Multigeneration Sublethal Chlorantraniliprole Treatment Disrupts Nutritional Metabolism and Inhibits Growth, Development, and Reproduction of Phthorimaea absoluta

Phthorimaea absoluta, an important pest of tomato crops, has reportedly developed high levels of resistance to the insecticide chlorantraniliprole, which has a unique mode of action and high efficacy. This study evaluated the sustained multigenerational effects of chlorantraniliprole on P. absoluta, focusing on resistance development, growth, development, reproductive capacity, population parameters, and nutritional indicators. After continuous selection with sublethal chlorantraniliprole for eight generations (CX-Sub8), bioassays showed that CX-Sub8 had 225.37-fold higher resistance than the susceptible strain. The age-stage, two-sex life table analysis revealed that the preadult development time and mean generation time were significantly prolonged, while population reproduction and pupal weight were reduced. Moreover, the relative fitness of CX-Sub8 was 0.62, and changes in the life table parameters correlated with an increase in the serial number of selection cycles. The second-instar larvae of CX-Sub8 presented lower triglyceride, glycerol, trehalose, free fatty acid, and protein contents than the unselected strain (CX-S8). Transcriptome analysis identified 2517 differentially expressed genes, with most being enriched in nutrient metabolism-related pathways, such as amino acid biosynthesis and fatty acid degradation metabolism. These results indicate that multigenerational sublethal chlorantraniliprole treatment disrupts the nutritional metabolism, and inhibits the growth, development, and reproduction of P. absoluta.