MAIN PREDATORS OF CONCHOLEPAS CONCHOLEPAS (MOLLUSCA : GASTROPODA : MURICIDAE) AND PRELIM1NARY OBSERVATIONS ABOUT BEHAVIOURAL MECHANISMS OF ESCAPE AND DEFENSE

Abstract

Several specics of marine invertebrates and vertebrales prey upon thc muricid, Concholepas concholepas (tíruguicre). Our evidencc shows predation on intcrtidal and sub tidal populations of C. concholepas by; asteroids: Meyenaster gelatinosas and Heliaster helianthus: crustaceans: Homalaspis plana and Cáncer plebejus; birds: Latas dominicanas and Hacmatopus ater and mammals; Lutra felina and Otaria flavescens. C. concholepas shows five kinds of escape and/or defensivo responso when confrontcd with its predators; 1. Clamp down on the substratum (under mechanical or asteroids Chemical stimulus). 2. Clamp down (Ist. phase) and falling down (2nd. phase), under mechanical stimulus. 3. Spontancus falling down, under divers presence. 4. Rising and spinning of the shell, when confrontcd to M. gelatinosus. 5. Running escape, which is shown only by small intertidal individuáis (ca. < 40 mm.) when confrontcd to adult/A helianthus.