Are ants taking over the planet? Well, they’ve definitely spread, and they know which ants are on their colonial “team.” In fact, a single colony consisting of billions of Argentine ants, originally natives of South America, have spread onto every continent save Antarctica, thanks to human activity.

Even more remarkable, the insects can tell which ants are from their own colony, even if they live on different continents. When scientists placed ants from the Argentine colony together, even if they were taken from other countries, they were amiable (i.e., nonviolent) to each other. Contrast that with the aggression ants from separate colonies displayed when they came into contact with each other, according to the BBC:

Argentine ants are renowned for forming large colonies, and for becoming a significant pest, attacking native animals and crops. In Europe, one vast colony of Argentine ants is thought to stretch for 6,000km (3,700 miles) along the Mediterranean coast, while another in the US, known as the ‘Californian large’, extends over 900km along the coast of California. A third huge colony exists on the west coast of Japan….

Ants from the smaller super-colonies were always aggressive to one another. So ants from the west coast of Japan fought their rivals from Kobe, while ants from the European super-colony didn’t get on with those from the Iberian colony. But whenever ants from the main European and Californian super-colonies and those from the largest colony in Japan came into contact, they acted as if they were old friends.

Experts say the ants likely are genetically related, so they recognized the chemical composition of each others’ cuticles.
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