Phylogenomics of the quadraceps-complex of lice (Psocodea: Phthiraptera) and its bacterial endosymbiont diversity

Phylogenies help reveal evolutionary patterns and relationships of organisms. With parasites, they can also reveal coevolutionary relationships including cospeciation events or host switching. Parasitic lice (Psocodea: Phthiraptera) are an ideal study system for examining these patterns because many lice are host specific, or specific to only a few related host species. The Quadraceps-complex of lice (Ischnocera) consume feathers and parasitize birds in the orders Charadriiformes, Coraciiformes, Gruiformes, and Pelecaniformes. We constructed a phylogeny of these lice using whole genomes from Illumina shotgun sequencing. This phylogeny was compared to their avian hosts for insights into patterns of speciation, revealing extensive codivergence in some lineages and host-switching in others. In addition, lice and other insects with nutritionally limited diets often have bacterial endosymbiont communities that supplement their diets. There have been several genera of bacteria found in lice including Sodalis and Wolbachia, a bacterium of diverse life histories across its hosts. We examined the endosymbiont community of the Quadraceps-complex lice using de novo assembly methods and have mapped the diversity of this community onto the louse phylogeny finding evidence of Sodalis and Wolbachia in different species of these parasites.