MALE COURTSHIP CYCLES IN 3 SPECIES OF TROPICAL ILYOPLAX CRABS (DECAPODA, BRACHYURA, OCYPODIDAE)

The courtship behaviour and cycles of male courtship activity and colo uration of Ilyoplax orientalis, I. delsmani and I. gangetica were stud ied in the field in Malaysia and Thailand. Each species had a distinct ive chela waving or beckoning display. Depending on species, the cheli peds, carapaces, or both of waving males blanched to white in contrast to the cryptic colour of nonwaving males and females. All three of th ese tropical Ilyoplax exhibited semilunar cycles in male waving activi ty at the colony level. It was confirmed for I. orientalis that indivi dual males cycled each semilunar period between waving and non-waving phases and exhibited different behaviour toward females during these t wo behavioural phases.