Myrmelachista schumanni, also known as the lemon ant, is a species of ant that is notable for the creation of Devil's gardens. Using its own herbicide they are able to shape its surroundings.
Leafcutter ants are the principal herbivores in Central and South American rainforests. In the rainforests of the western Amazon, however, a little-studied ant species rivals the leafcutters in its ability to destroy vegetation. Myrmelachista schumanni, lives in large clearings in the rainforest, called devil's gardens, where all but one species of plant are excluded. The non-excluded plant species is Duroia hirsuta, a myrmecophyte in which M. schumanni nests.
The few studies of the mutualism between M. schumanni-D. hirsuta have incorrectly concluded that these clearings are formed by allelopathy on the part of D. hirsuta. It was established that worker ants were injecting leaves with a poison called formic acid and the plants started to die within 24 hours. Formic acid is a toxin common in many ant species; its name actually comes from the Latin for word for ant, formica.
By killing other plants, the ants provide themselves with many nest sites - a long-lasting benefit as the researchers estimate that the largest garden observed, containing 328 trees over 1,300 square metres, is around 800 years old.