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.

蚊子的大腦是網狀的，以避免被捕殺，美國研究者周四說。動作按相反方向逃跑，以確保

就在出現(xiàn)危險苗頭時，這種昆蟲就會調整自己的起飛準備，確保徹底逃離，研究者們在發(fā)現(xiàn)中稱，這可以解釋為什么蚊子這么容易逃離人類敵人的拍打。

“這種運動非常之快，大約只用200毫秒，而在這么短的時間里，這種動物可以確定威脅的來源并刺激適當的一系列運動，以放置自己的腿和翅膀”，加州科技大學的Michael Dickinson 在一份發(fā)言中說。

“這說明了蚊子可以快速地處理敏感信息，作出適當的運動響應”，Dickinson說，其研究發(fā)表在《當代生物》期刊上。

Dickinson的研究團隊使用高速數字圖像設備和有趣的捕蚊拍研究了果蠅的處理反應過程。

對來自前方威脅的反應，蚊子向前移動其中間的腿，向后傾斜，并抬起后腿進行后向起飛。如果威脅來自側面，蚊子就在起飛前傾向另一側。

該研究發(fā)現(xiàn)對蚊子的神經系統(tǒng)有了新的看法，為怎樣智勝打敗蚊子提供了線索。

“最好不在蚊子的啟動位置去打它”，Dickinson說。而應該瞄準它的逃跑路線。

生物工程師Dickinson致力于昆蟲飛行的研究。它研制了一個微型機器人昆蟲叫Robofly和一個名為Fly-O-Vision的3D視覺飛行模擬器。