Identification of cuticular hydrocarbons and the alkene precursor to the pheromone in hemolymph of the female gypsy moth, Lymantria dispar

Hydrocarbons were extracted from the surface of the cuticle and from the he molymph of adult female gypsy moths. GC and GC/MS analysis indicated that t he cuticular hydrocarbons with chain lengths >21 carbons were the same as t hose found ill the hemolymph, These consisted of mostly saturated straight chain hydrocarbons with heptacosane the major component. Methyl branched hy drocarbons were also identified including a series of tetramethylalkanes wi th chain lengths of 30, 32, and 34 carbons. In addition to those found on t he cuticle surface, the hemolymph contained the alkene pheromone precursor, 2-methyl-Z7-octadecene and two saturated analogues, 2-methyloctadecane and S-methyl-hexadecane. No evidence was obtained for the presence of the pher omone 2-methyl-7,8-epoxy-octadecane in the hemolymph, Pheromone gland extra cts indicated that small amounts (<1 ng) of the alkene precursor were also present in the gland. Relatively larger amounts of the alkene precursor wer e found in the hemolymph at the time when pheromone titers were higher on t he gland, The presence of the hydrocarbon pheromone precursor in the hemoly mph is discussed in relation to possible biosynthetic pathways for producin g the gypsy moth pheromone, Arch. Insect Biochem, Physiol, 43:108-115, 2000 , (C) 2000 Wiley-Liss, Inc.