Fungi are everywhere—in our lawns and forests, in and on our bodies, and even lurking in that forgotten Tupperware container in the back of the fridge. While some fungi are harmful, the vast majority are beneficial to their environments and serve important ecological roles.
Some fungi act as parasites, infecting their hosts and sickening or even killing them. Common human ailments such as ringworm and athlete’s foot are caused by fungi. Pathogenic fungi like rusts and mildews regularly cause costly damage to important agricultural crops. Chestnut blight, Cryphonectria parasitica, was inadvertently introduced to North America from Southeast Asia at the turn of the twentieth century and in a few short decades wiped out billions of chestnut trees in the United States, nearly causing their extinction. Fungi even attack other fungi. Hypomyces lactifluorum parasitizes species of Lactarius and Russula, transforming them into the choice edible known as the lobster mushroom.
Hands down, though, the fungal parasites that infect insects have to be among the most bizarre. These fungi keep their insect hosts alive but take complete control of their actions, using them as zombie minions to spread their spores for them.