Sublethal and transgenerational effects of nitenpyram on Acyrthosiphon gossypii and its impacts on symbiotic bacteria

Mutualism between insects and symbiotic bacteria drives insect evolution, and insecticide resistance is affected by symbiotic bacteria, increasing the complexity of pest resistance. This study evaluated the sublethal and transgenerational effects of the neonicotinoid insecticide nitenpyram on the population dynamics of Acyrthosiphon gossypii and measured its impact on the symbiotic bacterial community. The results showed that LC₂₀ (2.49 mg L⁻¹) of nitenpyram significantly reduced the fecundity and lifespan of the parent G0 generation of A. gossypii, and had similar inhibitory effects on its G1 and G2 generations. Compared with those of control group, the population parameters λ (finite rate of increase), R₀ (net reproductive rate), and r (intrinsic increase rate) of G1 and G2 were significantly reduced, but mean generation time (T) was increased. Nitenpyram treatment affected the biological traits of A. gossypii, and also changed the relative abundance of Buchnera and Sphingomonas in three consecutive generations G0-G2. Under nitenpyram treatment, the relative abundance of Buchnera decreased in G0, while that of Sphingomonas increased. The relative abundance of Buchnera increased in G1 and G2, but that of Sphingomonas decreased. Our findings may provide a new perspective for evaluating the potential effects of pesticides on aphids.