Influence of male size and mating history on sperm content of ejaculates of the blue crab Callinectes sapidus

Laboratory experiments were used to determine the influence of male Callinectes sapidus (Rathburn) size (larger vs smaller than the size limit of the hard crab fishery in Chesapeake Bay, which is 127 mm carapace width) and mating history (recently mated males with depleted seminal stores vs those with fully recovered resources) on number of sperm transferred to females. Females mated by males with fully recovered seminal resources received significantly more sperm than those mated with males that had mated once previously, regardless of male size. No significant difference was found between the number of sperm delivered by small and large males with similar mating history. The sperm content of ejaculates from these laboratory experiments was compared to sperm received by females collected in the field. Only 11% of field-collected females received an amount of sperm as large as that delivered by the fully recovered males in our laboratory experiments. Of the field collected females, 77% received much less sperm, similar to or below the number delivered by depleted males in our laboratory experiments.