Cleaning Mutualism – Client Preferences of Cleaner Wrasse Labroides dimidiatus at Monad Shoal

sina gil mandy waidelich

Reef fish as well as pelagic species are visiting cleaning stations to benefit from interactions with the cleaner wrasse Labroides dimidiatus foraging on ectoparasites and diseased tissue of their hosts. Despite the extensive literature on marine cleaning interactions, the answer to the question of what ecological factors determine the interactions between cleaners and their clients remains controversial. Investigated was the relationship between client species abundance, species specific traits (mobility, trophic group, social behaviour), client size as a reliable predictor of parasite loads and the duration of inspection by the cleaner wrasse L. dimidiatus. The study took place at Monad Shoal, a seamount in the Philippines famous for attracting pelagic thresher sharks (Alopias pelagicus). Data were acquired by SCUBA diving and the deployment of autonomous camera. The observation and analysis of 6856 cleaning interactions with a total duration of 151007 seconds between 233 species, identified within the scope of a visual census, and L. dimidiatus revealed that large, mobile, piscivore clients are preferred over small, resident, omnivore species. Furthermore the study provides evidence that pelagic thresher sharks represent an exceeding high quality foraging ground for L. dimidiatus.