A group of Japanese researchers have created a fully functioning replica - or ornithopter - of a swallowtail butterfly to demonstrate its flight mechanism.
Using motion analysis software, the researchers were able to monitor the ornithopter's aerodynamic performance.
The swallowtail's wing area is particularly large compared to its body mass. This, combined with the overlapping forewings, means its flapping frequency is comparatively low and its general wing motion severely restricted.
As a result, its body motion is a passive reaction to the simple flapping motion, and not – as is common in other types of butterfly – an active reaction to aerodynamics.
The team demonstrated that flight can be realised with simple flapping motions without feedback control, a model which can be applied to future aerodynamic systems.
"The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion," say the authors.
"During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly."