The puppeteer's grip
Deep in the humid understory of the Brazilian rainforest, a microscopic drama unfolds. A spore from the fungus Ophiocordyceps unilateralis lands on an unsuspecting carpenter ant from the Camponotini tribe. Using a combination of enzymes and mechanical pressure, the spore drills through the ant's tough exoskeleton. Once inside, fungal cells multiply and spread, feeding on the ant's non-essential tissues. For 14 to 21 days, the ant appears normal, continuing to interact and share food with its nestmates who seem unable to detect the parasite within.
The fungus doesn't invade the ant's brain directly. Instead, it forms a vast, interconnected network of fungal cells that surrounds the brain and infiltrates muscle fibers throughout the ant's body. This network then releases a cocktail of chemical compounds, including guanobutyric acid and sphingosine, to hijack the ant's central nervous system. The ant is now a puppet. It is compelled to leave the safety of its high-canopy nest and descend to the forest floor, walking erratically and suffering from convulsions that make it fall. The goal of the fungus is to maneuver the host into a location with the perfect temperature and humidity for its final act.