Dragonflies do flip flops upside down to correct themselves

Dragonflies do flip flops upside down to correct themselves

Credit: Imperial College London / Caroline Brogan

The findings contribute to the current knowledge of how insects fly and remain stable in the air. They can also help inspire new designs in small aircraft such as drones, which can be useful for search-and-rescue efforts and building inspections.

Our colorful companions can glide, fly backwards and move up to 54 km / h on a sunny day when hunting prey or escaping from predators – but like any flying creature, they can be thrown off balance and even upside down.

Many land animals, such as cats, and aerial animals such as gliders, rotate around a head-to-tail axis when they fall, known as ‘roll’, but not much is known about how most insects themselves of extremes do not correct orientations.

In a new study published today in Proceedings of the Royal Society B, Researchers from Imperial College London have found that, unlike many animals documented so far, dragonflies mostly perform upside-down backflies, known as ‘pitching’, to correct themselves from upside-down positions in the air.

They also found that dragonflies maneuver the same right hand while unconscious, suggesting that the reaction has a large component of passive stability – a flight mechanism like those that cause aircraft to slip when their engines are turned off. The research reveals how the shape and stiffness of the dragonflies’ wings provide passive stability and the designs for small drones can help.







Credit: Imperial College London / Caroline Brogan

Senior author dr. Huai-Ti Lin, of Imperial’s Bioengineering Department, said: “Engineers can draw inspiration from flying animals to improve air systems. Drones mostly rely on rapid feedback to keep them up and on course, but our findings can help engineers to incorporate passive stability mechanisms into their wing structure. ‘

To conduct the study, the researchers dressed 20 common dragonfly butterflies with small magnets and motion detection dots such as those used to create CGI images.

Thereafter, they magnetically attached each dragonfly to a magnetic platform, either to the right or upside down, with a degree of oblique alternation, before releasing the insects into a free fall. The motion detection points provided moving 3D models of the dragonfly motions, captured by high-speed cameras for 3-D reconstruction.

They found that conscious dragonflies, while falling from the upside-down position, jerked backwards to regain the right-top position. Dragonflies that were unconscious also completed the somersault, but more slowly.







Credit: Imperial College London / Caroline Brogan

Dead dragonflies did not perform the maneuver at all, but when their wings were placed in specific live or unconscious positions by researchers, they were able to complete the corrective maneuver – albeit with a little more rotation around the vertical axis than in live dragonflies. The researchers say this suggests that the maneuver depends on both muscle tone and wing posture, which are built into the dragonfly as a passive response rather than an active control.

Chief author, dr. Sam Fabian, also from the Department of Bioengineering, said: “Aircraft are often designed so that if their engines break down, they will slip stably rather than fall from the sky. We see a similar reaction in dragonflies, despite the lack of active clapping, which means that some insects, despite their small size, can utilize passive stability without active control.

“Passive stability reduces the effort requirements of flight, and this property probably influenced how dragonfly shapes evolved. Dragonflies that use passive stability during flight are likely to have an advantage because they consume less energy and are better able to recover from inconvenient events. . “

The researchers will continue to investigate dragonfly fly biomechanics and will then investigate how these passive effects affect a dragonfly’s active vision and guidance strategies in intercepting prey and avoiding obstacles.


The secret of dragonflies’ flight


More information:
DragonDrop: a new passive mechanism for correcting the air in the dragonfly, Proceedings of the Royal Society B, rspb.royalsocietypublishing.or… .1098 / rspb.2020.2676

Provided by Imperial College London

Quotation: Dragonflies perform upside-down backflies to correct themselves (2021, February 9) Retrieved February 10, 2021 from https://phys.org/news/2021-02-dragonflies-upside-backflips.html

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