The Billion Ant Mega Colony and the Biggest War on Earth

In nearly every corner of the earth, ants wage war against each other.

Their weapons are what nature gave them. Some have strong armor, deathly stingers, or sharp mandibles.

And then there's this tiny and not very impressive ant,

but it rules the biggest empire any ant has ever built.

A colony spanning continents and fighting wars that leave millions of casualties.

Let's take a look at this unlikely warrioress,

"Linepithema humile" the Argentine ant.

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This story begins in the floodplains around the Paraná River, in South America,

It's a crowded ant megalopolis where dozens of ant species fight for dominance,

including fire ants, army ants and the rather unimpressive Argentine ant.

It measures only 2 to 3 millimeters in length and with its small mandibles,

it's surprising that it survived among its buff competitors.

Their homes are equally unremarkable.

Their colonies range from fairly small to very large and could be found anywhere:

Under logs, in loose leaf litter or the former colonies of other ants.

Here, Argentine ants prepare their most effective weapon against their competitors: bodies.

Most ant species have only one queen to produce ants,

while Argentine ants went all-in on numbers.

For every 120 workers there's one queen,

laying up to 60 eggs a day.

So their colonies grow fast and have millions or billions of individuals.

Teams of queens and workers frequently branch out and found new colonies.

But this strategy has a downside: As colonies grow and produce a lot of offspring,

mutations occur and new colonies adapt to new environments.

Their DNA slowly changes from generation to generation and differences accumulate.

So after a while the ants that left the colony

will become more like distant cousins and start to compete with their mother colony.

In their native South American range, this is how Argentine ants behave.

Within their colonies they are very cooperative and well-organized,

but they fight vicious wars against other Argentine ant colonies and other ant species

With equally strong opponents on every side,

the Argentine ant became extremely aggressive, fighting for every inch of ground.

But it could never dominate its neighbours... until humans showed up.

We did what humans do and transported things around the world by ship.

On one of them, a few Argentine ant queens hitched a ride as stowaways

from South America to Madeira and New Orleans.

The Argentine ants suddenly found themselves in a strange world.

Instead of being surrounded by deadly enemies,