Whatever the great Mina says, from what world to what world the zebras are not in polka dots, but in stripes. Naturalists have been wondering for centuries about the reason for this extraordinary streak of their mantle: do they serve to blend in? To recognize each other? For the regulation of body temperature? None of this according to a study by a research group coordinated by Gábor Horváth of the Budapest University of Technology and Economics, Hungary, published in the Journal of Experimental Biology: those black and white stripes serve to keep gadflies and annoying bloodsucking insects at bay .
He is about to end up run over, his mother saves him
Whatever the great Mina says, from what world to what world zebras they are not polka dot, but striped. On because Naturalists have questioned themselves for centuries about this extraordinary streak of their mantle: they serve for blend in? To recognize each other? For the regulation of body temperature? None of this according to a study by a research group coordinated by Gábor Horváth of the Budapest University of Technology and Economics, in Hungary, published in the Journal of Experimental Biology: those black and white stripes are for keep gadflies and annoying bloodsucking insects away.
The vertical stripes would confuse, in fact, the brain of these "blood suckers", interfering with the reflection of the light and making the zebras not very visible. Because, to attract gadflies and mosquitoes it is precisely the reflection of the light of the water on the skin of the animals, which is generally horizontal. Thus, the vertical arrangement of the strips would free from parasites. And it's not just their location that matters: the researchers observed that colors also play an important role, since insects prefer brown-coated animals and that the black-and-white color scheme is less attractive.
According to Horváth, insects “are attracted to horizontally polarized light, because reflections from water are horizontally polarized and aquatic insects use this phenomenon to identify bodies of water where they can mate and lay eggs. However, even female blood-sucking horseflies are guided to victims by the linearly polarized light reflected by their skins. "
To find out all this, the scientists built models of black, white and zebra horses, discovering the latter were practically ignored. By modifying the width, density and angle of the stripes, then, it was possible to detect that the less attractive model was exactly the same one that represented the design on the mantle of the royal zebra. "Natural selection in areas like Africa must have pushed for zebras to evolve the least attractive coat for bloodsucking parasites - the researchers explained - and this coat is precisely the zebra one."
A hypothesis that takes up that of the entomologist Jeffrey Waage, who had already explained in 1980 that the multifaceted eyes of the mosca tse-tse they would have been ill-suited to perceive shapes in perspective and to distinguish striped shapes. But until now there had been no confirmations. Still, he explains Matthew Cobb, an evolutionary biologist ofManchester University , this study "does not rule out other hypotheses about the origin of zebra stripes".
In short, more than one factor could be involved in the characteristic stripes of the zebras and there is still much to discover about the mystery of the black-white stripes.
Roberta Ragni
