“…Thus it is not surprising that rhodopsin levels are reduced in insects suffering from vitamin A deficiency (Goldsmith et al, 1964;Brammer & White, 1969;Boschek & Hamdorf, 1976;Harris et al, 1977;Huber et al, 1990). More interesting is the observation that the apoprotein, opsin, is also severely reduced in insect photoreceptors by chromophore depletion (Paulsen & Schwemer, 1983;deCouet & Tanimura, 1987;Sapp et al, 1991a;Huber et al, 1994). In Drosophila, opsin is reduced to 1% of normal levels (Ozaki et al, 1993).…”