Now experts have found that the insects “clap” their wings together – and the wings are perfectly designed for better propulsion.
Biologists from Sweden’s Lund University sat down to test a 50-year-old theory that butterflies “clap” their wings together, push out the trapped air to create a jet and push the animal in the opposite direction.
“Butterflies look different from many other flying animals, compared to birds and bats. They have a very extreme wing shape – very large, short, but very wide wings compared to their small body,” Per Henningsson, associate professor of biology at Lund University, told CNN. “It̵
The biologists studied free-flying butterflies, and in their aerodynamic analysis, the creatures’ wings found a cupped shape during stroking and “clapping”, and threw the butterfly forward. In the meantime, the impact helps with weight support.
They also noticed that the butterfly wings behaved in an unusual way – instead of collapsing, like two flat surfaces, the wings bent to create a “pocket shape”, which would capture more air and improve propulsion.
“When the wings go up during the upwelling, and they collapse at the end of the spread, we saw that they were not just two flat surfaces,” Henningsson explained.
“Instead, they bent, and because of their flexibility, they formed a kind of pocket shape,” he said, adding that the team believed that butterflies captured more air between their wings by doing so, which improved the flap and increased performance. .
The team tested their theory using a series of triangular robotic flaps, and found that flexible wings increased flap efficiency by 28% compared to rigid wings
Experts believe the creatures may have evolved to favor this unusual wing shape to avoid predators.
“This flexibility may be one of the reasons why they have this unusual wing shape,” said Henningsson. “Butterflies take off very quickly – they do this as a safety precaution to minimize the risk of being caught,” he explained.
The research was published on Wednesday in the journal Interface.