But it now appears that billions of Argentine ants around the world all actually belong to one single global mega-colony.
The team selected wild ants from the main European super-colony, from another smaller one called the Catalonian super-colony which lives on the Iberian coast, the Californian super-colony and from the super-colony in west Japan, as well as another in Kobe, Japan.
They then matched up the ants in a series of one-on-one tests to see how aggressive individuals from different colonies would be to one another.
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.
From the Upcoming ueue, submitted by .