P3.115 Sunday, Jan. 6 The Morphology and Ontogeny of Cleaning Behavior in Labrid Fishes BALIGA, VB; Univ. of California, Santa Cruz email@example.com
In fishes, cleaning is a mutualistic service whereby one species consumes the ectoparasites or diseased tissues of another species. Cleaners may be categorized as obligate or facultative. The vast majority of fishes are facultative cleaners: they clean mainly as juveniles, switching to another diet as adults. Using Labrid fishes, a clade containing both obligate and facultative cleaners, this study seeks to identify whether there are specific morphological adaptations associated with cleaning behavior in juvenile fishes and how these traits may change over ontogeny. I measured 6 characters describing body shape in obligate cleaners, facultative cleaners, and their non-cleaning relatives across ontogeny. I find that obligate and facultative cleaners do not separate from their non-cleaning relatives in morphospace as juveniles or adults. However, when examining ontogenetic scaling patterns of body shape, I find that cleaners, both facultative and obligate, undergo a larger number of allometric changes over ontogeny than non-cleaners. Most notably, the elongation ratio, (a ratio of total length to maximum body depth) of facultative cleaner species as juveniles overlaps in range with that of obligate cleaners. As these facultative cleaner species grow, their body shape becomes less elongate and there is little overlap with obligate cleaners, which maintain the same elongate body shape across ontogeny. This result indicates that a decrease in body elongation, which results in a deeper, less fusiform body, coincides with the transition away from cleaning behavior in facultative species. Adults with deeper and larger bodies may no longer be able to dart continuously along the bodies of potential clients as they clean ectoparasites, forcing the adults to change their diets.