Dragonflies are one of the most ancient groups of insects, originating some 325 million years ago, and are known to be highly skilled flyers. Not only are they long-distance champions, but they perform a repertoire of complex flight manoeuvres.
Like cats always landing on their feet, dragonflies have a way of righting themselves when falling or being flipped upside down during flight. Executing moves like these requires the rapid processing of sensory information, while responding with precise body movements.
New research from Cornell University (US), published in Science, used both experimental and computational methods to analyse these flight manoeuvres. The experiments involved dragonflies being released from magnetic tethers from different orientations, then capturing the righting reflexes of the dragonflies on high-speed video at 4000 frames per second. Flight simulations were then modelled in three-dimensions based on these observations.
It turns out that dragonflies use wing pitch asymmetry, manipulating the angle between the horizon and each of their four individual wings, to recover to an upright position. With this technique, dragonflies can roll their bodies 180 degrees to recover from a fall in a tiny fraction of a second (0.2s).
The team, led by Zhen Jane Wang, also tested the insects’ visual system by blocking their three simple eyes (ocelli) and their two compound eyes. The team found that when vision was blocked the dragonflies were unable to perform the movements required to flip over and right themselves. This demonstrates that dragonflies strongly rely on these visual cues to calculate their position in space, and for the motor reflexes to respond accordingly in order to complete these aerial acrobatics.
This research not only helps us understand insect flying systems but could improve the engineering of robotic and mechanical flying technologies. Though we’re not quite at the stage of having Dune-esque ornithopters just yet…
Qamariya Nasrullah holds a PhD in evolutionary development from Monash University and an Honours degree in palaeontology from Flinders University.
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