Consensus in cockroach and termite phylogeny illuminates the origins of sociality
Cockroaches and termites (Blattodea) occur in almost all terrestrial ecosystems and include important decomposers, pests, as well as groups of medical importance. However, the evolution and systematics of Blattodea have long remained unresolved and recent phylogenomic studies have recovered divergent results that conflict significantly among each other and with morphology-based phylogenies. Using methods designed to counter common sources of error in genome scale phylogenetic estimation, we re-analyze the deep phylogeny of Blattodea using the largest datasets assembled to date including published transcriptomes, mitochondrial genomes, as well as data derived from Sanger-sequencing. All three datasets recovered a congruent, well-resolved and strongly supported phylogeny of Blattodea with a monophyletic Solumblattodea, and with Nocticolidae + Corydiidae comprising the earliest branching clade. The enigmatic families Lamproblattidae + Anaplectidae comprise a sister clade to Cryptocercidae + Isoptera, a novel result shedding light on the evolution of eusociality in termites. We propose the name Lanablattae for the clade Lamproblattidae + Anaplectidae and Artioblattodea for Xylophagodea + Lanablattae. Ancestral state reconstruction suggests that the ancestors of Artioblattodea was not monogamous, implying that kin selection may only play a major role in the later stages of the evolution of eusociality, while non-nepotistic cooperation may be relatively more important at the onset of social group forming. Our results provide a robust backbone phylogeny of cockroaches and termites, opening new possibilities for studying macroevolutionary patterns in this biodiverse order.