Biochemistry of locusts. 3. Insectorubin: the redox pigment present in the integument and eyes of the desert locust (Schistocerca gregaria Forsk.), the African migratory locust (Locusta migratoria migratorioides R. & F.) and other insects

Abstract

The redox pigments of the eyes and integument of desert and African migratory locusts and of the eyes of Drosophila melanogaster (wild) and Ephestia kuhniella cannot be distinguished from each other. As the redox pigments reported in other insects also appear indistinguishable from this pigment, it is proposed that this widespread insect pigment be termed insectorubin. Insectorubin was isolated as a reddish-brown powder which quickly changes into an intractable dark-brown powder, reminiscent of melanin. It is extremely resistant to normal methods of chemical attack, but yielded 2 pyrrole derivates. These were not unequivocally identified but appeared to be N-methylpyrrole and hemopyrrole. Insectorubin is the pigment responsible for the color of the pink feces produced by starved locusts and of the pink patches in the subcut. tissue and integument of Locusta infected with Plistophora. Spectral data on the colors produced by a number of indole and pyrrole derivatives with Ehrlich''s diazo reagent are recorded.