The brains of flies are wired to avoid the swatter, US researchers said on Thursday.

At the mere hint of a threat, the insects adjust their preflight stance to flee in the opposite direction, ensuring a clean getaway, they said in a finding that helps explain why flies so easily evade swipes from their human foes.

"These movements are made very rapidly, within about 200 milliseconds, but within that time the animal determines where the threat is coming from and activates an appropriate set of movements to position its legs and wings," Michael Dickinson of the California Institute of Technology said in a statement.

"This illustrates how rapidly the fly's brain can process sensory information into an appropriate motor response," said Dickinson, whose research appears in the journal Current Biology.

Dickinson's team studied this process in fruit flies using high-speed digital imaging equipment and a fancy fly swatter.

In response to a threat from the front, the fly moves its middle legs forward, leans back and raises its back legs for a backward takeoff. If the threat is from the side, the fly leans the other way before takeoff.

The findings offer new insight into the fly nervous system, and lends a few clues on how to outsmart a fly.

"It is best not to swat at the fly's starting position," Dickinson said. Instead, aim for the escape route.

Dickinson, a bioengineer, has devoted his life's work to the study of insect flight. He has built a tiny robotic fly called Robofly and a 3-D visual flight simulator called Fly-O-Vision.

蚊子的大脑是网状的，以避免被捕杀，美国研究者周四说。动作按相反方向逃跑，以确保

就在出现危险苗头时，这种昆虫就会调整自己的起飞准备，确保彻底逃离，研究者们在发现中称，这可以解释为什么蚊子这么容易逃离人类敌人的拍打。

“这种运动非常之快，大约只用200毫秒，而在这么短的时间里，这种动物可以确定威胁的来源并刺激适当的一系列运动，以放置自己的腿和翅膀”，加州科技大学的Michael Dickinson 在一份发言中说。

“这说明了蚊子可以快速地处理敏感信息，作出适当的运动响应”，Dickinson说，其研究发表在《当代生物》期刊上。

Dickinson的研究团队使用高速数字图像设备和有趣的捕蚊拍研究了果蝇的处理反应过程。

对来自前方威胁的反应，蚊子向前移动其中间的腿，向后倾斜，并抬起后腿进行后向起飞。如果威胁来自侧面，蚊子就在起飞前倾向另一侧。

该研究发现对蚊子的神经系统有了新的看法，为怎样智胜打败蚊子提供了线索。

“最好不在蚊子的启动位置去打它”，Dickinson说。而应该瞄准它的逃跑路线。

生物工程师Dickinson致力于昆虫飞行的研究。它研制了一个微型机器人昆虫叫Robofly和一个名为Fly-O-Vision的3D视觉飞行模拟器。