关键词: 草地贪夜蛾, 镉胁迫, 植食性昆虫, 传递；赤眼蜂, 寄生

Abstract: 【Aim】To explore the influence of cadmium stress on the herbivore Spodoptera frugiperda and whether the parasitization capability of Trichogramma is affected by “bottom-up” cascade effect of cadmium. 【Methods】The larvae of S. frugiperda hatched within 24 h were fed with the artificial diets containing different concentrations (0, 0.2 and 51.2 mg/kg) of Cd²⁺, the growth and fecundity (number of eggs laid per female) of S. frugiperda and Cd²⁺ content in the eggs of F1 generation of S. frugiperda were investigated, and the parasitization capability and preference of T. dendrolimi adults to the eggs of S. frugiperda stressed by a low concentration (0.2 mg/kg) of Cd²⁺were also investigated. 【Results】Compared with the control (normal artificial diet), 0.2 and 51.2 mg/kg Cd²⁺in the artificial diet significantly prolonged the larval duration and significantly reduced the female pupal weight of S. frugiperda. The pupation rate, adult emergence rate, adult longevity and number of eggs laid per female of S. frugiperda in the treatment with high concentration (51.2 mg/kg) of Cd²⁺ decreased significantly. However, the number of eggs laid per female of S. frugiperda in the treatment with low concentration (0.2 mg/kg) of Cd²⁺ was slightly higher than that of the control, and the Cd²⁺ content in eggs of S. frugiperda in the low Cd²⁺concentration treatment was 1.03 mg/kg. The parasitism rate of T. dendrolimi on S. frugiperda eggs stressed by 0.2 mg/kg Cd²⁺ within 24 h was 52%, which was significantly higher than that of the control, while no significant differences were found in the adult emergence rate and proportion of females of F1 generation of T. dendrolimi between the treatment and control. When the eggs of S. frugiperda stressed by 0.2 mg/kg Cd²⁺ and the control eggs were separately and simultaneously exposed to T. dendrolimi females, the parasitism rate of T. dendrolimi adults on cadmium-stressed S. frugiperda eggs was significantly higher than that on the control eggs, while no significant differences were found in the adult emergence rate and proportion of females of F1 generation of T. dendrolimi when the two kinds of host eggs were separately and simultaneously provided. 【Conclusion】The results of this study suggest that cadmium stress affects the growth, development and fecundity of S. frugiperda, and cadmium in the artificial diet can be transferred into eggs via larval feeding, and affects the performance of T. dendrolimi.

Key words: Spodoptera frugiperda, cadmium stress, herbivorous insects, transfer; Trichogramma, parasitism