Figure 2.

The dynamics of ant scanning movements. (a) Gaze direction (blue), body axis orientation (red) and bearing (black) relative to the release point with the true nest direction at 0° for a 2 s segment about 3 s after the ant had entered the platform. (b) Head orientation relative to the body longitudinal axis for the same sequence. (c) Time course of the angular velocity of the head relative to the body (green), the longitudinal body axis (red) and the gaze direction (blue) during the same sequence as shown in (a,b). Open arrows mark instances when head movements compensate for body rotations and black arrows mark instances when the head rotation is followed by body rotation. Sampling rate was 200 fps. (d) The relationship between the angular velocity of the body and the angular velocity of the head relative to the body for two example sequences (top row and bottom row). Left panels: scatter diagrams of head angular velocity over body angular velocity showing overall negative correlation. Centre panels: cross-correlation between head and body angular velocities, showing zero lag for the smallest negative correlation coefficient. Right panels: two-dimensional histograms of the centre section of the scatter plots on the left, showing high frequencies of head movements compensating for body rotations (maximal values along the diagonal) and high frequencies of head movements while the body is still (maximal values along vertical at zero body angular velocity).