Ants and Agriculture: Did the First Farmers Have Feelers?

by Marianna Sorensen

Spring 2017 Intern

When I see ants running around my yard, I’m usually not impressed. Those little guys seem so vulnerable and can get trampled on so easily. Then again, that was before I knew that several ant species began farming long before humans ever did.

Small, black ants, called Philidris nagasau have their own form of farming and have been doing it for around 3 million years. These ants gather the seeds of their favorite food, Squamellaria, which is a lumpy, brown plant. They then put the seeds in crevices of tree bark and fertilize them with their own waste. Once the plants have grown, the ants harvest the seeds and plant them again. This way, the cycle continues and both Philidris nagasau and Squamellaria are happy.

Leaf-cutter ants also farm, but they work with fungi instead of seeds. And they are not limited to places where fungus grows. When a colony gets too big, the queen ant leaves with a fungus that can be grown when she starts a new colony. These ants have been doing this for at least 8 million years.

A third species, Acropyga, don’t farm plants, but other bugs called mealybugs—kind of like the way humans care for bees, so we can eat their honey. The Acropyga carry the mealybugs around and ingest a liquid the mealybugs secrete called honeydew (no, it’s not the melon). Acropyga, like the leaf-cutter ants, bring their “crop” with them when they start a new colony. A queen actually carries a pregnant mealybug to her new colony and then this mealybug starts a new generation for the Acropyga to raise. Acropyga have maintained this system with the mealybugs for quite a while—15 to 20 million-year-old evidence of this farming in action has been found in an amber fossil of Acropyga holding mealybugs.

Compared to these ants, humans began to farm what seems recently. Humans started harvesting things in the Stone Age at least 12,000 years ago in what is now Iran. There, archaeologists have found stone tools as well as grains and seeds. They turned out to be different kinds of lentils, barley and peas—like those we eat today. After studying these, archaeologists can tell that, at first, humans just picked the food they found. However, about 10,000 years ago humans started selecting plants with a certain attribute they liked. An example of this early domestication in present-day Iran is corn that had tough ears, which humans kept selecting over time because it was easier to harvest.

A claim to agricultural fame can only (as far as we now know, at least) be made by four animal groups: humans, bark beetles, termites and ants. Though I’m proud that we are one of those four, I never thought that we had so much in common with those bugs!

Did You Know?
There are more than 10,000 species of ants. Instead of farming, one species in the Amazon sets traps. Allomerus decemarticulatus make traps from plant fibers, and when a bug gets stuck on one, the Allomerus decemarticulatus are waiting beneath.