Genetic evidence of multiple paternity of broods in the intertidal crab Petrolisthes cinctipes

Abstract

Investigations of paternity among marine crustaceans are rare, but the few studies of brachyuran crabs that have been done to date suggest that most broods derive from single males. Here I use 2 hypervariable microsatellite loci to genotype a dozen brooded embryos from each of 10 gravid females of the porcelain crab Petrolisthes cinctipes (Anomura: Porcellanidae). Based on the number of non-maternal alleles detected among the offspring, at least 1 to 3 males must have fathered each of these broods, and most females were multiply mated. Using a Bayesian approach, I estimate the frequency of multiple mating to be roughly 92.5% in the Bodega Bay population, with a 95% confidence interval of 71 to 100% of females producing broods of multiple paternity.