SEM image of endoparasitoid
ciliates of the genus
Collinia, which can cause mass mortality in affected
krill populations
Parasitoids are parasites whose larvae develop inside another organism's body. This usually results in the death of the host, which sets them apart from 'traditional' parasites. There are twelve superfamilies of parasitic wasps which are entirely or mainly parasitoid. The largest family are the ichneumons, with over 80,000 species.