Incorporation of labelled dietary n-alkanes into cuticular lipids of the grasshopper Melanoplus sanguinipes

Dietary hydrocarbons are incorporated into cuticular lipids of the grasshopper Melanoplus sanguinipes. Dietary secondary alcohols and ketones, however, are not incorporated into the cuticular lipids. In typical experiments from 8 to 28 per cent of the fed labeled n-alkanes are recovered in the cuticular lipids. Most of the radioactivity recovered from feeding the C₂₃ n-alkane and a significant amount from the C₂₅ was found as a secondary alcohol in the form of a wax ester. The C₂₉ and C₃₁ n-alkanes were recovered primarily unchanged as the n-alkane. Eighty-five per cent of injected acetate incorporated into the hydrocarbon fraction is in the branched hydrocarbons. These results show that the insect synthesizes its branched hydrocarbons, whereas a large part of the normal hydrocarbons can be dietary.