised as a key factor of reintroduction success, yet it remains poorly considered in conservation practice. Despite their conservation relevance, little is known about antipredator behaviour in Pelobatidae tadpoles, among which the endangered Italian lineage of common spadefoot toad Pelobates fuscus has been the target of several captive breeding and reintroduction programs. We conducted four experiments to investigate the responses of spadefoot toad tadpoles to chemical cues associated with predation risk, focusing on ontogenetic variation, prior exposure, cue concentration, and predator identity. Contrary to expectations, tadpoles showed weak and inconsistent responses to odonate cues, despite dragonfly larvae eliciting strong antipredator responses in most previously tested anuran species. Prior exposure did not enhance responses, and variation in cue concentration produced only limited effects. Similarly, tadpoles did not modify activity level when exposed to alarm or disturbance cues. In contrast, when examining a set of eight different potential predators, clear antipredator responses emerged in response to those capable of exploiting temporary waterbodies. Overall, our results suggest that antipredator responses in P. fuscus tadpoles are shaped by the ecological conditions of the species’ preferred breeding sites, with reduced responsiveness to predators that are unlikely to occur in temporary ponds. Tadpole-naiveté towards predators associated with permanent aquatic habitats may explain the previously recorded declines in permanent fish-free ponds managed as conservation sites. These findings confirm that predator-prey interactions and antipredator behaviour should not be overlooked in conservation programs and highlight the importance of incorporating behavioural processes into conservation strategies.