来源:www.putclub.com 2019-03-28

Animal behaviour: A stilted story 
IF THERE were a Royal Society for the Prevention of Cruelty to Ants, Matthias Wittlinger of the University of Ulm, in Germany, would probably be top of its hate list. The reason is that Dr Wittlinger and his colleagues have, as they report in this weeks Science, been chopping the feet off ants. And not only that. They have been making other ants walk around on stilts.
Saharan desert ants of the genus Cataglyphis have to travel long distances to discover food in their impoverished, sandy environment. How they find their way home once they have done so is a mystery. Ants in more temperate climates often lay down chemical trails, but Cataglyphis, apparently, does not. Like honeybees and ancient mariners, they can navigate by the sun, so they know the general direction in which to travel. But, also like ancient mariners (who knew their latitude, but not their longitude), such solar reckoning cannot tell them when to stop.
Dr Wittlinger, therefore, decided to investigate a century-old hypothesis that desert ants have internal pedometersin other words, they count their steps out, and they count them back. When one total matches the other, they are home. To test this idea he trained his ants to walk from their nests to a feeding station through a ten-metre-long channel. When they had picked up the food, he caught them and made them return through a different channel, which also led to the nest. When they made this return journey, they began their characteristic nest-searching behaviour, quartering the ground in detail looking for the entrance, after travelling about ten metres.
Once the ants had mastered this trick, the experiment proper began. Some ants, when they arrived at the feeding station, had the ends of their legs amputated, to shorten their stride length. Others were fitted with stilts in the form of pig-bristles glued to their feet. Both lots were then returned to the feeding station, to make the journey home.
As predicted, the ants on stilts, whose stride-length meant their internal pedometers had not clicked enough times, walked blithely past their nests, and were left stranded almost five metres on the far side before they started looking for the hole. Meanwhile, the poor stumped ants travelled only about six metres before they started their search.
The story, however, has a happy ending. Having proved his point, Dr Wittlinger returned both stumped and stilted ants to the nest and gave them a few days to recover. Then he let them out for another run. Now that they could re-count their outbound journeys, they were able to calculate the journey home correctly.

Ants may not be very bright, but it seems they have a head for figures.



chop  v.砍,劈,斩;n.排骨,肉块

[真题例句] His colleague, Michael Beer, says that far too many companies have applied reengineering in a mechanistic fashion, chopping (v.) out costs without giving sufficient thought to long?term profitability.[1998年阅读2]
[例句精译] 他的同事迈克·比尔说,太多的企业用机械的方式进行机构重组,在没有充分考虑到长期效益的情况下就降低了成本。

impoverish  vt.使贫穷,使枯竭

[真题例句] To take advantage of this tool, some impoverished countries will have to get over their outdated anti?colonial prejudices with respect to foreign investment.[2001年阅读2]
[例句精译] 要想利用互联网,某些贫困国家必须克服对国外投资所持的过时了的反殖民的种种偏见。
apparent  a.①(to)明显的,显而易见的;②表面的,貌似的

[真题例句] It is generally recognized, (29:however), that the introduction of the computer in the early 20th century, (30:followed) by the invention of the integrated circuit during the 1960s, radically changed the process, (31:although) its impact on the media was not immediately (32:apparent) (①) .[2002年完形]

[例句精译] 但人们普遍都承认,20世纪早期电子计算机的出现,以及随后20世纪60年代发明的集成电路,虽然对传媒没有产生立竿见影的影响,但是却完全改变了发展进程。

reckon v.①认为,估计;②指望,想要;③测算

[真题例句] In science generally, however, the nineteenth century must be reckoned (①) as the crucial period for this change in the structure of science.


[例句精译] 然而,从科学这个整体来看,19世纪必须被视为科学结构发生变化的关键时期。

hypothesis  n.假说,假设,前提
[真题例句] Later, this idea became to be known as the Sapir-Whorf hypothesis, but this term is somewhat inappropriate.[2004年翻译]
[例句精译] 后来此观点成为著名的Sapir-Whorf假说,但这一说法并不适当。
stride  v.大步走(过),迈进,跨过;n.迈步,阔步
[真题例句] Every morning, its people (41:swarm) into the offices and factories of America, seeking a day?s work for a day?s pay, one day at a time.[1997年完形]
(41)[A] swarm[B] stride
[C] separate[D] slip
[例句精译] 每天早晨,公司的人们涌入美国的工厂和办公室,求得当日即付工资的工作,一次只干一天。
(41)[A] 云集,涌往[B] 大步走
[C] 分离的,分开的[D] 滑倒,滑掉