Evolutionary Dynamics of the Mitochondrial Genome in the Evaniomorpha (Hymenoptera)—A Group with an Intermediate Rate of Gene Rearrangement

We determined the complete mitochondrial (mt) genomes of three evaniomorph species, Ceraphron sp. (Ceraphronoidea), Gasteruption sp. (Evanioidea), andOrthogonalys pulchella (Trigonalyoidea) as well as the nearly complete mt genome from another evaniomorphspecies,Megalyra sp. (Megalyroidea). Eachof thempossessesdramaticgenerearrangements, includingprotein-coding or rRNAgenes.Gene inversionswere identified inallof thesemtgenomes; forexample, the tworRNAgeneshave invertedandmoved intothenad2-cox1 junction in theMegalyra sp.mtgenome. Inaddition,wefoundtwocopiesofa10-bpcomplementary repeatat the beginning of rrnS and at the end of trnL2 in the Gasteruption sp. mt genome, consistent with recombination as the possible mechanism for gene inversion and long-range movement. Although each of the genomes contains a number of repeats of varying size, there was no consistent association of the size or number of repeats with the extent or type of gene rearrangement. The breakpoint distance analysis showed the Evaniomorpha has an intermediate rate of gene rearrangement. Sequence-based phylo-genetic analyses of 13 protein-coding and 2 rRNA genes in 22 hymenopteran taxa recovered a paraphyletic Evaniomorpha with the Aculeatanestedwithin it.Within the Evaniomorpha,our analyses confirmed the Trigonalyoidea + Megalyroideaas the sistergroup to the Aculeata and recovered a novel clade, Ceraphronoidea + Evanioidea. In contrast to previous hymenopteran phylogenetic studies, the internal relationships of the Evaniomorpha were highly supported and robust to the variation of alignment approach and phylogenetic inference approach