经济学人下载:昆虫的绝活 非常蟑螂

Science and technology
科学技术

Insect acrobatics
昆虫的绝活

Flipping roaches
非常蟑螂

How cockroaches vanish
蟑螂是怎么消失不见的？

ANYONE who has tried to swat a cockroach will know those insects' strange ability, in the heat of pursuit, to disappear.
只要打过蟑螂的都知道它们特殊的本领—往往在追赶最激烈的时候突然消失不见了。

Robert Full and his colleagues at the University of California, Berkeley, have now worked out how they do this—and taught a miniature robot to copy the feat.
加州大学伯克利分校的Robert Full和他的同事现在已明白它们是怎么做到的，并用一个微型机器人模拟了这个过程。

Dr Full had been using high-speed photography to study how cockroaches employ their antennae to sense and cross gaps.
Full博士运用了高速摄影技术来研究蟑螂是如何使触须去感知和穿过缝隙。

When the researchers made the gaps wider,
当研究者把缝隙扩宽，

they saw the animals flipping back underneath the ledge at the edge of the gap, rather than jumping across the empty space.
发现蟑螂直接在缝隙边缘翻转下去，而不是跳过缝隙，

As they report in the Public Library of Science, cockroaches running towards a gap suddenly grip the edge with the hooklike claws on their rear legs and swing 180°to land firmly underneath the ledge, upside down.
正如《科学公共图书馆》所报道的那样，蟑螂先迅速冲向缝隙，然后用后腿上的钩状爪子抓住边缘，顺势摆动180°，头朝下牢牢抓住平板底部。

They can pull off this stunt in a fifth of a second—so fast that the animals' bodies are subject to between three and five times the force of gravity,
它们能在0.2秒内完成这项绝技，这么快的速度蟑螂的身体要承受3到5倍的重力加速度，

and also so fast that the movement is invisible to the human eye.
也正是由于这么快的移动速度才让人类难以发现。

Dr Full and his colleagues have since identified similar behaviour in other animals with hooklike toes that are good at escaping pursuit:
Full博士和同事后来又发现了其他具有类似特性的生物，它们同样具有钩状的脚趾并擅长逃离追杀，

geckos, for example.
比如壁虎。

They have also teamed up with members of Berkeley's robotics laboratory to program a small six-legged robot that has strips of Velcro attached to its rear legs to do the same trick.
他们也与伯克利分校机器人实验室合作，设计了一只小型六脚机器人，然后把魔术贴粘在机器人的后腿上，最后成功完成了类似动作。

Such a robot could be fitted with a camera and used as a surveillance device.
这种机器人可以用来装配相机作为监视装置，

Some people, though, might prefer it to be fitted with a miniature machinegun and used as a UCPV.
尽管如此，一些人更希望它装配微型机枪变成自动蟑螂捕杀器。