Performance of DNA barcodes for informing the subspecies controversy in North American populations of Callophrys gryneus (Hübner, [1819]) (Lepidoptera: Lycaenidae)

Abstract

Analysis of genetic divergence in published mitochondrial DNA barcodes from ‘juniper’ and ‘cedar’ hairstreaks, Callophrys gryneus (Hübner) and Callophrys muiri (Hy. Edwards), together with a comparison of phenotypic differences in populations from North America, have been used to address the long-standing controversy regarding subspecies and species assignments in this confusing group of hairstreaks. The most recent view holds that C. gryneus is a single polytypic species comprising 11 nominal subspecies and that C. muiri from California is a valid species. An alternative view subdivides C. gryneus into three nominal species, C. gryneus (s.s.), Callophrys siva and Callophrys nelsoni, each with several named subspecies, and retains C. muiri as a full species. Haplotype networks, phylogenetic analysis and analysis of molecular variance of barcodes provided evidence supporting the subspecies scenario. However, barcodes from closely related congeners of C. gryneus (s.l.) revealed pairwise genetic divergences that would also support elevating three subspecies (C. g. castalis, C. g. siva and C. g. nelsoni) to full species. The barcode data also raise the question of whether C. muiri warrants full species status. Larval host plant preference as a possible driver of genetic differentiation in western populations of this group is also discussed briefly.