Deterrent activities in the crude lipophilic fractions of Antarctic benthic organisms: chemical defences against keystone predators

摘要: Generalist predation constitutes a driving force for the evolution of chemical defences. In Antarctic benthos, asteroids and omnivore amphipods are keystone opportunistic predators. Sessile organisms therefore expected to develop defensive mechanisms mainly against such consumers. However, different habits characterizing each predator may promote variable responses in prey. Feeding-deterrence experiments were performed with circumpolar asteroid macropredator Odontaster validus evaluate presence defences within apolar lipophilic fraction invertebrates macroalgae. A total 51% extracts repellent, yielding proportion 17 defended species out 31 assessed. These results compared previous study which same fractions offered abundant circum-Antarctic amphipod Cheirimedon femoratus . Overall, less deterrence was reported towards (51%) than (80.8%), principally sponge algal extracts. amphipods, establish casual host–prey sedentary associations biosubstrata (preferentially sponges macroalgae), exert more localized pressure sea stars on certain sessile prey, would partly explain these results. The nutritional quality prey interact feeding deterrents, whose production is presumed be metabolically expensive. Although optimal defence theory posits that managed distributed as guarantee protection at lowest cost, we found only few deterrents most exposed and/or valuable body regions. Lipophilic metabolites broadly produced communities deter predators, although several combine traits. Keywords: invertebrates; algae; ecology; star ; defence. (Published: 7 April 2014) Citation: Polar Research 2014, 33 , 21624, http://dx.doi.org/10.3402/polar.v33.21624