Bee diversity in the shadows: Sampling gaps and richness estimates in Neotropical dry forests

Bees are important pollinators, most diverse in xeric and temperate regions, where sampling efforts are higher, while tropical areas, particularly the Neotropical Dry Forest (NDF), remain underrepresented in entomological collections. NDF is one of the most threatened biomes in the Neotropics and may host high bee diversity due to its arid climate. Preliminary results, based on occurrence records obtained from GBIF and the literature, suggest that NDF harbor at least 1,406 bee species, representing approximately 23% of the known bee richness in the Neotropics. However, most NDF regions show low occurrence density and clear sampling biases. To address this, the aim of this project was to estimate species completeness and expected bee richness in NDF using non-parametric estimators and potential distribution modeling. Using only museum-based records available through GBIF, we modeled the potential distribution of over 1,500 Neotropical bee species. Both the non-parametric estimators and the distribution models indicate a low completeness on bee richness at both the ecoregional and national levels. This reflects the lack of systematic diversity inventories and the variability in sampling efforts in existing surveys. Based on these methods, it is estimated that NDF could host around 2,426 bee species, corresponding to approximately 40% of the known bee fauna of the Neotropics.