Wings deployment in <i>Drosophila melanogaster</i>

During its final transformation to morph into its adult shape, an insect deploys its wings over just a couple of minutes. The wings rapidly unfold from a wrinkled compact structure to a plane which subsequently solidifies to generate rigidity. We study the wing expansion in Drosophila melanogaster. The expansion is regulated by an increase of the internal pressure and by the injection of a viscous liquid (hemolymph) into a network of deformable veins under hormonal control (Bursicon). We first characterize the kinematic of the deployment through macroscopic observation and quantify the fluid pressure, the fluid flow and the elastic properties of the wing structure during expansion. We then image sections of Drosophila wings using scanning electron microscopy to study the morphological evolution of the cross-section of the wings at different expansion stages. Combining scaling analysis and numerical simulations of the fluid-structure interaction between the viscous loading and the elastic deformation of the structure, we build a fundamental understanding of the dynamic of the wing expansion.