Figure 2.

Wingbeat amplitude during tethered flight. The direction of pattern movement alternated every 5 s from left to right and from right to left. a, Wingbeat amplitude (amp.) of the left (black line) and the right (gray line) wing. Pattern motion to the left is indicated by the gray boxes. b, Difference in wingbeat amplitude of left and right wings (wingbeat amplitude of left wing − wingbeat amplitude of right wing). The fly was trying to compensate for the visual stimulus. temp. freq., Temporal frequency.