How does a fly steer in flight?

Thanks to the work of English and Swiss researchers, it’s now possible to see exactly how the lightning-fast insect weaves its way through the air.

Using a new 3-D, X-ray scanning technique, researchers were able to offer a virtual glimpse at the inner workings of one of the more complex mechanisms in nature — the flight motor of a tiny blowfly.

‘The key question is how the fly’s tiny steering muscles, which make up less than 3 percent of its total flight muscle mass, influence the output of the much larger muscles that power its flight,” Graham Taylor, a professor at Oxford University’s Department of Zoology, said in announcing the findings, which appear in the most recent edition of the journal PLOS Biology .

Taylor said researchers discovered that the flies essentially turn much the way a car does. “The fly effectively ‘brakes’ on one side by diverting excess power into a steering muscle specialized to absorb mechanical energy,” he said.

Those complex movements happen quickly. In the time that it takes a human to blink, researchers said, a blowfly can beat its wings 50 times. Because its wings contain no muscles, each movement is controlled by tiny steering muscles — some as thin as a human hair — hidden out of sight within the thorax.

To record those concealed movements, researchers spun the flies around inside a Swiss laboratory. The insects reacted to being spun around by trying to turn and fly the opposite direction, allowing the researchers to capture X-ray images of their flight muscles in action from all angles. Those images were converted into 3-D visualizations, created a virtual video of the inner workings of flies in flight.

“For the first time, we can visualize how the power and steering muscles in the fly’s thorax work to enable stunningly aerobatic flight maneuvers unmatched by any man-made device,” Holger Krapp, a faculty member at the Imperial College London’s Department of Bioengineering, said in a statement. “Our study opens up the opportunity to uncover how the fly controls its sophisticated flight engine using the signals from different sensors and a brain no larger than the size of a pin head.”

Taylor said researchers hope the findings ultimately could be as practical as they are fascinating, “the development of new micro air vehicles and other micromechanical devices.”