title: Unconventional lift-generating mechanisms in free-flying butterflies.
abstract: Flying insects generate forces that are too large to be accounted for by conventional steady-state aerodynamics. To investigate these mechanisms of force generation, we trained red admiral butterflies, Vanessa atalanta, to fly freely to and from artificial flowers in a wind tunnel, and used high-resolution, smoke-wire flow visualizations to obtain qualitative, high-speed digital images of the air flow around their wings. The images show that free-flying butterflies use a variety of unconventional aerodynamic mechanisms to generate force: wake capture, two different types of leading-edge vortex, active and inactive upstrokes, in addition to the use of rotational mechanisms and the Weis-Fogh 'clap-and-fling' mechanism. Free-flying butterflies often used different aerodynamic mechanisms in successive strokes. There seems to be no one 'key' to insect flight, instead insects rely on a wide array of aerodynamic mechanisms to take off, manoeuvre, maintain steady flight, and for landing.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: R B
authors.initials: RB
authors.lastname: Srygley
authors.forename: A L R
authors.initials: AL
authors.lastname: Thomas
mesh_terms: D000392:Air Movements; D000818:Animals; D002080:Butterflies / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology*; D035264:Flowers; D012906:Smoke; D014921:Wings, Animal / Q000502:physiology*
chemical_list: D012906:Smoke