斑马条纹的秘密# Animals - 动物园
h*h
1 楼
科学家注意到，斑马头上的条纹非常细，它们在吃草时这个部位需要靠近地面，因此极
易受到蚊虫叮咬
北京时间4月9日消息，科学家现在终于了斑马身上的斑纹的用途，答案并非黑和白那么
简单。他们表示，尽管斑马身上的黑白条纹通常被认为是用来伪装的，但是这些斑纹的
进化是为了让携带疾病的苍蝇远离它们的可能性更大。
这听起来非常不可思议，研究显示，苍蝇发现自己很难降落在这些斑纹上，斑马身
上这种大小的条纹对驱赶这些小飞虫特别有效果。斑马小腿上的条纹非常细，苍蝇在吸
取母牛等其他动物的血液时，特别喜欢选择这个部位。而且斑马头上的条纹也很细，因
为在吃草时，它们的脑袋需要靠近地面。这种理论是由美国研究人员提出的，他们寻找
证据，用来支持有关斑马是如何获得它们的斑纹的各种解释。
科学家很快不再考虑斑马的斑纹只是作为伪装，让这种动物在不断变化的林地光线
下更难被发现的想法，这是因为斑马的很大一部分时间都是在开阔地度过的。另一种非
常受欢迎的理论认为，斑马身上的斑纹令食肉动物感觉眼花缭乱，因此导致它们更难判
断眼前猎物的大小和速度。然而美国加利福尼亚大学的调查发现，狮子对捕捉斑马特别
擅长。其他一些理论，例如这些斑纹的进化是为了帮助斑马在非洲炎热的骄阳下保持凉
爽；作为识别彼此和聚集到一起的一种方式，也被排除掉了。
该研究成果发表在《自然通讯》杂志上，研究人员表示，有可靠证据可以证明，斑
马和一系列它的近亲动物均用这种方式对抗蚊虫叮咬。他们称，斑马的短毛和冬季不换
毛的特点，可能使它们特别容易被叮咬，因此需要额外的保护。斑马可能也非常容易感
染这些飞虫携带的疾病。研究人员得出结论说：“解答斑马的斑纹这个谜题的答案就在
我们手边。”
The zebra’s striped coat is simultaneously extraordinary and stunning. So
wondrous, in fact, that many people have imagined it to be evidence of God’
s infinitely artistic hand. Over the years, there have been many more
rational explanations, but that all-important scientific consensus has
remained elusive.
Charles Darwin certainly found the zebra’s stripes to be a conundrum. In
The Descent of Man, he dismissed the idea they could act as camouflage,
citing William Burchell’s observations of a herd:
Their sleek ribs glistened in the sun, and the brightness and regularity
of their striped coats presented a picture of extraordinary beauty, in
which probably they are not surpassed by any other quadruped.
Although both males and female zebras are similarly striped, Darwin hedged
that “he who attributes the white and dark vertical stripes on the flanks
of various antelopes to sexual selection, will probably extend the same view
to the … beautiful zebra.” In other words, the stripes help males and
females make sensible choices about whom they mate with.
Alfred Russel Wallace begged to differ. “It is in the evening, or on
moonlight nights, when they go to drink, that they are chiefly exposed to
attack,” he wrote in Darwinism. “In twilight they are not at all
conspicuous, the stripes of white and black so merging together into a grey
tint it is difficult to see them at a little distance.”
There are other possibilities too. Perhaps the stripes act as some kind of
zoological barcode, allowing one individual to recognise another. It has
been suggested they could somehow help with thermoregulation. Or perhaps
they are there to deter parasitic flies.
Tim Caro of the University of California, Davis, has puzzled over
contrasting colouration in mammals before. Now, in a new study published in
Nature Communications this week, he and his colleagues have focused their
attention on the zebra.
They take a completely original approach, stepping back from one species of
zebra and attempting to account for the differences in patterning across
different species and subspecies of zebras, horses and asses. Is there
anything about the habitat or ecology of these different equids that hints
at the function of stripes?
“I was amazed by our results,” says Caro. “Again and again, there was
greater striping on areas of the body in those parts of the world where
there was more annoyance from biting flies.” Where there are tsetse flies,
for instance, the equids tend to come in stripes. Where there aren't, they
don't.
The idea that flies don’t like stripes dates back at least to 1930. Since
then, there have been several studies that have provided experimental
support, with flies preferring to alight on all-black or all-white surfaces
rather than on stripes. The authors also stress the burden of blood sucking
insects: both tsetse flies and horseflies are the vectors for significant
and often-fatal diseases in horses; they are probably also capable of
draining a significant amount of blood (several hundred millilitres in a day
, apparently).
The next step will be to come up with experiments that explore the vision of
biting insects such as tsetse flies and horseflies and a convincing
explanation for why they seem to have such an aversion to stripes. If these
are forthcoming, a scientific consensus may yet emerge, saving zoologists of
the future from a whole lot of zebra-based head-scratching.
Caro T et al (2014) The function of zebra stripes. Nature Communications.
Published 1 April 2014. doi:10.1038/ncomms4535
易受到蚊虫叮咬
北京时间4月9日消息，科学家现在终于了斑马身上的斑纹的用途，答案并非黑和白那么
简单。他们表示，尽管斑马身上的黑白条纹通常被认为是用来伪装的，但是这些斑纹的
进化是为了让携带疾病的苍蝇远离它们的可能性更大。
这听起来非常不可思议，研究显示，苍蝇发现自己很难降落在这些斑纹上，斑马身
上这种大小的条纹对驱赶这些小飞虫特别有效果。斑马小腿上的条纹非常细，苍蝇在吸
取母牛等其他动物的血液时，特别喜欢选择这个部位。而且斑马头上的条纹也很细，因
为在吃草时，它们的脑袋需要靠近地面。这种理论是由美国研究人员提出的，他们寻找
证据，用来支持有关斑马是如何获得它们的斑纹的各种解释。
科学家很快不再考虑斑马的斑纹只是作为伪装，让这种动物在不断变化的林地光线
下更难被发现的想法，这是因为斑马的很大一部分时间都是在开阔地度过的。另一种非
常受欢迎的理论认为，斑马身上的斑纹令食肉动物感觉眼花缭乱，因此导致它们更难判
断眼前猎物的大小和速度。然而美国加利福尼亚大学的调查发现，狮子对捕捉斑马特别
擅长。其他一些理论，例如这些斑纹的进化是为了帮助斑马在非洲炎热的骄阳下保持凉
爽；作为识别彼此和聚集到一起的一种方式，也被排除掉了。
该研究成果发表在《自然通讯》杂志上，研究人员表示，有可靠证据可以证明，斑
马和一系列它的近亲动物均用这种方式对抗蚊虫叮咬。他们称，斑马的短毛和冬季不换
毛的特点，可能使它们特别容易被叮咬，因此需要额外的保护。斑马可能也非常容易感
染这些飞虫携带的疾病。研究人员得出结论说：“解答斑马的斑纹这个谜题的答案就在
我们手边。”
The zebra’s striped coat is simultaneously extraordinary and stunning. So
wondrous, in fact, that many people have imagined it to be evidence of God’
s infinitely artistic hand. Over the years, there have been many more
rational explanations, but that all-important scientific consensus has
remained elusive.
Charles Darwin certainly found the zebra’s stripes to be a conundrum. In
The Descent of Man, he dismissed the idea they could act as camouflage,
citing William Burchell’s observations of a herd:
Their sleek ribs glistened in the sun, and the brightness and regularity
of their striped coats presented a picture of extraordinary beauty, in
which probably they are not surpassed by any other quadruped.
Although both males and female zebras are similarly striped, Darwin hedged
that “he who attributes the white and dark vertical stripes on the flanks
of various antelopes to sexual selection, will probably extend the same view
to the … beautiful zebra.” In other words, the stripes help males and
females make sensible choices about whom they mate with.
Alfred Russel Wallace begged to differ. “It is in the evening, or on
moonlight nights, when they go to drink, that they are chiefly exposed to
attack,” he wrote in Darwinism. “In twilight they are not at all
conspicuous, the stripes of white and black so merging together into a grey
tint it is difficult to see them at a little distance.”
There are other possibilities too. Perhaps the stripes act as some kind of
zoological barcode, allowing one individual to recognise another. It has
been suggested they could somehow help with thermoregulation. Or perhaps
they are there to deter parasitic flies.
Tim Caro of the University of California, Davis, has puzzled over
contrasting colouration in mammals before. Now, in a new study published in
Nature Communications this week, he and his colleagues have focused their
attention on the zebra.
They take a completely original approach, stepping back from one species of
zebra and attempting to account for the differences in patterning across
different species and subspecies of zebras, horses and asses. Is there
anything about the habitat or ecology of these different equids that hints
at the function of stripes?
“I was amazed by our results,” says Caro. “Again and again, there was
greater striping on areas of the body in those parts of the world where
there was more annoyance from biting flies.” Where there are tsetse flies,
for instance, the equids tend to come in stripes. Where there aren't, they
don't.
The idea that flies don’t like stripes dates back at least to 1930. Since
then, there have been several studies that have provided experimental
support, with flies preferring to alight on all-black or all-white surfaces
rather than on stripes. The authors also stress the burden of blood sucking
insects: both tsetse flies and horseflies are the vectors for significant
and often-fatal diseases in horses; they are probably also capable of
draining a significant amount of blood (several hundred millilitres in a day
, apparently).
The next step will be to come up with experiments that explore the vision of
biting insects such as tsetse flies and horseflies and a convincing
explanation for why they seem to have such an aversion to stripes. If these
are forthcoming, a scientific consensus may yet emerge, saving zoologists of
the future from a whole lot of zebra-based head-scratching.
Caro T et al (2014) The function of zebra stripes. Nature Communications.
Published 1 April 2014. doi:10.1038/ncomms4535
