Research on a mosquito that transmits the West Nile virus won two awards for a University of California, Davis doctoral candidate at the recent Entomological Society of America's 56th annual meeting, held in Reno.

Wei Xu, a researcher in chemical ecologist Walter Leal's lab, received first place in the 2008 Overseas Chinese Entomology Student Research Paper Competition and second place in the student competition for the President's Prize in the Diptera category.

Xu's topic: "The Localization of Culex quinquefasciatus Odorant Binding Protein-1 (CquiOBP1)." Mosquitoes detect scents with the sensilla on their antennae.

“Wei was able to explain in simple terms how he pinpointed the sensilla on mosquito antennae that express a certain olfactory protein,” said Leal, the winner of the ESA's 2008 Recognition Award in Insect Physiology, Biochemistry and Toxicology, presented at the same meeting. “Because the sensilla is sensitive to an oviposition pheromone, the implication of his work is that the protein is a pheromone-binding protein. We are now using this protein as a molecular target for the development of novel mosquito oviposition attractants as part of our approach to fend off WNV transmission by mosquito bite.”

Xu is a Ph.D. student research assistant in the Agricultural and Environmental Chemistry Program (molecular biology and biochemistry section), housed in the Department of Entomology. Xu studies olfaction systems in mosquitoes.

A native of China, Xu is finishing his master's degree in entomology at UC Davis while also working on his doctorate in agricultural and environmental chemistry. He earlier received two degrees from Zhongshan University, Guangzhou, China: his bachelor of science degree in microbiology in 2001 and his master's in biochemistry and molecular biology in 2004.

The Leal lab drew international news coverage in August when Leal and Zain Syed revealed the mode of action for the mosquito repellent, DEET. The repellent, discovered more than 50 years ago and considered the "gold standard" of insect repellents, does not mask the smell or jam the senses, as previously thought. Mosquitoes avoid DEET because they dislike the smell.

Culex mosquitoes are the primary transmitters of the West Nile virus. So far this year, the disease has sickened 407 California residents in a total of 25 counties and killed 13 people. Counties reporting fatalities this year: Fresno, Los Angeles, Orange, Riverside and San Bernardino.