Figure 4.

The precision of the dung beetle celestial compass in the presence and absence of the sun. The orientation error of the dung beetle celestial compass was determined by letting beetles roll out twice from the centre to the edge of the arena under different experimental conditions: with a full view of the sky (sun–sun, white bars), with the sun hidden from view (shade–shade, grey bars) or with the sun hidden from view only during the second roll (sun–shade, white/grey bars). The absolute angular difference between the two paths determines the orientation error. The orientation error in each condition was determined for different elevations of the sun: 75–78° (high elevations), 45–60° (medium elevations) and 15–30° (low elevations). In all experimental conditions, the orientation error at high elevations of the sun is significantly larger than that at medium or low solar elevations. Numbers in text and figure show mean ± s.e.m.