本文选自《经济学人》8月8日刊文章。昆虫可以说是陆地霸主，陆地上已发现的昆虫约有100万种，未发现的数量预计是这一数字的几倍，但是昆虫在海洋中却很罕见，不过也有例外，寄生在海豹身上的虱子就可以在海里生存，可以忍受海洋中各种化学物质的侵蚀，承受巨大水压。但是海豹虱子毕竟是个例，是什么让昆虫在进化过程中远离海洋，仍然是一个谜。
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Parasites under pressure 深海下的寄生虫An exception to the rule that there are no marine insectsLice that latch onto seals survive deep-sea rides
INSECTS DOMINATE dry land. About 1m species have been described, more than twice as many as all other multicellular animal species, terrestrial and marine, put together. Several times that number are reckoned to await discovery. The oceans, though, are mostly insect-free. A few skate over the surface, but none dive willingly below the waves.昆虫称霸陆地，已被描述的昆虫物种大约有100万种，是陆地和海洋所有其他多细胞动物物种总和的两倍多，而有待被发现的昆虫数量是这个数字的几倍。然而，海洋大部分是没有昆虫的。一些昆虫滑行在水面上，但没有昆虫会潜到海浪下面。At least, that was the consensus until recently. But Soledad Leonardi at CONICET-CENPAT in Argentina and Claudio Lazzari at the University of Tours, in France, have found an exception: the 13 species of lice that latch onto seals. That seals have lice is not news. But Dr Leonardi and Dr Lazzari have shown that, contrary to previous belief, these passengers do not abandon ship, as it were, and remain on dry land when the seals go swimming. Instead, they cling on and brave not only the hostile, saline chemistry of seawater, but also the tremendous pressures imposed when their hosts dive to depths of several hundred metres in search of prey.至少直到最近人类依然这样认为。但是，阿根廷CONICET-CENPAT的Soledad Leonardi和法国图尔大学的Claudio Lazzari发现了一个例外：寄生在海豹身上的13种虱子。海豹身上有虱子已经不是什么新闻了。但是Leonardi和Lazzari博士指出，与之前的观点截然不同的是，这些昆虫并没有在海豹潜入海里时离开海豹，留在陆地，相反，它们仍然在海豹身上，不仅勇敢地面对不利于生存的、含盐的海水，还要在它们的宿主潜入几百米深处寻找猎物时，承受的巨大压力。Dr Leonardi and Dr Lazzari disposed of the salinity question in 2014 by the simple procedure of dunking seal lice in seawater for prolonged periods, and discovering that they did not die. Now, as they report in the Journal of Experimental Biology, they have dealt with the question of pressure.
2014年，Leonardi和Lazzari博士将海豹虱子长时间浸泡在海水中，并发现它们没有死亡，通过这个简单方法解决了（海豹虱子的）盐度问题。现在，正如他们在《实验生物学杂志》上报告的那样，他们已经解决了（海豹虱子的）压力问题。
