topic, this paper will discuss some of the chemistry involved in various aspects of the sex pheromone communication system in insects.

The sex pheromone communication system basically involves the release of specific chemicals from a pheromone producer (emitter), the transmission of these chemicals in the environment to a receiver, and the processing of these signals to mediate appropriate behavioral responses in the receiver. The chemicals transmitted downwind have been the most obvious targets for characterization. The code was first broken with the publication in 1959 (3) of the sex pheromone for the domesticated silkworm Bombyx mori after extraction of a half million female silkworm pheromone glands and 30 years of classical chemical analyses. The pheromone was found to be (E10, Z12)-hexadecadien-1-ol, which was called bombykol. This work showed that there was nothing magical about the communication system, and chemists around the world were "attracted" to this area of research on insect pheromones.

Research on the isolation and identification of various chemical signals used for mate attraction in insects has progressed through stages of improving technologies [e.g., capillary gas/liquid chromatography (GLC), airborne collectors, flight-tunnel bioassays, and powerful instrumental analyses on microsamples]. One of the most sensitive instruments used throughout the past two decades has been the electroantennogram (EAG) apparatus, which utilizes the male's antenna as a finely tuned detector for active materials. Schneider (4, 5) was the pioneer for setting up the EAG to carry out electrophysiological experiments on olfaction in insects. The sensitivity and specificity of the male's antenna to its own pheromone components made it a powerful tool in assaying for pheromone components and in predicting their structures (6). GLC retention times on nonpolar and polar columns of active compounds in crude female gland extracts could be determined quickly by collecting the GLC effluent in a separate capillary tube each minute and puffing air through each tube and across an isolated male antenna in the EAG setup. Depolarization of the isolated antenna in response to each puff is amplified and recorded or observed with an oscilloscope. The amplitude of response to active compounds was found to correlate to the frequency of generated nerve impulses, and thus, pheromone components in the extract elicited responses with the highest amplitudes.