The polychaete Cirriformia punctata is chemically defended against generalist coral reef predators

Abstract

The Caribbean cirratulid polychaete, Cirriformia punctata (Grube, 1856), is bright orange and burrows just below the surface of fine carbonate sand with only its filamentous tentacles and gills exposed to potential predators. In addition to its conspicuous coloration, C. punctata lacks obvious structural and morphological defenses. We hypothesized that C. punctata protects itself from predation using secondary metabolites as a chemical defense. Feeding bioassays were performed using whole worms to determine palatability against two generalist coral reef predators: the bluehead wrasse, Thalassoma bifasciatum, and the brown anemone, Aiptasia sp. Additionally, assays were conducted with hermit crabs of the genus Paguristes, but with limited success. In all assays, C. punctata was unpalatable to consumers. The tentacles and body of the worm were separately assayed using T. bifasciatum to determine whether the defensive mechanism was differentially allocated to body regions that are differently exposed to potential predators. Both the tentacles and body of C. punctata were unpalatable to T. bifasciatum, indicating no specific allocation of defenses. Crude organic extracts of whole C. punctata were unpalatable to T. bifasciatum, confirming that the worm defense is chemical rather than morphological. Chemical defenses of Cirriformia spp. appear to be generally effective against taxonomically diverse potential consumers.