CONTROL OF THE SEX-PHEROMONE BIOSYNTHETIC-PATHWAY IN THAUMETOPOEA-PITYOCAMPA BY THE PHEROMONE BIOSYNTHESIS ACTIVATING NEUROPEPTIDE

This study shows that the pheromone biosynthesis activating neuropepti de (PBAN) is involved in the regulation of sex pheromone biosynthesis in Thaumetopoea pityocampa. rn vitro incubation of pheromone glands wi th PBAN resulted in a dose-dependent increase in pheromone titer. The formation of labeled pheromone from deuterated 11-hexadecynoic acid wa s stimulated in pheromone glands upon ill vitro incubation with PBAN. However, no differences were found between PBAN-treated glands and con trols in the amounts of labeled intermediates. In vivo experiments wit h deuterated (Z)-11-hexadecenoic acid and 11-hexadecynoic acid showed that 12,13-methylenehexadec-12-enoic acid inhibited both the delta-11 desaturation of (Z)-11-hexadecenoic acid and the Z-13 desaturation of 11-hexadecynoic acid. The amounts of natural pheromone produced by phe romone glands topically treated, in vivo, with 12,13-methylenehexadec- 12-enoic acid and further incubated, in vitro, with PBAN were similar to those found in glands that had not been administered the inhibitor. Topical application of (Z)-13-hexadecen-11-yn-1-ol to pheromone gland s irt vive resulted in the formation of the corresponding acetate. All these results indicate that PBAN controls pheromone biosynthesis in t he processionary moth by regulating a step involved in the transformat ion of the enyne acyl intermediate into the enynol.