July 11, 2005

Taking a Flying Jump

Ever wondered why you aren't able to swat a fly? The fly's secret in avoiding death in this way lies in its decision to jump rather than to fly out of the way. "This kind of low-power decision-making could be of interest to those building autonomously navigating robots", according to Gwyneth Card of the California Institute of Technology, who will be presenting her work on triggered escape response at the Society for Experimental Biology Annual Main Meeting in Barcelona, on Wednesday 13th July [session A7.15].

To investigate responses in Drosophila melanogaster, she performed experiments dropping black discs from different angles, on a collision course with the flies. Capturing the responses on video, she showed that flies escaped by means of jumping in a forward fashion and directly away from the object, in addition to using their wings. Her results suggest that signals in the brain transferred via the 'giant fibre pathway', initiate a "take-off" sequence, involving stretching of the legs and depression of the wings that can move the fly in a specific direction.

Previous studies did not detect directional jumping1, but observations were made in conjunction with non-directional stimuli such as switching lights on and off. Card's results imply that there could be a simple neural solution that "answers" questions within what is essentially a reflex arc.

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