Jaap de Roode: How butterflies self-medicate

翻译人员: Coco Shen 校对人员: Daohan Xiong

So infectious diseases, right?

说到传染病

Infectious diseases are still the main cause

传染病仍然是全球人类

of human suffering and death around the world.

生病和死亡的主因。

Every year, millions of people die of diseases such as T.B., malaria, HIV,

每年，数以万计的人们死于

around the world and even in the United States.

肺结核、疟疾、以及艾滋病

Every year, thousands of Americans die of seasonal flu.

甚至在美国， 每年都有成千上万的人因流感致命。

Now of course, humans, we are creative. Right?

人类不是很有创意吗？

We have come up with ways to protect ourselves against these diseases.

我们想出不少办法保护自己，

We have drugs and vaccines.

用药物和疫苗抵抗传染病。

And we're conscious -- we learn from our experiences

我们十分谨慎地总结经验

and come up with creative solutions.

得出创新的解决办法。

We used to think we're alone in this, but now we know we're not.

我们以为只有人类才懂医学

We're not the only medical doctors.

但是其实不然

Now we know that there's a lot of animals out there that can do it too.

许多其他动物也有类似的机制

Most famous, perhaps, chimpanzees.

最典型的是大猩猩

Not so much different from us,

和人类差不多

they can use plants to treat their intestinal parasites.

它们会利用植物清理肠道寄生虫

But the last few decades have shown us that other animals can do it too:

几十年的研究发现很多动物都会保护自己

elephants, porcupines, sheep, goats, you name it.

大象、豪猪、绵羊、山羊…数不胜数

And even more interesting than that is that recent discoveries are telling us

更有趣的是，最近的研究发现

that insects and other little animals with smaller brains can use medication too.

昆虫和其他小型生物也懂得医疗

The problem with infectious diseases, as we all know,

我们都知道传染病的病原体

is that pathogens continue to evolve,

不断演化。

and a lot of the drugs that we have developed

我们过去开发的一些药物

are losing their efficacy.

正在逐渐失效

And therefore, there is this great need to find new ways to discover drugs

因此我们更需要不断开发新药物

that we can use against our diseases.

来应对不断变化的病原体。

Now, I think that we should look at these animals,

现在我们来研究一下这些动物

and we can learn from them how to treat our own diseases.

看看从它们身上哪些是值得借鉴的

作为生物学家， 我研究了十年帝王斑蝶

As a biologist, I have been studying monarch butterflies for the last 10 years.

Now, monarchs are extremely famous for their spectacular migrations

帝王斑蝶以它们壮观的迁徙而闻名

from the U.S. and Canada down to Mexico every year,

每年不计其数的帝王斑蝶来到一起

where millions of them come together,

从美国和加拿大迁徙到墨西哥

but it's not why I started studying them.

但这并非我研究它们的原因

I study monarchs because they get sick.

我研究它们是因为它们会生病

They get sick like you. They get sick like me.

就像在座的你我

And I think what they do can tell us a lot about drugs

我认为我们可以从它们身上得到启发

that we can develop for humans.

来开发适用于人类的药物

Now, the parasites that monarchs get infected with

帝王斑蝶身上的寄生虫叫做

are called ophryocystis elektroscirrha -- a mouthful.

ophryocystis elektroscirrha

What they do is they produce spores,

这些寄生虫在蝶身上

millions of spores on the outside of the butterfly

引起大量的孢子

that are shown as little specks in between the scales of the butterfly.

可以从鳞片夹缝中看见这些细小的斑点

And this is really detrimental to the monarch.

它们威胁着帝王斑蝶的健康

It shortens their lifespan,

缩短了它们的寿命

it reduces their ability to fly,

影响它们的飞行能力

it can even kill them before they're even adults.

甚至导致它们还没成年就死亡。

Very detrimental parasite.

这种寄生虫非常致命。

As part of my job, I spend a lot of time in the greenhouse growing plants,

我工作时经常需要在温室里种植植物

and the reason for this is that monarchs are extremely picky eaters.

因为帝王斑蝶十分挑食

They only eat milkweed as larvae.

它们只吃乳草的幼草

Luckily, there are several species of milkweed that they can use,

幸好我找到了几种它们食用的乳草。

and all these milkweeds have cardenolides in them.

这些乳草中含有卡烯內酯，

These are chemicals that are toxic.

是一种具有毒性的物质

They're toxic to most animals, but not to monarchs.

奇怪的是它对帝王斑蝶无害

In fact, monarchs can take up the chemicals,

帝王斑蝶吸收了这种毒素

put it in their own bodies, and it makes them toxic

携带这种毒素在体内

against their predators, such as birds.

用于对付诸如鸟类的天敌

And what they do, then, is advertise this toxicity

它们用身上鲜豔的黄黑白斑纹

through their beautiful warning colorations

来广告自己的毒性。

with this orange, black and white.

一种自然警告标志。

So what I did during my job is grow plants in the greenhouse,

当我在温室善尽己责，

different ones, different milkweeds.

种植不同乳草时，

Some were toxic, including the tropical milkweed,

某些毒性很高，像是热带乳草，

with very high concentrations of these cardenolides.

有大量的強心甾 (cardenolides)，

And some were not toxic.

某些却没有毒素。

And then I fed them to monarchs.

在我喂食帝王斑蝶时，

Some of the monarchs were healthy. They had no disease.

某些斑蝶没有染病，很健康。

But some of the monarchs were sick,

某些斑蝶则生着病，

and what I found is that some of these milkweeds are medicinal,

我发现某些乳草有药效，

meaning they reduce the disease symptoms in the monarch butterflies,

有效减低帝王斑蝶的症状

meaning these monarchs can live longer when they are infected

只要它们食用这些药草，

when feeding on these medicinal plants.

就可以延长自己的性命。

And when I found this, I had this idea,

当我发现的时候，

我有了一很多人觉得很疯狂的想法

and a lot of people said it was a crazy idea,

but I thought, what if monarchs can use this?

我想，如果帝王斑蝶可以应用呢？

What if they can use these plants as their own form of medicine?

如果它们可以把这些乳草当作药物呢？

What if they can act as medical doctors?

如果它们可以为自己开药房呢？

So my team and I started doing experiments.

我们的团队开始实验，

In the first types of experiments,

在第一类实验里，

we had caterpillars, and gave them a choice:

我们给幼虫两种选择：

medicinal milkweed versus non-medicinal milkweed.

有药性的乳草和没有药性的乳草。

And then we measured how much they ate of each species over their lifetime.

然后测量它们一生各自吃了多少。

And the result, as so often in science, was boring:

就像大部分的科学研究结果一样， 答案很无聊：

Fifty percent of their food was medicinal. Fifty percent was not.

有药性和没有药性的各半。

These caterpillars didn't do anything for their own welfare.

这些幼虫没有为自己做出有利的选择。

So then we moved on to adult butterflies,

于是我们转为研究成蝶。

and we started asking the question

我们想

whether it's the mothers that can medicate their offspring.

母蝶会对自己的幼虫用药吗？

Can the mothers lay their eggs on medicinal milkweed

它们会把卵产在有药的乳草上，

that will make their future offspring less sick?

减轻幼虫的症状？

We have done these experiments now over several years,

我们复制这个实验多年，

and always get the same results.

得到一样的结果。

What we do is we put a monarch in a big cage,

我们把帝王斑蝶放进大笼子里，

a medicinal plant on one side, a non-medicinal plant on the other side,

一边的乳草是有药性的，一边没有，

and then we measure the number of eggs that the monarchs lay on each plant.

然后测量它们在两种乳草上的产卵数，

And what we find when we do that is always the same.

获得的结果是一致的。

What we find is that the monarchs strongly prefer the medicinal milkweed.

我们发现帝王斑蝶偏好药性乳草。

In other words, what these females are doing

换句话说

is they're laying 68 percent of their eggs in the medicinal milkweed.

雌蝶把 68％ 的卵产在药性乳草上。

Intriguingly, what they do is they actually transmit the parasites

事实上，在它们产卵的时候，

when they're laying the eggs.

也不可避免的

They cannot prevent this.

传播了寄生虫。

They can also not medicate themselves.

它们不能治疗自己。

But what these experiments tell us

但这个实验告诉我们

is that these monarchs, these mothers, can lay their eggs on medicinal milkweed

帝王斑蝶把卵产在有药性的乳草上，

that will make their future offspring less sick.

减轻幼虫的病况。

Now, this is a really important discovery, I think,

这个发现很重要。

not just because it tells us something cool about nature,

不只是因为它显示了大自然的奥妙，

but also because it may tell us something more about how we should find drugs.

更提醒我们应该如何开发药物。

Now, these are animals that are very small

这些动物都很小，

and we tend to think of them as very simple.

我们曾经觉得它们构造单纯，

They have tiny little brains,

它们的大脑很小，

yet they can do this very sophisticated medication.

但它们却懂得利用自然药草。

Now, we know that even today, most of our drugs

直至今日，

derive from natural products, including plants,

我们从自然中提取药物，包括植物，

and in indigenous cultures,

在一些原始文化中，

traditional healers often look at animals to find new drugs.

传统疗法时常借镜动物来找新药方。

In this way, elephants have told us how to treat stomach upset,

大象教我们如何治疗肠胃不适，

and porcupines have told people how to treat bloody diarrhea.

刺猬教我们如何处理腹泻。

What I think is important, though, is to move beyond

我想，最重要的是，

these large-brained mammals and give these guys more credit,

除了那些大脑发达的哺乳类动物外，

these simple animals, these insects that we tend to think of

我们也应该更加注重

as very, very simple with tiny little brains.

那些构造简单的动物、昆虫。

The discovery that these animals can also use medication

发现这些动物懂得用药，

opens up completely new avenues,

让我们进入全新领域。

and I think that maybe one day, we will be treating human diseases

也许有一天，

我们会用蝴蝶找到的药物来治疗人类，

with drugs that were first discovered by butterflies,

and I think that is an amazing opportunity worth pursuing.

我想这个机会是值得把握的。

Thank you so much.

谢谢各位。

(Applause)

（掌声）