Ants are an amazing species of insect, from the way they work in unison, the way they are all willing to sacrifice their lives for their queen, and the way they have perfectly adapted to almost any kind of surroundings. And while some people even have trouble when trying to keep a simple cactus alive, ants have perfected farming. What is more amazing is that they did this in the desert some 30 million years ago. Humans were not even present on the planet when ants domesticated their first fungus.
For example, leafcutter ants do not eat the leaves they chop up, even though their name might suggest otherwise. The leaves they chop up are used as harvesting material for their tiny fungi farms. These fungi are later on used as one of the ant’s main food sources. But this is not something that ants have begun doing recently. In fact, scientists think this behavior has been developed anywhere from 30 all the way up to 65 million years ago. A team of scientists, during a study in 2016, discovered that during their evolution, some ant colonies farmed fungi and they then became dependent on one another in order to survive. In a study performed in 2017, a team of scientists led by entomologist Ted Schultz discovered just when and how all this came to be.
When observing different ant colonies, the scientists noticed a clear difference in the dependency of some fungi on their respective colonies. So-called lower fungi can survive on their own, even when their colony leaves them behind or they somehow escape. The higher form of fungi is more dependent on their colonies. This makes little sense when observed from the outside, but from the perspective of the ant colonies, this makes perfect sense. This all harkens back to the way in which different colonies feed and cultivate their fungi crops. Some of the fungi that the attine ants cultivate do not produce spores. Spores are used for spreading fungi seed. Also, leafcutter ants feed plants with fresh leaves, but other types of ants feed them with dead biomass. The result is the same, as both colonies produce a luscious farm right there in their colony.
So, the spores were the main focus of the scientist’s study. In wet conditions, fungi spread more easily, so the ants living in rainforests or other similar biomes have an easier time cultivating and producing their fungi crops. In these circumstances, fungi can and do spread on their own. So, scientists came to the conclusion that the great leap in ant farming must have occurred in a warm but dry climate. Something similar to today’s savannahs and deserts. The fungi colonies produced in these conditions had to be kept underground and from there, their spores were unable to spread further. Any moisture that was produced in the desert was done so underground. Over time, the fungi lost their ability to survive outside in the desert. But in at the same time, ants lost their ability to produce an asparagine. Asparagine is a key amino acid which they now received only from the fungi. Even as the ants moved into moist environments like rainforests, the mutual dependency between them and fungi remained.
This all occurred during a period when Earth began to cool down, and drier climates became more prevalent. This was still a long time before humans even thought about any form of serious agriculture. One thing in which we surpass the ants is understanding the processes we changed. Wheat, for example, lost its ability to produce bursting seed pods and depends solely on humans to spread its seed.