变温贮藏僵蚜对烟蚜茧蜂耐寒能力的影响

Effects of fluctuating thermal regime on cold tolerance of parasitoid wasp Aphidius gifuensis

为明确变温贮藏以麦二叉蚜为寄主的僵蚜对烟蚜茧蜂耐寒能力的影响,探究其体内的生化物质变化规律,测定了变温处理后羽化的烟蚜茧蜂雌雄成虫过冷却点、结冰点、体内含水量、脂肪、蛋白质和总糖含量的变化.结果表明:与对照(20℃)相比,经4℃22h/20℃2 h和4℃46h/20℃2h处理1周后烟蚜茧蜂的耐寒能力显著增强.经变温处理后,烟蚜茧蜂雌雄个体的过冷却点、结冰点均出现不同程度的下降,雌蜂经4℃22h/20℃2h处理后过冷却点和结冰点最低,分别为-26.38和-25.51℃;雄蜂经4℃46h/20℃2h处理后过冷却点和结冰点最低,分别为-26.82和-26.38℃.经变温处理后烟蚜茧蜂僵蚜雌雄个体体内糖和蛋白质含量上升而脂肪和体内含水量下降,尤以经4℃22h/20℃2h和4℃46h/20℃2h处理后的变化最为明显.变温可以提高烟蚜茧蜂僵蚜的低温抵抗能力,且其耐寒能力的增加与其体内生化物质含量的变化密切相关.僵蚜经4℃22h/20℃2h和4℃46h/20℃2h贮藏1周后更有利于烟蚜茧蜂的生存和实践应用.

In order to understand the effects of fluctuating thermal regime（FTR） on the cold tolerance of female and male Aphidius gifuensis adults in the mummies of Schizaphis graminum and to explore the variation patterns of the biochemical substances in the adult body,this paper determined the supercooling point（SCP）,freezing point（FP）,and the water,fat,protein,and carbohydrate contents of the adults after FTR treatments.Compared with that at constant temperature（20 ℃）,the cold tolerance of the adults at 4 ℃ 22 h/20 ℃ 2 h and 4 ℃ 46 h/20 ℃ 2 h after 1 week enhanced significantly.The SCP and FP after FTR presented a downtrend,being the lowest（-26.38 ℃ and-25.51 ℃,respectively） for the female adults after 1 week of 4 ℃ 22 h/20 ℃ and the lowest（-26.82 ℃ and-26.38 ℃,respectively） for the male adults after 1 week of 4 ℃ 46 h/20 ℃ 2 h.After FTR,the carbohydrate and protein contents of the female and male adults increased while the fat and water contents were in adverse,with distinct changes after 1 week of 4 ℃ 22 h/20 ℃ 2 h and 4 ℃ 46 h/20 ℃ 2 h.The results indicated that FTR could enhance the cold tolerance of A.gifuensis adults,which was closely related to the variations of the biochemical substances in the adult body,and the treatments 4 ℃ 22 h/20 ℃ 2 h and 4 ℃ 46 h/20 ℃ 2 h for 1 week were most advantageous to the survival and practical application of A.gifuensis.