Brew: Zombies! Reanimated husks of the dead returned to nibble on the flesh of the living. But when we think of zombies, are we thinking of the right things? Zombies, in their original context, were creatures of folklore borne from stories told by and to African Hatians in French plantations. The idea was when a Hatian died, they would return to Lan Guinée, or more broadly, Africa, however, to discourage them from taking their own lives, they were told they wouldn't be able to return to the land of their ancestors, but be doomed to wander the plantations for the rest of eternity as prisoners in their own bodies. The fear of being trapped in one’s own body is oh too real. So real in fact, that I can say with the utmost certainty that there are zombies skulking around as we speak. They might even be lurking under your very own backyard. What if I told you that this insect is an infected zombie? Chill: Well why is it… hollow!? Brew: The only difference between it, and the movies, is that instead of craving the sweet sweet flesh of the living, um— it just wants to freak. Today’s episode concerns insects and parasites! We’ll be talking about a couple parasites, and what they do to their hosts. And, with that out of the way, Let’s get into it! When it comes to zombies, there’s no end to the stories we can tell, and each chooses to explain their affliction a different way. George Romero’s films refer to zombies as reanimated dead. Any human who died after the onset of the zombie “event” can return to snack on the flesh of the living, not just those who were bitten. This is also true in “The Walking Dead”. Left 4 Dead's Green Flu, and 28 Days Later's “Rage virus”, explains that their zombies are not reanimated dead people, but individuals infected with a virus. Within seconds of coming into contact with the pathogen, it starts forcing them to act out aggressively, and without self preservation. Resident Evil, aside from the numerous viruses created by the Umbrella Corporation, offers invertebrate parasites called Plaga as a source of zombification. It lives inside a host’s body until some unfortunate soul has the bad luck to watch it burst out to attack them with all their tentacled horror. But there are other kinds of parasites people use to explain their fictional zombie plagues. In the video game series The Last of Us, the cordyceps fungus is behind the collapse of civilization, and the ravenousness of the game’s monsters. But unfortunately for us, it’s not all fantasy. The cordyceps fungus is real, and there are other parasites out there just waiting to get their little fungal fingers all over unsuspecting victims. When it comes to real-life, it doesn’t serve a pathogen well to force its host to ignore their survival instincts and lash out indiscriminately. The vast majority of parasites are more interested in reproducing inside their hosts, and eating them, than using their hosts to eat us. Cicadas have a long development. They lie in wait underground for a whopping 13 or 17 years depending on the species, gestating until they can emerge in a flurry of wing-ed glory. Unfortunately for some of these lil’ fellas, Massospora Cicadina begins its life cycle in the same place that they do. As they grow to maturity, the spores do as well, eventually eating away at the insect’s entire abdomen including their reproductive organs replacing it with a fungal growth, but it doesn’t limit the bug’s ability to move around, and complete their life’s purpose, reproducing. Grill: Wait, wait, wait, wait, wait. if they don’t have “reproductive organs” then how do they reproduce? Brew: Well, technically, they don’t, they just try their darndest. The fungus fills its host with substances similar to psilocybin and cathinone, which amps up the cicada’s sex drive, pushing them to try to infect as many other bugs as possible and spread its spores to other cicadas in the meantime. Chill: It uses drugs to turn them into zombies? How does that work? Brew: Psilocybin is the main active ingredient in magic mushrooms, while cathinone is an amphetamine. Other substances of that caliber include opiates, and coca derivatives among others. But basically, the fungus makes the cicada high, and… ahem, randy. The cicadas attempt to mate, but since their genitals are now just big Super Mario mushrooms, they instead just pass on the fungal spores to the other innocent victims. Wahoo. Interestingly enough, male cicadas infected with Massospora perform a “wing-flick” signal that is otherwise only seen in mature female cicadas. This signal then attracts other male cicadas who attempt to mate with the infected male, spreading those spores further. This behaviour is only seen in cicadas infected with massospora as they emerged from the ground, however males who were unfortunate enough to contract it sexually do not end up behaving that way. These “stage 2” cicadas become what entomologists have dubbed “flying saltshakers of death” which, I hope you agree, is metal as all heck—pardon the language. The fungus in this stage does not modify the cicada’s behaviour, however their abdomens are still consumed, and they instead begin to let out spores as the insect flies. These spores will settle in the ground, and wait until the next generation of cicadas crawl out of their mass nurseries only to find themselves infected like their parents before them. For my fellow #gamers, you may be familiar with this next parasite. In The Last of Us, the Federal Disaster Response Agency, calls the zombie illness Cordyceps Brain Infection, which drives it’s victims to ravenously eat people before succumbing to the mushrooms, and also this!? Grill: OH GOD! What is that? Brew: It’s a bad dream, but what’s worse is that cordyceps is real! Otherwise known as Ophiocordyceps Unilateralis, this fungus is famously known for its ability to rewire ants of the species Camponotus leonardi into zombie harbingers of a fungal apocalypse. When an ant is first infected, the spores move through the bloodstream as single cells, multiplying as they go. Eventually, as their numbers increase, they begin working together to form small tubes through the ant’s body. You can see how the spores penetrate into, and permeate the spaces between muscle tissues in the ant. David Hughes, an entomologist at Pennsylvania State University, has also found that other fungal parasites which don’t take over insects minds, also form around muscle tissue, but Ophiocordyceps is unique in that the formations around an ants muscles are not simply there to sap energy from the insect. They also transmit information as well as nutrients. The cordyceps infection generates a sort of secondary nervous system around the ant’s nervous system, hijacking it for its own nefarious purposes. To Hughes' surprise, however, the cordyceps fungus commandeers the ant’s entire body—without ever touching the brain itself. Chill: That’s somehow creepier, Brew. Brew: The whole thing is Creep City, but it’s also Cool Town Junction. Grill: So it takes over your body, but leaves your brain alone? What if you can still think while it’s taking over? Ensconcing you in a prison of your own bone, and all you can do is sit there and watch as you slowly wither away into a pile of fungi and flesh? Brew: The point is that Cordyceps isn’t doing the parasitic equivalent of pushing you off your bike and riding away, it’s more like it installs a second seat and starts steering without you ever knowing that it’s there. It does this by releasing a complex combination of chemicals into the ant’s nervous system. Hughes believes that the fungus exerts more direct control over the ant’s body, essentially puppeteering the insect’s limbs. The fungus becomes the ant’s brain, while the actual brain remains imprisoned. But that’s not the end of this story. Cordyceps must do what all creatures are compelled to do. Grill: Eat! Chill: Sleep! Howard: Kill. Brew: No! Now that the spores have permeated every nook and cranny within the insect, it must find a place to reproduce! Once cordyceps has control, it will compel the ant to roam the forest floor, searching for the perfect spot to succumb to its fungal fate. The ant will climb up the stems of nearby plants to a height of around 25 centimeters (9.8in), which contains the right temperature and humidity for the fungus’s growth. As it reaches optimum heights and moisture, the ant will be compelled to bite down on the stem with its mandibles in a terrible death grapple, permanently locking the ant’s jaws in place. When the ant is in position, the real show begins, taking place over the course of three 3-month phases. The first is the “Dead Ant Phase”, which, as it suggests, kills the ant and prepares the body for the next phase. The second is the “Stroma Stage”, in which a stalk begins to grow out of the ant’s head, and the last is the “Perithecia Stage”, where a large “fruiting body” develops at the end of the stalk, releasing more spores into the air. Unfortunately for the other ants in the colony, this whole process is usually not far from where the ant was initially infected. If they’re really unlucky, it will be right above one of their trade routes, and the cordyceps fruit will quickly spread their spores to the rest of the colony. It’s fun to let our imaginations go wild and think about all the different ways that the world that we know could come to an end, and zombies really encapsulate two of our biggest fears in a really beautiful way. They take the invisible fear of contagion, and visceral fear of predation, and wrap it all in a rotten shambling package. But lucky for us, a real zombie plague is a near impossibility, and even if it were a likelihood, the actual forces that zombify creatures across this planet are a smidge less theatrical than we like to believe. It doesn’t make it any less horrifying though. Where TV and film construct terror for our entertainment, nature does so for no one but herself, and I think about that at night. Oh, if you want me to keep bringing you to Cool Town Junction, how about you, as the kids say these days, absolutely destroy that subscribe button by clicking on it with your mouse. Also, liking this video would be, again as you kids say, thicc. Hahah! Dab me bro.
