評論
打印
You are pretty close, actually, the caterpillars have a honey gland, an organ that secretes an amino acid and carbohydrate liquid.
你已經很接近了，事實上，毛毛蟲有一個蜜腺，一種能分泌氨基酸和液態糖的器官。
The caterpillars secretes the liquid from the honey gland, rather large quantities, enough to feed several ants.
毛毛蟲從蜜腺中分泌出大量液體，足夠喂飽好幾只螞蟻。
But what makes this relationship obligatory for the caterpillar?
但是這種關系對毛毛蟲來說為什么是強制性的呢？
Well, if the ants don’t feed regularly on the liquid from the caterpillar’s honey gland, the gland overloads and gets infected.
如果螞蟻不定期吃掉毛毛蟲從蜜腺中分泌出的液體，蜜腺就會負荷過重，受到感染。
The infection will kill the caterpillar and it’ll never reach its final stage of development, becoming a butterfly. John?
這種感染對毛毛蟲來說是致命的，它永遠也無法成長到進化的最后階段變成一只蝴蝶了，John，請說？
OK, I just want to make sure I’m following here, the caterpillar needs the ants or it won’t make it to the stage where it can become a butterfly.
我只是想確認一下我聽懂了，毛毛蟲需要螞蟻，否則就活不到進化成蝴蝶的階段了。
And the ants do this because they get an easy meal out of it, right?
而螞蟻這么做是因為它們能從中獲得白吃的午餐，對嗎？
But the ants don’t absolutely need the caterpillar for survival, ‘cause they can get food from other places, right?
但是螞蟻不是絕對需要毛毛蟲才能生存啊，因為它們能從其他地方弄到食物，不是嗎？
So it’s still called mutualism even though it seems like the caterpillar’s getting way more out of it.
所以這種關系仍被稱為互惠共生，即使看起來毛毛蟲獲得的利益比較多。
Oh, wait, you said they don’t have to equally benefit. Never mind, sorry.
啊，等一下，你說過它們得到的不一定是同等的好處，不好意思，忘記我說過的話吧。
Yes. But there is a type of mutualism where the relationship is necessary for both organisms to survive.
是的，但是有一種類型的互惠共生關系對兩種生物來說都是生存必需的。
It’s called obligatory mutualism. And we’ll talk about that in the next class.
它叫做義務性共生，我們下節課再講。
