Cicadas: The dormant army beneath your feet - Rose Eveleth

蝉：脚下的休眠大军 - 罗斯·埃弗里斯

翻译人员: Qingqing Mao 校对人员: Jenny Yang

If you live on the east coast of the United States,

如果你住在美国东海岸，

那过去的17年里，

you've spent the last 17 years of your life

walking, eating and sleeping

你走路、

吃饭、

睡觉，

above a dormant army of insects.

都在一支休眠的昆虫大军之上。

These are the cicadas.

这些昆虫是蝉。

Every 17 years,

每17年，

数十亿计的蝉从地下涌出

billions of them emerge from the ground to do three things:

来做三件事：

蜕壳，

molt, mate and die.

交配，

以及死亡。

There are 15 different broods of cicadas out there,

共有15窝不同的蝉，

grouped by when they'll emerge from the ground.

根据它们的出现时间来区分。

Some of these broods are on a 13-year cycle,

有些蝉窝的周期是13年，

others are on a 17-year clock.

而另一些是17年。

Either way, the cicadas live underground for most of their lives,

不管是哪一种，蝉的生命的大部分时间

都生活在地下，

feeding on the juices of plant roots.

依靠植物根的汁液存活。

When it's time to emerge,

等到要出现的时候，

the adults begin to burrow their way out of the ground

成虫会开始挖掘

离开地下的通道，

直到地面，

and up to the surface,

在那里它们将生活仅仅数周。

where they'll live for just a few weeks.

但是，在这几周里，

During these weeks, though,

everybody will know the cicadas have arrived.

所有人都会意识到蝉来了。

There will be billions of them.

它们有数十亿，

And they're loud.

而且他们很吵。

Male cicadas band together to call for female mates,

雄性蝉集结在一起，

来呼唤雌性配偶，

and their collective chorus can reach up to 100 decibels --

他们的合唱

可以高达100分贝，

as loud as a chain saw.

就像电锯的声音。

In fact, if you happen to be using a chain saw or a lawn mower,

事实上，如果你正在使用电锯

或是割草机，

male cicadas will flock to you,

雄性蝉会向你集结而来，

thinking that you're one of them.

以为你是它们的一份子。

和自然界的大部分东西一样，

Now, like most things in nature,

the cicadas don't arrive without a posse.

蝉的到来也不孤单。

There are all sort of awesome and gross predators and parasites

随着这些吵闹的虫子一起到来的，

还有各种可怕而又恶心的捕食者和寄生虫。

that come along with the buzzing bugs.

Take the fungus Massospora for example.

以团孢霉属的真菌为例。

这些白色的真菌将自身藏匿在蝉的腹中，

This little white fungus buries itself in the cicada's abdomen

侵蚀蝉，

and eats the bug alive,

leaving behind its spores.

并留下孢子。

当这些孢子破裂时，

When those spores rupture,

they burst out of the still-alive cicada,

它们会从依然活着的蝉的体内爆出，

turning the bug into a flying saltshaker of death,

把虫子变为一个播撒死亡的飞行盐罐，

raining spores down upon its unsuspecting cicada neighbors.

将孢子洒向

临近的毫无戒备的蝉。

虽然我们精确地知晓

But while we know pretty precisely

when the cicadas will arrive and fade away,

蝉何时会出现和消失，

we're still not totally certain of why.

我们仍然不完全了解其原因。

There are certain advantages

当然，让整个种群一下子出现

to having your entire species emerge at once, of course.

是有一定好处的。

The sheer number of cicadas coming out of the ground

从地下涌出的蝉的数量如此之多，

对捕食者而言是压倒性的。

is so overwhelming to predators, it is essentially guaranteed

这本质上保证了

总有一些虫子可以存活并繁衍。

that a few bugs will survive and reproduce.

And since cicadas emerge every 13 or 17 years,

由于蝉每13年或17年才出现，

这比很多捕食者的寿命都要长，

longer than the lifespan of many of their predators,

the animals that eat them don't learn to depend on their availability.

吃它们的动物

学着不去依赖它们的生存

但是，为什么是13年或17年？

But why 13 and 17 years,

instead of 16 or 18 or 12?

为什么不是16年？

或是18年？

或是12年？

Well, that part no one really knows.

这个没人真的知道。

It's possible the number just happened by chance,

有可能这些数字只是巧合，

或可能蝉真的很喜欢质数。

or, perhaps, cicadas really love prime numbers.

Eventually, the cicadas will mate and slowly die off,

最终，蝉会交配并慢慢死去，

their call fading into the distance.

它们的声音会渐渐弱下去。

The eggs they lay will begin the cycle again,

它们所产的卵会开始新的周期，

their cicada babies burrowing into the earth, feeding on plant juice,

蝉的幼虫会进入底下，

以树汁为食，

and waiting for their turn to darken the skies

等待它们的时候的到来，

来遮盖天际，

将它们的歌声弥漫各处。

and fill the air with their songs.

17年后它们会准备好。

In 17 years, they'll be ready.

Will you?

你呢？