Abstract

This study explores the latitudinal diversity gradient (LDG) of wild bees (Hymenoptera: Anthophila) in Chile, a region with diverse climates and geographic isolation. By examining species richness patterns, this research seeks to uncover the key factors influencing these patterns in Chilean bees. We compiled and analysed occurrence records of wild bee species from five families, evaluating species richness across latitudinal gradients. To explain the LDG, we tested hypotheses such as Rapoport's effect, the mid-domain effect (MDE), source-sink dynamics, and the Climatic Variability Hypothesis. Additionally, we conducted cluster analyses and beta diversity assessments to identify distinct ecoregions and understand patterns of species turnover and nestedness along these gradients. Our analysis revealed a mid-latitudinal peak in wild bee species richness around 34 degrees S, consistent with the global bimodal latitudinal gradient for bees. The data did not support MDE predictions, implying that geometric constraints alone cannot explain these patterns. Instead, the positive correlation between latitudinal extent and latitude supports Rapoport's effect, indicating broader environmental tolerances at higher latitudes. Beta diversity analyses showed that species turnover, not nestedness, drives diversity variation along latitudinal gradients, reflecting significant species replacement across latitudes due to changing environmental conditions. Cluster analyses identified distinct wild bee groups corresponding to Northern, Central, and Southern Chile ecoregions, reinforcing substantial shifts in species composition across latitudinal bands. Our findings emphasise the importance of stable climates in supporting high bee species richness and broader environmental tolerances at higher latitudes. Understanding these patterns is vital for predicting biodiversity responses to climate change and guiding conservation strategies, especially in Chile's biodiversity hotspots with high species richness and endemism.