【听力文摘】果蝇喜欢酒精!

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2013-11-12 11:02

【听力文摘】果蝇喜欢酒精!

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Fruit Flies Love Alcohol!

When human females are pregnant, they’re advised to stay away from alcohol, for fear of harming the fetus. And most parents refrain from giving their infants bottles full of whiskey or beer, for obvious reasons.

But if you’re a fruit fly, literally dousing your offspring in alcohol is apparently one of the best ways to protect them from danger, particularly from certain types of wasps.

How and why?

Let’s back up a bit. First, certain types of wasps prey on fruit flies by injecting eggs inside fruit fly larvae. Unless an infected larva kills the wasp egg, it hatches and the wasp larva eats its way out from inside the fruit fly larva, killing it.

One way for fruit fly moms to protect against this gruesome fate is to lay their eggs in an alcohol soaked environment, such as fermenting fruit, when they see that parasitic wasps are around. Although alcohol is toxic to fruit flies, it’s even more toxic to wasps, which, unlike fruit flies, have not evolved a high level of alcohol tolerance. So if the larvae eat enough alcohol rich food, it can kill the wasp egg and keep it from hatching.


Protecting young

Apparently, fruit flies are not the only fly species to use alcohol to protect their young. In fact, it seems that most flies that eat rotting fruit use the alcohol defense against wasps. So fruit flies are not unique in this regard, but they’re still mighty impressive.

果蝇喜欢酒精!

当人类女性怀孕时,人们就会建议她们戒酒,以免伤害胎儿。大多数父母都不会给婴儿接触满瓶的威士忌或者啤酒,原因是显而易见的。

但如果你是一只果蝇,毫不夸张的说,你把后代浸没在酒精中是保护它们远离危险的最好办法之一,特别是这样能避免黄蜂的伤害。

如何以及为什么要这样做?

让我们来回顾一下。首先,特定类型的黄蜂会将卵注入果蝇幼虫中,以捕食果蝇。除非受感染的果蝇幼虫杀死黄蜂卵,否则当黄蜂卵孵化出来后,黄蜂幼虫将会由内而外吞噬果蝇幼虫,将其杀死。

果蝇妈妈为防止幼虫遭受厄运的其中一种办法是,当看到寄生蜂的出现时,将卵产在酒精浸泡的环境之中,例如发酵的水果里。尽管酒精对果蝇有毒,但酒精对黄蜂的毒性更大。与果蝇不同,黄蜂还没有进化成对高浓度酒精的耐受性。所以如果果蝇幼虫吃了足够富含酒精的食物后,它就可以杀死黄蜂卵并使之不能孵化。

保护果蝇幼虫

很明显,果蝇并不是利用酒精来保护幼虫的唯一的蝇类。实际上,大部分的苍蝇都会食用腐烂水果,利用酒精来防御黄蜂。所以果蝇在这方面并不独特,但它们仍然令人印象深刻。

【本译文由普特网友 virtue8591 提供】