Fungus Turns Tropical Carpenter Ants Into Walking Dead
An ingeniously deadly fungus hijacks the bodies of ants for food and reproduction.
It’s like something out of a horror movie. A parasitic fungus infiltrates the body of a tropical carpenter ant, feeding on it and manipulating its body. The fungus forces the dying ant to the forest understory, an environment more conducive to its growth. The invasion of this fungal body-snatcher culminates with it sprouting a spore-laden fruiting body from the dead ant’s head.
An account of this deadly assault on tropical carpenter ants (Camponotus leonardi) by a parasitic fungus (Ophiocordyceps unilateralis) is described in the May 9, 2011 issue of the open access journal BMC Ecology.
Similar incidences of fungi parasitizing insects occur in other parts of the world. This particular case of zombie ants plays out in the forests of Thailand.
It’s a pretty gruesome affair, so if you find movies like The Thing and Night of the Living Dead too scary, now’s a good time to stop reading!
The paper’s lead author, Dr. David Hughes of Penn State University, described the ant-fungus interaction in a press release.
The fungus attacks the ants on two fronts. Firstly by using the ant as a walking food source, and secondly by damaging muscle and the ant’s central nervous system, resulting in zombie walking and the death bite, which place the ant in the cool damp understory. Together these provide the perfect environment for fungal growth and reproduction. This behavior of infected ants is essentially an extended phenotype of the fungus (fungal behaviour through the ant’s body) as non-infected ants never behave in this way.
Tropical carpenter ants spend most of their time high in the forest canopy. When they venture down to the jungle understory, they follow well-defined trails. It’s during this time that ants could get infected by fungal spores that land on their outer body.
The fungus can only complete its life cycle through the ant. Spores germinate, and the fungus penetrates the ant’s body. It proceeds to infect the entire animal, affecting its central nervous system. You can tell when a carpenter ant has been infected: instead of marching purposefully down a trail, an infected worker ant walks about haphazardly, displaying erratic behavior. Sporadic convulsions set in, causing the infected ant to fall from the canopy to the moist, cool, leafy forest understory, ideal conditions for the fungus to continue its growth.
Read more of this article, by clicking: Zombie ants: When ants become walking dead
General Manager - Staff Entomologist