Figure 3. Angular distributions and tracks of foragers on the orientation platform during intensity threshold experiments with 370 nm (a, b) and 440 nm (c, d). Only the results of the control tests and the last critical tests with which the ants' homeward orientations were lost were given for each stimulus. a) 370 nm control test, I = 1.1 × 1011 photons, P <0.0005; b) last critical test, I = 0.44 × 1010 photons, P> 0.05, not significant (n.s.); c) 440 nm control test, I = 1.1 × 1011 photons, P <0.01; d) last critical test, I = 1.1 × 1010 photons, P> 0.05, n.s. The triangle above each circle indicates the home angle. The dots around the circumference show the actual distribution of angles of foragers. Sample size = 30; h.a. = home angle; a = mean vector angle; r = mean vector length; u = critical values of the V test; d = deviation values around the 95% confidence interval. The dashed lines denote the 95% confidence interval around each sample mean.