Fig. 5. Angular distribution of detour vectors associated with the rotated barrier. Detour vectors of zero-vector ants are superimposed and rotated in such a way that 0° marks the direction of the detour vector defined within an egocentric system of reference (hypothesis 3, green arrow). The arrow at 45° indicates the direction of the detour vector defined within an allocentric system of reference (hypothesis 1, blue arrow). The filled circles represent the first intersections of the trajectories of the ants with concentric circles (radii 1, 2, 3 and 4 m) centred on the end of the barrier (El/Er). The mean directions (arrowheads) do not deviate from 0°, but they are significantly different from 45°. Statistical details for the 3 m circle: mean angle 7.0°; r-value 0.926; number of ants 42; 95 % confidence limits 359.9–14.1°.
