Fig. 3.

Phonotaxis to simultaneous sources under laboratory conditions. Two synthetic sound sources broadcast synchronously (0-ms onset delay) to produce overlapping chirps (Inset). (A) Average walking trajectory of free-walking flies to sources separated by 90°. (i) Average response (n = 10 flies). (ii) Individual responses of a single representative fly. (B) Average walking response of flies to sources separated by 180°. (i) Average response (n = 9 flies). (ii) Individual responses of a single representative fly. Gray line within individual response plots (ii) indicate average responses. Square symbols (i) and horizontal/vertical projections from symbols indicate the mean and confidence intervals of the location of flies at 0.03-s intervals. Flies responded to simultaneous sources by directing phonotaxis to a phantom source location between broadcasting speakers (≈45° heading in 90° condition, ≈0° heading in 180° condition).