Effects of cooling rate and repeated freezing and thawing on determination of supercooling point in chouioia cunea | 降温速率和反复冻融对白蛾周氏啮小蜂过冷却点测定的影响

Chinese. 白蛾周氏啮小蜂(Chouioia cuneaYang)是防治美国白蛾的重要天敌,为研究其耐寒性,采用不同的降温速率和反复冻融的方法对其老熟幼虫的耐寒性生理指标过冷却点(SCP)和冰点(FP)进行了测定,并以其替代寄主柞蚕(Antheraea pernyi Guérin-Méneville)和黄粉甲(Tenebrio molitor Linnaeus)做为参照。结果表明:白蛾周氏啮小蜂及黄粉甲虫老熟幼虫在0.1～15.0℃•min-1降温范围内均可有效地测定出SCP与FP,其SCP分别为(-18.44±0.93)℃和(-8.16±3.15)℃,FP分别为(-14.27±1.25)℃和(-2.19±2.03)℃;试验还发现白蛾周氏啮小蜂老熟幼虫、黄粉甲老熟幼虫和柞蚕蛹的过冷却点与冰点均能进行反复冻融测定,且冻融的前3个循环的数值差异不显著(α=0.05),3种昆虫在反复冻融后仍能保持一定的抗寒生理特征,为进一步研究其耐寒机理提供了参考。

English. Hyphantria cunea were effectively controlled by using Chouioia cunea as a natural enemy.In order to determine cold-resistance indices of the mature larvae of Chouioia cunea,,the supercooling point and freezing point were tested with reference to substitute host Tenebrio molitor and Antheraea pernyi by using the different cooling rate and repeated freeze-thaw methods.The results showed that the supercooling point and freezing point measurements on the mature larvae of Chouioia cunea and Tenebrio molitor in the cooling rate range from 0.1℃•min-1 to 15.0℃•min-1,the supercooling point were(-18.44±0.93)℃ and(-8.16±3.15)℃,the freezing point were(-14.27±1.25)℃ and(-2.19±2.03)℃,respectively.It was found that the supercooling point and freezing point of the mature larvae of Chouioia cunea,Tenebrio molitor and the pupae of Antheraea pernyi was determinated in repeated freeze-thaw,no obvious difference was found in the first three cycles of repeated freeze-thaw.They still maintained a stable cold resistance of physiological characteristics after being repeated freeze-thaw,this provides a basis for study on cold resistance mechanism.