Mosquitoes Are Attracted to the CO2 We Exhale and the Color Red Study Shows

The mosquito has gained quite a menacing reputation. The sights and sounds of them inspired dread and repulsion. The mosquito saliva is home to some important pathogens like malaria, dengue fever, Zika, and Chikungunya. It goes without saying that mosquitoes are one of the downsides of a blissful summer. Everyone is so interested in how we can get rid of mosquitoes. New scientific evidence from the University of Washington shows that beyond adjusting your wardrobe there are other more important attractants that draw mosquitoes to your skin for a meal. These attractants include CO2 and red color from the skin. Averting the bite of mosquitoes may depend on how we can manage these two factors.


Malaria Mosquito

Malaria Mosquito

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Knowing the attractants that draw mosquitoes to your skin

The UW professor of biology and senior author, Jeffrey Rifell, explains that mosquitoes use the scent of gases like CO2 to stimulate their eyes to scan for particular colors like red indicating the proximity of a host.

The team used the females Aedes aegypti mosquito for this study. This species of mosquito carry the pathogen for yellow fever, Zika, and Chikungunya. In the lab, the mosquito was subjected to different scent and visual signals and was observed. Each mosquito was allowed a small compartment and sprayed with a particular gas or presented with particular visual signals like-colored dots or human hands.

Strikingly, the mosquito ignored color signals they were known to attack in the absence of appropriate odor stimulation. Conversely, they attacked those colors or bare skin as soon as CO2 was introduced to their chamber, however, when certain wavelength signals were removed or when the researcher covered his/her bare hand with green gloves, the mosquito stopped flying towards that signal. They continued to ignore dots of green, purple, or blue. In essence, they were only attracted to cues of red, orange, black, and cyan.

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At the core of the discovery, is the role of CO2 in the activity of mosquitoes. Humans and other animals exhale CO2, however, we can’t smell CO2. Sadly, the mosquito can! And utilize that advantage to tell the proximity of their host. Additionally, the Riffell team discovered that CO2 spikes the level of activity of female mosquitoes.

Noteworthy, was that females who had a mutation of genes coding red vision did not show a preference for red color. They needed to perceive CO2 to see red color.

Clinical significance

The technique can tip the odds in our favor, however, more studies have to be carried out to determine more visual and smell signals that alert mosquitoes when a target is within close range. This research has largely revealed how mosquito uses their olfactory sense to interpret visual signals—when to bite and when not to. This knowledge can help design mosquito repellants and traps that can help ward off or kill this insect.


Beating the bite of mosquitoes this spring and summer could hinge on your attire and your skin. The research has revealed that mosquitoes are guided to their hosts by CO2—the gas we exhale—and colors like red, orange, and black. No matter, the race, every human skin emits red signals. A lot remains to be uncovered to the other mechanisms that spell how mosquito locate their hosts. But this research can be the foundation on which stronger measures of controlling mosquitoes can be built.

Read Also: Mosquito Bites Latest Facts: Everything You Need to Know About Them


The olfactory gating of visual preferences to human skin and visible spectra in mosquitoes



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