First Record of the Complete Mitochondrial Genome for the Genus Borbo (Lepidoptera, Hesperiidae): Characterization and Comparative Genomic Analysis

Abstract

Butterflies of the genus Borbo are mainly distributed in the Oriental and Australian regions and are considered pests of important crops. However, no mitochondrial genomes have been reported for this genus until now, leaving the evolutionary characteristics and differentiation patterns of their mitogenomes unclear. In this study, we present the first complete mitochondrial genome sequence of the rice swift, Borbo cinnara. The circular double-stranded mitogenome was 15,508 bp in length, comprising 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and 1 non-coding control region (CR). Among the mitogenomes of Hesperiinae, the ND3 gene was found to be the most variable PCG, while COX1 was the most conserved. Selection pressure analysis revealed that ND3 was under relaxed purifying selection, whereas COX1 was subjected to strong purifying selection. Phylogenetic trees reconstructed using both the Bayesian inference (BI) and maximum likelihood (ML) methods yielded robust and identical topologies, confirming the sister relationship between B. cinnara and Pelopidas mathias at the mitogenome level. Methodologically, this research enriches novel molecular markers for the species identification of butterflies and enhances our understanding of mitogenomic evolution in Lepidoptera.