Mosquito bites are a nuisance that we would like to do without. Could adapting the colors we wear keep us from being stung? Biologist Cassandra Edmunds explores this clue in The Conversation.
Without a doubt, finding yourself covered in mosquito bites quickly puts a damper on a pleasant summer evening. But more than just a nuisance, mosquitoes are also the deadliest creatures on Earth, due to the diseases they spread.
Much of the research is aimed at understanding their behaviors and prey preferences. We know that vision is an important sense in insect bites, a rule that mosquitoes do not escape. Although they don’t rely solely on what they see, scent and temperature do combine with visual cues to help them locate a host.
Previous research has sought to link particular colors (or the wavelengths of light that we perceive as distinct colors) to mosquitoes’ host-seeking behavior. The results, however, were not conclusive, with the same species showing preferences for different colors.
A recent study, published in February 2022 in the scientific journal NatureCommunications, is the latest to explore the attraction of mosquitoes to different colors. Could this research help us avoid being stung simply by adapting the colors we wear? We’ll see.
The researchers conducted a series of experiments with three species of disease-carrying mosquitoes: primarily Aedes aegyptibut also Anopheles stephensi Y Culex quinquefasciatus.
In one of their experiments, they used a wind tunnel equipped with cameras to track the flight paths of mosquitoes. A tunnel has been designed to encourage them to behave as naturally as possible.
On the floor of the tunnel there were two small colored dots, one representing the desired color (wavelength) and the other the control (white). Some of the color swatches were chosen to mimic different skin tones, including one that represents the color of suntan lotion.
In mosquitoes, only the females bite, as most species require a blood meal to complete the reproductive process. So, 50 female mosquitoes, mated but not fed, were released into the wind tunnel, where they would naturally seek out a host.
After one hour, carbon dioxide (COtwo) was released in the wind tunnel. COtwoexhaled by humans and other mammals, it is odorless to us: but mosquitoes can smell it and use this scent to guide them to a blood source.
Before the release of the olfactory stimulus, the mosquitoes oh egypt he largely ignored the colored circles on the floor, instead exploring the ceiling and walls of the tunnel. But once the COtwo was introduced, they began to study colored circles, especially when the wavelength increased from 510 nanometers (nm) to 660 nm.
These longer wavelengths represent colors at the orange and red ends of the spectrum, although mosquitoes oh egypt they were more attracted to red than to black. It should be noted that these orange to red wavelengths are the same as those emitted by human skin tones. Blue, green and purple did not attract mosquitoes any more than the control.
When skin color spots were used, they attracted more mosquitoes than the control, but no preference for a particular skin color was observed.
Previous experiments have shown that mosquitoes are more attracted to contrasting colors, such as a checkerboard pattern, than to a solid color. The researchers also showed the mosquitoes different spots on identical and contrasting backgrounds. The oh egypt they were more interested in places with high contrast to the background. Scientists believe that this helps mosquitoes to distinguish an object (person) from the background, even in low light. Therefore, contrast played a more important role in attracting mosquitoes than color itself.
as for oh egypt, an.stephensi he was drawn to black and red, with little interest in the lower wavelengths. Cx. quinquefasciatus showed interest in violet/blue and red (oddly, the opposite ends of the tested spectrum).
The researchers also conducted a separate experiment in insect cages to explore the attraction of mosquitoes to real skin tones. Six volunteers from different ethnic backgrounds were recruited to participate in this trial. The control was a white glove placed on one window and the volunteers’ hands were held one by one on the other window to see if mosquitoes were attracted to a particular skin color.
It seemed that the latter were more attracted to the hands than the white glove: but as with the tips, there was no preference for a particular skin color.
What to conclude from this?
This study highlights that mosquitoes are attracted to human skin colors, but only in the presence of COtwo, suggesting that the breath odor of a human or mammal may serve as an initial cue. This confirms previous research that revealed that COtwo attracts mosquitoes.
The researchers further found that color and contrast were important factors for oh egypt which revealed a preference for red, then black. The an.stephensi have expressed interest in colors similar to those of oh egypt, although preferring black to red. During this time, Cx. quinquefasciatus he was attracted to different colors.
As the researchers acknowledged, their experiments did not take into account some other factors that influence mosquitoes’ host choice. These include chemicals released by human skin, skin temperature, and sweat present on the skin. It would be instructive to include these factors in future experiments.
What does this mean for us who do not want to be bitten? You can try to dress in white, blue or green and avoid black, red and orange. Absolutely avoid red and black checkered patterns.
While tailoring clothing can reduce the risk of being bitten, there is no guarantee that it will do so or that it will be effective, especially given the apparent variation in color preferences between species. But these results suggest that with more research, color could become a lever of mosquito control.
Cassandra Edmunds, professor of forensic biology, University of Bournemouth
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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