The characterization of a novel cypovirus in a parasitoid-host relationship

Polydnaviruses (PDVs) in parasitoid wasps are an iconic example of the curious and expansive realm of viruses that directly benefit their host species. In this case, PDVs allow such wasps to overcome the defense responses of their host organisms. In the parasitoid/host relationship between Campoletis sonorensis and Heliothis virescens we have recently discovered two variants of another virus, present in both the parasitoid wasp and its caterpillar host. We have identified this new virus as a cypovirus, and suggest that, while it appears to have little effect upon the caterpillar hosts, it may be responsible for a high mortality rate that we have observed in our parasitoid wasps, which become exposed to the virus while feeding on their hosts. The activity of the cypovirus in the PDV lifecycle provides us with a unique chance to study the complex relationship that exists between these viruses and their development as biological weapons in their primary hosts.