Abstract
The butterfly genus Acytolepis (Lepidoptera: Lycaenidae: Polyommatinae) is widely distributed in the Indomalayan and Australasian realms. However, no complete mitochondrial genome has been reported for this genus, leaving its mitogenomic characteristics and evolutionary patterns unclear. In this study, we sequenced and characterized the first complete mitogenome of Acytolepis puspa, the type species of the genus. The circular double-stranded mitogenome is 15,511 bp in length and comprises 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and one A + T-rich control region, exhibiting a typical gene content and organization conserved in Lepidoptera. Comparative analyses of Polyommatinae mitogenomes revealed pronounced heterogeneity in evolutionary rates among PCGs, with ND6 and ND3 showing relatively high nucleotide diversity, whereas COX1 was the most conserved gene. Selection pressure analyses indicated that all PCGs are evolving under purifying selection, with ATP8 and ND6 exhibiting relatively relaxed selective constraints compared to other genes. Phylogenetic analyses based on concatenated mitochondrial PCGs using both Maximum likelihood (ML) and Bayesian inference (BI) methods produced identical and well-supported topologies, recovering A. puspa as the sister taxon to Celastrina species within Polyommatinae. Overall, this study provides the first mitogenomic resource for Acytolepis, enriches mitochondrial molecular markers for lycaenid butterflies, and contributes new insights into mitogenome evolution and phylogenetic relationships within Polyommatinae.