Dose–response curves for re-entrainment and corresponding action spectra. The dose–response curves (A) for so¹,so¹;gl^60j , andso¹;cry^b flies show the percentage of re-entrained flies for all wavelengths as a function of the irradiance. Forso¹;cry^b mutants both the flies with eye remnants (●) and completely eyeless flies (○) were tested. From left toright, the wavelengths for eyeless flies were 472, 486, 517, and 456 nm. Action spectra (B) were derived from these dose–response curves by determining the light intensities that were necessary to entrain 60% of the flies at each wavelength. The action spectrum for wild-type flies is derived from data byBlaschke et al. (1996).