Alfaro, M.E.*; Janovetz, J.; Blob, R.; Westneat, M.W.: Biting in Teleost Fishes

Biting is a distinct means of feeding in fishes in which upper and lower jaws forcibly grasp, tear, or cut the prey. Biting is a common mode of feeding in many groups of fishes, including parrotfishes, wrasses, cichlids, triggerfishes, surgeonfishes, damselfishes, and characins, yet the kinematics and motor patterns of this behavior have received relatively little attention compared to suction feeding. To quantify the muscular motor pattern of biting and to identify aspects of it that appear to be phylogenetically conserved, we recorded activity from the epaxialis, levator operculi, sternohyoideus, and subdivisions of the adductor mandibulae during the bite in species of parrotfishes, wrasses, and serrasalminae. In parrotfishes, significant species-level differences were found in the duration and timing of muscle activity, suggesting that the motor control of biting is evolutionarily plastic at relatively low phylogenetic levels. To determine if biting motor patterns differ significantly from suction feeding motor patterns, we used MANOVA and principal components analysis to compare EMGs of biting and suction-feeding taxa. The multivariate space occupied by biting and suction feeding is constrained by the motor control requirement of opening and then closing the jaws. However, biting in parrotfishes was significantly different than suction feeding in other teleosts, although there was a high degree of overlap among all feeding strikes. Many biters also showed little or no epaxialis activity, suggesting that, in contrast to suction feeding, cranial elevation is relatively unimportant in biting. ONR N000149910184 and NSF DEB- 9815614.