The breeding period of the fiddler crab, Uca lactea (Decapoda, Brachyura, Ocypodidae) in Japan

Ovary indices, percentage of ovigerous females and the presence of spermatophores in the vagina of females of Uca lactea, as well as the semilunar cycle of construction of the so-called "hood" by the males were examined. From these, the reproductive period of U. lactea, both in males and females, is deduced. This period starts in early June and continues to the end of August. Males have a semi-lunar cycle, but females have a lunar cycle and produce a clutch of eggs twice a year.