Abstract:  【Aim】This study aims to explore the sublethal effects of chlorpyrifos on Sogatella furcifera, so as to provide a theoretical basis for the rational use of insecticides to control S. furcifera.【Methods】The 3rd instar nymphs of S. furcifera were treated with LC₁₀ (1.5 mg/L) and LC₂₅(2.9 mg/L) of chlorpyrifos using rice stem dipping method. The female adult longevity, adult emergence rate and number of eggs laid per female adult of the F₀ generation were detected. The age-stage, two-sex life table of the F₁ generation was constructed to analyze the changes in the developmental duration, fecundity and survival rates. The relative expression levels of reproduction-related genes (SfRheb, SfTOR, SfS6K, SfHMGR, SfIPPI, SfFPPS1, SfFPPS2, SfJHAMT, SfFAMeT, SfMet, SfKrh1 and SfVg) in the F₀ adult females were determined by RT-qPCR.【Results】The numbers of eggs laid per F₀ female adult of S. furcifera in the treatment groups with LC₁₀ and LC₂₅ of chlorpyrifos were significantly reduced, and the adult emergence rate and female adult longevity of the F₀ generation in the treatment group with LC₂₅ of chlorpyrifos were shortened significantly, as compared with those in the control group treated with distilled water. The average numbers of eggs laid per F₁ female adult in the treatment groups with LC₁₀ and LC₂₅ of chlorpyrifos were 191.4 and 169.9, respectively， both significantly lower than that in the control group (230.6). Exposure of the 3rd instar nymphs of S. furcifera to LC₂₅ of chlorpyrifos significantly shortened the female adult duration of the F₁ generation and reduced the survival rate of the F₁ generation of S. furcifera, compared to the control. Furthermore, exposure of the 3rd instar nymphs of S. furcifera to LC₁₀ and LC₂₅ of chlorpyrifos inhibited the expression of genes (SfFAMeT, SfFPPS1, SfFPPS2 and SfKrh1) related to juvenile hormone (JH) signaling pathways, genes (SfRheb and SfTOR) related to TOR signaling pathways, and SfVg in female adults of the F₀ generation. 【Conclusion】Sublethal concentrations of chlorpyrifos stress inhibited the growth, development, survival rate and fecundity of S. furcifera, thereby suppressing the population growth of subsequent generations to a certain extent. Furthermore, sublethal concentrations of chlorpyrifos also down-regulated the expression of genes related to the TOR and JH signaling pathways. These findings provide a theoretical basis for the scientific control of S. furcifera in the field and lay a foundation for understanding the molecular mechanisms by which insecticides regulate insect reproduction.

Key words: Sogatella furcifera, chlorpyrifos, sublethal effect, age-stage, two-sex life table, fecundity, growth and development