Launching engineered prototypes to better understand the factors that influence click beetle jump capacity*

In nature, click-beetles use a unique hinge structure between their prothorax and mesothorax that acts as a latch-mediated spring actuation system to produce a high acceleration that can result in a jump. This mechanism enables them to jump a height of several times their body length without using their legs when the beetle is unconstrained. To study the beetle jump trajectory, we designed simplified beetle-inspired prototypes and a launching platform. The simplified prototypes are fundamentally two masses connected by a spring. The masses simulate the portion of a click beetle’s body located anteriorly (M1) and posteriorly (M2) to the clicking mechanism, and the spring simulates the elastic energy storage element. The launcher uses a quick-reaction release mechanism and magnetic actuator to simulate the unlatching process. In trajectory analysis, the parameters that are most important are initial velocity at take-off and the take-off angle since both the click beetles and the prototypes are governed by ballistic motion. We determined that morphological features such as elytra (body) curvature and the ratio of the two body masses affect these two dynamic parameters. Our findings provide further insight into the design and fabrication of legless jumping robotic mechanisms and apply engineering models and experimental tools to answer key biological questions.