粘虫在中国西部越冬北界探讨

粘虫每年会在越冬区和非越冬区进行季节性的往返迁飞,20世纪60年代将粘虫在中国东部地区的越冬北界确定为33°N,但其在西部地区越冬的相关信息一直未见报道.为确定粘虫在中国西部33°N能否越冬,于2015年至2018年在中国西部33°N附近的汉中、安康及杨凌3个地区设置观察点展开调查.每年11月将室内饲养的粘虫末龄幼虫放...

Discussion of Overwintering North Boundary of Mythimna separate(Walker) in Western China

The Mythimna separate(Walker) migrates seasonally between overwintering and non-wintering areas every year.In the 1960s, the northern boundary of overwintering for Mythimna separate(Walker)in eastern China was 33°N, but no report was found the relevant information about its overwintering in the western region .To explore whether the Mythimna separate(Walker)can overwinter at 33°N in western China,an observation point was set up near 33°N in Hanzhong, Ankang and Yangling of western China from 2015 to 2018.The last in star larvae of Mythimna separate(Walker)reared in the laboratory were placed at the observation point in November each year, and the survival rate of Mythimna separate(Walker)was in vestigated regularly from December to March of the following year.The results showed that the overwintering survival rate of Mythimna separate(Walker)in the three areas decreased from December to March in the following year.From 2016 to 2018 in March each year, the highest survival rates of Mythimna separate(Walker) in Hanzhong area were 3.77%±0.80%, 2.33%±0.60%, 0.17%±0.17%; 4.00%±0.38%, 1.83%±1.01% in Ankang area, 1.50%±0.17%, and 0, 0.15%±0.04% and 0.63%±0.08% in Yangling area:At the end of overwintering, the highest numbers of adult Mythimna separate(Walker) that successfully emerged in Hanzhong area were 8, 9, 1; 9, 8, 4 in Ankang area; and 0, 1, 2 in Yangling area.Inconclusion, the sporadic individuals of Mythimna separate(Walker) can survive the winter at 33°N in the Shaanxi region of western China, at the same time, we found that 33°N is the boundary of overwintering of Mythimna separate(Walker) in western China for the first time.