Meeting Abstract

P2.54  Sunday, Jan. 5 15:30  Growth rate increases with temperature but decreases with initial size in Natica chemnitzi larvae MEYER, A.*; COLLIN, R.; Wesleyan University; Smithsonian Tropical Research Institute ammeyer@wesleyan.edu

Seasonal variation in environmental temperature influences egg size, hatching size, and growth rate in marine invertebrates. The effects of seasonal differences in hatching size on larval growth rates at environmentally relevant temperatures could have important effects on larval recruitment and survival. Two seasons (wet and dry) greatly affect the water temperature in the Bay of Panama. During the wet season, the water temperature is consistently 28 °C, but during the dry season, wind-driven upwelling brings colder water (23 °C) to the intertidal. Depending on when invertebrate larvae hatch, they will experience very different water temperatures. In this study, we investigate temperature-mediated differences in moon snail (Natica chemnitzi) larval growth and measure the plastic response of larvae produced in both seasons to temperatures typical of each season. To determine the effects of temperature and mother on larval growth, we raised larvae from ten females collected during the wet season. Hatchling larvae were marked with calcein and measured after 5 days growing at 28 and 23 °C. Larvae raised in 28 °C water were significantly larger at the end of the experiment and had grown significantly more than their siblings raised at 23 °C. There were significant differences in larval growth between females but no significant effect of the interaction between female and temperature on growth. One unexpected result was that hatchlings with large initial sizes grew less than those with small initial sizes. This experiment will be repeated in the dry season of 2014 to determine if the larvae produced in the dry season show the same patterns of temperature-mediated plasticity.