Effect of biological and anthropogenic sound on the orientation behavior of four species of brachyuran crabs

Abstract

The settlement phase of crustaceans is critical and can ultimately affect their population structure. Underwater sound has been proposed as one of the most important sensory cues used by these animals during this phase because it can provide direction and habitat quality information. Here, we evaluated the effect of different acoustic signals (biological and anthropogenic) on the orientation response of different stages (megalopae and juveniles) of 4 brachyuran crabs (Cyrtograpsus angulatus, C. altimanus, Neohelice granulata, Leptuca uruguayensis) from Mar Chiquita coastal lagoon in Argentina. A binary choice chamber system was used, and different sound sources (crustacean, fish and motorboat signals) selected from recordings of the lagoon soundscape were reproduced. C. angulatus megalopae and juveniles responded positively towards crustacean signals, while juveniles responded negatively towards fish sounds. N. granulata juveniles orientated negatively towards crustacean, motorboat and fish signals. C. altimanus and L. uruguayensis juveniles did not respond to fish signals. The results support the idea that invertebrates can discriminate among conspecific signals and highlight the role of sound on prey-predator relationships. The behavioral orientation response to the motorboat sound evidences a presumably negative effect of anthropogenic sound on the biological interactions of species. This information is important, given the urgent need to increase knowledge about coastal marine lagoons to enhance their protection, especially considering the role of the key species of crabs in this habitat.