Retinal receptor types inAglais urticae andPieris brassicae (Lepidoptera), revealed by analysis of the electroretinogram obtained with Fourier interferometric stimulation (FIS)

Summary Electroretinograms obtained in the butterfliesAglais urticae andPieris brassicae by the procedure of Fourier interferometric stimulation (FIS) were used to construct spectral sensitivity curves. These curves, representing the combined responses of several receptor types, were approximated by summation of spectral sensitivity curves for individual pigments, and the presence of these pigments was corroborated by chromatic adaptation experiments. The results show that the retina in the compound eye ofAglais urticae contains 3 photopigments, with maximal absorption at ca. 360 nm, 460 nm and 530 nm, respectively (Fig. 5). The retina in the compound eye ofPieris brassicae has two subdivisions. In the dorsal region of the eye 3 photopigments were found, with maxima at ca. 360 nm, 450 nm and 560 nm (Fig. 8). In the medioventral region pigments with essentially the same maxima are present together with an additional, fourth long-wavelength component with effective maximal absorption at ca. 620 nm (Fig. 11). Its absorption curve is considerably narrower than would be expected for a rhodopsin with the same absorption maximum, and presumably results from the spectral combination of a photopigment and a photostable screening pigment.Abbreviations FIS Fourier interferometric stimulation - WLP White-light position - ERG Electroretinogram