The first annotated checklist of the bees of Colombia reveals an overlooked diversity and areas with major data deficiencies

Background Most existing knowledge about bee biodiversity comes from temperate regions, where diversity is presumed highest—yet substantial data gaps across the tropics confound this pattern. Checklists are critical for documenting species presence, identifying knowledge gaps, and guiding conservation. We present the first comprehensive bee checklist for Colombia, a country in tropical northern South America that serves as a key biogeographic bridge between Central and South America. We hypothesize that Colombia’s complex topography, its position at the intersection of multiple biogeographic regions, and its partial Gondwanan origin contribute to exceptionally high bee diversity and endemism. Methods We built a network of local entomological collections to compile specimen data ( n = 62,158), combined with occurrence records from public datasets ( n = 25,520) and species records reported in the taxonomic literature ( n = 297). Our objectives were to: (1) synthesize the first bee species checklist for Colombia and their genus-level biological traits (ecoregional distribution, nesting habitat, sociality), (2) characterize diversity patterns at the department level using species richness, Shannon index, and weighted endemism, (3) estimate undescribed species via rarefaction curves, and (4) compare species richness and phylogenetic diversity (Faith’s phylogenetic diversity, mean pairwise distance (MPD), mean nearest taxon distance (MNTD) and standardized effect sizes of MPD and MNTD) with countries of Gondwanan origin (Brazil, Chile) versus those in the Holarctic region (USA). Results We report 738 species across 123 genera and five families, including 246 new country records and 140 endemic species (19% of total fauna). Sampling effort was highly uneven: 41% of the records were concentrated in the Andean region, while xeric areas—where highest diversity is expected—remain critically undersampled. Species in the family Apidae dominated assemblages (69%), and the Andes ecoregion held the highest richness and endemism. Biological traits across the 738 species showed that solitary (57%) and above-ground nesting (57%) strategies predominate. Accumulation curves suggested that ∼26% of the bee fauna remains undescribed or unreported. Phylogenetic analyses did not support the hypothesis of higher diversity in Colombia relative to other countries of Gondwanan or Holarctic origin. We also found weak support for the relationship between species richness and geographic area across countries. Conclusions This study provides essential baseline knowledge for ecological, taxonomic, and conservation research of Neotropical bees. Geographic sampling biases highlight urgent needs for surveys in undersampled regions, especially xeric ecosystems. The multi-institutional network developed here demonstrates the value of collaborative frameworks for biodiversity documentation in megadiverse tropical regions and lays the foundation for long-term pollinator monitoring and conservation.