Cuticular lipid composition of Heliothis virescens and Helicoverpa zea pupae

Abstract

The cuticular lipids of laboratory-reared tobacco budworms, Heliothis virescens (Fabricius), and corn earworms, Helicoverpa zea (Boddie), pupae were characterized. Quantities of cuticular lipid were greater for pupae in diapause than for non-diapausing pupae. Major cuticular lipids of H. virescens pupae were longchain n-alcohols (42%) and aldehydes (41%) with chain lengths of mainly C 26, C 28 and C 24 in decreasing order of abundance. Lesser amounts (2–5%) of wax esters and hydrocarbons were identified. The wax ester fraction was a complex mixture of C 32-C 52 components composed mainly of C 24-C 28 n-alcohol and saturated, monounsaturated and diunsaturated fatty acid (C 16-C 22) moieties. For H. zea, the major fractions were wax esters (38%), hydrocarbons (19%), n-alcohols (17%), diols (16%) and lesser amounts (2–5%) of aldehydes, acetate esters of alcohols and oxoalcohols. Triacontanyl hexadecanoate comprised 85% of the wax ester fraction. The H. zea alcohols, alcohol ester moieties and aldehydes consisted of a homologous series of C 32-C 52 compounds with the 30 carbon chain length as major constituents. The H. zea diols were C 30-C 36 even-chain n-alcohols with hydroxyl groups on carbon numbers 11, 12, 13, 14 or 15. Mass spectral analysis indicated the presence of unsaturation in the alkyl chain of the major diol components.