Why do certain compounds show up again and again as reliable signals in insect behavioral and chemical ecology, with the same volatiles exhibiting broad functionality across a range of insect taxa? One possibility is that microbial species that are omnipresent in the environment are responsible for producing these signals. Metabolic variation is relatively conserved across a wide range of yeasts, bacteria, and fungi, and many microbes may produce similar (or even the same) suite of volatile compounds as a byproduct of metabolic activity. Here, I discuss how exploratory efforts to improve codling moth attractants led to the isolation of a ubiquitous yeast-like fungus; subsequent characterization of the volatile profile produced by isolates indicated they emitted a set of alcohols and carboyxls with broad bioactivity to insects, and explained the emission source of some volatiles that were previously unknown. In field tests, we found that these compounds attracted a variety of Hymenopterans, Dipterans, Lepidopterans, and Coleopterans. Our work in this area showed that paying careful attention to phylloplane microbial species and the volatiles they produce on a given substrate can lead to the rapid development of new semiochemicals with potential application in pest management and monitoring. We further developed these findings into a set of general principles with wide application in chemical ecology.
