Fig. 3. Angular distribution of detour vectors in vector ants compared with that of zero-vector ants. Circles represent the first intersections (open circles, vector ants; filled symbols, zero-vector ants) between the trajectories of the ants and concentric circles (radii 1, 2, 3 and 4 m) centred on the ends of the barrier. Vector ants (open arrowheads) and zero-vector ants (filled arrowheads) do not differ in their mean angles and angular variations (P>0.05, Mardia–Watson–Wheeler test) at each of the circles. In both groups of ants, the mean angles do not deviate from the line (0°, arrow) connecting the end of the barrier with the fictive position of the nest relative to the barrier (
); angles are given clockwise from this direction. A comparison of the statistical details for vector ants and for zero-vector ants (values given in parentheses) at the 3 m circle for the left side of the barrier shows: mean angles 1.7° (359°); r-values 0.952 (0.941); number of ants 9 (13); 95 % confidence intervals 347.9–15.5° (348.9–13.1°); for the right side of the barrier, mean angles 5.4° (13.2°); r-values 0.969 (0.880); number of ants 10 (10); 95 % confidence intervals 355.1–15.7° (352.5–33.9°).
