COORDINATION OF WING MOTION AND WALKING SUGGESTS COMMON CONTROL OF ZIGZAG MOTOR PROGRAM IN A MALE SILKWORM MOTH

The male silkworm moth, Bombyx mori, exhibits a zigzagging pattern as it walks upwind to pheromones. This species usually does not fly, but obvious wing-beating accompanies the pheromone-mediated walking. Males supported by a 'sled', after having their legs removed, also moved up wind in a pheromone plume along zigzagging tracks, indicating that win g-generated thrust and torque result in locomotory paths similar to th ose observed from walking moths. Using a high-speed video system we in vestigated the correlation between the wing movements and zigzag walki ng. The wing ipsilateral to the direction of the turn showed a greater degree of retraction with respect to the contralateral wing. The timi ng of the wing retraction pattern was synchronized with changes of dir ection in the walking track. Coordination of wing movements and walkin g pattern was not dependent on visual feedback or sensory feedback gen erated from neck movements associated with turning. The results presen ted here, taken together with our previous studies of descending inter neurons suggest that the coordination of wing movements with the walki ng pattern may result from the activity of a set of identified interne urons descending from the brain to the thoracic ganglia and/or may be coordinated by coupling of oscillating circuits for walking and wing b eating.