Scientists discover mosquitoes use infrared to track humans down

By Dr. Avi Verma, MD

Mosquitoes have long been a nuisance to humans, but new research suggests they may be even more skilled at hunting us down than previously thought. It turns out our skin acts as a glowing infrared beacon, drawing these blood-sucking insects right to us. A study recently published in Nature sheds light on how mosquitoes use infrared sensing to locate their human prey, adding to what we already know about their ability to track us through smell and carbon dioxide in our breath.

How do mosquitoes use infrared?

Scientists at the University of California, Santa Barbara (UCSB) have discovered that mosquitoes have specialized infrared sensors located in their antennae. These sensors are tuned to detect heat emitted by human skin, which radiates at a temperature of around 34 degrees Celsius (93°F). This thermal radiation acts as a kind of invisible “neon sign,” guiding mosquitoes to exposed skin even in challenging environments, like during windy conditions or when the human target is moving.

According to UCSB molecular biologist Nicholas DeBeaubien, the mosquitoes they studied, particularly Aedes aegypti—a species notorious for spreading diseases like dengue, Zika, and yellow fever—are “exceptionally skilled at finding human hosts.” But because mosquitoes have poor eyesight and rely on other cues like body odor and carbon dioxide, infrared detection provides them with a reliable method of zeroing in on their next meal.

Mosquitoes and deadly disease

While in many parts of the world, mosquito bites are merely an annoying source of itchiness, they can also be deadly. Mosquitoes are responsible for more human deaths than any other animal on the planet, largely due to the diseases they spread. Malaria, spread by the Anopheles gambiae mosquito, caused over 600,000 deaths in 2022, according to the World Health Organization. In regions where mosquito-borne illnesses are prevalent, avoiding mosquito bites is critical for staying healthy.

This new understanding of how mosquitoes track humans using infrared could lead to the development of more effective defenses against these pests, potentially reducing the transmission of deadly diseases. For example, the research could pave the way for high-tech mosquito traps that use skin-temperature thermal radiation as bait.

The research behind the discovery

To investigate the role of infrared sensing, the research team at UCSB conducted a series of experiments using female mosquitoes—since only females drink blood. They presented the mosquitoes with dummy “hosts” that mimicked different aspects of human presence, including body temperature, CO2 (the gas we exhale), and specific body odors. Some of the setups included a thermoelectric plate set to 34 degrees Celsius to simulate human skin, while others were kept at ambient temperatures.

The results were telling. While infrared alone didn’t significantly attract mosquitoes, combining it with carbon dioxide and body odor made a huge difference. The mosquitoes’ attraction doubled when infrared was added to the mix, demonstrating how critical it is in helping them find us.

The team also confirmed that the temperature-sensitive protein responsible for detecting infrared, known as TRPA1, is located in the mosquitoes’ antennae. When the researchers removed the gene for this protein, the mosquitoes could no longer sense infrared, proving its importance in their hunting process.

What this means for you: Protecting yourself from mosquitoes

Understanding how mosquitoes use infrared to find us has practical implications for protecting ourselves. One effective measure is wearing loose-fitting clothing, which can help dissipate the infrared radiation that emanates from our skin, making us less visible to mosquitoes. This may explain why mosquitoes are less likely to bite through loose garments compared to tight-fitting clothes that cling to the skin and trap heat.

Additionally, the findings could lead to the development of better mosquito repellents and traps that disrupt mosquitoes’ ability to track us using infrared signals. While current mosquito defenses focus on masking human odor or repelling them with chemicals, future innovations may include traps that lure mosquitoes by emitting heat signatures similar to human skin.

The bigger picture: Health and mosquito-borne disease prevention 

Mosquitoes are more than just an itchy inconvenience. With diseases like malaria, dengue, and Zika still affecting millions globally, understanding how these insects target humans is crucial for public health. The discovery of their infrared-sensing abilities could be a game-changer in efforts to reduce the spread of mosquito-borne illnesses.

For now, the best ways to protect yourself include using mosquito repellents, wearing loose-fitting clothing, and avoiding outdoor activities during peak mosquito hours—dusk and dawn. As research continues, we may soon see new technologies and strategies that will help us better fend off these tiny but dangerous adversaries.

Stay tuned to IndoUS Tribune‘s Health Corner for more updates on this fascinating research and other ways to protect your health.