Meeting Abstract

P3.99  Wednesday, Jan. 6  Are the swimming kinematics of blind cavefish (Astyanax mexicanus) adapted for active flow-sensing? TAN, D*; PATTON, P; COOMBS, S; Bowling Green State University dstan@bgsu.edu

When visual cues are poor or unavailable, animals often use a form of active sensing in which they produce their own signal energy to probe various features of the environment (e.g. echolocation by bats). Blind cavefish exhibit a less-understood form of active sensing in which they use a kick and glide swimming style to generate a relatively stable, dipole-like flow signal during the glide phase of the swimming cycle. Nearby obstacles create distortions in the self-generated flow field, which can then be detected by the lateral line. In this study, we test the hypotheses that (a) blind cavefish have evolved behavioral specializations for active flow-sensing compared to their nearest sighted relatives (a morph of the same species) and (b) flow signal production is regulated by lateral line sensory feedback. We compared the swimming kinematics of blind and sighted morphs in response to a novel, dark environment – both (a) before and after a 24-hr familiarization period and (b) with and without a functional lateral line. After initial introduction, blind morphs with a functional lateral line (N=4) had shorter glide durations and higher glide velocities and frequencies than (a) blind morphs with inactivated lateral lines (N=3) and (b) sighted morphs with (N=4) or without (N=3) a functional lateral line. Inactivation of the lateral line had little effect on the glide parameters of sighted morphs. Glide parameters in both morphs were also unaffected by an additional period of familiarization. Our preliminary results suggest that blind cavefish have evolved active flow-sensing adaptations that include swimming kinematics to produce higher flow signal amplitudes and rates, as well as feedback control by the lateral line.