Humans have been farming crops for thousands of years, but we’re new arrivals to the agricultural scene. Leafcutter ants have been doing the same thing for millions of years.

If you like wildlife documentaries, you’ve probably seen leafcutters before, marching in vividly coloured columns with leaves held aloft in their jaws. These sliced fragments are carried back to the nest and fed to a fungus, which the ants then eat. Neither ant nor fungus can survive without the other. Their partnership has fuelled the leafcutters’ success—they come in more than 40 species, and have among the largest colonies of any ant.

Leafcutter ants are often compared to farmers, and the analogy works on many levels. They apply fertilisers to their crops, in