旋幽夜蛾各虫态的过冷却点测定

The supercooling point of different stages of the clover cutworm,Scotogramma trifolii

［目的］ 探明旋幽夜蛾（Scotogramma trifolii Rottemberg）各虫态的耐寒性。［方法］利用过冷却点测定仪对旋幽夜蛾1~5龄幼虫、蛹（滞育、非滞育）和雌雄成虫分别进行过冷却点和结冰点测定。［结果］各龄幼虫过冷却点随龄期的增加逐渐升高，1龄幼虫（-13.63 ℃）〈2龄幼虫（-12.50 ℃）〈3龄幼虫（-11.08 ℃）〈4龄幼虫（-11.05 ℃）〈5龄幼虫（-10.04 ℃）。相邻龄期幼虫的过冷却点均未呈现出显著性差异，但低龄幼虫和高龄幼虫间存在显著性差异。其余虫态过冷却点滞育蛹（-24.94 ℃）显著低于非滞育蛹（-21.91 ℃），雌蛹（-23.84 ℃）〈雄蛹（-23.52 ℃），雌成虫（-15.75 ℃）〈雄成虫（-15.44 ℃），但雌雄蛹和雌雄成虫之间均未呈现显著性差异。［结论］ 旋幽夜蛾各虫态过冷却点变化为蛹（-23.67 ℃）〈成虫（-15.60 ℃）〈幼虫（-11.48 ℃），三者之间有显著性差异。研究结果为旋幽夜蛾的越冬区划提供了科学依据。

[Objective] Cold hardiness of the clover cutworm, Scotogramma trifolii Rottemberg, was investigated.[Method] The supercooling points and freezing points at each development stage of S. trifolii were measured.[Result] It showed that the supercooling points from the 1st instar to the 5rd instar larvae was increasing, the 1st instar larvae （-11.36 ℃）, the 2rd instar larvae （-12.50 ℃）, the 3rd instar larvae （-11.08 ℃）, the 4rd instar larvae （-11.05 ℃） and the 5rd instar larvae （-10.04 ℃）. There was significant difference between the low instar larvae and old instar larvae, while there was no significant difference between the adjacent instars. At the stage of pupae, the supercooling points of diapause pupae （-24.94 ℃） was significantly lower than that of nondiapause pupae （-21.91 ℃）. However, there was no significant difference between female pupae （-23.84 ℃） and male pupae （-23.52 ℃）. At the stage of adult, no significant differences were observed between females and males. [Conclusion] Significant change in the supercooling point was observed between the pupae（-23.67 ℃）, the adult（-15.60 ℃） and the larvae （-11.48 ℃）. These finding provided an important basis for determination of the overwintering regions of the clover cutworm, S. trifolii.