Scientists Find Secret To ‘Uncrushable’ Bug’s Strength

Looking like it was forged in apocalyptic fires, the diabolical ironclad beetle has a formidable reputation for being able to withstand being stabbed or run over by a car.

Now scientists have found a jigsaw-like mechanism in their exoskeletons that helps the little creature tolerate forces up to 39,000 times its own body weight.

Their discovery could have implications for engineering and robotics, experts say, and even challenge the position of cockroaches as models of insect indestructibility.

The beetle, which no longer has its ancestors’ ability to fly away from predators, has developed crush-resistant exoskeletal forewings — called elytra — as a form of protection, according to the new study published in the journal Nature.

The beetle, which is roughly two centimetres (just under an inch) long, is an oak-dwelling fungivore primarily residing on the western coast of North America.

In spite of its ferocious name, it tends to scuttle into a hiding place or play dead when attacked, helped by its rough textured, craggy black body that gives it the appearance of a small rock.

“Beyond feigning death, this beetle has a remarkable ability to withstand crushing and piercing strikes from predators, and even the occasional automobile,” the study said.

It said they are so tough that entomologists often bend the steel pins they use when they try to mount the beetles in display cases.

Scientists from the United States and Japan looked at the structure of the beetle’s elytra, which allow it to withstand forces of up to 149 newtons — approximately 39,000 times its body weight.

They found was significantly more than other similar beetles could tolerate.

Facts about the diabolical ironclad beetle. Facts about the diabolical ironclad beetle. Photo: AFP / John SAEKI

Using advanced imaging techniques, the researchers saw that the beetle has a series of interlocked jigsaw-shaped joints in its elytra and found that the shape of these blades and their laminated microstructure acted to toughen the exoskeleton.

They concluded that the strong yet flexible structure allows the beetles to hide under rocks or contort themselves into tight spaces in tree bark for shelter, bearing extra weight without damaging their internal organs.

The researchers then used 3D printing and simulations to investigate whether this geometric structure could be used as a mechanical fastener for joining different materials — such as plastics and metal — similar to that required in turbines in the aerospace industry.

The study found that these diabolical ironclad beetle-inspired designs provided enhanced strength and significantly increased toughness compared to a commonly used engineering joint.

Po-Yu Chen, in the Department of Materials Science and Engineering at Taiwan’s National Tsing Hua University, said the weight the insect was able to withstand was roughly 10 times higher than the biting forces generated by potential predators.

“Cockroaches have a similar shape-changing ability, which has inspired the design of a compressible robot that can squeeze into, and move within, tight spaces. Such robots could be used to search for survivors in collapsed buildings after disasters,” he said in a commentary in Nature.

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Meet the Diabolical Ironclad Beetle. It’s Almost Uncrushable.

In 2015, Jesus Rivera filmed a very unusual science experiment for posterity.

On the asphalt of a sun-soaked parking lot, he placed a mottled black beetle on a pillow of dirt and had a colleague run it over with a Toyota Camry. Twice.

Just about any other bug would have died. This one, a species called Phloeodes diabolicus, did not.

“Yeah, it’s still alive,” Dr. Rivera narrated matter-of-factly, as he prodded the still-intact beetle on the video. “It’s playing dead. But it’s still alive.”

Bashed beneath the wheels of a 3,500-pound sedan, the inch-long insect made it through without a scratch. It was a seemingly impossible physical puzzle that Dr. Rivera spent his doctoral career obsessively trying to solve.

Some five years later, he and his colleagues have figured out how this unbreakable bug earned its colloquial name: the diabolical ironclad beetle. Evolution has given the insect an exterior that can hold its own against a force 39,000 times its body weight — the equivalent of a 150-pound person resisting the crush of about 25 blue whales.

“That would jellify a human,” said David Kisailus, an engineer at the University of California, Irvine, who mentored Dr. Rivera’s work.

The impressive armor of these insects, which are found primarily on the west coast of North America, most likely evolved to allow the flightless, fungus-munching bugs to safely wriggle under rocks and fend off the pecks and nips of birds and rodents. But understanding what makes the beetle so diabolical and ironclad could aid development of synthetic products for use in construction or aeronautics, according to a study published Wednesday in the journal Nature.

After his automobile-based field testing, Dr. Rivera and his fellow researchers focused most of their attention on laboratory experiments. They assessed the tensile strength and composition of the beetle’s exterior with a suite of ultrasensitive instruments. The ironclad’s exoskeleton, they found, was packed with proteins that seemed to enhance its durability.

It was also cleverly structured: Evolved from a pair of now-defunct forewings, the exoskeleton stretched across the insect’s back and hooked into a separate structure sheathing the insect’s belly, encasing the beetle in a shell with an airy buffer underneath.

Dr. Rivera compared the arrangement to an industrial-strength egg, with the yolk sloshing gently against a cushion of whites. “You can compress the shell without the yolk, or the organs, getting squished,” he said. Pressed from above, the exoskeleton would bow out slightly at the sides with just enough strength and flexibility to protect the delicate tissues within.

And where the two halves of the exoskeleton met atop the insect’s back, they interlocked like the pieces of a jigsaw puzzle. “That provides strength at this interface,” Dr. Kisailus said.

A closer look at the exoskeleton’s interlocking lobes also revealed they each had an internal Russian doll architecture — a series of concentric layers that faithfully mirrored the shapes that contained them.

“Having these layers helps toughen the joint,” said Talia Moore, a roboticist and evolutionary biologist at

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How This Uncrushable Beetle Can Survive Being Run Over by a Car

A diabolical ironclad beetle.

A diabolical ironclad beetle.
Image: David Kisailus/UCI

The diabolical ironclad beetle, in addition to having one of the coolest names in the animal kingdom, boasts one of the toughest natural exoskeletons. A team of scientists has finally figured out the secret behind this extra durable armor and how these insects can survive getting run over by a car.

As wise people often say, a reed that bends in the wind is stronger than a mighty tree that breaks during a storm. New research published today in Nature suggests the diabolical ironclad beetle (Phloeodes diabolicus) is an adherent of these sage words. Their exoskeletons are extra tough, but when the pressure literally gets to be too much, their protective shells take on an elastic quality that results in a kind of stretching rather than breaking.

The scientists who made this discovery—a team from Purdue University and the University of California-Irvine—say the unique strategy employed by the diabolical ironclad beetle could inspire the creation of innovative materials, namely components capable of dissipating energy to prevent catastrophic breakage. David Kisailus, a professor of materials science and engineering at Purdue, led the new research.

Found in the U.S. southwest, the diabolical ironclad beetle likes to hide under rocks and squeeze behind tree bark. These beetles cannot fly, so they’ve developed a pair of interesting defensive strategies to protect themselves against predators such as birds, rodents, and lizards. In addition to playing dead (a classic and effective strategy in its own right), these tank-like bugs are equipped with one of the toughest shells known to science. So strong is this exoskeleton that these beetles can survive getting run over by a car. More practically, this shell protects their internal organs when, say, they’re getting pecked at by birds.

To better understand these beetles and their durable exoskeletons, the researchers prodded the limits of this armor, studied it with microscopes and CT scanners, and even 3D-printed their own versions to test their theories.

Experiments showed that diabolical ironclad beetles can withstand an applied force of 150 newtons, which is 39,000 times its body weight. If we were to compare this to humans (not a great example, given the vastly different scales involved, but fun nonetheless), that would require a 200-pound person to endure the crush of 7.8 million pounds, according to a Purdue press release. A tire passing overhead would inflict 100 newtons of force, which explains how these beetles can survive run-ins with cars. The researchers say other beetle species can’t handle even half of this load.

Cross section of the medial suture, where two halves of the beetle’s elytra meet. The jigsaw puzzle-like configuration, when stressed and stretched, allows for elasticity, preventing breakage.

Cross section of the medial suture, where two halves of the beetle’s elytra meet. The jigsaw puzzle-like configuration, when stressed and stretched, allows for elasticity, preventing breakage.
Image: Jesus Rivera/UCI

Physical analysis of the exoskeleton with microscopes and CT scanners showed that the key to this durability lies in this creature’s elytra. In flying beetles, elytra serve as the protective wing-cases for their hindwings (in ladybugs, elytra

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