Marcus Byrne: The dance of the dung beetle

Translator: Joseph Geni Reviewer: Morton Bast

翻译人员: Wei Wu 校对人员: dahong zhang

This is poo,

是的，这是真的便便

and what I want to do today is share my passion

而我今天来就是想跟大家分享

for poo with you,

我对便便的热爱

which might be quite difficult,

或许这很难让你接受，

but I think what you might find more fascinating

但是我想你大概会对这些小家伙们

is the way these small animals deal with poo.

处理便便的方法感兴趣的。

So this animal here has got a brain

这个小动物的脑子只有

about the size of a grain of rice, and yet it can do things

米粒那么大，但是它的能耐

that you and I couldn't possibly entertain the idea of doing.

超过了你我的想象。

And basically it's all evolved to handle its food source,

基本上它所有的能耐都是围绕着它的食物

which is dung.

也就是便便。

So the question is, where do we start this story?

现在，该如何开始说这个故事呢？

And it seems appropriate to start at the end,

看起来从（别的动物的）排泄开始比较合适

because this is a waste product that comes out

因为便便就是其它动物的排泄废物，

of other animals, but it still contains nutrients

但是它还是有营养成分的

and there are sufficient nutrients in there

对于蜣螂（屎壳郎）而言里面的营养成分

for dung beetles basically to make a living,

已经足够它们维持生命了

and so dung beetles eat dung, and their larvae

所以蜣螂靠吃便便生存，

are also dung-feeders.

它们的幼虫也靠吃便便生存。

They are grown completely in a ball of dung.

实际上它们就是在一个大粪球里长大的。

Within South Africa, we've got about 800 species of dung beetles,

在南非，人类已经发现了800种蜣螂

in Africa we've got 2,000 species of dung beetles,

在全非洲则发现了2000种，

and in the world we have about 6,000 species of dung beetles.

全球的蜣螂种类大概有6000种。

So, according to dung beetles, dung is pretty good.

所以，对蜣螂而言，便便味道是极好的。

Unless you're prepared to get dung under your fingernails

除非你下定决心用手把便便捡起来

and root through the dung itself, you'll never see

并仔细的检查，否则你可能会漏掉

90 percent of the dung beetle species,

世界上90%的蜣螂物种，

because they go directly into the dung,

因为它们会直接钻进便便里，

straight down below it, and then they shuttle back and forth

直直地钻下去，一直钻到地面，

between the dung at the soil surface

在地下造一个巢穴

and a nest they make underground.

然后在便便和巢穴之间来回穿梭。

So the question is, how do they deal with this material?

现在的问题是，他们如何处理这些食材？

And most dung beetles actually wrap it into a package of some sort.

大多数蜣螂都会以某种方式把便便打包。

Ten percent of the species actually make a ball,

大约10%的种类会把便便裹成一个球，

and this ball they roll away from the dung source,

然后把这个粪球滚到别的地方去，

usually bury it at a remote place away from the dung source,

经常会离发现便便的地方远一点。

and they have a very particular behavior

而它们在滚粪球这件事情上

by which they are able to roll their balls.

真的有一些独门绝技。

So this is a very proud owner of a beautiful dung ball.

现在你看到的蜣螂有一个裹的很好看的粪球。

You can see it's a male

从它腿后的一小撮毛可以看得出来

because he's got a little hair on the back of his legs there,

这是一只公蜣螂

and he's clearly very pleased about what he's sitting on there.

而且显然它对于自己屁股下面的东西很满意

And then he's about to become a victim

现在它马上就会遇到另一个坏蛋蜣螂

of a vicious smash-and-grab. (Laughter)

成为一个被抢劫的受害者。（观众笑）

And this is a clear indication

这也很清楚的体现出

that this is a valuable resource.

粪球是一个价值很高的资源

And so valuable resources have to be looked after

这么有价值的资源，需要用特殊的方法

and guarded in a particular way, and we think

小心的看护，而我们认为蜣螂之所以

the reason they roll the balls away is because of this,

要把（便便打包成）粪球推走也是因为这个原因，

because of the competition that is involved

因为如果想要占有整个粪堆的话，

in getting hold of that dung.

打来打去是免不了的。

So this dung pat was actually -- well, it was a dung pat

所以这个粪堆实际上——好吧，在照片拍摄的

15 minutes before this photograph was taken,

15分钟之前它还是一个粪堆，

and we think it's the intense competition

我们认为围绕粪堆的激烈斗争

that makes the beetles so well-adapted

造就了蜣螂非凡的

to rolling balls of dung.

滚粪球的能力。

So what you've got to imagine here is this animal here

你可以把蜣螂的旅程想象成

moving across the African veld.

穿越非洲大草原。

Its head is down. It's walking backwards.

它的头是朝下的，而且是倒着走。

It's the most bizarre way to actually transport your food in any particular direction,

最古怪的地方是蜣螂如何能够控制粪球的方向，

and at the same time it's got to deal with the heat.

同时还需要防止自己的头被烤熟了。

This is Africa. It's hot.

这是非洲，非常的热，

So what I want to share with you now

现在我要跟大家分享的

are some of the experiments that myself and my colleagues

是我自己和我的同事做过的一些实验

have used to investigate how dung beetles

我们研究了蜣螂

deal with these problems.

是如何处理这些问题的。

So watch this beetle,

看这些蜣螂，

and there's two things that I would like you to be aware of.

我希望你注意到两个细节。

The first is how it deals with this obstacle

一是它如何处理我们

that we've put in its way. See, look, it does a little dance,

放在路上的障碍物。看，像是跳舞一样，

and then it carries on in exactly the same direction

然后它继续照着它一开始的方向前进，

that it took in the first place.

分毫不差。

A little dance, and then heads off in a particular direction.

一小段舞蹈，然后又冲着一开始的方向。

So clearly this animal knows where it's going

非常明显这个小东西有方向感

and it knows where it wants to go,

而且知道要往哪里去。

and that's a very, very important thing,

这是非常、非常重要的一件事情

because if you think about it, you're at the dung pile,

你自己想想看，你站在粪堆上，

you've got this great big pie that you want to get away from everybody else,

你现在有了一个粪球，而你想要它离别的蜣螂远远的，

and the quickest way to do it is in a straight line.

最快的转移路线就是一条直线。

So we gave them some more tasks to deal with,

于是我们做了更多的实验，

and what we did here is we turned the world

我们把蜣螂脚下的地皮

under their feet. And watch its response.

挪了挪位置，然后看它的反应。

So this animal has actually had the whole world

现在蜣螂所在的一小块范围

turned under its feet. It's turned by 90 degrees.

已经被我们转了90度。

But it doesn't flinch. It knows exactly where it wants to go,

它毫不畏惧，它清楚知道要往哪里走，

and it heads off in that particular direction.

而且它转向了一个特定的方向。

So our next question then was,

我们第二个问题是

how are they doing this?

它们怎么做到的？

What are they doing? And there was a cue that was available to us.

它们做了什么？有一条可能的线索。

It was that every now and then they'd climb on top of the ball

它们经常需要爬到粪球的顶端

and they'd take a look at the world around them.

这样它们可以看到周边的环境。

And what do you think they could be looking at

这时候你可能会想它们爬上了粪球之后

as they climb on top of the ball?

能看到什么东西？

What are the obvious cues that this animal could use

周围有什么“标志性建筑”让蜣螂能够

to direct its movement? And the most obvious one

指引自己的方向？而最明显的地标

is to look at the sky, and so we thought,

应该就是天空了。我们接着想，

now what could they be looking at in the sky?

现在（大白天）它们看天上能看到什么？

And the obvious thing to look at is the sun.

最显眼的就是太阳。

So a classic experiment here,

于是我们做了一个经典实验，

in that what we did was we moved the sun.

我们移动了太阳的位置。

What we're going to do now is shade the sun with a board

我们现在用一块板把太阳遮起来

and then move the sun with a mirror

再用一块镜子把太阳

to a completely different position.

挪到另外一个位置。

And look at what the beetle does.

然后我们看这些蜣螂怎么办。

It does a little double dance,

它调整了一下，

and then it heads back in exactly the same direction

然后转到了跟原先的前进路线

it went in the first place.

完全相反的方向。

What happens now? So clearly they're looking at the sun.

这是怎么回事？这很明显的证明了它们靠太阳认路。

The sun is a very important cue in the sky for them.

对它们来说太阳是天上很重要的一个指引。

The thing is the sun is not always available to you,

可是是太阳并不是一直挂在天上，

because at sunset it disappears below the horizon.

日落之后太阳就在地平线以下了。

What is happening in the sky here

在日落之后天空中

is that there's a great big pattern of polarized light in the sky

充满了大量的偏振光

that you and I can't see. It's the way our eyes are built.

这是我们人类的眼睛所看不到的。

But the sun is at the horizon over here

现在太阳在远处的地平线上

and we know that when the sun is at the horizon,

我们知道太阳在地平线下时

say it's over on this side,

我们假设在这个位置

there is a north-south, a huge pathway across the sky

这是北极和南极，偏振光沿着这条长长的路线贯穿天空

of polarized light that we can't see

我们的眼睛看不到它们

that the beetles can see.

但是蜣螂可以看到。

So how do we test that? Well, that's easy.

我们怎么证明这点？其实不难，

What we do is we get a great big polarization filter,

我们找到一个很大的偏振光滤镜，

pop the beetle underneath it, and the filter is at right angles

把它罩在蜣螂上面，把偏振光滤镜调整到

to the polarization pattern of the sky.

跟大气中的偏振光对应的角度

The beetle comes out from underneath the filter

蜣螂从我们的滤镜下面出来了

and it does a right-hand turn,

右转了一下

because it comes back under the sky

因为它重新看到了

that it was originally orientated to

没有被过滤的天空

and then reorientates itself back

于是它就又可以把自己的路线

to the direction it was originally going in.

调整到最初的前进方向上。

So obviously beetles can see polarized light.

这个实验证明了蜣螂可以看到偏振光。

Okay, so what we've got so far is,

现在，让我们回顾一下，

what are beetles doing? They're rolling balls.

蜣螂做什么事情？它们滚粪球。

How are they doing it? Well, they're rolling them in a straight line.

怎么滚粪球？它们沿着直线滚。

How are they maintaining it in a particular straight line?

它们怎么能滚出一条直线来？

Well, they're looking at celestial cues in the sky,

它们通过天上的太阳和偏振光线索进行定位。

some of which you and I can't see.

有些线索我们人类看不见。

But how do they pick up those celestial cues?

但是它们是怎么感知到天上的各种天体信息的？

That was what was of interest to us next.

这是我们就接下来要关心的。

And it was this particular little behavior, the dance,

我们关心的就是这段舞蹈（调整方向的过程），

that we thought was important, because look,

我们相信这个行为很重要，你看

it takes a pause every now and then,

它每次都会停下来，调整一下

and then heads off in the direction that it wants to go in.

然后朝着它想去的方向推进。

So what are they doing when they do this dance?

所以问题是它们在跳舞（调整）的时候做了什么？

How far can we push them before they will reorientate themselves?

在它们重新调整方向之前我们能够误导它们多远？

And in this experiment here, what we did was we forced them

在这个实验中，我们铺了一段管道

into a channel, and you can see he wasn't

让蜣螂不知不觉的

particularly forced into this particular channel,

走入这个特殊的管道

and we gradually displaced the beetle by 180 degrees

这个管道一点一点的让蜣螂改变方向，

until this individual ends up going in exactly the opposite direction

最终让它转了180度的大弯

that it wanted to go in, in the first place.

跟它刚进管道时的方向恰恰相反。

And let's see what his reaction is

我们来看看它的反应：

as he's headed through 90 degrees here,

现在它跟原来的方向偏了90度，

and now he's going to -- when he ends up down here,

现在它正要——它在这里停了下来，

he's going to be 180 degrees in the wrong direction.

它已经跟原先的方向偏差了180度。

And see what his response is.

看它的反应

He does a little dance, he turns around,

它跳了一小段舞，它转了过来，

and heads back in this. He knows exactly where he's going.

它开始往回推。它清楚的知道自己在干嘛。

He knows exactly what the problem is,

它清楚的知道哪里出了问题，

and he knows exactly how to deal with it,

它也清楚的知道怎么处理这个问题。

and the dance is this transition behavior

而这种舞蹈本身就是调整自己的动作。

that allows them to reorientate themselves.

让它们可以重新确定方向。

So that's the dance, but after spending many years

这就是蜣螂的舞蹈，但是我们花了这么多年

sitting in the African bush watching dung beetles on nice hot days,

蹲在非洲那么热的灌木丛中观察蜣螂

we noticed that there was another behavior

我们除了发现蜣螂的舞蹈是用来调整方向

associated with the dance behavior.

我们还发现了舞蹈的另一个用途。

Every now and then, when they climb on top of the ball,

时不时的，每当它们爬上粪球的顶端时，

they wipe their face.

它们都会擦自己的脸。

And you see him do it again.

再看一次，

Now we thought, now what could be going on here?

现在我们想，它这是在干什么？

Clearly the ground is very hot, and when the ground is hot,

现在地面很烫，而当地表很烫的时候，

they dance more often, and when they do this particular dance,

它们跳舞就跳得频繁。当它们跳这种舞蹈时，

they wipe the bottom of their face.

它们会擦自己的脸的底部

And we thought that it could be a thermoregulatory behavior.

我们猜想这可能属于体温调节的行为。

We thought that maybe what they're doing is trying to

我们猜想它们之所以这么做是想要

get off the hot soil and also spitting onto their face

把脸上滚烫的沙子擦掉并涂点吐沫

to cool their head down.

在自己头上降温。

So what we did was design a couple of arenas.

于是我们设计了两个实验场。

one was hot, one was cold.

一个温度很高，一个温度不高。

We shaded this one. We left that one hot.

我们遮起来这一块地，另一块什么也没遮。

And then what we did was we filmed them with a thermal camera.

接下来我们用热成像摄像头去拍摄蜣螂。

So what you're looking at here is a heat image

你现在看到的是我们实验的热成像图

of the system, and what you can see here emerging

你可以注意到在图像中

from the poo is a cool dung ball.

粪球的温度很低。

So the truth is, if you look at the temperature over here,

所以事实上就是，当你从温度的角度来看

dung is cool. (Laughter)

便便太酷了（酷和冷都是“cool”）（观众笑）

So all we're interested in here is comparing the temperature

当然我们最感兴趣的还是比较地表的温度

of the beetle against the background.

和蜣螂的温度差异。

So the background here is around about 50 degrees centigrade.

地表的温度大概是50摄氏度左右，

The beetle itself and the ball are probably around about

蜣螂和粪球的温度大概处在

30 to 35 degrees centigrade,

30到35摄氏度这个范围。

so this is a great big ball of ice cream

所以对于正在穿越炎热的“非洲大草原”的

that this beetle is now transporting across the hot veld.

蜣螂而言，粪球就是个巨无霸冰淇淋。

It isn't climbing. It isn't dancing, because

它没有爬上粪球也没有跳舞，

its body temperature is actually relatively low.

因为它的温度已经相对较低了。

It's about the same as yours and mine.

它的体温跟你我都差不多。

And what's of interest here is that little brain is quite cool.

值得注意的是它的小脑袋温度非常的低。

But if we contrast now what happens in a hot environment,

但是如果同样的事情发生在炎热的环境中，

look at the temperature of the soil.

看看这边地表的温度，

It's up around 55 to 60 degrees centigrade.

大概在55到60摄氏度之间。

Watch how often the beetle dances.

注意看蜣螂开始频繁的跳舞。

And look at its front legs. They're roaringly hot.

注意它的前腿，非常的热。

So the ball leaves a little thermal shadow,

粪球提供了一个降温场所，

and the beetle climbs on top of the ball

我们认为蜣螂之所以爬上粪球，

and wipes its face, and all the time it's trying to cool itself down,

擦自己的脸是为了让自己凉快一些，

we think, and avoid the hot sand that it's walking across.

并把前进过程中沾上的热沙去掉。

And what we did then was put little boots on these legs,

然后我们给蜣螂穿上了特制的小鞋子，

because this was a way to test if the legs

希望搞清楚蜣螂是不是

were involved in sensing the temperature of the soil.

用它的前腿来检测地表的温度。

And if you look over here, with boots they climb onto the ball

看这里你能发现，穿了鞋子的蜣螂比没穿鞋子的

far less often when they had no boots on.

爬上粪球的次数要少了很多。

So we described these as cool boots.

我们叫这些小鞋子为“清凉靴”。

It was a dental compound that we used to make these boots.

鞋子的原料是从一个牙印胶膜上剪的，

And we also cooled down the dung ball, so we were able

我们还把它们的粪球放在冰箱里面冷冻，

to put the ball in the fridge, gave them a nice cool dung ball,

给蜣螂提供一个冰爽可口的冰淇淋粪球，

and they climbed onto that ball far less often

我们发现相比热腾腾的粪球，

than when they had a hot ball.

它们爬上粪球的次数少了很多。

So this is called stilting. It's a thermal behavior

这种手法叫“踩高跷”。这跟你我穿过沙滩时

that you and I do if we cross the beach,

避免脚被烫到的行为是类似的，

we jump onto a towel, somebody has this towel --

我们跳上一条毛巾，不知道谁的毛巾 ——

"Sorry, I've jumped onto your towel." --

“抱歉，我踩到了你的毛巾。”——

and then you scuttle across onto somebody else's towel,

然后你又跳到另一个人的毛巾上，

and that way you don't burn your feet.

这样你就不会烫到自己的脚了。

And that's exactly what the beetles are doing here.

蜣螂也是这么做的。

However, there's one more story I'd like to share with you,

我还有一个好玩的事情要跟你们分享，

and that's this particular species.

关于这个特别的品种。

It's from a genus called Pachysoma.

这个物种属于“Pachysoma”属。

There are 13 species in the genus, and they have

“Pachysoma”属包含13个不同的物种，

a particular behavior that I think you will find interesting.

它们有种行为很特别，我想你会很感兴趣。

This is a dung beetle. Watch what he's doing.

看这只蜣螂，注意看它在干嘛。

Can you spot the difference?

你看到不同了么？

They don't normally go this slowly. It's in slow motion.

它们运动的比看起来要快很多，现在是慢速播放。

but it's walking forwards,

它在向前走，

and it's actually taking a pellet of dry dung with it.

事实上它随身带了一个粪丸子。

This is a different species in the same genus

虽然这是同一属中不同的物种，

but exactly the same foraging behavior.

但是觅食行为都是完全一致的。

There's one more interesting aspect of this

这只蜣螂还有一个有意思的地方

dung beetle's behavior that we found quite fascinating,

就是它会建立巢穴并存储粮食，

and that's that it forages and provisions a nest.

这让我们觉得很神奇。

So watch this individual here, and what he's trying to do

注意看这只，它正打算

is set up a nest.

做一个窝。

And he doesn't like this first position,

然后它不满意它一开始选的地方，

but he comes up with a second position,

它找到了第二个地段

and about 50 minutes later, that nest is finished,

50分钟后，窝建好了。

and he heads off to forage and provision

然后它开始外出寻找食物

at a pile of dry dung pellets.

并囤积了大量的粪丸子。

And what I want you to notice is the outward path

我想让你注意的是它出去的路径

compared to the homeward path, and compare the two.

和回来的时候走的路径。对比一下。

And by and large, you'll see that the homeward path

从总体上看，你会意识到它回家的路线

is far more direct than the outward path.

要比外出的路线更加像是直线。

On the outward path, he's always on the lookout

当外出觅食时，它总是东张西望的

for a new blob of dung.

寻找新的便便。

On the way home, he knows where home is,

回家的路上，它知道家在哪里，

and he wants to go straight to it.

而且它想走直线回家。

The important thing here is that this is not a one-way trip,

这点很重要，与其它绝大多数蜣螂的单向旅程不同，

as in most dung beetles. The trip here is repeated

这只蜣螂的需要在食物来源

back and forth between a provisioning site and a nest site.

和自己的巢穴之间反复来回。

And watch, you're going to see

注意看，另一场发生在南非的

another South African crime taking place right now. (Laughter)

犯罪行为正在进行。（观众笑）

And his neighbor steals one of his dung pellets.

它的邻居偷了它的一个粪丸子。

So what we're looking at here

我们刚才观察到的行为

is a behavior called path integration.

称为“路径整合（path integration）”。

And what's taking place is that the beetle

这个的意思是说蜣螂

has got a home spot, it goes out on a convoluted path

知道巢穴的位置，它沿着弯弯绕绕的路线

looking for food, and then when it finds food,

寻找食物，一旦它找到了食物，

it heads straight home. It knows exactly where its home is.

它沿着直线返回巢穴。它清楚的知道家在哪里。

Now there's two ways it could be doing that,

有两种方式可以做到这一点，

and we can test that by displacing the beetle

我们可以通过挪动蜣螂巢穴位置的办法

to a new position when it's at the foraging site.

来确定它使用的是哪种方式。

If it's using landmarks, it will find its home.

如果它使用的是地标信息，那么它会找到自己的巢穴；

If it is using something called path integration,

反之如果使用的是路径整合，

it will not find its home. It will arrive at the wrong spot,

它就会找不到，跑到一个错误的位置去。

and what it's doing here if it's using path integration

在这里使用“路径整合”的意思是指

is it's counting its steps or measuring the distance out in this direction.

它记得走过的步数或走过的距离。

It knows the bearing home, and it knows it should be in that direction.

它知道家的方向，知道应该往那里走。

If you displace it, it ends up in the wrong place.

如果巢穴被挪动，它将会走到错误的地方。

So let's see what happens when we put this beetle

现在我们来看看这个蜣螂

to the test with a similar experiment.

在相似的实验中如何反应。

So here's our cunning experimenter.

这就是我们狡猾的实验员

He displaces the beetle,

它转移了蜣螂，

and now we have to see what is going to take place.

我们看看接下来会发生什么

What we've got is a burrow. That's where the forage was.

这是一个巢穴，食物就放在里面。

The forage has been displaced to a new position.

食物被移动到了一个新的位置

If he's using landmark orientation,

如果它使用的地标导向

he should be able to find the burrow,

它应该可以找到巢穴

because he'll be able to recognize the landmarks around it.

因为它能够识别洞穴周围的地标

If he's using path integration,

如果它使用的是路径整合

then it should end up in the wrong spot over here.

它应该跑到一个错误的地方去

So let's watch what happens

现在让我们来考验一下蜣螂

when we put the beetle through the whole test.

看看会发生哪种情况。

So there he is there.

现在它跑到了那里

He's about to head home, and look what happens.

它本打算冲着巢穴的方向，但是看看结果。

Shame.

丢人啦。

It hasn't a clue.

它没有头绪。

It starts to search for its house in the right distance

它开始寻找巢穴的地点跟食物来源的相对距离是正确的

away from the food, but it is clearly completely lost.

但是显然它已经彻底迷路了。

So we know now that this animal uses path integration

现在我们知道这种蜣螂是通过路径整合

to find its way around, and the callous experimenter

来找到回家的路，但是我们无情的实验员

leads it top left and leaves it. (Laughter)

把它骗到了左上角然后抛弃了它。（观众笑）

So what we're looking at here are a group of animals

所以我们现在看到的这些动物

that use a compass, and they use the sun as a compass

它们会辨方向，它们使用太阳作为自己的指南针

to find their way around,

来寻找它们的路，

and they have some sort of system

它们还拥有某种形式上的

for measuring that distance,

距离测算系统

and we know that these species here actually

我们知道这些动物能够记住自己走过的步数

count the steps. That's what they use as an odometer,

它们用步数统计作为自己的里程表

a step-counting system, to find their way back home.

来找到它们回家的路。

We don't know yet what dung beetles use.

我们还不知道蜣郎是怎么做到的。

So what have we learned from these animals

我们从这种动物脑袋只有米粒那么大的

with a brain that's the size of a grain of rice?

动物身上能够学习到什么？

Well, we know that they can roll balls in a straight line

嗯，我们知道它们能借助天空中的天体线索

using celestial cues.

沿直线推球

We know that the dance behavior is an orientation behavior

我们知道它们的舞蹈是一种定向行为

and it's also a thermoregulation behavior,

也是一种温度控制行为

and we also know that they use a path integration system

我们还知道它们使用路径整合系统

for finding their way home.

来找到它们回家的路。

So for a small animal dealing with a fairly revolting substance

所以，从这种成天跟便便打交道的小动物身上

we can actually learn an awful lot from these things

我们可以学习到很多令人敬畏的技能

doing behaviors that you and I couldn't possibly do.

这些技能是你我都做不到的。

Thank you. (Applause)

谢谢大家。（鼓掌）