Pelagic, feeding larvae of marine invertebrates invariably develop from small eggs that contain little yolk. In order to complete development, larvae must feed on suspended food particles in the surrounding seawater to supplement the reserves provided in the egg. In this project, the amount of material available for development to the initial feeding larval stage will be experimentally manipulated by altering the number of cells in the early embryo. The effect on initial larval morphology (size, shape, feeding structures) at the onset of feeding will be quantified. Subsequent larval growth and development will be evaluated under limiting and nonlimiting food conditions. This research project seeks to elucidate the important functional and developmental consequences of a change in the level of parental investment. The results apply to predictive models of life history ecology and evolution in marine invertebrates and foraging by pelagic suspension feeders.