Preferences of planktotrophic larvae of the tropical serpulid Spirobranchus giganteus (Pallas) for exudates of corals from a Barbados reef

Abstract

The serpulid polychaete Spirobranchus giganteus (Pallas) is an obligate associate of live coral. On Barbados reefs it is known to occur more commonly on some coral species than on others. Planktonic presettlement larvae of S. giganteus have been found to respond positively to water-borne exudates of two corals commonly colonised by the worm and to be indifferent to exudates of two rarely colonised corals. In this study planktonic larvae of S. giganteus from the Barbados fringing reef were examined for preferences for six coral species not previously tested. Larvae were given a choice between a test coral, a reference coral ( Montastrea cavemosa Linnaeus) and a glass bead control. S. giganteus larvae are known to have no preference for M. cavemosa. Larvae showed a preference for Porites astreoides Lamarck and Millepora complanata Lamarck, two species of coral commonly colonised by S. giganteus, no preference for Siderastrea siderea (Ellis et Solander), Dichocoenia stokesii Edwards et Haime and Dendrogyra cylindrus Ehrenberg, three species that are rarely or never colonised and no preference for Agaricia agaricites (Linnaeus), a coral whose role as a habitat for S. giganteus is unknown. The possibility that preferences of planktonic larvae may influence their distribution at the time of settlement is discussed.