Japanese researchers have built an artificial butterfly that mimics the unusual flight patterns of the swallowtail butterfly. Their tiny model is called an "ornithopter" - and we've got the video of the little guy in flight.
What makes the swallowtail unusual relative to other butterflies is its very large wings, which dwarf its comparatively tiny body. As such, they flap their wings far less often than other kinds of butterflies and lack the more precise control that comes with smaller wings. This means that flight is a much more passive process for the swallowtail butterfly, and that it is not responding to aerodynamic forces in the same way that other butterflies do.
The purpose of the ornithopter was to show that the swallowtails could indeed achieve forward flight by simply flapping their wings, without any reliance on aerodynamic feedback. To do this, the research team built a lifelike replica of the butterfly, right down to the tiny membranes and veins found on its wings. The video below shows the results of their efforts, as the ornithopter does indeed (briefly) achieve forward flight. The thought is that this breakthrough could lead to flapping wings being used in future flying machines due to the greatly reduced need for feedback during flight.