Journal of Chemical Ecology, Vol. 12, No. 2, 1986 PHEROMONE BIOSYNTHESIS AND ROLE OF FUNCTIONAL GROUPS IN PHEROMONE SPECIFICITY DAVID MORSE and EDWARD MEIGHEN Department of Biochemistry, McGill University 3655 Drummond Street Montreal, P.Q. H3G 1Y6 (Received March 25, 1985; accepted August 1, 1985) Abstract--The sex attractants for many Lepidoptera are long-chain, mono- unsaturated acetate esters, alcohols, and aldehydes. In vivo metabolic studies and enzyme analysis in vitro have provided evidence that the aldehyde pher- omone of the eastern spruce budworm is synthesized de novo via an acetate ester precursor. Interconversion of the functional groups (ester, alcohol, al- dehyde) can explain differences in the pheromone blends used by closely related species. Key Words--Acetate esters, alcohols, aldehydes, fatty acid biosynthesis, insect pheromones, Lepidoptera, pheromone biosynthesis, spruce budworm. INTRODUCTION Although the pheromone complement of a given insect is typically a complex mixture of two or more components, the building blocks, or components, of lepidopteran pheromones are relatively simple molecules with marly structural similarities (Inscoe, 1982). Most pheromones of Lepidoptera are composed of a limited number of long-chain monounsaturated acetate esters, alcohols, or aldehydes, which vary with respect to chain length as well as position and con- figuration of the double bond. Consideration of the lepidopteran sex attractants, listed in a recent review (Inscoe, 1982) for almost 400 species, shows that the majority (77%) of species have pheromones with monounsaturated carbon chains between 10 and 16 car- bons in length. These compounds are displayed in a three-parameter diagram in Figure 1. The number of species attracted to a given compound is shown in the vertical dimension for each combination of chain length, double-bond po- 335 0098-0331/86/0200-0335505.00/0 9 1986 Plenum PublishingCorporation