A family of crown-of-thorns starfish spine-secreted proteins modify adult conspecific behavior

With growing interest in utilizing semiochemicals to control pest species, recent investigations have begun to consider semiochemicals to control outbreaks of crown-of-thorns starfish (CoTS; <i>Acanthaster</i> cf. <i>solaris</i>), a corallivore contributing to coral reef degradation. In this study, differential gene expression analysis of adult CoTS spines led to the identification of (1) numerous G-protein coupled receptor genes enriched at the reproductive stage, possibly reflecting enhanced sensitivity to semiochemicals and (2) genes encoding secreted proteins at the non-reproductive stage. We also demonstrated that these proteins belong to an uncharacterized family of secreted proteins that are unique to <i>Acanthaster</i> spp., being released into the surrounding water. A synthetic peptide mixture derived from this protein family demonstrated no toxicity yet did modify conspecific adult behavior, eliciting attraction. Based on this evidence, we suggest a pheromonal role beyond reproduction. The discovery of these provides a tool for future innovative semiochemical biocontrol in CoTS management strategies.