飞蛾如何利用鳞片躲避蝙蝠的追捕

This is Scientific American’s 60-Second Science. I’m Karen Hopkin.

这里是科学美国人——60秒科学系列，我是凯伦·霍普金。

Bats use echolocation to hunt for their meals, and moths are often on the menu.

蝙蝠利用回声定位来捕获食物，飞蛾也经常出现在它们的菜单上。

But in the acoustic arms race between predator and prey, moths also have a trick or two up their sleeve—or, actually, on their wings.

在这场捕食者和猎物之间的声音军备竞赛中，飞蛾也有一两个妙计——实际上，妙计就在飞蛾的翅膀上。

Because a new study shows that moth wings are covered with scales that absorb sound, particularly the ultrasonic variety preferred by bats.

因为一项新的研究表明，飞蛾的翅膀上覆盖着能吸收声音的鳞片，尤其是蝙蝠偏好的超声波。

So moth and butterfly wings are covered in layers of scales.

飞蛾和蝴蝶的翅膀上覆盖着层层鳞片。

These are made of a naturally occurring polymer called chitin, which is a polymer you find in most insect and crustacean exoskeletons.

这些鳞片是由一种叫做甲壳素的天然聚合物构成的，而在大多数昆虫和甲壳类动物的外骨骼中都能找到这种甲壳素的聚合物。

That’s Thomas Neil of the University of Bristol.

这是布里斯托尔大学的托马斯·尼尔。

He started out by bombarding bits of moth wings with sound and seeing what bounced back.

他先用声音轰击飞蛾的翅膀，观察反弹回来的情况。

We discovered that moth scales actually resonate in response to being hit with ultrasound.

我们发现被超声波击中时飞蛾鳞片会共振。

And they resonate at frequencies that pretty much perfectly match the frequencies that bats use for echolocation.

飞蛾鳞片共振的频率与蝙蝠用来回声定位的超声波频率几乎完全一致。

That vibration converts sound energy to mechanical energy, which muffles the echo that gets back to the bats.

这种振动将超声波的能量转化为机械能，从而减弱了传回蝙蝠的回声。

That probably hasn’t happened by accident, that these scales are such a shape and size that they’re resonating at just the right frequencies that they can absorb sound energy from hunting bats.

这可能不是偶然发生的，这些鳞片(具有特定形状和大小)的的共振频率恰到好处，它们能够吸收来自狩猎蝙蝠的声波能量。

Next, Neil and his colleagues modeled the sound-dampening capabilities of an array of different scales.

接下来，尼尔和同事对一系列不同鳞片的声波减震能力进行了建模。

The really cool thing about moths is their scales are all different shapes and sizes.

飞蛾最有趣的地方在于它们鳞片的形状和大小各不相同。

So what we found is that each individual scale will resonate at slightly different frequencies—and that, collectively, they actually absorb a really broadband range of frequencies.

因此，我们发现，每个鳞片的共振频率都有细微的差别，而且加在一起，它们能吸收的（声波）频率范围就很大了。

That range covers the frequencies of bat echolocation calls—findings Neil presented at the Meeting of the Acoustical Society of America.

这个范围涵盖了蝙蝠回声定位叫声的频率——尼尔在美国声学学会会议上介绍了这一发现。

So it means that the moths should be pretty well protected from a whole host of bats that they might interact with out in the wild.

这意味着，当在野外遇到了一大波与外界相互作用的蝙蝠，飞蛾也应该受到好好地保护。

But does the strategy actually work?

但是这个策略真的有效吗?

So we don’t actually know how effective these scales are at protecting moths in the real world.

我们实际上不知道在现实世界中，这些鳞片对飞蛾的保护效果如何。

But from everything we can model and measure and predict, it seems like they would have quite a considerable advantage in trying to hide these moths from bats hunting at night.

但根据我们所有的建模、测量和预测，这些鳞片似乎能在帮助飞蛾在夜间躲避蝙蝠中发挥很大的优势。

For any bats that might be listening, Neil says there’s not much you can do to thwart this moth maneuver.

尼尔表示，对任何可能在偷听的蝙蝠来说，没有多少办法能阻止飞蛾的这种策略。

The only real thing that they could do would be to call at higher amplitudes, so to increase the strength of their own echolocation calls such that the echo they got from a moth would be stronger.

蝙蝠唯一能做的就是发出更高振幅的超声波，这样就能增加回声定位的强度，这样它们就能从飞蛾那里得到更强的回声。

In other words, you might catch more moths with a shout than with a whisper.

换句话说，相比小声“嗡嗡”，蝙蝠们或许该用大声“吼叫”来捕捉更多的飞蛾。

For Scientific American’s 60-Second Science, I’m Karen Hopkin.

谢谢大家收听科学美国人——60秒科学。我是凯伦·霍普金。