Meeting Abstract

37.3  Monday, Jan. 5  Simultaneous correlation of odor-plume structure and behavior: II. Signal contrast at walking legs elicits steering in tracking blue crabs WEISSBURG, M.J*; DICKMAN, D.B.; PAGE, J.L; WEBSTER, D.R.; Georgia Inst. Technology; Georgia Inst. Technology; Georgia Inst. Technology; Georgia Inst. Technology marc.weissburg@biology.gatech.edu

Animals may use different sensor populations to regulate specific tasks during guidance. To directly discern the role of particular sensors in chemosensory searching, we used three-dimensional laser-induced fluorescence (3DLIF) to collect chemical concentration data simultaneously with movement in actively tracking blue crabs (Callinectes sapidus). Our data indicate that mechanosensory input, combined with input from chemosensors on walking legs, allows continued contact with the odor plume. Crab movement is adjusted to maintain a direct upstream heading (presumably using mechanosensation), with corrections toward the source modulated by chemical cues. Like moths, crabs are thus able to make numerous subtle corrections toward the source in the presence of frequent stimuli. The relative transverse bias of signals arriving at the legs mediates turning; animals receiving signals with directional bias in the transverse direction move in the direction of greatest signal intensity. Interestingly, crabs often face obliquely upstream so that legs on one side span the transverse direction and the legs on the other side are in their wake. Animals still execute appropriate turns when receiving biased signals across legs on one side, suggesting that CNS processing does not require bilateral (e.g. L-R) contrast to encode directional bias. Rather, the inputs from each sensor-bearing leg seem be preserved such that any contrast in the transverse direction provides steering information.