Comparative mitochondrial genome analysis of Grammodes geometrica and other noctuid insects reveals conserved mitochondrial genome organization and phylogeny

Characterization and Molecular Phylogenetic Analysis of Subfamily Erebinae (Lepidoptera: Noctuoidea: Erebidae) Using Five Complete Mitochondrial Genomes

In this study, the complete mitogenomes of Sympis rufibasis, Lacera noctilio, Oxyodes scrobiculata, Mocis undata, and Artena dotata were newly sequenced to bring up-to-date the database using the next-generation sequencing methods. The gene order of all sequenced mitogenomes was identical consisting of 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and a non-coding A+T-rich region, which were common to other Lepidopteran insects. All protein-coding genes (PCGs) initiated with a canonical ATN codon and ended with TAN or an incomplete stop codon, single T. The A+T-rich region of S. rufibasis, L. noctilio, O. scrobiculata, M. undata, and A. dotata are 406 bp, 462 bp, 372 bp, 410 bp, and 406 bp long, respectively, containing number of characteristics that are distinctive to Noctuoidea moths. We analyzed concatenated amino acid sequences of protein-coding genes not including rRNAs, using Maximum Likelihood and Bayesian Inference methods. The phylogenetic analyses indicated that the tribe relationships within Erebinae were reconstructed as (Sypnini+((Erebini 1+Poaphilini 1)+((Euclidiini+Catocalini+(Hypopyrini+Erebini 2))+((Hulodini+(Poaphilini 2+Ophiusini))))). Phylogenetic analyses supported and confirmed the monophyly of the subfamilies' relationships as follows: (Hypeninae+Lymantriinae)+((Scoliopterginae+((Calpinae+Erebinae)+((Herminiinae+Aganainae)+Arctiinae)))) within Erebidae.

Complete Mitochondrial Genome Characterization of Schrankia costaestrigalis (Insecta: Erebidae: Hypenodinae) and Its Phylogenetic Implication

The pinion-streaked snout Schrankia costaestrigalis is a new potato pest that has recently been recorded in China. In this study, we analyzed the complete mitochondrial genome of S. costaestrigalis. The results revealed the mitogenome (GenBank: OQ181231) to occur as a circular DNA molecule of 16,376 bp with 51.001% AT content, including 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (rRNA) genes, and 1 control region. Notably, the PCGs exhibited typical ATN (Met) start codons, including cox1, which deviated from the usual CGA start codon observed in other lepidopteran mitogenomes, and followed the conventional TAN stop codons. The 22 tRNA genes demonstrated the ability to form a cloverleaf structure, with the exception of trnS1-NCU, which lacked the DHU arm present in other Erebidae mitogenomes. Additionally, conserved motifs like "ATAGA + poly-T (19 bp) stretch" and five microsatellite-like elements (TA) were identified in the AT-rich region. The phylogenetic trees revealed that the Hypenodinae subfamily forms an independent lineage closely related to Erebinae and Catocalinae. The comprehensive mitogenome of S. costaestrigalis will greatly enhance future studies focused on the molecular classification and phylogenetic understanding of the Hypenodinae subfamily within the larger family Erebidae.

Phylogenomics including the newly sequenced mitogenomes of two moths (Noctuoidea, Erebidae) reveals Ischyja manlia (incertae sedis) as a member of subfamily Erebinae

We sequenced the mitogenomes of two Erebid species, namely Ischyja manlia (Cramer, 1776) and Rusicada privata (Walker, 1865) to analyse the phylogenetic relationship and to establish the taxonomic position of incertae sedis members of the family Erebidae. The two circular genomes of I. manlia and R. privata were 15,879 bp and 15,563 bp long, respectively. The gene order was identical, containing 13 protein-coding genes (PCGs), 22 tRNA genes, two rRNA genes, and an A + T-rich region. The nucleotide compositions of the A + T-rich region of both mitogenomes were similar: 80.65% for R. privata, and 81.09% for I. manlia. The AT skew and GC skew were slightly positive in I. manlia and negative in R. privata. In I. manlia and R. privata, except for cox1 which started with CGA and TTG codons, all the other 12 PCGs started with ATN codon. The A + T-rich regions of I. manlia and R. privata were 433 and 476 bp long, respectively, and contained common characteristics of Noctuoidea moths. At present, Ischyja is treated as Erebinae incertae sedis. However, phylogenetic analysis conducted in the present study reveals that the genus Ischyja is most likely to be a member of the subfamily Erebinae.

Characterization of four mitochondrial genomes from superfamilies Noctuoidea and Hyblaeoidea with their phylogenetic implications

In the present study, the newly sequenced mitogenomes of three Noctuoid and one Hyblaeoid (Insecta: Lepidoptera) species were annotated based on next-generation sequence data. The complete mitogenome lengths of Oraesia emarginata, Actinotia polyodon, Odontodes seranensis, and Hyblaea puera were 16,668 bp, 15,347 bp, 15,419 bp, and 15,350 bp, respectively. These mitogenomes were found to encode 37 typical mitochondrial genes (13 protein-coding, 22 transfer RNA, 2 ribosomal RNA) and a control region, similar to most Lepidoptera species. Maximum likelihood (ML) methods and Bayesian inference (BI) were used to reconstruct the phylogenetic relationships of the moths. This study showed the relationships of Noctuoid families as follows: (Notodontidae + (Erebidae + (Nolidae + (Euteliidae + Noctuidae)))). Furthermore, the species H. puera was separately clustered from the Noctuoidea member groups. Till now, the species from the superfamily Hyblaeoidea have not been discussed for their phylogenetic relationships. In this study, the complete mitochondrial genome of one species from the superfamily Hyblaeoidea was analysed.

Characterization of Seventeen Complete Mitochondrial Genomes: Structural Features and Phylogenetic Implications of the Lepidopteran Insects

Lepidoptera (moths and butterflies) are widely distributed in the world, but high-level phylogeny in Lepidoptera remains uncertain. More mitochondrial genome (mitogenome) data can help to conduct comprehensive analysis and construct a robust phylogenetic tree. Here, we sequenced and annotated 17 complete moth mitogenomes and made comparative analysis with other moths. The gene order of trnM-trnI-trnQ in 17 moths was different from trnI-trnQ-trnM of ancestral insects. The number, type, and order of genes were consistent with reported moths. The length of newly sequenced complete mitogenomes ranged from 14,231 bp of Rhagastis albomarginatus to 15,756 bp of Numenes albofascia. These moth mitogenomes were typically with high A+T contents varied from 76.0% to 81.7% and exhibited negative GC skews. Among 13 protein coding genes (PCGs), some unusual initiations and terminations were found in part of newly sequenced moth mitogenomes. Three conserved gene-overlapping regions and one conserved intergenic region were detected among 17 mitogenomes. The phylogenetic relationship of major superfamilies in Macroheterocera was as follows: (Bombycoidea + Lasiocampoidea) + ((Drepanoidea + Geometroidea) + Noctuoidea)), which was different from previous studies. Moreover, the topology of Noctuoidea as (Notodontidae + (Erebidae + Noctuidae)) was supported by high Bayesian posterior probabilities (BPP = 1.0) and bootstrapping values (BSV = 100). This study greatly enriched the mitogenome database of moth and strengthened the high-level phylogenetic relationships of Lepidoptera.

Complete mitochondrial genomes of Boigakraepelini and Hebiuscraspedogaster (Reptilia, Squamata, Colubridae) and their phylogenetic implications

The complete sequence of the mitochondrial genome is a powerful tool for studying phylogenetic relationships and molecular evolution in various species. In this work, the mitogenomes of Boigakraepelini and Hebiuscraspedogaster were sequenced and characterized for the first time. The lengths of the B.kraepelini and H.craspedogaster mitogenomes were 17,124 bp and 17,120 bp, respectively, and both included 13 protein-coding genes, 22 tRNAs, two rRNAs and two control regions. The arrangements of these mitochondrial genes were the same in B.kraepelini and H.craspedogaster. In addition, both genome compositions showed A+T bias (59.03%, 60.93%) and had positive AT skews (0.179, 0.117) and negative GC skews (-0.397, -0.348). The phylogenetic results illustrated a close relationship between B.kraepelini and the genus Lycodon. Moreover, H.craspedogaster was clustered with other Hebius snakes and closely related to other Natricinae species. These results will provide references for further research on the phylogeny of Colubridae.

Enhanced Resolution of Evolution and Phylogeny of the Moths Inferred from Nineteen Mitochondrial Genomes

The vast majority (approximately 90%) of Lepidoptera species belong to moths whose phylogeny has been widely discussed and highly controversial. For the further understanding of phylogenetic relationships of moths, nineteen nearly complete mitochondrial genomes (mitogenomes) of moths involved in six major lineages were sequenced and characterized. These mitogenomes ranged from 15,177 bp (Cyclidia fractifasciata) to 15,749 bp (Ophthalmitis albosignaria) in length, comprising of the core 37 mitochondrial genes (13 protein-coding genes (PCGs) + 22 tRNAs + two rRNAs) and an incomplete control region. The order and orientation of genes showed the same pattern and the gene order of trnM-trnI-trnQ showed a typical rearrangement of Lepidoptera compared with the ancestral order of trnI-trnQ-trnM. Among these 13 PCGs, ATP8 exhibited the fastest evolutionary rate, and Drepanidae showed the highest average evolutionary rate among six families involved in 66 species. The phylogenetic analyses based on the dataset of 13 PCGs suggested the relationship of (Notodontidae + (Noctuidae + Erebidae)) + (Geometridae + (Sphingidae + Drepanidae)), which suggested a slightly different pattern from previous studies. Most groups were well defined in the subfamily level except Erebidae, which was not fully consistent across bayesian and maximum likelihood methods. Several formerly unassigned tribes of Geometridae were suggested based on mitogenome sequences despite a not very strong support in partial nodes. The study of mitogenomes of these moths can provide fundamental information of mitogenome architecture, and the phylogenetic position of moths, and contributes to further phylogeographical studies and the biological control of pests.

A supertree of Northern European macromoths

Ecological and life-history data on the Northern European macromoth (Lepidoptera: Macroheterocera) fauna is widely available and ideal for use in answering phylogeny-based research questions: for example, in comparative biology. However, phylogenetic information for such studies lags behind. Here, as a synthesis of all currently available phylogenetic information on the group, we produce a supertree of 114 Northern European macromoth genera (in four superfamilies, with Geometroidea considered separately), providing the most complete phylogenetic picture of this fauna available to date. In doing so, we assess those parts of the phylogeny that are well resolved and those that are uncertain. Furthermore, we identify those genera for which phylogenetic information is currently too poor to include in such a supertree, or entirely absent, as targets for future work. As an aid to studies involving these genera, we provide information on their likely positions within the macromoth tree. With phylogenies playing an ever more important role in the field, this supertree should be useful in informing future ecological and evolutionary studies.

Novel gene rearrangement in the mitochondrial genome of Anastatus fulloi (Hymenoptera Chalcidoidea) and phylogenetic implications for Chalcidoidea

The genus Anastatus comprises a large group of parasitoids, including several biological control agents in agricultural and forest systems. The taxonomy and phylogeny of these species remain controversial. In this study, the mitogenome of A. fulloi Sheng and Wang was sequenced and characterized. The nearly full-length mitogenome of A. fulloi was 15,692 bp, compromising 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and a control region (CR). The total A + T contents were 83.83%, 82.18%, 87.58%, 87.27%, and 82.13% in the whole mitogenome, 13 PCGs, 22 tRNA genes, 2 rRNA genes, and CR, respectively. The mitogenome presented negative AT skews and positive GC skews, except for the CR. Most PCGs were encoded on the heavy strand, started with ATN codons, and ended with TAA codons. Among the 3736 amino acid-encoding codons, TTA (Leu1), CGA (Arg), TCA (Ser2), and TCT (Ser2) were predominant. Most tRNAs had cloverleaf secondary structures, except trnS1, with the absence of a dihydrouridine (DHU) arm. Compared with mitogenomes of the ancestral insect and another parasitoid within Eupelmidae, large-scale rearrangements were found in the mitogenome of A. fulloi, especially inversions and inverse transpositions of tRNA genes. The gene arrangements of parasitoid mitogenomes within Chalcidoidea were variable. A novel gene arrangement was presented in the mitogenome of A. fulloi. Phylogenetic analyses based on the 13 protein-coding genes of 20 parasitoids indicated that the phylogenetic relationship of 6 superfamilies could be presented as Mymaridae + (Eupelmidae + (Encyrtidae + (Trichogrammatidae + (Pteromalidae + Eulophidae)))). This study presents the first mitogenome of the Anastatus genus and offers insights into the identification, taxonomy, and phylogeny of these parasitoids.

Complete mitochondrial genome sequencing of Oxycarenus laetus (Hemiptera: Lygaeidae) from two geographically distinct regions of India

Oxycarenus laetus is a seed-sap sucking pest affecting a variety of crops, including cotton plants. Rising incidence and pesticide resistance by O. laetus have been reported from India and neighbouring countries. In this study, O. laetus samples were collected from Bhatinda and Coimbatore (India). Pure mtDNA was isolated and sequenced using Illumina MiSeq. Both the samples were found to be identical species (99.9%), and the complete genome was circular (15,672 bp), consisting of 13 PCGs, 2 rRNA, 23 tRNA genes, and a 962 bp control region. The mitogenome is 74.1% AT-rich, 0.11 AT, and - 0.19 GC skewed. All the genes had ATN as the start codon except cox1 (TTG), and an additional trnT was predicted. Nearly all tRNAs folded into the clover-leaf structure, except trnS1 and trnV. The intergenic space between trnH and nad4, considered as a synapomorphy of Lygaeoidea, was displaced. Two 5 bp motifs AATGA and ACCTA, two tandem repeats, and a few microsatellite sequences, were also found. The phylogenetic tree was constructed using 36 mitogenomes from 7 super-families of Hemiptera by employing rigorous bootstrapping and ML. Ours is the first study to sequence the complete mitogenome of O. laetus or any Oxycarenus species. The findings from this study would further help in the evolutionary studies of Lygaeidae.

The complete mitochondrial genome of Poecilocoris druraei (Linnaeus, 1771) (Hemiptera: Scutelleridae) and its phylogenetic implications

The complete mitochondrial genome sequence of Poecilocoris druraei was sequenced and analyzed. The 16,524 bp mitogenome of P. druraei contained 21 tRNA genes, two rRNA genes, 13 protein-coding genes (PCGs), and a control region. Most PCGs used standard ATG start codons and complete TAA ermination codons. Phylogenetic analysis indicated that P. druraei is closed related with P. nepalensis.

Comparative mitochondrial genome analysis of Eudocima salaminia (Cramer, 1777) (Lepidoptera: Noctuoidea), novel gene rearrangement and phylogenetic relationship within the superfamily Noctuoidea

The species Eudocima salaminia (Cramer, 1777) commonly known as the fruit-piercing moth belongs to family Erebidae. Its distribution varies from India and across South-east Asia, pacific islands and parts of Australia. The insect is a devastating pest of citrus, longans and lychees. In the present study, complete mitochondrial genome of Eudocima salaminia was sequenced and analyzed using Illumina sequencer. The phylogenetic tree was reconstructed based on nucleotide sequences of 13 PCGs using Maximum likelihood method-General Reversible mitochondrial (mtREV) model. The mitogenome has 15,597 base pairs (bp) in length, comprising of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, two ribosomal RNA (rRNA) genes and A + T-rich region. All protein-coding genes (PCGs) initiate with canonical start codon ATN. The gene order (trnQ-trnI-trnM) of tRNA shows a different rearrangement compared to ancestral insect gene order (trnI-trnQ-trnM). Almost all tRNAs have a typical cloverleaf secondary structure except for trnS1 (AGN) which lacks the dihydrouridine arm. At the beginning of the control region, we observed a conserved polyT", motif "ATTTA" and microsatellite (TA)n element. There are 21 intergenic regions and five overlapping regions ranging from 1 to 73 bp and 1 to 8 bp, respectively. The phylogenetic relationships based on nucleotide sequences of 13 PCGs using Maximum likelihood method showed the family level relationships as (Notodontidae + (Euteliidae + Noctuidae + (Erebidae + Nolidae))). The present study represents the similarity to phylogenetic analysis of Noctuoidea mitogenome. Moreover, the family Erebidae is the sister to the families of (Euteliidae + Noctuidae + Nolidae).

Mitochondrial genome of Diachrysia nadeja (Lepidoptera: Noctuoidea: Noctuidae) and phylogenetic analysis

Diachrysia nadeja is a polyphagous herbivorous moth within the family Noctuidae. In this study, we sequenced and analyzed the complete mitochondrial genome (mitogenome) of D. nadeja. This mitogenome was 15,242 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and 2 ribosomal RNA unit genes (rRNAs). Gene order was conserved and identical to most other previously sequenced Noctuidae. Except for cox1 started with CGA, all other PCGs started with the standard ATN codons. Most of the PCGs terminated with the stop codon TAA, whereas cox1, cox2, and nad4 end with the incomplete codon T−. The whole mitogenome exhibited heavy AT nucleotide bias (80.5%). Phylogenetic analysis showed that D. nadeja got together with three Ctenoplusia species (C. agnata, C. limbirena, and C. albostriata) with high support value, indicating Diachrysia had a closer relationship with Ctenoplusia within Noctuidae.

Organization and phylogenetic relationships of the mitochondrial genomes of Speiredonia retorta and other lepidopteran insects

In this study, we analyzed the complete mitochondrial genome (mitogenome) of Speiredonia retorta, which is a pest and a member of the Lepidoptera order. In total, the S. retorta mitogenome was found to contain 15,652 base pairs encoding 13 protein-coding genes (PCGs), 22 tRNAs, 2 rRNAs, as well as an adenine (A) + thymine (T)-rich region. These findings were consistent with the mitogenome composition of other lepidopterans, as we identified all 13 PCGs beginning at ATN codons. We also found that 11 PCGs terminated with canonical stop codons, whereas cox2 and nad4 exhibited incomplete termination codons. By analyzing the mitogenome of S. retorta using Bayesian inference (BI) and maximum likelihood (ML) models, we were able to further confirm that this species is a member of the Erebidae family.

The complete mitochondrial genome of medicinal fungus Taiwanofungus camphoratus reveals gene rearrangements and intron dynamics of Polyporales

Taiwanofungus camphoratus is a highly valued medicinal mushroom that is endemic to Taiwan, China. In the present study, the mitogenome of T. camphoratus was assembled and compared with other published Polyporales mitogenomes. The T. camphoratus mitogenome was composed of circular DNA molecules, with a total size of 114,922 bp. Genome collinearity analysis revealed large-scale gene rearrangements between the mitogenomes of Polyporales, and T. camphoratus contained a unique gene order. The number and classes of introns were highly variable in 12 Polyporales species we examined, which proved that numerous intron loss or gain events occurred in the evolution of Polyporales. The Ka/Ks values for most core protein coding genes in Polyporales species were less than 1, indicating that these genes were subject to purifying selection. However, the rps3 gene was found under positive or relaxed selection between some Polyporales species. Phylogenetic analysis based on the combined mitochondrial gene set obtained a well-supported topology, and T. camphoratus was identified as a sister species to Laetiporus sulphureus. This study served as the first report on the mitogenome in the Taiwanofungus genus, which will provide a basis for understanding the phylogeny and evolution of this important fungus.

Complete mitochondrial genome of Spilosoma lubricipedum (Noctuoidea: Erebidae) and implications for phylogeny of noctuid insects

Mitochondrial genomes (mitogenomes) have been widely used for studies on phylogenetic relationships and molecular evolutionary biology. Here, the complete mitogenome sequence of Spilosoma lubricipedum (Noctuoidea: Erebidae: Arctiinae) was determined (total length 15,375 bp) and phylogenetic analyses S. lubricipedum were inferred from available noctuid sequence data. The mitogenome of S. lubricipedum was found to be highly A + T-biased (81.39%) and exhibited negative AT- and GC-skews. All 13 protein-coding genes (PCGs) were initiated by ATN codons, except for cox1 with CGA. All tRNAs exhibited typical clover-leaf secondary structures, except for trnS1. The gene order of the S. lubricipedum mitogenome was trnM-trnI-trnQ-nad2. The A + T-rich region of S. lubricipedum contained several conservative features common to noctuid insects. Phylogenetic analysis within Noctuoidea was carried out based on mitochondrial data. Results showed that S. lubricipedum belonged to Erebidae and the Noctuoidea insects could be divided into five well-supported families (Notodontidae + (Erebidae + (Nolidae + (Euteliidae + Noctuidae)))).

Phylogenetic relationships of Limacodidae and insights into the higher phylogeny of Lepidoptera

To determine the systematic status of family Limacodidae within Lepidoptera, the complete mitochondrial genome (mitogenome) of Thosea sinensis (Lepidoptera: Zygaenoidea: Limacodidae) was sequenced. The genome is 15,544 base pairs (bp), including 13 protein-coding genes (PCGs), two ribosomal RNAs (rRNAs), 22 transfer RNAs (tRNAs), and an AT-rich region. These characteristics are similar to of other lepidopterans. The gene order of T. sinensis is identical to that of Ditrysia lepidopterans. The nucleotide composition of the T. sinensis mitochondrial genome is highly biased toward A + T nucleotides (81.1%) and exhibits negative AT and GC skew. All the other 13 PCGs except cox1 are initiated by ATN codons. All tRNA genes are folded into the typical cloverleaf secondary structure, except for trnS1, which lacked the dihydrouridine (DHU) stem. There are 20 intergenic spacer regions ranging from 1 to 56 bp in length, and two gene overlap regions throughout the entire genome. The AT-rich region includes the ATAGA motif, followed by a 19-bp poly T stretch, a microsatellite-like (AT)₁₀, and a poly-A element. Analysis of phylogenetic relationships indicated that T. sinensis belongs to the Limacodidae, and the monophyly of each lepidopteran family was well supported.

Characterisation and phylogenetic analysis of the complete mitochondrial genome of Ctenoplusia albostriata (Lepidoptera: Noctuidae: Plusiinae)

Ctenoplusia albostriata is a pest of composite plants such as Calendula officinalis L. and Dahlia pinnata. In this study, we sequenced and analyzed the complete mitochondrial genome (mitogenome) of C. albostriata. This mitogenome was 15,284 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and 2 ribosomal RNA unit genes (rRNAs). Gene order was conserved and was found to be identical to most other previously sequenced Noctuidae. The whole mitogenome exhibited heavy AT nucleotide bias (80.9%). Except for cox1 started with CGA, all other PCGs started with the standard ATN codons. Most of the PCGs terminated with the stop codon TAA, whereas cox1, cox2 and nad4 end with the incomplete codon T--. Phylogenetic analysis showed that the mitogenome of C. albostriata was similar to C. agnata and C. limbirena, and the subfamily Plusiinae was close to Acronictinae, Heliothinae, Amphipyrinae, Noctuinae, and Hadeninae.

The conserved mitochondrial genomes of Drosophila mercatorum (Diptera: Drosophilidae) with different reproductive modes and phylogenetic implications

Fruit flies (Drosophilidae: Drosophila) are commonly found in daily life and have long been used as model organisms in biology researches. Drosophila mercatorum is one important member of the Drosophila genus and has been used to study centrosome assembly of cells. In this study, we sequenced and analyzed the mitochondrial genome (mitogenome) of D. mercatorum, finding that it contains the typical structure of 37 genes and a control region. The arrangement of mitochondrial genes is in accordance with that in other Drosophila species, which is considered the ancestral organization of insects' mitogenomes. Phylogenetic analyses were performed based on 23 species of Drosophila. Our results supported two monophyletic subgenera, Drosophila and Sophophora, except for D. willistoni which was presented as an early offshoot of Drosophila. The topology ((D. yakuba + D. erecta) + D. melanogaster) was supported. We further compared the mitogenomes of parthenogenesis and sexual reproduction strains of D. mercatorum. However, only one synonymous mutation in COI gene was identified, indicating mitogenomic evolution is not strongly correlated with the different reproductive modes of this species. Taken together, our results demonstrate that mitogenome is an effective molecular marker that can be further used in phylogenetic studies of Drosophila and other organisms.

Complete mitochondrial genome of two Thitarodes species (Lepidoptera, Hepialidae), the host moths of Ophiocordyceps sinensis and phylogenetic implications

Thitarodes (Lepidoptera, Hepialidae) is the only genus that hosts to the Ophiocordyceps sinensis, a traditional Chinese medicine considered as a powerful medicinal supplement. In this study, the complete mitochondrial genomes (mitogenomes) of two species, T. damxungensis and T. pui, have been sequenced, which are 15,928 bp and 15,362 bp in size respectively, and both contain 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs and an AT-rich region. Like other hepialoids, the gene arrangement of the mitogenomes of T. damxungensis and T. pui is identical to the ancestral arrangement but differs from those of other lepidopteran species on account of the different arrangements of trnM, trnI, and trnQ. The size of AT-rich region is 545 bp in T. damxungensis and 1030 bp in T. pui. Tandem repetition in the AT-rich region is responsible for the length difference of the A + T-rich region in both species. In Hepialidae, the phylogenetic study based on the dataset of the sequences that combined the protein-coding genes and RNA genes suggested that the species T. yunnanensis should still belong to the genus Thitarodes rather than Ahamns, which is different from the results based on the traditional phylogeny.

Complete mitochondrial genomes of Bittacus strigosus and Panorpa debilis and genomic comparisons of Mecoptera

Mitochondrial genomes play a significant role in reconstructing phylogenetic relationships and revealing molecular evolution of insects. However, only four mitochondrial genomes were reported in Mecoptera to date. Here, we obtained two new complete mitochondrial genomes of the hangingfly Bittacus strigosus Hagen, 1861 and the scorpionfly Panorpa debilis Westwood, 1846. The results show that the complete mitogenome sequences of B. strigosus and P. debilis are 15,825 and 17,018 bp, respectively, both containing 37 genes and one control region. The mecopteran mitogenomes are highly similar in A + T bias, AT-skew, and GC-skew. Tandem repeats of the control region were discovered in Mecoptera for the first time. The sliding window, genetic distance, and Ka/Ks ratio analyses indicate the purifying selection of 13 protein-coding genes, the lowest evolutionary rate of cox1, and the highest sequence variability of atp8. Considering the sufficiently large size, fast evolution, and high ratio of Ka/Ks, nad4L and nad6 are regarded as potential markers for future phylogenetic analyses, population genetics, and species delimitations in Mecoptera. The phylogenetic relationships were reconstructed for four families of Mecoptera based on all six available mitogenomes using Bayesian inference and maximum likelihood methods. The phylogeny is presented as Boreidae + (Nannochoristidae + (Bittacidae + Panorpidae)).