How dragonflies straighten up when dropped upside down

How dragonflies straighten up when dropped upside down

How dragonflies straighten up when dropped upside down

Dragonfly recovers from a fall on its head with complex wing movement in ~200ms. Photo credit: Z Jane Wang, Cornell University

A trio of researchers, two from Cornell University, the other from the Howard Hughes Medical Institute, have discovered the means by which dragonflies can right themselves so quickly from an upside-down orientation. In her article published in the journal ScienceZ. Jane Wang, James Melfi, and Anthony Leonardo describe experiments they conducted with flying dragonflies and what they learned about the insect’s flight mechanics.

Dragonflies are flying insects characterized by pairs of transparent wings, a long, thin body, and multifaceted compound eyes. They are generally seen around ponds and swamps. They’re also known for their flight agility, and it was this trait that led researchers to wonder about their ability to recover from a scenario they’re unlikely to find themselves in naturally – suddenly upside down to fall.

The work involved collecting samples for laboratory testing. They started by grabbing samples, turning them over and dropping them. They found that all of the samples recovered very quickly — so quickly that the researchers were unable to follow the action. Next, they drew small white dots on the wings and bodies of several specimens and filmed them falling with a high-speed camera. In the slow-motion video, they could only partially see what the dragonflies were doing to turn on the right side.







Dragonfly recovers from a fall on the head in ~200ms. The calculation of the righting maneuver reveals the key control strategy that leads to the roll maneuver. Photo credit: Z Jane Wang, Cornell University

Undaunted, the researchers used the video to create a 3D computerized model of the dragonflies as they perched. Then they could see exactly what the dragonflies were doing as they fell – flapping their left and right wings at slightly different angles and forcing their bodies to rotate until they were right side up again. They found that some rolled left while others rolled right, but in both cases the end result was the same – a resumption of normal flight.

The researchers then wondered how the insects knew they were upside down – to find a possible answer, they covered the eyes of several specimens, turned them over and dropped them – none of the dragonflies were able to recover, suggesting this that they use visual cues for orientation.

How dragonflies straighten up when dropped upside down

Dragonfly recovers from a fall on the head in ~200ms. The calculation of the righting maneuver reveals the key control strategy leading to the roll maneuver. Photo credit: Z Jane Wang, Cornell University


Dragonflies perform reverse back flips to right themselves


More information:
Z. Jane Wang et al, Recovery Mechanisms in the Dragonfly Righting Reflex, Science (2022). DOI: 10.1126/science.abg0946

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Citation: How dragonflies right themselves when they fall upside down (2022 May 13) Retrieved May 14, 2022 from https://phys.org/news/2022-05-dragonflies-upside.html

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