Tribes in Africa, Australia and Southeast Asia have practiced this custom in cultural ceremonies and rituals for generations. Usually mixed with clay, chalk, ash, and cattle dung, white or gray paint has been previously thought to help people lower their body temperature in hot climates.
However, researchers at Eötvös Lorand University in Budapest, Hungary, concluded that these striped patterns also reduce the number of biting insects that are attracted to the naked flesh of humans living in the wild. The results of their work were published in the Royal Society Open Science journal.
It is known that insects bite zebras much less often than animals of the same color. Therefore, a group of researchers decided to find out if light streaks painted on people would have a similar deterrent effect. In their experiment, they used three store dummies: one with dark skin, one with lighter skin, and a dark skin model with white stripes. Each of them was covered with a thin layer of glue to capture the number of insects. The dolls were then stuck right in the middle of the meadow and left for eight weeks in the summer, after which the number of horseflies and insects on each "body" was counted.
Representatives of various tribes living in Africa, Australia, Papua New Guinea and North America apply white, bright yellow and beige stripes to their naked bodies (1-6). These patterns are used to decorate the body, express emotions, or as signs that indicate personal identity and / or group affiliation (16, 17). They are often driven by cultural rites (18, 19), and sometimes they can function as temperature control or camouflage (20,21).
The results were striking: the dark-skinned mannequin was 10 times more attractive to horseflies than the striped model, and twice as attractive as the fair-skinned model. The researchers believe the stripes disrupt the polarization of light reflected from human bodies, making them less attractive to horseflies and other insects.
Gabor Horvath, a researcher at the University of Budapest, believes that the insect repelling effect is only a pleasant bonus to this indigenous tradition, which is primarily of cultural significance. The purpose of the patterns is not to stop fly bites, in this regard, they were just lucky. At the same time, scientists are convinced that these people are well aware of the deterrent properties of such bodily drawings. In fact, painting with white stripes can be seen as an example of behavioral evolution and adaptation to the environment.
Typical patterns of bodypainting of different tribes living in Australia (21–37), Papua New Guinea (38–40) and North America (41–42) / © Royal Society Open Science
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Horsefly and other pest bites are a serious threat, as the insects suck human blood, transmitting a variety of serious diseases, including the potentially deadly swamp fever.