I was reading about reproduction in TINY egg parasitoids earlier (as you do) and it's broken my brain a bit because it's so bonkers. See THREAD⬇️. Remember that all of this action takes place in the microcosm of an insect egg (Copidosoma floridanum📷Scott Justis) 
The female wasp lays a SINGLE egg in the host (certain moths). The egg divides again and again to form an undifferentiated mass - the polymorula. This photo shows the sequence of development from egg to polymorula to larvae (Segoli et al 2009)
The polymorula splits into discrete clusters of cells, each of which becomes a larva. Most of these clones become normal larvae, but a small proportion become SOLDIERS.
The soldiers are long, thin and anatomically simple but are armed with big jaws. Photo showing soldiers and normal larvae of twp species (L - Donnell et al 2004; R - Cruz 1981).
The soldiers search the host to eliminate competitors, i.e. the larvae of other parasitoids and even other clones of the same species. Here are some soldier larva tucking into the larva of other parasitoid wasps (L: Cruz 2981, R Uka 2013).
These soldiers will never give rise to new wasps. They do their job and then die, before the normal larvae really get stuck into the host's tissues.
The normal larvae gorge, pupate and escape the remains of their host to continue the merry-go-round. This is polyembryony at its most extreme. In some species, a single egg can give rise to 3,000 wasp embryos.
The fate of each cluster of polygerm cells depends on whether they have a germ cells or not. Those with germ cells become normal larvae and eventually wasps. Those without become dead-end soldiers whose sole task is to rid the habitat of competitors.
This photo shows the inheritance of these germ cells in the polymorula of one species
The wildly different soldier and normal larvae all come from the same genetic material. Not only that, but soldier production is increased in the presence of competitor parasitoids.
This whole thing blows my mind. So few of these animals have been studied. Just imagine what else there is to discover.
