The atlas of mitochondrial genetic diversity for Western Palaearctic butterflies

Motivation: Butterflies represent a model in biology and a flagship group for invertebrate conservation. We provide four new resources for the Western Palaearctic butterflies: (1) an updated checklist comprising 552 species; (2) a curated dataset of 32,126 mitochondrial cytochrome c oxidase subunit I (COI) sequences for 532 species, including a de novo reference library for the Maghreb (Morocco, northern Algeria and Tunisia) and Macaronesia (Azores, Madeira and Canary Islands); (3) seven indexes of intraspecific genetic variation (IGV): observed and expected number of haplotypes, haplotype and nucleotide diversity, two fixation indexes and maximum p-distance; and (4) species-level maps illustrating the distribution of COI variability and haplotype networks. The updated checklist will be fundamental for any application dealing with butterfly diversity in the Western Palaearctic. The IGV indexes provide measures for genetic polymorphism and spatial structure and represent proxies for dispersal capacity. These resources will facilitate comparative studies of macrogenetics, foster integrative taxonomy and aid conservation strategies. Main types of variables contained: A complete species checklist in table format, 32,126 mitochondrial DNA barcodes provided with metadata (species membership, WGS84 coordinates and sequence length) and a book in PDF format, including the IGV atlas and indexes, are provided. Spatial location and grain: The checklist encompasses Europe up to the Urals in the east, north Macaronesia (the Azores, Madeira and the Canary Islands) and the Maghreb (Morocco, northern Algeria and Tunisia). COI sequences have been retained in the geographical interval of −31.3 to 67.5° of longitude and 27.5–71.2° of latitude. Time period and grain: COI sequences originate from studies published between 1998 and 2022 and from de novo sequencing of 2541 specimens done between 2007 and 2022. Major taxa and level of measurement: Butterflies (Lepidoptera: Papilionoidea), analysed from individual to species level. Software format: Data and functions to manage the dataset are provided in the iodatabase R package (https://github.com/leondap/iodatabase) and in Dryad (https://doi.org/10.5061/dryad.9w0vt4bjj).