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The Amazon Rainforest series-part 4: The diligent population checker: The killer fungus

Hi everyone,

Today we have a very special post for you. This is our very first guest blogging post. Casandra Chikanele has written an amazing post about the Amazon rainforest. This post is therefore the 4th part in the Amazon rainforest series. Enjoy!
Your Green World TeamšŸ’š



The Amazon rainforest is a diverse and wildlife intense site. Home to thousands of species of animals, insects, reptiles, and all living forms including plants and microbial entities. 1/3 of all species live in this cradle of life. About 2.5 million species of ants, one thousand three hundred species of birds, four hundred and thirty species of mammals, and many more.
This environment houses quite a numerous amount of living things, predators and prey, families, and bachelors. A place with such a diverse ecosystem, where new offspring is constantly brought forth. Some species reproduce in little numbers, while others reproduce in hundreds or thousands every few weeks. It is easy to think the forest can become overpopulated just like the human section.


The reproductive cycle of all animals differs, most animals give birth in small numbers and less frequently than some. The insect world is more generous in its reproduction, with them laying hundreds of eggs at a time, especially with ants where there are about 8 million ants per hectare in the Amazon rainforest. These insects invade every avenue of the forest from the tree tops to the forest floor and even underground.

In their numerous sizes, they work hard to keep their already mighty colony and precious monarch safe. In their large numbers, they search for food, stripping an entire section of a tress half bare if not the entirety by the time they are done. Ants consume more vegetation than any other creature in the forest. And protecting whatever they claim as theirs with all force. As it has been recorded that ants attack way larger insects in large numbers by overwhelming and even killing them.

The insects are the most successful kingdom in the Amazon rainforest, with their numbers booming, it is quite easy to think they can take over the forest, swarming all over, getting an upper hand in the ecosystem, and threatening other species.


But why hasn’t this happened.?

So typical of nature to have everything in check. Nature has numerous techniques and technologies put in place to ensure orderliness and balance, trees, forests, mangroves, moorlands, oceans, and clouds. All these are more than just beautiful landscapes. They are in fact nature's technology to ensure the balance is kept; their beauty is just a physical image, and they are much more than that. This is why the chaos of climate change is happening due to humans' involvement in tampering with nature's technology.

As nature has it, no one species can have an upper hand in the forest, not even these fast-growing, hardworking insect colonies. The more numerous the insects are, the larger the colonies grow, and the more likely they will cease to exist. This is made possible by an insect infecting parasitic fungi called cordyceps.


Now generally ants are familiar with fungi, they in fact fetch leaves that they use to cultivate their fungi farm, which they feed to their larvae; they also have antibiotic saliva that they use to keep their farm infection free.
The ants who are social animals have put in place social immunity, which is a set of procedures they use to prevent any disease from the colony. They groom each other with their antibiotic saliva, any individuals that show signs of illness are taken far away from the colony and sometimes killed to avoid infecting others, and dead ants are removed immediately before any damage ensues. Even in their little fungi farm, the ants that tend to the fungi, after cleaning up the farm and removing garbage do not come in contact with the queen or the fungus to avoid any infection harming the colony. This strict social immunity is what keeps the ants' infection free.

But the cordyceps manipulates its way around this ant’s security. How?

The cordyceps is a parasitic fungus that infects insects. It infects them, takes control of their body and mind, and manipulates them. And before the ant dies, the fungi manipulate the infected ant to climb high up a tree, about 25 centimeters above the ground and then cause the ant to grip tightly using its mandible against a stem, this is known as the death grip. And a couple of hours later the ant dies.

But how does this favor the cordyceps fungus?

The fungus causes the ants to go 25cm above the ground when the sun is highest and they grip the underside of the leaf. This height and time provide the optimal temperature and humidity for the fungus to erupt and disperse. Gripping the underside of the leaf will protect the fungi from rain and UV rays; until when night time comes and the spores can disperse when the temperature is cooler.

Why do the fungi not just manipulate the ant to move into the colony and die there and easily disperse its spores?

Well, any ant found sick, misbehaving, or infected will be killed or/and taken far away from the colony where it cannot infect others,


so causing the ant to move out on its own, will better its chances of infecting the colony. The ant moves away from the colony but not too far, just a few meters so that the colony is still within reach, and at a height that can increase far dispersion. So that when the spores are finally released, they can reach the colony and attach to a new host.
And for some other insects, it causes them to become more energetic and to find a mate quickly to ensure dispersion.

This fungus is believed to have been around for thousands of years and to have adapted to conditions and even changed its prey over time. In tropical forests where they are few leaves to grip on, the fungi have been observed to cause their victims to grip on twigs and bark.
The presence of these fungi ensures that no one species dominates, as it infects largely populated colonies of ants, beetles, praying mantis, grasshoppers, and other insects. The balance of the ecosystem is restored.


The Amazon has numerous activities and secrets that unfold within it. And new species are found as the sun spotlights them every setting day.


Casandra Chikanele is a freelance writer whose niche is wildlife and the environment. She is also passionate about nature. For more info, click here.


Sources:


Images:
Collage: This image, owned by Robyn Jay (on flickr.com), is licensed under CC BY-NC-SA 2.0.
A large gathering of ants: This image, owned by Ingrid V Taylar (on flickr.com), is licensed under CC BY-NC 2.0
Ant infected by cordyceps fungus: This image, owned by Bernard DUPONT (on flickr.com), is licensed under CC BY-NC-SA 2.0
Ants fighting: This image, owned by Matt Francey (on flickr.com), is licensed under CC BY-NC 2.0.
Sunlight on water: This image is owned by Arnie Chou on pexels.com.

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