High-speed X-ray analysis reveals how click beetles can perform ultra-fast movements and avoid significant damage from the massive accelerations generated during the clicking maneuver. When click beetles bend their bodies along a thoracic hinge, quick release of the hinge rotates the head forward in a spring-like fashion, an extreme motion too powerful to be generated by muscles alone. Ophelia Bolmin and colleagues investigated the physical mechanisms that enable click beetles to generate these extreme movements. The authors captured the bending motion of four beetles with high-speed synchrotron X-ray imaging that allowed visualization of internal structures. Analysis revealed three distinct phases and that energy is released much faster than it is stored, supporting the idea that click beetles can amplify mechanical power. The images revealed large displacements of the soft cuticle near the hinge during loading and energy release, indicating that it is likely part of the distributed spring mechanism. The authors then used non-linear system identification to characterize forces associated with the hinge's release. Oscillations at the hinge are governed by snap-through buckling, an instability also used by Venus flytraps to close around prey. According to the authors, understanding the dynamics of extreme maneuvers could inform development of insect-inspired robots.
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Article #20-14569: "Nonlinear elasticity and damping govern ultrafast dynamics in click beetles," by Ophelia Bolmin et al.
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Proceedings of the National Academy of Sciences