Measurements on mechanical parameters and studies on microstructure of elytra in beetles

The mechanical parameters and microstructures of the elytra were studied for four kinds of beetles (Potosia (Liocola) brevitarsis lewis, Cybister, Allomyrina dichotoma, Holotrichia trichophora). The elytras microstructures in cross-sections show that the elytra are composed of the compact dorse, the hollow section and the ventral face, the chitin fibre hollow-pillar structure connects the compact dorse and the ventral face, and the elytra couple each other with the concave-convex structure. The Youngs modulus and hardness of the elytra measured by the Nano Indenter SA2 (MTS) are 9.08, 8.21, 4.76, 6.00 GPa and 0.44, 0.48, 0.18, 0.18 GPa, respectively. Coupling forces between the elytra measured by a Multifunctional Test Machine are 46.43, 7.38, 11.34 mN/mm for Potosia (Liocola) brevitarsis lewis, Cybister and Allomyrina dichotoma. The research provides biomimetic information for light structure designs.