?

一分鐘音頻，有趣又省時(shí)：

>>下載本期科學(xué)60秒<<

A hungry fish can kill prey with a quick bite. That is, of course, if its prey hasn't already died of fright. Take tasty dragonflies. The mere presence of predators—even caged ones—is enough to scare dragonflies to death, according to a study in the journal Ecology. [Shannon J. McCauley, Locke Rowe, and Marie-Josée Fortin, The deadly effects of ‘nonlethal’ predators]
一條饑餓的魚(yú)能在瞬間咬住并殺死獵物。當(dāng)然，前提就是它的獵物還沒(méi)被嚇?biāo)纞蜻蜓也許很美味吧。它們的捕食者剛一出現(xiàn)，即使是被關(guān)在籠子里，好吧，也足以嚇?biāo)肋@些小生物了~這是根據(jù)一項(xiàng)生態(tài)學(xué)雜志上的最新研究得出的結(jié)論。

Researchers collected wild dragonfly larvae, and placed them in tanks with fish or insect predators. The larvae could see and smell their hunters—but were kept safe by underwater cages. After two months, the researchers took a head count—and found that dragonfly larvae sharing quarters with their killers were two to four times as likely to die off, compared to counterparts living in predator-free waters. And they had slimmer chances of surviving metamorphosis, too.
研究人員們采集了野生蜻蜓的幼蟲(chóng)，把它們與 魚(yú)類或食昆蟲(chóng)的生物們放在一起飼養(yǎng)。這些幼蟲(chóng)能看到、聞到它們周圍的敵人，但是其實(shí)彼此還是被水中的容器間隔著，相安無(wú)事。兩個(gè)月之后，研究人員們重新計(jì)數(shù)，結(jié)果發(fā)現(xiàn)，與天敵放在一起的這些幼蟲(chóng)全部死亡的時(shí)間（我認(rèn)為也就是它們的壽命吧）提前了2到4倍，對(duì)照組的幼蟲(chóng)們是生活在沒(méi)有天敵存在的水容器中。除此之外，它們變?yōu)槌上x(chóng)的幾率也顯著降低了。

The authors suggest a couple reasons why. First, prey tend to make fewer forays for snacks when predators are lurking around, so they may not be as nutritionally fit. And previous studies have shown that the presence of predators ups stress levels in prey, weakening their immune systems and making them more vulnerable to disease—and death.
該項(xiàng)研究的作者提出了幾個(gè)解釋的原因。首先，獵物由于周圍有天敵的游蕩因此很少有勇氣自身活動(dòng)范圍而找尋食物，因此也許它們就比正常情況缺乏營(yíng)養(yǎng)。最近的研究已經(jīng)顯示，天敵出現(xiàn)會(huì)增加獵物們的生存壓力水平，進(jìn)而減弱它們的免疫系統(tǒng)，并使它們更容易患病，從而死去~~

As if being eaten wasn't enough to worry about, looks can kill too.
也許一口就被吃掉反而不那么可怕，目光也一樣能殺死人啊~ ?

是否喜歡這個(gè)廣受歡迎的節(jié)目呢？那就別猶豫啦～點(diǎn)擊下圖訂閱吧～已有3.7萬(wàn)滬友訂閱了哦～

或者訂閱我的相關(guān)節(jié)目