Manduca sexta and the cocoons of the associated parasitic wasp parasitoid Cotesia congregataWIKIMEDIA, 8THSTARButterflies and moths may have wasp genes in their genomes, transported via viruses that help parasitoid wasp larvae survive inside caterpillars, according to a study published today (September 17) in PLOS Genetics. Some of these genes appear to protect the host insects against other viral infections.
Parasitoid wasps lay their eggs in other insects. When the larvae hatch, the juvenile wasps consume the insect for food. One class of such wasps, braconid wasps, insert bracoviruses along with their eggs to suppress the host caterpillar’s immune response, which would otherwise attack the parasite’s eggs and destroy them. Bracoviruses belong to a group called polydnaviruses, which have been associated with parasitoid wasps for an estimated 100 million years. Now, researchers at the University of Valencia in Spain and the University of Tours in France have found that genes from a bracovirus associated with the wasp Cotesia congregate, which usually lays eggs in the caterpillars of the tobacco hornworm moth (Manduca sexta), were also present in non-host butterfly and moth—lepidopteran—species, including silkworms, beet armyworm ...
