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If you stepped on the average insect, it would squish under your foot maybe without you even realizing it.
But one unusual beetle is an extreme exception.
Not only can it survive a stomping—it can survive being run over by a car.
I can’t do that!
It pulls this off with some brilliant engineering.
And in fact, it may even have a lesson or two to teach us about how to build structures
that are light and strong.
This hardcore hero—and this is its actual name—is called the diabolical
ironclad beetle, which is actually a pretty modest-looking beetle native to the desert
of southern California.
But do not be fooled—it has earned every bit of that amazing name.
It’s a lightweight beetle with a skeleton that can support about 39,000 times its body weight.
In part, it achieves that by growing an extremely sturdy exoskeleton.
An exoskeleton is any rigid structure surrounding an organism’s body—like a snail shell
or the outside of a grasshopper.
It’s a defining characteristic of arthropods, a category that includes all animals with
exoskeletons and jointed bodies.
In other words, things like insects, spiders, and crustaceans.
And all these animals use their exoskeletons for both protection and support, so they’re fairly strong.
But the ironclad’s exoskeleton is on a whole other level.
Like other arthropods, it makes its exoskeleton out of chitin, which are long chains of molecules
that pack together to form tough fibers.
They’re interlaced with proteins that are chemically altered so that they become stiff and hard.
But it doesn’t stop there.
The ironclad has an especially high ratio of protein to chitin.
And not only are there more proteins, but they appear to have a lot of cross-links between
them, which are connections that bond one molecular strand to another.
The researchers believe these links help make it stronger, kind of like how a thickly-woven
fabric is generally sturdier than something more thinly-woven.
On top of that, those proteins may help absorb energy, kind of like shock absorbers.
So these adaptations go a long way, but they are not the whole story.
The ironclad also does something much more drastic.
It fuses together the hard coverings on its back.
See, beetles have two symmetrical, lid-like features, known as elytra, and most of the
time, they cover and protect a pair of wings.
But the ironclad doesn’t fly; it lives on the ground.
So over time, evolution fused those two elytra together.
They didn’t just form one solid piece of armor, though.
Instead, they fused together like pieces of a jigsaw puzzle, with interlocking ridges and valleys.
And it is not easy to separate them.
They even have little rod-like structures called microtrichia on the surfaces where
the two sides meet, which likely provide friction in case some pressure does try to force them apart.
Since the two sides hang together so tightly, when the beetle is under a lot of pressure,
the elytra can act like a single sheet of armor.
As a result, pressure gets distributed across the insect’s whole body, so there’s less
strain on any one part.
Still, under extreme pressures, the elytra can separate—but even then, it’s not game over.
The precise shape and angle of the interlocked pieces distribute the force so that the pieces
don’t actually snap—they just pull apart, like joints coming out of socket.
And this separation actually absorbs a lot of the force pushing down on the beetle, so
that it doesn’t have to absorb so much of it with the rest of its body.
Researchers don’t know yet if the beetle can heal yet once its elytra comes apart, so maybe
it can be weakened after an event like this, but at least it’s still alive.
And thanks to this incredible armor, the beetle can withstand about one and a half times the
weight of an average car!
And this is weird because it’s not like the beetle evolved on a highway, which raises the question…
Why bother with such elaborate armor?
And the answer seems to be… because it can’t fly.
As a beetle, being confined to the ground is pretty dangerous.
Like, there are all kinds of things that might want to smush you if you’re stuck on the
ground, or just do it by accident, and if you can’t fly it’s harder to escape things
that want to stab you , like bird beaks… really, a ground-dwelling beetle has it pretty rough.
But thanks to its tough shell, the beetle can just put up with predators’ attempts
to crush or pierce it, and then carry on with its life.
And this strategy might not just be helpful for beetles.
It might also be helpful for us.
In particular, many engineers deal with the ongoing problem of how to attach materials
together without weakening the overall structure.
Like, in airplanes, engineers use fasteners to hold together the parts of the engine.
But fasteners weaken and weigh down the structure and can even cause fractures over time.
Engineers wouldn’t have to worry about fasteners, though, if they could use the jigsaw-type
structures that evolved in the ironclad beetles to connect different parts in airplanes.
This is something researchers are already looking into—not just for planes, but for
other structures as well.
Because, for as much as we humans know, nature is still the unbeatable engineer.
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