Coral host specificity in settlement and metamorphosis of the date mussel Lithophaga lessepsiana (Vaillant, 1865)

The boring bivalve Lithophaga lessepsiana is found only in the coral Stylophora pistillata Esper, 1797, in the Gulf of Eilat, Red Sea. In laboratory experiments, L. lessepsiana larvae were found to choose S. pistillata as a substratum for settlement significantly more than all other coral substrata offered (p < 0.001). Furthermore, larvae were induced to metamorphose by tissue extracts of their known host significantly more than by extracts of other corals (p < 0.001). Larvae maintained in laboratory cultures retained the ability to metamorphose for 4 mth, with only very low incidence of spontaneous metamorphosis Our experimental results suggest that larval choice of substratum, and specific triggering of metamorphosis by the coral host, act together to form the species specific association between L. lessepsiana and S. pistillata.