Control of hatching in an estuarine terrestrial crab. I. Hatching of embryos detached from the female and emergence of mature larvae

Embryos of Sesarma haematocheir hatch simultaneously just prior to their release into water. Larval hatching occurs synchronously when the embryos are attached to a female. Clusters of embryos (200-2000 berries in each cluster) were detached from ovigerous females, and their hatching was compared with that of embryos attached to the females. Clusters of embryos that were detached from the female within 48-49.5 h of the projected time of larval release all hatched successfully, and swimming zoeas appeared. But embryos that had been detached from the female for longer periods did not hatch at all, though they were obviously alive. Detached eggs hatched later than eggs attached to the female, and their hatching was less synchronized. The female thus not only initiated hatching, but also enhances the synchrony of hatching. -from Author