2012 Annual Report 1a.Objectives (from AD-416): To devise innovative methods for the suppression of insects that transmit diseases to the U.S. military deployed abroad. 1b.Approach (from AD-416): Identify and test compounds with insecticidal activity that makes them especially beneficial in the rapid control of mosquitoes, flies, and other arthropods responsible for carrying disease agent. Devise innovative means of applying control agents especially suited for use in combat or deployment conditions. Identify and test new classes of topical and area repellents for use by troops. 3.Progress Report: The mechanisms by which odors are detected by mosquitoes, including repellents have been poorly understood. We showed that odors including volatile repellents may stimulate a receptor, inhibit responses of a receptor to a second odor, or even enhance responses of a receptor to an odor. The odor or repellent exerts these different effects through separate sites on the receptor complex. This new knowledge will facilitate development of chemicals or combinations of chemicals aimed at disruption of mosquito behavior. A bioassay was developed to evaluate the behavior of mosquitoes in different physiological states. Initial results using the bioassay have correlated well with physiological studies of sensory receptors involved in the behavior.