Spectrophotometer measurements of average eyespot center brightness for each sex and seasonal form and hypothetical normalized absorbance spectra of B. anynana visual pigments. Brightness measurements (average of 10 individuals per curve) correspond to the Cu1 dorsal forewing eyespot white centre. Details of the measurement can be found in supplemental materials and methods of . Grey curves correspond to the absorbance spectra for the three visual pigments in B. anynana. Estimated λmax values for the long wavelength-absorbing pigment (560 nm) are from , and for the blue- (440 nm) and UV-absorbing pigments (350 nm), are based on intracellular recordings of other nymphalid butterflies [7, 8].