Multigenerational effects of nano cerium and zinc-selenium quantum dots on Spodoptera frugiperda (Fall Armyworm)

The effects of nanomaterials on insect pests have been a rich research focus, especially in the last decade. This study evaluated the multigenerational impact of a nanocomposite comprising nano cerium dioxide (nCeO₂) and zinc-selenium (ZnSe) quantum dots (QDs) on Spodoptera frugiperda (fall armyworm, FAW), a key pest of maize and sorghum. We hypothesized that higher concentrations and prolonged exposure would negatively affect larval and pupal development, with transgenerational effects observed. Third instar larvae were exposed to six concentrations (0 to 100 ppm) of the nanocomposite through an artificial diet under acute and chronic feeding regimes. Larval weight gain, pupal weight, and adult emergence were assessed in the F₁ generation; larval and pupal weights were recorded in the F₂. Results showed clear dose-dependent developmental disruptions in F₁, with significant reductions in larval and pupal weights at ≥ 80 ppm under acute exposure and from 60 ppm under chronic exposure. Adult emergence was largely unaffected by acute exposure but declined under chronic exposure at 60 ppm or higher. In contrast, the F₂ generation exhibited no significant differences in larval or pupal weights under either feeding regime, indicating potential physiological recovery or adaptation. These findings suggest that while nCeO₂ and ZnSe QDs at higher concentrations can negatively affect FAW development in the first generation, such effects may not persist in subsequent generations under sublethal conditions. Nutritional indices further revealed significant impairments in growth rate, conversion efficiency, and assimilation at concentrations ≥ 80 ppm, reinforcing the adverse effects observed in the F₁ generation.