Promising New Mosquito-Repellent Molecule Overwhelms Bugs' Sense of Smell

By Veronique Greenwood | May 10, 2011 4:26 pm

mosquito

What’s the News: Forget masking our scent or making us taste bad—sensory overload might be our most potent tool in repelling mosquitoes. And we might someday have a repellent for the job: Scientists have just discovered a molecule that zaps all of a mosquito’s odor receptors at once, overwhelming it. The molecule’s not ready to be deployed yet, but early tests indicate it could be thousands of times more effective than DEET.

How the Heck:

  • In the human olfactory system, a scent molecule—whether it comes from a banana, gasoline, or chocolate cake—binds to a receptor that’s tailor-made for it, triggering a neurological cascade that results in you perceiving that specific smell. But in mosquitoes, there’s an extra step: after the scent molecule binds to its special receptor, that receptor must bind to another, more general receptor to broadcast its signal.
  • What the team found is a molecule that can jam that second class of receptors, making them broadcast constant scent static. Since mosquitoes rely heavily on smell to detect their hosts, this would have a catastrophic effect on their ability to feed.

What’s the Context:

  • The current gold standard for insect repellent is N,N-Diethyl-meta-toluamide, also known as DEET, the stuff in Off! and other popular sprays. For a long time it wasn’t clear how DEET functioned—you may recall some speculation about it masking CO2, which we emit and which mosquitoes smell well—but a study in 2010 indicated that it’s just that DEET tastes and smells bad to them (as well as to us).
  • Predictably, DEET’s not totally harmless: it’s not supposed to be applied under your clothing or on damaged skin or left on for longer than needed. Researchers have been trying to figure out an alternative repellent that could be used for containing malaria, and they’ve have noticed that mosquitoes get confused when bright lights or overwhelming smells hit them. This new molecule (called VUAA1) could help us use that to our advantage.
  • In a nice touch, this team approached the problem of interfering with mosquitoes’ sense of smell as if they were searching for a drug: they bombarded the receptors with more than 118,000 molecules from a “library” of compounds and found VUAA1 when they noticed its unusual effects.

The Future Holds: More tests to see how effective the molecule is at repelling mosquitoes, and more investigation of related compounds to see what can be mostly easily developed into a safe and effective repellent.

Reference: Patrick L. Jones, Gregory M. Pask, David C. Rinker, Laurence J. Zwiebel. Functional agonism of insect odorant receptor ion channels. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1102425108

Image credit: poplinre/flickr

CATEGORIZED UNDER: Health & Medicine, Living World
  • Cyber

    Please hurry through the testing phase – Mosquitos find me especially tasty…and DEET sucks almost as much…

  • Bill

    Oh PLEASE let this test safe!! My wife and I are both mosquito magnets!!

  • Deacon.James

    I concur with the first two posts. Mosquito’s are for some reason more attracted to me than any one else in my family. I tell them its because I am sweeter than they are, thats when they say something rude, and my point is proven. :)

  • Jay Fox

    I get the impression that this as-yet unidentified molecule isn’t entirely safe. Otherwise, why spend effort on a search, unless it’s hideously expensive to make or acquire. Which is it? The article doesn’t say. And how do humans perceive it? Deet is so unpleasant to me, I’m willing to take my chances.

    I tend to be that guy who doesn’t get bit while sitting next to someone (usually my wife) who gets eaten alive. Not sure why or how that works.

    Now if these guys can get together with those guys who figured out the mosquito gut microbes, maybe they can design a lure/feeder and solve the problem that way. Get ‘em to go where you want, then feed ‘em microbes to take care of the parasites.

    If they can figure out what disrupts the mosquito, they should be able to figure out what really excites it, too. The two strategies could work together, one sending the pest away from us, the other attracting it to where we want, where it gets free food and medicine.

    We’ll never be able to wipe out all the mosquitoes, and probably shouldn’t want to. All the things that eat them would be in peril. But if we try to slightly modify their environment by working with nature instead of against it, we might at least be able to coexist.

  • anacondapdx

    Can this be applied to work on bedbugs too?! Portland has a definite problem with them.

  • http://www.crimeoutloud.co.za/ Claudio @ Crime in South Africa

    Very interesting. Does this apply to bugs in general or more targeted towards mosquitos?

  • http://www.windenergyadvocates.com/forum/index.php?action=profile;u=440574 Lorriane Takenaka

    Scientific American leans extremely far to the left. I quit subscribing in the 1980s because of their regular anti-US stance. And if your quoted section is indeed from them, they still don’t let reality (or science) get in the way of their biases.

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