Zoology. Scientists love to surprise. To seduce an ignorant audience, to arouse dreams among amateurs, to make speak about oneself among specialists even, nothing like the discovery of an unknown element, of an unexpected property, of a counter-intuitive rule. This chronicle of zoology itself regularly feeds on five-legged sheep, whitebirds and other delicious rarities.
Yet sometimes the beauty of science is showing the obvious. Take the butterflies of the genre Morpho. Perhaps the most iconic of the Lepidoptera. The iridescent blue color of some of the thirty listed species and their impressive size (up to 20 centimeters wingspan) seduced collectors from the 18th century.e century. But among scientists, another property has helped build the myth of morphos: their flight. They are the only butterflies, and even the only insects, accompanied to a lesser extent by dragonflies, to add gliding sessions to their flapping wings, as birds do. Longer or shorter periods depending on the species.
By comparing the butterflies of the Amazonian canopy and their cousins of the undergrowth, a French team has just shown that this ability to soar varies according to the environment but also according to the shape of the wings. “It is not exactly counter-intuitive, but it was still necessary to prove it and provide an explanation”, underlines Violaine Llaurens, evolutionary biologist and CNRS research director at the National Museum of Natural History. A first, concerning butterflies, which led to this research, “Made with the ends of a candle”, the honors of a publication in the journal Science, Thursday 25 November.
To carry out its demonstration, the team made up of Violaine Llaurens, her colleague Vincent Debat, professor at the National Museum of Natural History, and researcher Camille Le Roy went to Tarapoto, Peru, where the valleys Andines join the Amazon rainforest. No less than twelve species of morphos share the territory. For months, the researchers filmed them, first in their natural habitat, the bed of a river, then in a huge greenhouse, built for the occasion and equipped with three cameras. For each of these species, they analyzed the shape of the wings. Finally, with the help of Dutch researchers, they modeled the aerodynamic behavior of the different geometries and the associated performances.
You have 58.88% of this article to read. The rest is for subscribers only.