The effect of starvation on acquisition of competence and post-metamorphic performance in the marine prosobranch gastropod Crepidula fornicata (L.)

Abstract

The duration of the precompetent period of development determines the obligate dispersal period for larvae of many benthic marine invertebrate species. This study considers the extent to which the onset of metamorphic competence in the gastropod Crepidula fornicata (L.) is controlled by growth rate or the attainment of a critical, threshold size. Precompetent larvae of C. fornicata were starved in filtered seawater for up to 6 days at 25 °C and subsequently tested for competence by 5 h exposures to 20 mM excess K + in seawater. Control larvae were reared in excess phytoplankton suspension ( Isochrysis galbana, clone T-ISO) and tested for metamorphic competence concurrently with starved individuals. Even though larvae stopped growing (and in fact lost up to 37% of their initial ash-free dry weight) after being transferred to filtered seawater, many individuals became competent to metamorphose while being starved. These results suggest an allocation of limited energy stores to differentiation rather than to growth, and clearly indicate that the onset of metamorphic competence is not size-dependent and does not depend on growth for larvae of this species. Metamorphosed juveniles grew more slowly if they had been starved as larvae, indicating a link between larval nutritional experience and post-metamorphic performance.