Characterisation and phylogenetic analysis of the complete mitogenome of the edible insect bamboo worm Omphisa fuscidentalis in Yunnan Province, China

Abstract

The bamboo worm Omphisa fuscidentalis is a kind of popular edible insect in Indochina Peninsula, however, the genus affiliation of this insect is controversial. Previous taxonomic studies from China and Thailand using limited morphology and single mitochondrial gene evidence indicated that, those samples distributed in different areas from Asia could belong to different species in different genera. To understand its taxonomic status and phylogenetic relationship with related taxa, we first sequenced and characterised the complete mitochondrial genome (mitogenome) of the moth O. fuscidentalis’ mitogenome is 15,347 bp in size, and containing 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs, and a control region. Further, 23 of the 37 genes are encoded by the J-strand while 14 are encoded by the N-strand. Most of PCGs are initiated by ATN codons, but 3 of the 13 PCGs harboured the incomplete termination codon by T. In the gene order of O. fuscidentalis, the ancestor of Lepidoptera sequence trnI-trnQ-trnM morphed into trnM-trnI-trnQ, as observed in other Pyraloidea species. A phylogenetic tree was then constructed based on the nucleotide sequences of mitochondrial 13 PCGs from 41 Pyraloidea species and two Tortricoidea species (outgroups) using Bayesian inference and maximum likelihood, which determined that O. fuscidentalis belongs to Crambidae. Accordingly, the bamboo worm does not belong to the genus Chilo in the subfamily Crambinae, or to the subfamily Spilomelinae. This study provides fundamental data to clarify the taxonomic status and better understand the biology of this edible insect.