The antennal system and cockroach evasive behavior. I. Roles for visual and mechanosensory cues in the response.

Cockroaches escape from predators by turning and then running. This behavior can be elicited when stimuli deflect one of the rostrally located and highly mobile antennae. We analyzed the behavior of cockroaches, under free-ranging conditions with videography or tethered in a motion tracking system, to determine (1) how antennal positional dynamics influence escape turning, and (2) if visual cues have any influence on antennal mediated escape. The spatial orientation of the long antennal flagellum at the time of tactile stimulation affected the direction of resultant escape turns. However, the sign of flagellar displacement caused by touch stimuli, whether it was deflected medially or laterally for example, did not affect the directionality of turns. Responsiveness to touch stimuli, and escape turn performance, were not altered by blocking vision. However, because cockroaches first orient an antenna toward stimuli entering the peripheral visual field, turn direction can be indirectly influenced by visual input. Finally, when vision was blocked, the run phase of escape responses displayed reduced average velocities and distances traveled. Our results suggest that tactile and visual influences are integrated with previously known wind-sensory mechanisms to achieve multisensory control of the full escape response.