Ar-1550 COMMON FIDDLER CRAB, Uca pugilator or Uca panacea

No creature is as preoccupied with sex as fiddler crabs. Males sit at the edge of their burrows, continuously beckoning the females with their vastly larger claw enticing them to join them down below. On a warm day when the tide recedes, the “herd” leaves their holes and parades down to the water’s edge by the thousands to eat diatoms. They sound like rustling leaves in a fall wind, when moving through the marsh grass. While they may not replace the white mouse as a laboratory experimental animal, Uca pugilator runs a close second. They are used to study neuro-secretory hormone control of mechanisms regulating light adaptation. Removal of the eye stalks causes chromotophores to contract, and the crab lightens. Injections of extract made of eye stalks into destalked crabs causes darkening.