Growth Phases and Differential Growth Between Sexes of Uca maracoani Latreille, 1802-1803 (Crustacea, Brachyura, Ocypodidae)

Abstract

Among crustacean decapods, fiddler crabs of the genus Uca are the most characteristic of the intertidal zones of tropical and subtropical estuaries. The present study determined the growth phases and the beginning of differential growth between the sexes, based on analyses of relative growth of Uca maracoani. Collections were made in the Jabaquara mangrove, located in Paraty, Rio de Janeiro, Brazil. Specimens were collected manually during low tide periods. In the laboratory, crabs were sexed and measured. We measured carapace width (CW), carapace length (CL), propodus length (PL; the right one for females and the major one for males), propodus height (PH), abdomen width (AW), and gonopod length (GL; for males). The beginning of differential growth between the sexes could be identified by the allometric technique. Males and females showed 3 distinct growth phases. Differential growth between sexes began when males reached 7 mm and females 9.2 mm CW. The growth pattern among different phases and the beginning of differential growth seemed to maintain a strict relationship with the ontogenetic changes, mainly those related to behavioral and reproductive aspects. This information is important for general biological knowledge of this species, mainly concerning aspects of its growth.