Chemical defense in developmental stages and adult of the sea starEchinaster(Othilia)brasiliensis

To date, evidence regarding the performance of secondary metabolites from larval stages of sea stars as an anti-predation defense relates only to a few species/specimens from a few geographic ranges. Unfortunately, this hinders a comprehensive global understanding of this inter-specific predator-prey interaction. Here, we present laboratory experimental evidence of chemical defense action in the early developmental stages and adults of the sea star Echinaster ( Othilia ) brasiliensis from Brazil against sympatric and allopatric invertebrate consumers. Blastulae, early and late brachiolarias of E . ( O .) brasiliensis were not consumed by the sympatric and allopatric crabs Mithraculus forceps . Blastulae were also avoided by the sympatric and allopatric individuals of the anemone Anemonia sargassensis , but not the larval stages. Extracts from embryos (blastula) and brachiolarias of E . ( O .) brasiliensis from one sampled population (João Fernandes beach) significantly inhibited the consumption by sympatric M. forceps , but not by allopatric crabs and A. sargassensi anemone. In this same site, extracts from adults E . ( O .) brasiliensis significantly inhibited the consumption by sympatric and allopatric specimens of the crab in a range of concentrations. Whereas equivalent extract concentrations of E . ( O .) brasiliensis from other population (Itaipu beach)inhibited the predation by allopatric M. forceps , while sympatric individuals of this crab avoided the only the higher level tested. Then, early stages and adult specimens of E . ( O .) brasiliensis can be chemically defended against consumers, but this action is quite variable, depending on the type (anemone or crab) and the origin of the consumer (sympatric or allopatric).