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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.
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Scaling of Jumping Performance in Click Beetles (Coleoptera: Elateridae)
Synopsis Click beetles (Coleoptera: Elateridae) are known for their unique clicking mechanism that generates a powerful legless jump. From an inverted position, click beetles jump by rapidly accelerating their center of mass (COM) upwards. Prior studies on the click beetle jump have focused on relatively small species (body length ranging from 7 to 24 mm) and have assumed that the COM follows a ballistics trajectory during the airborne phase. In this study, we record the jump and the morphology of 38 specimens from diverse click beetle genera (body length varying from 7 to 37 mm) to investigate how body length and jumping performance scale across the mass range. The experimental results are used to test the ballistics motion assumption. We derive the first morphometric scaling laws for click beetles and provide evidence that the click beetle body scales isometrically with increasing body mass. Linear and nonlinear statistical models are developed to study the jumping kinematics. Modeling results show that mass is not a predictor of jump height, take-off angle, velocity at take-off, and maximum acceleration. The ballistics motion assumption is strongly supported. This work provides a modeling framework to reconstruct complete morphological data sets and predict the jumping performance of click beetles from various shapes and sizes.
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- PAR ID:
- 10420585
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Integrative And Comparative Biology
- Volume:
- 62
- Issue:
- 5
- ISSN:
- 1540-7063
- Page Range / eLocation ID:
- p. 1227-1234
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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