Yu Yue-Shu, Xue Shan, Wu Jin-Cai, Wang Fang, Yang Guo-Qin
Plant Protection College, Yangzhou University, Yangzhou 225009, People's Republic of China.
J Econ Entomol. 2007 Aug;100(4):1188-93. doi: 10.1603/0022-0493(2007)100[1188:cilojh]2.0.co;2.
Insect hormones regulate growth and development and fecundity of insects. The current study investigated changes in juvenile hormone (JH) and molting hormone (MH) levels in fourth instars and adult females of Chilo suppressalis (Walker) (Lepidoptera: Pyralidae) after imidacloprid application to rice, Oryza sativa L. The results showed that JH level in fourth instars that developed feeding on Fengyouxiangzhan rice plants sprayed with 15, 30, and 60 ppm imidacloprid was significantly higher than that of larvae that developed on control plants, increasing by 5.04, 6.39, and 4.89 times, respectively. The relationships between JH level and imidacloprid concentrations showed a significant negative correlation. In contrast, molting hormone (MH) level in larvae fed on control plants was significantly higher than that on treated plants. JH:MH values in fourth instars developed from larvae feeding on rice plants treated with 15, 30, 60, 80, and 100 ppm imidacloprid increased by 49.17, 39.43, 13.48, 15.80, and 0.2 times, respectively, compared with control. JH and JH:MH ratio in larvae fed on Wujing 15 plants treated with imidacloprid were significantly lower than those fed on Fengyouxiangzhan under the same treatments. JH level in adult females that developed from larvae feeding on rice plants sprayed with imidacloprid significantly decreased with increase in imidacloprid concentration, but it increased compared with control. JH level in adult females was associated with times of imidacloprid application. JH level in adult females developed from larvae feeding on rice plants after double spray with 30 ppm imidacloprid was significantly higher than control, increasing by 61.6 and 116.5%, respectively, compared with a single spray and the control. Moreover, hormone levels in the larvae were related to the application method of imidacloprid. JH level in fourth instars after root application and topical application of imidacloprid was significantly lower than in control. Thus, the dynamics of JH and MH in insects after insecticide applications are an extremely interesting problem, because hormones are related to insect growth and development.
昆虫激素调节昆虫的生长、发育和繁殖力。本研究调查了在水稻（Oryza sativa L.）上施用吡虫啉后，二化螟（Chilo suppressalis (Walker)，鳞翅目：螟蛾科）四龄幼虫和成虫雌虫体内保幼激素（JH）和蜕皮激素（MH）水平的变化。结果表明，取食喷施15、30和60 ppm吡虫啉的丰优香占水稻植株的四龄幼虫体内的JH水平显著高于取食对照植株的幼虫，分别增加了5.04、6.39和4.89倍。JH水平与吡虫啉浓度之间呈显著负相关。相反，取食对照植株的幼虫体内的蜕皮激素（MH）水平显著高于取食处理植株的幼虫。取食喷施15、30、60、80和100 ppm吡虫啉的水稻植株的幼虫发育而成的四龄幼虫体内的JH:MH值与对照相比分别增加了49.17、39.43、13.48、15.8 和0.2倍。在相同处理下，取食喷施吡虫啉的武粳15植株的幼虫体内的JH和JH:MH比值显著低于取食丰优香占的幼虫。取食喷施吡虫啉的水稻植株的幼虫发育而成的成虫雌虫体内的JH水平随着吡虫啉浓度的增加而显著降低，但与对照相比有所升高。成虫雌虫体内的JH水平与吡虫啉的施用次数有关。取食喷施30 ppm吡虫啉的水稻植株的幼虫发育而成的成虫雌虫在二次喷施后体内的JH水平显著高于对照，与单次喷施和对照相比分别增加了61.6%和1
