Abstract: Motivation
Butterflies represent a model in biology and a flagship group for invertebrate conservation. We provide four new resources for the Western-Palearctic butterflies: 1) An updated checklist comprising 552 species; 2) a curated dataset of 32,129 mitochondrial COI sequences for 532 species, including a de novo reference library for the Maghreb (Morocco and 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; 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 Western Palearctic. IGV indexes provide measures for genetic polymorphism and spatial structure and represent proxies for dispersal capacity. These resources will facilitate comparative studies of macrogenetics, will foster integrative taxonomy, and will aid conservation strategies.

Main types of variables contained
A complete species checklist in table format, 32,129 mitochondrial DNA-barcodes provided with metadata (species membership, WGS84 coordinates, sequence length), and a book in PDF format including the IGV atlas and indexes.

Spatial location and grain
The checklist encompasses Europe up to Urals in the east, north Macaronesia (Azores, Madeira and Canary Islands), as well as the Maghreb (Morocco and northern Algeria and Tunisia). DNA-barcodes have been retained in the geographic interval of -31.3–67.5 degrees of longitude and 27.5–71.2 degrees of latitude.

Time period and grain
DNA-barcodes originate from studies published between 1998-2022 and from de novo sequencing of 2,608 specimens done between 2007-2022.

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

The dataset of the Atlas of mitochondrial genetic diversity for Western Palearctic butterflies (COI sequences and metadata) is available in the iodatabase R package available at https://github.com/leondap/iodatabase.

Here the R script with a few supplementaty files is available in order to replicate the figures composing the Atlas