How the asteroid that killed the dinosaurs turned ants into mushroom farmers

giant asteroid crashed into Earth, causing one of the largest mass extinctions in the history of the planet. This event wiped out not only dinosaurs from the face of the Earth, but also about 70% of all types of living organisms. Paradoxically, the cataclysm gave rise to one of the earliest forms of agriculture, which is still practiced by certain species of ants. Insects began to cultivate mushrooms for food – and this symbiotic union between insects and mushrooms has lasted for tens of millions of years.

How ants became mushroom farmers

A group of scientists from the Smithsonian Institution believesthat the cultivation of mushrooms by ants began just after the fall of the asteroid that destroyed the dinosaurs (Smithsonian Institution). After the impact, the Earth's atmosphere was filled with dust and debris, which led to a sharp decrease in the amount of sunlight and the cessation of photosynthesis. This caused massive plant death, but created ideal conditions for fungi to thrive, feeding on decaying organic matter. In such an environment, fungi began to multiply quickly, and some types of ants found a way use them as a food source.

Resourceful insects not only collected mushrooms, but also began to cultivate them, creating the first “farms” in underground nests. Then a symbiotic relationship arose between the ants and the fungi: the fungi provided the ants with food, and the ants protected the fungi from other organisms and supplied plant debris for their nutrition.

Evolution of symbiosis of mushrooms and ants

Although ants took the first steps toward mushroom growing 66 million years ago, the full development of “higher agriculture” took another 40 million years. All this time, the ants continued to develop the mushroom culture, adapting it to various conditions.

One of the important stages was the spread of fungi from tropical rainforests to drier regions such as the savannas and forest-steppes of South America. In the new conditions, the mushrooms turned out to be completely dependent on the ants: they could no longer reproduce without the help of their “farmers.”

Leaf-cutter ants (genus Atta) are one of the most advanced “farmers” among insects who cultivate mushrooms for their food. They cut off pieces of leaves and bring them to their underground colonies. Plant residues are not directly consumed by ants as food – they are used as a substrate for growing mushrooms. Both the table and the house, as they say. Fungi decompose organic material and produce special nutritional structures known as Gongylidiawhich the ants then eat.

Leaf-cutter ants diligently tend their mushroom gardens. They maintain a certain humidity and temperature in the underground chambers, cleanse the mycelium of pathogens and weeds, and introduce symbiotic bacteria into the ecosystem, which help protect the mushrooms from disease. This process is one of the most sophisticated examples of symbiotic agriculture in the animal kingdom, and has been evolving for millions of years.

As I wrote above, the mushrooms that leaf-cutter ants grow cannot survive in the wild without the help of insects. In matters of reproduction and nutrition, they completely rely on “farmers”. On the other hand, ants also cannot survive without mushrooms, making this relationship an example of perfect symbiosis.

Where do insects get their mushrooms now? Such species can no longer be found in the wild, so the winged female leafcutter, setting off on a mating flight, carries away with a lump of mycelium from the mother's nest. Having laid the foundation for her own colony, she also founds a new mushroom garden.

Influence on modern science

Study The symbiosis between ants and fungi not only reveals the secrets of evolution, but also has practical significance for modern scientists. Fungi cultivated by insects produce unique enzymeswhich help them decompose organic matter. These compounds are so effective that scientists are studying them to develop new recycling methods, including the biodegradation of plastic. So ancient social insect farms could be the key to solving modern environmental problems.

Studying the genetic data of ants and fungi allows scientists to understand how symbiotic relationships have evolved over millions of years. DNA analysis showedthat more than 200 species of ants cultivate about 280 species of fungi, creating a complex and diverse ecosystem within their colonies.

Every cloud has a silver lining. The global catastrophe that wiped out the dinosaurs gave birth to one of the earliest forms of agriculture, created by ants. This symbiosis between insects and fungi was so successful that it still exists today. Modern researchers continue to study this phenomenon, hoping to uncover the secrets of the past and at the same time find solutions for the future.

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