Field studies of size‐dependent changes in waving display and other behavior in the fiddler crab,Uca pugilator(brachyura, ocypodidae)

Abstract

Field studies of 133 male Uca pugilator (4.5–20.0 mm carapace width) showed significant changes in waving and other behavior patterns as follows: (1) Wave frequency changed gradually from zero to 110–170 waves/5 min across the size continuum. (2) Wave rates stabilized at 10–12 mm carapace width. (3) Larger males spent about 50% of their above‐ground time performing actual waves. (4) Time spent feeding and time spent in the burrow decreased with age. In the case of feeding, there was a quantum drop to almost zero at the 12 mm carapace width size category. (5) The responses shown by females toward waving males of different sizes changed, so that there was a 70% increase in female attentiveness toward males in the larger size categories. Behavioral, morphological, and physiological data suggest that 10–12 mm carapace width may represent a transitional period in male fiddler crabs, which culminates in attaining full sexual maturity.