A trio of researchers, two from Cornell University, the other from the Howard Hughes Medical Institute, have discovered the means by which dragonflies are able to right themselves so quickly from an upside-down orientation. In their 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, slender body, and multifaceted compound eyes. They are usually seen around ponds and marshes. They are also known for their agility in flight, and it is this characteristic that has led researchers to question their ability to recover from a scenario they are unlikely to encounter naturally – falling suddenly. Upside down.
The job was to collect specimens for laboratory study. They started by grabbing specimens, turning them over and dropping them. They found that all of the specimens recovered very quickly – so quickly that the researchers were unable to follow the action. Then they painted small white dots on the wings and bodies of several specimens and filmed them falling using a high-speed camera. In the slow-motion video, they could only partially determine what the dragonflies were doing to turn around.
Unfazed, the researchers used the video to create a computerized 3D model of the dragonflies as they reared up. Then they could see exactly what the dragonflies were doing when they fell – they flung their left and right wings at slightly different angles, forcing their bodies to rotate until they were upright again. They noted that some rolled to the left, while others rolled to the 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 then turned them around and let them go – none of the dragonflies were able to recover , suggesting that they use visual cues to orient themselves.
Dragonflies perform upside-down backflips to straighten up
Z. Jane Wang et al, Recovery mechanisms in the dragonfly righting reflex, Science (2022). DOI: 10.1126/science.abg0946
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Quote: How Dragonflies Right Up When Dropped Upside Down (May 13, 2022) Retrieved May 14, 2022 from https://phys.org/news/2022-05-dragonflies-upside.html
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