Parasite of the month

Bracoviruses

These polydna viruses replicate in parasitic wasps that infect lepidopterans. Viral replication takes place in the ovaries of the wasp in calyx cells, allowing the vertical transmission of the virus. As such, female wasps are responsible for viral transmission but the virus is also found in male wasps.

Bracoviruses are not known to cause diseases in wasps. Instead, the virus facilitates infection of caterpillars by wasp eggs. When female wasps lay their eggs inside caterpillars, a quantity of virus is injected as well and prevents the immune system of the caterpillar from killing wasp eggs.

In a recent study, Gasmi et al. (2015 PLoS Genetics) found recurrent insertions of bracovirus DNA into lepidopteran genomes. This indicates not only that the virus can enter the germlin cells of the caterpillar by using parasitic wasps as vectors but also that this third-party might play an important role in the coevolution of braconid parasitic wasps and their hosts.

source for picture: https://burkelab.files.wordpress.com/2014/01/lifecycle2.png?w=625