MEPS 472:169-183 (2013)  -  DOI: https://doi.org/10.3354/meps10055

ABSTRACT: In marine systems, water-borne chemical cues may induce anti-predator responses that influence not only performance and survival of the prey, but also population dynamics and species interaction. The early life stages of marine species with complex life-cycles settle into unpredictable habitats, and therefore may be expected to exploit reliable chemical cues emanating from both prey and predators in order to promote plastic responses to the local conditions. We compared the behavioural responses, survival and growth of early ontogenetic stages of Concholepas concholepas exposed to the risk of predation by natural predators that commonly co-occur with it in the intertidal: the crabs Homalaspis plana and Acanthocyclus hassleri and the asteroid Heliaster helianthus. Y-maze experiments indicated that C. concholepas use water-borne cues both to detect prey and deploy strong anti-predator behaviour. Our results indicate lower survival rates of small specimens of C. concholepas when they were maintained in the direct presence of predators rather than under control conditions. Similar results and growth inhibition were found with C. concholepas exposed to seawater in which the predators had been maintained. Quantification of feeding activity and shell thickness in response to predation risk indicated lower prey consumption and thicker shells when C. concholepas were exposed to crab odours compared to control conditions. Our results suggest that this behavioural receptiveness to water-borne cues may be responsible, in part, for the early plasticity of species with complex life-cycles such C. concholepas under natural conditions, facilitating predator avoidance and thus enhancing survival.

KEY WORDS: Escaping behaviour · Foraging · Growth · Survival · Water-borne cues · Risk‑sensitive