Identification of Crustacean Sex Pheromones

Abstract

Odor and fragrances can carry information about an organism and have long been suggested as vital mechanisms that affect or control animal behavior. The use of such chemical signals is widespread in the aquatic environment, and crustaceans such as lobsters, shrimps, crabs, barnacles, and crayfish are known to utilize odor for predator–prey interactions, mating, establishing of dominance or social hierarchies as well as hatching of young and settlement of larvae. Nevertheless, the chemical identity of these behavior-modifying odors remains largely unknown. Here, we briefly review the literature on crustacean chemical signals and describe our approach to identify these using the example of the shore crab (Carcinus maenas) sex pheromones. We describe the principles of a bioassay-driven purification that is combined with a metabolomic approach where differences in the odor profiles of sexually active and inactive crabs are examined. Using such an integrated approach, we identified the female produced signal to be a nucleotide with its production being linked with the female molt (ecdysis). The pheromone enables males to detect the optimal time to mate just after the female molt with the timing of the reproductive event enabling crabs to use a simple, not species-specific, chemical as a sex pheromone. Based on our recent findings, we discuss the implications for future studies on crustacean chemical signaling.