经济学人下载:昆虫学—蝴蝶的翅膀(1)

A butterfly's wings can have many jobs besides keeping the insect aloft.
蝴蝶翅膀除了保持昆虫在空中飞行外，还有许多其他的功能。

They may be called on to attract mates, to warn potential predators to stay away,
它们可能被用来吸引配偶，警告潜在的捕食者远离，

to mimic other animals or even to provide camouflage.
模仿其他动物，甚至提供伪装。

All of these roles, though, depend on their colouration—which is unchanging.
然而，所有这些角色都取决于它们不变的色彩。

This plays into the idea that butterfly wings are dead tissue, like a bird's feathers or a mammal's hair.
这正好印证了蝴蝶翅膀是死亡组织的观点，就像鸟的羽毛或哺乳动物的毛发一样。

In fact, that is not true. For example, in some species males' wings harbour special cells that release pheromones which attract females.
事实并非如此。例如，在一些物种中，雄性翅膀上有特殊的细胞，这些细胞会释放信息素来吸引雌性。

Nanfang Yu, a physicist at Columbia University, in New York, has been looking into the matter.
纽约哥伦比亚大学的一名物理学家虞南方一直在研究这个问题。

One of his interests is the optical properties of biological materials.
他的兴趣之一是生物材料的光学特性。

That has led him to study butterfly wings in more detail.
这使他对蝴蝶翅膀进行了更细致的研究。

And, in collaboration with Naomi Pierce, a butterfly specialist at Harvard University,
他与哈佛大学一名蝴蝶专家Naomi Pierce进行合作，

he has now shown, in a paper published this week in Nature Communications,
并在本周发表于《Nature Communications》的一篇论文中表示

that butterfly wings are, indeed, very much alive.
蝴蝶的翅膀确实是活的。

Initially, Dr Yu and Dr Pierce wanted to know how the insects keep their body temperatures up without their wings overheating.
起初，虞博士和Pierce博士想知道这些昆虫是如何在不让翅膀过热的情况下保持体温的。

Unlike birds and mammals, butterflies do not generate enough internal heat to run their metabolisms at full pelt.
和鸟类及哺乳动物不同，蝴蝶不会产生足够的内热来进行新陈代谢。

Instead, they rely on outside heat sources—usually the sun—to bring their bodies up to speed.
相反，它们依靠外部热源—通常是太阳—来让身体加速。

But their wings, being thin protein membranes, have a limited thermal capacity.
但是它们的翅膀，由于是薄薄的蛋白质膜，所以热容量有限。

Those wings can therefore overheat quickly if the insects bask too long in sunlight,
因此，如果昆虫在阳光下晒得太久，这些翅膀会很快过热，

or, conversely, can cool down too rapidly if they are flying through cold air.
或者，相反如果它们在冷空气中飞行，就会很快冷却下来。

In their experiments, the two researchers used a laser to heat up spots on the wings of dozens of butterfly species,
在他们的实验中，两名研究人员用激光对数十种蝴蝶的翅膀进行加热，

including the painted lady and the hickory hairstreak.
包括小苎麻赤蛱蝶和山茱蝴蝶。

When the temperature of the area under the laser reached 40°C or so,
当激光照射的区域温度达到40℃左右时，

the insects responded within seconds by doing things that stopped their wings heating up further.
昆虫通过一些行为在几秒钟内做出反应，停止翅膀进一步升温。

These actions included a butterfly turning around to minimise its profile to the laser, flapping its wings or simply walking away.
这些动作包括转身，尽量不受激光的影响，拍打翅膀，或者干脆走开。