Meeting Abstract
83.1 Tuesday, Jan. 6 Anterior to Posterior Wave of Buccal Expansion in Suction Feeding Fish is Critical for Optimizing Fluid Flow Velocity Profile BISHOP, K.L.*; WAINWRIGHT, P.C.; HOLZMAN, R.; University of California, Davis; University of California, Davis; University of California, Davis kvwbishop@ucdavis.edu
In fish that employ suction feeding, coordinating the timing of peak flow velocity with mouth opening is likely to be an important feature of prey capture success because this will allow the highest forces to be exerted on prey items when the jaws are fully extended and the flow field is at its largest. Although it has long been known that kinematics of buccal expansion in feeding fish are characterized by an anterior to posterior wave of expansion, this pattern has not been incorporated in most previous computational models of suction feeding. As a consequence, these models have failed to correctly predict the timing of peak flow velocity, which the empirical data currently available suggest should occur around the time of peak gape. In this study, we use a simple fluid dynamic model to demonstrate that the inclusion of an anterior to posterior wave of buccal expansion can correctly reproduce the empirically determined flow velocity profile, although only under very constrained conditions, whereas models that do not allow this wave of expansion inevitably predict peak velocity earlier in the strike, when the gape is less than half of its maximum. The conditions that are required to produce a realistic velocity profile are: 1) a relatively long time lag between mouth opening and expansion of the more posterior parts of the mouth, 2) a short anterior portion of the mouth relative to more posterior sections, and 3) a pattern of movement that begins slowly, then rapidly accelerates. Greater maximum velocities were generated in simulations without the anterior to posterior wave of expansion, suggesting a tradeoff between maximizing fluid speed and coordination of peak fluid speed with peak gape.
