To avoid yellow fever, try not wearing yellow.
Some colors may be more attractive to the Aedes aegypti mosquito, which carries the deadly disease, as well as Zika virus, chikungunya and dengue, according to a new study.
The findings from University of Washington researchers add depth to our understanding of the pest’s behavior, and more ways to stave off their troublesome — and sometimes deadly — attacks.
Their findings aren’t just helpful for those looking to avoid getting eaten up this summer. The study also bears significance for the millions globally who suffer mosquito-borne diseases annually, an estimated 1 million of whom will die from their contagious bite.
For most animals, the senses are adapted to find food, fast. However, little was previously known about the colors that attracted them.
Observation of how mosquitoes behaved given various scent and visual cues led scientists to identify which clothing colors had lured more mosquitoes. According to their findings, published this month in the journal Nature Communications, those colors are red, orange, black and cyan.
By contrast, some don’t do it for them at all — namely green, purple, blue and white.
First, it’s all the hot air we blow — specifically, carbon dioxide — that piques their interest.
“Mosquitoes appear to use odors to help them distinguish what is nearby, like a host to bite,” said study author Jeffrey Riffell.
Riffell, a professor of biology at UW, told Sci-News earlier this month, “When they smell specific compounds, like carbon dioxide from our breath, that scent stimulates the eyes to scan for specific colors and other visual patterns, which are associated with a potential host, and head to them.”
Their experiments tracked how mosquitoes responded to various visual stimuli, including their main meal, fleshy morsels of human hand.
But they needed the scent of carbon dioxide — which we can’t smell, by the way — to arouse their appetite.
Previous research had shown that the gas seemed to activate the mosquitos. And the new study demonstrated that, without it, they largely ignored all the colors.
Of course, one must breathe — so they turned to visual cues.
Even after a spritz of CO2, the mosquitos were unmoved by whites, greens, blues and purples. But red, orange, cyan and black had them hankering for human.
That’s probably because many of those colors can be seen on the surface of human skin. “Human skin — irrespective of skin tone or pigmentation — has a lower peak in the green wavelength,” the researchers noted in their report, referring to colors with shorter wavelengths on the visible color spectrum: green, blue and violet.
So it really comes as no surprise why these blood suckers prefer colors of longer wavelengths, red, orange and yellow. They added, “Sensitivity to orange and red correlates with mosquitoes’ strong attraction to the color spectrum of human skin.”