Effect Of Cadmium On Reproduction Of Brown Planthopper, Nilaparvata Lugens St(?)l

In this study, five treatments of cadmium concentrations (0, 6.25, 12.5, 25 and 50 mg·kg-1 soil) were established according to cadmium pollution levels in paddy fields, and the effects of cadmium on the fecundity, reproductive system, reproductive cells of the parental (P) and filial (F) generations, vitellin and total protein contents of female adults and eggs of brown planthoppers (BPHs) were examined. The results were as follows:1. Effects of cadmium on fecundity of BPH: the fertilities of both the P and F generations of BPH were significantly affected by cadmium stress. With increasing cadmium concentrations, the oviposition amount and hatchability declined gradually. The duration of eggs of both the P and F generations increased significantly in proportion to the cadmium concentration; the peak period of egg hatching was delayed; the daily hatchability of eggs was reduced, and the time of egg hatching was significantly prolonged.2. Effects of cadmium on the reproductive system of BPH: compared with the control samples, the length and the width of the abdomen of adults of the P and F generation of BPH, the width of the ovarian tumor in the female reproductive system, the length and the width of the lateral oviduct and the length of the vas deferens of the male adults were all significantly reduced.3. Effects of cadmium on reproductive cells of BPH: the volume of eggs of the P generation significantly decreased under cadmium stress. However, the variation in the volume of eggs in the F generation was diminished compared with the P generation after being stressed for two generations, and there was no significant difference compared with the control4. Effects of cadmium on the vitellin and the content of total protein in the female adults of BPH and its eggs: the content of total protein of the female adults in the spawning stage increased on a small scale without a significant difference after being affected by cadmium compared with the control samples. The content of vitellin in the female adults in the spawning stage was diminished in proportion to the cadmium concentration, indicating that cadmium has an inhibitory effect on the synthesis of vitellin. The content of total protein and vitellin in the eggs of BPH also tended to decline at elevated cadmium concentrations, indicating that cadmium has an inhibitory effect on the transfer of vitellin and other proteins and the normal development of BPH eggs.