Fig. 4. Distance between the animal and the arena centre, and turning angles at various experimental conditions. (A) Probability histograms and medians (dotted white lines) of the distributions obtained for flies responding to six different arena velocities. Means ± s.e.m. (B) Mean distance of the flying animal from the arena centre plotted against the fly's horizontal (forward) velocity (bin width, 0.1 m s^–1). Linear regression fit is plotted in red (y=0.016x+35.8, R²=0.88, N=13 horizontal velocity bins, P<0.001). (C) Total turning angle within a flight saccade (grey) and between two saccades (open) shown as a function of arena velocity. (D) Ratio of total turning angle during saccadic flight style and smooth turning between two subsequent saccades. Data show a minimum contribution of saccades to turning angle at 500° s^–1 arena velocity. SMT, time between two flight saccades; SAT, duration of a saccade. Means ± s.d., N=131 flies.