October 18, 2021

I, Science

The science magazine of Imperial College

Warfare in the ant world is nothing new. From chemical weapons to suicide bombers these insects have done it all before.

Poison is the attack method of choice for most ant species; those that can’t sting spray formic acid instead. Of the stinging ants, the Bullet ant is the most notorious. It has a sting so powerful that men of the Satere-Mawe people of Brazil use them as part of their warrior initiation rite. Just one sting is said to cause waves of intense pain for up to 24 hours.

Species of Carpenter ants however do one better. They have poison filled stomach glands that run along the entire length of their body. When the colony is threatened they can contract their stomach muscles and explode. Covering the enemy in a corrosive glue.

For the ants that don’t have chemical weapons, the jaws are enough. To defend their own colony or to attack someone else’s, the mandibles are used to tear, cut and crush the way to victory. The Trap-Jaw ant species have the world’s fastest bite. They can shut them 2,300 times faster than the blink of an eye.

Biting however, is not the only thing they can do, these ants have also been seen using them as catapults to fling intruders away from the nests. Their huge jaws are even used to propel themselves away from danger.

With such sophisticated weaponry ant battles can be ferocious. Attacking and defending in concert, the ants have evolved sophisticated chemical communications to coordinate their actions. When an ant dies a violent death, it releases alarm pheromones which not only attract ants from a distance but can also triggers aggression in nearby ants.

The battles of the pavement ants for example leave the ground littered with thousands of dead ants every spring. The stakes in these contests are high; in certain species losing a battle can even end in slavery.

The Amazon ant specialises in stealing the pupae of other colonies during their raids. The kidnapped worker ants will the forage, maintain the nest and nurse the young of the Amazon ants.

The writer Henry David Thoreau wrote perhaps the most famous description of ant combat in his book “Life in the woods”. The battle is “deadly combat, yet without any noise that I could hear”.  After watching a black ant decapitate two red ones he ends it with this: “I never learned which party was victorious, nor the cause of the war: but I felt for the rest of that day as if I had had my feelings excited and harrowed by witnessing the struggle, the ferocity and carnage, of a human battle before my door”.

Ant wars have long been compared to human ones and perhaps, when you look at the science behind them, it’s not that difficult to see why.