Physiology of insecticide-induced stimulation of reproduction in the rice brown planthopper (Nilaparvata lugens (Stål)): dynamics of protein in fat body and ovary

Abstract

This study concerns elucidating the physiology of insecticide-induced stimulation reproduction in Nilaparvata lugens (Stål) (Homoptera : Delphacidae). In insects, vitellogenesis involves the synthesis of the yolk protein precursor in the fat body and its deposition in the oocytes. Our investigations were specifically targeted at the dynamics of the protein content of both the fat body and ovary of adult females developed from the nymphs on rice plants treated with imidacloprid, triazophos and deltamethrin. The results show that the protein contents of the fat body and the ovary increased significantly in insects from rice plants which were subjected to insecticide foliar sprays at both tillering and yellow maturation stages, as compared to the controls from untreated plants. However, the amount of increase varied with insecticide, treatment concentrations and adult age. In general, the percent increase induced by triazophos and deltamethrin was generally greater than that induced by imidacloprid, and the higher concentration induced a greater increase than did the lower concentration. Protein contents of both fat body and ovary increased linearly with adult age.