Light scattering in the eye of the blowfly chalky mutant: the effect on spectral sensitivity of photoreceptors R1-6.

In non-pigmented insect eyes, stray light causes the narrowing of the spectral sensitivity functions of the visual cells, and this effect is shown to be a sensitive tool for estimation of the stray light absorption by a photoreceptor. Spectral sensitivity functions of single cells of Calliphora chalky mutants were obtained in three sets of experiments with different contribution of stray light in total light absorption by a visual cell, and the relative parasitic absorption due to stray light appeared to be as high as 70% of total absorption even with a point light source. The effect of light scattering may be of some functional significance in non-pigmented parts of the wild type eyes as, for instance, in the dorsal rim area of the crickets.