《经济学家》读译参考013-016期.docVIP

（13）：一路繁衍——你知道外来入侵物种吗？ Mar 2nd 2006From The Economist print edition[size=4]Go forth and multiply 一往无前，生生不息 WHAT makes for a successful invasion? Often, the answer is to have better weapons than the enemy. And, as it is with people, so it is with plants—at least, that is the conclusion of a p_______① published in ★Biology Letters[1] by Naomi Cappuccino, of Carleton University, and Thor Arnason, of the University of Ottawa, both in Canada.怎样才能成功入侵？答案常常是 :拥有比敌人更好的武器。人是这样，植物也是如此——至少，《生物书简》上发表的一篇论文是这么认为的，作者是来自加拿大加里敦大学的纳奥米?卡普奇诺和渥太华大学的索尔?阿纳森。The phenomenon of alien species ★popping up[2] in unexpected parts of the world has grown over the past few d________② as people and goods become more mobile and （1）?plant seeds and animal larvae have hitched[3] along for the ride?. Most such aliens blend into the ecosystem in which they arrive without too much fuss. (Indeed, many probably fail to establish themselves at all—but those failures, of course, are never noticed.) Occasionally, though, something ★goes bananas[4] and starts trying to take the place over, and an invasive species is born. Dr Cappuccino and Dr Arnason asked themselves w_______③.过去的几十年，随着人和货物的流动日益频繁，植物种子和动物幼体也乘机“搭便车”四处播散，世界各地无意间出现了越来越多的外来物种。这些外来物种大多数都轻而易举地融入了所到之处的生态系统。（事实上，许多物种可能还没有站稳脚跟——当然，人们从未注意到这一点。）不过，偶尔也有某些物种疯狂繁殖，开始企图占领原有物种的生长空间，一种入侵物种就这样形成了。卡普奇诺和阿纳森对此感到百思不得其解。One hypothesis is that aliens leave their predators b________. Since the predators in their new homelands are not adapted to exploit them, they are able to reproduce unchecked. That is a nice idea, but it does not explain why only certain aliens become invasive. Dr Cappuccino and Dr Arnason suspected this might be because native predators are [b]（2）?sometimes “pre-adapted” to the aliens defenses?, but in other cases they are not.有人推想，外来物种摆脱了原先的掠食者，而在新的“家园”，现有的掠食者又没有发现它们也合口味，因此这些物种得以肆无忌惮地繁衍。这种观点好是好，不过没有解释为什么只有特定的外来物种才具有入侵性。卡普奇诺和阿纳森猜测，这可能是因为土生土长的掠食者对外来物种所具有的防御机制有时产生“预适应”，有时又不产生。To test this, they had first to establish a reliable list of in