Spectral sensitivity of single photoreceptors in the compound eye of a tropical butterfly (Heliconius numata)

Summary The spectral sensitivity (wavelength region 330 to 650 nm) of single photoreceptor cells in the compound eye of the butterfly Heliconius numata (Lepidoptera) was studied by intracellular recording. The configuration and amplitude of the receptor potential was similar to that reported for other insect photoreceptor cells. Maximal sensitivity was found in one of the following wavelength regions: 390 to 410 nm, 450 to 470 nm and 530 to 550 nm. Side maxima of variable amplitude were found. The results suggest three photoreceptor types with different spectral sensitivity maxima.