Ants Started Farming Millions of Years Before Humans Did
Ants are remarkable creatures. They can cling together to form rafts or ant bridges. They even seem to know when they have the perfect ratio of ants-in-bridges to ants-gathering-food for maximum efficiency. When you bunch them together, ants display properties that are similar to both solids and liquids.
And now we know that they were the world's first farmers. Or, at least, they were farming long before humans were.
A new study led by the Smithsonian Institution and the University of Copenhagen found that a species of ants in South America known as attini were cultivating fungi 55 to 60 million years ago, just after the age of the dinosaurs. By analyzing the genes of today's fungus-farming ants, the scientists pieced together the history of ant farmers and the fungi species they harvested.
"Industrial-scale farming, comparable to that in humans, has evolved in only two non-human organisms, the fungus-growing ants and termites," says the study, published yesterday in the journal Nature Communications. "Social insect farmers cultivate fungi in subterranean gardens to produce edible proteins, lipids and carbohydrates through decomposition rather than the photosynthesis of most human crops. The fungus-farming attine ants in particular have become model systems for mutualistic symbiosis research."
The earliest ant farmers abandoned their hunter-gatherer existence to live in small colonies that could be sustained by fungi that grew on decomposing woody plant matter. As time passed, both the ants and the fungi evolved to improve the efficiency and benefits of the symbiotic relationship. Roughly 25 million years ago, a species of ants began cultivating specific fungi that provided protein-rich bulbs, which the ants would harvest preferentially.
As the food supplied by the fungi became more nutrient-rich, the colonies of fungus-farming ants grew in size until an entirely new species emerged about 15 million years ago. Leafcutter ants, which still exist today, started gathering plant matter not to eat, but to fertilize vast underground farms of fungi that decompose the fresh leaves ants truck in every day.
Over time, the ants and fungi continued to evolve, until the fungi stopped producing the enzymes needed to digest woody plant matter and relied entirely on the fresh greens supplied by the ants. The fungi also started producing swollen, fruiting sacs full of protein-a perfect food source for the leafcutter ants, which developed enzymes to easily digest the fungi sacs. They can no longer eat anything else. Today, the two species are entirely reliant on one another for survival, yet vast colonies with millions of fungus-farming ants thrive.
Meanwhile, we humans developed agriculture only about 10,000 years ago. Newbies.
Source: Smithsonian Tropical Research Institute/Science Daily
