Scientists have long wondered at how the butterfly moves in the same way the wind moves.
It has long been believed that butterflies pressed their large wings ‘vigorously’, but scientists in Sweden have now determined that motion is more complex than previously understood.
Instead of just beating them, they flex their colored feathers to create a ‘pocket’ that traps more air and provides more propulsion.
The extra boost in speed of liftoff can help the royal lepidopteran avoid predators.
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Scientists in Sweden analyzed a slow-motion video of silver-washed fritillary in flight and determined that the butterfly did not flap its wings. This creates a ‘pocket’ when they come together, aiding in propulsion
Butterflies are delicious food for a wide variety of animals, including frogs, spiders, lizards and birds.
“If you’re a butterfly who is able to take off quicker than others, it gives you a clear advantage,” Per Hennesson, a biologist at Lund University, told the BBC.
He said, “This is a strong selective pressure, because it is a matter of life and death.”
In an analysis published in the journal Interface, Henningson and fellow biologist Christopher Johansson showed that a butterfly’s ‘clap’ creates a jet of aerial propulsion.
Researchers believe that the added emphasis at takeoff may help butterflies avoid predators such as frogs and birds
He also found that this move has been performed ‘in a far more advanced way than we have realized,’ Henningsingen told AFP.
At the time the wings collided together, they were ‘not just two flat surfaces colliding together.’
Instead, they create a ‘pocket’ shape that entraps more air.
Henningsen said it was unclear whether the butterflies use pocket technology during free flight, but in the take-off phase, they certainly do it a lot. ‘
After watching a slow-motion video of the common silver-wash fritillary in flight, Henningsen and Johansson fashioned two pair of simple mechanical wings.
One set was rigid, the other as flexible as real butterfly wings.
Mechanical wings that were flexible like a butterfly were 28 percent more efficient and 22 percent better than hard power
Researchers found that flexible wings were 28 percent more energy efficient – a ‘dramatic improvement’ – and 22 percent better at generating force.
“Traditionally considered aerodynamically inefficient,” butterfly wings may be ideally suited to pocket size, Henningson said.
He said his findings could be helpful in building drones that use clapping propulsion.
Last year, the Cosmos unveiled a bird-shaped ‘ornithopter’ to engineers at the University of South Australia, ‘a flying machine that flaps its wings to produce further wings.
‘People who are working on these designs … they should notice the behavior of this cup-shape, because they are there [is] Henningsson told the BBC that it would achieve a lot of efficiency and effectiveness.
The report can also help underline the importance of research into these beautiful bugs, whose numbers are in serious decline.
A new report from Butterfly’s Conservation Europe found that the butterfly population in Britain has halved in 1976, with nearly one in ten British butterfly species becoming extinct due to habitat destruction.
In California, the number of western monarchy butterflies has declined sharply in recent years, from tens of thousands and millions to fewer than 2,000 butterflies.
Sarina Jepsen of the Xeras Society, which conducts an annual census of California kings, told the AP that ‘her absence this year was heartbreaking.’