The complete mitochondrial genome (mitogenome) ofLeucoma salicis(Lepidoptera: Lymantriidae) was sequenced and annotated. It is a circular molecule of 15,334 bp, containing the 37 genes usually present in insect mitogenomes. All protein-coding genes (PCGs) are initiated by ATN codons, other thancox1, which is initiated by CGA. Three of the 13 PCGs had an incomplete termination codon, T or TA, while the others terminated with TAA. The relative synonymous codon usage of the 13 protein-coding genes (PCGs) was consistent with those of published lepidopteran sequences. All tRNA genes had typical clover-leaf secondary structures, except for thetRNA^Ser(AGN), in which the dihydrouridine (DHU) arm could not form a stable stem-loop structure. The A + T-rich region of 325 bp had several distinctive features, including the motif ‘ATAGA’ followed by an 18 bp poly-T stretch, a microsatellite-like (AT)₇element, and an 11-bp poly-A present immediately upstream oftRNA^Met. Relationships among 32 insect species were determined using Maximum Likelihood (ML), Neighbor Joining (NJ) and Bayesian Inference (BI) phylogenetic methods. These analyses confirm thatL. salicisbelongs to the Lymantriidae; and that Lymantriidae is a member of Noctuoidea, and is a sister taxon to Erebidae, Nolidae and Noctuidae, most closely related to Erebidae.

The complete mitochondrial genome (mitogenome) of Plutella xylostella (Lepidoptera: Plutellidae) was determined (GenBank accession No. KM023645). The length of this mitogenome is 16,014 bp with 13 protein-coding genes (PCGs), 2 rRNA genes, 22 tRNA genes and an A + T-rich region. It presents the typical gene organization and order for completely sequenced lepidopteran mitogenomes. The nucleotide composition of the genome is highly A + T biased, accounting for 81.48%, with a slightly positive AT skewness (0.005). All PCGs are initiated by typical ATN codons, except for the gene cox1, which uses CGA as its start codon. Some PCGs harbor TA (nad5) or incomplete termination codon T (cox1, cox2, nad2 and nad4), while others use TAA as their termination codons. The A + T-rich region is located between rrnS and trnM with a length of 888 bp.

The complete mitochondrial genome (mitogenome) of Cerura menciana (Lepidoptera: Notodontidae) was sequenced and analyzed in this study. The mitogenome is a circular molecule of 15,369 bp, containing 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes and a A+T-rich region. The positive AT skew (0.031) indicated that more As than Ts were present. All PCGs were initiated by ATN codons, except for the cytochrome c oxidase subunit 1 (cox1) gene, which was initiated by CAG. Two of the 13 PCGs contained the incomplete termination codon T or TA, while the others were terminated with the stop codon TAA. The A+T-rich region was 372 bp in length and consisted of an ‘ATAGA’ motif followed by an 18 bp poly-T stretch, a microsatellite-like (AT)₈ and a poly-A element upstream of the trnM gene. Results examining codon usage indicated that Asn, Ile, Leu2, Lys, Tyr and Phe were the six most frequently occurring amino acids, while Cys was the rarest. Phylogenetic relationships, analyzed based on the nucleotide sequences of the 13 PCGs from other insect mitogenomes, confirmed that C. menciana belongs to the Notodontidae family.

In the present study, the complete sequence of the mitochondrial genome (mitogenome) of Daphnis nerii (Lepidoptera: Sphingidae) is described. The mitogenome (15,247 bp) of D.nerii encodes13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and an adenine (A) + thymine (T)-rich region. Its gene complement and order is similar to that of other sequenced lepidopterans. The 12 PCGs initiated by ATN codons except for cytochrome c oxidase subunit 1 (cox1) gene that is seemingly initiated by the CGA codon as documented in other insect mitogenomes. Four of the 13 PCGs have the incomplete termination codon T, while the remainder terminated with the canonical stop codon. This mitogenome has six major intergenic spacers, with the exception of A+T-rich region, spanning at least 10 bp. The A+T-rich region is 351 bp long, and contains some conserved regions, including ‘ATAGA’ motif followed by a 17 bp poly-T stretch, a microsatellite-like element (AT)₉ and also a poly-A element. Phylogenetic analyses based on 13 PCGs using maximum likelihood (ML) and Bayesian inference (BI) revealed that D. nerii resides in the Sphingidae family.