Discovery of natural odors could help develop mosquito ...(the world. CO 2 emitted in human b...)

"CO₂ emitted in human breath is the main attractant for the Culex mosquito to find people, aiding the transmission of these deadly diseases," Ray said. "In our experiments we identified hexanol, and a related odor, butanal, as strong inhibitors of CO₂-sensitive neurons in Culex mosquitoes. These compounds can now be used to guide research in developing novel repellents and masking agents that are economical and environmentally safe methods to block mosquitoes' ability to detect CO₂ in our breath, thereby dramatically reducing mosquito-human contact."

Study results appear Aug. 26 in the advance online publication of Nature.

A video, "Combating West Nile Virus and other Tropical Diseases," is available here.

"This is a beautiful study that breaks new ground in the field of olfaction," said John Carlson, the Eugene Higgins Professor of Molecular, Cellular and Developmental Biology at Yale University, who was not involved in the research. "It shows that certain odorants can strongly inhibit the response of receptors that detect CO₂. The results suggest some very interesting new strategies for the control of certain insect pests."

Besides showing that inhibitory odors can play an important role in modifying insect behavior, the research paper also illustrates how some of these odors have a long-term effect. Ray and Turner found, for example, that some odors silenced the CO₂ neuron in the fruit fly well beyond the period of application.

"To our surprise, we found that exposure to a long-term CO₂ response inhibitor can exert a profound and specific effect on the behavior of the insect, even after the inhibitor is no longer in the environment," Ray said. "This means this odorant could potentially be used to keep mos
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