As a result of this unusual biology, these particles were described as symbiotic viruses belonging to new viral family, Polydnaviridae [10] [11] [12] Since the 1970's, it was assumed that the DNA in the polydnavirus particles, as with all other viruses, encoded typical enzymes and proteins for viral replication and virion assembly and structure. However, several recent genomic studies have shown that only a small number of the genes vectored into lepidopteran hosts, less than 2%, have homologs in other viruses. Most viral DNA is noncoding, except that which codes for wasp proteins involved in suppression of immune pathways, such as phenoloxidase activation and the toll pathways [8, 13, 14] . Even before these genomic studies, it was suggested that these particles were more similar to organelles than viruses [15] . The similarities between particle structure and virions of known types of complex DNA insect viruses are striking, and suggest these immunosuppressive particles originated by symbiogenesis between viruses and endoparasitic wasps, the same evolutionary process by which mitochondria and plastids originated from symbiotic bacteria [16] . For example, most braconid wasps produce enveloped bacilliform particles classified as bracoviruses, and these resemble baculovirus and nudivirus virions [10, 15] . Similarly, ichneumonid wasps produce enveloped spindle-shaped particles classified as ichnoviruses that resemble virions of ascoviruses, viruses lethal to lepidopterans, which, interestingly, are vectored by endoparasitic wasps [15] . It must also be noted that ichnoviruses resemble other true virus particles that are structurally very similar to virions of ascoviruses, but which remain unclassified because the lack of information about their genomes [17] [18] [19] [20] [21] . However, ascoviruses and ichnoviruses display very different genome properties; similar genomic differences occur between bracoviruses and baculoviruses or nudiviruses, suggesting that convergent evolution led to the origin the different polydnavirus types from at least two different types of viruses.