Scientists Study Incredible Energy of Click Beetles' Jump Motion
Click beetles have the capacity to propel themselves more than 20 times their own height into the air without using their legs.
A group of researchers from the University of Illinois Urbana released a paper on the physical mechanisms that allow the beetles' signature clicking maneuver in a study that has potential applications for machines built using the principles of biomimicry.
Studying the immense jumping power of click beetles
The new study examines the forces behind the super-fast energy release that allows click beetles to jump to such great heights. In doing so, it also provides guidelines for studying extreme motion, energy storage, and energy release in small insects and animals.
Incredibly, click beetles use a unique hingelike tool in their thorax, just behind the head, to jump into the air.
To determine how this mechanism works the team used high-speed X-rays. These allowed them to observe and quantify how the click beetle's external and internal anatomy — including muscle, other soft structures, and the insect's rigid exoskeleton — moves throughout the jumping process.
"The hinge mechanism has a peg on one side that stays latched onto a lip on the other side of the hinge," entomology professor Marianne Alleyne, who was part of the research team, explained in a press release.
"When the latch is released, there is an audible clicking sound and a quick unbending motion that causes the beetle’s jump," she continued.
Faster than Earth's gravitational acceleration
The researchers observed large, yet relatively slow deformations in the soft tissue parts of the beetles' hinge in the lead-up to the jumping motion.
"When the peg in the hinge slips over the lip, the deformation in the soft tissue is released extremely quickly, and the peg oscillates back and forth in the cavity below the lip before coming to a stop," mechanical science and engineering professor Aimy Wissa, who was also part of the study, explained.
"The fast deformation release and repeated, yet decreasing, oscillations showcase two basic engineering principles called elastic recoil and damping," she continued.
As the researchers point out, the acceleration of this motion is a staggering 300 times more than that of the Earth's gravitational acceleration — a lot of energy coming from a tiny insect.
"Surprisingly, the beetle can repeat this clicking maneuver without sustaining any significant physical damage," said mechanical science and engineering professor Alison Dunn, also on the research team.
"That pushed us to focus on figuring out what the beetles use for energy storage, release, and dissipation," she continued.
Cross-pollination between fields of engineering, biology
As the lead author of the study, Ophelia Bolmin, points out, "we discovered that the insect uses a phenomenon called snap-buckling – a basic principle of mechanical engineering – to release elastic energy extremely quickly. It is the same principle that you find in jumping popper toys."
Wissa says that "if an engineer wanted to build a device that jumps like a click beetle, they would likely design it the same way nature did. This work turned out to be a great example of how engineering can learn from nature and how nature demonstrates physics and engineering principles."
The study was part of an interdisciplinary collaboration between engineering and biology which re-emphasized how much the engineering world can learn from nature.
"These results are fascinating from an engineering perspective, and for biologists, this work gives us a new perspective on how and why click beetles evolved this way," Alleyne said. "This kind of insight may have never come to light, if not for this interdisciplinary collaboration between engineering and biology. It opens a new door for both fields."