Long before humans planted crops like wheat or rice, ants were already farming. These tiny animals have been cultivating fungi for millions of years, developing a system that rivals our own agriculture in complexity. New research led by entomologist Ted Schultz from the Smithsonian’s National Museum of Natural History traces this practice back 66 million years, right after the asteroid that wiped out the dinosaurs.
In a study, published earlier this month in Science, Schultz and his team used genetic data to uncover the early stages of this farming relationship. After the asteroid impact ended the Cretaceous period, plants across the globe began dying. But fungi thrived, feeding on decaying plant material. For ants, this provided the ideal conditions to start cultivating fungi as a reliable food source. Schultz explained that the aftermath of the asteroid impact created ideal conditions for fungi to flourish. While it was a disaster for plants and dinosaurs, it created new opportunities for the organisms studied by the researchers.
The study revealed that 66 million years ago, ants began collecting organic debris to fuel fungal growth. This was the beginning of ant farming. Over time, their agriculture became more specialised. Around 27 million years ago, as the planet’s climate cooled, ants domesticated certain fungi. These species became fully dependent on the ants for survival, while the ants relied on them for food.
Similar to humans domesticating crops, ants took their fungi from tropical forests into drier environments. These isolated fungi became reliant on the ants’ care in the new, more arid habitats. Leafcutter ants, for example, now grow a specific fungus that produces nutritious food bodies called gongylidia, which are used to feed their young.
Ants also practice many behaviours that mirror human farming. They weed their fungal gardens, use bacteria on their bodies to apply antibiotics, and even pass down their crops to future generations. When a new queen establishes a colony, she carries a piece of her mother’s fungal garden to start the next farm.
Currently, there are 247 species of fungus-farming ants found across the Americas. These species are all descended from the first ants that began farming after the asteroid impact. Leafcutter ants were first observed farming fungi 150 years ago by naturalists, and Schultz’s study adds new depth to this discovery, using advanced genetic tools to map out their evolutionary history.
Why did ants start farming? Schultz believes the asteroid played a major role. When the dust and debris from the impact blocked out the sun, many plants and the animals that fed on them died off. Fungi, however, thrived in the dead vegetation. Ants, already familiar with fungi, began farming them, setting off a relationship that has lasted for millions of years.
The research also highlights a key moment 27 million years ago, when ants began practicing “higher” agriculture, fully domesticating fungi that could no longer live independently. This advanced farming allowed ants to thrive in new environments where their crops depended on carefully controlled conditions. Despite facing challenges that human farmers also face, such as managing disease in their monocultures, ants have maintained a stable farming system.
Schultz points out that while human monocultures are vulnerable to crop failure, ants have somehow managed to avoid this, possibly through their use of antibiotics. Researchers are still investigating how ants maintain this balance.
Ant agriculture offers a glimpse into a system that has survived mass extinctions, climate change, and infectious diseases. Schultz believes there is still a lot to uncover about these tiny farmers. He highlights the vast diversity among fungus-farming ants, many of which are still waiting to be discovered. “Ants have been practicing agriculture and fungus farming for much longer than humans have existed, “says Schultz, adding that “we could probably learn something from the agricultural success of these ants over the past 66 million years.”