The bombardier beetle inhabits North America, Europe, Australia, Africa and South America. These species number over five hundred altogether. Their habitat is mainly grasslands and woodlands with enough ground cover to hide under. The over forty species found in the United States have blue wing coverings and a reddish head with the same hue extending to their legs. The beetles are quite small in size just over half an inch.
Smell plays a crucial role in locating a partner. The ensuing courtship between male and female bombardier beetles is an intricate ritual involves sensory and visual methods. Beetles pair for a short time and once they pair, sperm cells are transmitted to the female for egg fertilization.
The life cycle of the bombardier beetle undergoes a full metamorphosis. It has four stages of development. The female will lay her eggs in moist areas including decaying animal carcasses, underground and rotting plant matter where they would be safe from predators, but not far from a source of food.
After a few days beetle larvae will hatch from the eggs and will tend have a huge appetite. As they start to grow, they molt shedding their exoskeleton to create more room. By the time the larvae have entered the pupal stage they will have molted ten times.
The larva will kick off the pupal stage by weaving a cocoon around itself then lay dormant. This is when the greatest change takes place as the larva starts to take the form of an adult beetle. Once it achieves adulthood it exits the cocoon a fully mature beetle and another life cycle begins anew.
During metamorphosis beetles and their larvae use a number of ways to prevent attacks by predators. These constitute of camouflage, mimicry and active defense as well as toxic emissions. Camouflage is the use of shape and color to merge with the surrounding environment. Mimicry is when an organism shares outward resemblance with another.
Birds prey on the beetles and their larvae. Some birds grab the adult beetles mid flight while some forage for them on the ground where they take cover. These bettles have a life span of about three years and their diet mostly consists of small insects.
The Bombardier beetles violent chemical reaction they deploy as a defense is unique in the insect world. There are two glands located at the back of the abdomen which are separated from each other. When the bombardier beetle deploys the weapon, catalysts from one gland mix with the combined chemicals from its neighboring gland in a compartment next to the opening. This has a nozzle that unleashes the chemical against intruders. A caustic chemical mist of quinones is the resultant reaction. This reaction produces a lot of heat instantly and the mist is ejected out of the nozzle at a temperature of 100 degrees Celsius due to the catalysts that accelerate the reaction.
Any attacking predator gets a facefull of boiling hot chemicals over and over as the bombardier beetle can fire twenty times before running out of juice, literally. It can point the nozzle in any direction to deliver the spray with great precision.