The fluttery flight of butterflies is unique. It is also optimal.
The upstroke of butterfly wings employs a novel clap technique. During the upward stroke, the wings cup, creating an air-filled pocket between them. When the wings then collide, the air is forced out, resulting in a backward jet that propels butterflies forward. The downward stroke keeps butterflies aloft.
“That the wings are cupped when butterflies clap them together makes the wing stroke much more effective. It is an elegant mechanism. Butterflies benefit from the technique when they have to take off quickly to escape from predators,” says Swedish zoologist Per Henningsson.
The flexibility of butterfly wings abets their performance. For the flight type, flexible wings are 28% more efficient than rigid wings would be.
L.C. Johansson & P. Henningsson, “Butterflies fly using efficient propulsive clap mechanism owing to flexible wings,” Interface (20 January 2021).
“Butterfly wing clap explains mystery of flight,” ScienceDaily (21 January 2021).