When Life Gives You Asteroids, Start An Agricultural Revolution

How an Asteroid Helped Ants Become Farmers 66 Million Years Ago

Today, I’ll become a bit vulnerable and share a personal story that I’m borderline ashamed of.

I started a Biology degree because I became fascinated with evolution. The fact that all organisms on Earth evolved from pretty much nothing, a soup of scattered molecules that, over time, found a way to organize and replicate themselves. Pure genius.

But we also see Earth’s immense diversity of forms, shapes, and life strategies. Each organism comes from a different path or evolutionary lineage, each unique and successful since they’ve all made it to the present time, right?

Well, this last bit was a concept I wasn’t so familiar with. So, when observing a group of marine worms under the microscope, I asked my Zoology professor about the meaning of some creatures evolving oppositely to how humans have evolved. Wouldn’t that be detrimental to them?

In retrospect, I understand that he must have listened to me in disbelief. But he kept his cool and explained that that was an anthropocentric vision of evolution and life. Why would all life forms aim to form civilizations? In biology, we define success as surviving in a niche in which you are competitive and well-adapted for millions of years at a time.

Being alive in the present moment is a great success for a species. Is building civilizations, flushing toilets, and talking machines the only measure of success? Isn’t a coral spreading its spores to other rocks and keeping its colony alive for decades an equally successful evolutionary story?

Besides, we need all types of forms for the Earth to survive. Each species serves a very specific role. Remove any of them, and the ecosystem will crumble. Remove too many, and the ecosystem may collapse entirely.

But there’s something else. There are some strategies that we think only humans have adapted. However, if we look into the animal kingdom or even the fossil record, we may find a completely different story. Did you know we are not the only ones to “invent” agriculture, for example?

The asteroid that wiped out the dinosaurs did more than just create a mass extinction event — it set the stage for one of nature’s most fascinating agricultural systems. While the extinction of dinosaurs is a well-known chapter in Earth’s history, what is less talked about is how that same event paved the way for ants to become farmers.

Yes, ants — specifically, a group of fungus-farming ants — began cultivating fungi after the meteor impact that sank the world into darkness. This agricultural system, which continues today, has shaped ecosystems and created complex relationships between species. In a way, it has made many modern ecosystems possible.

According to recent research published in Science, the ancestor of today’s fungus-farming ants started cultivating fungi around 66 million years ago. “The origin of fungus-farming ants was relatively well understood, but a more precise timeline for these microorganisms was lacking,” explains Dr. André Rodrigues, one of the study’s authors. This research not only narrows down the timeline but also highlights how the environmental conditions after the impact of the asteroid may have influenced the development of this unique relationship.

Indeed, life gave ants lemons, and they made margaritas!

But how did the authors reach these conclusions?

To trace the evolutionary history of fungus-farming ants, the researchers focused on analyzing ultraconserved elements (UCEs) in the genomes of 475 fungal species cultivated by ants. UCEs are regions of the genome that remain largely unchanged over long periods, allowing scientists to pinpoint evolutionary divergences (when two species split) with high accuracy.

By comparing these UCEs across fungi cultivated by ants, the researchers were able to establish when these relationships likely began and how they evolved over time.

By using this method, the researchers also created a dated evolutionary tree for both ants and fungi, helping them align the two histories. The study focused on two key fungal lineages and their relationship with the ants, bringing important insights into how this mutualism evolved and adapted to changing environments.

And what did they find?

The study’s findings suggest that the devastating asteroid impact caused mass extinctions and created an opportunity for ants and fungi to thrive together. Remember the margaritas? Well, it looks more like a margarita party now.

As darkness took over the planet and plants had a harder time fixating nutrients through photosynthesis fungi, which can feed on organic matter, spread rapidly. “It was the perfect opportunity for the ancestor of a group of ants to start cultivating these microorganisms,” says Dr. Rodrigues. With so much organic material decaying, the fungi had ample food sources, and ants were likely scavenging and feeding on these fungi as they multiplied.

Over time, this interaction became an obligatory mutualism, meaning that the ants and fungi came to rely on each other for survival. The ants would gather organic material to feed the fungi, and the fungi, in turn, provided nutrients that the ants could not easily find elsewhere.

“The pressure exerted by the meteor impact may have turned this relationship into an obligatory mutualism,” Dr. Rodrigues adds. This partnership between ants and fungi marks one of the earliest known forms of agriculture — millions of years before humans domesticated plants. Cool, right?

The ants didn’t just cultivate any fungi, though. Four distinct ant groups evolved to farm four different types of fungi. Some species, like the leafcutter ants, became particularly adept at growing a specific fungus, Leucoagaricus gongylophorus. These ants cultivate their fungal gardens by cutting leaves and using them as a substrate to grow the fungi, which they then consume. Leafcutter ants became so successful that they are now some of the dominant herbivores in the Neotropics.

Beyond being a fascinating story of survival and adaptation, this research provides valuable insights into the coevolution of species. Understanding how ants and fungi developed such a deep mutual dependence offers a window into the complexity of ecosystems and the ways in which life can adapt to dramatic environmental changes.

As the climate shifted and new habitats opened up, ants moved from wet tropical forests into more arid environments like the Cerrado savannas, further evolving their agricultural practices. Ants, like life, found a way.

Dr. Mauricio Bacci Junior, another co-author of the paper, explains that this agricultural system wasn’t just an adaptation for survival — it was a long-term strategy that shaped how ants and fungi evolved. “With more open and arid areas, there was a diversification of these agricultural insects, leading to the origin of today’s leafcutter ants,” Dr. Bacci says.

The relationship between ants and fungi also has broader implications, some that cross into the science-fiction realm.

Today, scientists study the enzymes these fungi produce for their biotechnological potential. These enzymes are incredibly efficient at breaking down organic matter and could even help in the degradation of plastics. The fungi that ants have cultivated for millions of years may help solve one of our modern-day environmental challenges.

This study highlights how life can thrive even in the face of catastrophe. The asteroid that ended the age of the dinosaurs also set in motion a unique agricultural system that has lasted for millions of years.

The mutualism between ants and fungi shows how species can coevolve, each shaping the other’s future. Today, as we face our environmental challenges, we can learn much from these deep-time partnerships about adaptation, survival, and cooperation in the natural world.

May we become ants and not cicadas!