Halloween Story

A symbiotic organism lives in our body, it has a neural network in our gut, and has 10x more cells than we do … in our “own” body. We call it/them bacteria. They are our ancestors, for 3 billion years. They are intimately tied to much of our well-being: physical aspects of digestion, inflammation, immunity and psychological moods, motivations and depression. To name a few. It’s a little creepy, don’t you think? It’s like those parasitic cordyceps. But ours are for the good, right? And that’s my Halloween story for October. Just wanted to get a jump on it.

Zombie-ant parasitic fungus castrated by hyperparasitic fungus

Ant colonies are protected against brain-manipulating parasitic fungi by another fungus

A dead zombie ant infested with the parasitic fungus Cordyceps. Photograph: David Hughes/Penn State University

The modus operandi of the Cordyceps fungi is the stuff of nightmares. These parasites grow inside their insect hosts by feeding off the non-vital organs, and manipulate the hosts’ behaviour so that they can reproduce. When it is ready to produce spores, the fungus grows into the brain and releases chemicals that make the host climb a plant then attach itself near the top. It then kills its host by devouring its brain, before sprouting a mushroom from the top of its head, which disperses its spores as widely as possible.

Zombie Ants