Meeting Abstract

27.1  Friday, Jan. 4  Assessing the potential for sexual conflict in the fiddler crab Uca princeps HANEY, B. R.*; POPE, D. S.; Trinity University; Trinity University brian.haney@trinity.edu

In fiddler crabs, the two most common mating tactics are burrow mating, in which males attract females into the male burrow by claw waving, and surface mating, in which males mate with a female on the surface near her burrow. Most fiddler crab species perform one or both of these tactics. There is also the much less common tactic of �directing,� in which a male, with his claw outstretched, attempts to back a female into a burrow for mating. We studied the fiddler crab Uca princeps in the upper Gulf of California; this population practices the directing tactic exclusively. If the male is successful in maneuvering the female into a burrow, he then is often challenged by neighboring males and must fight to defend the burrow and the female. Directing may be indicative of sexual conflict in this species; or it may point to �screening� by the female, in which female behavior serves as a filter for the highest quality mates. This study was undertaken to differentiate between these two alternatives by looking for signs that successful males are those that are able to best overcome female resistance (symptomatic of sexual conflict), or evidence that females mate with the highest quality males (suggesting screening behavior). We found that successful males did not have higher values of two quality indicator traits than unsuccessful males; however, they were relatively larger and heavier than the females they mated. The directing success of larger males and the unimportance of male quality in this mating system are more consistent with sexual conflict than screening. However, evidence of a cost to females inflicted by this male behavior is needed to definitively demonstrate sexual conflict.