HORMONAL-REGULATION OF SEX-PHEROMONE BIOSYNTHESIS IN THE TURNIP MOTH,AGROTIS-SEGETUM

Pheromone production in the female turnip moth, Agrotis segetum, is un der the control of a brain factor. This factor was demonstrated to be a proteinaceous substance termed pheromone biosynthesis activating neu ropeptide-like substance (PBAN-like substance). The sex pheromone of S wedish A. segetum includes (Z)-5-decenyl acetate, (Z)-7-dodecenyl acet ate, and (Z)-9-tetradecenyl acetate as major components. Decapitation of a female decreased pheromone production significantly. Pheromone pr oduction was restored by injection of homogenates of either male or fe male brain-suboesophageal ganglion or the corp-era cardiaca alone. Phe romonotropic activity was also found in homogenates of the female thor acic ganglion and abdominal ganglion that were obtained during scotoph ase. Injection of female brain and thoracic ganglion homogenates made from insects during the scotophase induced two and four times as much Z7-12:OAc, respectively, as injection with similar homogenates from ph otophase. As little as one-eighth female equivalent (FE) brain homogen ate was sufficient to increase the amount of Z7-12:OAc. The effect of brain homogenate on pheromone liter reached its maximum after 30 min. The activity of the PBAN-like substance present in female brain extrac ts was not correlated to the age of the donor. Injection of hemolymph collected during either photophase or scotophase into decapitated fema les did not increase the pheromone titer. The target site of the PBAN- like substance was not the pheromone gland, and the ventral nerve cord was not involved in the transportation of the PBAN-like substance, wh ich implies a mode of action different from what has been reported in other moths. Brain homogenates obtained during photophase from females of African A. segetum, Spodoptera littoralis, or Ostrinia nubilalis a s well as synthetic Bombyx-PBAN also induced pheromone production in d ecapitated Swedish female A. segetum. (C) 1995 Wiley-Liss, Inc.