Meeting Abstract

S1.5  Sunday, Jan. 4  Biomechanical constraints on sensory acquisition in weakly electric fish MACIVER, Malcolm A; SHIRGAONKAR, Anup A; PATANKAR, Neelesh A*; Northwestern University; Northwestern University; Northwestern University; Northwestern University maciver@northwestern.edu

The knifefish Apteronotus albifrons hunts for small water insects at night using a self-generated electric field to perceive its world. Using this unique sensory adaptation, the fish senses prey that are near its body with a detection volume that approximates a cylinder that has a length ten times its radius, similar to the fishs elongated body plan. If the fish swims straight, then the back portion of the actively generated detection volume is scanning fluid already scanned by the front portion, but the energy expended to overcome drag is minimized. If it swims with the body pitched, then the rate of volume scanned for prey is increased, but the energy needed to overcome body drag is also increased. We examine the compromise the fish makes between minimizing drag and maximizing scan rate. We use computational fluid dynamics simulations to assess the impact of changes in body pitch angle on drag, and how the thrust from the ribbon fin propulsor changes with pitch angle. These mechanical studies are combined with high-fidelity computational neuroscience simulations to assess the shape and size of the prey detection volume and how body angle changes the scan volume rate. We find that the observed body pitch angle of 30 degrees during prey search behavior results in 35% higher volume scan rate while doubling the body drag, and that increasing the body pitch angle decreases the forward thrust available with typically observed fin deformation kinematics. The combination of neural and mechanical modeling allows us to show how the conflicting demands of biomechanics and information acquisition are negotiated in a core behavior.