Ants belonging to a South American group switched from a hunter-gatherer lifestyle to subsistence farming of fungi that grew on decomposing, woody plant matter some 55 to 60 million years ago, shortly after the dinosaurs died out, new research has found.
By contrast, humans began subsistence farming around 10,000 years ago, progressing to industrialised agriculture only in the past century.
The genes of the ant farmers and their fungal crops revealed a surprisingly ancient history of mutual adaptations, said the study published in the journal Nature Communications.
This evolutionary give-and-take led to some species — the leafcutter ants, for example — developing industrial-scale farming that surpasses human agriculture in its efficiency, the researchers said.
Much of the research on fungus-farming ants came from scientists working in Panama through the Smithsonian Tropical Research Institute, headquartered in Panama City, during the past 25 years.
The key chapters of the history of ant agriculture were written into the genes of both the insects and their crop fungi.
“The ants lost many genes when they committed to farming fungi,” said Jacobus Boomsma, Research Associate at Smithsonian Tropical Research Institute.
This tied the fate of the ants to their food — with the insects depending on the fungi for nutrients, and the fungi increasing their likelihood of survival if they produced the most nutritious crop.
“It led to an evolutionary cascade of changes, unmatched by any other animal lineage studied so far,” Boomsma, who is also a biology professor at the University of Copenhagen in Denmark.
The researchers found that leafcutter ant species cut and sow their underground farms daily with fresh, green plant matter, cultivating a fully domesticated species of fungus on an industrial scale that can sustain colonies with up to millions of ants.
Put in human terms, Boomsma said, the leafcutter ants’ success is akin to people figuring out how to grow a single, all-purpose, diseases, pest- and drought-resistant superfood at an industrial scale, “by the time of the ancient Greek civilisation.”