Communication by Chemical Signals

Many organisms extract information about their environment by detecting and analyzing its chemical constituents. Compounds with such signaling properties are called pheromones if they are secreted to the outside by one individual and elicit a specific reaction, a definite behavior, or a developmental process in another individual of the same species. Mice, for example, have at least five distinct odors that differ in their behavioral or physiological significance-individual, alarm, male urine, group, and alien male odors. Although the chemical identity of such compounds is known in relatively few cases, evidence concerning their impact on the receiving organism, at the receptor, behavioral and hormonal levels is increasing. These compounds are used in transmitting what is often remarkably precise and complex information that can exert a powerful control over the relations between an animal and its external environment. What are the limitations and advantages of chemical as opposed to other forms of communication? How are pheromones able to alter the hormonal status of the individual? What are the receptor systems involved? Do such signals play a role in controlling primate behavior, including that of man? These problems were discussed by investigators representing psychology, zoology, physiology, organic chemistry, and perfumery at a meeting on "Communication by Chemical Signals" held in Auburn, Massachusetts, on 27 and 28 June 1968. The meeting was arranged by Clark University and sponsored by the U.S. Army Research Office. It is one thing to demonstrate that pheromones are implicated in the control of behavioral or physiological processes, but quite another to establish what receptor systems are involved. (Is it the vomeronasal or the olfactory organ in mice?) The main exception to this has been among insects, where the electrophysiological method-particularly that of Schneider, Boeckh, and their associates-has proved especially