VOA慢速英语：蚂蚁是如何生存和选择自己的领袖 2014-06-26

How Ants Survive and Choose Their Leader

Scientists have always been interested in the high level of organization in ant societies. American researchers have watched ants build life-saving rafts to keep afloat during floods. They also have documented how ant colonies choose their next queen – the female whose job is to produce eggs.

New technology is helping to improve researchers’ understanding of the insects. But there is still a lot to be learned.

Fire ants living in Brazilian forests are perfectly at home in an environment where flooding is common. To save themselves, the insects connect their legs together and create floating rafts. Some ant rafts can be up to 20 centimeters wide.

David Hu is a mechanical engineer with the Georgia Institute of Technology, also known as Georgia Tech. He says ants know how to join together tightly.

“If you have 100 ants, which means 600 legs, 99 percent of those legs will be connected to a neighbor. So they’re very, very good at maintaining this network.”

David Hu and other Georgia Tech researchers wanted to study ants and the secret of their engineering. They froze ant rafts and then look at them with the help of computed technology, or CT, images.

The pictures showed that larger ants serve in central positions to which smaller ants hold. The larger ants form pockets of air that keep the insects afloat.

Scientists say small robots or materials that can change shape could be programmed in a similar way, working towards a shared goal.

Researchers at North Carolina State University are also studying ants. They examined how Indian jumping ants choose the leader of the colony when they lose their top female or queen.

Researcher Clint Penick says all the worker ants in the colony are females. His team found that the work ants start a series of competitions or battles. The team found that some workers became physically larger and that led to the release of chemicals in the insects.

“Within a matter of days, we see changes in dopamine in the brain that we think are linked to the reproduction that starts in these workers.”

Soon, the winning ant starts developing ovaries, the organs required to produce eggs, while its brain decreases in size. The winning ant also begins standing taller and generally lives three times as long as the other ants.

Scientists say this behavior and the release of neural hormones are the result of genetic orders. Scientists say the new findings may help researchers better understand the link between hormones and genes in human beings.

I’m Bob Doughty.

词汇解析

candidate

难度：4星核心词汇，属常用3000词

英汉解释

n.候选人;应试者

参考例句

用作名词 (n.)

He made several favorable comments about their candidate.

他对他们的候选人发表了一些有利的评论。

Most candidates passed in grammar.

参加考试的人大多数语法及格。

obvious

难度：4星核心词汇，属常用3000词

英汉解释

adj.明显的;显然的

参考例句

用作形容词 (adj.)

It is obvious that she is very clever.

很明显，她挺聪明。

bitterly

英汉解释

adv.残酷地;痛苦地

参考例句

用作副词 (adv.)

It is bitterly cold today.

今天冷得很。

flee

难度：4星核心词汇，属常用3000词

英汉解释

vi.逃走;消失;逃避;(时间)飞逝

vt.逃离

参考例句

用作不及物动词 (vi.)

He tried to flee from the police in a stolen car.

他企图驾驶一辆偷来的车从警察局逃走。

He should not flee from responsibility.

他不应逃避责任。

用作及物动词 (vt.)

Many refugees have been forced to flee their homeland.

很多难民被迫逃离了祖国。

pressure

难度：5星基本词汇，属常用1000词

英汉解释

n.压强;压力;压迫

v.施压

参考例句

用作名词 (n.)

The tooth became sore to pressure and there is a dull gnawing pain.

该齿对于压迫作痛，且有钝麻如咬的疼痛。

用作动词 (v.)

Don't be pressured into making any rash decisions.

不要在施压下做出轻率的决定。

slave

难度：4星核心词汇，属常用3000词

英汉解释

n.奴隶;像奴隶般受制的人;【机】从动装置

v.做苦工;做奴隶;拼命干

参考例句

用作名词 (n.)

This slave dreamed of becoming a freeman.

这个奴隶梦想着成为一个自由人。

用作动词 (v.)

Why should I slave away all my life !

我为什么要辛辛苦苦地干一辈子呀!

spread

难度：5星基本词汇，属常用1000词

英汉解释

v.传播;展开;散布;铺开;伸展;涂撒

n.范围;传播;差额;幅度;盛宴

参考例句

用作动词 (v.)

The radio spread the news as soon as the accident happened .

事故一发生,收音机就把这条消息传播出去了。

用作名词 (n.)

Tv has become a more powerful vehicle for the spread of news.

电视已成为影响力更大的传播消息的媒介。

dispute

难度：4星核心词汇，属常用3000词

英汉解释

v.争论;辩驳;争议;质疑

n.争论;争端;争吵

参考例句

用作动词 (v.)

"I'm not disputing what you say, matt." said Tremaine, shaking his head.

“我并不是要跟你辩驳，麦特”，屈里曼说，摇摇头。

用作名词 (n.)

Everyone feared that the boundary dispute between these two countries would culminate in a war.

人人都担心，这两国间的边境争端将以一场战争告终。