O tipo de substrato natural utilizado por caranguejos chama-maré do gênero Leptuca não influencia sua predação por Minuca rapax

Abstract

Fiddler crabs are semiterrestrial animals that occur in mangrove ecosystems along the Brazilian coast, and are suitable models for ecological and behavioral studies. From an anti-predator perspective, the type of substrate can influence the camouflage of prey and its detectability by visual predators, directly affecting their chances of survival. This study aimed to investigate the preference of Minuca rapax for two sympatric species of fiddler crabs (i.e. Leptuca leptodactyla and Leptuca cumulanta) on different substrates (i.e., mud and sand), in which they differ in body coloration and substrate use (i.e. L. leptodactyla inhabits sandy areas and has a light coloration, while L. cumulanta occurs in muddy substrates and has a dark coloration). In behavioral experiments on prey preference, individuals of M. rapax were simultaneously exposed to males of both Leptuca species, in which they were fixed to the substrate by a nylon line glued to the carapace and tied to a nail. Predator behavior was observed for 30 minutes in arenas delimited by acrylic plates, with the following actions recorded: (i) first approach, (ii) first attack, and (iii) first consumption. The results indicated no significant preference for any of the prey, regardless of the type of substrate. Although the species differed in coloration, factors such as movement, nutritional value, or the satiety state of the predator may have influenced the observed choices, but were not tested in this study.