The mitochondrial genome of the butterfly Papilio xuthus (Lepidoptera: Papilionidae) and related phylogenetic analyses

Genetic Population Structure of Dastarcus helophoroides (Coleoptera: Bothrideridae) From Different Long-Horned Beetle Hosts Based on Complete Sequences of Mitochondrial COI

Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is an important natural enemy of long-horned beetles in China, Japan, and Korea. In this study, the genetic sequence of cytochrome oxidase subunit Ι was used to investigate the genetics and relationships within and among D. helophoroides populations collected from five different geographic locations. We used principal component analysis, heatmap, and Venn diagram results to determine the relationship between haplotypes and populations. In total, 26 haplotypes with 51 nucleotide polymorphic sites were defined, and low genetic diversity was found among the different populations. Significant genetic variations were observed mainly within populations, and no correlation was found between genetic distribution and geographical distance. Low pairwise fixation index values (-0.01424 to 0.04896) and high gene flows show that there was high gene exchange between populations. The codistributed haplotype DH01 was suggested to be the most ancestral haplotype, and other haplotypes were thought to have evolved from it through several mutations. In four of the populations, both common haplotypes (DH01, DH03, and DH22) and unique haplotypes were found. Low genetic diversity among different populations is related to a relatively high flight capacity, host movement, and human-aided dispersal of D. helophoroides. The high gene exchange and typically weak population genetic structure among five populations, especially among populations of Anoplophora glabripennis (Motschulsky), Monochamus alternatus (Hope), and Massicus raddei (Blessig), may suggest that these populations cross naturally in the field.

The mitochondrial genome of the lepidopteran host cadaver (Thitarodes sp.) of Ophiocordyceps sinensis and related phylogenetic analysis

To understand the phylogeny of the host insect (Thitarodes sp.) of the fungus Ophiocordyceps sinensis, we sequenced, annotated and characterized the complete mitochondrial (mt) genome of the host cadaver of a natural O. sinensis. Further, we compared the Thitarodes sp. mt genome with those of the other 7 sequenced Hepialidae and examined the phylogenetic relationships using a constructed Maximum Likelihood (ML) phylogenetic tree and mt genomic features (genetic distances and intergenic spacers). The mt genome is a circular molecule of 16,280bp in length with a high A+T content (81.20%) and contains 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and an AT-rich region. The gene arrangement is identical to the ancestral arrangement but differs from those of other lepidopteran mt genomes because of the arrangement of tRNA genes. The tRNA region, which is located between the AT-rich region and nad2, is trnI/trnQ/trnM (IQM) in Thitarodes sp., rather than the trnM/trnI/trnQ (MIQ) of the Lepidoptera-specific rearrangement. All PCGs begin with the canonical start codons ATN or NTG, except for cox1, which starts with CGA. Most PCGs terminate with the typical stop codon TAA, although some have an incomplete stop codon (T). The 1473bp AT-rich region is located between the rrnS (12S rRNA) and trnI, which is the longest sequenced in a Thitarodes mt genome to date, containing nine 112bp copies and one partial copy of a 55bp sequence. The results derived from the phylogenetic tree, the genetic distances and the intergenic spacers of the mt genome show that the host insect of O. sinensis belongs to the Thitarodes, while Endoclita signifer and Napialus hunanensis form a relatively distinct lineage from Thitarodes. The sequence and full annotation of this moth mt genome will provide more molecular information about the Exoporia within the Lepidoptera, and the clarification of its phylogeny will improve the management of this insect resource and the conservation and sustainable use of this endangered medicinal species in China.

The complete mitochondrial genome of Trabala vishnou guttata (Lepidoptera: Lasiocampidae) and the related phylogenetic analyses

The bluish yellow lappet moth, Trabala vishnou guttata is an extraordinarily important pest in China. The complete mitochondrial genome is sequenced and determined firstly, which is based on traditional PCR amplification and primer walking methods with a length of 15,281 bp, including 13 protein-coding (PCG) genes, 22 transfer RNA (rRNA) genes, two ribosomal RNA (tRNA) genes, and an A + T-rich region. The gene order and orientation of the T. vishnou guttata mitogenome were identical to the other sequenced Lasiocampidae species. The overall nucleotide composition of T. vishnou guttata is A (40.27 %), T (40.59 %), C (11.58 %) and G (7.56 %), respectively. All the PCGs initiate with the three orthodox start codons ATN except for coxI with CGA start codon. Three PCGs (coxI, coxII and nad4) used incomplete stop codon T, while the other 10 PCGs terminate with complete stop codon TAA. All tRNA genes have a typical clover-leaf structure except for the absence of a dihydrouridine arm in trnS (AGN). The length of A + T-rich region is 383 bp. Phylogeny is established to reveal the genetic relationship between T. vishnou guttata and other lepidopteran species based on 13 PCGs nucleotide sequences of the sequenced species (32 taxa) by Maximum likelihood and Bayesian methods. Phylogenetic analyses presents that T. vishnou guttata and its closely related species (Dendrolimus taxa) are clustered on Lasiocampidae group. It is a sister clade relationship between Lasiocampidae and other families in Bombycoidea with a bootstrap value of 83 % and a posterior probability of 0.75. This study supports that Lasiocampidae may be independent from Bombycoidea.

The mitochondrial genome of Atrijuglans hetaohei Yang (Lepidoptera: Gelechioidea) and related phylogenetic analyses

Complete mitochondrial genome sequences are of great importance for better understanding the genome-level characteristics and phylogenetic relationships among related species. In this study, the complete mitochondrial genome of Atrijuglans hetaohei Yang is sequenced and analyzed, which is 15,379bp in length (GenBank: KT581634) and contains a typical set of 13 protein-coding genes, 22 tRNA genes, two rRNA genes and a non-coding region (control region). Except for cox1 gene that is initiated by CGA codon, all protein-coding genes start with ATN codons and end with the stop codon T, TA or TAA. All tRNAs have a typical clover-leaf secondary structure, except for trnS1, of which the DHU arm could not form a stable stem-loop structure. The secondary structure of rrnL and rrnS consists of 49 helices and 33 helices, respectively. Phylogenetic analyses of the complete mitochondrial genome sequences and of the amino acid sequences for 13 mitochondrial protein-coding genes among related species support the view that A. hetaohei is more closely related to the Gelechioidea than Yponomeutoidea. This result is consistent with a previous classification based on morphology.

The Complete Mitochondrial Genome of the Beet Webworm, Spoladea recurvalis (Lepidoptera: Crambidae) and Its Phylogenetic Implications

The complete mitochondrial genome (mitogenome) of the beet webworm, Spoladea recurvalis has been sequenced. The circular genome is 15,273 bp in size, encoding 13 protein-coding genes (PCGs), two rRNA genes, and 22 tRNA genes and containing a control region with gene order and orientation identical to that of other ditrysian lepidopteran mitogenomes. The nucleotide composition of the mitogenome shows a high A+T content of 80.9%, and the AT skewness is slightly negative (-0.023). All PCGs start with the typical ATN codons, except for COX1, which may start with the CGA codon. Nine of 13 PCGs have the common stop codon TAA; however, COX1, COX2 and ND5 utilize the T nucleotide and ND4 utilizes TA nucleotides as incomplete termination codons. All tRNAs genes are folded into the typical cloverleaf structure of mitochondrial tRNAs, except for the tRNA^Ser(AGY) gene, in which the DHU arm fails to form a stable stem-loop structure. A total of 157 bp intergenic spacers are scattered in 17 regions. The overlapping sequences are 42 bp in total and found in eight different locations. The 329 bp AT-rich region is comprised of non-repetitive sequences, including the motif ATAG, which is followed by a 14 bp poly-T stretch, a (AT₁₁ microsatellite-like repeat, which is adjacent to the motif ATTTA, and a 9 bp poly-A, which is immediately upstream from the tRNA^Met gene. Phylogenetic analysis, based on 13 PCGs and 13 PCGs+2 rRNAs using Bayesian inference and Maximum likelihood methods, show that the classification position of Pyraloidea is inconsistent with the traditional classification. Hesperioidea is placed within the Papilionoidea rather than as a sister group to it. The Pyraloidea is placed within the Macrolepidoptera with other superfamilies instead of the Papilionoidea.

The complete mitochondrial genome of Meriones meridianus (Rodentia: Cricetidae) and its phylogenetic analysis

Meriones meridianus belongs to the genus Meriones in Gerbillinae. Total length of complete mitochondrial genome of M. meridianus is 16,376 bp and the heavy strand contains 32.8% A, 13.1% G, 25.3% C and 28.8% T. Sequences of protein-coding genes are 11,341 bp in length, accounting for 69.25%, approximately. Results of phylogenetic analysis shown that M. meridianus and Meriones unguiculatus were clustered in a single branch. This conclusion would be an important data for relevant studies about the genus Meriones, and mitochondrial genome would be an important supplement for the gene pool of Rodentia. It would play a pivotal role in researches about phylogeography and proteomics involving M. meridianus as well.

The complete mitochondrial genome of Stylodipus telum (Rodentia: Dipodidae) and its phylogenetic analysis

Stylodipus telum belongs to the genus Stylodipus in the subfamily of Dipodinae. We got its complete genome first and it is 16,696 bp in length, the heavy strand contains 31.0% A, 13.8% G, 27.3% C, 27.9% T. Among them, protein-coding genes take up approximately 67.90% of the complete sequence. Trees constructed through phylogenetic analysis showed S. telum and Jaculus jaculus were clustered in one branch belonging to the family Dipodinae. This conclusion was identical to the former result by the methods of morphological taxonomy, and it would be convenient for further research on S. telum and other jerboa.

Morphological characters are compatible with mitogenomic data in resolving the phylogeny of nymphalid butterflies (lepidoptera: papilionoidea: nymphalidae)

Nymphalidae is the largest family of butterflies with their phylogenetic relationships not adequately approached to date. The mitochondrial genomes (mitogenomes) of 11 new nymphalid species were reported and a comparative mitogenomic analysis was conducted together with other 22 available nymphalid mitogenomes. A phylogenetic analysis of the 33 species from all 13 currently recognized nymphalid subfamilies was done based on the mitogenomic data set with three Lycaenidae species as the outgroups. The mitogenome comparison showed that the eleven new mitogenomes were similar with those of other butterflies in gene content and order. The reconstructed phylogenetic trees reveal that the nymphalids are made up of five major clades (the nymphaline, heliconiine, satyrine, danaine and libytheine clades), with sister relationship between subfamilies Cyrestinae and Biblidinae, and most likely between subfamilies Morphinae and Satyrinae. This whole mitogenome-based phylogeny is generally congruent with those of former studies based on nuclear-gene and mitogenomic analyses, but differs considerably from the result of morphological cladistic analysis, such as the basal position of Libytheinae in morpho-phylogeny is not confirmed in molecular studies. However, we found that the mitogenomic phylogeny established herein is compatible with selected morphological characters (including developmental and adult morpho-characters).

The mitochondrial genome of Dastarcus helophoroides (Coleoptera: Bothrideridae) and related phylogenetic analyses

The complete mitochondrial genome of Dastarcus helophoroides (Coleoptera: Bothrideridae) which consists of 13 PCGs, 22 tRNA genes, two rRNA genes and a non-coding region (D-loop), is sequenced for its nucleotide sequence of 15,878 bp (GenBank: KF811054.1). The genome has a typical gene order which is identical to other Coleoptera species. Except for COI gene generally starts with non-canonical initial codon, all protein-coding genes start with ATN codon and terminate with the stop codon TA(A) or TAG. The secondary structure of rrnL and rrnS consists of 48 helices (contains four newly proposed helices) and 35 helices (contains two newly proposed helices) respectively. All 22 tRNAs in D. helophoroides are predicted to fold into typical cloverleaf secondary structure, except trnS1 (AGN), in which the dihydrouracil arm (DHU arm) could not form stable stem-loop structure. Thirteen protein-coding genes (nucleotide dataset and nucleic acid dataset) of the available species (29 taxa) have been used to infer the phylogenetic relationships among these orders. Tenebrionoidea and Cucujoidea form a sister group, and D. helophoroides is classified into Cucujoidea (Bothrideridae). The study first research on the phylogenetic analyses involving to the D. helophoroides mitogenome, and the results strongly bolster the current morphology-based hypothesis.

Mitogenomic sequences effectively recover relationships within brush-footed butterflies (Lepidoptera: Nymphalidae)

BACKGROUND

Mitogenomic phylogenies have revealed well-supported relationships for many eukaryote groups. In the order Lepidoptera, 113 species mitogenomes had been sequenced (May 14, 2014). However, these data are restricted to ten of the forty-three recognised superfamilies, while it has been challenging to recover large numbers of mitogenomes due to the time and cost required for primer design and sequencing. Nuclear rather than mitochondrial genes have been preferred to reconstruct deep-level lepidopteran phylogenies, without seriously evaluating the potential of entire mitogenomes. Next-generation sequencing methods remove these limitations by providing efficiently massive amounts of sequence data. In the present study, we simultaneously obtained a large number of nymphalid butterfly mitogenomes to evaluate the utility of mitogenomic phylogenies by comparing reconstructions to the now quite well established phylogeny of Nymphalidae.

RESULTS

We newly obtained 30 nymphalid mitogenomes via pyrosequencing on the Roche 454 GS Junior system, and combined these sequences with publicly accessible data to provide a 70-taxa dataset covering 37 genes for a 15,495 bp alignment. Polymorphic sites were not homogeneously distributed across the gene. Two gene regions, nad6 and 3' end of nad5, were most variable, whereas the cox1 and 5' ends of rrnL were most conserved. Phylogenetic relationships inferred by two likelihood methods were congruent and strongly supported (>0.95 posterior probability; ML bootstrap >85%), across the majority of nodes for multiple partitioning strategies and substitution models. Bayes factor results showed that the most highly partitioned dataset is the preferred strategy among different partitioning schemes. The most striking phylogenetic findings were that the subfamily Danainae not Libytheinae was sister of the remaining brush-footed butterflies and that, within Limenitidini, the genus Athyma was clearly polyphyletic. None of the single-gene phylogenies recovered the highly supported topologies generated on the basis of the whole mitogenomic data.

CONCLUSIONS

Thirty mitogenomes were assembled with 89% completeness from the contigs of pyrosequencing-derived reads. Entire mitogenomes or higher-quality sequences could be obtained by increasing pyrosequencing read coverage or by additional Sanger sequencing. Our mitogenomic phylogenies provide robust nodal support at a range of levels, demonstrating that mitogenomes are both accurate and efficient molecular markers for inferring butterfly phylogeny.

The complete mitochondrial genome of the Byasa alcinous (Lepidoptera: Papilionidae: Papilioninae)

The complete mitochondrial genome (mitogenome) of Byasa alcinous (Lepidoptera: Papilionidae: Papilioninae) is a circular molecule of 15,266 bp in length, containing 37 typical insect mitochondrial genes: 13 protein coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and a non-coding AT-rich region. Its gene order and arrangement are identical to all other available butterfly mitogenomes. All PCGs start with a typical ATN initiation codon, except for COI, which is initiated by the CGA codon as observed in other butterfly species. Ten PCGs terminate in the complete stop codon TAA or TAG, whereas the COI, COII and ND4 genes end with single T. Ten intergenic spacers (73 bp in total), and 12 overlapping regions (28 bp in total) are dispersed throughout the whole genome. The non-coding AT-rich region is 405 bp long and contains some conserved structures similar to those found in other butterfly mitogenomes, such as the motif ATAGA followed by a 12-bp poly-T stretch and a microsatellite-like (AT)14 element preceded by the ATTTA motif. Additionally, a 11-bp poly-T sequences and a microsatellite-like (AT)7 repeated elements are detected in this region.

The complete mitochondrial genome of the Pazala timur (Lepidoptera: Papilionidae: Papilioninae)

The complete mitochondrial genome of Pazala timur (Lepidoptera: Papilionodae) is a circular molecule of 15,226 bp in length, containing 37 typical animal mitochondrial genes: 13 protein coding genes, 2 rRNA genes, 22 tRNA genes and a non-coding AT-rich region. Its gene order and arrangement are identical to all other available butterfly mitogenomes. All PCGs initiate with typical ATN codons, except for COI, which is initiated by the CGA codon. Ten PCGs use complete termination codon (TAA), whereas the COI, COII and ND5 genes end with single T. Twelve intergenic spacers (82 bp in total), and 11 overlapping regions (30 bp in total) are dispersed throughout the whole genome. The non-coding AT-rich region is 403 bp long and contains some conserved structures characteristic of the butterfly mitogenomes, such as the motif ATAGA followed by a 13-bp poly-T stretch and a microsatellite-like (AT)12 element preceded by the ATTTA motif.

Complete mitochondrial genome of Papilio syfanius (Lepidoptera: Papilionidae)

The complete mitochondrial genome (mitogenome) of the swallowtail butterfly Papilio syfanius has been completed. It is 15,359 bp, and contains the typical complement of 13 protein-coding (PCGs), 22 transfer RNA (tRNA) and 2 ribosomal RNA (rRNA) genes. Two A + T-rich regions are included in this mitogenome. The nucleotide composition is very similar to other insects, showing a high bias towards A + T, especially the control region (92.8%). Gene order in P. syfanius mitogenome is basically identical to that of the inferred ancestral insect genome, with the exception of translocations of trnM, which is common in genus Papilio.

Characterization of the complete mitochondrial genome of the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae)

The complete mitochondrial genome of the black cutworm Agrotis ipsilon (Lepidoptera: Noctuidae) was determined (GenBank accession No. KF163965). The length of this mitochondrial genome is 15,377 bp with an A + T content of 82.5%. There are 37 typical animal mitochondrial genes, that is, 13 protein-coding, 2 rRNA and 22 tRNA gene and an A + T-rich region. The tRNA gene trnM was rearranged to the upstream of the trnI-trnQ-trnM cluster compared with the pupative ancestral arrangement of insects. All protein-coding genes start with ATN start codon except for the gene cox1, which uses CGA as in other lepidopteran species. Ten protein-coding genes stop with termination codon TAA, whereas three protein-coding gene use incomplete stop codon T. The A + T-region is located between rrnS and trnM with a length of 332 bp and A + T content of 94.88%.

The first complete mitogenome for the superfamily Cossoidea of Lepidoptera: The seabuckthorn carpenter moth Eogystia hippophaecolus

We determined the first complete mitochondrial genome (mitogenome) for the superfamily Cossoidea of Lepidoptera from the seabuckthorn carpenter moth Eogystia hippophaecolus (GenBank accession No. KC831443). The length of this mitogenome is 15,431 bp with 37 typical animal mitochondrial genes and an A + T-rich region. The tRNA gene trnM was rearranged to the upstream of trnI-trnQ-trnM cluster compared with the pupative ancestral arrangement of insects. All protein-coding genes start with ATN start codon except for the gene cox1, which uses CGA as in other lepidopteran species. Eight protein-coding genes stop with termination codon TAA. One protein-coding gene uses incomplete stop codon TA and four use T. The A + T region is located between rrnS and trnM with a length of 317 bp and A + T content of 92.74%.

The complete mitogenome of the turnip moth Agrotis segetum (Lepidoptera: Noctuidae)

Abstract The complete mitochondrial genome (mitogenome) of the turnip moth Agrotis segetum (Lepidoptera: Noctuidae) was determined (GenBank accession No. KC894725). This is the first sequenced mitogenome from the subfamily Noctuinae of Noctuidae. The length of this mitogenome is 15,378 bp with a A+T content of 80.7%. There are 37 typical animal mitochondrial genes and a A+T-rich region. The tRNA gene trnM was the only rearranged gene compared with the pupative ancestral arrangement of insects. All protein-coding genes start with ATN start codon except for the gene cox1, which uses CGA as in other lepidopteran species. Ten protein-coding genes stop with termination codon TAA, whereas three protein-coding gene use incomplete stop codon T. The A+T-region is located between rrnS and trnM with a length of 332 bp and A+T content of 93.5%.

The complete mitochondrial genome of Solemya velum (Mollusca: Bivalvia) and its relationships with conchifera

Background

Bivalve mitochondrial genomes exhibit a wide array of uncommon features, like extensive gene rearrangements, large sizes, and unusual ways of inheritance. Species pertaining to the order Solemyida (subclass Opponobranchia) show many peculiar evolutionary adaptations, f.i. extensive symbiosis with chemoautotrophic bacteria. Despite Opponobranchia are central in bivalve phylogeny, being considered the sister group of all Autobranchia, a complete mitochondrial genome has not been sequenced yet.

Results

In this paper, we characterized the complete mitochondrial genome of the Atlantic awning clam Solemya velum: A-T content, gene arrangement and other features are more similar to putative ancestral mollusks than to other bivalves. Two supranumerary open reading frames are present in a large, otherwise unassigned, region, while the origin of replication could be located in a region upstream to the cox3 gene.

Conclusions

We show that S. velum mitogenome retains most of the ancestral conchiferan features, which is unusual among bivalve mollusks, and we discuss main peculiarities of this first example of an organellar genome coming from the subclass Opponobranchia. Mitochondrial genomes of Solemya (for bivalves) and Haliotis (for gastropods) seem to retain the original condition of mollusks, as most probably exemplified by Katharina.

Complete mitogenome of the Argyrogramma agnata (Lepidoptera: Noctuidae)

We determined the complete mitochondrial genome (mitogenome) of the silver looper moth Argyrogramma agnata (Lepidoptera: Noctuidae) (GenBank accession no. KC414791). The length of this mitogenome is 15,261 bp. All the 37 typical animal mitochondrial genes were found. The tRNA gene trnM was rearranged to the upstream of trnI-trnQ-trnM cluster compared with the pupative ancestral arrangement of insects. All protein-coding genes start with ATN start codon except for the gene cox1, which uses CGA as in other lepidopteran species. Nine protein-coding genes stop with termination codon TAA. One protein-coding gene uses incomplete stop codon TA and three use T. The A+T region is located between rrnS and trnM with a length of 334 bp.

Characterization of the mitochondrial genome of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) and phylogenetic analysis of advanced moths and butterflies

Here we determined the mitochondrial genome sequence of a notorious pest, the diamondback moth Plutella xylostella (Lepidoptera: Yponomeutoidea: Plutellidae). The mitochondrial genome contains 37 typical animal mitochondrial genes and an A+T-rich region. The gene arrangement is identical to that of other ditrysian lepidopteran mitochondrial genomes, but different from the ancestral gene arrangement in the non-ditrysian Hepialidae of Lepidoptera. The start codon of the cox1 gene is CGA, which is dissimilar to its homologs in most other insects. In Lepidoptera, cox1 and cox2 have low nucleotide diversities, while the nad6, nad2, and nad3 genes are highly variable. Phylogenetic analyses uncovered the reciprocal monophyly of Ditrysia, Apoditrysia, Obtectomera, and Macrolepidoptera, and the placement of the Hesperiidae within Papilionoidea. Our analyses suggest that the complete mitochondrial genome sequences are a promising marker toward fully resolving the phylogenetic relationships within Lepidoptera.

Complete Mitogenomes of Euploea mulciber (Nymphalidae: Danainae) and Libythea celtis (Nymphalidae: Libytheinae) and Their Phylogenetic Implications

The complete mitochondrial genome sequences of the two butterfly species Euploea mulciber (Lepidoptera: Nymphalidae: Danainae) and Libythea celtis (Lepidoptera: Nymphalidae: Libytheinae) were determined in this study, comprising 15,166 bp and 15,164 bp, respectively. The orientation and the gene order of the two mitogenomes are identical to those of most of the other lepidopteran species. All protein-coding genes of Euploea mulciber and Libythea celtis mitogenomes start with a typical ATN codon with the exception of COI gene which uses CGA as its initial codon. All tRNA genes possess the typical cloverleaf secondary structure except for tRNASer (AGN), which has a simple loop with the absence of the DHU stem. There are short microsatellite-like repeat regions, but no conspicuous macrorepeats scattered throughout the A + T-rich regions. Phylogenetic analysis among the available butterfly species suggests that Libythea celtis (Libytheinae) is closely related to Calinaga davidis (Calinaginae), indicating that the subfamily Libytheinae may not represent a basal lineage of the Nymphalidae as previously suggested, and that Euploea mulciber stands at the base of the nymphalid tree as a sister to all other nymphalids.

The complete mitochondrial genome of Cermatobius longicornis (Chilopoda: Lithobiomorpha: Henicopidae)

The first complete mitogenome sequence of Henicopidae is reported herein. The mitochondrial genome of Cermatobius longicornis (Lithobiomorpha: Henicopidae) is a circular molecule of 16,833 bp in length. It contains 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, a control region and a pseudo control region. The comparability of the last 396 bp between the control region and the pseudo control region is 70.3%. The alpha strand has the following nucleotide composition: A = 4858 (28.86%), T = 5813 (34.53%), C = 3184 (18.92%) and G = 2978 (17.69%). GC- and AT-skews for the alpha strand, which can reflect the base compositional differences between the two strands, are--0.03 and 0.09, respectively. The gene order of C. longicornis is identical to that of Limulus polyphemus, except for the extra pseudo control region.

Complete sequence of the mitochondrial genome of the Japanese buff-tip moth, Phalera flavescens (Lepidoptera: Notodontidae)

We sequenced the complete mitochondrial genome of Phalera flavescens. The mitogenome is 15,659 bp in length, including 13 protein-coding genes (atp6, atp8, cox1-3, nad1-6, nad4L, cob), two ribosomal RNAs (rrnS and rrnL), 22 transfer RNAs and an AT-rich region, a putative control region (D-loop). Gene order and orientation were found to be identical to those of other completely sequenced lepidopteran mitogenomes. All 13 protein-coding genes start with the common codon ATN, except for the cox1 gene, which uses CGA as the initial codon. Nine of the 13 protein-coding genes stop with codon TAA, while the cox1, cox2, nad5, and nad4 genes stop with the single nucleotide T. All tRNA genes can be folded into canonical cloverleaf secondary structure, except for trnS1, which loses the ''DHU'' arm. Six overlapping sequences totaling 20 bp (1-8 bp for each sequence) and 16 intergenic spacer sequences, totaling 276 bp (1-58 bp for each sequence) are scattered throughout the genome; the largest intergenic spacer is located between the trnQ and nad2 genes. A microsatellite-like structure (AT)(6)ACC(AT)(6) and 16-bp poly-T elements preceded by the ATTTA motif are present in the D-loop region. Additionally, unexpectedly, an extra 190-bp insertion, with unknown function, was found in the small subunit rRNA gene (rrnS); this gene is the longest known (1020 bp) among all of the Lepidoptera.

Interspecific variation in mitochondrial serine transfer RNA (UCN) in Euptychiina butterflies (Lepidoptera: Satyrinae): structure and alignment

The nucleotide variation and structural patterns of mitochondrial RNA molecule have been proposed as useful tools in molecular systematics; however, their usefulness is always subject to a proper assessment of homology in the sequence alignment. The present study describes the secondary structure of mitochondrial tRNA for the amino acid serine (UCN) on 13 Euptychiina species and the evaluation of its potential use for evolutionary studies in this group of butterflies. The secondary structure of tRNAs showed variation among the included species except between Hermeuptychia sp1 and sp2. Variation was concentrated in the ribotimidina-pseudouridine-cystosine (TψC), dihydrouridine (DHU) and variable loops and in the DHU and TψC arms. These results suggest this region as a potential marker useful for taxonomic differentiation of species in this group and also confirm the importance of including information from the secondary structure of tRNA to optimize the alignments.

Complete mitogenome of the Lesser Purple Emperor Apatura ilia (Lepidoptera: Nymphalidae: Apaturinae) and comparison with other nymphalid butterflies

The complete mitochondrial genome of Apatura ilia (GenBank accession no. JF437925) was determined as a circular DNA molecule of 15 242 bp, with common genes of 13 putative proteins, 2 rRNAs, and 22 tRNAs and of the same gene arrangement as in other sequenced lepidopterans. All protein-coding genes had the typical start codon ATN, except for the COI's using CGA as its start codon as previously demonstrated in other lepidopteran species. The comparison of the nucleotide sequences of the A. ilia mitogenome with ten other Nymphalidae species showed nearly identical gene orientation and arrangement, with only a few alterations in non-coding fragments. The nucleotide composition and codon frequency all fell into the range estimated for the order Lepidoptera. The A. ilia mitochondrial genome had the canonical set of 22 tRNA genes folded in the typical cloverleaf structure, with an unique exception of tRNA(Ser) (AGN). The mitochondrial genes from A. ilia were overlapped in a total of 33 bp at 9 locations, as well as interleaved with a total of 155 bp intergenic spacers, spread over 12 regions with the size ranging from 1 to 49 bp. Furthermore, the spacer between ND6 and Cyt b harbored a microsatellite-like repeat (TA)(23) not found in other completely sequenced nymphalid genomes. The 403 bp AT-rich region harbored two conserved motifs (ATAGA, ATTTA), a 21 bp polyT stretch, a 10 bp poly-A region, along with two microsatellite-like repeats ( (TA)(10) and (TA)(7)), as detected in other nymphalid butterflies.

The complete mitochondrial genome of Leucoptera malifoliella Costa (Lepidoptera: Lyonetiidae)

The mitochondrial genome (mitogenome) of Leucoptera malifoliella (=L. scitella) (Lepidoptera: Lyonetiidae) was sequenced. The size was 15,646 bp with gene content and order the same as those of other lepidopterans. The nucleotide composition of L. malifoliella mitogenome is highly A+T biased (82.57%), ranked just below Coreana raphaelis (82.66%) (Lepidoptera: Lycaenidae). All protein-coding genes (PCGs) start with the typical ATN codon except for the cox1 gene, which uses CGA as the initiation codon. Nine PCGs have the common stop codon TAA, four PCGs have the common stop codon T as incomplete stop codons, and nad4l and nad6 have TAG as the stop codon. Cloverleaf secondary structures were inferred for 22 tRNA genes, but trnS1(AGN) was found to lack the DHU stem. The secondary structure of rrnL and rrnS is generally similar to other lepidopterans but with some minor differences. The A+T-rich region includes the motif ATAGA, but the poly (T) stretch is replaced by a stem-loop structure, which may have a similar function to the poly (T) stretch. Finally, there are three long repeat (154 bp) sequences followed by one short repeat (56 bp) with four (TA)(n) intervals, and a 10-bp poly-A is present upstream of trnM. Phylogenetic analysis shows that the position of Yponomeutoidea, as represented by L. malifoliella, is the same as traditional classifications. Yponomeutoidea is the sister to the other lepidopteran superfamilies covered in the present study.

The complete mitochondrial genomes of two ghost moths, Thitarodes renzhiensis and Thitarodes yunnanensis: the ancestral gene arrangement in Lepidoptera

Background

Lepidoptera encompasses more than 160,000 described species that have been classified into 45–48 superfamilies. The previously determined Lepidoptera mitochondrial genomes (mitogenomes) are limited to six superfamilies of the lineage Ditrysia. Compared with the ancestral insect gene order, these mitogenomes all contain a tRNA rearrangement. To gain new insights into Lepidoptera mitogenome evolution, we sequenced the mitogenomes of two ghost moths that belong to the non-ditrysian lineage Hepialoidea and conducted a comparative mitogenomic analysis across Lepidoptera.

Results

The mitogenomes of Thitarodes renzhiensis and T. yunnanensis are 16,173 bp and 15,816 bp long with an A + T content of 81.28 % and 82.34 %, respectively. Both mitogenomes include 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and the A + T-rich region. Different tandem repeats in the A + T-rich region mainly account for the size difference between the two mitogenomes. All the protein-coding genes start with typical mitochondrial initiation codons, except for cox1 (CGA) and nad1 (TTG) in both mitogenomes. The anticodon of trnS(AGN) in T. renzhiensis and T. yunnanensis is UCU instead of the mostly used GCU in other sequenced Lepidoptera mitogenomes. The 1,584-bp sequence from rrnS to nad2 was also determined for an unspecified ghost moth (Thitarodes sp.), which has no repetitive sequence in the A + T-rich region. All three Thitarodes species possess the ancestral gene order with trnI-trnQ-trnM located between the A + T-rich region and nad2, which is different from the gene order trnM-trnI-trnQ in all previously sequenced Lepidoptera species. The formerly identified conserved elements of Lepidoptera mitogenomes (i.e. the motif ‘ATAGA’ and poly-T stretch in the A + T-rich region and the long intergenic spacer upstream of nad2) are absent in the Thitarodes mitogenomes.

Conclusion

The mitogenomes of T. renzhiensis and T. yunnanensis exhibit unusual features compared with the previously determined Lepidoptera mitogenomes. Their ancestral gene order indicates that the tRNA rearrangement event(s) likely occurred after Hepialoidea diverged from other lepidopteran lineages. Characterization of the two ghost moth mitogenomes has enriched our knowledge of Lepidoptera mitogenomes and contributed to our understanding of the mechanisms underlying mitogenome evolution, especially gene rearrangements.

Characterization of the complete mitochondrial genomes of Cnaphalocrocis medinalis and Chilo suppressalis (Lepidoptera: Pyralidae)

The complete mitochondrial genomes (mitogenomes) of Cnaphalocrocis medinalis and Chilo suppressalis (Lepidoptera: Pyralidae) were determined and analyzed. The circular genomes were 15,388 bp long for C. medinalis and 15,395 bp long for C. suppressalis. Both mitogenomes contained 37 genes, with gene order similar to that of other lepidopterans. Notably, 12 protein-coding genes (PCGs) utilized the standard ATN, but the cox1 gene used CGA as the initiation codon; the cox1, cox2, and nad4 genes in the two mitogenomes had the truncated termination codons T, T, and TA, respectively, but the nad5 gene was found to use T as the termination codon only in the C. medinalis mitogenome. Additionally, the codon distribution and Relative Synonymous Codon Usage of the 13 PCGs in the C. medinalis mitogenome were very different from those in other pyralid moth mitogenomes. Most of the tRNA genes had typical cloverleaf secondary structures. However, the dihydrouridine (DHU) arm of the trnS1(AGN) gene did not form a stable stem-loop structure. Forty-nine helices in six domains, and 33 helices in three domains were present in the secondary structures of the rrnL and rrnS genes of the two mitogenomes, respectively. There were four major intergenic spacers, except for the A+T-rich region, spanning at least 12 bp in the two mitogenomes. The A+T-rich region contained an 'ATAGT(A)'-like motif followed by a poly-T stretch in the two mitogenomes. In addition, there were a potential stem-loop structure, a duplicated 25-bp repeat element, and a microsatellite '(TA)₁₃' observed in the A+T-rich region of the C. medinalis mitogenome. A poly-T motif, a duplicated 31-bp repeat element, and a 19-bp triplication were found in the C. suppressalis mitogenome. However, there are many differences in the A+T-rich regions between the C. suppressalis mitogenome sequence in the present study and previous reports. Finally, the phylogenetic relationships of these insects were reconstructed based on amino acid sequences of mitochondrial 13 PCGs using Bayesian inference and maximum likelihood methods. These molecular-based phylogenies support the traditional morphologically based view of relationships within the Pyralidae.

The Complete Mitochondrial Genome of Ctenoptilum vasava (Lepidoptera: Hesperiidae: Pyrginae) and Its Phylogenetic Implication

We here report the first complete mitochondrial (mt) genome of a skipper, Ctenoptilum vasava Moore, 1865 (Lepidoptera: Hesperiidae: Pyrginae). The mt genome of the skipper is a circular molecule of 15,468 bp, containing 2 ribosomal RNA genes, 24 putative transfer RNA (tRNA), genes including an extra copy of trnS (AGN) and a tRNA-like insertion trnL (UUR), 13 protein-coding genes and an AT-rich region. All protein-coding genes (PCGs) are initiated by ATN codons and terminated by the typical stop codon TAA or TAG, except for COII which ends with a single T. The intergenic spacer sequence between trnS (AGN) and ND1 genes also contains the ATACTAA motif. The AT-rich region of 429 bp is comprised of nonrepetitive sequences, including the motif ATAGA followed by an 19 bp poly-T stretch, a microsatellite-like (AT)(3) (TA)(9) element next to the ATTTA motif, an 11 bp poly-A adjacent to tRNAs. Phylogenetic analyses (ML and BI methods) showed that Papilionoidea is not a natural group, and Hesperioidea is placed within the Papilionoidea as a sister to ((Pieridae + Lycaenidae) + Nymphalidae) while Papilionoidae is paraphyletic to Hesperioidea. This result is remarkably different from the traditional view where Papilionoidea and Hesperioidea are considered as two distinct superfamilies.

The mitochondrial genome of Bacillus stick insects (Phasmatodea) and the phylogeny of orthopteroid insects

The Order Phasmatodea (stick and leaf insects) includes many well-known species of cryptic phytophagous insects. In this work, we sequenced the almost complete mitochondrial genomes of two stick insect species of the genus Bacillus. Phasmatodea pertain to the Polyneoptera, and represent one of the major clades of heterometabolous insects. Orthopteroid insect lineages arose through rapid evolutionary radiation events, which likely blurred the phylogenetic reconstructions obtained so far; we therefore performed a phylogenetic analysis to resolve and date all major splits of orthopteroid phylogeny, including the relationships between Phasmatodea and other polyneopterans. We explored several molecular models, with special reference to data partitioning, to correctly detect any phylogenetic signal lying in rough data. Phylogenetic Informativeness analysis showed that the maximum resolving power on the orthopteroid mtDNA dataset is expected for the Upper Cretaceous, about 80millionyears ago (Mya), but at least 70% of the maximum informativeness is also expected for the 150-200 Mya timespan, which makes mtDNA a suitable marker to study orthopteroid splits. A complete chronological calibration has also been computed following a Penalized Likelihood method. In summary, our analysis confirmed the monophyly of Phasmatodea, Dictyoptera and Orthoptera, and retrieved Mantophasmatodea as sister group of Phasmatodea. The origin of orthopteroid insects was also estimated to be in the Middle Triassic, while the order Phasmatodea seems to appear in the Upper Jurassic. The obtained results evidenced that mtDNA is a suitable marker to unravel the ancient splits leading to the orthopteroid orders, given a proper methodological approach.

Geographic distribution of phylogenetically-distinct legume pod borer, Maruca vitrata (Lepidoptera: Pyraloidea: Crambidae)

Maruca vitrata Fabricius is a pantropical lepidopteran pest of legumes. Phylogenetic analysis of a mitochondrial cytochrome c oxidase-I gene (cox1) fragment indicates that three Maruca sp. mitochondrial lineages have unique geographic distributions [lineages 1 and 2: Australia, Taiwan, and West Africa (Niger, Nigeria, and Burkina Faso), and lineage 3: Puerto Rico]. The haplotype (T30, T114) is specific to lineages 1&2 and was assayed by NsiI and SacI polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) within population samples; it was not observed in the Puerto Rican samples, but was nearly fixed among samples from West Africa, Australia and Taiwan (85.5-100%). Re-sequencing and phylogenetic analyses of PCR-RFLP defined cox1 haplotypes indicate that nucleotide diversity is highest among samples from West Africa. Phylogenetic reconstruction based upon ribosomal DNA (rDNA) internal transcribed spacer-2 (ITS-2) sequences provided additional evidence for three Maruca sp. clades. These data suggest that multiple unique Maruca species or subspecies are present worldwide, which has implications for the management of this pest species-complex.