科學(xué)60秒:嚇?biāo)阑蛘弑怀缘簦?/h1>
來源:滬江聽寫酷
2011-11-30 10:00
A hungry fish can kill prey with a quick bite. [ 1 ]. 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]
[ 2 ]. 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 [ 3 ], compared to counterparts living in predator-free waters. [ 4 ], too.
The authors suggest a couple reasons why. First, [ 5 ]. 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.
[ 6 ].
【視聽版科學(xué)小組榮譽(yù)出品】
- 相關(guān)熱點(diǎn):
- 品牌聽力
- 英語口語學(xué)習(xí)