Larval metamorphic competence in four species of Phestilla (Gastropoda; Opisthobranchia)

Abstract

Many marine invertebrates depend on their larvae for dispersal and to find the appropriate habitat for adult survival, yet their larval ecology remains poorly known. In this study we test the time required until metamorphic competence in the veliger larvae of four species of Phestilla nudibranch. Larvae of Phestilla melanobrachia are planktotrophic and had the highest percentage of metamorphosis in response to the prey coral Tubastraea aurea. Twelve days after hatching these veligers had approximately 30% metamorphosis in response to Tubastraea aurea polyps and to waterborne compounds released from T. aurea. Larvae of the facultative lecithotroph Phestilla sibogae had the highest rates of metamorphosis in response to Porites cylindrica after five days. However, P. sibogae also had approximately 50% metamorphosis in response to the non-prey coral Turbinaria reniformis. Phestilla minor had significantly more metamorphosis in response to Porites annae than to filtered seawater. Phestilla minor was the only species to have spontaneous metamorphosis in response to filtered seawater; 27% metamorphosis was observed after four days. The lecithotroph Phestilla sp. 2 had 80% metamorphosis in response to its host coral Goniopora fruticosa and to waterborne cues from G. fruticosa five days after hatching. This species also had approximately 40% metamorphosis in response to non-prey corals Porites cylindrica and Turbinaria reniformis. These different larval development times make Phestilla spp. an ideal group to study the ecological and evolutionary consequences of different life history strategies in marine invertebrates.