If you are still confused, I highly recommend watching Richard Dawkins explaining it here.īombardier beetle (Brachinus bayardi), Central Coastal Plain, Israel. However, it can be easily demonstrated that by gradually increasing the concentration of hydrogen peroxide this defense could evolve in incremental steps without risking the beetles’ existence. This complex defense mechanism was used by creationists as an example for intelligent design in debates against evolution.
To us humans (=entomologists who collect the beetles with bare hands) the damage it causes is not so severe, usually nothing but a small stain of burnt tissue, but the effect is coupled with a startling popping sound, and that might be enough for the beetle to escape from a large predator. It can momentarily paralyze or even kill arthropod enemies, such as ants and spiders.
Then all the beetle has to do is to aim its “nozzle” and fire! The result is a smoke cloud of chemicals at extremely high temperatures. The chemical reaction starts inside the chamber with temperatures reaching 100☌, and the high-pressure buildup causes the explosion. This mixture, when comes in contact with a catalyst, turns highly combustible due to the oxidation of hydroquinone and the breakdown of hydrogen peroxide to oxygen and water. In short, when provoked the beetle releases two chemicals, hydroquinone and hydrogen peroxide, into a chamber in its abdomen. Much has been written about the mechanics and evolution of the beetles’ chemical defense. Two common species of bombardier beetles from Israel: left – Brachinus alexandri right – Brachinus berytensis