Note
In this study, visual spectral sensitivity, based on microspectrophotometry and electrophysiological measurements of photoreceptor response, is directly compared to the behavioral spectral efficiency of luminescent countershading. Microspectrophotometric measurements on single photoreceptors revealed only a single visual pigment with peak absorbance at 495 nm in the blue-green region of the spectrum. The peak electrophysiological spectral sensitivity of dark-adapted eyes was centered at about 500 nm. The spectral efficiency of luminescent countershading showed a broad peak from 480 to 520 nm.