The real reason why mosquitoes buzz | DIY Neuroscience, a TED series

Translator: Joseph Geni Reviewer: Krystian Aparta

譯者: Marssi Draw 審譯者: Regina Chu

(Mosquito buzzing)

（蚊子嗡嗡叫聲）

Greg Gage: We've all heard the annoying sound of a mosquito,

葛瑞格．蓋奇：我們都 聽過蚊子煩人的叫聲，

and we will stop at nothing to make it go away.

而且每個人都會不顧一切趕走牠。

While this sound may be maddening to us,

雖然這聲音讓人抓狂，

perhaps it's music to a mosquito's ears.

但也許對蚊子來說這是音樂。

The mosquito's nervous system has almost as many sensory auditory cells as we do.

蚊子神經系統的聽覺細胞 數量和我們的差不多。

But why would they have so many in such a small body,

但牠們身體這麼小， 怎麼聽覺細胞這麼多？

and why would they need to be so sensitive to sounds?

為什麼牠們必須對聲音這麼敏感？

答案是「愛」。

The answer is love.

[DIY Neuroscience]

[DIY 神經科學]

(Music)

（音樂）

As humans, we do a lot to attract each other.

人類會做很多事來吸引彼此。

Some things are conscious --

有些舉動是有意識的，

像是我們化粧， 或是讓自己有好氣味。

we put on makeup and make sure we smell nice.

但有些舉動是無意識的。

And some are unconscious.

You may unconsciously point your body or even sit closer to someone you like.

你可能會在無意識中 把身體朝向喜歡的人，

甚至坐得靠近一點。

這些是求偶行為，很多動物也都有。

These are courtship behaviors, and a lot of animals have them.

And mosquitoes are no different.

蚊子也不例外。

何莉這個夏天很勇敢地傾聽蚊子，

So Haley's been spending her summer bravely listening to mosquitoes,

and what she observed may surprise you.

她的發現會讓你大吃一驚。

So we want to investigate how the mosquitoes make their song.

我們想要調查蚊子怎麼創作歌曲。

So Haley, how do we record their wing beats?

何莉，我們要怎麼錄下蚊子翅膀振動？

Haley Smith: We need to tether them.

何莉．史密斯：我們得要綁住蚊子。

First, we anesthetize them in a fridge or a bed of ice.

首先，我們要麻痺蚊子， 把牠們放進冰箱或放在冰上。

And then I transfer them to this petri dish of ice,

然後我把牠們移到這片冰塊培養皿，

just to get them even more anesthetized.

讓牠們更麻痺一點。

Next, I take an insect pin,

接下來我拿一根昆蟲針，

and what I do is put a tiny little dab of superglue on this pin.

在上面沾一點強力膠。

I want to make sure that I get it on his thorax above his wings

我要確保這根針是放在 牠翅膀上方的胸部，

so that when he is suspended, his wings are still free to move.

這樣牠飛起來的時候， 翅膀還能自由移動。

So here's one down.

完成一隻了。

It's really hard to catch male mosquitoes in the wild

在野外要抓到公的蚊子很難，

because females are the only mosquitoes that are attracted to humans.

因為只有母的會被人類吸引。

They feed on human blood.

牠們喝人血。

And now, we can try to get some recordings from them.

現在，我們可以嘗試錄牠們的聲音。

So this is the stand that I use to hold them.

這是我用來固定牠們的檯子。

I like to place it right over the microphone

我習慣把牠們放在麥克風上面，

so that I can get a recording of the buzzing that you hear.

這樣我就可以錄到你聽到的嗡嗡聲。

That sound is generated by how fast they're beating their wings.

牠們振動翅膀的速度 會產生那個聲音。

這隻是公的。

This is a male.

The males have very bushy antennae, and they look kind of feathery.

公蚊子的觸角很多毛， 看起來有點像羽毛。

And they are also much smaller.

而且公的小多了。

GG: So he's flying at around 600 hertz.

葛：牠飛的大概在六百赫茲。

Can we try a female mosquito?

可以試一下母的嗎？

HS: Sure, here we go.

何：當然，馬上來。

(Mosquito buzzing, lower pitch)

（蚊子嗡嗡叫聲，頻率低一點）

GG: Wow.

葛：哇嗚！

HS: This is a much lower frequency than the male.

何：母的頻率比公的低很多。

GG: Yeah, it sounds completely different.

葛：真的，聽起來完全不一樣。

(Mosquito buzzing)

（蚊子嗡嗡叫聲）

(Mosquito buzzing, lower pitch)

（蚊子嗡嗡叫聲，低頻）

So is it because they're two different mosquitoes,

因為牠們是兩種不同的蚊子，

or because they're male and female?

還是因為不同性別？

HS: It's because they're male and female.

何：因為不同性別。

GG: Alright, let's verify that.

葛：好，我們來變化一下。

Can you bring in another female and see if she sounds

你可以抓另一隻母蚊子嗎？

來聽牠的聲音 是像第一隻還是第二隻。

like mosquito A or mosquito B?

HS: Yeah.

何：好啊。

(Mosquito buzzing, lower pitch)

（蚊子嗡嗡叫聲，低頻）

And again, she is much lower than the male.

一樣，這隻母的聲音比公的低。

GG: Yeah, she sounds different.

葛：嗯，牠的聲音聽起來不太一樣。

(Mosquito buzzing, lower pitch)

（蚊子嗡嗡叫聲，低頻）

Yeah, she's spot-on 400.

嗯，牠剛好四百赫茲。

HS: She really is. GG: That's really bizarre.

何：沒錯。 葛：還真是詭異。

HS: The females are at a much lower pitch. They were around 400 hertz.

何：母的頻率很低，大概四百赫茲。

HS: And all of the females were around that, too.

所有的母蚊子大概都這個頻率。

They were much larger than the males,

牠們比公的大很多，

so they didn't have to flap their wings as fast to stay in free flight.

所以保持自由飛行的時候 不必像公的振動那麼快。

GG: So they have larger wings, so they're flapping slower.

葛：牠們的翅膀大一點， 所以牠們的振動低一點。

And you noticed that all the females have the same frequency, roughly?

妳發現母蚊子大概都這個頻率，

And the males do, too. That's kind of interesting.

公的也是。真是有趣。

So that must mean something.

這一定有什麼含意。

Well, let's see what happens when we put the male and the female together.

我們來看看把公的和母的 放在一起會怎樣。

(Mosquitoes buzzing; pitch varies)

（蚊子嗡嗡叫聲，頻率會變化）

HS: When I put them into the same hearing range,

何：我把牠們 放在一樣的聽覺範圍裡，

I noticed that they were kind of changing their tones.

發現牠們會改變聲調。

It was kind of more dull, almost.

會變得沉悶一點。

(Mosquitoes buzzing)

（蚊子嗡嗡叫聲）

And when I put it back in my spectrogram to see their interaction,

我把牠們放回聲譜圖， 來看牠們的互動，

they were meeting at the same tone.

牠們的聲音一致。

GG: OK, pause.

葛：好，暫停一下。

The males and females are singing a duet,

公的和母的像在唱二重唱，

meaning that they adjust their wings to be able to produce a common tone.

也就是說牠們調整自己的翅膀， 來製造共同的聲調。

You have the male singing up here at G,

公的唱 G 調，

and you have the female singing down here at D,

母的唱低一點的 D 調，

and when they get together,

牠們合唱，

you're saying that they change the frequency of their wings

妳認為牠們改變翅膀的頻率

such that they come together?

來讓彼此湊在一塊嗎？

HS: Yeah, exactly. GG: And they sort of sing a duet.

何：沒錯。 葛：然後牠們像在唱二重唱。

(Mosquitoes gradually adjusting to identical pitch)

（蚊子嗡嗡叫聲 逐漸調整到同一個聲調）

HS: They're communicating to let each other know

何：牠們讓彼此知道

that they've basically found a potential mate.

對方找到了潛在的伴侶。

GG: So in other words,

葛：換句話說，

the female tends to choose a male that best sings her duet.

母蚊子傾向選和牠 合唱最好聽的公蚊子。

And studies have found that if she's pregnant,

研究發現如果母的懷孕，

she doesn't even bother.

牠們就不在乎了。

So if we can understand the mosquito mating behavior,

如果我們了解蚊子的交配行為，

we may be able to disrupt it in the wild and prevent diseases like malaria.

我們就能在野外干擾牠們，

避免一些疾病，像是瘧疾。

But for now, the next time you hear a mosquito buzzing,

但是你知道，下次你聽到蚊子叫，

just pause and remember she may be in love

只要暫停一下， 想想牠可能在熱戀，

and she may be singing her song,

牠可能在唱歌，

looking for her perfect match.

尋找牠的絕佳伴侶。

(Mosquito buzzing)

（蚊子嗡嗡叫聲）

(Smack)

（啪）