With one of the most awe-inspiring names in the animal kingdom, one formidable insect is the diabolical ironclad beetle. Sometimes, birds, lizards and rodents attempt to make a meal of it, but rarely succeed. Run a car over it, and the critter lives on.
Researchers at the University of California, Irvine and other institutions disclose the material components and their nano and microscale blueprints that make the organism so indestructible in a paper published in Nature (‘Toughening mechanisms of the elytra of the diabolical ironclad beetle’), while also showing how engineers can benefit from these designs.
The survival of the beetle depends on two main factors: its ability to play dead convincingly, and an exoskeleton that is one of the biological world’s strongest, most crush-resistant structures known to exist.
“The ironclad is a terrestrial beetle, so it’s not lightweight and fast but built more like a little tank,” said principle investigator and corresponding author David Kisailus, UCI professor of materials science & engineering. “That’s its adaptation: It can’t fly away, so it just stays put and lets its specially designed armor take the abuse until the predator gives up.”
In its U.S. desert habitat. The beetle can be found under rocks and in trees in the southwest, squeezed between the bark and the trunk, another explanation why it must have a robust exterior.
Lead author Jesus Rivera, a graduate student in Kisailus’ lab during the project who has since earned his Ph.D., first heard of these species in 2015 during a visit to the renowned entomology museum at UC Riverside, where he and Kisailus were working at the time. Rivera collected the beetles from sites around the campus of the Inland Empire and took them back to the laboratory of Kisailus to carry out compression experiments, contrasting the findings with those of other Southern California native species. They find that a power of around 39,000 times its body weight would withstand the diabolical ironclad beetle. The crushing weight of 7.8 million pounds will have to be borne by a 200-pound man to equal this feat.