Manta ray injury affects cleaner attraction, while cleaning behaviours reflect cleaner number

Abstract Cleaning mutualisms provide a useful framework for examining how cooperation and conflict are regulated, yet the extent to which client condition influences these dynamics remains unclear. We tested whether reef manta ray (Mobula alfredi) injury status is associated with cleaner engagement and behavioural dynamics at a cleaning station in the Philippines. Using video footage of 278 cleaning events from 96 individuals, mantas were classified as non-injured, having old injuries, or entangled (ongoing injuries). We found a distinction between the factors influencing cleaner attraction and those governing behavioural dynamics during cleaning. Injury category was significantly associated with the number of attending cleaner wrasse (Labroides dimidiatus); entangled mantas attracted significantly more cleaners than non-injured or previously injured individuals. By contrast, once an interaction was initiated, behavioural dynamics were more closely associated with local cleaner density than client condition. The probability of cleaner chases (reflecting intra-specific competition), the number of client jolts (aversive responses linked to conflict), and cleaning duration all increased significantly with cleaner number, whereas no additional association with injury category was detected. Because injury category itself predicted cleaner abundance, however, injury may remain indirectly relevant to these behavioural dynamics through its association with cleaner number. These findings suggest a pattern in which client condition establishes the scale of the interaction by attracting cleaners, and the resulting social environment and intra-specific competition are more closely associated with how the interaction unfolds. This highlights a fundamental distinction in mutualistic systems between cleaner attraction and the regulation of interaction dynamics.