草地贪夜蛾在江西省南昌市的越冬与低温驯化

Overwintering and cold acclimation of fall armyworm Spodoptera frugiperda in Nanchang,Jiangxi Province

为明确迁飞性害虫草地贪夜蛾Spodoptera frugiperda的越冬范围与潜在扩散区,通过调查野外越冬种群及模拟越冬试验分析草地贪夜蛾在江西省南昌市越冬的可能性及其相应的越冬虫态,并通过低温驯化探究草地贪夜蛾对低温的适应性进化能力。结果表明,在江西省南昌市,进入冬季后草地贪夜蛾蛹和3龄幼虫的存活时间较长,可能为草地贪夜蛾的越冬虫态;3龄幼虫可从12月初存活至第2年1月底至2月初,但无法越过完整冬天;前期的低温驯化会显著提高草地贪夜蛾3龄幼虫和6龄幼虫在极端低温(-8℃处理2 h)下的存活率,并显著缩短其在经历0℃处理12 h后的冷昏迷恢复时间,证明其具有低温驯化能力及扩散至较冷地区越冬的潜力,江西省南昌市及相近等温带可能会成为草地贪夜蛾的冬繁区。

To identify the overwintering and potential spreading area of fall armyworm Spodoptera frugiperda,the overwintering population surveys and simulated overwintering experiments were conducted,which aimed to determine whether S.frugiperda could overwinter in Nanchang City,Jiangxi Province,and its corresponding life stages.In addition,a cold acclimation experiment was designed to predict the adaptive evolution ability of S.frugiperda.The results showed that pupae and 3rd-instar larvae of S.frugiperda survived longer in Nanchang,suggesting these as potential overwintering stages.Specifically,the 3rd-instar larvae survived from early December to late January or early February but couldn’t pass the entire winter.Survival rates of S.frugiperda larvae treated by-8℃for 2 h signifi cantly improved,and the recovery time after chill coma(induced by 0℃for 12 h)significantly shortened with cold acclimation,demonstrating the cold acclimation ability of S.frugiperda and its potential to spread to colder areas for overwintering.Therefore,caution is required to prevent Nanchang and its isotemperate zones from becoming winter breeding areas for S.frugiperda.