Hydroxylation of n-alkanes to secondary alcohols and their esterification in the grasshopper Melanoplus sanguinipes

Differences in cuticular lipid composition of the antennae of Helicoverpa zea, Heliothis virescens, and Manduca sexta

Analyses of the hexane washes of antennae, forelegs and whole bodies of Helicoverpa zea, Heliothis virescens, and Manduca sexta revealed notable differences in the components of the cuticular coatings of each species. Most striking were the differences between the cuticular coatings of male and female antennae of both H. zea and H. virescens. Novel esters of short-chain acids (C2-C4) and long-chain secondary alcohols (C25-C32) were identified in the hexane washes of the male antenna and forelegs of H. zea and H. virescens. These compounds were found in only small amounts or were completely absent on the female antennae of both species. In H. zea, butyrates of 7- and 8-pentacosanol and 8- and 9-heptacosanol were found, whereas, in the foreleg extracts of H. virescens, acetates and propionates were detected in addition to butyrates. While cholesterol is a major component of antennal washes (10-15%), only traces were found in the foreleg extracts. Although the composition of the cuticular coating of M. sexta differed greatly from that of the other two species, the extractable coatings of the antennae of male and female M. sexta were nearly identical.

Incorporation of oxygen-18 into secondary alcohols of grasshopper Melanoplus sanguinipes

Incorporation of 18-O2 and H2-18-O into the secondary alcohol moiety of wax esters in the grasshopper Melanoplus sanguinipes was determined by mass spectrometry. Results of this study show that oxygen-18 from 18-O2 was incorporated into the secondary alcohol, whereas no incorporation of oxygen-18 from H2-18-O was detected. The data suggest that the reaction, which hydroxylates n-alkanes at or near the center of the carbon chain, involves a mixed function oxidase type enzyme.