The Fungus That Steers Ants
In tropical forests, ants infected by a fungus climb to a precise height, bite into a leaf and die. Then a stalk grows out of their heads.
What was reported
In tropical forests, carpenter ants infected with the fungus Ophiocordyceps unilateralis stop behaving normally. They leave the nest, wander, and climb plants to a height of about 25 centimetres above the ground, often on the north side, where the humidity and temperature are just right. There they clamp their jaws on the vein of a leaf and die.
Days later, a stalk grows from the back of the ant's head and rains spores on the forest floor, infecting more ants. Whole 'graveyards' of ants can be found in some forests. The naturalist Alfred Russel Wallace collected an infected ant in Sulawesi in 1859.
Explanations offered
Scientists have found that the fungus grows through the ant's body and muscles, controlling its movements without directly invading the brain. Ant colonies defend themselves by carrying sick ants away from the nest. The fungus inspired the video game and television series The Last of Us.
- When
- First collected in 1859
- Where
- Khao Yai National Park, Nakhon Nayok, Thailand
- Witnesses
- Alfred Russel Wallace, then biologists
- Status
- Explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
More from Thailand