东北地区亚洲玉米螟野生滞育幼虫耐寒性研究

Cold-hardiness of diapausing wild larvae of Ostrinia furnacalis in northeastern China

为明确东北地区亚洲玉米螟Ostrinia furnacalis(Guenée)野生滞育幼虫耐寒能力和耐寒性策略,利用比较过冷却点(supercooling points,SCP)和低温存活率的方法,对东北地区7个地理种群(佳木斯、德惠、公主岭、沈阳、瓦房店、普兰店和旅顺)亚洲玉米螟野生滞育幼虫的耐寒能力和耐寒性策略进行了研究。结果表明,试虫SCP介于-6.18^-29.98℃间,7种群SCP均值介于-13.95^-25.85℃间,种群间差异显著(P<0.05),但种群SCP高低与其纬度分布无关;7种群12 h低温暴露死亡率随纬度升高而降低,差异显著(P<0.05),其致死中温(LT50)介于-52.19^-68.19℃间,LT50亦随纬度升高而降低,种群间差异显著(P<0.05);试虫-30℃以上低温暴露12h无死亡,-30℃以下处理后死亡率随温度降低而升高,-80℃冷冻处理12 h后仍有部分能够复苏,表明东北地区亚洲玉米螟耐寒能力极强,以耐结冰的耐寒性策略越冬,SCP不能评价其耐寒性强弱,低温存活率和LT50可以作为界定其耐寒性强弱的指标。

The freeze resistance capability and cold-hardiness of the wild diapaused larvae of Asian corn borer（ACB） ,Ostrinia furnacalis（Guenée） were investigated through comparing the supercooling point （SCPs） and low temperature survival rates of seven geographical populations （Jiamusi, Dehui, Gongzhuling, Shenyang, Wafangdian, Pulandian, and Lvshun ） collected from the northeastern China. Results showed that the SCPs in the range of -6.18--29.98℃were significantly different（P〈0.05）,with an average varying from -13.95 to -25.85℃,among the geographic populations, but there was no strict correlation between the SCPs and their geographic latitudes; after 12 h cold exposed, the mortality was decreased with the increasing latitudes ,and significantly different（P〈0.05）; the Median lethal temperatures（LT50） were significantly different（P〈0.05） in the range of -52.19--68.19℃ and decreased with the increasing latitudes; after 12 h cold exposed ,the test insects were no death above the -30℃,however the mortality was increasing with the decreased temperatures below the -30℃ and after 12 h frozen, some could resuscitate at the -80℃. So we can determine that the cold-hardiness was the overwintering strategy for Asian corn borer; the cold resistance strength was no that SCP but that survival of low temperature and LT50.