67.7 Tuesday, Jan. 6 09:30 Kinematics of picking behavior in wrasses BALIGA, V.B.*; MEHTA, R.S.; Univ. of California, Santa Cruz; Univ. of California, Santa Cruz email@example.com
In fishes, cleaning is a mutualistic behavior wherein a species will remove and consume ectoparasites from other organisms. Previously, researchers have described the mouth movements of cleaner fishes as precisely and repetitively “picking” ectoparasites off clients. The term “picking” has also been described in the kinematic literature as “forceps-like” movements of the upper and lower jaws by cyprinodontiform taxa to selectively grasp specific food items from the water column. Whether the functional morphology of picking in cleaner fishes is similar to the kinematics of picking in cyprinodontiforms has yet to be systematically studied, and details of exactly how cleaner fishes capture their prey are lacking. Here, we filmed lateral views (at 1000 frames/second) of individuals from four species of wrasses (cleaners and non-cleaners) feeding on attached prey. Our kinematic analyses revealed that cleaners exhibit smaller magnitudes of lower jaw rotation, cranial rotation and peak gape values. Additionally, when we examined the correlation of timing variables, we found a higher degree of coordination (indicated by high correlations) in upper and lower jaw movements in the picking behaviors employed by cleaners when compared to the biting behaviors of non-cleaning taxa in our study. These results indicate that the kinematic basis for cleaning behavior lies in low-displacement, highly-coordinated movements of the jaws that enables cleaners to selectively acquire prey items that are attached to a substrate.