What on Earth? June 20th
Today’s answer is ‘dark vegetable caterpillar’ (Drechmeria gunnii Syn. Cordyceps gunnii).
Where is the caterpillar? Underground with a fungus growing out of its head!
Drechmeria gunnii is a pathogenic fungus. Underground the mycelium of the fungus invades a moth larva, usually of the order Hepialidae, and eventually kills it. The dark fruiting body (the thing you see in the photograph) rises above the surface to release spores.
Entomopathogenic fungi are microorganisms that infect and usually kill insects and other arthropods. Some are used as alternatives to toxic chemicals as a way to control certain pest insects. The control of plague locusts in Australia is an example.