Ants are some of the most socially complex animals on Earth, known for constructing giant nests capable of housing several million individuals, says Will Newton.
Inside these nests are elaborate tunnel networks connected to thousands of climate-controlled rooms, resembling a structure not too dissimilar to a London office block. While these structures are impressive, it’s the ‘fungus gardens’ some species of ants cultivate inside of their nests that are truly mind-boggling.
- It floats, it's larger than a dinner plate and it's made up of more than 100,000 individuals
- They look like ants, they act like ants – but these destructive, house-wrecking little terrors are no ants
More than 200 species of ants are known to farm fungus, and they do this by chewing leaves into a pulp before spreading it across their gardens to stimulate fungus growth.
In the first few days of a new colony, the queen does all of the gardening work, fertilising her plot with fecal liquid. After a few weeks, this messy work is passed onto the workers and fungus begins growing at a much faster rate, to the point where it becomes a reliable food source for the colony.
The largest fungal farms are built by leafcutter ants belonging to the New World genus, Atta. There are 55 different species of leafcutter ants, but it’s Atta laevigata that holds the record for constructing the largest-ever, animal-built fungal farm.
- It spans 6000 km of the coasts of Portugal, Spain, France and Italy – the animal that builds cities
- It stretches 106 square metres and spans two countries – and it's home to over one hundred thousand scuttling residents
A colony of this species created a nest that covered 67m², which is roughly the size of a small apartment. This nest contained 1,920 chambers, 238 of which were occupied by fungus gardens.
To measure the size of this nest, researchers poured concrete into it - thankfully once it had been abandoned. This created a cast of the interior that they were able to examine and measure, though it didn’t capture the true extent of the colony’s fungus farming network.
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While nests are occupied, they’re difficult to measure accurately. According to reports, the central mound of a leafcutter ant nest can grow to more than 30m across, with smaller radiating mounds spreading out to a radius of 80m. Together, these mounds can occupy a space that’s roughly the size of two tennis courts (or 600m²).
In 2024, a study published in the journal Science analysed genetic data from hundreds of species of ants and fungi to create an evolutionary timeline of ant agriculture. They discovered ants began farming fungi 66 million years ago, just after a 15km-wide asteroid struck Earth.
This asteroid caused widespread destruction and wiped out the non-avian dinosaurs, but it also created ideal conditions for fungi to thrive and, according to the study, set ants on the path towards agriculture. To put this into perspective, we - Homo sapiens - only began farming 12,000 years ago.
Ants aren’t the only insects known to farm fungus, termites do too. There are roughly twice as many fungus-farming termites as there are ants, and their methods of production are arguably even more gross.
The workers will eat decaying plant material, excrete it, and use the resulting fecal pellets to create a ‘fungus comb’, which fungal spores (often from Termitomyces) are deposited onto. Like ants, they’ll constantly tend to these fungus combs, relying on them as a main source of food.
Not wanting anything to go to waste, termites eat their fungus combs once their fungal crops are exhausted, recycling the fecal material for future harvests.
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Top image: leafcutter ant by Mara & Moritz Wolf/Getty
