自然界真的是非常神奇的存在，小托福的考试中有一篇听力讲到了这种蚂蚁 - leafcutter ants （切叶蚁），当时听的时候知道它会切叶子，但是今天才知道它会和真菌合作，互利互惠。非常有意思。
Leucoagaricus（白环菇属真菌). It's neither animal nor plant. It's a fungus. It lives five meters underground, far from the leaves that it devours. (Devour 这个词用的可真好，把这个真菌的贪婪的特性体现的淋漓尽致）
To get them, it employs the best leaf-gatherers in the tropics - leafcutter ants. Millions of them provide the fungus with its food, and , in return, the fungus cultivates tiny mushrooms as food for the ants.
The fungus releases chemical signals that tell the worker ants what type of leaf it wants to eat. Scouts are sent out with the latest orders. Worker ants will travel hundreds of meters to find the right kind.
The pieces are carried back to the underground fungus. The ants can run at speeds of two meters a minute. And each can carry a load ten times of its own weight. To avoid congestion, worker ants dig trenches around obstacles.
Fed by such a continuous supply, the fungus grows rapidly, filling the chambers in which it lives. So, the ants excavate more space.
It seems that the tree will not survive, but it fights back...using chemical warfare. The tree floods its leaves with toxins that could kill the distant fungus. As the ants carry the fragments back they are, themselves, poisoning the fungus on the tree's behalf. It's a long distance attack!
As the poison takes effect, the ants sense that their fungus is weakening... and they respond to its signals by changing to another source of leaves. So the plant's chemical response forces the ants to constantly switch from tree...to tree.
Strike... and counterstrike. （我很喜欢这句话）
