Ants: The Farmers of the Animal World

Beverly McClenaghan
3 March 2017

Above: Two leafcutter ants hard at work (Kathy & sam, Wikimedia Commons)

When I ask you to picture a crop farmer, what do you see? Most likely, you are thinking of a person working hard in a field. Crop farming is difficult work, and there’s a lot to do. Farmers have to feed their crops and protect them from pests and disease.

Many people think that crop farming is a sophisticated activity that only humans do. But that’s not true. Ants are crop farmers too, and they have to deal with some of the same challenges as human farmers!

Did you know? Ants are just one type of fungus-farming animal. Others including termites, beetles and snails!

What do ants farm?

Humans began farming crops like wheat and barley around 10,000 years ago. But about 50 million years before that, some ant species began farming fungus. These ants and their fungal crops have been evolving together ever since. In other words, they have a symbiotic relationship. This means that they benefit from each other. Fungi form small structures packed with nutrients called gongylidia, which provide ants with a constant food source. Meanwhile, the fungus benefits from the ants’ care, protection and movement. The ants move around a lot, starting new colonies and spreading the fungus to new locations.

Protecting and caring for fungus isn’t as easy as you might think! Luckily, ants have evolved many impressive behaviours to deal with the challenges.

Did you know? Ants started farming fungus around 50 million years ago. That’s right after the dinosaurs went extinct!

How do ants farm?

Human farmers have to provide their crops with food and fertilizer. Ants do the same for their crops. Fungi feed on organic and decomposing material, which ants have to supply. Human farmers often use cow manure to fertilize their crops. Similarly, ants use their own excrement to fertilize fungus.

Take the example of leafcutter ants. First, they collect leaves and cut them into tiny pieces. Then, the ants mix these leaf pieces with their own excrement to create a nutritious mixture for the fungus.

Did you know? The practice of cultivating fungus, whether by humans or animals, is called fungiculture.

Ant farmer problems and solutions

Fungal crops are very susceptible to (likely to get affected by) pests. Ants need to work hard to keep their crops healthy. One of the most common pests is fungal weed, a species of fungus that can harm the crop fungus.

Ants have several strategies to fight pests. For example, they monitor their crops and remove any pests that they can. Ants have also formed another symbiotic relationship with a species of bacteria. It grows on the ants’ exoskeleton and produces antimicrobial chemicals that can kill fungal weed. Ants use these chemicals as a pesticide to remove fungal weed, just like human farmers who use pesticides and herbicides.

Ants have even evolved ways to prevent pests from infecting their crops in the first place. For instance, fungal-growing ants clean themselves before they enter the nest. They do this to remove debris, waste and any microbes trying to hitchhike into the nest. As ants groom themselves, they also secrete antimicrobial chemicals to help kill any harmful bacteria or viruses.

Did you know? There are over 200 ant species that farm fungus.

Long-term relationships

Like human farmers, ants grow many different species of crops. However, one ant nest will typically only have one species of fungus. In fact, many ant and fungus species have taken their relationship a step further. They’ve developed an obligate symbiosis: the fungus cannot survive without the ant, and the ant cannot survive without the fungus.

As you can see, ant and human farmers face a lot of the same challenges. After 10,000 years, humans still struggle with many of these challenges. But ants and their fungal crops have co-evolved over eons to make things run more smoothly.

Learn More!

About ants as farmers:

Were Ants the World’s First Farmers? (2016)
J. Landers, Smithsonian Magazine

Reduced biological control and enhanced chemical pest management in the evolution of fungus farming in ants (2009)
H. Fernández-Marín, J.K. Zimmerman, D.R. Nash, J.J. Boomsma & W.T. Wcislo, Proceedings of the Royal Society Biological Sciences 276

The Evolution of Agriculture in Ants (1998)
U.G. Mueller, S.A. Rehner & T.R. Schultz, Science 25
Link to abstract. Subscription required to view full text.

About snails as farmers:

Fungal farming in a snail (2003)
B.R. Silliman & S.Y Newell, Proceedings of the National Academy of Sciences of the United States of America 100

Beverly McClenaghan

I have always loved animals and nature. This led me to pursue an undergraduate degree in zoology at the University of Guelph followed by a Master’s degree at Trent University studying avian ecology and conservation. Currently, I am working for a conservation organization in St John’s, Newfoundland. I am working in policy and outreach, which is teaching me a lot about the economic, cultural, and social side of conservation as well as the biology of conservation. Outside of work, I am an avid birdwatcher, rock climber, and hiker. I love sharing my passion for nature with others!

J’ai toujours aimé les animaux et la nature. C’est ce qui m’a menée à l’obtention d’un baccalauréat en zoologie de l’Université de Guelph, puis d’une maîtrise en écologie et conservation aviaires de l’Université Trent. Je travaille actuellement pour un organisme de conservation à St John’s, Terre-Neuve-et-Labrador. Je travaille dans les domaines de la politique et de la sensibilisation, ce qui me permet d’en apprendre beaucoup sur les aspects économique, culturel, social et biologique de la conservation. Dans mon temps libre, j’aime observer les oiseaux, faire de l’escalade et partir en randonnée. J’adore partager ma passion pour la nature avec les autres!

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