Ants are sophisticated farmers—they build fungi gardens in underground chambers, weed and water their gardens, and even use antibiotics and chemicals to protect their crops from harmful bacteria. Scientists believe that fungus farming ants probably all came from the same ancestor in the rain forests of South America some 60 million years ago. The ants began farming fungus that grew on decomposing wood, which proved to be a nutritious and protein-rich food, setting off an evolutionary revolution (Johnston, 2016).
Just as agriculture was a major milestone in human life, fungus farming had a significant impact on ant life increasing the size of ant colonies. But not all ants are created equal. Biologists divide farming ants into two broad groups: “higher” and “lower” level fungus farmers. Among the “higher” group are the leaf cutter ants, who organize themselves into different complementary tasks as in a factory production line.
The higher level farming ants dig deep, underground chambers to keep their fungus dry or take their fungus to dry, desert-like climates. They control temperature and humidity by bringing water from fruit, plants, and dew. By growing in dry climates, the fungus becomes domesticated and can no longer escape the ant gardens or interbreed with wild fungi. Thus, the relationship between the ants and the fungus becomes one of co-dependency.
The sophistication of ant farmers is quite remarkable when you consider that even though they grow the same crop year after year, they maintain the health of their farms by producing chemicals to make farming sustainable. Farming single crops can lead to a buildup of pests and disease and spread rapidly putting the whole food supply chain at risk. But the ant farmers have been successful in sustainable farming.
The lower level farming ants do not domesticate their fungus and are based mostly in tropical forests, where the fungus can interbreed with wild fungi and thus has the capability of living independently. In the evolutionary revolution, these ants did not develop a symbiotic relationship with their food source and also fulfilled the hunter gatherer role.
Guarino, Ben. “How Humble Fungus-Farming Ants Turned into Agricultural Titans.” Washington Post (Washington, DC), April 11, 2017. Accessed August 5, 2017. https://www.washingtonpost.com/news/speaking-of-science/wp/2017/04/11/how-humble-fungus-farming-ants-turned-into-agricultural-titans/?utm_term=.cc9296541d5f.
Johnston, Ian. Ian Johnston to Independent newsgroup, “Ants Invented Farming 60 Million Years Ago After Ditching Hunter-Gatherer Lifestyle, Scientists Discover,” July 20, 2016. Accessed August 5, 2017. http://www.independent.co.uk/news/science/ants-invented-farming-60-million-years-hunter-gatherer-lifestyle-scientists-genes-genetics-a7146186.html.
Klein, Joanna. “How Ants Figured Out Farming Millions of Years Before Humans.” New York Times (New York, NY), April 11, 2017. Accessed August 5, 2017. https://www.nytimes.com/2017/04/11/science/ant-fungus-farmers-evolution.html.