For your Home
Login or register for the customer portal
© 2025 Rentokil Initial plc and subject to the conditions in the Legal statement
There are a lot of weird and curious insects in the world. Here at Western Exterminator, we make sure that we are the experts in all types of insects, specializing in the ones that can become real pests for your home. However, not all of them are pests. Sometimes you just run across one that is both weird and amazing, showing how diverse and unique nature can be.
There are insects out there with all kinds of interesting defense mechanisms to ward off potential predators. Some have fangs, others have claws, some have stingers or give off a strong and offensive odor. Well, let me introduce you to one that basically has its own explosive weapon built right in: the bombardier beetle, the insect that shoots boiling hot chemicals at potential threats and predators.
What are bombardier beetles?
.webp)
Bombardier beetles are a type of ground beetle known for their unique defense method. They’re usually small, about half an inch long, and can be black or dark brown with reddish legs or markings. These beetles are found in many parts of the world and often live under rocks, logs, or in leaf litter where it’s dark and damp.
The thing that sets the bombardier beetle apart from all of those other insects is the unique developments their bodies have made as a defense. They have developed two chambers within their abdomen. One of them contains the substance known as hydroquinone and the other hydrogen peroxide. The strange thing is that if you were to mix those two substances together in a glass right now – nothing would happen.
The bombardier beetle, however, has evolved a catalyst that is stored within the chamber where the two chemicals mix. Thus, three different things come together to create a reaction. When a threat is detected, such as a predatory insect touching the insect’s body or legs, or you’re a spider, bird, scorpion or another predator, those two chemicals are instantly released into the chamber where the catalyst chemicals then start the reaction.
Why do bombardier beetles spray?
Bombardier beetle spray is a defense method used when the beetle feels threatened. If a predator like a frog, bird, or insect gets too close, the beetle releases a hot chemical spray to protect itself and escape.
What happens then? The two chemicals reach a boiling point via chemical reaction and gas is produced that allows the beetle to “fire” this boiling hot substance into the potential predator. The boiling chemicals can even be directed from the hind end of the beetle-like a small turret and the insect can hit its intended target with amazing accuracy.
If you happen to be an insect much smaller than the beetle, the intensely hot spray can be fatal. If you happen to be human, you might just say “ouch” and let go of the beetle’s leg.
Anatomy of an explosion
No one is sure how the bombardier beetle evolved this particular defense, but other beetles are known to carry chemicals that can be released to help defend against predators. For example, the beetle known as Metrius contractus mixes chemicals and releases a foamy substance onto the skin of potential predators.
The catalysts that trigger the explosive reaction line the walls of the final chamber. The reactions happen in an instant, often accompanied by a soft popping sound.
The chemicals mix with the catalyst and the reaction is what is known as exothermic, which means it gets very hot. The temperature can reach over 200 degrees Fahrenheit! The pressure of the reaction builds up so fast that it must be released and it comes out as a mixture of liquid and gas. The beetle can usually get about 20 sprays before it runs out, which is usually enough to kill predatory insects. The chemicals involved are also irritating to the eyes and respiratory system of anything in its path.
Behavior of bombardier beetles
These types of beetles are found all over the planet except for arctic regions like Antarctica. They like to live in grassy and woodland areas, preferring mild or temperate zones over areas that get cold during the fall and winter.
When it comes to the bombardier beetle diet, these insects are omnivorous. They will eat other, small, insects and will do so even in the larval stage. They like to hunt at night and even have some social tendencies, hanging out with others of its species, when not actively looking for food.
Bombardier beetle vs false bombardier beetle
At a glance, bombardier beetles and false bombardier beetles may look similar, but they’re not the same. The true bombardier beetle is known for its ability to spray a hot chemical blast as a defense. It stores two chemicals in its body that mix and react when released, creating heat and a popping sound.
False bombardier beetles, on the other hand, don’t produce that same chemical spray. They may look similar in shape and color, but their defense is more limited, usually just releasing a bad smell to keep predators away. False bombardier beetles belong to a different group and are often mistaken for the real thing because of their appearance.
Bombardier beetle
False bombardier beetle
Are bombardier beetles dangerous to humans?
No, bombardier beetles are not dangerous to humans. While their spray is strong enough to stop small predators, it doesn’t pose a serious risk to people. The spray might cause mild skin or eye irritation if handled directly, but these beetles are not aggressive and will usually try to escape instead of attacking.
They don’t bite, they don’t carry diseases, and they aren’t a threat to your home or property. As with most insects, it’s best to avoid touching them, but there's no need to worry if you see one outside.
The amazing insect world
Generally, the bombardier beetle is harmless to people. It would be advisable not to handle them if you have sensitive skin or sensitivity to things like hydrogen peroxide or quinones. The beetle is not known to bite, using the firepower it packs to defend instead.
So, the next time you are in your garden, if you see a small colorful beetle and feel tempted to reach down and pick it up, be careful. You might just get a painful surprise.
If you have real insect problems, make sure you contact the experts at Western Exterminator for a free inspection and discussion of your pest-related problems. Call today
Frequently asked questions
Where are bombardier beetles found?
Bombardier beetles are found in many parts of the world, including North America. They prefer damp, dark places like under rocks, logs, or leaf piles and are most active at night.
What are bombardier beetles?
They are small ground beetles known for their ability to spray a hot chemical mix when threatened. This defense makes them one of the most unique beetles in the insect world.
How does their defense spray work?
When attacked, the beetle mixes two chemicals inside its body. The reaction creates heat and pressure, which allows it to shoot out a hot, popping spray that surprises predators.
Are bombardier beetles aggressive?
No, bombardier beetles are not aggressive toward people. They use their spray only as a defense and will usually try to run away first.
What attracts bombardier beetles to my home?
They may come near your home if there are cool, moist areas nearby, like mulch beds, leaf piles, or cracks in foundations. Outdoor lights can also attract the insects they feed on.