Neuroethology of Insect Olfaction and Its Practical Application to Agriculture and Homeland Security

NON-TECHNICAL SUMMARY: Concern by society over toxic chemicals in our food, in and around our homes, and in the environment, has made it imperative that more biorational, efficacious means of insect management be developed. This project examines the neurophysiological and behavioral mechanisms involved in olfactory communication in insects in order to improve the utilization of attractants in urban and agricultural IPM and also to improve the sensitivity and discrimination ability of tissue-based olfactory biosensors modeled after insect olfactory systems.
<P>APPROACH: For isolating and identifying chemicals from natural sources that might be useful in integrated pest management, either for direct control or for complementary roles such as monitoring, we will use behavioral and neurophysiological assays, followed by identification and synthesis using newly acquired instruments in my laboratory here at Penn State University. Unknown, behaviorally active volatiles will be isolated using a variety of techniques, including combined gas chromatography/electroantennography (GC/EAG) and combined gas chromatography /single cell recording (GC/SC). For the subobjective of determining the mechanisms by which insects respond to semiochemicals that affect mate-finding and host-finding, a new element in this work will be to examine how the strands of odors comprising the odor plumes that are involved in host finding interact with the olfactory systems of insects to either augment or depress the response to mate-finding odors such as sex pheromones. We will examine the mechanisms involved in controlled flight switched on by pheromones or host-odors, including optomotor anemotaxis and self-steered counterturning. For flight responses, as well as those involving walking or movement of body parts, we will determine the speed of the behavioral reactions to the onset and loss of the semiochemical stimulus. We will attempt to determine the temporal and spatial structure of the natural stimulus as well as its chemical composition and concentration. We will further develop our existing olfactory sensor to enable it to have the ability to detect and discriminate volatiles emitted by agents of harm such as explosives; drugs; toxins and bi-products of microbial fermentation facilities. The completed sensor will be based on the design of an existing insect antenna-based biosensor that has proven its ability to detect target odors such as DNT in real time as they are transported in odor plumes. The existing biosensor is able to discriminate these target odors from other odors even amongst intermingled plumes of this background odor. The fully developed sensor will operate by being trained to recognize certain signature volatiles emitted by drugs, toxins and the degradative biproducts of explosives, and then to emit a positive signal when the target odor is detected during test operation. The sensor will be coupled with wind and GPS information that will give it the capability of locating the source of target odor in a stand-off scenario by means of triangulation to the source. The final sub-objective is to perform research that will develop and further improve the utilization of semiochemicals for monitoring, disruption, and attract-and-kill (baits). The goal is to develop strategies for using identified semiochemicals, and to optimize the field efficacy of these compounds, including improving the controlled-release formulations in order to optimize the longevity and economical dissemination of active amounts of semiochemicals.