Charles Darwin was a man inordinately fond of beetles. He once caught a rare specimen in one hand, when another, even more remarkable, beetle showed up. He snatched that one up with his other hand. Suddenly, an extraordinary third species crawled past. Darwin, in despair over losing any of them, popped the first one in his mouth. With “unspeakable disgust and pain” he discovered it was a Bombardier Beetle—the only known creature to mix a boiling hot chemical explosion inside its own body. As it squirted livid acid down his throat, he spit the “little inconsiderate beast” out, and all three beetles made their getaway. The Bombardier is a six-legged tank, fitted with two little weapons of destruction: a pair of deadly, swiveling rocket launchers, firing high-pressure clouds of hot, acrid gas to injure shrews, birds, and frogs, and kill would-be invertebrate predators. So, what can we learn from this acerbic little bug? Read on to learn more in our latest installation of The Biomimicry Manual.
Producing a boiling poison inside your body on demand is a major feat of engineering, but the Bombardier’s spray mechanism is nothing short of genius. In fact, creationists argue the beetles’ internal design is so irreducibly complex that it must be the product of ‘intelligent design’ by a higher being.
It was Darwin himself who brilliantly realized that each exquisitely perfected species has honed its craft and form over millions and even billions of years of trial and error. Today, biomimicry is the art and science of studying nature’s perfectly efficient, eco-friendly, and multi-purpose innovations, hoping to borrow their long-term sustainable ideas for ourselves. After all, the ones that got it wrong are extinct!
The Bombardier’s solution is so good that it apparently evolved twice, completely independently. And, there are at least 500 species of Bombardier Beetles, many using different mechanisms or chemistry. They can control the direction, strength, and speed of their spray with incredible accuracy. In South Africa, they are known as “eye-pissers.” Because if you look too close, you’re sure to get an eyeful.
How do they do it? Special cells inside the beetle produce hydroquinones and hydrogen peroxide. These collect in a reservoir, which opens into a tiny, but indestructible, combustion chamber rivaling a homemade pressure-cooker bomb. A muscle-controlled valve separates the reservoir from the chamber, opening to allow the chemicals in, and closing to allow gases to build pressure.
The interior of the bombshell chamber is lined with special enzyme-secreting cells that break down the chemicals, releasing oxygen and generating heat. The boiling fluid creates high pressure vapors that force open the exit valve at the tip of the abdomen. Hot liquid explodes out in a powerful burst of venomous steam that would kill the beetle if it happened all at once. Instead, the reaction is spread over some 70 imperceptibly rapid bursts.
You can probably imagine the applications inspired by this remarkable adaptation. The automotive, aviation, spacecraft, medical, fire control, and consumer industries could all apply these technically advanced, eco-friendly spray systems. Everything from efficient fuel injection to improved drug delivery systems, engines, fire extinguishers, and even asthma inhalers could create more using less with this bio-inspired technology.
But… don’t put them in your mouth.
An evolutionary biologist, writer, sustainability expert, and passionate biomimicry professional in the Biomimicry 3.8 BPro certification program, Dr. Tamsin Woolley-Barker blogs at BioInspired Ink and serves as Content Developer for the California Association of Museums‘ Green Museums Initiative. She is working on a book about organizational transformation inspired by nature.