Meeting Abstract

4.5  Wednesday, Jan. 4  Maternal provisioning in echinoids: the role of egg constituents during pre-feeding larval development MCALISTER, J/S*; MORAN, A/L; Clemson University; Clemson University jmcalis@clemson.edu

Marine invertebrates with feeding larvae utilize maternally-provisioned material (protein, lipid, and carbohydrate) in the egg for morphogenesis and metabolism during early pre-feeding larval development. All eggs are not provisioned equally, however; there is tremendous variation among species, populations, and even individuals in egg size, composition, and energy. This variation suggests that differences in egg size, egg composition, and total egg energy may be associated with differences in the morphogenesis and metabolism of pre-feeding larvae. To determine the role of egg constituents during morphogenesis and early larval development, we investigated changes in biochemical composition, respiration rate, and morphology during pre-feeding larval development of echinoid ‘geminate’ species pairs from tropical America. Our data show that in geminate pairs, species from the low-productivity waters of the Western Atlantic (WA) that have larger eggs than their Eastern Pacific (EP) geminates also have eggs that are comparatively lipid-rich and protein-poor, suggesting that the large eggs of WA species are not simply scaled-up versions of the smaller EP eggs. We also reared larvae from WA and EP species of Diadema, Echinometra, and Eucidaris, without food, collected samples from successive developmental stages for biochemical analysis, and simultaneously measured O₂ consumption as an index of metabolic energy expenditures. We will use these data to assess the fate of maternally-provisioned egg constituents during larval growth to better understand how larval feeding environment and other selective factors affect the evolution of life histories.