Mosquitoes think DEET stinks

DAVIS, Calif., Aug. 21 (UPI) -- After 50 years, U.S. researchers say they have figured out why DEET, long "the gold standard" of insecticide repellents, works: It smells bad to them.

It has been long accepted that insect repellents containing the ingredient developed by the U.S. Army in 1946 known as DEET -- N,N-diethyl-3-methylbenzamide -- effectively keeps mosquitoes away.

But it took a University of California-Davis study led by Walter Leal and published in the Proceedings of the National Academy of Sciences to finally explain why.

Leal and Zain Syed discovered the exact neurons on the antennae that detect DEET. These neurons are located beside other neurons that sense a chemical, 1-octen-3-ol, known to attract mosquitoes. Mosquitoes detect DEET and other smells with their antennae.

The Davis study corrects "long-standing erroneous dogma," Jim Miller, an entomologist at Michigan State University said.

"For decades we were told that DEET warded off mosquito bites because it blocked insect response to lactic acid from the host -- the key stimulus for blood-feeding," Miller said in a statement. "One of the great attributes of science is that, over time, it is self-correcting."