Global geographical and latitudinal variation in butterfly species richness captured through a comprehensive country‐level occurrence database.

Motivation: Insects provide vital ecological functions and account for over half of all described species. An at least basic understanding of their geographical distributions is key for addressing a range of central ecological and evolutionary questions and to inform conservation. However, even for popular groups, such as butterflies, the knowledge of species' distributions at global scale remains highly incomplete. To address this information gap, we present a data product of comprehensive country‐level occurrences for the 19,327 accepted species of extant butterflies. This compilation is based on a quality‐controlled combination of 165 literature sources and publicly available occurrence records from Global Biodiversity Information Facility (GBIF), harmonized to a global master taxonomy, and constitutes 159,659 (87,506 unique) species–country combinations. We developed a protocol for the integration of country‐level information from literature into the process of cleaning/validating species point occurrence records that facilitates dynamic updates of these country‐level checklist data. Such occurrence records are available for less than 54% of the species, with an apparent bias towards temperate regions and taxa. We use this combined database for a global assessment of the geographical variation in the diversity of butterflies, including an analysis of latitudinal gradients in the species richness—the first undertaken at this higher resolution. Country‐level richness decreases from the equator to the poles, both with and without control for country sizes. The presented data and analyses highlight the potential of leveraging multiple types of distribution information, particularly for taxa with limited data and their incorporation in ecological and conservation analysis. Our database and associated workflows provide a basis for an improved biogeographical understanding and conservation of insect biodiversity. Main types of variables contained: Country‐level occurrences and their sources. Spatial location and grain: Global, 256 countries. Time period and grain: 1861 to 2021. Major taxa and level of measurement: 19,191 accepted species of extant butterflies. Software format:.csv,.shp. [ABSTRACT FROM AUTHOR]