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Tips: This article involves the actual map of insects, careful observation may find its cuteness, but really scared readers should be cautious Oh ~ ~
It was early spring and March, the sting had passed, the sound of spring thunder had awakened the dormant animals, and the spring plowing season had arrived. Humans have been engaged in agriculture for about 12,000 years, and growing crops is a more stable way to obtain food than gathering and hunting.
However, as early as 50 to 60 million years ago, insects have mastered the skills of farming. Among the several types of insects that "farm" such as ants, termites and beetles, leafcutter ants can be described as the best. They achieve self-sufficiency in food resources by cultivating edible fungi. Today, the compounder will come to talk to you about the "ant farm" of leaf-cutting ants.
Harvest leafcutter ant farm
(Image source: alexanderwild.com)
We worker ants have power
As the name suggests, leafcutter ants are best known for cutting leaves using well-developed palates. Instead of eating the cut leaves directly, they bring them back to the nest as nutrients for cultivating fungi to run their own "ant farms".
Obtaining suitable plant leaves and growing fungi is not a simple task, and leafcutter ants need different species of worker ants to cooperate with each other to complete this huge project.
Busy leafcuttering ant worker ants
(Image source: sciencenews.org)
The same leaf-cutting ant has different roles and different body types
(Image source: wikimedia.org)
The first to be dispatched are swift worker ants who act as scouts, and their mission is to travel everywhere in search of plants that can be used to cultivate fungi. Once they find a suitable gathering point, the scouts will call for a large army of worker ants to come to their aid.
The first wave of reinforcements were large worker ants who could use their mouths as scissors. Large worker ants use their extremely powerful palates to cut the entire leaf into multiple small pieces for easy transport.
If a worker desires to do a good thing, he must first use it
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Not to mention, the large worker ants bite quite round
(Image source: earthlife.net)
The plant is found, the leaves are cut off, and the next step to consider is the transportation problem. Large worker ants that cut a single leaf may have good teeth but may have average foot strength, so the work of transporting leaf fragments is not done by them, but by smaller worker ants. In the documentary, we often see a huge army of leaf-cutting ants moving forward, all of which are topped with cut leaf fragments on their heads, and these guys are small and medium-sized worker ants who act as transporters.
Transporter: "The road knows the ant force!" ”
When the transporter returns to the nest, he will pass the leaf fragments to a small worker ant of another character. Small worker ants are responsible for the most complex and important subsequent processing of the process: they need to further process the leaf fragments, chew them continuously, and mix saliva to turn them into paste-like nutrients, that is, to make the medium.
In the process of making the medium, small worker ants will also responsibly "dosing" - smearing their own feces on the paste. This is because the feces contain a higher nitrogen content, and the medium after feeding may be able to grow more fungi. Once the medium is ready, the small worker ants will transplant the strains and take good care of them until they grow mature fungi that can be used. (I just don't know if the fungus grown in this way will have a taste...) ）
"You are all physical work in front of you, and this is my technical work!"
(Image source: cdn.thinglink.me)
Thanks to the cooperation between different species of workers, the leafcutter ant family has been able to cultivate fungi for generations to support itself. In this process, the complex and sophisticated internal structure of the leaf-cutting ant nest also plays a big role. There are many rooms inside the nest, like an underground palace, and the rooms are interconnected with each other. With a large number of rooms and openings, the interior of the nest can use the principle of thermal convection to exchange gases, continuously expelling carbon dioxide and incorporating fresh oxygen, ensuring that the fungal planting room can obtain an adequate oxygen supply. Moreover, smart leafcutter ants will also close the nest entrance in special circumstances such as rain and winter to prevent rainwater backflow or cold air invasion.
Huge leafcutter ant nest
(Image source: bluebird-electric.net)
Cultivating bacteria can also moisturize the four sides
Leafcutter ants have many benefits from their agricultural labor, helping to improve the environment around the nest, in addition to providing food for family members and ensuring the prosperity of the population itself.
By comparing the environment near and far away from leafcutter nests, the researchers found that the soil near the nest was more fertile, and the adjacent plant communities had better growth parameters (that is, higher plant radius, plant height, and rhizome biomass). Leafcutter ants are able to improve the surrounding soil and plants because the large amount of waste waste from their mushroom cultivation re-enters the food chain and promotes nutrient cycling.
So, how do leaf-cutting ants deal with waste residues? In general, there are two methods: one is to transport scraps of waste outside the nest through worker ants (the method is called external dumping), which is conducive to the growth of shallower roots such as herbs and small trees, and the other is to accumulate waste in a storage room deep inside the nest (the method is called international dumping), which is beneficial to large trees with deeper roots.
Leaf-cutting ant worker ants busy carrying at the mouth of the nest
Mushroom waste residue is also a treasure
(Image source: dirtyclassroom.com)
Symbiotic fungi: I can't eat it for free
In an "ant farm," leafcutter ants and fungi are not simply edible, but mutually beneficial symbiotic. In ecology, the most classic symbiotic relationship related to ants is the "ant herds": in the process of herding aphids, ants obtain the honeydew of aphids as food; while aphids obtain ant bodyguards that can drive away predators.
The same is true of the symbiotic relationship between fungi and leafcutter ants – leafcutter ants obtain a stable food source provided by symbiotic fungi while also acting as bodyguards.
However, the natural enemies that leafcutter ants have to drive away are some of the bacteria that compete with symbiotic fungi - the small worker ants mentioned above that make culture media have an additional task when caring for symbiotic fungi, that is, to pick out the spores of other wild bacteria and remove them. Moreover, leafcutter ants themselves secrete some antibody substances to inhibit the growth of harmful bacteria (this is not the weed control work of the two-legged beasts when farming!). ）。
Being a farmer and a bodyguard again, I'm exhausted!
(Image source: kqed.org)
After a long period of co-evolution with leafcutter ants, the fungus's life history has also changed. Fungi generally multiply and spread through fruiting bodies (i.e., mushrooms) and spores, with the exception of symbiotic fungi cultured by leafcutter ants. These symbiotic fungi no longer need to produce fruiting bodies and spores, as leafcutter ants have become the only medium for their reproduction and spread.
Leaf-cutting ants and symbiotic fungi "run into" each other and depend on each other, and even young queens have to take the strains from the original family with them when they divide their nests, and establish their own new families by cultivating new ant farms.
So, in the history of "ant farms" for thousands of years, is it the leafcutter ant that domesticated the symbiotic fungus, or the symbiotic fungus that domesticated the leafcutter ant?
bibliography:
[1] farji-brener, ag, werenkraut. a meta-analysis of leaf-cutting ant nest effects on soil fertility and plant performance[j]. ecological entomology, 2015,40(2):150-158.
[2] bollazzi m, roces f. to build or not to build: circulating dry air organizes collective building for climate control in the leaf-cutting ant acromyrmex ambiguus[j]. animal behaviour, 2007, 74(pt5):1349-1355.
[3] poulsen m, hughes woh, boomsma jj. differential resistance and the importance of antibiotic production in acromyrmex echinatior leaf-cutting ant castes towards the entomopathogenic fungus aspergillus nomius[j]. insectes sociaux, 2006, 53(3):349-355.
[4] mueller ug, gerardo n. fungus-farming insects: multiple origins and diverse evolutionary histories[j]. proceedings of the national academy of sciences of the united states of america, 2002, 99(24):p.15247-15249.
[5] www.smithsonianmag.com/science-nature/how-ants-became-worlds-best-fungus-farmers-180962871/
[6] www.sciencenews.org/article/insects-ants-extreme-farming-methods-offer-good-bad-lessons
Source: Science Compound