Reproduction of the vermetid gastropod Dendropoma maximum (Sowerby, 1825) in Moorea, French Polynesia

Abstract

Vermetidae are sessile molluscs with tubular shells cemented to the substrate. Although they are common inhabitants of coral reefs and rocky shores, little is known about the basic biology of most species. Dendropoma maximum is the largest vermetid species and is common across its Indo-Pacific range. Here we report on a study of reproductive and morphological traits in D. maximum from the lagoon around Moorea, French Polynesia. Both body length and diameter of shell aperture (generally the only visible part of the animal in the field) were good predictors of body weight and this relationship did not differ between males and females. Shell apertural diameter is therefore a good index of body size in D. maximum. The sex ratio became increasingly dominated by females with increasing body size, which is suggestive of protandric hermaphroditism. Probability of brooding, the number and size of brooded egg capsules, and the number of embryos per capsule were all positively related to female size. Females released veliger larvae that lived without additional food for up to 10 days, but were observed to feed when offered cultured phytoplankton on the final day. This is the first direct observation of feeding by larvae in this genus, and a planktotrophic larval stage has implications for potential dispersal in D. maximum.