A native of the desert habitat in Southern California, the diabetic Ironclad beetle has an exoskeleton that is one of the most difficult, most crush-resistant structures known to exist in the animal kingdom. UCI researchers created a project to study the components and architectures responsible for making animals so indestructible. Credit: David Kisilus / UCI
University of California, Irvine Materials Scientists have discovered the secrets of the almost indestructible insect design.
The diabetic ironclad beetle of Southern California has an exoskeleton so tough, it can even survive driving by car.
Along with one of the more awe-inspiring names in the animal kingdom, the diabolical ironclad beetle is a terrifying insect. Birds, lizards and rats often try to make food but rarely succeed. Drive with him, and the critic stays alive.
The survival of the beetle depends on two main factors: its ability to play the role of a sure dead, and one of the most difficult, most crush-resistant structures to exist in the biological world, the exoskeleton. In a paper published today in Nature, Researchers at the University of California, Irvine and other institutions show the physical components – and their nano- and microscale blueprints – that make organisms so indestructible, while also showing how engineers can benefit from these compositions.
“Ironclade is a terrestrial beetle, so it’s not lightweight and fast, but it’s built a little like a tank,” said David Kissilus, a UCI professor of materials science and engineering, a theory researcher and corresponding author. “It’s his adaptation: he can’t fly, so he just stays put and lets the hunter misuse his specially designed armor until he gives up.”
U.S. In its desert habitat in the southwest, the beetle can be found under rocks and in trees, squeezed between its bark and trunk – another reason it needs to have a durable exterior.
The diabolical ironclad beetle is so tough, it can survive driving a car with a force of 100 Newtons. Engineers from Purdue University and UC-Irvine came together to unlock the beetle’s secrets. Credit: Purdue University / Erin Isterling
Leading author Jesus Rivera, a graduate student in Kisilus’ lab, first learned about these organisms during a visit to UC Riverside’s famous Entomology Museum in 2015, where he and Kisilus were working at the time. Rivera collected beetles from sites around the Inland Empire campus and brought them back to Kyssilus’ lab to perform compression tests, comparing the results of other species in Southern California. They found that a diabetic ironclad beetle could withstand a force of about 39,000 times its body weight. The 200-pound man will have to endure a crushing weight of 7.8 million pounds to equal this achievement.
While conducting a series of high-resolution microscopic and spectroscopic evaluations, Rivera and Kisalius learned that the secret of the bug lies in the physical structure and architecture of its exoskeleton, in particular, its ultra. In the air beetle, the Eletra is a flying ring blade designed to protect and keep the flight wings safe from bacteria, dissection and other sources of damage. Ironclad’s Ultra has evolved to be a solid, protective ield.
A cross section of the medial seam, where two parts of the diabetic ironclad beetle’s ultra meat, show a puzzle piece configuration that is the key to the insect’s incredible durability. Credit: Jesus Riviera / UCI
It was analyzed by Kisalius and Rivera that Eltra contains chitin layers, fibrous material, and protein matrix. Together with a group led by Atsushi Arkaki of Tokyo University of Agriculture and Technology AG and his graduate student Satoshi Murata, they examined the chemical composition of the exoskeleton of a light-flying beetle and compared it to its terrestrial subject. The outer layer of the diabolical ironclad beetle has a significantly higher ration concentration of protein – about 10 percent more by weight – which researchers suggest contributes to the increased hardness of the ultra.
The team also examined the geometry of the medial seam connecting the two parts of the Elitera and found that they looked like interlocking pieces of a jigsaw puzzle. Rivera created a device inside an electron microscope to observe how these connections react under compression, similar to how they react in nature. The results of his experiment showed that, instead of flickering on the “neck” region of the interlocks, the microstructure of the Eletra blade gives way through delamination or layered fracturing.
“When you break a puzzle piece, you expect it to be in the neck part, the thinnest part,” Kisils said. “But we don’t see catastrophic divisions in this species of beetle. Instead, it delays, providing a more impressive failure of the constitution. “
Further microscopic examination by Rivera revealed that the outer surface of this blade showed an array of rod-like elements called microtrichia which scientists believe act as a friction pad and resist slippage.
Kisellius sent Riviera along with Dula Parkinson and Harold Barnard to work on advanced light sources at the Law Rains Berkeley National Laboratory, where they performed high-resolution experiments to direct changes in real-time structure using extremely powerful X-rays.
The results confirmed that during compression, the sutures – instead of breaking in the thinnest position – are slowly delaminated without catastrophic failure. They also recognized that geometry, physical components, and their assembly were crucial to making the beetle’s exoskeleton so tough and strong.
To further their experimental observations, Riviera and co-authors Miriam Hosseini and David Restrepo – both from Pablo Zavattiri’s lab at Purdue University – use 3D printing techniques to create their own compositions of the same design. They ran tests that showed the configuration provided maximum strength and durability. Purdue team models showed that geometry not only enables a stronger interlock, but lamination provides a more reliable interface.
Kissils said he sees great promise in the exoskeleton and other biological systems of the Ironclad Beetle for new substances to benefit humanity. His lab makes advanced, fiber-reinforced composite materials based on these characteristics, and he envisions the development of novel ways of fusing aircraft parts without the use of conventional rivets and fasteners, representing the stress point in each structure.
His team, including UC Riverside undergraduate Drago Vasile, mimicked the elliptical, interlocking fragments of the diabetic ironclad beetle with carbon fiber-reinforced plastic. They joined their biomimetic composites in aluminum couplings and conducted mechanical testing to determine if there were any advantages against standard aerospace fasteners in binding different materials. Sure enough, scientists found that the beetle-induced structure was both stronger and stiffer than current engineering fasteners.
“This study really connects the fields of biology, physics, mechanics and materials science to engineering applications, which you don’t usually see in research,” Kisils said. “Fortunately, this program, which is sponsored by the Air Force, really enables us to form these multi-disciplinary teams, which helped connect the dots leading to this remarkable discovery.”
For more information on this research read Design Secrets of Car Driven Insects.
References: Jesus Riviera, Mary Sadat Hossini, David Restrapo, Satoshi Murata, Drago Vasile, Dilworth Y. Parkinson, Harold S. Barnard, Atsushi Arakaki, Pablo Zavettiari and David Kisilius “The Obscure Methods of the Diabetic Ironclad Beetle Ultra” 21 October October 2020, Nature.
DOI: 10.1038 / s41586-020-2813-8
This project – called the U.S. Department of Scientific Research. Air Force Office Fees, U.S. Army Research Office Fees, U.S. Supported by the Department of Energy and the Global Innovation Research – Institute of Agriculture and Technology at the University of Tokyo. San Antonio.
