Infrared, the other super power of mosquitoes

How do mosquitoes detect their prey? We knew that they detected carbon dioxide. We learned that they also detect body heat.

The plagues of summer, mosquitoes have a field day drinking the blood of their victims, leaving a terribly itchy bite as a bonus. And this tireless question: but what attracts them to our homes?

Although mosquitoes have very poor vision, we already know that they are able to spot their prey thanks to the carbon dioxide it emits and odors, particularly that of sweat. Researchers at the University of Santa Barbara in California have just discovered that mosquitoes are also able to target infrared, that is to say, they detect from a distance the energy of the heat released by the body in the form of radiation.

To discover this superpower, the researchers used 80 female mosquitoes in laboratory tests. No live guinea pigs were sacrificed to endure the insects’ assaults. The scientists diffused a cloud of CO2 and the smell of sweat. They also used a plate with the same temperature as human skin on the surface, 34 degrees, while another plate had a neutral role with the ambient temperature of a hot country, around 29 degrees. And it was by studying the behavior of mosquitoes around these plates that the researchers were able to conclude that the smell and CO2 are indeed clues to spot humans but that from a distance of 70 cm, mosquitoes also detect infrared emitted by the body thanks to receptors located on their antennae. This explains why a mosquito that circles around you insistently and closely is difficult to chase away and always ends up finding a corner of skin or landing.

Does wearing clothes make us less detectable? Absolutely, this work has demonstrated it, they can serve in part as an “invisibility cloak” especially if they are large and loose, because they dissipate infrared radiation. Moreover, these results, which were published in the journal Natureshould also help us develop more effective mosquito traps in the future. And it is not just a question of comfort, but also of public health, because the Aedes aegypti mosquito that was studied here is one of the main vectors of transmission to humans of viruses such as dengue fever or Chikungunya.