Chinese oak silkworm, Antheraea pernyi Guérin-Méneville 1855 (Lepidoptera: Saturniidae), is a traditional edible insect in China and is considered the edible insect with the highest potential. Information on the mitochondrial genome (mitogenome) of the first modern improved strain of this silkworm, Qinghuang_1, is currently unavailable. Here, we determine the mitogenome of Qinghuang_1 by long PCR amplification followed by Illumina sequencing and then compare the resulting mitogenome with the five available mitogenomes of this species. The mitogenome of Qinghuang_1 is 15,573 bp in length and exhibits an identical gene organisation to known A. pernyi mitogenomes. The base A content of this mitogenome is higher than those of the other four strains but lower than that of the wild type. Sequence comparisons identified 200 single-nucleotide variants (1.28%) and 32 amino acid changes among the five inbred strains, indicating a considerable degree of nucleotide diversity in the mitogenomes of A. pernyi germplasm resources. The 3’ end of ND1 was identified as a hotspot in the A. pernyi mitogenome. Ka/Ks analysis indicated that all protein-coding genes evolved under negative selection except for ND5, which presented values larger than 1, suggesting that positive selection may act on this gene. The phylogenetic analyses confirmed the basal position of Qinghuang_1 among the inbred strains of A. pernyi. Our results indicated that the mitogenome is helpful for understanding the intraspecific phylogenetic relationships of A. pernyi and for its genetic improvement.

Samia ricini (Wm. Jones) and Samia cynthia (Drury) (Lepidoptera: Saturniidae) have been used as traditional sources of food as well as silk-producing insects. However, the phylogenetic relationship between the two silkworms remains to be addressed. In this study, the mitochondrial cytochrome c oxidase subunit 1 (COI) gene sequences corresponding to DNA barcodes from 13 Samia species were analysed, and a DNA barcode-based phylogenetic framework for these Samia species was provided. Phylogenetic analysis showed that multiple individuals of a species could be clustered together. Our analysis revealed a close relationship among Samia yayukae Paukstadt, Peigler and Paukstadt, Samia abrerai Naumann and Peigler, Samia kohlli Naumann and Peigler, Samia naessigi Naumann and Peigler, Samia naumanni Paukstadt, Peigler and Paukstadt, and Samia kalimantanensis Paukstadt and Paukstadt. The mixed clustering relationship and low Kimura-2-parameter (K2P) genetic distance (0.006) between individuals of S. ricini and Samia canningi (Hutton) indicated that the cultivated silkworm S. ricini was derived from the non-cultivated silkworm S. canningi. The remote phylogenetic relationship and high K2P genetic distance (0.039) indicated that S. ricini and S. cynthia are distinct species, thus providing solid molecular evidence that they had entirely independent origins. The relationships between S. kalimantanensis and S. naumanni and between S. cynthia and Samia wangi Naumann and Peigler, as well as the potential cryptic species within S. abrerai were also discussed. This is the first study to assess the DNA barcodes of the genus Samia, which supplements the knowledge of species identification and provides the first molecular phylogenetic framework for Samia species.