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  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  61
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.
Which of the following is true of butterfly wings according to the text?
选项 A、They turned out to be simple living organs rather than dead issue.
B、The role of veins is only to full inflate and stretch butterfly wings.
C、The neutrons found in wings carry haemolymph to create a heartbeat.
D、They are sensitive to ambient temperature due to sensory cells.
答案D
解析 从第四段可知蝴蝶的翅膀对于温度很敏感，而第五段中虞博士和皮尔斯博士进行实验。当他们遮住蝴蝶的眼睛时，蝴蝶也会做出一些降低热量的行为，且两位研究者还在蝴蝶翅膀上寻找感觉细胞(searched those wings for likely looking sensory cells)，结果是They found some，in the form of neurons that resembled heat detectors known from other insects．(他们发现了一些神经元，类似于其他昆虫的热探测器)，由此可知，选项[D]They are sensitive to ambient temperature due to sensory cells．(由于感觉细胞，蝴蝶对周围温度很敏感)是正确答案。
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