Effects of benzothiazole on survival for reduced reproduction and development in Tribolium castaneum Herbst (Coleoptera: Tenebrionidae).

Background: The red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), is an important stored-product pest that is distributed worldwide and has developed resistance to many insecticides. Identifying novel and effective alternative insecticides is important for the control of T. castaneum. The volatile compound benzothiazole has been identified as having great acute toxic activity against T. castaneum. However, a comprehensive evaluation of a new insecticide should include both direct toxic effects and sublethal effects. The aim of this study was therefore to evaluate the effects of benzothiazole on the development and reproduction of T. castaneum.

Results: Exposure of fourth-instar larvae to lethal and sublethal concentrations of benzothiazole (LC , LC and LC ) significantly decreased pupation rates, food intake and growth rates in T. castaneum. Larval duration was significantly reduced by approximately 1 day in the LC and LC treatment groups. The LC benzothiazole caused a significant decrease in the weight of pupae and adults, fecundity and egg hatchability. Increased and decreased nutrient (carbohydrate and lipid) contents were observed in surviving larvae and pupae, respectively. The LC and LC treatments caused the down-regulation of five growth-positive regulated genes (PI3K, AKT, CyclinE, S6K1 and S6K2) and the up-regulation of two growth-negative regulated genes (4EBP and FOXO).

Conclusion: Benzothiazole presented adverse effects on the development and reproduction of T. castaneum, further supporting benzothiazole as a highly active compound in stored-product protection. © 2020 Society of Chemical Industry.