PHEROMONOTROPIC ACTIVITY OF ORALLY-ADMINISTERED PBAN AND ITS ANALOGS IN HELICOVERPA-ZEA

Helicoverpa zea females do not produce pheromone during the photophase but can be induced to do so by injection of the pheromone biosynthesi s activating neuropeptide (PBAN). Based on this fact a bioassay was de veloped to determine if PBAN and its analogues could cause a pheromono tropic response when fed to the females. Starved photophase females fe d PBAN and its penta- and hexapeptide analogues in a sucrose solution did produce significant amounts of pheromone. Activity essentially fol lowed the same pattern as with injected peptides but was significantly lower in the feeding assay. Feeding with a radioactive hexapeptide an alogue indicated that up to about 30% radioactivity could be recovered from the haemolymph after 45 min. Haemolymph samples taken at various intervals after feeding PBAN, and analysed by ELISA, indicated a posi tive correlation between pheromone production and the presence of immu noreactive-PBAN. The results of this study indicate that PBAN and its analogues can cause pheromone production in photophase females after o ral administration and that the peptides do traverse the wall of the a limentary canal and appear in haemolymph.