Differentiation of cheliped asymmetry in the fiddler crab, Uca arcuata (De Haan, 1833)

Abstract

By rearing crabs from the first zoeal stage onward, transition of the cheliped condition in Uca arcuata was studied. All the first crabs had two small chelipeds. A crab stage having only one large cheliped on either left or right side (no cheliped on the other side) was preceded by a stage having two large chelipeds. Crabs bearing asymmetrical chelipeds appeared next and increase in number commensurate with decrease of crabs bearing only one large cheliped. This observation, as well as examination of samples collected from a natural population suggests that the differentiation process of handedness in Uca arcuata is the same as that demonstrated for Uca lactea by Yamaguchi (1977).