为什么虫子有趋光性？- 每天聪明一点点 103：英语精读讲义

Hey, it's me, Destin.

嘿，是我，Destin。

Welcome back to Smarter Every Day.

欢迎回到 Smarter Every Day。

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

那么，你可能注意到了飞蛾和其他虫子有时会被困在光源周围。

Have you ever thought about why? 語法

你有没有想过为什么？

We're in the middle of the Amazon rainforest

我们现在在亚马逊雨林深处

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

Gerson 为我们架设了一盏巨大的水银灯

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

我们正在观察所有被吸引过来的不同物种。

This is Phil Torres.

这是 Phil Torres。

He is a

他是一位

What do you call it? 短語搭配

叫什么来着？

Entomologist.

Entomologist（昆虫学家）。

Entomologist?

昆虫学家？

Is that with a D or a T?

是拼作 D 还是 T？

With a T.

是 T。

Entomologist.

Entomologist。

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

所以，今晚我们要研究为什么这些昆虫会被光源困住。

The term for this is called phototaxis. 用詞

这个现象的专业术语叫做趋光性 (phototaxis)。

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

如果一个生物通过运动对光做出反应，它就具有趋光性。

A positively phototactic animal will move toward a light

正趋光性的动物会向光源移动

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

而负趋光性的不仅限于动物。

I guess

我猜

Think about it.

想想看。

Leaves are phototactic.

树叶就有趋光性。

So, here's what we're doing.

所以，这就是我们现在在做的。

They are going through

它们正在穿过

Are you taking photos of all the different species?

你在拍所有不同物种的照片吗？

Mhm.

嗯。

There's a good amount of

这里有好多

You got one on your ear.

你耳朵上有一只。

Hold on.

等等。

Got him.

抓到了。

Man, I've been moving around.

天哪，我一直在走动。

I haven't seen the same species twice.

我还没见过同一个物种出现两次。

Oh, that's a pretty one.

哇，那只很漂亮。

That is a crazy looking

那个长得好疯狂

Is that a moth?

那是一只飞蛾吗？

Yeah.

是的。

Is this how entomologists find new species?

昆虫学家就是这样发现新物种的吗？

Yes.

是的。

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

这是个非常好的方法，因为它们会直接飞向你。

You just kind of sit around?

你就只要坐在这里吗？

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

就只要坐在这里，晚上的不同时间会有不同的生物飞过来。

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

所以，我们现在看到的可能和大概3小时后看到的完全不同。

That's awesome.

太棒了。

What do you call these big ones, Phil?

Phil，这些大的叫什么？

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

那这个带着小……的小家伙呢？

Princess Leia ears? 文化背景

莱娅公主耳朵的？

I think that's a kind of silk moth.

我想那是一种天蚕蛾。

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. 短語搭配

我们已经证明了水银灯可以有效地将森林里的物种吸引到床单上。

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

但我们还没有回答我们的问题。

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

它们一开始为什么会被光吸引？

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

我很惊讶地发现关于这个主题的大部分文献

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

都是在五、六十和七十年代写的。

It's really old.

真的非常老了。

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

那么，我们打算这么做。

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

我从文献中找出了两种理论，我们将把它们都演示一遍。

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

这是我两年前弄到的一只老天蛾。

Check it out. 短語動詞

看看这个。

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

如果我们拿这个，把它和我从朋友 Jack 那里得到的月亮录像结合起来，

we can demonstrate theory number one.

我们就可以演示第一个理论。

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

飞蛾在自由飞行时利用太阳和月亮等天体来辨别方向。

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

这个理论是说，它们看到天空中的月亮，

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

并试图与月亮保持一个特定的角度。

Now, because the moon is so far away,

现在，因为月亮离得很远，

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

在它们飞行时，这个角度几乎保持不变。

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

现在，想象一下我们把月亮带到地球上。

As he goes underneath,

当它飞到光源下方时，

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

它的视角会变化得更快，它必须抬起头来补偿这个变化。

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

这最终使它的飞行方向指向光源远端的边缘外侧。

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

这会导致它飞出一个对数螺线，这用数学很容易定义。

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

我们应该可以观察那些飞蛾绕着水银灯飞行的画面，

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

然后弄清楚是否真的存在对数螺线，对吧？

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

我用 Phantom 高速摄像机录制了一些飞蛾绕灯飞行的高速画面，

in hopes of plotting that logarithmic curve, 短語搭配

希望能画出那条对数曲线，

but because the generator was running on AC, 用詞

但因为发电机用的是交流电 (AC)，

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

灯光一直在闪烁，所以我决定干脆不分析这段视频了。

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

相反，我发现了一个叫 Steven 的陶工拍了一些照片并提交给了 Nat Geo（国家地理）。

His open shutter method proved to be more effective. 用詞

他采用的慢快门方法被证明更加有效。

Look at those curves.

看看那些曲线。

Do you see any logarithmic spirals?

你看到任何对数螺线了吗？

Kind of maybe, 語氣意圖

或许有一点，

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

但问题是，你可以看到好几只飞蛾直接朝着光源飞去。

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

这似乎推翻了我们的理论，不是吗？

This leads us to theory number two. 表達脈絡

这引出了我们的第二个理论。

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

如果你是森林里的一只飞蛾，你在侧面看到了一个小亮点，

you can assume that's a wide open area.

你可以假设那是一片开阔的区域。

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

因此，你可以自由飞行而不会撞到树木、树枝之类的东西。

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

所以，这个理论认为这些种类的飞蛾会将自己对准光源并直接飞向它。

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

所以，在查看了所有这些理论并进行了我自己的观察之后，

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

我拍下了知了绕着灯笼飞行的高速视频。

Something became painfully clear to me. 短語搭配

有件事让我感到痛苦地清晰。

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

科学界根本不知道为什么有趋光性的昆虫会被光吸引。

We think we know, but we don't. 表達脈絡

我们以为我们知道，但其实并不。

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

我的意思是，在最基础的层面上，我们不知道发生了什么。

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

连这么简单的事情人类都不知道。

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

我们观察这个现象已经有几百年了。

So, as long as humans have had fire, 語法

只要人类拥有了火，

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

我们就知道虫子会被人造光吸引。

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

所以，发明电击灭蚊灯之类的东西只是时间问题。

Hold on.

等等。

You buy a bug zapper, expect it to work.

你买个灭蚊灯，期望它能起作用。

Go.

开始。

There you go.

好了。

Sorry.

抱歉。

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

显然，这些东西并不像广告上说的那样管用。

Let me explain why. 表達脈絡

让我解释一下为什么。

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

所以，如果我对文献的理解是正确的，

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

更多的虫子会飞向紫外光，因为更多的虫子能看到那个波长。

Now, this is interesting,

现在，这很有趣，

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

但问题是，死在这些设备上的并不只有蚊子。

You might be doing more harm to the moth population 語法

你对飞蛾种群造成的危害

than you are actually doing to the mosquito population.

可能比对蚊子种群造成的危害还要大。

Mosquitoes are actually attracted to carbon dioxide,

蚊子实际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

这就是为什么他们会在这些东西底部放些辛醇之类的小插件。

One last thing.

最后一件事。

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

你看到灭蚊灯侧面的这些黑色挡板了吗？

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

它们出现在那里有一个非常具体的原因。

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

还记得我们提到过飞蛾或其他虫子会试图飞向

side of a light source instead of directly at it.

光源的侧面而不是直接飞向它吗。

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

那么，这些挡板的作用就是制造出多个小光源的错觉。

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

所以，当一只虫子飞过来并看到这些小光源时，

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

它会试图飞向其中一个光源的侧面，

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

而不幸的是，它直接飞向了通电的电网，

getting zapped. 語法

然后就被电死了。

Anyway, that's pretty interesting.

不管怎样，这非常有趣。

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

所以，飞蛾和其他虫子并不是仅仅依靠光源飞行。

They also use other cues like pheromones.

它们还会利用其他信号，比如信息素 (pheromones)。

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

我怎么知道飞蛾是利用信息素飞行的，尤其是在交配时？

I read it in a book while I was flying.

是我在坐飞机的时候从书上读到的。

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

你可能知道 Audible 赞助了 Smarter Every Day。

So, I recommend an audiobook.

所以，我推荐一本有声读物。

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

你可以免费下载它，这也算是支持了 Smarter Every Day。

Right now, I'm actually reading a book.

现在，我其实正在读一本书。

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

作者是一个叫 E.O. Wilson 的人，Edward Wilson。

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

他……他和我一样都去了阿拉巴马大学。

Pulitzer Prize winner.

普利策奖得主。

He's a really good guy.

他真是个很棒的人。

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

总之，有趣的是他是来自我那个州的昆虫专家。

Pretty cool.

非常酷。

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

我现在正在读的书叫《Letters to a Young Scientist》。

Right now, I'm reading about moth pheromones.

现在，我读到了关于飞蛾信息素的内容。

Pretty neat.

很有趣。

It's actually pretty good.

确实非常好看。

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

我让你快点看看窗外，这样你就知道我们在哪里了。

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

总之，《Letters to a Young Scientist》讲述了 Edward Wilson 漫长的职业生涯

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

以及他在研究昆虫时学到和没学到的东西。

Go check it out.

去看看吧。

The cool thing is you can learn from his mistakes

酷的是你可以从他的错误中学习

and the things that he did that worked.

以及他做的那些成功的事情中学习。

Go check it out.

去看看吧。

audible.com/smarter.

audible.com/smarter。

You can download a free audiobook.

你可以免费下载一本有声书。

Top link in the video description.

视频简介里的第一个链接就是。

That'll help me out.

那会帮到我大忙。

Thanks.

谢谢。

Have a good one.

祝你开心。

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

那么，这个理论是说在你飞行的时候，

the closing angle between,

这个接近角，在……之间，

thank you,

谢谢，

the bug and the moon,

虫子和月亮，

the artificial moon,

人造月亮，

will change

会发生变化

and he tries to keep it overhead

并且它试图让它保持在头顶上

and as he's flying,

随着它的飞行，

what's that?

那是什么？

Thank you.

谢谢。

As he's flying,

随着它的飞行，

he always keeps the quote moon on top of him

它始终把所谓的月亮保持在它的上方

and he just ends up in this rotational pattern.

最终导致了这种旋转的轨迹模式。