We studied the orientation of female Aedes aegypti to CO2 and skin odor in a laminar-flow wind tunnel. We varied the plume’s concentration, overall dimensions, and internal structure and verified these with a surrogate gas (propylene) and a photo-ionization detector. Our 3-D reconstructed flights show marked differences in the orientation behavior of mosquitoes to CO2 and skin odor. Contacts with thin (ribbon) CO2 plume induced short upwind surges, followed by casting. This in turn resulted in reiterative plume contacts and ultimately in high levels of source finding. Such a regular zigzagging pattern was not induced by contact with a ribbon plume of skin odor and very few mosquitoes located the skin-odor source. Broader skin-odor plumes increased upwind flight, but near straight upwind flights were observed only in homogeneous skin-odor plumes at high concentration. In contrast, turbulent CO2 plumes induced nearly straight upwind flights at low concentration. Tortuosity, which is the lateral and vertical displacement relative to the upwind displacement, increased with CO2 concentration and homogeneity. The results show that CO2 and skin odor induce different flight maneuvers and that the ‘optimal’ plume type differs between odors. These findings are of significance in research on mosquito ‘attractants’ and on trap design.
Species 1: Diptera Culicidae Aedes aegypti (Asian tiger mosquito)
Keywords: flight behavior
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA