Intra- and Interspecies Differences in Responses of Atlantic Sand (Uca Pugilator) and Atlantic Marsh (U. Pugnax ) Fiddler Crabs to Simulated Avian Predators

Abstract

ABSTRACT Responses of male and female Atlantic sand (Uca pugilator) and Atlantic marsh (U. pugnax) fiddler crabs to simulated bird predators were observed in South Carolina. When approached on the surface by a male and female sand fiddler crabs retreated at the same speed across the marsh surface. When reaching a burrow, male and female crabs initially descended similar distances; however, after each burrow was probed with the bill of an avian predator, females descended significantly further overall than did males. When chased, sand fiddler crabs initially retreated significantly farther into their burrows than did marsh fiddlers. However, after probing, both species had retreated similar distances overall. Sand fiddler crabs remained in their burrows three times longer than did marsh fiddler crabs. Our results suggest that crab antipredator behavior varies as a function of cost versus benefit, both within and across species.