A group of scientists from the Unversity of Washington has noted that mosquitoes are sometimes flying towards specific colours such as red, orange, black, and cyan, after detecting a telltale gas in our breaths. And little creatures are often unaware of colors like green, purple, blue, and white.
These results can lead us to learn how they find their hosts, because human skin emits a strong red orange signal to their eyes.
Jeffrey Riffell, a UW biology professor & lead author of the study, said: “Mosquitoes seem to use smells to help them distinguish what’s nearby, such as a biting host.” When mosquitoes smell specific compounds, such as CO2 from our breath, “this scent stimulates the eyes to-scan specific colors & other visual patterns, which are associated with a potential host, and move towards them,” added Riffell.
The study results, published on Feb 4 in Nature Communications, reveal how the mosquito sense of smell, known as olfaction, affects how the mosquito responds to visual cues. Knowing which colors attract hungry mosquitoes and which don’t can help design better repellents, traps, & other methods to-keep mosquitoes at-bay.
Riffell says one of the most frequently asked questions is “what to do to stop mosquitoes from biting” and continued, “I was saying that there are three major signs that mosquitoes attract: your breath, your sweat & the temperature of your skin.
In this study we found a 4th cue: the color red, which is not only found on your clothes but also on everyone’s skin. The shadow of your skin does not matter, we all give-off a strong red signature. Filtering out these attractive colors on our skin or wearing clothes that avoid these colors could be another way to prevent a mosquito bite.
The team monitored the behavior of the female yellow fever mosquito Aedes aegypti when different types of visual and olfactory cues were presented. As with all mosquito species, only females drink blood, but A.aegypti bites can also transmit dengue yellow fever, chikungunya & Zika. The researchers tracked individual mosquitoes in miniature check chambers that were sprayed with specific odors and featured differing kinds of visual patterns — akin to a coloured dot or a tasty human hand.
In the absence of a stimulus of smell, mosquitoes have largely ignored a do at bottom of chamber, regardless of color.
After a CO2 spray in chamber, the mosquitoes continued to ignore dot whether it was green, blue or purple. But if dot was red, orange, black or cyan, mosquitoes would fly towards-it.
Previous research by various researchers indicates that the hunting activities of female mosquitoes increase and they begin to search perimeter after smelling CO2, a gas that we humans are unable to smell. The color dot experiments showed that after smelling CO2, the eyes of these mosquitoes prefer certain wavelengths in visual spectrum.
Imagine you are on a sidewalk & you smell baked goods, you would start looking for a bakery sign, right? Mosquitoes do-too.
We humans see color in different wavelengths of light, and the team doesn’t currently know if mosquitoes see color the way we do. However, experiments show that mosquitoes prefer longer wavelengths of light up-on smelling CO2.
Unfortunately for us, human skin emits a long wavelength signal in the red-orange range, regardless of pigmentation. To mosquitoes we are all very delicious-snacks walking about.
When Riffell’s team repeated the chamber experiments with human skin tone pigmentation cards — or a researcher’s bare hand, The mosquitoes again-to fly only after the visual stimulus after the CO2 was sprayed into chamber. If the scientists used filters to get rid of long-wavelength signals, or had the researcher wear a green-color glove, then CO2-primed mosquitoes not flew toward the stimulus.
Genes determine these females’ preference for red-orange colors. Mosquitoes with a mutated copy of a gene needed to smell CO2 no longer showed a color preference in test-chamber. “These experiments represent the first steps mosquitoes use to find hosts,” Riffell said.
The research was funded by the National Institutes of Health, the Air Force Office of Scientific Research, the University of Washington & US Army Office of Research.
Maybe a device that can adjust the color of the light could help protect us from mosquitoes, but you can always hit them with a small laser tank or play a Skrillex song from your speakers.