Sublethal and transgenerational effects of sulfoxaflor on the demography and feeding behaviour of the mirid bug Apolygus lucorum

Sulfoxaflor, the first commercially available sulfoximine insecticide, has been used for the control of sap-feeding insect pests such as plant bugs and aphids on a variety of crops. However, its sublethal effects on the mirid bug Apolygus lucorum, one of the key insect pests of Bt cotton and fruit trees in China, have not been fully examined. Here, we evaluated the demography and feeding behaviour of A. lucorum exposed to sulfoxaflor. The leaf-dipping bioassay showed that the LC(10) and LC(30) of sulfoxaflor against 3(rd)-instar nymphs of this insect were 1.23 and 8.37 mg L(-1), respectively. The LC(10) significantly extended the nymphal duration and decreased the oviposition period by 5.29 days and female fecundity by 56.99% in the parent generation (F0). The longer duration of egg, 5(th)-instar nymphs, preadult, and male adult longevity were observed in the F1 generation (F1) at LC(10). At the LC(30), the duration of egg and 1(st)-instar nymph, female adult longevity, and oviposition period of the F1 were significantly shorter, while the nymphal duration in the F0 and duration of 5(th)-instar nymphs, preadult survival rate, and male adult longevity in the F1 significantly increased. The net reproductive rate (R(0)), intrinsic rate of increase (r), and finite rate of increase (λ) in the F1 were not significantly affected by these two concentrations, whereas the mean generation time (T) was lower at the LC(30). Additionally, the probe counts and cells mixture feeding time were markedly lengthened by the LC(10) and LC(30), respectively, when A. lucorum nymphs exposed to sulfoxaflor fed on Bt cotton plants without insecticides. These results clearly indicate that sulfoxaflor causes sublethal effects on A. lucorum and the transgenerational effects depend on the tested concentrations.