The practice of agriculture has been around for millions of years, even before humans began farming crops thousands of years ago. According to a recent study, colonies of ants started farming fungi approximately 66 million years ago when an asteroid hit Earth, creating favorable conditions for fungi to flourish. This partnership between ants and fungi became more tightly interconnected 27 million years ago and has persisted until today. Scientists at the Smithsonian’s National Museum of Natural History analyzed genetic data from hundreds of species of fungi and ants to create an evolutionary timeline of ant agriculture and determine when ants first began cultivating fungi.
There are nearly 250 species of ants in the Americas and Caribbean that engage in farming fungi, with leafcutter ants being one of the most advanced agricultural systems. These ants harvest fresh vegetation to feed their fungi, which produce food for the ants. This complex relationship allows leafcutter ant colonies to thrive and can grow to millions in number. Ted Schultz, the museum’s curator of ants, has spent over three decades studying the evolutionary bond between ants and fungi, traveling to various locations in Central and South America to observe this interaction firsthand and collecting genetic samples to analyze in his lab.
By sequencing genetic data from over 475 species of fungi and 276 species of ants, researchers were able to construct evolutionary trees for both groups. Through this analysis, they determined that ants have been intertwined with fungi for approximately 66 million years, coinciding with the asteroid impact that led to a mass extinction event. While this event was catastrophic for many species, it provided an opportunity for fungi to thrive, benefiting ants that relied on them for food. The study also revealed that it took nearly 40 million years for ants to develop higher agriculture, a more advanced cultivation strategy.
The researchers traced the origin of higher agriculture back to around 27 million years ago when a cooling climate transformed landscapes globally, leading ants to take fungi into drier habitats. In these arid conditions, isolated fungi became dependent on ants for survival, paving the way for the higher agriculture system seen in leafcutter ants today. Similar to humans domesticating crops, ants cultivated fungi in a process that took millions of years to develop. The study included contributions from multiple coauthors and institutions and was supported by various research foundations and organizations, underscoring the collaborative effort involved in uncovering the evolutionary history of ant agriculture.
Overall, the research sheds light on the long-standing partnership between ants and fungi, dating back millions of years. By studying this evolutionary relationship, scientists can gain insights into agricultural strategies that have been successful for ants over time. Understanding how ants have cultivated fungi for food can offer valuable lessons for humans in agriculture and potentially inspire new approaches to sustainable farming practices. Through genetic analysis and evolutionary reconstructions, the study provides a comprehensive view of the complex interactions between ants and fungi and highlights the endurance of this mutualistic relationship over millions of years.