Habitat-Driven Insect Community Structure in an Arid Agroecosystem of Xinjiang, China: Integrated Light-Trap Monitoring and DNA Barcoding Evidence

Research on insect biodiversity in arid and semi-arid agroecosystems of Central Asia remains limited, hindering the development of effective insect conservation strategies and integrated pest management (IPM) programs. This study examined insect community structure, diversity, and seasonal dynamics across three habitat types in Kekedala City, in the autonomous region of Ili Kazakh, Xinjiang, China. Solar-powered ultraviolet LED light traps (350–420 nm) were used for sampling from April to August 2024. A total of 63,090 individuals of 83 species, 57 families and 72 genera of insects were collected. Diversity indices calculated using the complete species dataset showed highest diversity in the riparian corridor (L3: H′ = 3.42, D = 0.962, S = 62), intermediate diversity in the agro-horticultural garden (L2: H′ = 3.18, D = 0.948, S = 54), and lowest diversity in the xerophytic shrubland (L1: H′ = 2.97, D = 0.935, S = 47). A supplementary analysis targeted a shared core assemblage of 17 species, defined as taxa captured at all three sampling sites with cumulative total abundances ranging from 50 to 100 individuals. This subset exhibited near-uniform diversity metrics across habitats (H′ = 2.83, D = 0.941, Pielou’s evenness J′ ≈ 1.0), a pattern driven by the prevalence of habitat generalists rather than capturing site-specific full community diversity. Two abundant pest species, Helicoverpa armigera (Hübner, 1808) (cotton bollworm, 5209 individuals, 8.3% of total) and Oryctes rhinoceros (Linnaeus, 1758) (rhinoceros beetle, 5206 individuals, 8.2% of total), both peaked in abundance in July–August; O. rhinoceros is associated with local ornamental and date palm plantings in the study area. In total, 15 major pest species were recorded. Mitochondrial cytochrome c oxidase subunit I (COI) DNA barcoding confirmed two new national insect records for China: Stethoconus pyri (Mella, 1861) (Hemiptera: Anthocoridae) and Pinacoplus didymogramma (Hampson, 1907) (Lepidoptera: Noctuidae). This study provides the first comprehensive baseline inventory of the insect fauna of Kekedala City. Descriptive ordination analyses suggest that habitat vegetation complexity may exert a stronger filtering effect on insect assemblage composition than the relatively small seasonal variation in temperature and humidity observed during the sampling period. As only a single trap was deployed within each habitat with no within-site replication, all cross-habitat community patterns reported herein are strictly descriptive and require validation via replicated field sampling in future research.