小菜蛾的耐热性

小菜蛾是世界范围内十字花科蔬菜上的重要害虫.临界高温(critical thermal maxi-mum,CTMax)是昆虫耐热性的常用指标.采用动态加热方法,利用自行组装的装置测定了小菜蛾的临界高温,以此作为其耐热性指标,研究发育阶段、饲养温度、世代、性别和热激对小菜蛾耐热性的影响.结果表明:25℃下饲养的小菜蛾4龄幼虫的CTMax均值为50.31℃,显著高于1龄幼虫(43.03℃)、2龄幼虫(46.39℃)、3龄幼虫(49.67℃)以及雌性成虫(45.76℃)和雄性成虫(47.73℃);不同饲养温度(20、25和30℃)下成虫耐热性无显著差异;30℃下饲养1代、3代及6代的不同世代成虫CTMax也无显著变化;所有处理雌雄成虫的CTMax无显著差异;40℃下45 min热激可使5日龄雄成虫的CTMax值从45.51℃增加到46.49℃.

Thermal tolerance of diamondback moth Plutella xylostella

Diamondback moth Plutella xylostella is a worldwide important pest on cruciferous vegetables. Critical thermal maximum (CTMax) is often used as an index for the thermal tolerance of insects. By the method of dynamic heating, this paper measured the CTMax of P. xylostella in a self-assembled device, and studied the effects of development stage, rearing temperature, generation, sex, and heat shock on the thermal tolerance of P. xylostella based on the CTMax values. Reared at 25 degrees C, the mean CTMax of the 4th larva (50.31 degrees C) was significantly higher than that of the 1st larva (43.03 degrees C), 2nd larva (46.39 degrees C), 3rd larva (49.67 degrees C), female adult (45.76 degrees C), and male adult (47.73 degrees C); reared at 20, 25, and 30 degrees C, the adults had no significant difference in their CTMax; reared at 30 degrees C for 1-, 3-, and 6 generations, the CTMax of the adults also had no significant difference. In all the treatments, the CTMax of the female and male adults had less difference. Heat shock with 40 degrees C for 45 minutes could make the CTMax of 5 day-old male moth increased from 45.51 degrees C to 46.49 degrees C.