Dragonflies perform ‘upside down backflips’ to right themselves — even while unconscious, research reveals

Insects’ innate orientation mechanisms could inspire aircraft design improvements, writes Harry Cockburn

A common darter dragonfly. Why roll when you can somersault? (Getty)

What happens if a dragonfly gets blown upside down while in flight? Well, instead of barrelling over so it is the right way up again, they instead take the opportunity to perform “upside down backflips” to regain their balance and reorient themselves, according to new research.

Dragonflies are already recognised as being capable of complex aerial manoeuvres, and are able to glide, fly backwards and travel up to 54kph (34mph). 

But while many land-based animals such as cats, and flying insects such as hoverflies, rotate themselves around a head-tail axis when righting themselves when falling, little is known about how most insects regain their orientations.

The new study reveals that dragonflies are unusual in their ability to perform these upside down backflips – known as pitching – and the findings add to current knowledge of how insects fly and remain stable in the air.  

The research team, from Imperial College London, also found dragonflies perform the same righting manoeuvre whilst unconscious, suggesting the response has a large component of passive stability – a flight mechanism like that which lets planes glide when their engines are switched off. 

The research reveals how the shape and joint stiffness of the dragonflies' wings provide passive stability and could inform designs for small drones.

The scientists have suggested their study could also help to inspire new designs in small aerial vehicles like drones.

Senior author Dr Huai-Ti Lin, of Imperial's Department of Bioengineering, said: “Engineers could take inspiration from flying animals to improve aerial systems. 

“Drones tend to rely heavily on fast feedback to keep them upright and on course, but our findings could help engineers incorporate 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 imagery.

They then magnetically attached each dragonfly to a magnetic platform either the right way up or upside-down with some variations in tilt, before releasing the insects into a freefall. 

The motion tracking dots provided moving 3D models of the dragonfly movements, which were captured by high-speed cameras for 3D reconstruction.

They found the conscious dragonflies, when dropped from the upside-down position, somersaulted backwards to regain the rightside-up position. 

Dragonflies that were unconscious also completed the somersault, but more slowly.

Dead dragonflies did not perform the manoeuvre at all, but when their wings were posed into specific live or unconscious positions by researchers, they were able to complete the righting manoeuvre – albeit with a little more spin around the vertical axis than in live dragonflies. 

The researchers said this suggests the manoeuvre relies on both muscle tone and wing posture, which is inbuilt in the dragonfly as a passive response rather than an active control.

Lead author Dr Sam Fabian, also of the Department of Bioengineering, said: “Planes are often designed so that if their engines fail, they will glide along stably rather than drop out of the sky.

“We saw a similar response in dragonflies, despite the lack of active flapping, meaning that some insects, despite their small size, can leverage passive stability without active control.

“Passive stability lowers the effort requirements of flight, and this trait likely influenced how dragonfly shapes evolved.” 

He added: “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 inconvenient events.”

The research team is now planning to investigate how these passive effects impact a dragonfly’s active vision and guidance strategies in prey interception and obstacle avoidance.

The research is published in the Proceedings of the Royal Society B.