| We compared anatomical differences between sexes of P. samuelis, measuring the major cheliped and carapace lengths of hermit crabs, caught off the coasts of Southern California. Male chelipeds were significantly larger relative to their carapace lengths than female chelipeds. Average male cheliped:carapace ratios were 1.86 while average female cheliped:carapace ratios were 1.32. We suggest that intrasexual selection is the reason for dimorphism in this species. Behavioral gender differences were studied for responses to cue waters created from their own sex. We recorded hermit crabs exposed to cue treatment waters and analyzed four behaviors: withdrawn, head-extended, walking, and meral spread. In non-agonistic cue treatment waters, females were more likely than males to remain withdrawn in their shells. Males were more likely than females to display meral spread when sensing conspecific cues. Both sexes displayed no difference in the amount of time spent stationary with head-extended across all cue treatment waters. Both sexes tended to walk more in the presence of agonistic cue waters. |
