I study ants, and that's because I like to think about how organizations work. And in particular, how the simple parts of organizations interact to create the behavior of the whole organization. So, ant colonies are a good example of an organization like that, and there are many others. The web is one. There are many biological systems like that -- brains, cells, developing embryos.
我研究螞蟻,因為我喜歡思考組織的運作方式, 尤其想知道,單一的個體是如何透過互動的方式, 就能創造出複雜完整的組織行為。 而蟻群就是最好的例子, 其它像是網路, 很多的生物系統,像是 大腦、細胞、發育中的胚胎都是類似的例子。
There are about 10,000 species of ants. They all live in colonies consisting of one or a few queens, and then all the ants you see walking around are sterile female workers. And all ant colonies have in common that there's no central control. Nobody tells anybody what to do. The queen just lays the eggs. There's no management. No ant directs the behavior of any other ant. And I try to figure out how that works. And I've been working for the past 20 years on a population of seed-eating ants in southeastern Arizona.
螞蟻大約有一萬多種品種, 他們的蟻群都會有一隻或幾隻蟻后, 而那些走來走去的螞蟻,都是沒有生育能力的雌性工蟻, 而且所有蟻群都有一個共同點,就是他們沒有中央領導。 沒有任何一隻工蟻被告知該做什麼事, 蟻后只顧生蛋,她並不做任何管理的事情, 沒有任何一隻螞蟻指揮其它螞蟻該做什麼事, 我想試著了解他們是怎麼運作的, 所以我過去二十年, 一直在亞利桑那州的東南部,研究一種會吃種子的螞蟻,
Here's my study site. This is really a picture of ants, and the rabbit just happens to be there. And these ants are called harvester ants because they eat seeds. This is the nest of the mature colony, and there's the nest entrance. And they forage maybe for about 20 meters away, gather up the seeds and bring them back to the nest, and store them. And every year I go there and make a map of my study site. This is just a road. And it's not very big: it's about 250 meters on one side, 400 on the other. And every colony has a name, which is a number, which is painted on a rock. And I go there every year and look for all the colonies that were alive the year before, and figure out which ones have died, and put all the new ones on the map. And by doing this I know how old they all are. And because of that, I've been able to study how their behavior changes as the colony gets older and larger.
這就是我研究的地方。這真的是一張螞蟻的照片, 只是剛好有隻兔子在那。 這些螞蟻被稱作收割蟻,因為他們吃種子。 這是一個發展健全的蟻巢,而且那裡有一個入口, 裡面的螞蟻們可能會到20公尺遠的地方覓食, 蒐集種子並且把它們帶回巢穴儲存。 每一年我都會去那裡,製作一張蟻群分佈的地圖, 只是一條路的範圍,不是很大, 大約有250公尺長,400公尺寬。 這裡的每個蟻群都有各自的編號, 編號被標記在石頭上,所以每年我都可以回去那裡, 找出所有蟻群過去一年居住的位置, 然後觀察哪些蟻群已經滅絕,並在地圖上標註出新蟻群。 持續透過這樣的工作,我可以知道這些蟻群活了多久, 也因為如此,隨著蟻群的成長及擴張, 我可以研究他們的行為變化。
So I want to tell you about the life cycle of a colony. Ants never make more ants; colonies make more colonies. And they do that by each year sending out the reproductives -- those are the ones with wings -- on a mating flight. So every year, on the same day -- and it's a mystery exactly how that happens -- each colony sends out its virgin, unmated queens with wings, and the males, and they all fly to a common place. And they mate. And this shows a recently virgin queen. Here's her wings. And she's in the process of mating with this male, and there's another male on top waiting his turn. Often the queens mate more than once. And after that, the males all die. That's it for them.
我想先來談談關於蟻群的生命週期。 絕大部分的螞蟻不能繁殖,但蟻群卻可以生產更多蟻群, 這是因為他們每年都會派出那些有翅膀的生殖蟻, 飛到蟻穴之外交配。 而且很神奇的,都剛好在每年的同一天, 每個蟻群都會在那天送出長有翅膀的新蟻后與公蟻, 一起飛到同個地方交配。 這是一隻最近拍攝到的新蟻后,那是她的翅膀, 她正在跟這隻公蟻交配, 而且還有另一隻公蟻在上面等,等待輪到他交配。 通常每隻新蟻后都會交配一次以上, 交配完,公蟻就會死,那就是他們的用處。
(Laughter)
(笑聲)
And then the newly mated queens fly off somewhere, drop their wings, dig a hole and go into that hole and start laying eggs. And they will live for 15 or 20 years, continuing to lay eggs using the sperm from that original mating. So the queen goes down in there. She lays eggs, she feeds the larvae -- so an ant starts as an egg, then it's a larva. She feeds the larvae by regurgitating from her fat reserves. Then, as soon as the ants -- the first group of ants -- emerge, they're larvae. Then they're pupae. Then they come out as adult ants. They go out, they get the food, they dig the nest, and the queen never comes out again.
接著這些懷孕的新蟻后會飛到某個地方,褪去她們的翅膀, 挖一個洞,鑽進去,然後開始產卵。 她們會活15到20年,並且利用與公蟻交配時留下的精液, 每年持續不斷地產卵。 女王由此誕生。 螞蟻是卵生的,女王會持續地產卵並扶養幼蟲, 她利用反芻的方式,將體內豐富的貯存物餵食給幼蟲, 然後,她的第一批子民開始湧現, 他們很快地從幼蟲變成蛹,然後破繭而出變為成蟻。 這些成蟻會出去找食物,或蓋巢穴, 而女王從此不再踏出她的王宮。
So this is a one-year-old colony -- this happens to be 536. There's the nest entrance, there's a pencil for scale. So this is the colony founded by a queen the previous summer. This is a three-year-old colony. There's the nest entrance, there's a pencil for scale. They make a midden, a pile of refuse -- mostly the husks of the seeds that they eat. This is a five-year-old colony. This is the nest entrance, here's a pencil for scale. This is about as big as they get, about a meter across. And then this is how colony size and numbers of worker ants changes -- so this is about 10,000 worker ants -- changes as a function of colony age, in years. So it starts out with zero ants, just the founding queen, and it grows to a size of about 10 or 12 thousand ants when the colony is five. And it stays that size until the queen dies and there's nobody to make more ants, when she's about 15 or 20 years old. And it's when they reach this stable size, in numbers of ants, that they start to reproduce. That is, to send more winged queens and males to that year's mating flight. And I know how colony size changes as a function of colony age because I've dug up colonies of known age and counted all the ants. (Laughter) So that's not the most fun part of this research, although it's interesting.
這是一個一歲大的蟻群,它的編號是536, 那裡有一個巢穴的入口,鉛筆是比例尺, 這是由某隻蟻后在去年夏天所建立的。 這是一個三歲大的蟻群, 巢穴的入口在那裡,鉛筆是比例尺, 他們在那裡丟了一堆廢棄物,大部分是吃剩的穀殼。 這是一個五歲大的蟻群,那是巢穴入口,鉛筆是比例尺, 這蟻群已成長至最大,大約一公尺長。 這張圖是用來觀察蟻群大小和工蟻數的變化, 所以這(五歲大的)蟻群大約有一萬隻工蟻, 蟻群大小的變化是蟻群年紀的函數,單位是年。 所以蟻群在蟻后建立之初,並沒有任何其它的螞蟻, 但在五年後,它會成為一萬到一萬兩千隻螞蟻的蟻群, 並且在蟻后死去之前,一直維持這樣的數量規模, 蟻后約在15到20歲時便停止生產。 而當蟻群的數量達到穩定的大小時, 它就會開始複製新的蟻群, 也就是一年一度送出有翅的新蟻后與公蟻,讓他們飛到外面交配。 而我之所以敢說蟻群的大小會隨著蟻群年紀變化, 是因為我挖開過每一個已知歲數的蟻群,還數過所有螞蟻的數量, 這還不算是這研究最好玩的部分,不過是蠻很有趣的啦。
(Laughter)
(笑聲)
Really the question that I think about with these ants is what I call task allocation. That's not just how is the colony organized, but how does it change what it's doing? How is it that the colony manages to adjust the numbers of workers performing each task as conditions change? So, things happen to an ant colony. When it rains in the summer, it floods in the desert. There's a lot of damage to the nest, and extra ants are needed to clean up that mess. When extra food becomes available -- and this is what everybody knows about picnics -- then extra ants are allocated to collect the food. So, with nobody telling anybody what to do, how is it that the colony manages to adjust the numbers of workers performing each task? And that's the process that I call task allocation.
其實我真正想從這些螞蟻身上了解的是"任務分配"的問題, 這不僅僅是蟻群如何組織的問題, 而是蟻群如何改變自己的行為? 當狀況有變時,他們如何 調派足夠的工蟻去執行各項工作? 蟻群可能會碰到下面這些狀況: 夏天的雨水會淹沒這片沙漠, 而重創蟻巢, 那麼就需要多派些螞蟻來災後重建; 而當有螞蟻發現新的食物, 每隻螞蟻都會知道野餐時間到了, 那麼就要多分派些螞蟻去搬回這些食物。 所以,在沒有任何人指揮的情況下, 蟻群是如何做到派遣足夠的工蟻去執行各項任務的呢? 而這就是我所謂的"任務分配"問題。
And in harvester ants, I divide the tasks of the ants I see just outside the nest into these four categories: where an ant is foraging, when it's out along the foraging trail, searching for food or bringing food back. The patrollers -- that's supposed to be a magnifying glass -- are an interesting group that go out early in the morning before the foragers are active. They somehow choose the direction that the foragers will go, and by coming back -- just by making it back -- they tell the foragers that it's safe to go out. Then the nest maintenance workers work inside the nest, and I wanted to say that the nests look a lot like Bill Lishman's house. That is, that there are chambers inside, they line the walls of the chambers with moist soil and it dries to a kind of an adobe-like surface in it. It also looks very similar to some of the cave dwellings of the Hopi people that are in that area. And the nest maintenance workers do that inside the nest, and then they come out of the nest carrying bits of dry soil in their mandibles. So you see the nest maintenance workers come out with a bit of sand, put it down, turn around, and go back in. And finally, the midden workers put some kind of territorial chemical in the garbage. So what you see the midden workers doing is making a pile of refuse. On one day, it'll all be here, and then the next day they'll move it over there, and then they'll move it back. So that's what the midden workers do. And these four groups are just the ants outside the nest. So that's only about 25 percent of the colony, and they're the oldest ants.
我將這種收割蟻所做的可能任務, 依照我在巢穴外觀查到的, 分成四大類,首先是覓食分隊, 他們的任務就是沿著覓食路徑出去找食物,並從原路帶食物回來。 再來是巡邏分隊--他們應該需要放大鏡-- 他們是很有趣的分隊,每天一大早 在覓食分隊行動前,他們就出門了。 不知他們是怎麼選擇方向的, 不過他們來回的路徑,就是之後覓食分隊的覓食路徑, 他們會告訴覓食分隊這些路是安全的。 再來是在蟻巢內工作的修護分隊, 我想說的是通常蟻巢看起就跟比爾.里斯曼的房子差不多, 也就是說裡面都是房間, 他們用潮濕的土壤來造隔間的牆, 牆乾了就會形成像泥磚般的表面。 蟻巢看起來也很像某些 當地印地安人的洞穴居。 此外修護工人們在造牆時, 他們也會用大顎搬一些乾掉的的泥土到巢穴外, 所以你可以看到修護工人夾著一些沙出來, 放在地上,轉個身,然後又回去洞穴。 最後是堆肥分隊,他們會把當地取得的某種化學物質放在垃圾中, 你會看到堆肥分隊不斷地在堆放廢棄物。 可能今天他們把廢棄物堆在這裡, 隔天把它移到另一個地方,然後哪一天又把它們移回來, 這就是堆肥分隊的工作。 這四個分隊都是需要走出巢穴工作的螞蟻, 他們只佔了整個蟻群的四分之一,但他們是年紀最大的螞蟻。
So, an ant starts out somewhere near the queen. And when we dig up nests we find they're about as deep as the colony is wide, so about a meter deep for the big old nests. And then there's another long tunnel and a chamber, where we often find the queen, after eight hours of hacking away at the rock with pickaxes. I don't think that chamber has evolved because of me and my backhoe and my crew of students with pickaxes, but instead because when there's flooding, occasionally the colony has to go down deep. So there's this whole network of chambers. The queen's in there somewhere; she just lays eggs. There's the larvae, and they consume most of the food. And this is true of most ants -- that the ants you see walking around don't do much eating. They bring it back and feed it to the larvae. When the foragers come in with food, they just drop it into the upper chamber, and other ants come up from below, get the food, bring it back, husk the seeds, and pile them up. There are nest maintenance workers working throughout the nest. And curiously, and interestingly, it looks as though at any time about half the ants in the colony are just doing nothing. So, despite what it says in the Bible, about, you know, "Look to the ant, thou sluggard," in fact, you could think of those ants as reserves. That is to say, if something happened -- and I've never seen anything like this happen, but I've only been looking for 20 years -- if something happened, they might all come out if they were needed. But in fact, mostly they're just hanging around in there.
每隻螞蟻都是從蟻后的身邊成長離開, 在我們挖了一些蟻巢後,才發現它們的深度 跟它們的寬度差不多,也就是說一個大的老巢大約有一公尺深, 裡面有個很長的地道,底部有個房間,我們常常可以在那裡找到蟻后, 這大約需要用鶴嘴鋤在土石裡挖八個小時。 我不認為那個房間會因為我的挖土機或我學生的鶴嘴鋤, 就會有所遷移; 但是當水災發生時, 蟻穴偶爾會繼續往更深處挖。 這是整個蟻穴的地下網絡, 蟻后就在那裡某處生蛋; 那邊是幼蟲,大部分的食物都是用來餵養他們。 可以說大部分你平常看到 在那走來走去的螞蟻,其實是吃很少的, 他們主要是把食物帶回去供養那些幼蟲。 當覓食分隊帶著食物回來時,他們通常只是把它放到較上層的存放室, 然後下層的螞蟻就會上來搬這些食物, 把它搬回去後,剝去種子的外殼,並堆放好。 那邊都是蟻巢的維護分隊,他們遍布整個蟻巢。 令人好奇且有趣的是,蟻群似乎總是有 大約一半的螞蟻是不做任何事的, 所以儘管聖經提到說: "懶鬼啊,看看螞蟻是多麼的勤勞", 事實上,你也許會想說他們可能是後備部隊, 也就是說,如果發生了某事--不過我倒是從沒看過這"某事"發生過, 儘管我只觀察它們二十年 -- 如果發生了某事,或許他們會傾巢而出也不一定。 但事實上,大部分的時候他們仍是逗留在蟻巢裡,
And I think it's a very interesting question -- what is there about the way the colony is organized that might give some function to a reserve of ants who are doing nothing? And they sort of stand as a buffer in between the ants working deep inside the nest and the ants working outside. And if you mark ants that are working outside, and dig up a colony, you never see them deep down. So what's happening is that the ants work inside the nest when they're younger. They somehow get into this reserve. And then eventually they get recruited to join this exterior workforce. And once they belong to the ants that work outside, they never go back down. Now ants -- most ants, including these, don't see very well. They have eyes, they can distinguish between light and dark, but they mostly work by smell. So just to reinforce that what you might have thought about ant queens isn't true -- you know, even if the queen did have the intelligence to send chemical messages through this whole network of chambers to tell the ants outside what to do, there is no way that such messages could make it in time to see the shifts in the allocation of workers that we actually see outside the nest. So that's one way that we know the queen isn't directing the behavior of the colony.
我覺得這是一個非常有趣的問題 -- 蟻群為什麼會是那樣的組織方式? 那些做為後備部隊不做任何事的螞蟻,他們扮演了什麼角色? 他們有點像介於在巢穴深處的工蟻 與在巢外的工蟻之間的緩衝角色, 如果你把那些在巢外的工蟻做上記號,然後挖開蟻巢, 在蟻巢深處,你是找不到一隻螞蟻是有記號的。 所以其實只有年輕的螞蟻會在蟻巢內工作, 他們以某種方式進入後備部隊, 最後他們會被徵募並加入外面的工蟻; 一旦他們被歸屬為外部的工蟻,他們就再也不會回到蟻巢的下層。 大部分的螞蟻,包括這些,他們的視力不怎麼好, 雖然他們有眼睛能夠區分明暗, 但是大部分他們依靠的是嗅覺。 所以我想再強調,你們過去對蟻后的印象 很可能是不正確, 即使蟻后是真的有智慧, 能夠經由巢穴中的內部網路,傳送化學訊息 去告訴所有外部的工蟻該做什麼, 但這些訊息也無法使那些工蟻像我們實際在巢外看到的那樣, 能夠迅速完成工作分派的調動與更替, 所以這是我們知道蟻后無法指揮整個蟻群的原因。
So when I first set out to work on task allocation, my first question was, "What's the relationship between the ants doing different tasks? Does it matter to the foragers what the nest maintenance workers are doing? Does it matter to the midden workers what the patrollers are doing?" And I was working in the context of a view of ant colonies in which each ant was somehow dedicated to its task from birth and sort of performed independently of the others, knowing its place on the assembly line. And instead I wanted to ask, "How are the different task groups interdependent?"
所以當我開始研究它們的"任務分配"時, 我第一個問題是"不同任務的分隊之間, 是否存在著某種關係?" 修護分隊做的工作對覓食分隊有重要的意義嗎? 巡邏分隊做的工作對堆肥分隊有重要的影響嗎? 而就我過去所知的觀點,每隻螞蟻 似乎從出生就一直致力於它的任務, 他們似乎明確知道他們的工作崗位在哪, 並且能夠獨立執行。 不過我想問的是,"不同任務的分隊之間是如何相互依賴的?"
So I did experiments where I changed one thing. So for example, I created more work for the nest maintenance workers by putting out a pile of toothpicks near the nest entrance, early in the morning when the nest maintenance workers are first active. This is what it looks like about 20 minutes later. Here it is about 40 minutes later. And the nest maintenance workers just take all the toothpicks to the outer edge of the nest mound and leave them there. And what I wanted to know was, "OK, here's a situation where extra nest maintenance workers were recruited -- is this going to have any effect on the workers performing other tasks?" Then we repeated all those experiments with the ants marked. So here's some blue nest maintenance workers. And lately we've gotten more sophisticated and we have this three-color system. And we can mark them individually so we know which ant is which. We started out with model airplane paint and then we found these wonderful little Japanese markers, and they work really well. And so just to summarize the result, well it turns out that yes, the different tasks are interdependent. So, if I change the numbers performing one task, it changes the numbers performing another. So for example, if I make a mess that the nest maintenance workers have to clean up, then I see fewer ants out foraging. And this was true for all the pair-wise combinations of tasks.
所以我做了一些小實驗, 比如說我在一大早,第一批維護分隊尚未行動時, 就放了一堆牙籤在蟻穴的入口附近, 以便增加維護分隊的工作份量。 這是二十分鐘後的狀況, 而這是四十分鐘後的狀況, 最後維護分隊把所有的牙籤 都堆放到巢穴的邊界去了。 而我想知道的是, 在這種情形下,維護分隊要招募更多的工蟻來支援, 而這會影響到其它分隊的工蟻嗎? 然後我們重覆這個實驗,並且將工蟻們作上記號, 我們把維護分隊標記為藍色。 接著我們再搞得複雜一些, 用三種顏色將工蟻 一隻隻的做標記,如此我們可以知道哪隻是哪隻。 我們一開始是用模型飛機的油漆, 但後來我們發現日本的小麥克筆, 非常適合用來做標記。 我簡述一下我們的實驗結果, 呃..沒錯,結果就是不同分隊的工蟻是彼此合作的, 也就是說如果我改變了一個分隊的工作份量, 那麼另一個分隊的工蟻數量就會跟著改變。 例如,我製造一些麻煩 讓維護分隊去整理它, 那麼我就會看到覓食分隊的工蟻減少了, 而所有的分隊都是這樣成對的消長組合。
And the second result, which was surprising to a lot of people, was that ants actually switch tasks. The same ant doesn't do the same task over and over its whole life. So for example, if I put out extra food, everybody else -- the midden workers stop doing midden work and go get the food, they become foragers. The nest maintenance workers become foragers. The patrollers become foragers. But not every transition is possible. And this shows how it works. Like I just said, if there is more food to collect, the patrollers, the midden workers, the nest maintenance workers will all change to forage. If there's more patrolling to do -- so I created a disturbance, so extra patrollers were needed -- the nest maintenance workers will switch to patrol. But if more nest maintenance work is needed -- for example, if I put out a bunch of toothpicks -- then nobody will ever switch back to nest maintenance, they have to get nest maintenance workers from inside the nest. So foraging acts as a sink, and the ants inside the nest act as a source. And finally, it looks like each ant is deciding moment to moment whether to be active or not.
第二個實驗結果可能會使很多人感到驚訝, 那就是工蟻其實是會調換工作的, 在工蟻的一生中,並不只是一直重覆做同樣的工作。 舉例來說,如果我多放一些食物, 其它堆肥分隊的工蟻就會停止堆肥,而轉去搬食物, 他們加入了覓食分隊! 維護分隊的工蟻也會加入覓食分隊, 巡邏分隊亦不例外。 不過並不是所有分隊之間都可以彼此轉換的,這是他們的運作方式, 就像我剛說的,如果有更多的食物要搜集, 無論是哪個分隊都會全力支援覓食分隊。 如果我製造了一些擾亂, 增加了巡邏分隊的工作量,那麼就需要更多的工蟻支援, 這時維護分隊的工蟻就會加入巡邏分隊。 但同時若也有工作需要維護分隊來完成, 舉例來說,我又放了一大堆牙籤, 這時就沒有其他分隊會調動回來做這些工作, 這時他們就不得不出動巢穴內的工蟻。 所以覓食任務是勞力的集中站,蟻穴內的工蟻便是勞力來源。 最後,看起來每隻螞蟻似乎 時時刻刻都在決定是否需要採取行動。
So, for example, when there's extra nest maintenance work to do, it's not that the foragers switch over. I know that they don't do that. But the foragers somehow decide not to come out. And here was the most intriguing result: the task allocation. This process changes with colony age, and it changes like this. When I do these experiments with older colonies -- so ones that are five years or older -- they're much more consistent from one time to another and much more homeostatic. The worse things get, the more I hassle them, the more they act like undisturbed colonies. Whereas the young, small colonies -- the two-year-old colonies of just 2,000 ants -- are much more variable. And the amazing thing about this is that an ant lives only a year. It could be this year, or this year. So, the ants in the older colony that seem to be more stable are not any older than the ants in the younger colony. It's not due to the experience of older, wiser ants. Instead, something about the organization must be changing as the colony gets older. And the obvious thing that's changing is its size.
所以,假如當維護分隊有額外工作需要支援時, 覓食分隊是不會前來支援的,我知道他們不會這麼做, 但是他們以某種方式決定不前來支援。 而這正是最吸引人的部分:任務分配。 這個過程會隨著蟻群的年齡而改變,這是它們改變的方式。 當我對較成熟的蟻群做這些實驗時, 就是那些五歲以上的蟻群, 他們顯然能一直保持著一致的調動模式, 而且協調得很好。即使當最糟的事情發生, 我愈騷擾他們,他們表現的愈是泰然自若; 然而較年輕且小的蟻群, 大約是兩歲左右,規模約二千隻工蟻的蟻群,相對而言則變化較大。 而最令人不敢相信的是這些工蟻的壽命只有一年, 可能是這年,也可能是那年, 所以在成熟蟻群看起來比較穩定的工蟻, 其實也沒有比年輕蟻群的工蟻老, 成熟蟻群的工蟻並不是有比較多的經驗或者更聰明, 相反的,一定是某種組織方式 會隨著蟻群成長而跟著改變, 最明顯的就是蟻群大小的改變。
So since I've had this result, I've spent a lot of time trying to figure out what kinds of decision rules -- very simple, local, probably olfactory, chemical rules could an ant could be using, since no ant can assess the global situation -- that would have the outcome that I see, these predictable dynamics, in who does what task. And it would change as the colony gets larger. And what I've found out is that ants are using a network of antennal contact. So anybody who's ever looked at ants has seen them touch antennae. They smell with their antennae. When one ant touches another, it's smelling it, and it can tell, for example, whether the other ant is a nest mate because ants cover themselves and each other, through grooming, with a layer of grease, which carries a colony-specific odor. And what we're learning is that an ant uses the pattern of its antennal contacts, the rate at which it meets ants of other tasks, in deciding what to do. And so what the message is, is not any message that they transmit from one ant to another, but the pattern. The pattern itself is the message. And I'll tell you a little bit more about that.
所以自從我知道了這樣的結果後,我花了很多時間試著去了解 螞蟻可能使用的方法,一定是簡單、局部、嗅覺或化學之類的法則, 因為沒有一隻螞蟻可以評估整體的狀況, 但他們卻表現出那種有效的組織方式。 而誰該做什麼工作,是可以預測的, 還會隨著蟻群成長而改變。 我所發現的是,工蟻是藉由觸角接觸來建立網路的, 看過螞蟻的人都知道它們會用觸角彼此接觸, 他們可以用觸角聞嗅氣味。 每當它們用觸角接觸,就是在聞味道, 而且這味道可以使彼此知道是自己人, 因為螞蟻會彼此利用梳毛的方式, 為對方覆蓋上一層具有蟻群獨特氣味的油脂。 而我們研究的便是螞蟻各種觸角接觸的模式, 從不同分隊的工蟻的觸角接觸頻率,可以決定它們該做什麼, 它們一隻接著一隻所傳送出去的內容, 並不是訊息,而是模式, 模式本身就是訊息, 我會再加以解釋。
But first you might be wondering: how is it that an ant can tell, for example, I'm a forager. I expect to meet another forager every so often. But if instead I start to meet a higher number of nest maintenance workers, I'm less likely to forage. So it has to know the difference between a forager and a nest maintenance worker. And we've learned that, in this species -- and I suspect in others as well -- these hydrocarbons, this layer of grease on the outside of ants, is different as ants perform different tasks. And we've done experiments that show that that's because the longer an ant stays outside, the more these simple hydrocarbons on its surface change, and so they come to smell different by doing different tasks. And they can use that task-specific odor in cuticular hydrocarbons -- they can use that in their brief antennal contacts to somehow keep track of the rate at which they're meeting ants of certain tasks. And we've just recently demonstrated this by putting extract of hydrocarbons on little glass beads, and dropping the beads gently down into the nest entrance at the right rate. And it turns out that ants will respond to the right rate of contact with a glass bead with hydrocarbon extract on it, as they would to contact with real ants.
但是一開始你們也許會想知道, 螞蟻是如何表明自己身分的,比如說我是覓食分隊的, 我會認為我遇到的應該都是覓食分隊的工蟻, 但是如果相反地,如果我開始遇到很多維護分隊的工蟻, 我現在就不太可能是在覓食。 所以我們必須知道如何分辨覓食分隊 與維護分隊之間的差異, 而我們已經知道的是,這種螞蟻-- 我懷疑其它種類的螞蟻也是一樣-- 覆蓋在螞蟻身上的油脂中的碳氫化合物, 會依不同任務的工蟻而有所不同。 從我們已經做的實驗顯示, 在外面待得愈久的螞蟻, 它們表皮上的碳氫化合物就會有愈大的改變, 所以他們會聞起來不一樣。 而這種來自表皮碳氫化合物的特定任務氣味, 在他們做短暫的觸角接觸時,會被用來 記錄他們與某個分隊工蟻的接觸速度, 這是我們最近才剛證實的。 我們把一些很小的玻璃珠沾上碳氫化合物, 以正確的速度把這些珠子輕輕的從蟻巢入口放入, 結果那些工蟻也以同樣的速度來回應接觸 那些沾有碳氫化合物的珠子, 就跟他們接觸其它真實的工蟻一般。
So I want now to show you a bit of film -- and this will start out, first of all, showing you the nest entrance. So the idea is that ants are coming in and out of the nest entrance. They've gone out to do different tasks, and the rate at which they meet as they come in and out of the nest entrance determines, or influences, each ant's decision about whether to go out, and which task to perform. This is taken through a fiber optics microscope. It's down inside the nest. In the beginning you see the ants just kind of engaging with the fiber optics microscope. But the idea is that the ants are in there, and each ant is experiencing a certain flow of ants past it -- a stream of contacts with other ants. And the pattern of these interactions determines whether the ant comes back out, and what it does when it comes back out. You can also see this in the ants just outside the nest entrance like these. Each ant, then, as it comes back in, is contacting other ants. And the ants that are waiting just inside the nest entrance to decide whether to go out on their next trip, are contacting the ants coming in.
我現在要播放一小段影片, 開始了,首先你看到的是蟻巢的入口, 這些螞蟻正從蟻巢的入口不斷地進進出出, 他們出去完成不同的任務,而當他們進出入口時, 他們接觸的速度會決定或影響 每一隻螞蟻的決定,看是否要出去執行什麼任務。 這是透過光纖顯微鏡所拍攝到的蟻巢內部, 一開始你會看到這些工蟻 好像對這光纖顯微鏡很感興趣, 但是我要讓你們看的是,那些工蟻 正持續地與它身旁竄流過去的工蟻們 源源不斷的相互接觸, 而這些互動的模式會決定 他們是否要再出去,以及出去做什麼。 你也可以在蟻巢的外面看到這些工蟻, 每一隻回來蟻巢的工蟻,正在與其它的工蟻做接觸; 而蟻巢入口處的工蟻則正在等待 這些剛回來的工蟻們,並與他們逐一接觸, 以決定是否前往下一個旅程。
So, what's interesting about this system is that it's messy. It's variable. It's noisy. And, in particular, in two ways. The first is that the experience of the ant -- of each ant -- can't be very predictable. Because the rate at which ants come back depends on all the little things that happen to an ant as it goes out and does its task outside. And the second thing is that an ant's ability to assess this pattern must be very crude because no ant can do any sophisticated counting. So, we do a lot of simulation and modeling, and also experimental work, to try to figure out how those two kinds of noise combine to, in the aggregate, produce the predictable behavior of ant colonies.
所以這個系統有趣的地方在於,它是亂無章法的, 它是變化無常的,尤其還有兩種不確定因子, 第一,每隻工蟻的經驗是不能夠預測的, 因為工蟻們回來時的速度 取決於他們在外面工作時,遭遇到的所有大小事; 第二,每隻工蟻僅能對這種模式做粗略的評估, 因為工蟻並不能夠做任何複雜的計數。 所以我們建立了很多模型來模擬,也做了很多實驗, 我們想試著去了解如何把這兩種不確定因子結合, 以產生可預期的蟻群集體行為。
Again, I don't want to say that this kind of haphazard pattern of interactions produces a factory that works with the precision and efficiency of clockwork. In fact, if you watch ants at all, you end up trying to help them because they never seem to be doing anything exactly the way that you think that they ought to be doing it. So it's not really that out of these haphazard contacts, perfection arises. But it works pretty well. Ants have been around for several hundred million years. They cover the earth, except for Antarctica. Something that they're doing is clearly successful enough that this pattern of haphazard contacts, in the aggregate, produces something that allows ants to make a lot more ants. And one of the things that we're studying is how natural selection might be acting now to shape this use of interaction patterns -- this network of interaction patterns -- to perhaps increase the foraging efficiency of ant colonies.
再一次強調,我不是說這種無秩序般的互動模式 可以製造出工廠般機械化的精準及效率, 事實上,如果你仔細觀察它們,你最後會想幫他們一把 因為它們的工作看起來總是 無法達到應有的水準, 所以這種無秩序的接觸方式,並不能完美的達成所有任務, 但是它仍然運作的不錯, 螞蟻已如此生存了數十億年, 除了南極洲,他們幾乎遍佈整個地球, 這代表他們一定有什麼過人之處, 能夠利用這種無秩序的接觸方式, 讓他們能夠繁衍出更多的螞蟻。 而我們正在研究的問題之一, 是大自然如何選擇塑造出這種互動模式, 如何塑造出這種 能讓蟻群的覓食效率提高的互動網路。
So the one thing, though, that I want you to remember about this is that these patterns of interactions are something that you'd expect to be closely connected to colony size. The simplest idea is that when an ant is in a small colony -- and an ant in a large colony can use the same rule, like "I expect to meet another forager every three seconds." But in a small colony, it's likely to meet fewer foragers, just because there are fewer other foragers there to meet. So this is the kind of rule that, as the colony develops and gets older and larger, will produce different behavior in an old colony and a small young one.
不過有件事我希望你們還記得, 就是這種互動的模式 是能夠隨著蟻群大小變化而有所調整的。 最簡單的例子,就是小蟻群中的工蟻 和大蟻群中的工蟻用的是同一種法則, 大蟻群中的工蟻,可能每三秒就會接觸一隻其它覓食分隊的工蟻, 而小蟻群中的工蟻,接觸的頻率則可能低的多, 只因為小蟻群的覓食分隊規模比較小, 所以這種法則在蟻群成長變大時, 蟻群的行為亦會跟著調適而有所不同。
Thank you.
謝謝。
(Applause)
(鼓掌)