Phylogenomics and the evolution of hemipteroid insects

Abstract

Hemipteroid insects (Paraneoptera), with over 10% of all known insect diversity, are a major component of terrestrial and aquatic ecosystems. Previous phylogenetic analyses have not consistently resolved the relationships among major hemipteroid lineages. We provide maximum likelihood-based phylogenomic analyses of a taxonomically comprehensive dataset comprising sequences of 2,395 single-copy, protein-coding genes for 193 samples of hemipteroid insects and outgroups. These analyses yield a well-supported phylogeny for hemipteroid insects. Monophyly of each of the three hemipteroid orders (Psocodea, Thysanoptera, and Hemiptera) is strongly supported, as are most relationships among suborders and families. Thysanoptera (thrips) is strongly supported as sister to Hemiptera. However, as in a recent large-scale analysis sampling all insect orders, trees from our data matrices support Psocodea (bark lice and parasitic lice) as the sister group to the holometabolous insects (those with complete metamorphosis). In contrast, four-cluster likelihood mapping of these data does not support this result. A molecular dating analysis using 23 fossil calibration points suggests hemipteroid insects began diversifying before the Carboniferous, over 365 million years ago. We also explore implications for understanding the timing of diversification, the evolution of morphological traits, and the evolution of mitochondrial genome organization. These results provide a phylogenetic framework for future studies of the group.

Keywords: Hemiptera; Psocodea; phylogeny; systematics; transcriptomes.

Fig. 1.

Dated phylogeny of hemipteroid insects (Hemiptera, Thysanoptera, and Psocodea) based on maximum likelihood analysis of a supermatrix of first and second codon position nucleotides corresponding to 859,518 aligned amino acid positions from transcriptome or genome sequences of 193 samples. Colored circles indicate bootstrap support. Timescale in millions of years (Bottom) estimated from MCMCTree Bayesian divergence time analyses using 23 fossil calibration points and a reduced dataset. Number of species sampled from each group indicated in parentheses. Higher taxa are indicated as taxon labels and below branches; most convenient generalized common names are above branches. Images represent five major groups: Heteroptera, Auchenorrhyncha, Sternorrhyncha, Thysanoptera, and Psocodea.