SEX-PHEROMONE BIOSYNTHESIS IN THE TORTRICID MOTH PLANOTORTRIX EXCESSANA (WALKER) INVOLVES CHAIN-SHORTENING OF PALMITOLEATE AND OLEATE

Biosynthesis of the sex pheromone components, (Z)-5 tetradecenyl aceta te (Z7-14:OAc) and (Z)-7-tetradecenyl acetate (Z7-14:OAc), was investi gated in the New Zealand tortricid moth Planotortrix excessana (Walker ) by fatty acid methyl ester (FAME) analysis of base-methanolyzed extr acts of lipids in the sex pheromone gland and through application of v arious labelled fatty acids. Analysis of the base-methanolyzed gland e xtracts revealed common FAMEs, including methyl oleate and methyl palm itoleate, as well as the FAMEs of the putative precursors, methyl (Z)- 5-tetradecenoate and methyl (Z)-7-tetradecenoate. Application of label led, saturated fatty acids, myristic, palmitic, and stearic did not re sult in any significant incorporation of label into either of the unsa turated pheromone components, although label was incorporated into tet radecyl acetate (14:OAc). In contrast, application of labelled oleic a cid resulted in incorporation of label into Z5-14:OAc but not into Z7- 14:OAc or into 14:OAc, whereas application of labelled palmitoleic aci d resulted in incorporation of label into Z7-14:OAc but not into Z5-14 :OAc or 14:OAc. These data support a route for biosynthesis of Z5-14:O Ac and Z7-14:OAc in this species by limited P-oxidation of the common fatty acyl moieties, respectively, oleate (involving two cycles of 2-c arbon chain-shortening) and palmitoleate (involving only one cycle of S-carbon chain-shortening), and apparently involving no desaturase (ot her than the common Delta 9) specific to sex pheromone biosynthesis. I nterestingly, P. excessana females biosynthesize the same component (Z 5-14:OAc) from an entirely different route from that of the related sp ecies Ctenopseustis obliquana (which biosynthesizes Z5-14:OAc by Delta 5-desaturation of myristate). Additionally, the pheromone biosynthesi s activating neuropeptide (PBAN) stimulates pheromone biosynthesis in this species. (C) 1998 Wiley-Liss, Inc.