Annual Research & Review in Biology

Lepidoptera, as one of the diverse insect orders, play a very critical role in ecological and economic perspectives, yet it remains taxonomically challenging due to morphological convergence, cryptic diversity, and incomplete classification frameworks. Over the last two decades, DNA barcoding, primarily targeting the mitochondrial COI gene, has revolutionised species identification and biodiversity assessment. This mini-review summarises certain key advances in Lepidoptera barcoding across four thematic areas: large-scale biodiversity surveys; pest species diagnostics; cryptic species discovery; and future conservation planning. Case studies from tropical forests, island ecosystems, and high-altitude plateau ecozones have illustrated the precision and practical value of this method. However, gaps persist, including uneven representation in global databases, taxonomic instability in certain groups, and methodological inconsistencies across the whole taxonomic spectrum. We have discussed integrative approaches towards merging DNA barcoding with morphological, genomic, and ecological data, and outlined priorities for expanding coverage, improving accuracy, and embedding molecular identification into conservation policy. By harbouring both its achievements and limitations, this review has positioned “DNA barcoding” as a milestone technology for Lepidoptera systematics and applied biodiversity management in various important ecozones of Earth.