World’s 1st farmers? Ants started cultivating fungi 66 million years ago

It turns out ants had been cultivating fungi for millions of years before humans began farming.

A new surprising study has discovered that ants began farming fungi around 66 million years ago, shortly after a devastating asteroid impact that killed dinosaurs.

The asteroid impact caused a mass extinction event, wiping out many species. However, for fungi, it was a time of opportunity. They thrived on the abundant dead plant material, creating a favorable environment for ants to exploit.

Ever since then, ants and fungi — two seemingly disparate organisms — have formed a symbiotic relationship that has shaped the course of their evolution.

Smithsonian’s National Museum of Natural History researchers state that this evolutionary partnership became stronger 27 million years ago, and exists even today.

“Ants have been practicing agriculture and fungus farming for much longer than humans have existed,” said Ted Schultz, entomologist and the museum’s curator of ants and the lead author of the new paper.

Schultz has conducted extensive research on the evolutionary history of the ant-fungus symbiosis in the last 35 years.

Genetic samples

Today, leafcutter ants are well-known for their advanced agricultural practices. These tiny insects harvest leaves and bring them back to their underground nests to cultivate a specific type of fungus.

The fungus, known as gongylidia, provides a vital food source for the ants. In return, the ants protect and nurture the fungus, ensuring its survival.

Leafcutter ants are just one example of the many ant species that have developed agricultural systems. Nearly 250 different species of ants in the Americas and Caribbean farm fungi, using a variety of cultivation strategies.

Schultz has conducted over 30 expeditions to study ants and fungi in their natural habitats and has also raised ant colonies in a lab. He and his colleagues have collected thousands of genetic samples, which were essential for the new research.

The team sequenced the genes of 475 fungi and 276 ants.

This led to the creation of an evolutionary tree, which helped pinpoint when ants started farming fungi.

The evolutionary tree

The genetic data revealed a longstanding and deeply intertwined relationship between ants and fungi , dating back 66 million years.

The collision triggered a global catastrophe, filling the atmosphere with dust and blocking sunlight, which disrupted photosynthesis and killed plants.

However, this created favorable conditions for fungi to grow by consuming dead plant material.

“Extinction events can be huge disasters for most organisms, but it can actually be positive for others. At the end of the Cretaceous, dinosaurs did not do very well, but fungi experienced a heyday,” Schultz added.

The abundance of decaying plants provided a rich source of sustenance for many fungi, which, in turn, increased their chances of encountering ants that were actively foraging in the same environment. The ancient ants began to use the fungi for food.

The study found that it took ants approximately 40 million years to develop “advanced agriculture.” This occurred around 27 million years ago when a cooling climate created drier habitats in South America.

Ants that brought fungi into these drier areas isolated the fungi from their wild populations, making them dependent on ants for survival. This led to the development of higher agriculture, as seen in leafcutter ants today.

“The ants domesticated these fungi in the same way that humans domesticated crops,” Schultz concluded in the press release.

The findings were published in the journal Science.