Now, experts have discovered that insects “clap” their wings – and their wings are perfectly evolved for better propulsion.
Biologists at Lund University in Sweden have set out to test a 50-year-old theory that butterflies “clap” their wings together, pushing trapped air to create a jet and pushing 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 bodies,” said Per Henningsson, an associate professor of biology at Lund University told CNN. “This is a bit of a puzzle, because this type of wing is pretty inefficient.”
Biologists studied free-flying butterflies and, in their aerodynamic analysis, found that the creatures’ wings formed a cup-shaped shape during the ascending race and “clapped”, pushing the butterflies forward. Meanwhile, the downward stroke helps support the weight.
They also noticed that butterfly wings behaved in an unusual way – instead of slamming together, like two flat surfaces, the wings bent to create a “pocket shape” that would catch more air and improve propulsion.
“When the wings rose during the ascent and clapped at the end of the ascent, I saw that there were not just two flat surfaces,” Henningsson explained.
“Instead, they bent over and, because of their flexibility, formed a kind of pocket shape,” he said, adding that the team believed that in doing so, the butterflies caught more air between the wings, which improved. palm and increased performance.
The team tested their theory using a series of triangular robotic flaps and found that the flexible wings increased palm efficiency by 28% compared to rigid wings
Experts believe that the creatures could have evolved to favor this unusual shape of the wing to evade predators.
“This flexibility could be one of the reasons they have this unusual wing shape,” Henningsson said. “Butterflies take off very quickly – they do this as a safety measure, to minimize the risk of being caught,” he explained.
The research was published Wednesday in the journal Interface.