title: Structures, properties, and energy-storage mechanisms of the semi-lunar process cuticles in locusts.
abstract: Locusts have excellent jumping and kicking abilities to survive in nature, which are achieved through the energy storage and release processes occurring in cuticles, especially in the semi-lunar processes (SLP) at the femorotibial joints. As yet, however, the strain energy-storage mechanisms of the SLP cuticles remain unclear. To decode this mystery, we investigated the microstructure, material composition, and mechanical properties of the SLP cuticle and its remarkable strain energy-storage mechanisms for jumping and kicking. It is found that the SLP cuticle of adult Locusta migratoria manilensis consists of five main parts that exhibit different microstructural features, material compositions, mechanical properties, and biological functions in storing strain energy. The mechanical properties of these five components are all transversely isotropic and strongly depend on their water contents. Finite element simulations indicate that the two parts of the core region of the SLP cuticle likely make significant contributions to its outstanding strain energy-storage ability. This work deepens our understanding of the locomotion behaviors and superior energy-storage mechanisms of insects such as locusts and is helpful for the design and fabrication of strain energy-storage devices.
authors.affiliation: Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.|State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wan
authors.affiliation: State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China.
authors.forename: Zhixiu
authors.initials: Z
authors.lastname: Hao
authors.affiliation: Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.|State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China.
authors.forename: Xiqiao
authors.initials: X
authors.lastname: Feng
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D004548:Elasticity; D005121:Extremities / Q000502:physiology; D020342:Finite Element Analysis; D019476:Insect Proteins / Q000502:physiology; D007814:Larva / Q000502:physiology; D008124:Locomotion / Q000502:physiology*; D048188:Locusta migratoria / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical
chemical_list: D019476:Insect Proteins; C047663:cuticle proteins, insects