Whenever we see an insect we go eeeek! Aww! Grouse! This usually happens when someone sees a roach. But these tiny creatures have some of the most amazing mechanisms to protect themselves. Alas that we humans don’t! Point in question is that of the amazing Bombardier Beetle. Their mechanism of defence – to spray potential enemy with a 100°C hot liquid! Now that’s hot.

What are these?

Bombardier Beetles are a group of beetles with more than 500 species found in Africa and Asia.

For people interested in knowing its family background below is the details: 🙂


Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Adelphaga
Subfamily: Paussinae
Tribe: Brachini
Genus: Brachinus
Common Name: Bombardier Beetle

How does it defend itself?

These beetles are mainly ground dwellers i.e., they live on ground for most of their time. Many predators like ants, frogs, spiders (and the list goes on) attack these beetles. One of the basic problem with beetles are that they cannot unfurl their wings in a snap to fly, they must instead unfurl the wing covers called ‘elytra’ to take off in the air. And this, my friend, gives ample time for a predator to have a meal out of this poor fellow. When a spider attacks the beetle turns around with its back facing the spider. Now using the opening of the abdominal tip it sprays (it can spray in any desired direction) a mixture of hot chemical concoction at the spider, which has no way other than to escape from this lil fellow.

Below are two very interesting videos to show you exactly what it does. Check it out!



Mechanism of action? (Complex and interesting)

The intense toxicants produced by these glands include acids, aldehydes, phenols and quinones.

The spray has such a high temperature because of the generation of quinines at the moment of ejection by the mixture of two sets of chemicals ordinarily stored separately in the glands. Each gland consists of two confluent compartments. The bigger one among these called as the storage chamber or reservoir while the smaller one is called the reaction chamber. Secretory cells in the glands produce hydroquinones and hydrogen peroxide which collect in the reservoir. The reservoir opens through a muscle-controlled valve onto a thick walled reaction chamber. This chamber is lined with cells that secrete catalases and peroxidases. When the contents of the reservior are forced into the reaction chamber, the catalases and peroxidases rapidly break down the hydrogen peroxide and catalyze the oxidation of the hydroquinones into p-quinones. These reactions release free oxygen and generate enough heat to bring the mixture to the boiling point and vaporize some part of it (a fifth of it to be exact). The pressure created from the released gasses expels the vapor explosively through openings at the tip of the abdomen.

Picture courtesy: PNAS

Each time it does this it shoots about 70 times very rapidly! The damage caused can be fatal to attacking insects and small creatures and is painful to the human skin.

But why does this creature interest a scientist?

And believe me it is one of the most studied in the recent times. You may ask me why – because the complex spray mechanism could provide the key to significant improvements in aircraft engine design, drug-delivery devices and fire extinguishers and make human life better (shouldn’t we be thankful!).

Aircraft Engine Design: Scientists at the University of Leeds, England, are studying the bombardier beetle’s jet-based defense mechanism to help solve a problem that can occasionally occur with man-made systems operating at high altitudes. They’re studying the beetle in the hope that it will teach them how to reignite a gas turbine aircraft engine in temperatures as low as -50°C after the engine has cut out. The researchers hope to better understand the beetle’s unique pulse combustion and nozzle ejection mechanism. The team, led by Professor of Thermodynamics and Combustion Theory at Leeds, Andy McIntosh, has developed new technology (µMist™) which can be the basis for next generation of more effective and eco-friendly mist carrier systems. The µMist™ spray technology enables droplet size, temperature and velocity to be closely controlled, allowing advancements in a variety of areas where the properties of the mist are critical. Such applications include fuel injection, medical drug delivery systems, fire extinguishers and fire suppression, all of which face major challenges relating to the demands of greater performance and reduced environmental impact.

Professor Andy McIntosh

Drug-Delivery Sytems: Many firms are researching this technology for drug-delivery systems as it could prove far more useful than the mechanically-driven spring technology used in, for example, inhalers. The technology could provide a water-based carrier for propelling drugs, replacing conventional propellants which are potential pollutants.

Car Engine: It could also provide a more energy efficient mechanism for fuel-injection in car engines to substantially increase fuel burning efficiency, improving fuel consumption and minimising exhaust pollution.

Fire Extinguishers: It may even lead designers and scientists to a new generation of fire extinguishers that can both produce either a fine mist or large droplets depending on what type of fire needs to be put out.

I am just amazed at this beautiful creation of GOD, aren’t you?