Yes, zombie ants are real, and a parasitic fungus infects ants, primarily carpenter ants, hijacking their bodies and altering their behavior to spread its own spores. A fungal spore lands on a foraging ant’s outer skeleton and drills inside using enzymes and pressure. The fungus feeds on the ant’s soft tissues and multiplies throughout the ant’s body.
The fungus forces the ant to leave its colony, climb up a plant stem or twig, and bite down hard onto a leaf vein with its jaws. The locked position kills the ant. Then, a long stalk sprouts from the back of the dead ant’s head, releasing new spores onto the forest floor below to infect other passing ants.
How Does the Fungus Control the Ant?
Rather than directly controlling the brain, the fungus secretes chemicals and neuromodulatory agents that disrupt the ant’s normal nervous system and communication signals.
Fungal cells grow inside the muscles, effectively turning the living ant into a puppet before they cause jaw lockjaw (mandible atrophy). The fungus drives the ant to seek specific heights, humidity levels (often 94–95%), and temperatures that are ideal for the fungus to grow and release spores.
Healthy ants try to spot infected colony members early, grooming away spores or carrying sick ants far away from the nest. Fungal hyperparasites (other fungi that attack the zombie fungus) and specific weather needs stop the infection from wiping out entire species.
What Makes the Ant Change Its Behavior?
Researchers have discovered that the fungus seems to act on the ant’s muscles directly rather than through the brain. When researchers set out to investigate the spread of Ophiocordyceps unilateralis (O. unilateralis) throughout an infected ant, they found fungus in every part of the ant’s body except for the brain.
The fungus grew around the brain but seemed to be careful not to obliterate the ant’s central control system. Researchers have discovered that the fungus releases a variety of chemical compounds, but exactly how these work to manipulate behavior remains a topic for further investigation.
And if all that isn’t weird enough, this parasitic fungus also has its own parasitic fungi that infest it. Hyperparasites are parasites that target other parasites as their hosts. For the ants, is the enemy of my enemy my friend? That might be a matter of perspective.
Researchers theorize that these hyperparasites prevent O. unilateralis from being too lethal to the ants it infects. As an obligate parasite (meaning a parasite that needs a very specific host in order to survive), if O. unilateralis burns through its hosts too quickly, it will run out of hosts and die out. Therefore, researchers believe that these hyperparasites help to regulate O. unilateralis, allowing it to persist as a constant thorn in the side of ant-kind.
Can It Infect Humans?
No. This fungus cannot infect humans or other mammals because our higher body temperatures kill the organism instantly. Mammalian biology differs greatly from that of insects, and the human body remains too warm for most fungi. This is not to say that humans don’t get fungal infections; we do. But the number of fungi that can affect humans remains very small compared to the number of fungi in existence.
Content for this question contributed by Michelle Beaudry, resident of Warren, Worcester County, Massachusetts, USA
