Fig. 1: Cotesia species life cycle, phylogeny, and gene content.

A Major traits involved in the parasitoid koinobiont lifestyle and genome content of six Cotesia species. First (1) OLFACTION plays an important role in the detection of the plant (tobacco) attacked by caterpillars and host (M. sexta) larvae acceptance by adult wasps (C. congregata). Once the host is accepted, the wasp injects its eggs bathed in ovarian fluid filled with bracovirus particles (2). Bracovirus particles infect host cells, from which expression of bracovirus virulence genes (3) alter host immune defenses, allowing wasp larvae development (the eggs laid in the host body would otherwise be engulfed in a cellular sheath of hemocytes). As the host ingests plant toxic compounds, such as nicotine, while feeding, wasp larvae consuming the hemolymph containing these compounds rely on (4) detoxification to complete their life cycle. However, in these species associated with endogenous viruses the most important trait for parasitism success consists in (5) bracovirus morphogenesis during wasp metamorphosis, using genes originating from a nudivirus ancestrally integrated in the wasp genome. As massive production of virus particles occurs within wasp ovaries, (6) wasp immunity may be induced during particles production; d2, d3, d4, d5 refer to developmental stages of C. congregata larvae³⁶. B Pictures of the six Cotesia species sequenced (credit H. M. Smid and R. Copeland). C Phylogeny of these species based on 1058 single-copy orthologous insect genes including the Microgastrinae Microplitis demolitor and outgroups (N. vitripennis, A. mellifera, and D. melanogaster). Black dots highlight branches with at least 90% support from maximum-likelihood analysis (1000 bootstraps). D Distribution of shared genes at several phylogenetic levels. Full protein-coding gene sets were included to identify orthologous gene groups. The “shared by some” category refers to genes shared by at least nine species among the ten studied. Note that the lower number of genes for C. congregata probably reflects the higher quality of the genome assembly obtained.