2. 考研
  3. A butterfly’s wings can have many jobs besides keeping the insect aloft. They may be called on to attract mates, to warn potenti

A butterfly’s wings can have many jobs besides keeping the insect aloft. They may be called on to attract mates, to warn potenti

admin2022-11-01  44
问题     A butterfly’s wings can have many jobs besides keeping the insect aloft. They may be called on to attract mates, to warn potential predators to stay away, to mimic other animals or even to provide camouflage. All of these roles, though, depend on their colouration— which is unchanging. This plays into the idea that butterfly wings are dead tissue, like a bird’s feathers or a mammal’s hair. In fact, that is not true.
    Nanfang Yu, a physicist at Columbia University, in New York, has been looking into the matter. One of his interests is the optical properties of biological materials. That has led him to study butterfly wings in more detail. And, in collaboration with Naomi Pierce, a butterfly specialist at Harvard University, he has now shown, in a paper published this week in Nature Communications, that butterfly wings are, indeed, very much alive.
    Initially, Dr Yu and Dr Pierce wanted to know how the insects keep their body temperatures up without their wings overheating. Unlike birds and mammals, butterflies do not generate enough internal heat to run their metabolisms at full pelt. Instead, they rely on outside heat sources—usually the sun—to bring their bodies up to speed. But their wings, being thin protein membranes, have a limited thermal capacity. Those wings can therefore overheat quickly if the insects bask too long in sunlight, or, conversely, can cool down too rapidly if they are flying through cold air.
    In their experiments, the two researchers used a laser to heat up spots on the wings of dozens of butterfly species. When the temperature of the area under the laser reached 40°C or so, the insects responded within seconds by doing things that stopped their wings heating up further. These actions included a butterfly turning around to minimise its profile to the laser, flapping its wings or simply walking away.
    Butterflies engaged in all of these heat-minimising activities even when the researchers blindfolded them. That suggested the relevant sensors were on the wings themselves. Dr Yu and Dr Pierce therefore searched those wings for likely looking sensory cells. They found some, in the form of neurons that resembled heat detectors known from other insects. They speculate that these are there to detect deformation of the wing—information an insect could use to control its flight pattern.
    The third discovery Dr Yu and Dr Pierce made to contradict the "dead wing" hypothesis was that some butterfly wings have a heartbeat. Anyone who has looked closely at a butterfly will know that its wings have veins. These carry a bloodlike fluid called haemolymph. For a long time, entomologists thought the only role of the veins was, by being pumped full of haemolymph, to inflate the wings to full stretch after a butterfly emerged from its chrysalis. Dr Yu and Dr Pierce have now found that in male hairstreaks the haemolymph shows a pulse of several dozen beats per minute.
In Paragraph 5, researchers blindfold the butterflies to________.
选项 A、obstruct their possible reactions
B、eliminate interference factors
C、measure optical sensitivity
D、probe the location of sensors
答案B
解析 根据题干关键词Paragraph 5和blindfolded可定位到文章第五段。该段第一句提到Butterflies engaged in all of these heat-minimising activities even when there searchers blindfolded them．(即使研究人员遮住蝴蝶眼睛，它们也会做出这些降低热量的行为)，这说明遮住蝴蝶眼睛是为了排除它们是因为视觉而感知到热量变化从而做出反应的情况，以证明翅膀上确实存在传感器。由此可知，选项[B] eliminate interference factors“消除干扰因素”为正确答案。
转载请注明原文地址:https://jikaoti.com/ti/b21iFFFM
0

考研英语一

相关试题推荐
随机试题
最新回复(0)