T. C. Baker, M. Maitani*, S.-G. Lee, K.C. Park, K. Borocsky, D.L. Allara*, J.V. Badding*, and J.H. Tumlinson

Center for Chemical Ecology, Department of Entomology *Department of Chemistry, Penn State University University Park, PA, USA 16802

We found that the cuticular lipid coatings on the surface of sensilla trichodea of Helicoverpa zea males facilitated the transport of certain pheromone-related molecules and impeded the transport of other molecules into the sensillar lymph of the sensilla. We used electrophysiological recordings employing both airborne puffs of candidate molecules and direct introduction of the molecules into the sensillum lymph using the saline recording electrode. We also employed atomic force microscopy (AFM) and chemical force microscopy (CFM) that showed that the chemical composition of the surface of a single sensillum is heterogeneous, with more hydrogen-bonding-friendly regions existing around the pores and pore tubules and under the many ridges that sculpt the terrain of the sensillum. Furthermore, the chemical composition of the sensilla trichodea of male H. zea and Manduca sexta was shown by GC/MS analyses to be dissimilar to the lipid coatings of other body parts.