You've probably heard of leafcutter ants or have even seen them yourself.

您可能聽說過切葉蟻，甚至親眼見過。

Lines of ants marching with pieces of leaves in their mandibles.

成排的螞蟻用下顎夾著樹葉行進。

But if you look closely, there's something else weird going on here.

但如果你仔細觀察，就會發現這裡還有一些奇怪的事情。

On many of the leaves, smaller ants are hitching a ride.

在許多樹葉上，體型較小的螞蟻正在搭便車。

At first glance, this looks like the ants could just be confused, getting tangled up in the commotion and getting accidentally carried away.

乍一看，螞蟻們可能只是被騷亂所迷惑，不小心被捲了進去。

But this is no accident.

但這絕非偶然。

These ants are performing a very important job.

這些螞蟻正在執行一項非常重要的工作。

They're acting as sentinels, protectors of the leaf carrying ants, defending them against a devastating enemy, phorid flies.

它們像哨兵一樣保護著運葉蟻，抵禦著毀滅性的敵人--噬蠅。

These parasitic flies are trying to inject their eggs into the ant's body, where the larva will eat the ant from the inside out.

這些寄生蠅正試圖將它們的卵注入螞蟻的體內，幼蟲會從裡到外吃掉螞蟻。

So these smaller ants known as minims will ride the leaves and ward off any attack.

是以，這些被稱為 "小螞蟻 "的較小螞蟻會騎在樹葉上，抵禦任何攻擊。

This is the moment I realized the extent of the war being waged on the forest floor and realized that leafcutter ants are so much more than a mindless foliage carrying conveyor belt.

此時此刻，我才意識到森林地面上的戰爭有多麼慘烈，才意識到切葉蟻不僅僅是一條無意識的樹葉輸送帶。

The highway of leaves is one small part of an incredibly intricate and efficient society.

樹葉公路只是這個複雜而高效的社會的一小部分。

And the size and morphology discrepancy between the different ants only gets more extreme.

而且，不同螞蟻之間的體型和形態差異只會越來越大。

Not only are there the minims, the tiny ones, and the mediae foragers, but there are also these absolute units called the majors and super majors, who are absolutely giant compared to the rest.

不僅有 "小不點"、"小不點 "和 "媒介覓食者"，還有被稱為 "大塊頭 "和 "超級大塊頭 "的絕對組織、部門，他們與其他人相比絕對是龐然大物。

Clearly the ants in these colonies are extremely diverse and extremely specialized, but why?

顯然，這些蟻群中的螞蟻種類繁多，而且非常專業化，但為什麼會這樣呢？

Why is there so many different types of ants within one colony and so much division of labor?

為什麼一個蟻群中會有這麼多不同類型的螞蟻，而且分工如此細緻？

Because a colony needs to harvest and process an enormous amount of plant material, and that takes a lot of teamwork.

因為殖民地需要收穫和處理大量的植物材料，而這需要大量的團隊合作。

Leafcutters are the most prolific herbivores in the neotropical rainforest, accounting for about 25% of all herbivory.

切葉蟲是新熱帶雨林中最多的食草動物，約佔所有食草動物的 25%。

Mature Atta-Columbica colonies harvest between 85 kilograms and 470 kilograms total plant biomass per colony per year.

成熟的 Atta-Columbica 群落每年每個群落收穫的植物生物量總量在 85 千克到 470 千克之間。

Collecting all this material and defending those who do it is complicated enough, but there's an even higher goal here beyond collecting leaves, one unifying purpose that is only possible with tons of cooperation and division of labor among millions of individuals, and that is farming.

收集所有這些材料並保護那些從事這些工作的人已經夠複雜了，但這裡還有一個比收集樹葉更高的目標，一個只有在數百萬人之間進行大量合作和分工才能實現的統一目標，那就是耕種。

These little guys are farmers.

這些小傢伙都是農民。

This weird pile that the ants are tending to is their life-sustaining fungus crop.

螞蟻們正在打理的這堆奇怪的東西就是它們賴以生存的菌類作物。

The leaves they so dutifully carry back to the nest aren't their food.

它們盡職盡責搬回巢穴的樹葉並不是它們的食物。

They're the substrate for the fungus crop.

它們是真菌作物的基質。

The fungus is their food.

真菌是它們的食物。

Leafcutter ants are one of only a few animals that have mastered the art of deliberate and methodical agriculture, and they figured it out 60 million years before we did.

切葉蟻是僅有的幾種掌握了深思熟慮、有條不紊的農業藝術的動物之一，它們比我們早 6000 萬年就發現了這一點。

But how does an animal so small figure out something so complex?

但是，這麼小的動物是如何弄清如此複雜的事情的呢？

And how do all of the ants know exactly what job they need to carry out?

那麼，所有的螞蟻又是如何準確地知道它們需要執行什麼任務的呢？

And what about this delicate division of labor allows these ants to transcend what almost any other creature on Earth is capable of?

這種微妙的分工是如何讓這些螞蟻超越地球上幾乎所有其他生物的能力的呢？

There are 55 species of fungus-growing leafcutter ants belonging to three genera, Atta, Acromyrmex, and Amoymyrmex, within the tribe Atini.

蟻族中有 55 種生長真菌的食葉蟻，分屬 Atta、Acromyrmex 和 Amoymyrmex 三個屬。

The Acromyrmex and Amoymyrmex have colonies that range in the thousands, but the Atta is the genera with colonies that number in the millions, up to 8 million workers in some species.

Acromyrmex屬和Amoymyrmex屬的蟻群數量在數千只左右，但Atta屬的蟻群數量高達數百萬只，有些種類的蟻群數量甚至高達800萬隻。

Each gigantic Atta colony usually consists of just one mother queen, who is the exclusive reproductive individual, and millions of non-reproductive workers of different shapes and sizes, which are all her daughters.

每個巨大的雅塔蜂群通常只有一個母蜂王，她是唯一的生殖個體，還有數百萬個不同形狀和大小的非生殖工蜂，它們都是母蜂王的女兒。

And there are some reproductive winged males who leave the colony.

也有一些會繁殖的長著翅膀的雄性離開了蟻群。

How does one mother create such a diverse offspring?

一位母親如何創造出如此多樣化的後代？

For us, it would be like having one kid that's two feet tall, and another that's 18 feet tall.

對我們來說，這就好比一個孩子身高兩英尺，另一個孩子身高 18 英尺。

One explanation might be revealed by looking at the queen before the colony is even born.

一種解釋可能是，在蜂群出生之前就觀察蜂王。

Each year, colonies produce young reproductive females and males, which both have wings.

每年，群落都會產生可繁殖的雌性和雄性幼鳥，它們都有翅膀。

Then on one autumn night, every single flying male and new queen from every single colony within a species in the region takes flight in unison.

然後，在一個秋夜，該地區同一物種的每一個群落中的每一隻雄蜂和新蜂王都會齊刷刷地飛起來。

Scientists think this synchronized flight takes place based on environmental cues like temperature, humidity, and daylight hours, along with pheromones the males emit once airborne.

科學家們認為，這種同步飛行是根據溫度、溼度和日照時間等環境線索，以及雄性在空中釋放的資訊素進行的。

Then once millions of males and females are in the air, Atta mating takes place high in the atmosphere.

一旦數百萬只雄鳥和雌鳥飛到空中，Atta 就會在高空交配。

It's so high and so elusive that it has still never been directly observed.

它如此之高，如此難以捉摸，以至於至今仍未被直接觀測到。

But from what scientists do know from genetic analysis, this is unlike the mating we're used to hearing about.

但根據科學家從基因分析中瞭解到的情況，這與我們習以為常的交配不同。

Each queen is inseminated by three to eight different males, meaning her offspring will have several different fathers in a process called obligate multiple mating.

每隻蜂后都要接受三到八隻不同雄蜂的授精，這意味著它的後代會有幾個不同的父親，這一過程被稱為強制性多配偶交配。

This is kind of unusual to say the least.

至少可以說，這有點不尋常。

So what's the reason for so many different baby daddies all at once?

那麼，一下子有這麼多不同的孩子爸爸是什麼原因呢？

Having offspring with multiple fathers gives the brood more genetic diversity, and more genetic diversity provides resistance to disease.

有多個父親的後代會使雛鳥的遺傳多樣性更多，而遺傳多樣性越多，抗病能力就越強。

And in a colony of millions who live in close quarters, that is pretty crucial.

在數百萬人的聚居地裡，這一點至關重要。

And getting that much sperm all at once might be the only way she can keep having babies for her 10 to 20 year lifespan.

而一下子獲得這麼多精子，可能是她在 10 到 20 年的壽命中能繼續生孩子的唯一方法。

Atta cephalotes queens are among the longest lived insects.

Atta cephalotes 皇后是壽命最長的昆蟲之一。

She only gets inseminated this one time, and then stores the sperm cells in her spermatheca, her internal sperm bank.

它只接受這一次人工授精，然後將精子細胞儲存在精巢，也就是它體內的精子庫中。

But the final reason could be the explanation for how she has so many different types of offspring.

但最後一個原因可能是她為什麼會有這麼多不同類型的後代。

Having lots of different dads gives a much bigger range of phenotypic differences, which could lead to the big range of different sizes.

有許多不同的父親，表型差異的範圍就會大得多，這可能會導致不同體型的巨大差異。

But how the queen ant can ensure that she mates with the right males to give some gigantic babies, some tiny babies, and everything in between, we still don't know.

但是，蟻后如何才能確保與合適的雄蟻交配，生出巨大的孩子、小巧的孩子，以及介於兩者之間的所有孩子，我們仍然不得而知。

So this might partially explain how such morphological differences are possible in a single colony.

是以，這或許可以部分解釋為什麼在一個菌落中會出現如此大的形態差異。

But what's the evolutionary purpose of creating such wildly different babies?

但是，在進化過程中，製造出如此千差萬別的嬰兒的目的是什麼呢？

And what role do each of these morphs play?

這些形態各自扮演著什麼角色？

To find out, let's go back to the new queen to see how her incredible queendom fully develops.

為了一探究竟，讓我們回到新王后身邊，看看她不可思議的王后生涯是如何全面發展的。

Before she departed on her mating flight, the new Atta queen packed a small amount of fungus in her mouth.

在開始交配飛行之前，新的 Atta 皇后在嘴裡含了少量真菌。

This will be essential in starting her new colony.

這對她建立新的殖民地至關重要。

Once she is inseminated to her satisfaction, the queen lands on the ground and sheds her wings.

一旦受精成功，蟻后就會降落到地面上，然後脫下翅膀。

Here, she will excavate a nest chamber in the soil.

在這裡，它將在土壤中挖掘出一個巢室。

Once inside, she spits out the fungus she's been storing and feeds it with the first few eggs she lays.

一旦進入體內，它就會吐出儲存的真菌，並用產下的前幾枚卵餵養真菌。

Within three days, the mycelia have begun to grow.

三天內，菌絲開始生長。

For now, the queen cultivates the fungus garden herself.

現在，王后親自栽培菌類花園。

But soon, she will need help.

但很快，她就需要幫助了。

And for this reason, the first batch of offspring she will have are the minims, the smallest ants of the colony.

是以，它的第一批後代就是最小的螞蟻，也就是蟻群中最小的螞蟻。

These smallest of ants take over, tending to the fungus.

這些最小的螞蟻會接替它們，照顧真菌。

Their small size allows them to maneuver easily within the delicate fungal structures, removing waste and secreting bodily fluids to keep it healthy.

它們體型小巧，可以輕鬆地在脆弱的真菌結構內活動，清除廢物，分泌體液，以保持真菌的健康。

Soon, slightly larger ants hatch, and they are just big enough to leave the nest entrance and begin to forage in the immediate vicinity.

不久，體型稍大的螞蟻孵化出來，它們的體型剛好可以離開巢穴入口，開始在附近覓食。

They collect bits of leaves and add them to the fungus culture.

他們收集樹葉碎屑，並將其加入真菌培養物中。

And on top of foraging, all of these worker ants so far are also the ideal size for tending to the brood.

除了覓食，這些工蟻的體型也非常適合照顧雛蟻。

At this point, the queen stops doing any fungal tending and just becomes an egg-laying machine.

這時，蜂后就不再做任何真菌護理工作，而是變成了一個產卵機器。

And now, the colony can take care of all of the essential tasks, egg-laying, brood tending, foraging, and fungal maintenance.

現在，蜂群可以承擔所有基本任務，包括產卵、育雛、覓食和真菌維護。

But this isn't enough to ensure the colony's survival, because predators are lurking nearby.

但這還不足以確保蟻群的生存，因為附近潛伏著掠食者。

Army ants are known to raid leafcutter ant nests and prey on leafcutter brood young.

眾所周知，陸軍螞蟻會襲擊切葉蟻的巢穴，並捕食切葉蟻的幼蟻。

And larger animals like birds, bats, and spiders are known to feed on atta queens.

據瞭解，鳥類、蝙蝠和蜘蛛等大型動物都以阿塔皇后為食。

Without adequate protection, leafcutter ant colonies would be pillaged.

如果沒有足夠的保護，切葉蟻群就會遭到掠奪。

So at this point in the colony's life cycle, a new cast of ant emerges.

是以，在蟻群生命週期的這個階段，新的蟻群出現了。

The soldier cast.

阿兵哥投彈。

These extremely large major ants don't have any formic acid.

這些體型極其龐大的主要螞蟻身上沒有任何甲酸。

They don't have a sting.

它們沒有刺。

But what they do have are extremely sharp mandibles powered by massive adductor muscles.

不過，它們的下顎非常鋒利，由巨大的內收肌提供動力。

Their heads can measure five millimeters wide and they can weigh around 50 milligrams.

它們的頭部寬 5 毫米，重約 50 毫克。

And they are especially good at defending against large enemies.

它們尤其擅長防禦大型敵人。

Large soldiers can even pierce human skin.

大型阿兵哥甚至可以刺穿人的皮膚。

And this bite force is around 2.5 times greater than scientists thought it should be.

而這種咬合力比科學家想象的要大大約 2.5 倍。

You might expect that a soldier ant that is 30 times as heavy as a smaller worker would have a bite force that is 30 times as strong.

你可能會想到，體重是小工蟻 30 倍的兵蟻的咬合力也會是小工蟻的 30 倍。

But it's actually around 80 times as strong.

但實際上，它的強度約為 80 倍。

Scientists analyzed the heads of these massive soldiers and found the reason to be an increased amount of muscle volume compared to the smaller ants.

科學家們分析了這些龐大阿兵哥的頭部，發現原因是與較小的螞蟻相比，它們的肌肉體積增大了。

And with these absolutely yoked bodyguards, along with some of the smaller workers also taking on defense tasks like against the parasitic flies, the leafcutter colony can grow their numbers and even expand their territory.

有了這些絕對的 "保鏢"，再加上一些體型較小的工蟻也承擔起防禦任務（如對付寄生蠅），剪葉蟲群就能增加數量，甚至擴大領地。

But with increasing numbers, the colony needs increasing food.

但隨著數量的增加，蟻群需要的食物也越來越多。

Therefore, the colony needs the fungal garden to grow larger.

是以，菌落需要真菌花園來壯大。

And for this, they need much more leaf mass.

為此，它們需要更多的葉片。

And the minims can no longer keep up with foraging duties.

而最小的動物已經無法完成覓食任務了。

Enter the mediae workers.

進入媒體工作者。

These medium-sized ants are built to foray far into the world to gather resources in the form of tons and tons of leaves.

這些中等體型的螞蟻可以遠涉重洋，收集成噸成噸的樹葉等資源。

Unlike the minima who can carry out a number of different tasks like brood and fungus tending and minor foraging, the mediae workers do little else except cut leaves and bring them home.

與可以執行多種不同任務（如照料雛鳥和真菌以及少量覓食）的迷你蜂不同，媒介蜂除了剪葉子並把它們帶回家外，幾乎不做其他事情。

This intermediate size is optimized for exactly this job.

這種中間尺寸正是為這項工作而優化的。

With all of these different sizes of ant, there's one obvious question.

面對這麼多不同大小的螞蟻，有一個顯而易見的問題。

How do the different worker casts appear in the right order?

不同的工人如何按正確的順序出現？

And how does the colony ensure it has the right number of each of them?

殖民地又是如何確保每種生物都有正確的數量呢？

It all comes back to the queen.

這一切都要歸功於女王。

The queen lays eggs with varying nutritional content, which contributes to size differences in the developing larvae.

蟻后產下的卵營養成分各不相同，導致發育中的幼蟲體型各異。

And the size of a developing ant larva determines which cast it will become.

發育中的螞蟻幼蟲的大小決定了它會變成哪種螞蟻。

This, along with the different baby daddies, gives rise to all the different phenotypes.

這樣，再加上不同的孩子爸爸，就產生了各種不同的表型。

How the queen knows when it's time to lay the right eggs and inhibit the growth of some versus others probably comes down to environmental cues.

蟻后如何知道什麼時候該產下合適的卵，並抑制某些卵的生長，而不是其他卵的生長，這可能要歸結於環境線索。

But with all of her workers now hatched into the world, the colony can truly blossom.

但是，隨著所有的工蟻都孵化到了這個世界上，蟻群才能真正開花結果。

During cutting, a worker usually anchors her hind legs on the leaf edge and slowly pivots around the body axis, pushing the cutting mandible through the leaf tissue.

在切割過程中，工蟻通常會將後腿固定在葉片邊緣，然後慢慢繞身體軸轉動，推動切割下顎穿過葉片組織。

This is why their cuttings are usually semi-circles.

這就是為什麼它們的插條通常是半圓形的。

As they cut, one side of the mandible inches across the leaf and the other drags as it cuts.

在切割時，下顎的一側在葉片上劃過，另一側則拖著葉片切割。

The head of a leaf cutter has strong muscles attached to its mandibles, and the mandible itself is made of chitin nanofibers and proteins and coated in a heavy element biomaterial, a mixture of proteins and zinc, making them as durable as a stainless steel knife.

切葉刀的頭部有強壯的肌肉與下顎相連，下顎本身由甲殼素納米纖維和蛋白質製成，並塗有重元素生物材料（蛋白質和鋅的混合物），使其像不鏽鋼刀一樣耐用。

And when you compare these media mandibles to the minima mandibles, you can see a clear difference in form, with the media mandibles much more robust and specialized for cutting.

當你將這些介質下顎與微型下顎進行比較時，你會發現兩者在形態上有明顯的不同，介質下顎更加堅固，專門用於切割。

This sharp and durable anatomy allows leaf cutter ants to cut thousands of leaf fragments in its lifetime.

這種鋒利耐用的解剖結構讓切葉蟻在一生中能切下成千上萬片樹葉碎片。

But there's one more thing that helps a leaf cutter ant cut leaves that is kind of unexpected.

不過，還有一樣東西能幫助切葉蟻切葉，這有點出乎意料。

And that is sound.

這就是聲音。

If you listen closely to leaf cutter ants cutting leaves, you hear some clicks.

如果你仔細聽切葉蟻切割樹葉的聲音，就會聽到一些咔嗒聲。

That is the sound of the mandibles cutting the leaf, and you'll hear a background sort of humming or chirping.

這是下顎切割樹葉的聲音，你會聽到一種背景的嗡嗡聲或鳴叫聲。

This is a high-frequency vibration called a stridulation, and it's produced by the stridulatory organ.

這是一種高頻振動，被稱為 "顫動"，由顫動器官產生。

This organ is located on the gaster and is made up of a file and scraper.

這個器官位於瓣鰓上，由銼刀和刮刀組成。

When the ant rubs the file against the scraper, an audible vibration is made.

當螞蟻將銼刀與刮刀摩擦時，就會發出聲音振動。

And this vibration stiffens the soft leaf, making it easier for the ant to cut it.

這種振動會使柔軟的葉子變硬，使螞蟻更容易切割它。

And these stridulations serve another incredible purpose.

而這些吟唱還有另一個不可思議的作用。

Ants can use them to communicate.

螞蟻可以用它們來交流。

If you've seen video clips like this, leaf cutter ants have the tendency to completely demolish certain leaves, while leaving other leaves almost completely untouched.

如果你看過這樣的視頻剪輯，切葉蟻往往會完全摧毀某些樹葉，而其他樹葉則幾乎完全不動。

The leaves that get demolished seem to be more desirable.

被拆掉的樹葉似乎更受歡迎。

Maybe they are more tender or have more sugar quantity.

也許它們更嫩，或者含糖量更高。

And in experiments, scientists found that significantly more ants stridulated when cutting tender leaves than tough leaves.

科學家在實驗中發現，切割嫩葉時發出的蟻叫聲明顯多於切割硬葉時。

And similarly, when the scientists coated the leaves in sugar, almost all of the workers stridulated.

同樣，當科學家們在樹葉上塗上糖時，幾乎所有的工人都會發出喘息聲。

The vibrations are affected by the quality of the leaves, and the stridulations act as a way to communicate to nearby ants to come and get some.

振動受樹葉品質的影響，蟻群通過敲擊聲來通知附近的螞蟻過來採食。

This is one of those moments where it's fun to wonder which came first.

在這種情況下，我們不禁要問，到底是哪個先出現的？

Did the stridulations evolve to facilitate leaf cutting and the communication about those leaves came as a result?

難道是為了方便剪葉而演化出了踔厲聲，並由此產生了關於這些葉子的交流？

This is what I would have guessed.

這就是我的猜測。

But scientists think it's actually the opposite, that facilitation in cutting leaves is more likely an auxiliary benefit emerging from the communication process.

但科學家們認為，這實際上恰恰相反，促進剪葉更可能是交流過程中產生的一種輔助益處。

Scientists think this partly because this stridulation is used in other contexts for communication as well.

科學家們認為，這部分是因為在其他情況下也會使用這種 "stridulation "來進行交流。

When an ant accidentally gets buried, for example, they stridulate to call for help.

例如，當螞蟻不小心被埋葬時，它們會發出求救聲。

And the vibrations are used to coordinate things like nest building and excavation.

振動用於協調築巢和挖掘等活動。

But these vibrations are only a small part of the communication of leaf cutter ants.

但這些振動只是切葉蟻交流的一小部分。

Their chemical communication is one of the most robust in the animal kingdom.

它們的化學通訊是動物界最強大的通訊方式之一。

And much of it occurs on harvesting roots.

其中大部分是在收穫根莖時發生的。

If you ever wander into leaf cutter ant territory, you might notice a parting of the leaves on the ground, like Aunt Moses himself had been there.

如果你曾誤入切葉蟻的領地，你可能會注意到地上的樹葉被分開了，就像摩西大媽親自到過那裡一樣。

But this was no Aunt Moses.

但這不是摩西姑媽。

It is a leaf cutter trail, cleared fastidiously by thousands of workers.

這是一條由數千名工人精心清理的樹葉切割小徑。

Of all of the animals in the world that construct trails, like elephants, cattle, or voles, Atta ants have the most complex trail construction behavior.

世界上所有像大象、牛或田鼠一樣建造足跡的動物中，阿塔蟻的足跡建造行為最為複雜。

Workers remove vast amounts of vegetation, cut passes through large obstacles, and level the soil to make a smooth surface.

工人們要清除大量植被，鑿穿大型障礙物，平整土地，使表面光滑。

On average, colonies clear nearly three kilometers of trail per year.

殖民地平均每年清理近三公里的小路。

And these routes lead masses of foragers to and from harvesting sites.

這些路線引領著大批覓食者往返於採摘地點。

And the way the ants begin these trails and continue to follow them is not through vision, but through scent.

螞蟻開始追蹤並繼續追蹤的方式不是通過視覺，而是通過氣味。

The ants chemically mark the trail with secretions from their poison gland sacs with two goals in mind.

螞蟻用毒腺囊的分泌物在蹤跡上做化學標記有兩個目的。

One, to recruit other ants to join the trail, and two, to create a long lasting orientation cue.

其一，招募其他螞蟻加入追蹤；其二，創建一個持久的定向線索。

To recruit other colony members, the ants release a particularly volatile chemical signal, which makes sense.

為了招募其他蟻群成員，螞蟻會釋放一種特別易揮發的化學信號，這也是合情合理的。

So the signal travels farther and can attract ants from farther distances.

是以，信號傳播得更遠，能吸引更遠距離的螞蟻。

And to leave a lasting chemical signal that delineates the trail, the ants release a chemical that is much less volatile, which also makes sense as volatile signals don't last very long.

為了留下持久的化學信號來劃定蹤跡，螞蟻會釋放一種揮發性小得多的化學物質，這也是有道理的，因為揮發性信號不會持續很長時間。

And the volatile compound in some Atta species is mind-blowingly effective.

而某些 Atta 種類中的揮發性化合物功效驚人。

Scientists found that workers of one Atta species follow trails with minuscule amounts of their volatile ant trail pheromone.