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  • A herd of wildebeests, a shoal of fish,

    一群牛羚, 一群魚, 和一群飛鳥

  • a flock of birds.

    很多動物都喜歡集結成群

  • Many animals gather in large groups

    這是自然界中最美妙的一件事

  • that are among the most wonderful spectacles

    但是為什麼要成群結隊呢?

  • in the natural world.

    最常見的說法是

  • But why do these groups form?

    為了安全或方便狩獵, 又或者交配與繁殖,

  • The common answers include things like

    以上的這些解釋,

  • seeking safety in numbers or hunting in packs

    通常都是正確的,

  • or gathering to mate or breed,

    這些都是人類對於 動物們在行為上的假設

  • and all of these explanations,

    這些動物們可以控制牠們的行為

  • while often true,

    並對自己的身體負責

  • make a huge assumption about animal behavior,

    但是通常卻不是這麼一回事

  • that the animals are in control of their own actions,

    這是豐年蝦 (鹵蟲), 一種鹽水蝦

  • that they are in charge of their bodies.

    又常被稱之為 ”海猴子“

  • And that is often not the case.

    牠非常的小, 通常習慣獨居

  • This is Artemia, a brine shrimp.

    但是牠也可以集結成 像這一大片的紅色群體

  • You probably know it better as a sea monkey.

    大到足以用公尺(米)為單位來計算

  • It's small, and it typically lives alone,

    這些豐年蝦之所以聚集,是因為寄生蟲

  • but it can gather in these large red swarms

    這些蝦子都被 “絛蟲” 給感染了

  • that span for meters,

    絛蟲 (寄生蟲) 實際上就像是 一條既長又活生生的腸子

  • and these form because of a parasite.

    一端是生殖器, 另一端是帶鉤的口腔

  • These shrimp are infected with a tapeworm.

    身為一個自由的撰稿人, 我很同情牠

  • A tapeworm is effectively a long, living gut

    (群眾笑聲)

  • with genitals at one end and a hooked mouth at the other.

    絛蟲吸附在豐年蝦的身上 並吸取牠的養分,

  • As a freelance journalist, I sympathize.

    不止這樣, 絛蟲還做了另外一件事

  • (Laughter)

    絛蟲閹割了這些豐年蝦

  • The tapeworm drains nutrients from Artemia's body,

    絛蟲把這些豐年蝦從本身的 透明色轉變成了亮紅色,

  • but it also does other things.

    絛蟲讓這些豐年蝦活得更久,

  • It castrates them,

    生物學家尼可拉斯.羅得發現

  • it changes their color from transparent to bright red,

    寄生的絛蟲讓這些 原本獨居的蝦集結在一起

  • it makes them live longer,

    為什麼呢? 因為這些絛蟲 就像是其他的寄生物種一樣,

  • and as biologist Nicolas Rode has found,

    有著複雜的生活形態

  • it makes them swim in groups.

    擁有很多不同的宿主

  • Why? Because the tapeworm, like many other parasites,

    寄生在這些蝦身上只是 這些絛蟲旅程的第一步

  • has a complicated life cycle

    牠們的最終目的是這個,

  • involving many different hosts.

    大紅鶴

  • The shrimp are just one step on its journey.

    只有在紅鶴身上, 這些絛蟲才得以繁衍

  • Its ultimate destination is this,

    所以為了要達到目的, 絛蟲只能先行操縱蝦子宿主

  • the greater flamingo.

    進而形成這些顯眼的紅色蝦群

  • Only in a flamingo can the tapeworm reproduce,

    這樣才能更輕易地吸引紅鶴的注意

  • so to get there, it manipulates its shrimp hosts

    並獵捕吞食,

  • into forming these conspicuous colored swarms

    而這就是豐年蝦群集的秘密.

  • that are easier for a flamingo to spot

    豐年蝦並不是依 自身意志組成的群居動物

  • and to devour,

    而是因為豐年蝦被控制了

  • and that is the secret of the Artemia swarm.

    群體生活看似無法提供安全感

  • They aren't sociable through their own volition,

    實際上卻剛好相反

  • but because they are being controlled.

    絛蟲入侵了這些 豐年蝦的大腦與身體,

  • It's not safety in numbers.

    並把這些豐年蝦當作

  • It's actually the exact opposite.

    進入紅鶴體內的一項交通工具

  • The tapeworm hijacks their brains and their bodies,

    這裡還有另外一個

  • turning them into vehicles

    寄生蟲操縱宿主的案例

  • for getting itself into a flamingo.

    這是一隻具自殺傾向的蟋蟀

  • And here is another example

    這隻蟋蟀吞食了鐵線蟲的幼蟲,

  • of a parasitic manipulation.

    鐵線蟲又名馬鬃蟲

  • This is a suicidal cricket.

    蟲子會在蟋蟀身體裡長到成蟲,

  • This cricket swallowed the larvae of a Gordian worm,

    但是牠(鐵線蟲)必須在水裡交配,

  • or horsehair worm.

    當鐵線蟲需要交配時 就會分泌特殊蛋白質

  • The worm grew to adult size within it,

    腐蝕蟋蟀的大腦,

  • but it needs to get into water in order to mate,

    造成蟋蟀行為失常.

  • and it does that by releasing proteins

    當蟋蟀靠近水邊的時候,

  • that addle the cricket's brain,

    例如這個游泳池邊,

  • causing it to behave erratically.

    牠就會跳入水裡並淹死自己,

  • When the cricket nears a body of water,

    這時鐵線蟲就會

  • such as this swimming pool,

    從死屍裡蠕動而出.

  • it jumps in and drowns,

    蟋蟀體內很寬敞. 但是誰知道呢?

  • and the worm wriggles out

    絛蟲和鐵線蟲並不孤單

  • of its suicidal corpse.

    牠們是控制大腦的

  • Crickets are really roomy. Who knew?

    寄生蟲軍團的一份子

  • The tapeworm and the Gordian worm are not alone.

    像是真菌, 病毒, 蠕蟲, 昆蟲等等

  • They are part of an entire cavalcade

    這些都是擅長攪亂及重寫

  • of mind-controlling parasites,

    宿主們本身意願的寄生體

  • of fungi, viruses, and worms and insects and more

    當我約20年前第一次

  • that all specialize in subverting and overriding

    從大衛·阿滕伯勒的書 《生命的征途》上

  • the wills of their hosts.

    學習到這種生物形態

  • Now, I first learned about this way of life

    再從另一本非常好的書

  • through David Attenborough's "Trials of Life"

    由我朋友卡爾·齊默 撰寫的《霸王寄生蟲》上見到

  • about 20 years ago,

    之後我就以這些生物 為主題不停地寫作至今

  • and then later through a wonderful book called

    還有一些生物學的主題令我更加著迷

  • "Parasite Rex" by my friend Carl Zimmer.

    這感覺就像是這些 寄生蟲已經竄改了我的大腦

  • And I've been writing about these creatures ever since.

    因為畢竟, 牠們是如此地引人注目

  • Few topics in biology enthrall me more.

    卻又同時令人感到毛骨悚然

  • It's like the parasites have subverted my own brain.

    當你在寫關於寄生蟲的文章時,

  • Because after all, they are always compelling

    你的詞彙量張嘴就是 "活活吞噬"

  • and they are delightfully macabre.

    閉口就是 “衝出身體”。

  • When you write about parasites,

    (群眾笑聲)

  • your lexicon swells with phrases like

    不僅如此

  • "devoured alive" and "bursts out of its body."

    我是個作家, 觀眾席裡有些人也是作家

  • (Laughter)

    作家都知道每個人都喜歡故事

  • But there's more to it than that.

    寄生蟲讓我們拒絕撰寫那些

  • I'm a writer, and fellow writers in the audience

    淺顯易見的故事情節的誘惑

  • will know that we love stories.

    牠們生存的世界是劇情的轉折點之一

  • Parasites invite us to resist the allure

    也是無法預測的解釋

  • of obvious stories.

    為什麼? 例如,

  • Their world is one of plot twists

    這隻毛毛蟲

  • and unexpected explanations.

    當其他昆蟲靠近牠

  • Why, for example,

    和那些白色蟲繭的時候

  • does this caterpillar

    毛毛蟲是在開始激烈反抗嗎?

  • start violently thrashing about

    毛毛蟲貌似在站崗護衛這些繭

  • when another insect gets close to it

    難道毛毛蟲在保護牠的兄弟姐妹嗎?

  • and those white cocoons that it seems

    不是的

  • to be standing guard over?

    這隻毛毛蟲是被寄生蜂給攻擊

  • Is it maybe protecting its siblings?

    並被體內產卵

  • No.

    寄生蜂的蛋將孵化在 毛毛蟲的體內,

  • This caterpillar was attacked

    而這隻寄生蜂幼蟲 在衝破毛毛蟲的身體之前

  • by a parasitic wasp which laid eggs inside it.

    將毛毛蟲從內部活活吞食

  • The eggs hatched and the young wasps

    你們了解我的意思了嗎?

  • devoured the caterpillar alive

    然而, 這隻毛毛蟲還在苟延殘喘

  • before bursting out of its body.

    有些寄生蜂卻背後

  • See what I mean?

    控制著這只毛毛蟲

  • Now, the caterpillar didn't die.

    保護自己的兄弟姐妹

  • Some of the wasps seemed to stay behind

    直到牠們在繭內破繭成蟲

  • and controlled it into defending their siblings

    這隻毛毛蟲只是一隻 搖頭晃腦的殭屍保鏢

  • which are metamorphosing

    保護著那些殺死自己的

  • into adults within those cocoons.

    生物的後代(寄生蜂的後代)

  • This caterpillar is a head-banging zombie bodyguard

    (群眾掌聲)

  • defending the offspring

    我們還有很多要說, 而我只有13分鐘 (群眾笑聲)

  • of the creature that killed it.

    現在, 你們有些人可能

  • (Applause)

    只是拼命地尋求一些慰藉

  • We have a lot to get through. I only have 13 minutes. (Laughter)

    說這些都只是自然界裡的怪事,

  • Now, some of you are probably just

    這些發生的事情都是離群值,

  • desperately clawing for some solace

    這些論點都是可被理解的,

  • in the idea that these things are oddities

    因為牠們的天性, 寄生體是很小的

  • of the natural world, that they are outliers,

    牠們花費很多的時間

  • and that point of view is understandable,

    在別的物種身上

  • because by their nature, parasites are quite small

    牠們很容易被小看,

  • and they spend a lot of their time

    但是這不代表牠們不重要

  • inside the bodies of other things.

    幾年前, 有個名叫凱文·拉弗蒂的人

  • They're easy to overlook,

    帶了一群科學家去了加州的三個河口

  • but that doesn't mean that they aren't important.

    他們幾乎將能找到的所有東西

  • A few years back, a man called Kevin Lafferty

    通通稱重, 解剖, 及記錄了下來,

  • took a group of scientists into three Californian estuaries

    他們發現

  • and they pretty much weighed and dissected

    寄生物種非常豐富多元

  • and recorded everything they could find,

    尤其是吸蟲類最為常見,

  • and what they found

    牠們(吸蟲)是專門閹割宿主的微小蠕蟲

  • were parasites in extreme abundance.

    好比這隻不幸的蝸牛

  • Especially common were trematodes,

    現在, 單一隻吸蟲是十分微小的, 僅能依靠顯微鏡觀測

  • tiny worms that specialize in castrating their hosts

    但是全體加起來的重量就和

  • like this unfortunate snail.

    河口裡所有的魚一樣重

  • Now, a single trematode is tiny, microscopic,

    或者是所有鳥類總重的三到九倍之多

  • but collectively they weighed as much

    還記得我剛才給你們看的鐵線蟲

  • as all the fish in the estuaries

    和那隻蟋蟀嗎?

  • and three to nine times more than all the birds.

    有個名叫佐藤拓也的日本科學家

  • And remember the Gordian worm that I showed you,

    在一段河流裡發現

  • the cricket thing?

    這些寄生蟲控制著很多的蟋蟀

  • One Japanese scientist called Takuya Sato

    和蚱蜢跳入水中

  • found that in one stream,

    進而淹死這些昆蟲

  • these things drive so many crickets

    而這些昆蟲占了當地鱒魚60%的食物來源

  • and grasshoppers into the water

    這些操控並不是奇怪的事

  • that the drowned insects

    這是發生在我們週遭, 很複雜

  • make up some 60 percent of the diet of local trout.

    卻又平常的世界的一部份

  • Manipulation is not an oddity.

    科學家目前發現了

  • It is a critical and common part

    數百種這類型的案例,

  • of the world around us,

    更令人振奮的是, 科學家們開始了解

  • and scientists have now found

    這些寄生體到底是 怎麼控制牠們宿主的

  • hundreds of examples of such manipulators,

    這是我最喜歡的案例之一

  • and more excitingly, they're starting to understand

    這是安瓿牛鞭

  • exactly how these creatures control their hosts.

    也叫扁頭泥蜂

  • And this is one of my favorite examples.

    還有件眾所皆知的事

  • This is Ampulex compressa,

    就是這些扁頭泥蜂

  • the emerald cockroach wasp,

    會自己的卵

  • and it is a truth universally acknowledged

    產在蟑螂的身上

  • that an emerald cockroach wasp in possession

    當牠(扁頭泥蜂)找到一隻(蟑螂)時

  • of some fertilized eggs

    牠(扁頭泥蜂)用牠的刺來叮螫蟑螂

  • must be in want of a cockroach.

    而刺同時也是牠的感覺器官

  • When she finds one,

    這些都是三個禮拜前的新發現

  • she stabs it with a stinger

    牠(扁頭泥蜂)的刺, 也就是牠的感覺器官

  • that is also a sense organ.

    有著細小的感官突起物

  • This discovery came out three weeks ago.

    這些突起物可以讓牠感受到

  • She stabs it with a stinger that is a sense organ

    蟑螂大腦組織的特殊質地

  • equipped with small sensory bumps

    就像是一個人盲目的 在一個袋子裡尋找,

  • that allow her to feel the distinctive texture

    當扁頭泥蜂找到大腦時, 會將毒液注進