Scientists think more than 200 different forms of parasitism have evolved independently from one another.

科学家们认为地球上有两百多种不同的寄生现象，它们彼此独立进化而来。

Many interactions are considered parasitism because the benefit to one species comes at a cost to the other.

许多相互作用被认为是寄生，因为一个物种的利益是以另一个物种的代价为代价的。

I mean, even pregnancy could be thought of as parasitism.

我的意思是， 甚至怀孕都可以被认为是寄生虫。

Brood parasitism tends to evoke horror and disdain.

育雏寄生往往会引起恐惧和蔑视。

While brachiopods with tubes were smaller, Leung says, this might not be due to parasitism.

梁说，虽然带管的腕足动物较小， 但这可能不是由于寄生。

This is probably because, before brood parasitism appeared, responding would have likely had no adaptive value.

这可能是因为，在巢寄生现象出现之前，反应可能没有适应性价值。

Most birds build nests, but several different families of birds evolved what is called brood parasitism, where females lay eggs in another individual's nest.

大多数鸟类筑巢，但几个不同的鸟类科进化出所谓的育雏寄生，雌性在另一个单独的巢中下蛋。

Moreover, the marriage insurance condemns her to life-long dependency, to parasitism, to complete uselessness, individual as well as social.

此外，婚姻保险使她终身依赖、寄生、完全无用， 无论是个人还是社会。

Whichever way you swing it, brood parasitism is yet another example of the fascinating turns evolution has taken.

无论你如何摆弄它，育雏寄生都是进化所发生的令人着迷的转变的又一个例子。

But in the most egregious cases of brood parasitism, why don't host parents take a stand?

但在最恶劣的寄生虫案例中，为什么寄宿父母不表态呢？