Meeting Abstract
As sea urchin larvae develop and grow post-fertilization, they produce a series of ciliated, skeleton supported “arms” that are used for feeding and swimming. Research has demonstrated that the size of these food-collecting structures trades off with the size of the primary food processing structure, the larval stomach. The magnitude and variability of the food treatment can also affect the magnitude of expression of these structures. Most studies of this phenomenon rear larvae in a single food treatment for the duration of the larval period, a condition which larvae are unlikely to experience in nature. As such, we understand little of how dynamic larval growth can be in response to changing food environments. We are conducting our experiments using larvae of the common sea urchin, Lytechinus variegatus, and will report how absolute and relative arm lengths, body lengths, and stomach volumes vary with respect to fluctuating food conditions. Preliminary observations made during data collection and analysis suggest that larvae fed high food initially and then switched to low food respond by lengthening their arms. We aim to discern the patterns of expression associated with the magnitude and plasticity of feeding and food-processing structures among larvae that are switched at specific time intervals from low to high food conditions and vice-versa. Our experiments will shed light on the existence and duration of distinct developmental windows for the expression of plasticity in this system.
