Ophiocordyceps unilateralis - or the ant parasitic fungus

Ophiocordyceps unilateralis is a pathogenic fungus from a group of around 400 known species of Cordyceps. Most species target a particular host, in our example the ant.

The spores infect the ant and before killing the ant changes its behaviour. This change makes the ant climb to a high position to enable the fungus to have the ideal conditions to fruit and ensure that the spores from the fruiting body are distributed well. When the ant has reached this position the fungus kills the ant and over a period of time the fruiting body will sprout from the back of its head, while the mycelia of the fungus will replace the inside tissue of the ant leaving an exo-skeleton.

The clip from the BBCs Planet Earth, narrated by the wonderful David Attenborough, shows that when unaffected members of the colony find ants infected by the Cordyceps they take them some distance away from the colony. This is presumably to try to ensure that the colony is safe from infection when the Cordyceps eventually releases spores from the ant.

Anyway, enjoy!