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詼諧的語(yǔ)言，生動(dòng)的內(nèi)容一分鐘快速掌握科技最新動(dòng)態(tài)

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本期節(jié)目音頻下載

Invading Species Carrying Parasites Have Healthy Appetites

Invasive species can decrease biodiversity and drive resident species to the brink of extinction. But how do these interlopers fare so well in unfamiliar territory? One idea is that they’ve escaped their enemies, for example, the parasites that keep them in check on their home turf. But a study in the journal Biology Letters [Jaimie Dick et al., RRRl] suggests that notion doesn’t always stand up. Because at least one kind of invasive shrimp is an even bigger pest when it has a parasite on board.

外來(lái)物種入侵會(huì)減少生物多樣性并可能致使當(dāng)?shù)匚锓N滅絕。不過(guò)這些外來(lái)物種在完全陌生的環(huán)境當(dāng)中怎么會(huì)這么為所欲為的呢？有人認(rèn)為，陌生的環(huán)境中缺少這些外來(lái)物種的天敵，比如說(shuō)抑制他們生長(zhǎng)的寄生物。但《生物學(xué)快報(bào)》中一文則指出這一觀點(diǎn)并非恒成立——至少有一種蝦類，當(dāng)被寄生物寄生時(shí)，生長(zhǎng)不受抑制不說(shuō)，危險(xiǎn)系數(shù)還反而增加了。

The scientists were studying a freshwater shrimp commonly found in England. Fishermen brought the shrimp to Northern Ireland in the 1950s as a tasty treat for local trout. Well, the shrimp liked the new digs. So much that they’ve all but eliminated the native shrimp species. The strange thing is, they may have parasites to thank.

科學(xué)家們對(duì)一種英格蘭常見(jiàn)的淡水蝦進(jìn)行了研究。20世紀(jì)50年代，漁民們把這些鱒魚的美味佳肴帶到了北愛(ài)爾蘭，這些淡水蝦倒是很樂(lè)意，不過(guò)土生土長(zhǎng)的小蝦可就大難臨頭了。但奇怪的是，在其中扮演微妙角色的竟是那些寄生生物。

In some streams, 70 percent of the invaders are infected with an intestinal worm that doesn’t go for the native shrimp. But this gut worm doesn’t slow them down. In fact, infected shrimp eat 30 percent more prey than those that are parasite-free.

在某些河流中，有70%的英格蘭淡水蝦被一種腸蟲(chóng)寄生，當(dāng)?shù)匚r則未被寄生。而這些寄生蟲(chóng)不但沒(méi)有抑制寄主們生長(zhǎng)，反而讓寄主們胃口大開(kāi)，要比未被寄生多吃30%。

Which perhaps is not surprising. If you had a worm that constituted a quarter of your body weight, you’d eat more too.

這聽(tīng)起來(lái)可能沒(méi)什么，不過(guò)想想看，要是也有條是你體重四分之一的蠕蟲(chóng)寄居在你體內(nèi)的話，那你肯定也會(huì)大吃特吃的。

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