Figure 5

Tortuosity along the path. Index of path tortuosity at different distances away from the feeder (M ± sem) for ants from the control group (in black) and from the Rotation 16° condition (in grey) that displayed no U-turn before searching in front of the landmark. The tortuosity index corresponds to the averaged absolute angle (in radians) between the directions of successive chunks of 20-cm line segments connecting points on the path. A circle of 20 cm radius was placed at the starting point of the digitised path, and where the circle intersected the path defined the first segment. The circle was then placed at the end of segment 1 to define segment 2, etc.