Reproductive aspects and adaptive relative growth of the tropical crab Goniopsis cruentata

Abstract

The knowledge of reproductive traits is essential to the comprehension of the evolution of life history and population dynamics of a species. Here, we evaluate morphological maturity, relative growth, fecundity, relationship between size and fecundity, brood loss, and seasonal variation of brood size in the crab Goniopsis cruentata. Crabs were collected during a period of one year in a tropical mangrove, Northeast Brazil. Males matured at smaller sizes than females. Compared to other studies, this result indicates that there appears to be no pattern of sexual maturity between the sexes in this species, with both sexes maturing earlier or later. The relative growth of the gonopod length (males) and abdomen width and length (males and females) is clearly related to different sex roles, i.e., incubating eggs in females and maximizing the number of mates in males. Fecundity increased with female size and was similar to the fecundity of previous studies with the same species. Egg number of females incubating early-stage eggs was higher than those incubating late-stage eggs, indicating loss of eggs during embryogenesis. Fecundity of females occurring in the dry season was higher than that of females occurring in the rainy season, indicating seasonal variation of brood size.