Reproduction effort in the nudibranch Phestilla sibogae: calorimetric analysis of food and eggs

Abstract

Phestilla sibogae, a nudibranch living on corals of the genus Porites, is rarely found on the reef at Kaneohe Bay, Hawaii, although Porites compressa is a dominant coral there. This is probably due to massive predation on juveniles and adults. Such predation pressure would force this species to put high effort into reproduction. P. sibogae laid eggs amounting to up to 17% of their body weight each day. Based on a 100% conversion efficiency for ingested coral tissue, 51-78% of the calories each individual ate daily were channeled into egg production. Photosynthetic activity of zooxanthellae in the nudibranch's tissue suggests that the algae may provide some of the energy required by the animal's metabolism. -Author