Meeting Abstract
65-4 Saturday, Jan. 5 14:15 – 14:30 The click beetle latch mechanism: An in-vivo study using synchrotron x-rays BOLMIN, O*; SOCHA, JJ; ALLEYNE, M; DUNN, AC; WISSA, AA; University of Illinois at Urbana-Champaign ; Virginia Tech ; University of Illinois at Urbana-Champaign ; University of Illinois at Urbana-Champaign ; University of Illinois at Urbana-Champaign awissa@illinois.edu http://bamlab.mechse.illinois.edu/
Click beetles (Coleoptera: Elateridae) have evolved a unique mechanism of jumping without the use of legs. The ‘click’ mechanism that produces the jump is a power-amplified system that includes a thoracic hinge, stored energy, and very fast energy release. The hinge is composed of a peg and a mesosternal lip, two conformal parts that allow the body to be locked in a characteristic arched position before the jump. In this presentation, we answer the following questions: What are the kinematics of the latching phase, the cuticular deformation and the hinge’s geometry prior to the fast energy release? Thus, we imaged live click beetles (Melanotus spp., Parallelosthetus attenuatus and Conodus lividus) using synchrotron x-rays at Argonne National Laboratory’s Advanced Photon Source. The beetles were constrained at the abdomen, allowing only the head and prothorax to rotate around the hinge. Clicks (i.e. energy release) were induced in response to the restraint and by reaction to the x-ray radiation. High-speed recordings of the hinge show, for the first time, high resolution of the latch mechanism of the peg on the mesosternal lip and the contraction of soft cuticle prior to energy release. All videos were post-processed using ProAnalyst, ImageJ, and Matlab to quantify the cuticular deformations and latching kinematics. The path of the peg along the mesosternal lip during the latching phase was measured for all species. The click maneuver is characterized by the geometric angle after which the energy release begins. Power amplification magnitude was quantified by comparing the timing of latching and release phases.
