The Last of Ants

Kelly’s Field Notes

Common Name: Parasitic Fungi aka Zombie Fungus

Kingdom: Fungi

Order: Hypocreales

Family: Cordycipitaceae, Ophiocordycipitaceae

Genus: Cordyceps, Ophiocordyceps, Beauveria

Species of Note (There are around 400 species of Cordyceps fungi, there are 26 species of Ophiocordyceps currently described):

Special note: there are tons of websites spouting the use of Cordyceps as supplements and remedies. Please consult a doctor before trying any new supplements as at best they may do nothing and at worst you may have an allergic reaction or other dangerous adverse side effects.

What Are Fungi:

Fungi are eukaryotic organisms (membrane bound organelles, can be unicellular or multicellular) that are mostly terrestrial but are found in aquatic ecosystems as well. Fungi are usually categorized into 4 groups: Chytridiomycota (chytrids), Zygomycota (bread molds), Ascomycota (yeasts and sac fungi), and the Basidiomycota (club fungi). Cordyceps are in the Ascomycota group and are called sac fungi. Ascomycota are named for their ascus which is a sexual structure containing non motile spores (though some do reproduce asexually). Some familiar Ascomycota are brewer’s yeast, bread yeast, and morels.

Life Cycle: 

Special note: Cordyceps fungi cannot currently infect humans due to our high body temperatures. We run so hot we’d denature their proteins, so now worries as you read through this!

Ophiocordyceps unilateralis  and O. pseudolloydii as examples-

Several species of ants are susceptible to this fungal infection, one paper noted 10 species in their study. Within that study ants seemed to climb plants randomly. The stroma to perithecia pad can happen multiple times on one ant corpse. We don’t really know what compels the ants to seek the underside of a leaf - speculation is either manipulation of muscle fibers and/or chemical manipulation of the brain. The fungus does not enter the ant’s brain. The fungus forms a scaffolding around the ant muscle bundles and interfere with the ant’s nervous system, controlling it at the muscles. Unlike the television show and video game, hosts are not infected through the mouth. Likely what happens is floating spores attach to the ant’s carapace and slowly penetrate their body. Additionally, Ophiocordyceps does not communicate through a wide fungal network, each infected individual is contained.

Cordyceps sinensis -

In the presence of other helpful fungal species the mummification time of the caterpillar can speed up to 3 - 5 days from 50 days. It also increases the infection rate from 3% to 60%.

Beauveria bassiana -

This fungus has been used as biological control of many agricultural pest species and mosquitoes. While considered safe for humans to come into contact with, there has been at least one case of an immunocompromised human becoming infected. It has also been known to infect captive alligators and tortoises.  

The Last of Us:

In the opener for The Last of Us we see a variety of beautiful fungi growing in a sort of Game of Thrones style opening credits. It’s important to note that the slime mold shown is not a fungus. Slime molds used to be a subkingdom of fungi but are not classified as such any longer. Slime molds now fall under Phylum Amoebozoa (that’s right, with amoebas!).

There is a scene in the show where hyphae (branching filaments of mycelium) are shown growing into “zombie” bodies and connected to each other through the ground. Cordyceps do not work like this, they are pretty localized to their hosts.We do have species of fungi that are connected via a form of  “fungal network.” They don’t really do this on their own! Fungi will use their mycelium to tap into tree roots and form vast networks where trees and fungi exchange chemical signals, water, and nutrients. Globally, it is expected that there are trillions of miles of fungal networks but locally they can extend for many miles.

The characters in the show discuss whether or not the fungus has intelligence and/or a consciousness. Intelligence and consciousness are slippery words in biology, but for the purposes of this podcast let’s talk a little about what that might mean in fungi in a general way. We know fungi respond to external stimuli. In lab studies, when hyphae are punctured or sliced the fungus will push resources to the injury to heal it. Hyphae growth rate and branching patterns shift in response to confinement. Fungi that infect humans also alter their growth forms when entering a host which protects the fungus before the human’s system can create an immunological defense. This is a type of forethought. There is a theory catching on called “cellular consciousness” that basically describes cells as “self-referential “knowing” problem-solving entities.” An important quote on this “The fungus is not thinking in the sense that a brained animal thinks, but some of the underlying cellular processes of signal transduction are bound to be homologous.” By homologous Dr. Money (2021) means thinking and the way signaling works through cellular processes are fulfilling the same purpose. Fungi will also move resources to nutrient deficient parts of their hyphae. 

If we want to discuss learning, we see that as well. Laboratory studies have shown if shocked some fungi will immediately increase their growth rate after being shocked a second time. The fungi can remember being shocked for up to 12 hours. Another fascinating study shows memory and spatial navigation in fungi. The fungal colony was given a bait wooden block next to its main colony to grow towards, but when the blocks were separated the original block still grew in the direction of where the bait block used to be. And again, while not fungi, there have been many experiments done on slime molds that have similar outcomes, including finding the shortest path to food sources.

Fungi and Humans:

Recommended Reading:

Arora, David. Mushrooms demystified. Ten Speed Press, 1986.

Arora, David. All that the rain promises and more: a hip pocket guide to western mushrooms. Ten Speed Press, 2022.

Bunyard, Britt. The Lives of Fungi: A Natural History of Our Planet's Decomposers. Princeton University Press, 2022.

Pollan, Michael. How to change your mind: What the new science of psychedelics teaches us about consciousness, dying, addiction, depression, and transcendence. Penguin, 2019.

Sheldrake, Merlin. Entangled life: How fungi make our worlds, change our minds & shape our futures. Random House Trade Paperbacks, 2021.


Fantastic Fungi with Paul Stamets on Netflix

How to Change Your Mind with Michael Pollen on Netflix


Ashworth, James. “Mind-Controlling Fungus Could Cause More Crop Damage in Warmer Climates.” Natural History Museum, 

Baluška, František, et al. “Biomolecular Basis of Cellular Consciousness via Subcellular Nanobrains.” International Journal of Molecular Sciences, vol. 22, no. 5, 1 Jan. 2021, p. 2545,

‌“Beauveria Bassiana.” Wikipedia, 21 Aug. 2021,

Harvey, Fiona. “World’s Vast Networks of Underground Fungi to Be Mapped for First Time.” The Guardian, 30 Nov. 2021,

‌“Fungus - Parasitism in Plants and Insects.” Encyclopedia Britannica,

‌Georg, Lucille K., et al. "Mycotic pulmonary disease of captive giant tortoises due to Beauvaria bassiana and Paecilomyces fumoso-roseus." Sabouraudia 2.2 (1963): 80-86.

Heyward, Giulia. “The Zombie Fungus From ‘The Last of Us’ Is Real — but Not Nearly as Deadly.” NPR, 30 Jan. 2023,

Jensen, J. M., B. E. Robinson, and G. S. Bulmer. "Fatal mycotic pulmonary disease of captive American alligators." Veterinary pathology 16.4 (1979): 428-431.

Lu, Jennifer. “How a Parasitic Fungus Turns Ants Into ‘zombies.’” Animals, 24 Jan. 2023,

Microbiology Society. “Fungi.”, 2020,

Money, Nicholas P. "Hyphal and mycelial consciousness: the concept of the fungal mind." Fungal Biology 125.4 (2021): 257-259.

‌Mongkolsamrit, S., et al. "Life cycle, host range and temporal variation of Ophiocordyceps unilateralis/Hirsutella formicarum on Formicine ants." Journal of invertebrate pathology 111.3 (2012): 217-224.

“Ophiocordyceps Sinensis - Microbewiki.”,

‌Posada, Francisco J., and Fernando E. Vega. "A new method to evaluate the biocontrol potential of single spore isolates of fungal entomopathogens." Journal of Insect Science 5.1 (2005): 37.

Vallverdú, Jordi, et al. "Slime mould: the fundamental mechanisms of biological cognition." Biosystems 165 (2018): 57-70.