Mechanisms of socially facilitated feeding in Zebrafish (Danio rerio)

The social facilitation of feeding, where individuals increase their feeding behavior in the presence of conspecifics, is widely documented, but the underlying mechanisms remain unclear, particularly regarding passive versus active facilitation and the role of individual differences, such as sex and personality. We investigated how visual exposure to non-feeding conspecifics influenced feeding behavior in zebrafish (Danio rerio), examining food consumption and other feeding related behaviors, while also assessing individual variation in boldness and sociability. Zebrafish consumed significantly more food pellets and manipulated food differently when conspecifics were present, indicating that passive social facilitation due to the mere presence of conspecifics was sufficient to increase feeding behavior. Males exhibited stronger socially facilitated feeding responses, consuming more pellets, spitting pellets more frequently, and orienting food spitting away from stimulus fish, suggesting competitive motivations. Females showed more cautious feeding behavior, holding pellets in their mouths for longer. Contrary to predictions, neither boldness nor sociability predicted individual differences in feeding behavior or responses to social context. Our findings demonstrate that social facilitation due to a passive audience and sex-specific competitive strategies influence the feeding behaviors of zebrafish.