Phylogenetic approaches for the analysis of mitochondrial genome sequence data in the Hymenoptera--a lineage with both rapidly and slowly evolving mitochondrial genomes.

We entirely sequenced two new hymenopteran mitochondrial genomes (Cephus cinctus and Orussus occidentalis), and a substantial portion of another three hymenopterans (Schlettererius cinctipes, Venturia canescens, and Enicospilus). We analyze them together with nine others reported in the literature. We establish that the rate of genetic divergence is two to three times higher among some Hymenoptera when compared with others, making this a group with both long and short phylogenetic branches. We then assessed the ability of a range of phylogenetic approaches to recover seven uncontroversial relationships, when lineages show markedly different rates of molecular evolution. This range encompassed maximum parsimony and Bayesian analysis of (i) amino acid data, (ii) nucleotide data, and (iii) nucleotide data excluding third codon positions. Unpartitioned analyses were compared with partitioned analyses, with the data partitioned by codon position (ribosomal genes were placed in a separate partition). These analyses indicated that partitioned, Bayesian analysis of nucleotide data, excluding 3rd codon positions, recovered more of the uncontroversial relationships than any other approach. These results suggest that the analysis of complete mitochondrial genome sequences holds promise for the resolution of hymenopteran superfamily relationships.