Abstract

Butterfly visual pigments have absorbance spectra that are very similar to spectra of vertebrate cone pigments. Template polynomials of absorbance as a function of the normalized frequency ratio were created for both rod and cone visual pigments. The spectral range of validity for these polynomials was extended beyond that of published nomograms by incorporating modern electrophysiological data. High-quality measurements of both the absorbance spectrum of visual pigment and the spectral sensitivity function of the very same receptor cells were obtained from the eyes of intact butterflies using optical methods. Partial bleaches measured with retinal densitometry were least-squares fit very well by the cone polynomial. Spectral sensitivity functions measured optophysiologically were least-squares fit very well to theoretical absorptance spectra that were computed using the cone polynomial. Fits based on the rod polynomial were very poor on the long-wavelength limb of the functions.

© 1987 Optical Society of America