To validate this hypothesis, and to elucidate the dynamic and functional role of microtubules in cell mechanics, we investigated their properties during wing development. Live cell imaging of EOS-?-tubulin (EOS-Tub) showed that microtubules were not static but engaged in complex and dynamic rearrangements. An analysis of microtubule straightness showed that in wing cells, virtually all microtubules along the P–D axis were bent (Fig. 2a–d; Supplementary Movie 5), consistently undergoing short wavelength buckling (~3 ?m) near the cell cortex (Fig. 2b,e; Supplementary Fig. 1b). We further observed that growing microtubules remain straight and only start to buckle after they reach the cell cortex (Fig. 2g; Supplementary Movie 6), exhibiting local short wavelength buckling near these sites. This result indicates that microtubule polymerization can generate considerable compressive forces to induce microtubule buckling.