Mate preference in the neotropical freshwater crab Aegla longirostri (Decapoda: Anomura): does the size matter?

This study analyzed sexual selection in Aegla longirostri through one of the mechanisms that can alter species' evolution: mate choice. Y maze experiments were performed by placing a male or a receptive female (chooser) in the center of the maze; and two other individuals were placed each in a different corridor, according to the chooser: a receptive and an immature female, or two males that differed in size, respectively. The third corridor remained empty, and the choosers could walk among the branches of the maze. The results showed that only females spent more time in the corridors harboring a large male. Moreover, females had higher rates of movement in the corridors harboring males. Thus, female preference for larger males may be one factor that prompted the evolution of sexual dimorphism in this species.