Highlights • Aphids have independently evolved dependence on Serratia symbiotica at least 4 times • The integration of the new co-obligate symbiont proceeds in a predictable manner • Loss of the riboflavin and peptidoglycan pathways in Buchnera leads to co-dependence • Amino acid synthesis is taken over by Serratia in a second phase of complementarity Sumx 1 McCutcheon J.P. McDonald B.R. Moran N.A. Convergent evolution of metabolic roles in bacterial co-symbionts of insects. Proc. Natl. Acad. Sci.
