As human beings we take pride in our ability to think, imagine, and reason. As such, we often place ourselves at the zenith of Aristotle’s scala naturae. Why would we be anywhere but at the top of the animal hierarchy? After all we made the scale and claimed the top as our rightful place. What if ants had a say on where they fell on the hierarchical scale? Leafcutter ants in particular would have much evidence in their favor for why they are one of the largest and most complex animal societies on Earth.
Humans have been farming for about ten thousand years, but they do not hold a candle to the 50 million years of the leafcutter ants farming their fungus gardens! Leaf cutter ants make their living by cutting and transporting leaf fragments to their nest. The leaf material in the nest is then fragmented, chewed up, and the pulp is used as a nutrient source to grow fungi. The fungi utilize enzymes, which are able to break down the toxins in the leaves into sugars and proteins that are safe for the ant to consume. This is part of a symbiotic relationship the ants and fungi have.
The nest of leafcutter ants can attain great size. Researchers performed an excavation of a leafcutter ant nest and estimated that the ants had moved over forty thousand kilograms of soil. Within the same nest the ants had stored nearly six thousand kilograms of leaf matter. Nests such as these can have over one thousand entrance holes and two thousand chambers.
Leafcutter ants are considered a eusocial society, which means that there is a division of labor between the reproductive and non-reproductive members. A single fertile queen is present to produce offspring and sustain the society. They have a full caste system that includes the minims, minors, media, and majors each with a very specific job to do. These members fulfill all of the roles necessary to maintain their society. Medium sized ants forage and transport leaf fragments. Large ants act as soldiers to protect foragers from ground attacks. Other leafcutter ants perform tasks such as processing leaves, tending to larvae, maintaining the fungal gardens, and even a specialized group that performs waste management.
Leafcutter ants make up for their small size with large numbers. They are important consumers in tropical ecosystems because of their ability to move large quantities of soil and process large amounts of leaf material in their nests. Leafcutter ants are the dominant herbivores of the New World tropics. About 12-17 percent of all leaf production in the tropical forest is cut by these ants.
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