KIM, TW; RISSANEN, R; REBEIRO, P; CHRISTY, JH; CHOE, JC; Seoul National University; University of Panama; Universidad Nacional de Mar del Plata; Smithsonian Tropical Research Institute; Seoul National University : Sexual differences in the affects of supplimental food on the semilunar reproductive rhythms of an intertidal crab

Fiddler crabs and many other intertidal animals have lunar or semilunar reproductive rhythms that follow the tidal amplitude cycles with these same periods. Female fiddler crabs typically release their larvae on days with large amplitude nocturnal tides which may reduce exposure of their vulnerable larvae to predation by diurnal planktivorous fish. Females mate about two weeks before their eggs hatch and males court most intensivly when most females are looking for mates. However, food availability and the time suitable for diurnal feeding also vary with the lunar cycle and the timing of reproduction by both sexes may reflect shared schedules of ingestion and allocation to reproduction. We explored this possibility by experimentally supplementing food to a mixed-sex population of fiddler crabs Uca terpsichores. The provision of additional food had no effect on the timing of sexual receptivity in females or in males but males courted more when they were better fed. This suggests that, female reproductive cycles are unaffected by natural cycles in food availability and that males expresses the same rhythm, presumably to maximize their opportunity to meet receptive females, but at an enhanced level when they are in better condition.