Figure 1.

The pattern of motion generated on the eye of a bee flying along a corridor or through apertures. The relative difference in the magnitude of optic flow (ω, red arrows), generated by points on the walls on each side of a corridor on the eyes of a bee flying with a different distance to each wall (d) but viewing them at the same angle (Θ, a). The relationship between the direction and magnitude of optic flow (red arrows) generated by the edges of an aperture on the eye of a bee flying on a perpendicular but off-centre trajectory (b) or diagonally towards the centre of an aperture (c). D, the perpendicular distance to the aperture; X, lateral distance to the point generating the optic flow.