Abstract

We tested the effects of body size, resident status, handedness, and claw originality on Uca rosea (Tweedie, 1937) male fights. We observed 67 pairs of combats between residents and intruders, recorded fighting duration and winner identity (resident/intruder, larger/smaller), identified handedness (right/left claw) and claw types (original/regenerated claw), and measured carapace width and major claw length. Larger/smaller males were determined based on major claw length instead of carapace width. Results showed that (1) body size and resident status jointly and (2) body size, resident status, handedness and claw types together, affected fighting success. Residents won more combats than intruders regardless of handedness. Original clawed residents won more combats than regenerated clawed intruders. Fighting duration was longer in same claw type (original-original and regenerated-regenerated) combats than in different claw type combats. Carapace width was more strongly correlated with original claw length than with regenerated claw length.