Scientists Discovered A Novel Way Mosquitoes Find Humans — And How To Prevent It

Mosquitoes can be annoying at least and deadly at most. The pesky blood suckers not only induce itchy bites but they can also carry an array of disease-causing viruses from Zika to dengue and yellow fever. No wonder they are the world’s deadliest creature, according to the Centers for Disease Control. But how these critters seek out their prey is still fairly unknown. Now, in a new study, researchers found that mosquitoes use infrared to hunt down their prey.

A team led by researchers from the University of California, Santa Barbara conducted experiments that demonstrated mosquitoes’ ability to navigate toward a source using infrared radiation. They found that these bugs overwhelmingly navigated toward a source with body heat, rather than the one that just emitted odor and carbon dioxide. The team published this paper on August 21 in the journal Nature.

Focusing on the disease-spreading species Aedes aegypti, the researchers caged female mosquitoes and observed their host-seeking behaviors. There were two areas of the cage; both areas were exposed to human odors and carbon dioxide at the same levels that we exhale. One area, however, was also exposed to infrared radiation at skin temperature. Separated from these sources by a mesh barrier, the mosquitoes could sense these sources. The researchers then kept track of how many mosquitoes were searching for blood. The infrared source doubled the insects’ host-seeking activity.

Infrared radiation’s energy might be stimulating heat-sensing neurons at the tips of the mosquitoes’ antennae. Researchers know that mosquitoes use a temperature-sensitive protein called TRPA1 in the end of the antennae. The UCSB team found that when the gene that codes for the TRPA1 protein didn’t function, those insects couldn’t detect infrared radiation.

This finding may help explain why loose-fitting clothing is better than tight clothing at preventing bites. While it prevents the mosquito from reaching skin, it also prevents heat buildup. Heat also dissipates faster away from the body. So if you’re heading outside before the end of the summer, remember to wear loose-fitting clothing to reduce your infrared radiation — it’s a mosquito magnet.