Naturally Occurring GMO's?

Some bugs are quite cruel to each other. A great example of this type of bug would be a parasitic wasp. Many species of parasitic wasps will lay their eggs into a living host and have the host be eaten alive by the larvae. To keep the host alive, the wasps will also inject viruses that keep the butterfly from acting erotic/harming themselves which could potentially kill the larvae. Some viruses even cause them to go and die at certain locations which would be advantageous in hiding wasp larvae until maturation.

Now why the heck would this pertain to genetics? Well, these viruses (bracoviruses) being injected by the wasps are actually causing naturally occurring genetically modified butterflies. Since the viral DNA integrates with the host cell DNA, it becomes a permanent part of their genome. When the host is not killed by the larvae, or when the wrong host is injected with the virus, the next generation of butterflies has the possibility of containing this gene, which through domestication, has been seen to be advantageous for butterflies by protecting them from other pathogenic viruses.