Ants from a South American group farmed fungi some 55 to 60 million years ago, whereas humans began subsistence farming around 10,000 years ago, progressing to industrialised agriculture only in the past century, according to a new research.
The genes of the ant farmers and their fungal crops reveal a surprisingly ancient history of mutual adaptations, according to the study published in the journal Nature Communications. This evolutionary give-and-take has led to some species the leafcutter ants developing industrial-scale farming that surpasses human agriculture in its efficiency, it said.
The scientists found that 55 to 60 million years ago ants belonging to the tribe Attini switched from a hunter-gatherer lifestyle to subsistence farming of fungi that grew on decomposing, woody plant matter. The slow-growing fungi sustained tiny colonies of ants, but it was the first step toward agriculture on a much larger scale.
“The ants lost many genes when they committed to farming fungi,” said Jacobus Boomsma, research associate at the Smithsonian Tropical Research Institute and biology professor at the University of Copenhagen. 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 more nutritious crop.
“It led to an evolutionary cascade of changes, unmatched by any other animal lineage studied so far,” Boomsma said. 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.
By contrast, humans began subsistence farming around 10,000 years ago, progressing to industrialised agriculture only in the past century, the research said. Put in human terms, the leafcutter ants’ success is akin to people figuring out how to grow a single, all-purpose, disease-, pest- and drought-resistant superfood at an industrial scale, “by the time of the ancient Greek civilization,” Boomsma said.
Much of the research on fungus-farming ants comes from scientists working in Panama through the Smithsonian Tropical Research Institute during the past 25 years. The new study is one of the first attempts at looking at the entire genetic makeup of both the ants and the fungi, instead of just a few selected genes of interest.
Co-author Ted Schultz of the Smithsonian’s National Museum of Natural History said there was plenty more to discover. “Because our genome data from five ants and six fungi are publicly available, we hope additional researchers will study them in the years to come,” Schultz said.