The development of social interactions in Corydoras aeneus larvae
Very young animals develop life skills as they mature, and for social animals this includes the acquisition of social abilities such as communication. Many animals exhibit changeable patterns of social behavior based on development, and social experience during the juvenile period can be vital for the development of necessary social behaviors in adulthood. We investigated the development of a distinctive tactile interaction behavior in Corydoras aeneus, the Bronze Cory catfish. Adults use this behavior to coordinate group activities during foraging and flight responses from predators, and the development of this behavior in larvae is of interest in investigating how communication and social behaviors develop as an individual matures, and which factors affect their development. We found that larvae respond to applied tactile stimulation with a flight response far less often as larvae matured, implying that larvae become less sensitive to tactile stimulation with age. Given that adults frequently interact with one another tactilely, this development is consistent with developing appropriate social behavior in adulthood. We also found that social exposure affects the development of the larval response to tactile interactions with conspecifics, and that isolation in the earliest larval stage leads to a greater likelihood of responding to a tactile interaction with a conspecific with a flight response. This suggests that social exposure is important for developing an appropriate response to tactile stimulation in social settings and underscores the particular importance of early life experiences in the development of sociality.