Taxonomic Composition and Spatiotemporal Patterns of Crabronidae (Hymenoptera) in Southwestern China

Digger wasps (Crabronidae) are a diverse lineage of aculeate Hymenoptera, but their faunistic documentation in southwestern China remains scattered across historical and recent sources. We collected, compiled, cleaned, and taxonomically reviewed 373 occurrence records from 1909 to 2025, representing 264 coordinate localities across Yunnan, Sichuan, Guizhou, and Xizang Autonomous Region. The resulting working checklist contains 160 species in 30 genera, 11 tribes, and four subfamilies. Crabroninae contained 75 species (46.9%) and Pemphredoninae 70 species (43.8%), while Trypoxylon was the most species-rich recorded genus, with 22 species. Occurrence were highly uneven among regions: Yunnan contributed 310 records (83.1%) and 135 species, whereas Sichuan, Guizhou, and Xizang Autonomous Region contained 15, 13, and 11 species, respectively. Raw Jaccard similarity was highest between Sichuan and Guizhou (0.167), and the equal-record rarefied mean for that pair was 0.161 (95% CI 0.091–0.211). Record-order accumulation continued without a clear asymptote by the end of the compilation. Species-level occurrence was shallow: 81 species (50.6%) were represented by one locality, 147 (91.9%) by fewer than five localities, and 50 species (31.2%) had no record in the compilation during the previous 30 years. These patterns show that the available evidence is strongly shaped by collection and documentation history. Province-only records therefore should not be interpreted as evidence of endemicity or confirmed absence elsewhere. The compilation provides a reproducible baseline for future field surveys and taxonomic revision, especially in the less documented regions of Sichuan, Guizhou, and Xizang Autonomous Region.