MILES, C.M.*; WAYNE, M.L.; University of Florida; University of Florida: Estimates of heritability for the trait of egg size in the serpulid polychaete Hydroides elegans

Some theories regarding the evolution of life history in marine invertebrates suggest selective changes in egg size as key transitional events. Egg size can only respond to selection if there is heritable variation for the trait. While phenotypic variation in egg size both among and within groups has often been documented in terrestrial and marine animals, heritability of this trait has only rarely been examined in marine invertebrates. The serpulid polychaete worm Hydroides elegans can be reared in captivity from egg through spawning adult, and has a relatively short generation time (approximately 4-6 weeks), making it amenable to quantitative genetic analysis. Two methods (regression of mid-offspring values on maternal values, and sib and half-sib analysis) were used to estimate narrow sense heritability for the trait of egg diameter in H. elegans. Preliminary data suggest that the heritability of the trait is around 0.20. The genetic correlation between egg diameter and the fitness-related trait of juvenile growth rate will also be addressed.