Non-Target Arthropod Community Variation Associated with Abamectin Trunk-Injection History in a Pinus massoniana Plantation.

Abamectin trunk injection is used to control pine wilt disease, but field evidence linking injection history to non-target arthropod communities is limited. We compared uninjected plots with plots injected once in March 2024 (ATI1) or March 2022 (ATI3) in a Pinus massoniana plantation in the Qinling-Daba Mountains. Three plots per history were sampled in July, September, and November 2025. Morphological identification and cytochrome c oxidase subunit I metabarcoding characterized soil-associated arthropods and aboveground Hymenoptera; feeding guilds were assigned at the family level. Litter residues and soil properties were measured. Overall Shannon diversity did not differ significantly among histories in either assemblage. Overall composition differed significantly for soil-associated arthropods but not Hymenoptera. Compositional differences occurred among soil detritivores, herbivores, and microbivores and among hymenopteran parasitoids, predators, and pollinators. Hymenopteran herbivore and pollinator diversity was higher in ATI1 and ATI3, respectively, whereas no soil feeding guild showed significant diversity differences. Residues were detected in both injected groups and were higher in ATI1. Redundancy analysis suggested directional associations with residues or soil properties, but these were descriptive rather than evidence of significant correlations. Injection-history associations were taxon- and metric-specific, supporting integrated diversity, composition, and feeding-guild assessments in non-target monitoring and risk evaluation.