Genomics of intracellular symbionts in insects

Endosymbiotic bacteria play a vital role in the evolution of many insect species. For instance, endosymbionts have evolved metabolically to complement their host's natural diet, thereby enabling them to explore new habitats. In this paper, we will review and give some examples of the nature of the metabolic coupling of different primary and secondary endosymbionts that have evolved in hosts with different nutritional diets (i.e., phloem, xylem, blood, omnivores, and grain). Particular emphasis is given to the evolutionary functional convergence of phylogenetically distant endosymbionts, which are evolving in hosts with similar diets.