Fig. 1

Mate choice of the sws1 mutant. a Body-color preference of Actb–SLα:GFP males without (black, n = 8) or with (violet, n = 16) the sws1⁻¹⁰ mutation. The males were given a choice between females of the Actb–SLα:GFP and ci strains, and the ratio of courtship events toward the ci females was plotted. Each dot represents one male, and the graph reports the mean value. The error bars are the 95% confidence intervals. Regardless of the presence or absence of SWS1, the males significantly preferred Actb–SLα:GFP females, and the ratios were not statistically different between the WT and the mutant fish (P = 0.977, Student’s t-test). b Normalized spectra of the white LED light used for breeding (black) and the sunlight (orange) measured at every 1 nm using a C-7000 Spectromaster (Sekonic). The colored arrows at the bottom indicate the absorption maxima (λ_max) of the medaka cone opsins [45]: SWS1 (violet); SWS2a and SWS2b (blue); RH2a, RH2b, and RH2c (green); and LWSa and LWSb (red)