After “put on a cardigan, it's refreshing”, usually comes “be careful with that color, it attracts mosquitoes”. Depending on which grandmother you ask, the problem may be in yellow, red, white or black. There are all kinds of opinions, but the truth is that not all have the same scientific basis. In fact, until recently there was not much scientific research on the subject. However, last February, a team of scientists from the University of Washington published a study analyzing why colors have more affinity the mosquitos.
What was known before is that they tend to be attracted by heat and carbon dioxide (CO2). Basically, females seek to feed by sucking on warm-blooded animals. If you look for the heat emitted by their bodies and the CO2 they release with their breath, it will be much easier to find them. It was suspected that the theme of heat also had a certain relationship with colors. After all, the darkest, like black, absorb more heat. And the truth is that, by mere observation, it was suspected that mosquitoes are crazy about dark colors.
But these scientists went a step further. What they did was take some mosquitoes of the species Aedes aegypti, and check what their favorite colors were, both in the presence and absence of their beloved carbon dioxide.
Mosquitoes' favorite colors
To carry out this study, its authors placed points of different colors in a chamber in which they later introduced the mosquitoes.
In some cases they sprayed the target with CO2, but in others they did not. Thus, they found that they were more attracted to dark colors with a high component red, orange or cyan. And also for black. On the other hand, white colors, like white, did not matter to them. But all this was only observed in the presence of carbon dioxide. If this gas was not sprayed into the chamber, the colors were indifferent to them.
This makes a lot of sense for the fact that we humans like us so much that mosquitoes do. After all, the color spectrum of our skin, regardless of hue, is dominated by red and orange wavelengths.
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Mutant studies
The next step in this study was to take genetically modified mosquitoese, with mutations in the photoreceptors that process the different wavelengths of the electromagnetic spectrum. Specifically, the opsin-1 and opsin-2 genes, which contain the information for the synthesis of short and long wave photoreceptors, were mutated. And also the receptor Gr3, involved in the processing of signals associated with carbon dioxide.
As much as we choose the color of our clothes with mosquitoes in mind, we will not prevent them from approaching us
They found that both longwave photoreceptor-related mutations and Gr3 mutations eliminated these preferences in mosquitoes. Therefore, this could be taken into account when introducing mutations in mosquito populations to prevent diseases transmitted by these insects. However, that would require more research.
At the moment, the only thing we can do to avoid them, especially in areas where they can transmit diseases, is to cover the as much skin as possible with clothing and avoid wetlands and areas where they are more concentrated. Could we avoid wearing orange, red or cyan? Yes, we could, but our skin would still be the same color. And we can't help but breathe either, so we have no choice but to resort to other options.
