The Partitioning of Reproductive Energy between Ova and Protective Capsules in Marine Gastropods of the Genus Conus

The physical strength and energetic cost of egg capsules belonging to 10 species of Hawaiian Conus were determined in the laboratory. Capsular material was found to contain 5442 cal/g as opposed to 6238 cal/g for ova. Capsules accounted for up to 50% of total reproductive energy devoted to capsules and ova. Both the puncture resistance of capsules and the proportional energy allocation to capsules increased with increasing development time. Development time was found to be positively correlated with egg size. Strong capsules produced by species with large ova may have evolved as a result of selection for improved protection of embryos from predation and physical stress during a protracted period of development. The increasing allocation of reproductive energy to capsules as a function of egg size reflects the cost of producing stronger capsules.