HENDERSON, S.Y.: Adult nutrition on juvenile growth in Bugula pacifica

Bugula pacifica supplies nutrients to developing brooded larvae through a placenta-like attachment. Previous experiments of mine showed trends toward smaller larval size, slower growth, and longer time to first reproduction for juvenile colonies that came from nutritionally stressed adults when compared to larval and juvenile controls. Lab and field experiments performed in summer 2000 tested the influence of the adult environment on the success of developing larvae using a factorial design with two nutritional treatments (high and low). In the low food treatment colonies were maintained at ambient food levels, and in the high food treatment colonies received supplemental food twice daily. After two weeks, larvae collected from each adult treatment were allowed to metamorphose and placed in high and low food environments to examine the effect of adult nutrition on a suite of post-metamorphic characters. Juvenile colonies were observed for 26 days after larval settlement. Results suggest that the adult environment did not affect juvenile growth rate in high food conditions, but in low food conditions, juveniles from nutritionally stressed adults have slower growth and higher mortality. To examine the effect of adult nutrition on survival and growth under field conditions, newly settled larvae from the two adult treatments were allowed to grow on settlement plates and were transplanted after 3 days to the laboratory docks. Juvenile colonies were observed for 26 days after larval settlement. In the absence of competition, results indicate that juveniles from nutritionally stressed adults grow just as well as juveniles from fed adults.