Central processing of sex pheromone stimuli is differentially regulated byjuvenile hormone in a male moth

In the male moth, Agrotis ipsilon, the neuronal basis for juvenile hormone (JH)-linked modulation of sex pheromone responsiveness was investigated fol lowing stimulation of the antenna with i) an extract of female pheromone gl and, ii) the synthetic pheromone blends from A. ipsilon and a closely relat ed species, A. segetum, and iii) single components of the A. ipsilon blend. Response characteristics of olfactory interneurons were studied in the ant ennal lobe (AL) at different ages and with manipulated JH levels using intr acellular recording techniques. Blend-specific, generalist and component-sp ecific neurons were identified and described according to their response pa ttern. The proportion of low threshold AL interneurons increased significan tly with age for all stimuli tested. Changes were, however, less pronounced for the minor single components. The proportion of low threshold AL intern eurons in allatectomized (JH-deprived) mature males was significantly lower for all stimuli than in intact mature males. A large proportion of low thr eshold AL interneurons responding to the pheromone blends, but not as prono unced for single pheromone components, could be restored/induced by injecti ng JH either into JH-deprived mature males or into young immature males. Th e specificity for the species-specific blend compared to the A. segetum ble nd increased with age and JH injections. (C) 2000 Elsevier Science Ltd. All rights reserved.