Abstract: The nocturnal scorpion Heterometrus petersii uses Basitarsal Compound Slit Sensilla (BCSS) as mechanoreceptor to detect me-chanical signal (e.g. substrate vibration, cyclic loads caused by walking) without fatigue failure such as initiation of fatigue crack and further propagation of crack-shaped slit. The outstanding perceptive function has been discovered for over half a century. However, it is not yet clear about the microstructure, material composition and micromechanical property which are all important factors that determine the fatigue fracture resistance of the BCSS. Here, the microscopic characteristics of the BCSS were thoroughly studied. The results in-dicate that anti-fatigue resilin and stiff chitinous cuticle form multilayered composite as the main body of the BCSS. Meanwhile, the pre-existing slit as mechanosensory structure is covered by cuticular membrane which has different mechanical property with the epicu-ticle. Theoretical analysis shows that the structure-composition-property synergistic relations of composites confer on the BCSS with extreme fatigue fracture tolerance.

Key words: slit-based mechanoreceptor, materials characterization;multilayered composite;resilin, fatigue fracture resistance