Meeting Abstract

P2.83  Wednesday, Jan. 5  The role of adult density in larval settlement of Crepidula fornicata and C. plana CAHILL, Abigail E.; Stony Brook University acahill@life.bio.sunysb.edu

Many marine invertebrates have complex life cycles in which sedentary, benthic adults release planktonic larvae into the water column to develop for a period of hours to months before settling and metamorphosing into adults. This planktonic dispersal is a crucial factor in the connectivity of populations, species’ potential for range expansions or shifts in the face of global climate change, and their potential for spread following introduction to a new area. Many species in the calyptraeid gastropod genus Crepidula have planktotrophic larvae; two of these, C. fornicata and C. plana, live on the east coast of North America. C. fornicata lives in dense aggregations of multi-individual stacks as adults, while C. plana is rarer within sites and does not form large stacks. Larvae of both species use waterborne cues from adult conspecifics to induce settlement and metamorphosis. To determine how larval settlement in the two species differs in response to changing densities of conspecific adults, I conducted laboratory experiments using serial dilutions of adult-cue-infused water. Different threshold responses to concentration of adult cue may create species-specific feedback loops to enhance or inhibit the settlement of larvae. These in turn may result in different distributional changes in response to warming water temperatures, which may be important both in North America and in the spread of invasive populations of C. fornicata in Europe.