Larval release by adult fiddler crabs occurs during the ebbing tides, but its timing relative to the day-night and tidal amplitude cycles depends upon tidal form, e.g., shows phenotypical plasticity. Crabs (Uca thayeri) from Florida's East Coast are exposed to semidiurnal tides and release their larvae at night, whereas crabs from Florida's West Coast are exposed to mixed tides and release their larvae during the afternoon. The purpose of this study was to determine whether the larvae would hatch at other times, specifically those dictated by females from a different coast. To find out, clusters of eggs at similar stages of development, 24-72 h in advance of release, were reciprocally transferred between females from each location. Release of both the transferred and maternal larvae occurred synchronously, at the time dictated by the female's tidal regime. These results indicate that fiddler crab embryos can either advance or delay their hatching clock to match the temporal regime dictated by a brooding female.