Why thrips are thrilling: phylogenetic relationships among major groups and the evolution of the mitochondrial genome

Encompassing nearly 6,000 species, Thysanoptera has two suborders (Tubulifera and Terebrantia) with nine extant families but their phylogenetic relationships are poorly understood. We sequenced five genetic loci (18S, 28S, Histone 3, Cox I, and Tubulin alpha) for 85 species representing six of the nine extant thrips families. Trees were reconstructed using parsimony and model-based methods for the combined data set. Thrips are suspected of having a high degree of rearrangement within the mitochondrial genome, three mitochondrial genomes were sequenced using 454 pyro-sequencing for two Tubuliferan species and one Frankliniella species. The objectives of this study were to (1) test the monophyly of the suborders Tubulifera and Terebrantia; (2) elucidate relationships among the thrips families; and (3) investigate the evolution of gene rearrangements in the mitochondrial genome. Our analyses strongly support the monophyly of the suborder Tubulifera but suggest that the suborder Terebrantia is paraphyletic. Phlaeothripidae is monophyletic but the Phlaeothripinae is paraphyletic with respect to Idolothripinae. Patterns of mitochondrial genome rearrangements in light of phylogenetic relationships are discussed.