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.
While ants are usually highly territorial, those living within each super-colony are tolerant of one another, even if they live tens or hundreds of kilometres apart.
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.