Colouring matters of the Aphididae. Part XXXV. Protodactynaphin

Abstract

Living specimens of the aphid, Dactynotus jaceae L. contain, among other glycosides, a new substance, protodactynaphin-jc-1, which is converted by enzymic or acidic hydrolysis into a mixture of xantho- and rhodo-dacty-naphins-jc-1. It is shown to be a simple glucoside of the dactynaphin aglucones previously discussed. It is presumed to exist in the living insect in the form of a xantho ⇌ rhodo equilibrium mixture, though only the isomer corresponding to the former (major) component has been isolated. Structural similarities between dactynaphins and other aphid pigments are discussed. Enzyme-containing extracts of D. jaceae convert protoaphin-fb into its aglucone rather than into xanthoaphin-fb.