【摘要】 【目的】草地螟Loxostege sticticalis L.具有间歇性猖獗的特点。本研究旨在揭示我国草地螟第2和3个暴发周期结束的原因,以加深对草地螟间歇性猖獗机理的认识。【方法】利用轨迹分析方法,分析1983和2009年草地螟成虫的迁飞动态;通过计算气温距平、降雨量距平百分率,探索影响种群波动的气候背景;利用月平均再分析资料,分析异常气候条件的大气环流背景。【结果】1983年6月我国东北及俄罗斯东西伯利亚地区出现极端低温多雨天气,而我国华北北部出现严重的干旱,引发了大范围的草地螟种群崩溃事件。1983年秋季,集中越冬区仅局限在山西北部的高海拔地区。山西北部天敌寄生率在1984年春天达到较高的水平,进一步压低了草地螟种群的数量,导致第2个发生周期的结束。2009年6月东北亚地区出现了与1983年6月类似的极端恶劣气候,致使我国东北、华北以及俄罗斯东西伯利亚、远东地区再次出现大范围的草地螟种群崩溃事件,直接导致第3个周期的结束。大气环流异常是这两次极端气候事件的直接原因。【结论】极端气候事件已成为我国草地螟发生周期结束的重要因素。鉴于极端气候的出现具有很大的不确定性,我国草地螟发生周期的结束目前尚难以实现长期预测。更多还原

【Abstract】 【Aim】The meadow moth,Loxostege sticticalis L.,exhibits intermittent population dynamics.This study aims to reveal the causes for the termination of the 2nd and 3rd outbreak periods of L.sticticalis in China. 【Methods】We analyzed the migration dynamics of L. sticticalis in 1983 and 2009 using trajectory analysis,explored the climatic background of population fluctuation by calculating anomalies of temperature and precipitation and checking the atmospheric circulation background responsible for abnormal climatic condition. 【Results 】 In June of 1983,extremely low temperature and excessive precipitation occurred in Northeast China and East Siberia of Russia,and severe drought occurred in North China,resulting in a large-scale population collapse event of L. sticticalis with the overwintering area being limited within the high-altitude area in northern Shanxi province in autumn of 1983. The parasitism rate of natural enemies in northern Shanxi province reached a rather high level in spring of 1984,further suppressing the population of L. sticticalis,and leading to the termination of the 2nd outbreak period. In June of 2009,Northeast Asia experienced extremely bad climate similar to that in June of 1983,and then a large-scale population collapse event of L. sticticalis occurred again in Northeast China,North China,and East Siberia and Far East of Russia,resulting in the termination of the 3rd outbreak period.Abnormal atmospheric circulation pattern was the direct cause of these two extreme climate events.【Conclusion】Extreme climate event has become an important factor causing the termination of outbreak periods of L. sticticalis in China. Due to large uncertainty of extreme climate event,long-term prediction for the termination of outbreak periods of the meadow moth in China is difficult to be made in the current stage.更多还原