Meeting Abstract
The expression and evolution of phenotypic plasticity of feeding structures have been examined in sea urchin larvae. Larvae reared in low food conditions grow longer ciliated, skeleton-supported “arms” that are used for feeding, than genetically similar counterparts reared in high food conditions. Sea urchin larvae are also classic model organisms for the examination of developmental processes and mechanisms. Some research has begun to elucidate the molecular mechanisms underlying the plastic expression of larval arms during the initial hours to days of development. However, no research has explicitly examined morphological changes or trade-offs associated with nervous system structure and development between low and high fed larvae reared throughout the entirety of the larval period. These changes are to be expected, as nervous systems are notoriously plastic, forging and breaking connections among neurons and effectors in response to a host of internal and external factors. We are examining morphological differences in the nerves of the feeding arms and food-processing stomachs of larvae of the sea urchin, Lytechinus variegatus, using fluorescent staining and confocal microscopy. From these experiments, we anticipate finding differences in nervous system morphology and patterns of expression in these areas. The data we collect will elucidate the effects of plasticity in invertebrate nervous system development in response to external food resources. Further, these data will shed light on the patterns of nervous system development and growth that larvae may experience throughout the duration of the pre-metamorphic larval stage.
