Around 66 million years ago, when an asteroid collided with Earth and triggered a mass extinction, wiping out the dinosaurs, an unexpected alliance began to form. As the planet was left littered with decaying plant matter, a unique partnership between ants and fungi took root.
The catastrophic event that reshaped life on Earth also set the stage for fungi to thrive. This abundance of decaying organic material offered a new opportunity for certain ant species. Researchers have now discovered that ants began cultivating fungi during this period, initiating an evolutionary relationship that mirrors the agricultural practices humans would develop millions of years later.
Over time, this relationship evolved and strengthened. By 27 million years ago, ants had refined their farming techniques, similar to the way humans would later domesticate crops. A new study published in Science analyzed genetic data from numerous species of ants and fungi, creating detailed evolutionary timelines that show how ant agriculture developed over millennia.
“Ants have been practicing agriculture and fungus farming for much longer than humans have existed,” said Ted Schultz, the lead author of the study. Schultz believes that humans could potentially learn from the long-standing agricultural success of these ants.
In the Americas and the Caribbean alone, there are nearly 250 species of fungi-farming ants, all of which employ one of four different farming systems. One of the most sophisticated systems is practiced by leafcutter ants, which harvest fresh vegetation to feed their fungi. In return, the fungi produce specialized structures, known as gongylidia, that serve as food for the ants. This intricate system supports massive colonies of millions of ants.
The relationship between ants and their cultivated fungi is so finely tuned that ants actively manage their fungal gardens. Like human farmers, they weed out harmful bacteria and fungi, transferring healthy fungal matter to fresh patches to encourage growth. Some ant species even carry bacteria that produce natural antibiotics, helping to protect their crops from diseases.
“Somehow, over the course of 66 million years, they’ve been able to continue to control crop disease and develop antibiotics that continue to be effective,” Schultz shared. “We’ve only been using antibiotics and herbicides for less than 100 years and we have major problems keeping up with resistance and developing new antibiotics.”
This groundbreaking study is the culmination of Schultz’s 35 years of research into the ant-fungus relationship. His team collected thousands of genetic samples from Central and South America to create the largest-ever genetic dataset of fungus-farming ants. By comparing wild fungal species with those cultivated by ants, researchers concluded that these insects began farming fungi shortly after the asteroid impact that marked the end of the Cretaceous period.
While the extinction event was disastrous for many species, it opened new ecological niches for others. “What was a catastrophe for some organisms 66 million years ago was a golden era for others,” Schultz explained. “Photosynthesis was shut down by the asteroid, and a bunch of plants were driven to extinction. But some fungi grow in decaying plant matter—it was a great time for them.”
This abundance of fungi likely attracted ants, who recognized fungi as a reliable food source. Over time, as climates shifted and the world changed, some ant species adapted their farming practices to suit drier, more arid environments. This led to the development of what researchers call “higher agriculture,” in which ants isolated their fungi from wild populations, creating a mutual dependency. This ancient agricultural relationship between ants and fungi continues to flourish today, offering new insights into evolutionary biology and sustainable farming practices.