Insect wing flexibility with an emphasis on flies

When flying, many insects perform complex flight behaviours using their wings. Insect wings are flexible body appendages and can bend and twist in flight. Their properties vary across different species, but overall there seem to be possible benefits of deformable over rigid wings. For certain configurations, flexible wings have been shown to be aerodynamically favourable, although in other experiments the opposite was found to be true.
In order to further investigate the areodynamic effects of flexibility, we plan to create a flexible fly wing model to be used in computational fluid dynamics simulations. As a biological basis for this model, we have conducted static stiffness measurements of fly wings by locally applying small point forces on wings fixed at the wing base. In this talk, I will present these experiments and their results. We found spring stiffnesses between ca. 0.02 to 1.0 N/m in fruit flies and  ca. 0.2 and 2.8 N/m in blowflies. While the line between point of force application and wing base can be approximated as a cantilever beam for the small deformations induced in these experiments, the wing also shows deformation along other directions.