Spatiotemporal Population Genomics of the Invasive Whitefly Bemisia tabaci MED in China: Implications for Surveillance and Sustainable Control.

Bemisia tabaci MED is one of the most invasive and destructive agricultural pests worldwide, posing a serious threat to crop production and biosecurity. Understanding its spatiotemporal population dynamics and genetic structure is critical for early detection, effective surveillance, and sustainable management. Previous studies have shown that B. tabaci MED in China has a high genetic structure and an unstable genetic composition. The annual genetic dynamics of the B. tabaci MED population have not been investigated throughout the outbreak phase that began in 2008. Here, we report the use of 2b-RAD sequencing to estimate the spatial and temporal genetic structure of B. tabaci MED in Shandong Province over several years. We examined 198 individuals from five sites over four years (2008, 2013, 2015, and 2017). Although populations showed generally low within-population diversity (Shannon I ≤ 0.407) and a high gene flow, clear temporal differentiation emerged between the early invasion phase (2008) and later outbreak years (2013-2017). Furthermore, specific populations, notably 2017 Liaocheng and Zaozhuang, retained distinct genetic signatures compared with other regions, suggesting localized founder effects or adaptation. Our study underscores the importance of integrating high-resolution genomic tools into invasive pest surveillance programs, and understanding this heterogeneity is critical for targeted surveillance, quarantine prioritization, and sustainable management strategies.