Key areas for conserving and sustainably using oil-collecting bees (Apidae: Centridini, Tapinotaspidini, Tetrapediini) in the Americas

The solitary oil-collecting bees of the tribes Centridini, Tapinotaspidini, and Tetrapediini inhabit areas from the southern part of the Nearctic Region through the Patagonian in southern South America, including the Caribbean. These bees are morphologically and behaviorally specialized in collecting oils as a reward from specialized floral glandular structures present in oil-producer plants. Oil-producer plants and oil-collecting bees have a mutualistic relationship in which the latter potentially pollinate the formers while collecting oils from their flowers. The main objective of this work is to infer the species richness and the key areas for conservation, research, and sustainable use of oil-collecting bees of the tribes Centridini, Tapinotaspidini, and Tetrapediini in the Americas. We collected occurrence records for 528 species of oil-collecting bees and estimated the species richness for each tribe and genus. In total, we estimated 664 species across the three mentioned tribes. With that baseline information, we created models of the richness and rarity patterns of the entire group of species and each tribe as a criterion to highlight key areas, along with richness and rarity centers for the American oil-collecting bees. We identified several critical areas that can be prioritized for conservation and research projects, including territories in Panama, Costa Rica, the Central and Northern Andes, the Amazon basin, and the biogeographic provinces of Cerrado, Atlantic Forest, Pampean, and Chacoan.