评论
打印
Ask any casual science enthusiast what animal group has more species than any other, and they'll probably say beetles.
随便问一个科学爱好者哪个动物群的物种最多，他们可能会告诉你，是甲虫。
And there are a ton of beetle species—more than 350 thousand, in fact.
世界上甲虫种类超级多—事实上有超过35万种。
That's about 22% of all species that we've identified and named so far, including stuff like bacteria.
到目前为止，在我们已经确认并命名的物种中（包括细菌），其中甲虫种类约占22%。
But some scientists think beetles' time at number one should come to an end.
但是一些科学家认为甲虫占第一的时代应该结束了。
Other animal groups, they say, may be more deserving of the title of "most species".
他们表示其他动物群，可能更配得上“大多数物种”的称号。
Though it's tough to say which group that actually is, and it's not just about knowing for curiosity's sake.
虽然很难说到底是哪个群体，但这并不仅仅是出于好奇。
Having good estimates of how many species of beetle, plant, or bird
准确估计甲虫、植物或鸟类的种类数量，
there are is vital to tracking how those numbers are changing, and what we have to do to preserve them.
对于追踪这些数字如何变化，以及我们必须做些什么来保护它们是至关重要的。
It's hard to actually pin down how many species there are for a couple of different reasons.
由于几个不同的原因，很难确定到底有多少种。
One is that species estimates are based on the number of species we currently know about,
一个是物种估计是基于我们目前知道的物种数量，
and we're not familiar with an equal proportion of every group of animals.
并且我们对每种动物群的平均比例并不熟悉。
It depends on how interested we are in them and how easy they are to find.
这取决于我们对它们的兴趣，以及找到它们的困难程度。
Beetles in particular were a popular collector's item with old-timey naturalists, who gathered them for their exciting array of colors.
甲虫尤其受旧时代博物学家的欢迎，他们收集甲虫是因为甲虫那令人兴奋的色彩组合。
And that interest meant there was ample funding and opportunity to go look for more beetles.
这种兴趣意味着有充足的资金和机会去寻找更多的甲虫。
Meanwhile, less charismatic animals, or ones that were smaller and harder to count, missed out—
同时，那些不太有魅力的动物，或者那些体型较小、难以计数的动物，都被漏掉了——
Animals like Hymenoptera, the group of insects that includes sawflies, wasps, bees, and ants.
比如膜翅目类，包括昆虫、锯蝇、黄蜂、蜜蜂和蚂蚁。
A 2018 paper published in the journal BMC Ecology argued that there are more species of hymenopterans than anything else,
2018年出版于《BMC Ecology》的一篇论文称膜翅目昆虫的种类比其他任何种类都多，
thanks in large part to parasitoid wasps. And if you're thinking of the yellowjackets in your garden, think again.
这在很大程度上要归功于寄生性黄蜂。如果你想到了你花园里的黄夹克，再想想吧。
These wasps can be barely bigger than a grain of sand and spend most of their life cycle inside other insects,
这些黄蜂比一粒沙子大不了多少，它们的大部分生命周期都在其他昆虫体内度过，
making them very easy to miss.
因此很容易被忽视。
Parasitoid wasps target pretty much all insects, including ones that live in the ocean, in the Arctic, and deep down in the soil.
拟寄生物黄蜂的目标几乎是所有的昆虫，包括生活在海洋、北极和土壤深处的昆虫。
And scientists think that these wasps are pretty specialized, meaning each species only targets a specific type of host.
科学家认为这些黄蜂非常特殊，这意味着每个物种只针对一种特定的宿主。
So according to the 2018 study, every insect, including all those beetles,
根据2018年的研究，每种昆虫，包括那些甲虫，
might have not just one but potentially multiple species of parasitic wasp hunting them down.
可能不止一种而是可能有多种寄生蜂在追捕它们。
Also, insects have multiple life stages, and different wasps can target both the larval and adult forms.
此外，昆虫有多个生命阶段，不同的黄蜂可以同时针对以幼虫和成虫为目标。
So two wasps for every beetle? I mean, you do the math.
那么每两只甲虫对应两只黄蜂？我是说，你自己算算。
That's not even counting parasitoids that target other parasitoids or ones that go for non-insect arthropods, like spiders.
这还不包括以其他拟寄生物为目标的拟寄生物或以非昆虫节肢动物为目标的拟寄生物，比如蜘蛛。
And it's not just one study making this claim.
并不是只有一项研究得出了这样的结论。
Studies of sand dunes in California and insects in Canada estimate that
对加利福尼亚沙丘和加拿大昆虫的研究估计
hymenopteran species outnumber beetles by about two and a half times in that particular habitat.
在这个特定的栖息地，膜翅目昆虫的数量是甲虫的2.5倍。
Now, if hymenopterans are not the most speciose animal group—
现在，如果膜翅目昆虫不是物种最多的动物群体——
that's the technical term for having a lot of species—it's probably still some sort of parasite.
这是一个专业术语，指的是有很多物种——它可能仍然是某种寄生虫。
And that's because parasitism is really popular in the natural world,
这是因为寄生在自然界中非常普遍，
evolving more than 200 separate times in 15 different groups of animals.
在15个不同的动物群体中进化了200多次。
And it makes sense! Hosts are both food and shelter rolled into one.
这是有道理的！宿主既是食物又是庇护所。
That makes nematodes, or roundworms, another contender for the most species-rich group.
这使得线虫或蛔虫成为物种最丰富群体的另一个竞争者。
Not all nematodes are parasites, but many are and they target not just insects, but also other animals and plants.
并不是所有的线虫都是寄生虫，但是大部分是都是，并且它们的目标不仅昆虫，还有其他动物和植物。
One 1993 study estimated there may be well over a million nematode species,
一项1993年的研究估计可能有超过100万种的线虫物种，
though other estimates have varied wildly because they're so understudied.
尽管其他的估计有很大的差异，因为关于它们的研究太少了。
Another paper from 2008 suggested that there may be between 75,000 and 300,000 species of nematodes parasitizing vertebrates alone.
另一项2008年的论文表明仅寄生线虫的脊椎动物就有75,000到300,000种。
And nematodes have been found everywhere, including sediments deep down on the ocean floor.
处都能找到线虫，包括海底深处的沉积物。
There's probably nematodes in places humans have never even been yet.
在人类从未到过的地方可能有线虫。
Which is an important point: species estimates rely on what we can find, which means they rely on where humans can go.
这一点很重要：物种估测依赖于我们能找到什么，这意味着它们依赖于人类能去哪里。
Now, you may have noticed that we're comparing nematodes,
现在，你可能已经注意到，我们正在将线虫，
which are an entire phylum of worms, to wasps and beetles, which according to the tree of life are technically orders.
这是一个完整的蠕虫门，与黄蜂和甲虫（根据生命之树，它们是学术目）进行比较。
You know, kingdom, phylum, class, order.
分类有四种：王国、门、类、目。
But even if you compare whole phyla, nematodes could still win out over arthropods, the phylum that contains wasps and beetles.
但是即便及比较整个类群，线虫仍然可能战胜节肢动物，节肢动物门中包含了黄蜂和甲虫。
We think there's roughly a million of each, but there's so much variation in those estimates that it's tough to call.
我们认为每一种大约有100万个，但是这些估计有太多的变量，很难预测。
And we don't assign those groups—phyla, classes or orders—based on how big they are, but that's a whole other story.
我们不会根据它们的大小来分配它们——门、类或目，但那是另一回事了。
And then there's the question of charisma, which could explain why Diptera, the order that includes true flies, have been overlooked.
然后是魅力的问题，这可以解释为什么双翅目，包括苍蝇的目会被忽视了。
They might grab your attention when they're buzzing around your living room, but there aren't many people who'd say they… like flies.
它们在你的房间里嗡嗡飞的时候，你可能会注意到它们，但是没有多少人会说他们喜欢苍蝇。
Not like people like beetles. But when scientists do get to studying them, they find a surprising number of species.
不像是有人喜欢甲虫。但当科学家开始研究它们的时候，他们发现它们种类惊人。
Like a study from 2018 that found more than 4000 species of true flies in a four-hectare patch of Costa Rican rainforest.
2018年的一项研究发现在哥斯达黎加的一片四公顷的雨林中，苍蝇的种类超过4000种。
Current estimates put Diptera at more than a million species, easily surpassing beetle numbers.
目前估计双翅目有超过100万种，很容易超过甲虫的数量。
There's that million number again … I mean, we told you it was tough to call.
又有百万这个数字了…
Flies can live almost anywhere on land and, as larvae, can feed on everything from plant nectar to vertebrate blood.
苍蝇几乎可以生活在陆地上的任何地方，作为幼虫，它可以以任何东西为食，从植物花蜜到脊椎动物的血液。
And that's important too: for a group of animals to stand a chance at being the most speciose,
这一点也很重要：一群动物要想有机会成为最丰富的物种，
it has to show variety in where it lives, what it eats, and how it survives in general.
就必须在生活的地方、吃的东西上以及如何生存等方面表现出多样性。
And that could mean making yourself comfortable inside a host like a parasite does,
这可能意味着你要像寄生虫一样舒服地待在宿主体内，
or being able to find homes in some of the most remote places on Earth.
或者能够在地球上一些最偏远的地方找到家。
But, if there's anything we've learned from trying to count all of the animals,
但是，如果说我们从总计所有动物这方面学到了什么的话，
it's that what's right in front of us isn't always a good indicator.
那就是我们面前的东西并不总是一个好的指示物。
If we want to know what's out there, we've got to go look for it.
如果我们想知道外边有什么，我们就要自己去查看。
Thank you for watching this episode of SciShow.
感谢收看本期节目。
If you want to help support the channel, you can do so over on Patreon.
如果你想帮助支持我们频道，你可以去Patreon上看看。
We've got the best community of supporters around, and you can meet and chat with them—
我们有最好的社区支持者，大家可以见面聊天——
and some of our team—over on our patron-only Discord.
也可以和我们的团队联系—进入会员专区即可。
If you want to get started, head over to patreon.com/scishow.
如果想加入我们，请登录patreon.com/scishow。
