UC Irvine researchers study beetle that can survive being run over by a car

It’s unclear what the unnamed diabolical ironclad beetle thought when it was run over by a Toyota Camry.

Or what went through his little beetle brain when the car passed over him a second time.

Likely, the little beetle didn’t think much of the incident. Not because it’s a beetle and beetles aren’t believed to be deep thinkers. But because its strong exoskeleton kept it comfortably safe from any damage.

The experiment it was involved in was part of a years-long study by UCI professor and principle investigator David Kisailus, who has been seeking to identify what makes the beetle so strong.

“This diabolical ironclad beetle is not able to fly away, so it’s adapted to living on the ground,” Kisailus said. “So since it can’t fly away from predation, it pretty much has to stand there and take it right from any type of predation.”

Kisailus’ lab has found that it takes three times more force to compress the diabolical beetle than any other, which is about 150 Newtons or 39,000 times its body weight. To put that into perspective, squeezing as hard as you can with your thumb and forefinger generates about 25 Newtons of force.

Kisailus’ lab has been studying the beetle for about five years.

It started when Jesus Rivera, who has worked at Kisailus’ lab since 2015, was told of the beetle’s near-mythic strength by a curator at an entomology museum at UC Riverside, where Kisailus’ lab used to be based.

“We had to test the folklore,” Kisailus said.

Once the beetle survived being run over twice, the researchers knew they needed to delve into the design of the exoskeleton.

Through studying the beetle microscopically and spectroscopically, the researchers found that the exoskeleton’s elytra are like a solid shield, joined together like a jigsaw puzzle. In typical aerial beetles, elytra are the forewing blades that open and close to keep the wings safe from harm.

“That night, I actually went out to Rite Aid and bought a 100-piece jigsaw puzzle,” Kisailus said. “I brought it to our group meeting the next day, and my students thought I was nuts, you know, what are you doing? And I said, come on, take a look at this microscope image, and then take a look at this puzzle, it’s exactly the same.”

After determining the cause of the beetle’s strength, Kisailus’ lab is working on applying the biological structure of the beetle to things humans engineer.

Kisailus said the structure could be used to make aircraft more resistant to damage.

“The aircraft industry, they use what are called rivets or fasteners or adhesives to put things together,” Kisailus said. “So, when you talk about metal and a composite, they often will use what’s called an aircraft fastener, which is kind of this titanium bolt that bolts these two parts together. And that’s great, it holds it together, and it does the job. It’s strong ... But when it failed, it failed catastrophic.”

In comparing that with the diabolical beetle’s jigsaw structure, it was about 105% tougher than the aircraft standard.

This is typical work for Kisailus’ lab.

The lab studies extremophiles, which are organisms that do something interesting mechanically, thermally or optically. The lab has studied plants that survive fires and the mantis shrimp, a crustacean that smashes its prey faster than a .22-caliber bullet.

“We try to understand how they’re built and how they work, and then translate that to real engineering application by a process called biomimicry,” Kisailus said.

Biomimicry is designing and producing structures or systems that are modeled after biological structures.

The lab has received funding from the U.S. Air Force to work on improving the structure of military drones. Kisailus said findings from studying the mantis shrimp and diabolical beetle could come in handy when redesigning the drones.

Rivera said nature is the best engineer.

“Nature has worked with these laminated composite structures for hundreds of millions of years, and we’ve only recently been using these for engineering application,” he said. “So what can we actually learn from these organisms, or these designs, and then apply them to these engineering structures.”

Rivera, who has a PhD from UC Riverside, has been working on the beetle study since the beginning. He said it’s been rewarding to apply natural designs to industries like aerospace, automotive and defense.

“Typically, nature is able to take readily available resources ... carbon proteins, things like that, and architect them in a way where they’re actually stronger than their constituent material,” Rivera said.

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