取食不同食物的草地贪夜蛾的过冷却点和结冰点

为探明草地贪夜蛾的抗寒能力及取食不同寄主植物对其抗寒能力的影响,本试验对取食人工饲料及小麦、玉米和高粱等三种不同寄主植物的草地贪夜蛾部分虫态的过冷却点和结冰点进行了测定。试验结果表明:人工饲料饲养的草地贪夜蛾不同虫态间过冷却点和结冰点存在显著差异,其中蛹的过冷却点和结冰点最低,分别为(-16.71±0.26)℃和(-5.04±0.21)℃,显著低于其他虫态;3~6龄幼虫的过冷却点和结冰点随龄期增大而升高。取食3种不同寄主植物的草地贪夜蛾蛹的过冷却点和结冰点显著低于幼虫和成虫。在不同寄主植物之间,取食玉米的草地贪夜蛾蛹的过冷却点最低。除取食高粱的4龄幼虫外,取食3种寄主植物的幼虫的过冷却点均随龄期增大而升高。取食3种寄主植物的雌成虫过冷却点无显著差异,但取食高粱的雄成虫过冷却点显著低于取食小麦的。

Supercooling and freezing points of Spodoptera frugiperda feeding on different foods

In order to understand the cold resistance of Spodoptera frugiperda and the effects of different host plants on their cold resistance,the supercooling point and the freezing point of S.frugiperda fed on artificial diet and three different host plants including wheat,corn and sorghum were measured.The results showed that the supercooling points and the freezing points of S.frugiperda at different developmental stages were significantly different when fed on artificial diet,and the pupa possessed the lowest supercooling point and freezing point,which were(-16.71±0.26)℃and(-5.04±0.21)℃,respectively.The supercooling point and freezing point of larva increased with the instars.The pupa also showed the lowest supercooling point and freezing point compared to other developmental stages when reared on three different host plants.Among different hosts,the pupa developed on corn showed the lowest supercooling point.The supercooling point of larvae feeding the three hosts increased with the instars except the 4th instar on sorghum.The supercooling points of the female adult developed on three hosts showed no significant difference,but the male adult developed on sorghum had a significantly lower supercooling point than that on wheat.