Meeting Abstract
The aim of this study is to link the optomotor response of tobacco hawkmoths Manduca sexta to their lateral flight dynamics. Using a virtual-reality flight simulator, we exposed the moths to oscillating wide-field, sinusoidal gratings and simultaneously measured the flight response with a six-component force-moment balance. The moths were exposed to single-sine stimuli with temporal frequencies ranging from 1 to 12Hz. Apparent self-motion was provided about four axes: pure roll about the horizontal body axis x, pure yaw about the vertical body axis z, and coupled roll/yaw rotations about either the longitudinal body axis x’ or the dorsoventral body axis z’. We characterized the control mechanisms by estimating their time delays and comparing the magnitude and phase responses to those of common controllers. The responses to the four lateral perturbations consist of a coupled moment response, and to a first approximation depend upon feedback of both the angular position and angular rate of the stimulus. Additionally, we combined the measured responses to oscillations about the x and z axes to predict the measured responses to oscillations about the x’ and z’ axes. For most temporal frequencies, the linear superpositions closely match the measured responses to perturbations about the longitudinal and dorsoventral body axes. Although the measured optomotor responses are nonlinear inasmuch as they depend upon stimulus amplitude, it appears that these nonlinear responses to motion about different axes are effectively linearly superposed.
