Dragonflies perform upside down backflips to stand up

The results add to current knowledge of how insects fly and stabilize in the air. They could also help inspire new designs of small aerial vehicles like drones, which can be useful for search and rescue attempts and building inspections.

Our colorful companions for sunny days can hover, fly backwards and travel up to 54 km / h when hunting for prey or evading predators – but like any flying creature, they can be out of balance and even end up in flight. ‘towards.

Many land animals like cats and aerial animals like hoverflies spin around an axis head to tail when they fall, which is called ‘rolling’, but not much is known. on how most insects turn away from extreme directions.

In a new study published today in Proceedings of the Royal Society BResearchers at Imperial College London have found that unlike many animals documented to date, dragonflies most often perform upside down backflips, called “ pitching, ” to straighten up from positions to the upside down in the air.

They also found that dragonflies perform the same righting maneuver when unconscious, suggesting that the response has a large component of passive stability – a flight mechanism like the one that allows planes to glide when their engines are turned off. . Research reveals how the shape and joint stiffness of dragonfly wings provide passive stability and could inform the design of small drones.

Lead author Dr Huai-Ti Lin, Imperial’s Department of Bioengineering, said, “Engineers could learn from flying animals to improve aerial systems. help engineers integrate passive stability mechanisms into their wing structure. “

To conduct the study, the researchers dressed 20 common darter dragonflies with tiny magnets and motion-tracking dots like those used to create CGI images.

They then magnetically attached each dragonfly to a magnetic platform either to the right or upside down with some variations in tilt, before releasing the plummeting insects. The motion tracking points provided moving 3D models of the dragonfly’s movements, which were captured by high-speed cameras for 3D reconstruction.

They discovered that the conscious dragonflies, when they fell from the upside down position, somersaulted backwards to regain the upright position. The dragonflies that were unconscious also completed the somersault, but more slowly.

The dead dragonflies did not perform the maneuver at all, but when their wings were raised in specific alive or unconscious positions by the researchers, they were able to complete the righting maneuver – albeit with a bit more spinning around. vertical axis than in living dragonflies. Researchers say this suggests that the maneuver relies on both muscle tone and wing posture, which is built into the dragonfly as a passive response rather than active control.

Lead author Dr Sam Fabian, also from the Department of Bioengineering, said: “Airplanes are often designed so that if their engines fail, they glide steadily rather than fall from the sky. We have seen a similar response in dragonflies, despite the lack of an active beat, meaning that some insects, despite their small size, can take advantage of passive stability without active control.

“Passive stability reduces the effort requirements of flight, and this characteristic likely influenced how dragonfly shapes evolved. Dragonflies that use passive stability in flight are likely to have an advantage, as they use less energy and are better able to recover from bothersome events. “

Researchers are continuing their research into the biomechanics of dragonfly flight and will then study how these passive effects affect a dragonfly’s active vision and guiding strategies in intercepting prey and avoiding obstacles.