Latent effects of larval food limitation on filtration rate, carbon assimilation and growth in juvenile gastropod Crepidula onyx

In this study we examined the latent effects of larval food limitation on the performance of juvenile Crepidula onyx under both laboratory and field conditions, and the possible mechanisms through which these latent effects were mediated. Larvae were reared at either high or low food concentrations before they were induced to metamorphose. Feeding larvae at a low food concentration reduced the size, total organic content and energy reserves of newly metamorphosed juveniles. Juvenile growth (measured as increases in shell length and total organic carbon content) and survival were then followed for 3 to 17 d. Under both laboratory and field conditions, we found that growth was compromised for the juveniles that developed from larvae fed at the low food concentration. However, feeding larvae at the low food concentration reduced juvenile survival only under laboratory conditions, not in the field. Thus, juvenile habitat conditions seem to have altered the latent effects of larval food limitation on juvenile survival. Our results also suggest that the filtration rate of juveniles developed from larvae fed at the low food concentration was significantly reduced. Follow-up experiments showed that the larval food concentration did not affect carbon assimilation efficiency of juveniles, and that the latent effects of limited larval food conditions did not simply reflect the consequence of reduced energy reserves or size at metamorphosis. Poor food-collecting performance of juveniles was at least partially responsible for the observed latent effects of larval food limitation on juvenile growth.