取食量对斜纹夜蛾生长发育的影响

通过控制取食量的方法模拟拒食作用，研究了不同取食量和印楝素拒食处理对斜纹夜蛾幼虫生长发育的影响．结果表明，食物量的减少对斜纹夜蛾幼虫的生长发育有明显的抑制作用．对斜纹夜蛾3龄幼虫进行控制取食量处理，发现随取食量的降低，生长抑制作用增大，试虫的发育历期延长，死亡率增高，但化蛹率和羽化率所受影响不大．用不同浓度的印楝素处理斜纹夜蛾3龄幼虫，发现随印楝素浓度的增高，对斜纹夜蛾幼虫的生长抑制作用越明显．印楝素拒食处理使试虫的发育历期延长，死亡率升高，这与控制取食量的结果相似，但印楝素使试虫的化蛹率和羽化率明显降低，这与控制取食量的结果有差别．

Effects of Feeding Amount on the Growth and Development of Tobacco Cutworm Larvae

Effects of controlled feeding on the growth and development of tobacco cutworm larvae (Spodoptera litura) were studied.In contrast with azadirachtin,the growth and development of tobacco cutworm were measured under natural condition.The 3rd instar larvae of tobacco cutworm were treated with controlled feeding.The results showed that the fewer was the feeding amount,the greater the effect of growth inhibition was,the longer the duration of development was and the higher the mortality was.But the pupation rate and eclosion rate were not obviously affected.The 3rd instar larvae of tobacco cutworm were treated with azadirachtin at different concentration.Results showed that the higher the concentration of azadirachtin was,the greater the effect of growth inhibition was.The duration of larvae treated with azadirachtin became longer and the mortality was higher.It was similar with the results of controlled feeding.Moreover, the pupation rate and eclosion rate of larvae treated with azadirachtin were obviously lower, and it did not tally with the results of controlled feeding.The probable reason was that azadirachtin had inhibition activity of growth and development in addition to antifeeding activity.