Those stripes might be some of nature’smost effective insect repellent.
这些条纹可能是自然界最有效的驱虫剂。
Natacha Pisarenko/Associated Press
What’sblack, white and striped all over — except for its head?
什么东西除了头部外，全身都是黑白条纹?
Horseswearing zebra coats on a farm in Britain.
在英国的一个农场里，穿着斑马外套的马。
The animals weren’t attending a masquerade. They were dressed for studies investigating a mystery that has puzzled scientists for more than a century.
这些动物并不是为了参加化妆舞会。它们的盛装打扮是为了研究一个困惑科学家一个多世纪的谜团。
With solid coats of brown or gray, “most mammals are pretty boring,” said Tim Caro, who studies animal coloration at the University of California, Davis, and a co-author of a study published on Wednesday in PLOS One. “So when you see these bold patterns like on a giraffe or zebra, as a biologist you say, Why?”
“大多数哺乳动物的皮毛都是棕色或灰色的，”加州大学戴维斯分校研究动物颜色的蒂姆·卡罗说，他也是周三发表在《公共科学图书馆·综合》上一项研究的作者之一。“所以当你看到长颈鹿或斑马身上这些大胆的图案时，作为一个生物学家，你会问，为什么？”
At least since the days when Charles Darwin and Alfred RusselWallace were theorizing about evolution, scientists have debated the function of this sassy animal print. It’s been called camouflage to confuse big predators, an identity signal to other zebras and a kind of wearable air conditioner. Now most scientists agree that the function of a zebra’s stripes is to ward off biting flies that can carry deadly diseases.
至少从查尔斯·达尔文和阿尔弗雷德·罗素·华莱士提出进化论以来，科学家们就一直在争论这种时髦的动物印记的作用。它之前被认为是迷惑大型捕食者的伪装，识别斑马的身份信号，还可以帮助斑马保持凉爽。现在，大多数科学家都认为斑马条纹的功能是为了防止携带致命疾病的苍蝇的叮咬。
But what exactly is it about a zebra’s wardrobe that flies don’t like?
但是，苍蝇为什么不喜欢斑马的衣服呢?
The answer to that question has been hard to find. Zebras in the wild are not easy to get close to. So Dr. Caro and a colleague, Martin How, went to Hill Livery, a horse farm moonlighting as an orphanage and a conservation hub for captive zebras near the University of Bristol in Britain. With their students, they observed and filmed horse flies trying to bite zebras. They also dressed some horses in zebra print to see if it helped them avoid fly bites.
这个问题很难回答。野外的斑马并不容易接近。因此，卡罗博士和他的同事马丁·豪去了希尔·利弗利，这是在英国布里斯托尔大学附近的一个马场兼斑马保护中心。他们与学生一起观察并拍摄了试图叮咬斑马的马蝇。他们还给一些马穿上斑马纹的衣服，看看这是否有助于它们避免被苍蝇叮咬。
A horse dressed as a zebra to investigate fly behavior in England.
为了调查苍蝇的行为，英国的一匹马被装扮成了斑马。
School of Biological Sciences/University of Bristol
布里斯托大学生物科学学院
The flies pestered all of the horses and the zebras in the paddocks equally. But once they got close, the zebra stripes seemed to dazzle the flies so much that they couldn’t manage a controlled landing. Flies zoomed in too fast and either veered off just in time — or simply bumped into the zebra and bounced off. The flies didn’t seem to like the zebra coats on horses, either, but their bare heads were fair game.
在马场里，苍蝇同样地聚集在所有的马和斑马的周围。但当它们靠近时，斑马条纹似乎让苍蝇眼花缭乱，无法控制着陆。苍蝇飞得太快，要么及时转向，要么撞到斑马身上被弹开。苍蝇似乎也不喜欢马身上的斑马外套，但不会放过未覆盖的头部。
“Something is stopping the fly from realizing that it’s close to making a landing,” Dr. Caro said. “We don’t know what that is, but stripes are exerting an effect to the very last second.”
“某种东西阻止苍蝇意识到自己快要着陆了，”卡罗博士说。“我们不知道那是什么，但条纹一直在发挥作用，直到最后一秒。”
The only thing they can say for certain is that the high contrast between black and white most likely tricks the fly’s low-resolution vision, which relies on sensing movement.
他们唯一可以肯定的是，黑白之间的高对比度很可能欺骗了苍蝇的低分辨率视觉，这种视觉依赖于感知运动。
“It’s probably just blowing the fly’s vision away,” Dr. How said.
豪博士说，“这可能只是让苍蝇的视线消失了。”
In an optical illusion called the barber pole, diagonal stripes appear to move up or down, depending on which way the pole is rotating. Something similar could be happening as flies approach zebra stripes. From afar, the fly may interpret the object as gray, but as it moves closer, the zebra’s diagonal stripes may appear to be moving in false directions. As a result, a fly may think it’s headed toward open space instead of landing. Or perhaps the sudden appearance of stripes may overload the fly’s vision and startle it into a buzzing stupor.
在一种称为“理发店旋转灯”的视错觉中，斜条纹看起来是向上还是向下移动，取决于理发店旋转灯的旋转方向。当苍蝇接近斑马条纹时，可能会发生类似情况。从远处看，苍蝇可能认为物体是灰色的，但当它靠近时，斑马的斜条纹可能看起来像是朝着错误的方向移动。因此，苍蝇可能会认为它正飞向开放的空间而不是着陆。或者，突然出现的条纹可能会让苍蝇的视觉超负荷，让它吓得发呆。
The researchers are now conducting tests with coats of different patterns, contrasts and thickness, to see just what it is about the stripes that stops the flies. “By playing around with those variables, we’ll be able to get inside the head of the fly, or the eye of the fly, to work out what’s sort of confusing to it,” said Dr. Caro.
研究人员目前正在用不同图案、对比度和厚度的衣服进行测试，看看是什么原因让条纹阻挡了苍蝇。“通过研究这些变量，我们将能够深入到苍蝇的头部，或眼睛，找出它们感到困惑的地方，”卡罗博士说。
In the meantime, people planning on being around horses or horse flies may want to consider wearing zebra print rather than a solid to avoid being bitten. You should probably make your horse a twinset, too.
与此同时，在马或马蝇周围的人可能会考虑穿斑马纹的衣服，而不是一种颜色的衣服，以避免被叮咬。你还应该给你的马做个两件套。
（版权说明，转载自;科学猫科普）
