Colouring matters of the Aphididae. Part XXXII. Rhodoaphin

Abstract

Re-investigation of the pigments of Hormaphis (Hamamelisters) species shows that rhodoaphin-be is a dihydroxyerythroaphin, structurally analogous to dihydroxyerythroaphin-fb but stereochemically belonging to the tt series. This follows both from spectroscopic considerations, and its epimerisation to dihydroxyerythroaphin-fb on mild treatment with acid and is consistent with its behaviour on catalytic hydrogenolysis. Rhodoaphin is the first derivative of erythroaphin-tt to be obtained from natural sources. Its precursor, heteroaphin, which occurs in the living insect is consistent, spectroscopically, with being a simple rhodoaphin glycoside but has not been examined in detail. The triglyceride content of H. betulina is similar to that of other aphids. Myristate is the major component together with smaller amounts of palmitate and laurate.