Temporal patterns of Pederson shrimp (Ancylomenes pedersoni Chace 1958) cleaning interactions on Caribbean coral reefs

Dozens of marine species have been identified as cleaners and many of these co-occur and have considerable overlap in clientele. Understanding the temporal patterns and processes of these cleaning symbioses can provide insight into differential service provision between cleaner species and the ultimate and proximate causes structuring these interactions. Considerable progress has been made in understanding the ecology and behavior of cleaner fish, yet little basic ecological and behavioral data exist for cleaner shrimp. We deployed remote underwater video cameras on coral reefs in the Bay Islands, Honduras, to explore temporal variation of cleaning interactions at Pederson shrimp (Ancylomenes pedersoni) stations. We recorded more than 650 individual cleaning interactions in over 190 h of video. We find no significant temporal variation in cleaning station usage patterns across 17 families of reef fish. Our findings are in contrast to previously published data for interactions of Caribbean cleaner gobies, which co-occur at the sites we studied and overlap significantly in client pool with A. pedersoni but which are most active at dawn. These data suggest that the services provided by cleaner shrimp and cleaner gobies, rather than client identity, independently structure these interactions and drive the discordance in usage patterns between cleaner type. We propose two non-exclusive hypotheses to explain the differences in the temporal patterns of activity between cleaner gobies and A. pedersoni: (1) the proximate causes driving fish visitation rate (e.g., parasite removal or tactile stimulation) to goby and shrimp stations differ, and (2) each cleaner type targets different ectoparasites that differ temporally in their diel infestation rate on reef fish. Our study provides an important rationale for pursuing these questions and broadens our understanding of cleaning services on Caribbean coral reefs.