Social overtures in Corydoradinae catfish mitigate the effects of acute stress

Stress from a variety of environmental factors has negative effects on individuals across species. In social species, stress may be exacerbated by social isolation and mitigated by social overtures, where individuals communicate with groupmates to fully reap the benefits of social grouping and cope with negative effects of environmental stress. We evaluated the effects of stress on pair coordination and engagement with a foraging task in Osteogaster aeneus , a gregarious catfish that communicates via tactile interactions. We netted pairs of fish from a social housing tank (a known stressor) and placed them in an unfamiliar tank for 1 hour, after which pairs performed a foraging task. We quantified stress via respiration rate (counting opercular movements) and frequency of stress-associated stereotyped behaviors, and propose this combination as a viable method for measuring both short and long-term stress. In the context of ecologically crucial tasks like foraging, this method informs how organisms cope with stress that comes with changing and/or unfamiliar environments. In our study, we found that respiration rate decreased over time and activity levels increased over time, and that a positive association emerged between stereotyped stress behaviors and social interactions, indicating that more stressed individuals initiate more social overtures. In the context of foraging, we found that rates of social overtures, and not the extent of the stress response, was associated with an individual’s willingness to forage in pairs. We conclude that social overtures may mitigate the effects of stress, leading to better foraging outcomes.