EFFECTS OF DECAPITATION AND PBAN INJECTION ON AMOUNTS OF TRIACYLGLYCEUOLS IN THE SEX-PHEROMONE GLAND OF MANDUCA-SEXTA (L)

The correlation between triacylglycerols containing conjugated diene f atty acyl moieties and pheromone aldehydes in the sex pheromone glands of females of Manduca sexta was investigated. Females decapitated 15 h after adult emergence neither called nor produced pheromone during t he natural period of pheromone production on the subsequent two nights . However, these females could be stimulated to produce sex pheromone for prolonged periods by repeated injection of synthetic pheromone bio synthesis activating neuropeptide (PBAN). Gas chromatographic analysis of methanolysis products of lipids extracted from the pheromone gland s of decapitated and intact females showed no differences in the amoun ts of fatty acyl precursors of pheromone. High performance liquid chro matographic analysis of the triacylglycerols containing conjugated die ne analogues of the pheromone components (diene TG), obtained 24 and 4 8 h after decapitation, showed that the total amounts of these compone nts were not affected by decapitation. The amounts of all diene TC pea ks declined significantly when decapitated females were stimulated to produce pheromone during a 7 h period by repeated injection of PBAN at 3 h intervals but recovered when pheromone production subsided. These results indicate that PBAN induces liberation of pheromone precursors from the triacylglycerols during pheromone biosynthesis but does not induce replenishment of this storage pool. (C) 1996 Wiley-Liss, Inc.