HORMONAL-CONTROL OF SEX-PHEROMONE BIOSYNTHESIS IN DROSOPHILA-MELANOGASTER

Production of cuticular hydrocarbons including the female sex pheromon e cis,cis-7,11 heptacosadiene, was compared in intact and decapitated Drosophila melanogaster. Wild-type adults decapitated just after emerg ence showed very long-chain cuticular hydrocarbons (31-35 carbons) 3 d ays later, which are characteristic of young adults. Moreover among lo ng-chain hydrocarbons (23-29 carbons) of decapitated females the sex p heromone level showed a marked decrease accompanied by an increase in monoenes. The quantitative effect strongly depended on the age of deca pitation, being maximal when decapitation occurred within the first ho ur after emergence. Feeding had little influence on pheromone biosynth esis. A cephalic factor-yet to be characterized-seemed to exert the ma in control. Application of methoprene, a juvenile hormone (JH) analog, resulted in a decrease in very long-chain hydrocarbons in decapitated females but did not enhance the synthesis of sex pheromones. The anal ysis of mutants deficient in JH production confirmed the role of JH in the cuticular hydrocarbon switch.