Effect of Bt-Cry1Ab Maize Commercialization on Arthropod Community Biodiversity in Southwest China

Transgenic Bt maize commercialization has become a critical pest management strategy against lepidopteran insects in southwest China, but its ecological impact on arthropod biodiversity remains insufficiently characterized. This two-year field investigation (2023-2024) conducted in Bazhong City, Sichuan Province utilized systematic field monitoring to compare arthropod community dynamics between conventional maize and Bt-Cry1Ab maize (DBN9936) cultivation systems. This study documented 575,970 arthropod specimens representing 80 species/types across 45 families and 17 orders. Analysis of variance revealed significant differences (<i>p</i> < 0.05) between non-Bt and Bt maize in the abundance and species richness of target herbivorous pests, non-target herbivorous pests, and natural enemy insects. Field investigations revealed a notable absence of <i>Macrocentrus cingulum</i>, a key larval parasitoid of <i>Ostrinia furnacalis</i>, in Bt-maize plots compared to conventional counterparts. The populations of non-target herbivorous pests and natural enemies such as Aphididae, <i>Chrysoperla sinica</i>, <i>Frankliniella tenuicornis</i>, and <i>Orius sauteri</i> were higher in Bt maize fields than in non-Bt maize fields, while the populations of target herbivorous pests including <i>O. furnacalis</i> and <i>Mythimna loreyi</i> were lower than those in non-Bt maize fields. However, no significant differences (<i>p</i> > 0.05) were observed in arthropod abundance, species richness, or in a suite of ecological indices including the Simpson diversity index, Shannon-Wiener diversity index, Pielou evenness index, McIntosh diversity index, and community stability indices (<i>N</i>_n/<i>N</i>_p, <i>N</i>_d/<i>N</i>_p, and <i>S</i>_d/<i>S</i>_p). Redundancy analysis identified maize growth stages (6.75% variance explained) and interannual variations (2.44%) as principal drivers of arthropod community dynamics, with maize genotype contributing minimally (1.53%). These findings demonstrate that Bt-Cry1Ab maize (DBN9936) cultivation maintains functional arthropod community structure while effectively controlling target pests, providing substantial empirical evidence to support its sustainable deployment in southern China's agricultural landscapes.