Meeting Abstract
24.3 Jan. 5 Encoding navigational flight behavior to odors in the antennal lobe of Manduca sexta RIFFELL, J.A.*; CHRISTENSEN, T.A.; HILDEBRAND, J.G.; Univ. of Arizona; Univ. of Arizona; Univ. of Arizona jeffr@neurobio.arizona.edu
In insects, complex odor blends dictate behavior, where key odorants at specific ratios and concentrations are necessary for olfactory-mediated responses. Surprisingly, few studies have characterized and quantified the emissions of behaviorally critical plant odor blends that mediate insect behavior. As a result, studies in electrophysiology and behavior have not been realistically scaled to natural odor concentrations. To reach an improved understanding of the importance of odor blends in controlling behavior, and how the blends are encoded in the central nervous system compared to single odorants, we used the moth, Manduca sexta, and flower volatiles of its hostplant, Datura wrightii. Using a multidisciplinary approach by coupling volatile characterizations, behavioral wind tunnel experiments, and electrophysiology, we have been able to determine how complex blends, at natural concentrations, control flight behavior and are encoded in the antennal lobe (AL). By initially quantifying the complex floral-volatile emissions, we were able to realistically scale our odor concentrations and blend ratios used in behavioral and electrophysiological experiments. Through a combination of behavioral experiments and multi-unit recordings in the AL, we demonstrate the importance of certain odorant constituents in the blend that dictates M. sexta flight behavior. Moreover, by coupling multi-electrode recording with gas chromatography, we compared neural ensemble responses to single odorants in relation to the blend. Together, these results provide new evidence that in moths, upwind orientation to blends is mediated by the precise integration of multiple glomerular pathways, and that blend input transforms the network representations in a manner that is not predicted from responses to single odor compounds.
