The 16, 470 bp nucleotide sequence of the mitochondrial genome (mitogenome) of an assassin bug from the reduviid subfamily Harpactorinae, Agriosphodrus dohrni, has been revealed. The entire genome encodes for two ribosomal RNA genes (rrnL and rrnS), 22 transfer RNA (tRNA) genes, 13 protein-coding genes, and a control region. The nucleotide composition is biased toward adenine and thymine (A+T = 72.2%). Comparative analysis with two other reduviid species Triatoma dimidiata and Valentia hoffmanni, exhibited highly conserved genome architectures including genome contents, gene order, nucleotide composition, codon usage, amino acid composition, as well as genome asymmetry. All protein-coding genes use standard mitochondrial initiation codons (methionine and isoleucine), except that nad1 starts with GTG. All tRNAs have the classic clover-leaf structure, except that the dihydrouridine (DHU) arm of tRNASer(AGN) forms a simple loop. Secondary structure comparisons of the two mitochondrial ribosomal subunits among sequenced assassin bugs show that the sequence and structure of rrnL is more conservative than that of rrnS. The presence of structural elements in the control region is also discussed, with emphasis on their implications in the regulation of replication and/or transcription of the reduviid mitogenome. The phylogenetic analyses indicated that within Reduviidae, Harpactorinae is a sister group to the Salyavatinae + Triatominae clade.

The complete sequence of the mitochondrial (mt) genome of the assassin bug, Sirthenea flavipes (Stål), was determined. The circular genome is 15, 961 bp long and contains a standard gene complement, i.e., the large and small ribosomal RNA (rRNA) subunits, 22 transfer RNA (tRNA) genes, 13 protein-coding genes (PCGs), and the 1, 295 bp control region. The nucleotide composition of S. flavipes mt genome is 71.8% AT-rich, reflected in the predominance of AT-rich codons in PCGs. Compared with the other three reduviid species available in complete mt genomes, the genome architecture as well as the nucleotide composition, codon usage, and amino acid composition reflected high similarity. All PCGs use standard initiation codons (ATN); however, ND4L and ND1 started with GTG. Canonical TAA and TAG termination codons are found in nine PCGs, the remaining four (COIII, ND3, ND5, and ND1) have incomplete termination codons. All tRNAs have the typical cloverleaf structure, except the dihydrouridine (DHU) arm of tRNA Ser (AGN) forms a simple loop as seen in many other metazoans. Secondary structure models of the ribosomal RNA genes of S. flavipes are presented and are similar to those proposed for other insects. The structure of rrnL is more conservative than that of rrnS among sequenced assassin bugs. The monophyly of Reduviidae is highly supported by Bayesian inferences, and the Peiratinae presents a sister position to the Triatominae+ (Salyavatinae + Harpactorinae).

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The mitochondrial genome of an assassin bug, Oncocephalus breviscutum Reuter, is a typical circular DNA molecule of 15,984 bp with 37 genes and a large control region. The gene order is identical to that of the putative ancestral arrangement of insects. Twelve protein-coding genes start with ATN codon and ND4L uses GTG. All of the 22 tRNAs, ranging from 61 to 70 bp, have the clover-leaf structure except for the dihydrouridine (DHU) arm of trnS2 forms a simple loop. The control region is 1345 bp in length and includes six tandem repeats of three 31-nt and three 145-nt units.