Embryo brooding and its effect on feeding in the bivalve Gaimardia bahamondei Osorio & Arnaud, 1984

Gaimardia bahamondei is a small gonochoric bivalve which lives attached to subtidal algae. Females brood their embryos in the suprabranchial region of the pallial cavity, in close proximity to the gill filaments. We found no significant difference in clearance rate between males (non-brooders) and females (brooders), regardless of the numbers of embryos in the brood, suggesting that the presence of embryos does not interfere with particle capture by the brooding female. Embryos did not ingest microalgae, indicating that they do not compete with the female for food during incubation. These observations contrast with published data on other brooding bivalves in which particle retention by the adult is reduced during brooding, and the embryos may capture particles suspended in the pallial cavity. These differences among bivalve taxa in the effects of brooding on physiological processes in the female are attributable to distinct morphological adaptations of the gill for brooding.