Fig. 5.

Anti-tracking an aversive odor plume does not initially require wide-field motion vision. (A,C,E) Top: heading trajectories of all individuals in the presence of a uniform visual panorama (as compared with wide-field visual input in Fig. 1B,D,F) in continuous odor plumes of (A) water, (C) ACV and (E) 80% BA. Odor plume is indicated by a black arrowhead (0±10 deg). Flies began the trial at 90 deg (see Materials and methods). (B,D,F) Histogram of the time individual flies spent in 20 deg regions of the arena, indicated by black circles. Data are means (black line) ± s.e.m. (shaded gray region). (G–I) Percentage of total flies that occupy the plume (black line) or anti-plume (gray line) over the entire length of the trial in the presence of (G) water, (H) ACV and (I) BA. (J) Mean saccade amplitude and (K) frequency over the entire 25 s experiment with uniform (UNI) or high-contrast (HC) visual input. Asterisks indicate a significant difference compared with water in the same experiment (*P<0.05); hatch marks indicate a significant difference compared with the same odor in the high-contrast condition (paired t-test, ^#P<0.05). Error bars indicate ±s.e.m. (L) Vector strength of mean heading position over time in the presence of static high-contrast stripes or uniform visual input. Values closer to zero represent a wide spread in heading distribution, whereas values closer to one indicate a mean heading with a smaller variance. See Materials and methods for the equation used to calculate the r-statistic. (M) Percentage of flies that occupy the plume or anti-plume in the last second of the experiment. Asterisks indicate a significant difference compared with the corresponding odor plume or anti-plume under wide-field visual conditions (chi-square, *P<0.05).