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.