Escaping away from and towards a threat: the cockroach's strategy for staying alive.

The escape response of the cockroach is a well-studied example of sensorimotor behavior. Cockroaches respond to wind puffs, which may signal a predator attack, by making a swift turn followed by a forward acceleration. We have recently shown that their escape trajectories, measured relative to the position of the threatening stimulus, show preferred directions.1 Previous work has often distinguished between the most common type of escape turn, which begins as a rotation away from the stimulus, and the relatively rare turns initiated towards the stimulus. Here, we analyze these "away" and "towards" responses in light of our recent work on preferred escape trajectories (ETs). We find that the ETs of towards responses show a pattern of frequency distribution similar to that of away responses. The range of the bodyturn angles of towards responses, however, is much smaller than that of away responses, being <30 degrees in most cases, which approximately corresponds to the angular distance between ET peaks. This suggests that cockroaches minimize their turn when making a towards response, which could represent an effective anti-predator behavior that allows cockroaches to reach one of the preferred ETs within a relatively short time.