13英語閱讀-經(jīng)濟(jì)學(xué)人《Economics》雙語版-Go forth and multiply.docx

經(jīng)濟(jì)學(xué)家讀譯參考（第13篇）：一路繁衍你知道外來入侵物種嗎？Go forth and multiply一往無前，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 plantsat least, that is the conclusion of a p_ published in Biology Letters1 by Naomi Cappuccino, of Carleton University, and Thor Arnason, of the University of Ottawa, both in Canada.怎樣才能成功入侵？答案常常是：擁有比敵人更好的武器。人是這樣，植物也是如此至少，生物書簡上發(fā)表的一篇論文是這么認(rèn)為的，作者是來自加拿大加里敦大學(xué)的納奧米卡普奇諾和渥太華大學(xué)的索爾阿納森。 The phenomenon of alien species popping up2 in unexpected parts of the world has grown over the past few d_ as people and goods become more mobile and （1）plant seeds and animal larvae have hitched3 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 allbut those failures, of course, are never noticed.) Occasionally, though, something goes bananas4 and starts trying to take the place over, and an invasive species is born. Dr Cappuccino and Dr Arnason asked themselves w_.過去的幾十年，隨著人和貨物的流動(dòng)日益頻繁，植物種子和動(dòng)物幼體也乘機(jī)“搭便車”四處播散，世界各地?zé)o意間出現(xiàn)了越來越多的外來物種。這些外來物種大多數(shù)都輕而易舉地融入了所到之處的生態(tài)系統(tǒng)。（事實(shí)上，許多物種可能還沒有站穩(wěn)腳跟當(dāng)然，人們從未注意到這一點(diǎn)。）不過，偶爾也有某些物種瘋狂繁殖，開始企圖占領(lǐng)原有物種的生長空間，一種入侵物種就這樣形成了?？ㄆ掌嬷Z和阿納森對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 defences, but in other cases they are not.有人推想，外來物種擺脫了原先的掠食者，而在新的“家園”，現(xiàn)有的掠食者又沒有發(fā)現(xiàn)它們也合口味，因此這些物種得以肆無忌憚地繁衍。這種觀點(diǎn)好是好，不過沒有解釋為什么只有特定的外來物種才具有入侵性?？ㄆ掌嬷Z和阿納森猜測，這可能是因?yàn)橥辽灵L的掠食者對外來物種所具有的防御機(jī)制有時(shí)產(chǎn)生“預(yù)適應(yīng)”，有時(shí)又不產(chǎn)生。 To test this, they had first to establish a reliable list of invaders. That is not as easy as it sounds. As they observe, “although there are many lists of invasive species published by governmental agencies, inclusion of a given species in the lists （3）may not be entirely free of political motivation”. Instead, they polled established researchers in the field of alien species, asking each to list ten invasive species and, for c_, ten aliens that just rubbed along quietly with5 their neighbours. The result was a list of 21 species widely agreed to be invasive and, for comparison, 18 non-invasive aliens.為了證實(shí)這一猜測，他們必須首先列出一些已經(jīng)確認(rèn)的入侵物種。這可不是件輕松的事。正如他們所說，“雖然政府部門公布了許多入侵物種名單，但是把指定物種歸入此名單也許多少有些出于政治上的考慮?！睘榇耍麄冋{(diào)查了外來物種領(lǐng)域一些有名望的研究人員，請每人舉出10種入侵物種，以及10種與本地物種能和睦共生的外來物種用于對照。最后得到的名單中包括21種被廣泛認(rèn)可的入侵物種和18種用于對照的非入侵性外來物種。 H_ established these lists, they went to the library to find out what was known about the plants chemistry. Their aim was to find the most prominent chemical weapon in each plant, whether that weapon was directed against insects that might want to eat the plant, bacteria and fungi that might want to i_ it, or other plants that might compete for space, water, nutrients and light. Botanists know a lot about which sorts of compounds have what roles, so classifying constituent chemicals in this way was not too hard.名單確定之后，他們就到圖書館查詢這些植物的化學(xué)性質(zhì)，旨在找出每種植物所擁有的作用最為突出的“化學(xué)武器”。這種“化學(xué)武器”的攻擊對象包括可能吃掉該植物的昆蟲，使其感染的細(xì)菌和真菌以及與其競爭生長空間、水、養(yǎng)料和陽光的其它植物。植物學(xué)家對哪些化合物有哪些作用都了如指掌，因此這樣對化學(xué)物質(zhì)進(jìn)行分類并不太難。 The researchers then compared the chemical arsenals of their aliens with those of native North American plants, （4）to see if superior (or, at least, unusual) weaponry was the explanation for the invaders success. Their hypothesis was that highly invasive species would have chemical weapons not found in native plants, and w_ pests, parasites and other plants would therefore not have evolved any resistance to. The more benign aliens, by contrast, were predicted to have arsenals also found in at least some native species.然后，為了弄清外來物種的成功入侵是否得益于“超級武器“（或者至少是超常武器），這兩位研究人員將已知外來物種的“化學(xué)武器庫”同北美土生土長的植物“化學(xué)武器庫”進(jìn)行了比較。他們推斷，具有高度入侵性的物種擁有土產(chǎn)植物所缺少的“化學(xué)武器”，對這種化學(xué)武器，害蟲、寄生蟲及其它植物都不能產(chǎn)生任何抵抗力。相比之下，入侵性較弱的外來物種所具有的“武器庫”可能至少同樣存在于某些土產(chǎn)物種。 And so it proved. More than 40% of the invasive species had a chemical unknown to native plants; just over 10% of the non-invasive aliens had such a chemical. M_, when they looked at past studies on alien plants that had examined how much such plants suffer from the depredations6 of herbivorous insects, they found that the extent of the damage reported was significantly correlated with the number of native species with which that alien shared its principal chemical weapon.猜測因而得到了證實(shí)。40%以上的入侵物種含有一種土產(chǎn)植物所沒有的化學(xué)物質(zhì)，僅10%多一點(diǎn)的非入侵外來物種含此物質(zhì)。而且，他們在看了以前一些關(guān)于外來物種的研究（已經(jīng)查實(shí)這類植物受食草昆蟲的損害程度）之后，發(fā)現(xiàn)損害程度與土產(chǎn)植物的數(shù)量密切相關(guān)，而外來物種所含的主要“化學(xué)武器” 與這些土產(chǎn)植物相同。 For alien plants, then, the real secret of successalso as in human warfareis surprise. （5）It is not that the chemicals concerned are more toxic in any general sense (indeed, successful invaders are often rare in their own native habitats). R_, it is that the locals just dont see them coming.那么，對于外來植物而言，其成功的真正秘訣人的競爭也是如此令人感到驚奇，它不在于一般意義上所認(rèn)為的那樣具有毒性更強(qiáng)的化學(xué)物質(zhì)（的確，入侵成功的外來物種在其原有生長區(qū)域內(nèi)往往很罕見），而是因?yàn)楸镜芈邮痴吒緵]有察覺它們的到來。 NOTES：1Bilology Letters 生物書簡雜志 2pop up =happen suddenly, arise 突然出現(xiàn)，突然發(fā)生3hitch v.搭便車：He hitched across Europe.他搭便車橫跨歐洲。/Lets hitch a ride.讓我們搭一次便車。4go bananas （口語）發(fā)瘋，神經(jīng)錯(cuò)亂辨析top banana 與 go bananas top banana 本指喜劇的主角（ chief comic ），現(xiàn)在多半都指老板或上司（ boss or supervisor ）。 例如： He is a top banana in this corporation. （他是公司的老板。） 但是 go bananas 系指激動(dòng)、瘋狂、神魂顛倒（ wild, crazy or excited ）（ banana 要用復(fù)數(shù)。） 例如： The drugs （ marijuana ） have made him go bananas. （毒品大麻使他神魂顛倒。） 此外， to drive （ someone ） bananas （或 nuts ）意思也是使人發(fā)狂，只是動(dòng)詞要用 drive, banana 也要用復(fù)數(shù)。 例如： He has driven his wife bana