For a long time, scientists have been trying to figure out exactly how butterflies fly. When compared with other flying creatures, butterflies are unique. The majority of flying animals look quite different from butterflies. Besides being physically beautiful, part of what makes butterflies so incredibly special is the fluttering and lilting flight, which is almost whimsical in appearance. Watching butterflies flit over a sunny meadow is fascinating and never fails to instill wonder in nearly everyone who sees them.
When compared with other animals that fly, such as bats and birds, a butterfly’s wings are broad, large, and unusually short in relative comparison to their body size. In theory, it doesn’t really make sense for them to be able to fly as efficiently as they do, but their flight has evoked countless poems, stories, and parables.
In fact, Per Henningsson, an associate professor in biology at a prominent Swedish university, told CNN that a butterfly’s wings are “quite inefficient,” and their ability to0 fly has been a mystery until now.
If you have ever found yourself wondering exactly what makes their flight seem so special, you’re in for a treat. Scientists from Lund University in Sweden decided to test a theory that’s 50 years old. The theory, which dates back to the 1970s, is that butterflies actually clap their wings together and create a jet by pushing out trapped air, thereby pushing the butterflies in the opposite direction.
As it turns out, the old theory is correct, and the biologists at Lund University have confirmed that butterflies do indeed clap their wings together. However, the way they clap their wings is even more sophisticated than the scientists initially believed. Because of how their wings are made, butterflies are uniquely evolved to give themselves better propulsion.
The butterflies studied by Lund University biologists were free-flying butterflies. The aerodynamic analysis revealed that the wings of a butterfly form a cupped shape in the butterfly’s upstroke. Then, they “clap” their wings, which serves the purpose of thrusting the butterfly forward. At the same time, the downstroke of the wings helps support the weight of the butterfly.
The wings aren’t simply two flat surfaces, Henningsson said. They were bending instead. Because of their flexibility, the wings formed a kind of pocket shape. The research team believes that by doing this, butterflies are able to capture more air between their wings. In essence, this boosts their performance by improving the clap.
To test their theory, the research group used a series of triangular-shaped robotic clappers. Some of the clappers were flexible, and others were rigid. They wanted to test out both types and found that the flexible wings were able to increase the clap’s efficiency by 28% in comparison to the rigid wings the biologists used. Additionally, the flexible clappers boosted the amount of produced force by 22%.
But it goes beyond mere efficiency. Butterflies have actually evolved for survival, the biologists believe. Their evolution seems to favor the unusual wing shape, and that helps them also to evade predators. That’s always a good thing. Nenningsson suggests that flexibility is likely one of the reasons for the wing’s unusual shape. Since butterflies can take off extremely quickly, it’s probably to keep themselves safe from predators. As Henninsson said in an interview with BBC News, being able to take off more quickly than other flying animals could mean the difference between life and death.
But what animals eat butterflies? You may be surprised at some of the seemingly benign creatures that seem to like adding beautiful butterflies to their daily menu options, including ants, wasps, birds, rats, snakes, lizards, monkeys, frogs, toads, and even spiders.
Butterflies aren’t the only animals that have developed the ability to use clapping propulsion. They’re in good company with some species of fish and frogs, according to France24.
The Royal Society published this study.