Drosophila melanogaster sex peptide stimulates juvenile hormone synthesis and depresses sex pheromone production in Helicoverpa armigera

Previous studies demonstrate that virgin female adult Helicoverpa armigera (Lepidoptera: Noctuidae) moths exhibit calling behaviour and produce sex ph eromone in scotophase from the day after emergence, and that mating turns o ff both of these pre-mating activities. In the fruit fly Drosophila melanog aster, a product of the male accessory glands, termed sex peptide (SP), has been identified as bring responsible for suppressing female receptivity af ter transfer to the female genital tract during mating. Juvenile hormone (J H) production is activated in the D. melanogaster. corpus allatum (CA) by S P in vitro. We herein demonstrate crossreactivity of D. melanogaster SP in the H. armigera moth: JH production in photophase virgin female moth CA in vitro is directly activated in a dose-dependent manner by synthetic D. mela nogaster SP, and concurrently inhibits pheromone biosynthesis activating ne uropeptide (PBAN)-activated pheromone production by isolated pheromone glan ds of virgin females. Control peptides (locust adipokinetic hormone, AKH-I, and human corticotropin, ACTH) do nor inhibit in vitro pheromone biosynthe sis. Moreover, SP injected into virgin H. armigera females, decapitated 24 h after eclosion, or into scotophase virgin females, suppresses pheromone p roduction. In the light of these results, we hypothesize the presumptive ex istence of a SP-like factor among the peptides transmitted to female H. arm igera during copulation, inducing an increased level of JH production and d epressing the levels of pheromone produced thereafter. (C) 1999 Elsevier Sc ience Ltd. All rights reserved.