Structural characteristics and phylogenetic analysis of the mitochondrial genome of the rice leafroller, Cnaphalocrocis medinalis (Lepidoptera: Crambidae).

The rice leafroller, Cnaphalocrocis medinalis, is one of the most important pests on rice and possesses striking flight ability. We have determined the nucleotide sequence of the 15,377 bp of a C. medinalis mitochondrial genome (mtDNA). The mtDNA encodes 37 genes and shows a unique lepidopteran CR-M-I-Q arrangement. Three possible substructures were detected in C. medinalis and some other lepidopteran insects' control region. The findings might be relevant to the regulation of mtDNA replication and transcription. Phylogenetic relationships were reconstructed among 19 families in Lepidoptera so far. Cnaphalocrocis medinalis forms a reciprocal monophyletic group with Ostrinia in clade Crambidae instead of Pyralidae. The topology between Papilionoidea and other superfamilies showed an apparent contradiction with traditional Lepidopteran classification. As a well-known migratory insect, the molecular information contained in C. medinalis mtDNA may provide a further insight into the evolution of mitochondria genes and insect species, and may help to better understanding the energy metabolism of invertebrates.