Endogenous viruses of parasitic wasps: variations on a common theme

In a remarkable example of convergent evolution, several parasitic wasp lineages have independently captured and maintained complex DNA virus machineries, used to transfer virulence factors. Parasitic wasps, which develop inside the larvae of their insect hosts, may inject Polydnaviruses (PDVs) or Virus-Like particles (VLPs), derived from the recurrent endogenization of several large DNA viruses. PDVs evolved from the domestication in braconid and ichneumonid wasps of viruses from different families and function as gene transfer agents. In contrast, the independent domestication of nudiviruses led to the evolution of both PDV and VLP strategies. In Venturia canescens, the endogenous nudivirus has lost the ability to encapsidate DNA, instead VLPs cargo virulence molecules of wasp origin to the parasitized host.