為什麼蟲子有趨光性？- 每天聰明一點點 103：英語精讀講義

Hey, it's me, Destin.

嘿，是我，Destin。

Welcome back to Smarter Every Day.

歡迎回到 Smarter Every Day。

So, you've noticed that moths and other bugs sometimes get trapped around a light.

那麼，你可能注意到了飛蛾和其他蟲子有時會被困在光源周圍。

Have you ever thought about why? 文法

你有沒有想過為什麼？

We're in the middle of the Amazon rainforest

我們現在在亞馬遜雨林深處

and we have a huge mercury vapor light that Gerson set up for us 片語動詞

Gerson 為我們架設了一盞巨大的水銀燈

and we are looking at all the different species that have shown up. 片語動詞

我們正在觀察所有被吸引過來的不同物種。

This is Phil Torres.

這位是 Phil Torres。

He is a

他是一位

What do you call it? 片語搭配

叫什麼來著？

Entomologist.

Entomologist（昆蟲學家）。

Entomologist?

昆蟲學家？

Is that with a D or a T?

是拼作 D 還是 T？

With a T.

是 T。

Entomologist.

Entomologist。

So, tonight we are studying why these insects get caught around the light.

所以，今晚我們要研究為什麼這些昆蟲會被光源困住。

The term for this is called phototaxis. 用詞

這個現象的專業術語叫做趨光性 (phototaxis)。

So, an organism is phototactic if it responds to light with motion.

如果一個生物透過運動對光做出反應，牠就具有趨光性。

A positively phototactic animal will move toward a light

正趨光性的動物會向光源移動

and a negatively phototactic animal doesn't necessarily have to be an animal.

而負趨光性的不一定非得是動物。

I guess

我猜

Think about it.

想想看。

Leaves are phototactic.

樹葉就有趨光性。

So, here's what we're doing.

所以，這就是我們現在在做的。

They are going through

牠們正在穿過

Are you taking photos of all the different species?

你在拍所有不同物種的照片嗎？

Mhm.

嗯。

There's a good amount of

這裡有好多

You got one on your ear.

你耳朵上有一隻。

Hold on.

等等。

Got him.

抓到了。

Man, I've been moving around.

天哪，我一直在走動。

I haven't seen the same species twice.

我還沒看過同一個物種出現兩次。

Oh, that's a pretty one.

哇，那隻很漂亮。

That is a crazy looking

那個長得好瘋狂

Is that a moth?

那是一隻飛蛾嗎？

Yeah.

是的。

Is this how entomologists find new species?

昆蟲學家就是這樣發現新物種的嗎？

Yes.

是的。

It's a really good way cuz they just come right to you.

這是個非常好的方法，因為牠們會直接飛向你。

You just kind of sit around?

你就只要坐在這附近嗎？

Just kind of sit around and different things come at different times of night.

只要坐在這裡，晚上的不同時間會有不同的生物飛過來。

So, what we see now may be completely different in like 3 hours.

所以，我們現在看到的可能跟大概3小時後看到的完全不同。

That's awesome.

太棒了。

What do you call these big ones, Phil?

Phil，這些大的叫什麼？

A sphinx moth.

天蛾 (sphinx moth)。

That's a sphinx moth?

那是天蛾？

And then what about this guy with a little

那這個帶著小……的小傢伙呢？

Princess Leia ears? 文化背景

莉亞公主耳朵的？

I think that's a kind of silk moth.

我想那是一種天蠶蛾。

Okay.

好的。

We've demonstrated that the mercury vapor lamp is effective in bringing the species out of the forest and onto the bedsheet. 片語搭配

我們已經證明了水銀燈可以有效地將森林裡的物種吸引到床單上。

But what we haven't answered is our question. 文法

但我們還沒有回答我們的問題。

Why are they attracted to the light in the first place? 片語搭配

牠們一開始為什麼會被光吸引？

I was surprised to find out that most of the literature on the subject 片語動詞

我很驚訝地發現關於這個主題的大部分文獻

was written in the '50s, '60s, and '70s.

都是在五、六十和七十年代寫的。

It's really old.

真的非常老了。

So, here's what we're going to do. 表達脈絡

那麼，我們打算這麼做。

I pulled out two theories from the literature and we're going to demonstrate them both.

我從文獻中找出了兩種理論，我們將把它們都演示一遍。

This is an old sphinx moth that I got 2 years ago.

這是我兩年前弄到的一隻老天蛾。

Check it out. 片語動詞

看看這個。

If we take this and we use it and combine it with some lunar footage that I got from my buddy Jack,

如果我們拿這個，把它和我從朋友 Jack 那裡得到的月亮影片結合起來，

we can demonstrate theory number one.

我們就可以演示第一個理論。

Moths use heavenly bodies like the sun and the moon to orient themselves in free flight. 講解

飛蛾在自由飛行時利用太陽和月亮等天體來辨別方向。

The idea is that they see the moon up in the sky

這個理論是說，牠們看到天空中的月亮，

and they try to keep themselves aligned at a certain angle with the moon. 文法

並試圖與月亮保持一個特定的角度。

Now, because the moon is so far away,

現在，因為月亮離得很遠，

that angle pretty much stays the same as they fly along.

在牠們飛行時，這個角度幾乎保持不變。

Now, imagine we brought the moon down to the Earth. 文法

現在，想像一下我們把月亮帶到地球上。

As he goes underneath,

當牠飛到光源下方時，

his viewing angle would change more rapidly and he has to pitch up in order to compensate for it. 講解

牠的視角會變化得更快，牠必須抬起頭來補償這個變化。

This ends up pointing him just beyond the far edge of the light source. 片語動詞

這最終使牠的飛行方向指向光源遠端的邊緣外側。

This would induce a logarithmic spiral, which is pretty easy to define with math.

這會導致牠飛出一個對數螺線，這用數學很容易定義。

We should be able to look at the footage of the moths flying around that mercury vapor lamp

我們應該可以觀察那些飛蛾繞著水銀燈飛行的畫面，

and figure out if there's a logarithmic spiral, right? 片語動詞

然後弄清楚是否真的存在對數螺線，對吧？

I used the Phantom to record some high-speed footage of those moths flying around the lamp

我用 Phantom 高速攝影機錄製了一些飛蛾繞燈飛行的高速影片，

in hopes of plotting that logarithmic curve, 片語搭配

希望能畫出那條對數曲線，

but because the generator was running on AC, 用詞

但因為發電機用的是交流電 (AC)，

that light was blinking and so I decided not to even analyze the footage. 文法

燈光一直在閃爍，所以我決定乾脆不分析這段影片了。

Instead, I found some photos that a potter named Steven took and submitted to Nat Geo.

相反，我發現了一個叫 Steven 的陶工拍了一些照片並提交給了 Nat Geo（國家地理）。

His open shutter method proved to be more effective. 用詞

他採用的慢快門方法被證明更加有效。

Look at those curves.

看看那些曲線。

Do you see any logarithmic spirals?

你看到任何對數螺線了嗎？

Kind of maybe, 語氣意圖

或許有一點，

but the problem is there's several moths that you can see flying directly in towards the light.

但問題是，你可以看到好幾隻飛蛾直接朝著光源飛去。

That kind of debunks our theory, doesn't it? 用詞

這似乎推翻了我們的理論，不是嗎？

This leads us to theory number two. 表達脈絡

這引出了我們的第二個理論。

If you're a moth in the woods and you see a little bright spot over to your side, 文法

如果你是森林裡的一隻飛蛾，你在側面看到了一個小亮點，

you can assume that's a wide open area.

你可以假設那是一片開闊的區域。

Therefore, you can free fly without getting hit by trees and sticks and stuff like that.

因此，你可以自由飛行而不會撞到樹木、樹枝之類的東西。

So, the theory goes that these species of moths will align themselves with a light and fly directly towards it. 片語搭配

所以，這個理論認為這些種類的飛蛾會將自己對準光源並直接飛向它。

So, after looking at all these theories and making my own observations, 文法

所以，在查看了所有這些理論並進行了我自己的觀察之後，

I took high-speed video of cicadas flying around lanterns.

我拍下了蟬繞著燈籠飛行的高速影片。

Something became painfully clear to me. 片語搭配

有件事讓我感到痛苦地清晰。

Science does not know why insects that are phototactic are attracted to light.

科學界根本不知道為什麼有趨光性的昆蟲會被光吸引。

We think we know, but we don't. 表達脈絡

我們以為我們知道，但其實並不。

I mean, at a base level, we don't know what's happening.

我的意思是，在最基礎的層面上，我們不知道發生了什麼。

This is such a simple thing for humans not to know. 文法

連這麼簡單的事情人類都不知道。

We've been observing this for hundreds of years. 文法

我們觀察這個現象已經有幾百年了。

So, as long as humans have had fire, 文法

只要人類擁有了火，

we've known that bugs are attracted to artificial light.

我們就知道蟲子會被人造光吸引。

So, it was only a matter of time before we invented things like the bug zappers. 慣用語

所以，發明電擊捕蚊燈之類的東西只是時間問題。

Hold on.

等等。

You buy a bug zapper, expect it to work.

你買個捕蚊燈，期望它能起作用。

Go.

開始。

There you go.

好了。

Sorry.

抱歉。

Obviously, these things don't work as advertised. 片語搭配

顯然，這些東西並不像廣告上說的那樣管用。

Let me explain why. 表達脈絡

讓我解釋一下為什麼。

So, if I read the literature correctly, 語氣意圖

所以，如果我對文獻的理解是正確的，

more bugs will go to the UV light because more bugs can see that wavelength.

更多的蟲子會飛向紫外光，因為更多的蟲子能看到那個波長。

Now, this is interesting,

現在，這很有趣，

but the problem is mosquitoes aren't the only type of bugs that is dying on these things.

但問題是，死在這些設備上的並不只有蚊子。

You might be doing more harm to the moth population 文法

你對飛蛾族群造成的危害

than you are actually doing to the mosquito population.

可能比對蚊子族群造成的危害還要大。

Mosquitoes are actually attracted to carbon dioxide,

蚊子實際上是被二氧化碳吸引的，

which is why they have these little inserts of octanol or something like that that they put in the bottom of these things. 講解

這就是為什麼他們會在這些東西底部放些辛醇之類的小插件。

One last thing.

最後一件事。

You see these black baffles on the side of the bug zapper?

你看到捕蚊燈側面的這些黑色擋板了嗎？

Now, that's there for a very specific reason.

牠們出現在那裡有一個非常具體的原因。

Remember how we talked about how a moth or another bug will try to go towards the 表達脈絡

還記得我們提到過飛蛾或其他蟲子會試圖飛向

side of a light source instead of directly at it.

光源的側面而不是直接飛向它嗎。

Now, what these baffles do is they create the illusion of multiple small light sources. 文法

那麼，這些擋板的作用就是製造出多個小光源的錯覺。

So, when a bug comes in and he sees those small light sources,

所以，當一隻蟲子飛過來並看到這些小光源時，

he tries to go for the side of one 片語動詞

牠會試圖飛向其中一個光源的側面，

and unfortunately, he goes directly in towards the electrified grid,

而不幸的是，牠直接飛向了通電的電網，

getting zapped. 文法

然後就被電死了。

Anyway, that's pretty interesting.

不管怎樣，這非常有趣。

So, moths and other bugs do not fly solely on light sources alone.

所以，飛蛾和其他蟲子並不是僅僅依靠光源飛行。

They also use other cues like pheromones.

牠們還會利用其他信號，比如費洛蒙 (pheromones)。

How do I know that moths fly with pheromones, especially while mating? 慣用語

我怎麼知道飛蛾是利用費洛蒙飛行的，尤其是在交配時？

I read it in a book while I was flying.

是我在搭飛機的時候從書上讀到的。

You might be aware that Audible actually sponsors Smarter Every Day. 語氣意圖

你可能知道 Audible 贊助了 Smarter Every Day。

So, I recommend an audiobook.

所以，我推薦一本有聲書。

You can download it for free and it helps Smarter Every Day.

你可以免費下載它，這也算是支持了 Smarter Every Day。

Right now, I'm actually reading a book.

現在，我其實正在讀一本書。

It's by a guy named E.O. Wilson, Edward Wilson.

作者是一個叫 E.O. Wilson 的人，Edward Wilson。

He uh he went to the University of Alabama just like I did.

他……他和我一樣都去了阿拉巴馬大學。

Pulitzer Prize winner.

普立茲獎得主。

He's a really good guy.

他真是個很棒的人。

Anyway, what's interesting is he is a bug expert from my state. 表達脈絡

總之，有趣的是他是來自我們州的昆蟲專家。

Pretty cool.

非常酷。

The book I'm reading right now is called "Letters to a Young Scientist".

我現在正在讀的書叫《Letters to a Young Scientist》。

Right now, I'm reading about moth pheromones.

現在，我讀到了關於飛蛾費洛蒙的內容。

Pretty neat.

很有趣。

It's actually pretty good.

確實非常好看。

I'll let you look out the window real quick just so you know where we're at. 文法

我讓你快點看看窗外，這樣你就知道我們在哪裡了。

Anyway, "Letters to a Young Scientist" is about Edward Wilson's long career

總之，《Letters to a Young Scientist》講述了 Edward Wilson 漫長的職業生涯

and what he learned and didn't learn while he was studying insects.

以及他在研究昆蟲時學到和沒學到的東西。

Go check it out.

去看看吧。

The cool thing is you can learn from his mistakes

酷的是你可以從他的錯誤中學習

and the things that he did that worked.

以及他做的那些成功的事情中學習。

Go check it out.

去看看吧。

audible.com/smarter.

audible.com/smarter。

You can download a free audiobook.

你可以免費下載一本有聲書。

Top link in the video description.

影片資訊欄裡的第一個連結就是。

That'll help me out.

那會幫到我大忙。

Thanks.

謝謝。

Have a good one.

祝你開心。

So, the theory is that as you're flying,

那麼，這個理論是說在你飛行的時候，

the closing angle between,

這個接近角，在……之間，

thank you,

謝謝，

the bug and the moon,

蟲子和月亮，

the artificial moon,

人造月亮，

will change

會發生變化

and he tries to keep it overhead

並且牠試圖讓它保持在頭頂上

and as he's flying,

隨著牠的飛行，

what's that?

那是什麼？

Thank you.

謝謝。

As he's flying,

隨著牠的飛行，

he always keeps the quote moon on top of him

牠始終把所謂的月亮保持在牠的上方

and he just ends up in this rotational pattern.

最終導致了這種旋轉的軌跡模式。