Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff, Lauren vogelbam here. Zombies are a horror trope for a reason. For many reasons, really, but one is that we humans tend to like the idea of being in control of our own bodies and behavior, and in stories, the walking dead are reduced to mindless doers of damage and often modernly, spreaders of whatever infectious disease has caused the dead to rise. There are many real life infections and conditions that can alter a person's behavior, all horrific in their own right, but none we know of could cause a full on George Romero's style apocalypse or the Last of Us style apocalypse. In the video games and television series The Last of Us, a brain hijacking fungus evolves from the infecting insects and other arthropods to infecting human beings. And don't worry, that's the only spoiler we're going to give here. But today, let's talk about the real life fungi that inspired the series. Cordyceps and Afia. Cordyceps are each a genus of fungi that are often parasitic to arthropods like ants, spiders, and wasps. Fungi in general grow from spores, then consume living or dead material like wood in order to grow root like structures called mycelium and fruiting bodies like mushrooms that produce more spores. But instead of in wood, Cortceps and Affia cordyceps tend to grow in arthropods that in itself is nothing very special. A fossil evidence of fungi growing in insects has been found as far back as one hundred and five million years ago, and over a thousand fungi with insect hosts are known to exist today. But these two genera of fungi can actually change an animal's behavior when they're ready to spore in order to spread those spores as far as possible. Take, for example, a species of Apia cordyceps. The parasitizes carpent durants and hijacks the ants behavior during the last days of its life. This phenomenon caught the eye of British naturalist Alfred Russell Wallace when he was in Indonesia back in eighteen fifty nine. Even a newcomer to the area could see that something was seriously wrong with some of the ants in the rainforest. After all, carbondurants are generally pretty predictable in their behavior. They work as a team, and each ant has a very specific job, like building the nest, gathering food, or caring for the queen. When an ant is infected with the fungus, the fungus grows unnoticed in the ant's body for a while, feeding on the ant until the fungal cells account for over half of the ant's body mass. All this time, the ant has been doing its usual job and living its life. One day it begins to act very differently. Breaking off from the colony. It stumbles around by itself all day and night, climbing higher and higher into the trees. Eventually, the ant clasps a leaf for stem with its strong mandibles and dies. Check in a week later, and you'll find the dead ant's body covered in a brown mat of hair like structures, with a beige stalk having erupted from a place near its head. This stalk releases millions of tiny spores that float away on the air for more ants to step on, thus beginning the whole cycle over again. That chomping onto a leaf for stem behavior by the way is how we know that this kind of behavior altering fungal parasitism is pretty ancient. Leaf scars created by an ant death grip have been found on fossils at least forty eight million years old. In all that time, carbenter ants have evolved some strategies for avoiding these fungi, at least they try their best. Many ant species groom each other in an attempt to remove spores from their friends, while others fray their nests with fungicidal poisons and seal off parts of their nests. When infections arise, a whole ant colony will relocate if necessary. But how does the fungus affect the ants behavior to the extent that it does. It's a question that's baffled generations of scientists over the years. Some have argued that the ants aren't hijacked at all, that certain protocols have evolved in response to a fungal infection, and that the individual ants wander off not because they're being influenced by the fungus, but to avoid infecting the rest of their colony. And despite the tropes about zombies and brains, a twenty seventeen study published in the Proceedings of the National Academy of Sciences found that it's possible that the ant's brain isn't involved in the whole process at all. The researchers found that as the fungus grows inside the ant's body, its cells create an interconnected network of fibers that surround the ants muscle fibers, and that it's this network that is most likely coordinating the ants movements. They did find the fungus in the insect's head, but not in its actual brain. In a press release, the lead author of the study, an entomologist by the name of David Hughes, said, we found that a high percentage of the cells in a host were fungal cells. In essence, these manipulated animals were a fungus in ants clothing. Pretty much everything except the brain had been taken over entirely by fungal cells, which led the researchers to believe that the fungus might be preserving the brain for a reason, maybe in order to help the ants survive until it can perform its final death bite. To be fair, ant's brains are pretty small, and they make up for that by having clusters of neurons throughout their bodies that help control different work, like the movement of a pair of legs or receiving signals from an antenna. So although these findings are compelling, it's still not crystal clear what's going on between these parasitic fungi and their victims. But at least it is clear that it would be extremely difficult for a fungus to start hijacking human bodies in the way that cordyceps and a few cordyceps do with arthropods, so that's one less thing to worry about. Today's episode is based on the article Meet the Zombie ant Fungus that inspired HBO's The Last of Us on how Stuffworks dot com, written by Jeslin Shields. Brain Stuff is production of iHeartRadio in partnership with how Stuffworks dot Com and is produced by Tyler Klang. Four more podcasts my Heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.

Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff, Lauren vogelbam here. Zombies are a horror trope for a reason. For many reasons, really, but one is that we humans tend to like the idea of being in control of our own bodies and behavior, and in stories, the walking dead are reduced to mindless doers of damage and often modernly, spreaders of whatever infectious disease has caused the dead to rise. There are many real life infections and conditions that can alter a person's behavior, all horrific in their own right, but none we know of could cause a full on George Romero's style apocalypse or the Last of Us style apocalypse. In the video games and television series The Last of Us, a brain hijacking fungus evolves from the infecting insects and other arthropods to infecting human beings. And don't worry, that's the only spoiler we're going to give here. But today, let's talk about the real life fungi that inspired the series. Cordyceps and Afia. Cordyceps are each a genus of fungi that are often parasitic to arthropods like ants, spiders, and wasps. Fungi in general grow from spores, then consume living or dead material like wood in order to grow root like structures called mycelium and fruiting bodies like mushrooms that produce more spores. But instead of in wood, Cortceps and Affia cordyceps tend to grow in arthropods that in itself is nothing very special. A fossil evidence of fungi growing in insects has been found as far back as one hundred and five million years ago, and over a thousand fungi with insect hosts are known to exist today. But these two genera of fungi can actually change an animal's behavior when they're ready to spore in order to spread those spores as far as possible. Take, for example, a species of Apia cordyceps. The parasitizes carpent durants and hijacks the ants behavior during the last days of its life. This phenomenon caught the eye of British naturalist Alfred Russell Wallace when he was in Indonesia back in eighteen fifty nine. Even a newcomer to the area could see that something was seriously wrong with some of the ants in the rainforest. After all, carbondurants are generally pretty predictable in their behavior. They work as a team, and each ant has a very specific job, like building the nest, gathering food, or caring for the queen. When an ant is infected with the fungus, the fungus grows unnoticed in the ant's body for a while, feeding on the ant until the fungal cells account for over half of the ant's body mass. All this time, the ant has been doing its usual job and living its life. One day it begins to act very differently. Breaking off from the colony. It stumbles around by itself all day and night, climbing higher and higher into the trees. Eventually, the ant clasps a leaf for stem with its strong mandibles and dies. Check in a week later, and you'll find the dead ant's body covered in a brown mat of hair like structures, with a beige stalk having erupted from a place near its head. This stalk releases millions of tiny spores that float away on the air for more ants to step on, thus beginning the whole cycle over again. That chomping onto a leaf for stem behavior by the way is how we know that this kind of behavior altering fungal parasitism is pretty ancient. Leaf scars created by an ant death grip have been found on fossils at least forty eight million years old. In all that time, carbenter ants have evolved some strategies for avoiding these fungi, at least they try their best. Many ant species groom each other in an attempt to remove spores from their friends, while others fray their nests with fungicidal poisons and seal off parts of their nests. When infections arise, a whole ant colony will relocate if necessary. But how does the fungus affect the ants behavior to the extent that it does. It's a question that's baffled generations of scientists over the years. Some have argued that the ants aren't hijacked at all, that certain protocols have evolved in response to a fungal infection, and that the individual ants wander off not because they're being influenced by the fungus, but to avoid infecting the rest of their colony. And despite the tropes about zombies and brains, a twenty seventeen study published in the Proceedings of the National Academy of Sciences found that it's possible that the ant's brain isn't involved in the whole process at all. The researchers found that as the fungus grows inside the ant's body, its cells create an interconnected network of fibers that surround the ants muscle fibers, and that it's this network that is most likely coordinating the ants movements. They did find the fungus in the insect's head, but not in its actual brain. In a press release, the lead author of the study, an entomologist by the name of David Hughes, said, we found that a high percentage of the cells in a host were fungal cells. In essence, these manipulated animals were a fungus in ants clothing. Pretty much everything except the brain had been taken over entirely by fungal cells, which led the researchers to believe that the fungus might be preserving the brain for a reason, maybe in order to help the ants survive until it can perform its final death bite. To be fair, ant's brains are pretty small, and they make up for that by having clusters of neurons throughout their bodies that help control different work, like the movement of a pair of legs or receiving signals from an antenna. So although these findings are compelling, it's still not crystal clear what's going on between these parasitic fungi and their victims. But at least it is clear that it would be extremely difficult for a fungus to start hijacking human bodies in the way that cordyceps and a few cordyceps do with arthropods, so that's one less thing to worry about. Today's episode is based on the article Meet the Zombie ant Fungus that inspired HBO's The Last of Us on how Stuffworks dot com, written by Jeslin Shields. Brain Stuff is production of iHeartRadio in partnership with how Stuffworks dot Com and is produced by Tyler Klang. Four more podcasts my Heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.