Stanford University biologist Megan Frederickson believes that ants — not evil spirits — create these gardens. “A Devil’s garden is a lot like a grove or an orchard and so it has the feel to it like something that has been planted by people,” Frederickson says.

Her research at the Madre Selva Biological Station in Loreto Peru has revealed that a species of ant, Myrmelachista schumanni, is responsible for these mysterious clearings. Because these ants nest and rear their young in only the lemon ant tree, Duroia hirsute, they have developed a gardening “technique” to remove all surrounding vegetation and only allow new lemon ant trees to thrive.

Frederickson and her field assistant, Antonio Coral, observed that worker ants chew holes in the leaves of all the plants they don’t want near their host tree. The ants stick their abdomens in the holes and secrete a few drops of formic acid to kill the unwanted plants, creating space for more lemon ant trees. The untreated saplings began to die within 24 hours, proving it wasn’t the lemon ant tree that was responsible.

With data from a two-year rainforest census, Frederickson and her team calculated that the gardens expand about 7 percent each year. They estimate that the largest garden in their study is 807 years old. That garden measures 1,300 square meters and houses 3 million worker ants and 15,000 queens. With that much competition, the Chuyachaqui may have to go to the devil and live somewhere else.