VOA标准英语2014--美用黄蜂对抗甲虫入侵

 

Wasp¹ Recruited to Fight Invasive Beetle 美用黄蜂对抗甲虫入侵

Scientists are pitting insects against insects in a battle to control an invasive species.

U.S. Department of Agriculture researchers have released tiny parasitic² wasps³ in forests in Maryland to attack the emerald ash borer, an invader⁴ from China that is devastating⁵ forests across the northern United States.

By the end of this decade, this insect will have done an estimated $10 billion of damage nationwide, according to one study.

Plant and animal hitchhikers traversing the planet in our globalized economy have made invasive species a $1.4 trillion-a-year problem worldwide, says the United Nations.

But rather than spraying pesticides⁶ that risk doing additional harm, the USDA scientists are bringing the invasive insect’s natural predators⁷ in from Asia to try to restore balance.

Forests at risk

Beneath the bark of an infested⁸ ash tree, the borer’s larvae⁹ carve twisting paths that cut off the supply of nutrients¹⁰. It’s like slashing¹¹ the tree’s arteries¹².

"There is a possibility some species may be completely wiped out by this beetle,” said USDA entomologist Jian Duan. “And you can imagine the cascading¹³ effect of losing a tree species in our native forest."

Ash trees make up 20 to 40 percent of some northern U.S. forests. The emerald ash borer threatens them and all the creatures that depend on them.

When the borer arrived from China in the 1990s - likely in a wooden crate¹⁴ or shipping¹⁵ pallet - it had no natural enemies here.

Consorting¹⁶ with the enemy

In Asia, several species of parasitic wasps lay their own eggs inside borers’ eggs. The young wasps steal the developing borer's food, and the borer dies. Other wasps lay eggs in the larva itself. The eggs hatch and eat the larva alive as they grow.

It’s a grizzly¹⁷ but effective way to keep the emerald ash borer’s population in check.

So Duan is introducing these wasps to forests under attack.

Wasps are used successfully to control cassava mealybugs in Africa and many other invasive pests.

Quarantine

But Duan knows that fighting an invasive insect with another import can be risky¹⁸. It could become invasive, too.

So his lab raises wasps in quarantine while they're tested. He will only release picky eaters: wasps that would much rather attack an emerald ash borer than a native insect.

So far, Duan’s team has released three species of wasps. There are early signs that they are helping¹⁹ to slow the emerald ash borer’s advance. But they have a big job ahead of them.

While they have released several thousand wasps, one infested tree can produce hundreds of emerald ash borers. “It's really a drop in the ocean," Duan said.

"You have to think long-term,” he added.

Now Duan and his team will watch and wait to see if the wasps can return some balance to an ecosystem²⁰ at risk.

1 wasp   

n.黄蜂，蚂蜂

参考例句：

• A wasp stung me on the arm.黄蜂蜇了我的手臂。
• Through the glass we can see the wasp.透过玻璃我们可以看到黄蜂。

2 parasitic   

adj.寄生的

参考例句：

• Will global warming mean the spread of tropical parasitic diseases?全球变暖是否意味着热带寄生虫病会蔓延呢？
• By definition,this way of life is parasitic.从其含义来说，这是种寄生虫的生活方式。

3 wasps   

黄蜂( wasp的名词复数 )； 胡蜂； 易动怒的人； 刻毒的人

参考例句：

• There's a wasps' nest in that old tree. 那棵老树上有一个黄蜂巢。
• We live in dread not only of unpleasant insects like spiders or wasps, but of quite harmless ones like moths. 我们不仅生活在对象蜘蛛或黄蜂这样的小虫的惧怕中，而且生活在对诸如飞蛾这样无害昆虫的惧怕中

4 invader   

n.侵略者，侵犯者，入侵者

参考例句：

• They suffered a lot under the invader's heel.在侵略者的铁蹄下，他们受尽了奴役。
• A country must have the will to repel any invader.一个国家得有决心击退任何入侵者。

5 devastating   

adj.毁灭性的，令人震惊的，强有力的

参考例句：

• It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
• Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。

6 pesticides   

n.杀虫剂( pesticide的名词复数 )；除害药物

参考例句：

• vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜
• There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。 来自《简明英汉词典》

7 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

8 infested   

adj.为患的，大批滋生的（常与with搭配）v.害虫、野兽大批出没于( infest的过去式和过去分词 )；遍布于

参考例句：

• The kitchen was infested with ants. 厨房里到处是蚂蚁。
• The apartments were infested with rats and roaches. 公寓里面到处都是老鼠和蟑螂。

9 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

10 nutrients   

n.（食品或化学品）营养物，营养品( nutrient的名词复数 )

参考例句：

• a lack of essential nutrients 基本营养的缺乏
• Nutrients are absorbed into the bloodstream. 营养素被吸收进血液。 来自《简明英汉词典》

11 slashing   

adj.尖锐的；苛刻的；鲜明的；乱砍的v.挥砍( slash的现在分词 )；鞭打；割破；削减

参考例句：

• Slashing is the first process in which liquid treatment is involved. 浆纱是液处理的第一过程。 来自辞典例句
• He stopped slashing his horse. 他住了手，不去鞭打他的马了。 来自辞典例句

12 arteries   

n.动脉( artery的名词复数 )；干线，要道

参考例句：

• Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
• This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》

13 cascading   

流注( cascade的现在分词 )； 大量落下； 大量垂悬； 梯流

参考例句：

• First of all, cascading menus are to be avoided at all costs. 首先，无论如何都要避免使用级联菜单。 来自About Face 3交互设计精髓
• Her sounds began cascading gently. 他的声音开始缓缓地低落下来。

14 crate   

vt.(up)把…装入箱中；n.板条箱，装货箱

参考例句：

• We broke open the crate with a blow from the chopper.我们用斧头一敲就打开了板条箱。
• The workers tightly packed the goods in the crate.工人们把货物严紧地包装在箱子里。

15 shipping   

n.船运（发货，运输，乘船）

参考例句：

• We struck a bargain with an American shipping firm.我们和一家美国船运公司谈成了一笔生意。
• There's a shipping charge of ￡5 added to the price.价格之外另加五英镑运输费。

16 consorting   

v.结伴( consort的现在分词 )；交往；相称；调和

参考例句：

• He' d been consorting with known criminals. 他一直与那些臭名昭着的罪犯有交往。 来自辞典例句
• Mr. Berlusconi's wife publicly accused him of 'consorting with minors' and demanded a divorce. 贝卢斯科尼的妻子公开指责他“与未成年人交往”，并提出离婚。 来自互联网

17 grizzly   

adj.略为灰色的，呈灰色的；n.灰色大熊

参考例句：

• This grizzly liked people.这只灰熊却喜欢人。
• Grizzly bears are not generally social creatures.一般说来，灰熊不是社交型动物。

18 risky   

adj.有风险的，冒险的

参考例句：

• It may be risky but we will chance it anyhow.这可能有危险，但我们无论如何要冒一冒险。
• He is well aware how risky this investment is.他心里对这项投资的风险十分清楚。

19 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。

20 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。