Technology & Science

How this un-crushable beetle survives being run over by a car

It's a beetle that can withstand bird pecks, animal stomps and even being rolled over by a Toyota Camry. Now scientists are studying what the bug's crush-resistant shell could teach them about designing stronger planes and buildings.

Diabolical ironclad beetle's armour design could lead to stronger aircraft

The diabolical ironclad beetle, found in Southern California's woodlands, can withstand compression of about 39,000 times its own weight. ( David Kisailus)

It's a beetle that can withstand bird pecks, animal stomps and even being rolled over by a Toyota Camry. Now scientists are studying what the bug's crush-resistant shell could teach them about designing stronger planes and buildings.

"This beetle is super tough," said Purdue University civil engineer Pablo Zavattieri, who was among a group of researchers that ran over the insect with a car as part of a new study.

So, how does the seemingly indestructible insect do it? The species — aptly named diabolical ironclad beetle — owes its might to an unusual armor that is layered and pieced together like a jigsaw, according to the study by Zavattieri and his colleagues published in Nature on Wednesday. And its design, they say, could help inspire more durable structures and vehicles.

To understand what gives the inch-long beetle its strength, researchers first tested how much squishing it could take. The species, which can be found in Southern California's woodlands, withstood compression of about 39,000 times its own weight.

For a  90-kilogram (200-pound man), that would be like surviving a 3.6-million-kilogram (7.8-million-pound) crush.

Other local beetle species shattered under one-third as much pressure.

Researchers then used electron microscopes and CT scans to examine the beetle's exoskeleton and figure out what made it so strong.

As is often the case for flightless beetles, the species' elytra — a protective case that normally sheaths wings — had strengthened and toughened over time. Up close , scientists realized this cover also benefited from special, jigsaw-like bindings and a layered architecture.

The beetle's elytra — a protective case that normally sheaths wings, were very strong, very tough and had special, jigsaw-like bindings and a layered architecture. (David Kisailus)

When compressed, they found the structure fractured slowly instead of snapping all at once.

"When you pull them apart," Zavattieri said, "it doesn't break catastrophically. It just deforms a little bit. That's crucial for the beetle."

Alternative to pins, bolts, welding

It could also be useful for engineers who design aircraft and other vehicles with a variety of materials such as steel, plastic and plaster. Currently, engineers rely on pins, bolts, welding and adhesives to hold everything together. But those techniques can be prone to degrading.

In the structure of the beetle's shell, nature offers an "interesting and elegant" alternative, Zavattieri said.

Because the beetle-inspired design fractures in a gradual and predictable way, cracks could be more reliably inspected for safety, said Po-Yu Chen, an engineer at Taiwan's National Tsing Hua University not involved in the research.

The beetle study is part of an $8 million US project funded by the U.S. Air Force to explore how the biology of creatures such as mantis shrimp and bighorn sheep could help develop impact-resistant materials.

"We're trying to go beyond what nature has done," said study co-author David Kisailus, a materials scientist and engineer at the University of California, Irvine.

The research is the latest effort to borrow from the natural world to solve human problems, said Brown University evolutionary biologist Colin Donihue, who was not involved in the study. Velcro, for example, was inspired by the hook-like structure of plant burrs. Artificial adhesives took a page from super-clingy gecko feet.

Donihue said endless other traits found in nature could offer insight: "These are adaptations that have evolved over millennia."

Comments

To encourage thoughtful and respectful conversations, first and last names will appear with each submission to CBC/Radio-Canada's online communities (except in children and youth-oriented communities). Pseudonyms will no longer be permitted.

By submitting a comment, you accept that CBC has the right to reproduce and publish that comment in whole or in part, in any manner CBC chooses. Please note that CBC does not endorse the opinions expressed in comments. Comments on this story are moderated according to our Submission Guidelines. Comments are welcome while open. We reserve the right to close comments at any time.

Become a CBC Member

Join the conversationCreate account

Already have an account?

now