Effects of spontaneous locomotion on the cricket's walking response to a wind stimulus

Tethered walking crickets often respond to single wind puffs (50 ms duratio n) directed from 45 degrees left or right to the abdominal cerci with a sho rt running bout of about 300 ms, followed by normal locomotion. To test for an effect of the current behavioral state on the running response, we appl ied wind stimuli when the insect attained a predefined translatorial and/or rotatorial velocity during spontaneous walking. The latency, duration, and velocity profile of the running bout always proved to be constant, represe nting a reflex-like all-or-nothing reaction, while the probability of this response was low after even brief standing and increased with the forward s peed of spontaneous walking at the moment of stimulation. In contrast, the current rotatorial speed did not affect the stimulus response.