VOA标准英语2012--Plants Weaken Without Insects Bugging Them
时间：2019-01-14 作者：英语课 分类：VOA标准英语2012年(十月)
Plants Weaken Without Insects Bugging 2 Them
Evolutionary 3 pressures
The new study examines how insects and plants are still co-evolving.
Anurag Agrawal studies evolution in real-time. The Cornell University professor of ecology and evolutionary biology set up experimental plots of evening primrose 4 to observe the evolutionary pressures that insects continue to put on the wildflower.
“We took insects out of the picture for half of the plots, using an insecticide, and we then watched the evolutionary change that happened in those plant populations,” said Agrawal.
Agrawal and colleagues were surprised by what they saw. In their five-generation, five-year study reported in Science, evidence for evolutionary change began showing up quickly, after just two or three years.
“When we take insects out of the picture, essentially 5 the plants were less resistant 6. In other words, they evolved in the direction we expected them to," Agrawal explained. "If they are not experiencing the pressure of insect pests, they were flowering earlier and producing less toxins 7 so they become essentially less resistant.”
Losing their resistance
In other words, plants that enjoyed chemical pest protection lost some of their natural bug 1 resistance, compared to plants that were not sprayed.
Agrawal says he and his team were also surprised to discover that the speedy adaptation of the primrose to a bug-free environment triggered other changes in the local ecology. “And that had to do with the other species that were competing with our evening primroses 8,” he said.
Such as dandelions, whose population doubled over the five years, reducing the number of primroses.
“The suppressing of the insects favored the dandelions,” Agrawal added.
Most plants naturally produce defensive 9 toxins to ward 10 off insect attacks. But in today’s high-yield farming systems, growers have strong incentives 11 to use powerful chemical sprays to keep pest populations under control.
Natural balance
Agrawal's study suggests farmers should consider ways to strike a more natural balance between crops and bugs 12.
“I think that what it tells us is that insects are really important, that over the millennia 13 plants have figured out ways to co-exist with their pests and that when we perturb 14 that system in any way, there are likely to be a set of consequences, some of which we can predict and others we can’t,” he says.
The researchers plan to maintain their experiment as a living, learning laboratory to track evolutionary changes over the coming decades.
- There is a bug in the system.系统出了故障。
- The bird caught a bug on the fly.那鸟在飞行中捉住了一只昆虫。
- Okay, then let's get the show on the road and I'll stop bugging you. 好，那么让我们开始动起来，我将不再惹你生气。 来自辞典例句
- Go fly a kite and stop bugging me. 走开，别烦我。 来自英汉 - 翻译样例 - 口语
- Life has its own evolutionary process.生命有其自身的进化过程。
- These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
- She is in the primrose of her life.她正处在她一生的最盛期。
- The primrose is set off by its nest of green.一窝绿叶衬托着一朵樱草花。
- Really great men are essentially modest.真正的伟人大都很谦虚。
- She is an essentially selfish person.她本质上是个自私自利的人。
- Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
- They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。
- The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
- Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》
- Wild flowers such as orchids and primroses are becoming rare. 兰花和报春花这类野花越来越稀少了。 来自《简明英汉词典》
- The primroses were bollming; spring was in evidence. 迎春花开了，春天显然已经到了。 来自互联网
- Their questions about the money put her on the defensive.他们问到钱的问题，使她警觉起来。
- The Government hastily organized defensive measures against the raids.政府急忙布置了防卫措施抵御空袭。
- The hospital has a medical ward and a surgical ward.这家医院有内科病房和外科病房。
- During the evening picnic,I'll carry a torch to ward off the bugs.傍晚野餐时，我要点根火把，抵挡蚊虫。
- tax incentives to encourage savings 鼓励储蓄的税收措施
- Furthermore, subsidies provide incentives only for investments in equipment. 更有甚者，提供津贴仅是为鼓励增添设备的投资。 来自英汉非文学 - 环境法 - 环境法
- All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
- The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》
- For two millennia, exogamy was a major transgression for Jews. 两千年来，异族通婚一直是犹太人的一大禁忌。
- In the course of millennia, the dinosaurs died out. 在几千年的时间里，恐龙逐渐死绝了。