Abstract: This study was conducted in Tianma National Nature Reserve of the Dabie Mountains, western Anhui, to explore the relationship between insect diversity and environmental factors in the climatic transition zone. From March to October 2023, insect diversity was investigated across four elevation sections by collecting insects in 16 plots measuring 20 m × 20 m each with the Malaise trapping method. A total of 29942 specimens were collected, belonging to 13 orders, 122 families, and 440 species. Diptera, Hymenoptera, Coleoptera, and Lepidoptera were the dominant groups. The Simpson, Shannon, and Margalef indices were the highest at an altitude of 350-650 m and lowest at 1250-1550 m. The Pielou index was the highest at 950-1250 m and lowest at 650-950 m. Non-metric multidimensional scaling (NMDS) results showed significant differences in insect communities across different elevation sections. There was a declining trend of species richness along the altitudinal gradient (P<0.001), an increasing trend with rising average temperature (P<0.001), and a rise-then-fall trend with the maximum temperature difference (P<0.01). Altitude, mean temperature, and maximum temperature difference were significantly correlated with on insect diversity. Our results enriched the basic data of biodiversity in Dabie Mountains and provided references for monitoring and protecting insect diversity in the climatic transition zone from the north subtropical to south warm temperate zone.

Key words: mountain insects, climatic transition zone, insect community composition, environmental factor, species diversity