Ontogenetic Patterns of Cleaner Fish Morphology
Nearly all cleaners in the genus Thalassoma clean predominately as juveniles. In a case study, I discovered that Thalassoma cleaner wrasses, as juveniles, possess jaws with low mobility and exhibit low bite forces compared to non-cleaner congeners (Baliga and Mehta, 2014). Upon reaching adulthood, however, morphological and functional differences between cleaners and non-cleaners begin to blur. The sizes at which I first found overlap between cleaner and non-cleaner species in feeding traits approximately correspond with the body lengths around which these species shift from juvenile to adult coloration patterns. Thus, a large suite of ontogenetic change accompanies the dietary shift in these species.