草地贪夜蛾室内种群过冷却点和结冰点的测定

Determination of Supercooling Point and Freezing Point of Laboratory Populations of Spodoptera Frugiperda

为探明草地贪夜蛾的抗寒能力,为草地贪夜蛾的越冬区划分和综合防治提供参考.以草地贪夜蛾的室内饲养种群为例,对部分虫态进行过冷却点和结冰点的测定.结果表明,草地贪夜蛾不同虫态的过冷却点和结冰点之间存在显著差异,其中,蛹的数值最低,过冷却点为(-18.46±0.55)℃,结冰点为(-13.11±0.64)℃.3~6龄幼虫,随着龄期的增大,过冷却点和结冰点增大,3龄幼虫的过冷却点为(-11.94±0.35)℃,结冰点为(-8.55±0.57)℃,在所测部分龄期幼虫中的数值最低;6龄幼虫的数值最高,过冷却点为(-6.26±0.30)℃,结冰点为(-4.02±0.25)℃;预蛹的过冷却点和结冰点分别为(-11.35±0.48)℃,(-6.46±0.55)℃.雌成虫和雄成虫之间,过冷却点差异不显著(d_(f)=38,t=1.091,P=0.282),但结冰点差异显著(d_(f)=38,t=2.306,P=0.027).草地贪夜蛾不同发育时期个体的过冷却点和结冰点存在差异,蛹的过冷却点和结冰点分布范围较宽.

In order to explore the cold tolerance of spodoptera frugiperda,and provide a theoretical basis for the division of wintering areas and comprehensive control of spodoptera frugiperda,the supercooling point and freezing point of some insect states were determined by taking the laboratory populations of spodoptera frugiperda as an example.The results show that there are significant differences between the supercooling points and freezing points of different stages of spodoptera frugiperda,among which the pupae have the lowest values with the supercooling point of(-18.46±0.55)℃,and the freezing point of(-13.11±0.64)℃.The supercooling point and freezing point of the 3-6 instar larvae increase with the increase of instar.The supercooling point of the 3rd instar larvae is(-11.94±0.35)℃,and the freezing point is(-8.55±0.57)℃,which is the lowest value among some larvae measured.The value of 6th instar larvae is the highest,with the measured supercooling point of(-6.26±0.30)°C and freezing point of(-4.02±0.25)°C.The supercooling point and freezing point of prepupa were(-11.35±0.48)℃and(-6.46±0.55)℃respectively.There is no significant difference in the supercooling points between female and male adults(d_(f)=38,t=1.091,P=0.282),but there is significant difference in freezing point(d_(f)=38,t=2.306,P=0.027<0.05).The supercooling point and freezing point of spodoptera frugiperda in different developmental stages are different,and the distribution range of supercooling point and freezing point of pupa is the widest.