Rhodopsin of the Larval Mosquito

Abstract

Larvae of the mosquito Aedes aegypti have a cluster of four ocelli on each side of the head. The visual pigment of each ocellus of mosquitoes reared in darkness was characterized by microspectrophotometry, and found to be the same. Larval mosquito rhodopsin (λ_max = 515 nm) upon short irradiation bleaches to a stable photoequilibrium with metarhodopsin (λ_max = 480 nm). On long irradiation of glutaraldehyde-fixed tissues or in the presence of potassium borohydride, bleaching goes further, and potassium borohydride reduces the product, retinal, to retinol (vitamin A₁). In the presence of hydroxylamine, the rhodopsin bleaches rapidly, with conversion of the chromophore to retinaldehyde oxime (λ_max about 365 nm).