Meeting Abstract

S11.8  Wednesday, Jan. 6  Go Reconfigure: How Fish Shift Shape Dynamically and Evolutionarily to Modulate Swim-mediated Behaviors LONG, J.H.*; ROOT, R.G.; PORTER, M.E.; LIEW, C.W.; Vassar College; Lafayette College; Lafayette College; Vassar College jolong@vassar.edu

Propulsion and maneuverability are driven by dynamic reconfigurations of body shape that are controlled, in part, by the mechanics of the musculoskeletal system and the evolutionary history of the lineage. To measure dynamic reconfigurations of the whole body during an undulatory swimming sequence, we have developed a method to compute shape reconfiguration errors and propulsive unsteadiness. An extreme example of transient body shape reconfiguration is turning. Using sharks, we examine turning reconfiguration and maneuvering performance as correlates of the shape of the static body, the biomechanical properties of the vertebral column, and shape of the vertebral column. To examine the evolutionary relationship between mechanical properties, body shape, propulsion, and behavior, we present a physics-based computer simulation of fish-like robots. These fish-like robots are self-propelled and autonomous, sensing light gradients and altering heading in response. We evolve these robots using a fitness function that rewards navigation and foraging success, both of which positively correlate with the spring stiffness of the tail. The spring stiffness is a mechanical property that varies inversely with the fineness ratio (lateral width: axial length) of the body. In sum, reconfigurations of body shape in physiological and evolutionary time could be mediated by mechanical properties and selection. This work was supported by NSF DBI-0442269 and IOS-0922605.