Liu Qingsong,Romeis Jörg,Yu Huilin,Zhang Yongjun,Li Yunhe,Peng Yufa
We determined whether plant volatiles help explain why Cotesia chilonis (a parasitoid of the target pest Chilo suppressalis ) is less abundant in Bt than in non- Bt rice fields. Olfactometer studies revealed that C. chilonis females responded similarly to undamaged Bt and non- Bt rice plants. Parasitoids preferred rice plants damaged by 3 rd -instar larvae of C. suppressalis, but did not differentiate between caterpillar-infested Bt and non- Bt plants. According to GC-MS analyses of rice plant volatiles, undamaged Bt and non- Bt rice plants emitted the same number of volatile compounds and there were no significant differences in the quantity of each volatile compound between the treatments. When plants were infested with and damaged by C. suppressalis larvae, both Bt and non- Bt rice plants emitted higher numbers and larger amounts of volatile compounds than undamaged plants, but there were no significant differences between Bt and non- Bt plants. These results demonstrate that the volatile-mediated interactions of rice plants with the parasitoid C. chilonis were not disrupted by the genetic engineering of the plants. We infer that parasitoid numbers are lower in Bt than in non- Bt fields because damage and volatile induction by C. suppressalis larvae are greatly reduced in Bt fields.
Tian Jun-Ce,Chen Yang,Shelton Anthony M,Zheng Xu-Song,Xu Hong-Xing,Lu Zhong-Xian
Most adult parasitoids depend on carbohydrate-rich food as an energy source for longevity, fecundity, and mobility. Thus, providing sugars has been proposed as a technique to maximize the biological control efficacy of parasitoids. However, the sugars provided for parasitoids need to be carefully selected because herbivore hosts might also benefit. Here we explore the effects of 12 naturally occurring sugars on the longevity and fecundity of the rice pest, Chilo suppressalis, and the longevity of its parasitoid, Cotesia chilonis, as well as the effect of sugars on sugar consumption of C. chilonis. Results showed that none of the tested sugars significantly impacted the longevity of C. suppressalis, but fructose, glucose, maltose, and sucrose significantly increased its fecundity. The longevity of C. chilonis was significantly increased when fed fructose, glucose, sucrose, maltose, trehalose, and melezitose. Our data suggest that C. chilonis consumed larger quantities of glucose, fructose, and sucrose followed by maltose, melezitose, and trehalose and the longevity of C. chilonis was positively correlated to sugar consumption. Our data also suggest that the herbivore C. suppressalis and its parasitoid C. chilonis responded differently to trehalose and melezitose. Although additional studies are needed, our data suggest that these sugars could be considered as candidate components for sugar sprays to enhance the activity and efficacy of C. chilonis, but without benefiting its pest host.
危险品化学品经营许可证（带存储）