Meeting Abstract

5.4  Wednesday, Jan. 4  Response of Crepidula larvae to temperature as a function of geography and developmental mode: existence of local adaptation CAHILL, A.E.; Stony Brook University

Distributional changes are expected to become more common in the face of global climate change as species that cannot adapt to changing temperatures expand, contract, or shift their ranges. Marine invertebrate species with planktonic larvae are expected to show greater dispersal than those with direct development. In contrast, populations of directly developing species may show more potential for local adaptation due to low levels of gene flow from outside the population. Local adaptation to current water temperature may make a species more vulnerable to warming global temperatures. I use species in the genus Crepidula to examine the role of larval type in local adaptation to water temperature using a common-garden experiment. C. convexa is a direct developer, while C. fornicata and C. plana have a planktonic larval stage. C. convexa is known to have high levels of genetic structure compared to C. fornicata. However, it is unknown if such neutral genetic structure corresponds to ecologically relevant differentiation in growth and survival at different temperatures. To test for local adaptation to temperature in Crepidula, I studied the effects of temperature on growth and survival of larvae from populations from the northern, middle, and southern parts of the ranges of C. fornicata, C. plana, and C. convexa. I collected adults from all three species from populations along the east coast of the United States and raised them in common laboratory conditions in a factorial temperature*origin design at 12ºC, 20ºC, or 28ºC. There is no clear pattern of local adaptation in C. fornicata, but trends in survival in C. plana and C. convexa indicate potential local adaptation.