In the field of engineering, a crack, inducing enormous mechanical energy concentration at a tip, is considered a typical kind of defect. However, it is found that, to maximize the sensitivity of slit-based mechanoreceptors, the near-tip stress field of "risky" crack-shaped slits is ingeniously used by scorpions to precisely detect the cyclic loads acting on walking legs without the crack nucleation from the flaw-like tip. As a sophisticated biological mechanoelectrical transducing microsystem, the mechanoreceptor can effectively collect mechanical energy contained in the mechanical signal through antifracture slit allays and then convert the mechanical energy into electrical energy through mechanosensory neuron. The highly efficient mechanoelectrical energy conversion mechanism is theoretically analyzed and experimentally verified in a bioinspired artificial mechanoreceptor. The results demonstrate the potential of basic "design" principles, underlying the slit-dependent mechanoreceptor, for maximizing the electromechanical conversion efficiency of the industrial mechanoelectrical transducing microsystem such as nanogenerators, ultrasensitive mechanical sensors, self-powered portable, and wearable electronics.