In many places, the drone of a nearby mosquito is more than annoying–it’s dangerous. These insects transmit a variety of diseases, including yellow fever and malaria.
Scientists have now identified a protein that certain mosquitoes use to home in on human skin. This receptor, which resides on the surface of olfactory cells, senses 4-methyphenol, a molecule found in human sweat. John R. Carlson of Yale University and his colleagues reveal the finding in the Jan. 15 Nature.
In 1999, Carlson’s group and another research team reported that studies of the common fruit fly had uncovered insect odor receptors for the first time (SN: 4/10/99, p. 237). In the new work, Carlson and his colleagues took the gene for a putative odor receptor in Anopheles mosquitoes, the world’s most common carrier of malaria, and inserted it into fruit fly olfactory cells that are typically unresponsive to 4-methyphenol. The engineered cells exhibited a strong response to the compound, a good indication that the receptor is actually a means by which mosquitoes home in on sweat.
The receptor is made only in the olfactory tissue of female mosquitoes, which are the ones that feed on blood meals from people.
New mosquito repellents could be developed from compounds that block the receptor, or 4-methyphenol might work as a lure that could divert the insects from people, the researchers suggest. Indeed, 4-methyphenol has already been used to trap disease-carrying tsetse flies.
“Mosquitoes are likely to use multiple cues in seeking their human hosts, and the best repellents may be cocktails of multiple compounds,” says Carlson. “We’re now actively looking at other mosquito receptors to determine whether they respond to other human-sweat odorants.”
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