across your face right now. Yes, you,

在你的臉上，現在。是的，你。

and at some point, maybe now, maybe in a few days,

而在某些時候，也許是現在，也許是幾天後。

it's going to find a nice cozy pore in your skin

它將在你的皮膚上找到一個舒適的毛孔

and lay a single enormous egg.

併產下一個巨大的雞蛋。

Meet the face mites. They're smaller than a grain

見識一下面蟎。它們比一粒糧食還小

of sand, are a kind of arachnid like spiders,

的沙子，是一種像蜘蛛一樣的蛛形動物。

and they feast on the oil and cells in your skin,

它們以你皮膚中的油脂和細胞為食。

particularly on your oily nose, cheeks, and forehead.

特別是在你的油性鼻子、臉頰和額頭上。

Scientists suspect they've been living on us

科學家懷疑它們一直生活在我們身上。

since the dawn of humanity over 200,000 years ago,

自20多萬年前人類誕生以來。

and today, studies suggest practically every adult

今天，研究表明，幾乎每個成年人

on the planet has thousands of them.

在這個星球上有成千上萬的人。

Odds are you've been living with them your whole life.

估計你這輩子都和他們生活在一起了。

Babies quickly get them from their parents

嬰兒很快就會從父母那裡得到它們

a few days after birth, and once those face mites

出生後幾天，一旦這些面蟎

are on you, the only thing they enjoy as much

在你身上，唯一的事情，他們享受一樣多

as slurping oil and nutrients from your pores is

因為從毛孔中吸取油脂和養分的方法是

having sex all over your face.

在你臉上做愛。

Afterwards, females burrow deep

之後，雌性就深埋於地下

into your pores where they lay their eggs.

進入你的毛孔，它們在那裡產卵。

The eggs end up in one of two places

雞蛋最終會落入兩個地方之一

depending on the species of face mite.

根據面蟎的種類不同。

The first species, called Demodex folliculorum,

第一個種，叫Demodex folliculorum。

lays its eggs in your hair follicle,

在你的毛囊中產卵。

while the second prefers nesting in your sebaceous glands.

而第二種則更喜歡在你的皮脂腺裡築巢。

And in under two weeks, the babies hatch,

不到兩週，寶寶就孵化出來了。

mate, lay their own eggs and die,

交配，自己產卵，然後死亡。

leaving behind a pile of decomposing corpses.

留下一堆腐爛的屍體。

Now, you can wash some of this off,

現在，你可以洗掉一些這個。

but you'll never eradicate them completely

但你永遠也無法完全消除它們。

because even if you treat them with antibiotics,

因為即使你用抗生素治療他們。

they'll return in about six weeks, tops.

他們會在大約六週內返回，最多。

You'll pick them up from towels, pillows,

你會從毛巾、枕頭上撿到它們。

and your loved ones.

和你的親人。

Well, that all sounds horrific,

嗯，這一切聽起來很可怕。

but usually face mites are harmless.

但通常面蟎是無害的。

They only become a problem when they multiply

只有當它們繁殖的時候才會成為問題

out of control. This can happen in people

失控。這可能發生在人身上

with an impaired immune system.

免疫系統受損的情況下。

It's also been seen in people with a painful skin

也有的人出現了皮膚疼痛的情況。

condition called rosacea.

稱為酒糟鼻的情況。

Normally, you'll have around one or two mites

一般來說，你會有一兩隻蟎蟲。

per square centimeter of skin,

每平方釐米的皮膚。

but one study found that people with rosacea

但一項研究發現，有酒渣鼻的人。

had 10 times the normal amount.

了正常數量的10倍。

Believe it or not, in some cases,

不管你信不信，在某些情況下。

face mites can be useful.

臉上的蟎蟲可以有用。

Researchers can actually study your face mites

研究人員其實可以研究你的面部蟎蟲

to learn about your ancestors.

來了解你的祖先。

You see, most mites often stay within a community.

你看，大多數蟎蟲經常呆在一個社區內。

So over time, they've evolved into distinct lineages

所以隨著時間的推移，它們已經進化成了不同的血統。

in different geographic regions, and by comparing

在不同的地理區域，並通過比較。

their DNA, scientists can trace how different groups

科學家們可以追蹤不同群體的DNA

of humans migrated across the world.

的人類遷徙到世界各地。

For example, a study found that European mites

例如，一項研究發現，歐洲蟎蟲。

genetically diverged from East Asian mites

蟎類

around 40,000 years ago.

大約在4萬年前。

That's the same time European and East Asian humans

那是歐洲人和東亞人的同一時間。

parted ways. Pretty handy.

分道揚鑣了。很方便。

So when it comes down to bugs crawling all over you,

所以當你身上爬滿蟲子的時候。

it could be a lot worse.

這可能是一個更糟糕的。