Bug Off

Anyone who enjoys walking in the outdoors knows how easy it is for buzzing, swarming insects to spoil the occasion. There you are, experiencing the perfect hike along a beautiful trail on a fine fall morning, when suddenly all your energies are diverted to futile attempts to swat away the flying creatures flocking about your head and exposed skin.

What to do? Chemical countermeasures, of course, the most common of which is DEET (N,N-diethyl-meta-toluamide for the aficionado). Developed by the U.S. Army for use in the jungle, DEET sprays and lotions are now commonly available to anyone seeking relief from annoying bugs. It works well and many outdoorsy types wouldn’t leave home without it.

But how does DEET work on the molecular level? One theory posits that DEET blocks insect olfaction so they can’t smell your presence. A contrary notion is that DEET stinks, at least to insects, and they actively avoid you. Distinguishing between these two mechanisms has proven difficult, and there are numerous publications pro and con.

New work from a multi-institutional cooperation comes down squarely in favor of the former – that is, that DEET acts as a molecular “confusant,” effectively scrambling the insect’s ability to sense odors. The particular target receptor for DEET is a membrane ion channel that is modulated by odor molecules. A specific mutation in this structure can inhibit DEET binding and block its ability to ward off insects.

Luckily, the mutant is a Drosophila (fruit fly) from Brazil, a species not likely to be encountered by many readers. So enjoy your next hike confident that we know how DEET works and will likely continue to enjoy its relieving powers.

Tom Tritton is President and CEO of CHF.

Posted In: Technology

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