Fig. 4. Results of oviposition tests. (A) Choice frequencies for seven colours versus the reference colour BG1 (see Fig.2A); 200 choices for each colour. The abscissa gives the attractiveness of a colour, and the equation for the underlying receptor interaction is given; Q_B, blue receptor quantum catch; Q_G, green receptor quantum catch; Q_R, red receptor quantum catch. The red line is the fitted model curve. For further explanation, see text and Appendix. (B) Choices for horizontally polarised light versus vertically polarised light of the same colour and intensity as a function of colour attractiveness. n is the number of choices in each experiment, all choice distributions differ significantly from chance (G-tests, P<0.001).