Meeting Abstract

110.6  Tuesday, Jan. 7 09:15  Quo vadis? Mechanical constraints on fish escape behavior ELLERBY, DJ*; HITCHCOCK, AC; Wellesley College dellerby@wellesley.edu

Successful predator evasion is essential to the fitness of many animals. Flexibility in escape behavior may be adaptive, as it reduces predictability and allows for behavioral modulation. High escape velocities and accelerations increase escape success, but biomechanical factors may constrain the behavioral range over which performance can be maximized. There may therefore be a trade-off between behavioral flexibility and mechanical performance. We have used fish escape responses to examine this trade-off, determining the full repertoire of escape behavior for individual bluegill sunfish and linking this to performance. Fish escapes involve an initial C-bend of the body axis, followed by variable steering movements. These generate thrust and establish the escape direction. Direction changes during the C-bend are relatively constrained, and the most frequent directions are associated with high performance. Individuals differ in escape behavior, magnifying overall variability. Steering in the subsequent stages of the escape also affects performance, with turns away from the stimulus reducing velocity. Our observations suggest that escape behavior is mechanically constrained, and that this imposes a performance cost for behavioral variation. This has important implications for understanding the scope and control of intra- and inter-individual variation in escape behavior and the associated costs and benefits.