For more than a century, the scientists around the world were trying to find an explanation for the bizarre color of the zebra. Why are there black and white stripes on its body and what purpose do they serve? A new research found surprising answers to these questions. For the past ten years, Tim Caro, a professor from the School of Biological Sciences at the University of Bristol, has devoted to the study of various theories of using the color of different animals for camouflage purposes, hunting for the prey, and adaptation to habitat conditions.
The scientists paid a special attention to zebras. It is widely believed that zebra stripes play a key role in the wild in dealing with predators. That color, according to one of the hypotheses, is capable of confusing predators, thereby preserving the zebra population.
But it turned out to be wrong and Tim Caro was able to prove it. He amassed enough evidence to show that the characteristic color of the zebra scares off blood-sucking insects, in particular horseflies and dangerous flies that carry infections. That assumption had never been considered before.
The scientist theorized that the stripes blind these insects, causing them to fly away, since the striped color gives a special result: the aperture effect. Other researchers supported their colleague. In fact, the aperture effect is a unique optical illusion known not only in the animal world, but also in the human world.
The visual perception of such stripes is formed in their upward movement, and not around their axis. And the scientists decided to check if that is how blood-sucking insects perceive the illusion.
A horsefly, approaching the surface of its landing, begins to adjust its speed depending on how quickly the surface expands in its field of view. But the stripes distort the optical flow of visibility due to the aperture effect, and because of that, the insect sees that the landing surface is much farther than expected.
Because of that, the horsefly cannot slow down and land at the intended place. These optical features were tested by a team of researchers in several experiments. Based on their results, the scientists concluded about the zebra stripes on its body.