Analysis on surface nanostructures present in hindwing of dragon fly (Sympetrum vulgatum) using atomic force...

The present study involves the analysis of surface nanostructures and its variation present in the hind wing of dragon fly (Sympetrum vulgatum) using atomic force microscopy (AFM). The hindwing was dissected into 4 parts (D1-D4) and each dissected section was analyzed using AFM in tapping mode at different locations. The AFM analysis revealed the presence of irregular shaped nanostructures on the surface of the wing membrane with size varying between 83.25±1.79 nm to 195.08±10.25 nm. The size and shape of the nanostructure varied from tip (pterostigma) to the costa part. The membrane surface of the wing showed stacked arrangement leading to increase in size of the nanostructure. Such arrangement of the nanostructures has lead to the formation of nanometer sized valleys of different depth and length on the membrane surface giving them ripple wave morphology. The average roughness of the surface nanostructures varied from 18.58±3.12 nm to 24.25±8.33 nm. Surfaces of the wings had positive skewness in D1, D2 and D4 regions and negative skewness in D3 region. These surface nanostructures may contribute asymmetric resistance under mechanical loading during the flight by increasing the bending and torsional resistance of the wing.