Parasitoid wasps are a little known, but extremely prolific group of wasps, who provide one of the best examples of evidence for evolution that I’ve come across. Parasitoid wasps have a particularly gruesome way of life. They make a living by laying their eggs inside the larvae of another insect, often a caterpillar. As the young wasp develops, it devours the host from the inside out, eventually emerging and killing the host.
Parasitoid wasps are found in 37 different families of a single order, the Hymenoptera, which contains all bees, wasps and ants. There are thousands, maybe even millions of species of parasitoid wasp, each preying on a different host, utilising a different set of tactics to subdue their victim. Many parasitoid wasps are considered to be beneficial to humans because they kill garden pests such as aphids. But this is not the important part of the story.