Meeting Abstract
26.2 Friday, Jan. 4 Multiple inputs mediate multiple outputs for flight control in Manduca sexta. HINTERWIRTH, Armin J*; DANIEL, Thomas L; University of Washington ahinterw@u.washington.edu
The astounding aerodynamic ability of insects hinges upon the integration of multiple sensory modalities and upon motor outputs that drive multiple actuators (wings and abdominal motions correlate with sensory input). Visual systems, for example, can detect image motion in order to gauge self-motion. Additionally, a wide array of mechanoreceptors can detect forces that result from disturbances in flight trajectory. Crepuscular moths, such as the hawkmoth Manduca sexta, accomplish low light vision by temporal pooling. The resulting delay substantially exceeds one wing-beat period and necessitates more rapid input from mechanoreceptive structures for course-correcting feedback. Such mechanoreceptive input was recently shown to originate in the antennae and is associated with gyroscopic forces (Sane et al. 2007). We have developed a tethered preparation in which we investigate the respective influences of the visual and mechanoreceptive systems in M. sexta in more detail. A moth is placed in an LED arena that can be mechanically rotated (after Sherman & Dickinson, 2003), thereby allowing independent control of each sensory modality. While visual and mechanical stimuli are presented, multiple output parameters, such as wing kinematics, power and steering muscle EMGs, and abdominal motion are recorded. Pure visual stimuli drive changes in wing motions, abdominal motions, and the electrical activity of the axillary muscles associated with wing control. Pure mechanical stimuli drive abdominal motions as well, though at lower gains than visually elicited motions, and with considerable variation among individuals. In addition, removal of antennae abolished the abdominal response to mechanical stimuli. These results suggest that flight control is a consequence of processing of multiple inputs to affect multiple actuators.
