Interspecific Communication in Fiddler Crabs: Preliminary Report of a Female Rejection Display Directed toward Courting Heterospecific ♂♂


Department of Biology, Box 3AF, New Mexico State University, Las Cruces, New Mexico 88003, U.S.A.

Department of Anthropology, University of Chicago, Chicago, Illinois 60637, U.S.A.


A newly described display is apparently used by female fiddler crabs (genus Uca) in interspecific communication. The display, termed repetitive-high-rise, is directed primarily toward courting heterospecific ♂♂, which approach or are likely to approach the ♀. We postulate that the display serves to indicate the ♀'s unavailability to these ♂♂ for mating. The ♂♂ respond appropriately by ceasing their approach toward displaying ♀♀. Both reproductively receptive and unreceptive ♀♀ were observed to perform this display. ♀♀ appeared to be able to discriminate, not only between conspecific ♂♂ and heterospecific ♂♂, but also among ♂♂ of heterospecific species. The possible significance for this ability is discussed.