Meeting Abstract

101.8  Wednesday, Jan. 7  Role of multiple paternity in causing variation in larval growth rates in the gastropod Crepidula fornicata LE CAM, Sabrina; VIARD, Frederique; CAGNON, Mathilde ; PECHENIK, Jan A.*; Station Biologique de Roscoff ; Station Biologique de Roscoff ; Station Biologique de Roscoff ; Tufts University jan.pechenik@tufts.edu

The gastropod Crepidula fornicata has a long-lived larval stage that feeds on phytoplankton. During development, the larvae grow from about 400-450 �m to about 1000 �m in shell length, with the rate of growth varying markedly even among individuals from a single hatch from a single female. Some of that variation might be due to a familial component associated with multiple paternity, which is commonly observed in this species. To test that hypothesis, we reared the larvae from 6 females for about 1-2 weeks and then measured about 40 of the smallest (i.e., slowest-growing) individuals and about 40 of the largest (i.e., fastest-growing) individuals and preserved each larva separately for genetic analysis. We also preserved all of the conspecifics associated with each female. Paternity analyses based on microsatellite genotyping were then used to determine the father of larvae from each of the 2 categories. Among the 6 sampled females, most of the larvae were convincingly assigned to a male that was physically associated with the mother at the time of collection. The larvae sampled from each female had from 2-5 different fathers, most of which contributed to producing both fast and slow growing larvae. However, some fathers produced primarily fast-growing larvae within a brood. Our results suggest that multiple paternity in this species may increase the range of larval growth rates among siblings. To the extent that growth rates correlate with time to metamorphic competence, multiple paternity might contribute also to a larger range of planktonic periods and dispersal distances for sibling larvae.