The number of reported mitochondrial genomes (mitogenomes) from the monotypic Lasiocampoidea has been limited until recently. In this study, we sequenced the complete mitogenome of the lappet moth, Kunugia undans (Lepidoptera: Lasiocampidae), and compared it to those of other lasiocampid species and macroheteroceran superfamilies (59 species in six superfamilies). The 15,570-bp long K. undans genome had the typical set of genes found in animal mitogenomes, with the exception of one additional trnR that are located between trnA and trnN loci. Considering that the two trnR copies are located in tandem with proper secondary structures and identical anticodons, a gene duplication event might be responsible for the presence of the two tRNAs. In summary, the general mitogenome characteristics of Lasiocampoidea did not differ greatly from the remaining macroheteroceran superfamilies, but it did exhibit some unique features.

The Gelechioidea is the second most species-rich group of Lepidoptera, but only limited number of mitochondrial genome (mitogenome) sequences is available. Thus, we sequenced the complete mitogenome of a gelechioid Hieromantis kurokoi (Lepidoptera: Stathmopodidae) to use the data for future study for the higher phylogeny of Ditrysia in Lepidoptera. The arrangement of the genome was identical to typical one found in Ditrysia (trnM-trnI-trnQ) (underline for inverted gene). The COI began with CGA, which has been designated as the start codon for majority of lepidopteran species, whereas other protein-coding genes (PCGs) began with the typical ATN codon. The 360-bp long A+T-rich region harbored the conserved sequence blocks Phylogenetic analysis using the 13 PCGs both by Bayesian inference (BI) and Maximum-likelihood (ML) methods indicated that H. kurokoi belonging to the family Stathmopodidae grouped together with within-familial species Atrijuglans hetaohei with the highest nodal support (BI, 1.0; ML, 100%).

In this study, we tested the effect of a range of insect orders including Trichoptera as outgroups for lepidopteran phylogeny. Phylogenetic analyses performed with four different partitioning schemes using the maximum-likelihood method provided four different topologies (T1-T4) and topological test most supported T1 topology. When the means of first principle component for nucleotide frequency between A/T and G/C of PCGs was considered Trichoptera, Diptera, Coleoptera, and Orthoptera tended to result in T1 topology more frequently in the given ingroup taxa and outgroups tested. This result contradicts to the general view that the sister taxon might be the best outgroup. The T1 topology was largely consistent with a recent large molecular dataset-based lepidopteran phylogeney, presenting the relationships ((((((((((Noctuoidea + Geometroidea) + (Bombycoidea + Lasiocampoidea)) + Drepanoidea) + Mimallonoidea) + Pyraloidea) + Gelechioidea) + Papilionoidea) + Tortricoidea) + (Gracillaroidea + Yponomeutoidea)) + Hepialoidea).

We sequenced the complete mitochondrial (mt) genome of Camponotus atrox (Hymenoptera: Formicidae) that is distributed only in Korea. This genome is 16,540 bp in size, contains typical sets of genes (13 protein-coding genes, 22 tRNAs, and two rRNAs). The C. atrox A+T-rich region is the longest in the sequenced ants as 1,402 bp and is comprised of an identical tandem repeat consisting of six 100-bp copies and one 96-bp copy. A total of 315 bp of intergenic-spacer sequences were spread over 23 regions. An attempt to align spacer sequences in ants turned out that alignment was mostly feasible among congeneric species, with a substantial sequence divergence, indicating the potential of these sequences as congeneric molecular markers. The A/T content in first and second codon positions of PCGs are similar in ants including C. atrox (73.9 vs. 72.3% on average). Estimation of degree of genetic divergence (e.g. non-synonymous substitution rate) with an increased taxon sampling among hymenopteran superfamilies indicated the presence of different rates of divergence between the suborders Symphyta and Apocrita as has previously been reported. The C. atrox mt genome has a unique gene arrangement, trnI-trnM-trnQ at the A+T-rich region and ND2 junction (underline for inverted gene), possibly originated from tandem duplication of trnM-trnI, resulting in trnM-trnI-trnM-trnI-trnQ and loss of first trnM and second trnI, resulting in trnI-trnM-trnQ.

The mulberry white caterpillar, Rondotia menciana, belongs to the lepidopteran family Bombycidae, in which the domestic silkworm, Bombyx mori is included. In this study, we describe the complete mitochondrial genome (mitogenome) sequences of the species in terms of general genomic features and characteristic features found in the A+T-rich region. The 15,364-bp long genome consisted of a typical set of genes (13 protein-coding genes, two rRNA genes and 22 tRNA genes) and one major non-coding A+T-rich region, with the typical arrangement found in Lepidoptera. Twelve of the 13 PCGs start with typical ATN codons, except for the COI, which begins with CGA. Twelve of the 13 PCGs have complete stop codon, except for COII, which ends up with a single T. The 360-bp long A+T-rich region harbored the conserved sequence blocks that are typically found in lepidopteran insects. Additionally, the A+T-rich region of R. menciana contained one tRNAMet-like structure, which has a proper anticodon and secondary structure.

We report the complete mitochondrial genome (mitogenome) of Apodemia mormo, which belongs to the lepidopteran family Riodinidae. The 15,262-bp long complete genome is comprised of 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and one major non-coding A+T-rich region, with the arrangement typically found in majority of Lepidoptera. The genes of A. mormo are interleaved with a total of 168 bp, which are spread over 16 regions and overlap in a total of 58 bp at eight locations. All tRNAs of the A. mormo mitogenome formed typical cloverleaf structure, except for tRNASer(AGN), which formed the truncated dihydrouridine arm. COI gene started with CGA, instead of canonical ATN as seen in other Lepidoptera. The 349-bp long A+T-rich region harbored the conserved sequence blocks, such as ATAGA motif, poly-T stretch, the conserved ATTTA sequence, and microsatellite A/T repeat that are typically found in Lepidoptera, but absent for tRNA-like pseudogene.

We newly sequenced mitogenomes of five skippers belonging to Lepidoptera to obtain further insight into characteristics of butterfly mitogenomes and performed phylogenetic reconstruction using all available gene sequences (PCGs, rRNAs, and tRNAs) from 85 species in 19 families in eight superfamilies. The general genomic features found in the butterflies also were found in the five skippers: a high A/T composition (79.3% - 80.9%), dominant usage of TAA stop codon, similar skewness pattern in various levels, consistently long intergenic spacer sequence between tRNAGln - ND2 (64-87 bp), the ATACTAA motif betweent RNASer(UCN) and ND1, and characteristic features of the A+T-rich region (the motif ATAGA, varying length of poly-T stretch, and poly-A stretch). The start codon for COI was CGA in four skippers as typical, but Lobocla bifasciatus evidently possessed canonical ATG as start codon. Phylogenetic analyses mainly yielded the consensus superfamilial relationships ((((((Bombycoidea + Noctuoidea + Geometroidea) + Pyraloidea) + Papilionoidea) + Tortricoidea) + Yponomeutoidea) + Hepialoidea) with a high support for most nodes, confirming the validity of Macroheterocera and its sister relationship to Pyraloidea. Within Rhopalocera the familial relationships (Papilionidae + (Hesperiidae + (Pieridae + ((Lycaenidae + Riodinidae) + Nymphalidae))) were strongly supported, confirming invalidity of the superfamily Hesperioidea. On the other hand, superfamilial relationships among Noctuoidea, Geometroidea, and Bombycoidea and the familial relationships among Saturniidae, Sphingidae, and Bombycidae were dubious, requiring further representative taxon sampling.

Up to now the complete mitochondrial genome (mitogenome) sequences of only three species of clitellate have been available. We have determined the complete mitogenome sequences of the elusive Burmese giant earthworm Tonoscolex birmanicus (Clitellata: Megascolecidae), which is endemic to Myanmar. The 15,170-bp long genome contains the 37 genes typical of metazoan mitogenomes [13 protein-coding genes (PCG), two rRNA genes and 22 tRNA genes] and one major non-coding region. All of the 37 genes are transcribed from the same DNA strand. The arrangement of the T. birmanicus mitogenome is identical to that of two within-ordinal species Lumbricus terrestris and Perionyx excavates. All 13 PCGs start with the ATG. For the stop codon, only six PCGs end with the TAA, whereas the remaining ones ends with the incomplete stop codon, T. Genes overlap in a total of 14 bp in five locations, and harbor a total of 16 bp of intergenic spacer sequences in nine locations.

Glyphodes quadrimaculalis (Lepidoptera: Crambidae) feed on a root tuber of Cynanchum wilfordii (Asclepiadaceae) that is one of the most famous traditional medicines in Korea. The genus Glyphodes includes ~130 species distributed worldwide, so the complete mitochondrial genome (mitogenome) would be helpful for bio-identification, biogeographic studies, and multigene-based phylogeny. The 15,255-bp long G. quadrimaculalis genome comprises 37 typical genes and one large non-coding region, with the typical arrangement found in Lepidoptera. Of the 13 protein coding genes (PCGs), 12 begin with typical start codons found in insect mitochondrial PCGs, but the COI gene starts with atypical CGA. One of the noteworthy features of the genome includes the presence of a 51-bp long non-coding space sequence located between tRNAGln and ND2 that reveals high sequence homology (71.4%) to the neighboring ND2 gene, indicating the origin of the region by partial duplication of the ND2 gene.

The larch hawk moth, Sphinx morio, belongs to the lepidopteran family Sphingidae that has long been studied as a family of model insects in a diverse field. In this study, we describe the complete mitochondrial genome (mitogenome) sequences of the species in terms of general genomic features and characteristic short repetitive sequences found in the A+T-rich region. The 15,299-bp long genome consisted of a typical set of genes (13 protein-coding genes, two rRNA genes and 22 tRNA genes) and one major non-coding A+T-rich region, with the typical arrangement found in Lepidoptera. The 316-bp long A+T-rich region located between srRNA and tRNAMet harbored the conserved sequence blocks that are typically found in lepidopteran insects. Additionally, the A+T-rich region of S. morio contained three characteristic repeat sequences that are rarely found in Lepidoptera: two identical 12-bp repeat, three identical 5-bp long tandem repeat, and six nearly identical 5~6 bp long repeat sequences.

In the present study, the 17,694-bp long complete mitochondrial genome (mitogenome) of the dwarf honey bee, Apis florea (Hymenoptera: Apidae), is described with an emphasis on the noteworthy triplicated tRNAser(AGN) region and an extraordinary long A+T-rich region with repeat regions. The gene arrangement of A. florea mitogenome is identical to that of A. mellifera, but has triplicated tRNASer(AGN), each of which contains the precedent 44 bp-long and following another 64 bp-long repeats plus one complete first repeat abutting to tRNAMet. A total of 1,610-bp long two repeat regions in 1,987 bp-long A+T-rich region is composed of nearly identical 141 ~ 219-bp long five tandem repeats and 50 ~ 52-bp long 12 tandem repeats that are encompassed by three non-repeat sequences. One of the common interpretations for such repeat sequence is slipped-strand mispairing and unequal crossing-over events during DNA replication.

Gene arrangement in the mitochondrial genome (mitogenome) has been regarded as an important evolutionary event that is useful as a phylogenetic signal. The mountainous duskywing, Erynnis montanus, belongs to a lepidopteran family Hesperiidae. We sequenced 15,530-bp long complete mitogenome of the species. The genome has the typical gene content of animals (13 protein-coding genes, two rRNA genes, 22 tRNA genes, and one major non-coding A+T-rich region). Further, E. montanus mitogenome also contained a high A/T content in the whole genome (81.7%) and the CGA (arginine) as the start codon for the COI gene, as typical in lepidopteran mitogenome. However, unlike other lepidopteran species, including two sequenced skippers, the E. montanus mitogenome has a unique arrangement tRNASer-tRNAAsn, instead of the tRNAAsn-tRNASer found unanimously in other lepidopteran species, providing a new gene arrangement in Lepidoptera. Such rearrangement probably was likely caused by duplication of gene block tRNASer-tRNAAsn and subsequent random loss of tRNAAsn in the first copy and tRNASer in the second copy, resulting in the arrangement tRNASer-tRNAAsn. Considering current phylogenetic relationships among available lepidopteran groups in connection with lepidopteran gene arrangement the new gene arrangement found in E. montanus seems to be apomorphy, requiring cautious interpretation as a phylogenetic signal.