Evidence from mitochondrial genomics on interordinal relationships in insects

Mitochondrial (mt) genomes are the largest molecular data source for deep level insect phylogenetics that is also obtainable in a reasonable timeframe and for a reasonable cost. Over 100 insect mt genomes have been sequenced, representing 29 of the 30 orders, multiple suborders for a third of the orders, and many representatives of the mega-diverse orders. Genome rearrangements have been found in a third of the insect orders however these rearrangements diagnose groups of ordinal or lower rank. Sequence based phylogenetic hypotheses utilizing mt genomic data are a promising source of data on interordinal relationships however these studies are hampered by base compositional biases, unequal rates of nucleotide substitution across groups and other long-branch effects. Available data from the field of insect mitogenomic phylogenetics is reviewed and future directions in this research outlined.