通过对1990—2012年云南省师宗县4—5月出现的白背飞虱灯诱高峰日进行轨迹模拟以及降虫高峰日的风场分析,得到以下结果:4月下旬,师宗上空盛行西风,白背飞虱虫源主要来自缅甸东北部,部分来自越南北部和金三角地区;5月份,西南风为盛行风向,其中上中旬的虫源地主要分布在越南西北部、老挝北部和滇西南,缅甸东北部可提供部分虫源;下旬则主要分布在滇西南,部分虫源来自越南西北部、老挝北部和缅甸东北部。对降虫高峰期的大气环流背景、峰日风温场、降雨等气象因子的分析结果表明,降水、风切变和气流垂直扰动是造成白背飞虱集中降落的主要因子。

Take-off behavior of the migratory moth Cnaphalocrocis medinalis Guenée was observed in unmated females and males 1 to 6 days after eclosion,in a climate chamber. The relationship between flight performance of emigrant and local breeding populations and adult age and sex were investigated. Simulated dusk and a self-developed observation device were used. The following results were obtained:( 1) There were significant differences in flight frequency between virgin moths of different ages. The number of take-offs was lowest during the first 24 hours after eclosion but peaked rapidly during the 2ndday.( 2) A significantly lower proportion of males than females took off for the first long distance migration under at optimum temperature and illumination conditions.( 3) C. medinalis displayed a long migration period,which meansthat their propensity and capacity to engage in such flights can be maintained for quite a long time after eclosion.( 4) The local breeding population had a significantly lower average take-off frequency than the emigrant population,but still comprised a certain proportion of emigrants. This suggests that migration is a hereditary characteristic of C. medinalis that is not lost completely even under continuous captive breeding. A certain proportion of emigrants always exists in any generation.

The population dynamics and characteristics of the white-backed planthopper Sogatella furcifera(Horvath)(WBPH) in a mixed cropping rice region in Qianshan,Anhui Province,were studied through systematic investigation of population density and female ovarian maturity from 2008 to 2010.The main causes for the generational and annual variation in population dynamics were analyzed in combination with data from daily light-trap catches and field surveys conducted since 2005.The following results were obtained:(1) WBPH had two main density peaks which occur in early August and mid September during the 3rd and 4th generations,respectively.The 3rd generation,which comprises the first peak of infestation,mainly damaged single-cropped rice fields whereas the 4th generation affected double-cropped,late-season rice fields.(2) The population characteristics of each generation of WBPH in single-cropped mid-season rice fields were different from those in double-cropped late-season rice fields.In the former,most WBPH were residents with some immigrants during the late stage of the 2nd generation and the early stage of the 3rd generation.However,during the late stage of the 3rd generation they were be mostly immigrants with a few residents.In contrast,in double-cropped late-season rice fields,the population was comprised predominantly of immigrants during the late stage of the 3rd generation and the early stage of the 4th generation.These insects bred and developed before finally emigrating during the late stage of the 4th generation.(3) The number of early immigrants was the key factor determining fluctuations in the abundance of the 2nd and 3rd generation,and the proportion of 3rd generation residents,in single cropped mid-season rice,and appears to be the key factor influencing population size in double-cropped late-season rice fields.Meteorological factors,such as rainfall and temperature,play an important part in determining the emigration or retention of the 3rd generation.

Qianshan County is located in southwest Anhui Province and is important to the northward and southward migration of the white-backed planthopper Sogatella fiucifera(Horváth)(WBPH) because it is both the area in which spring migrants settle and the source area for autumn emigrants.Understanding WBPH population processes in Qianshan will therefore provide scientific and technical support for regional forecasting and source suppression.Source areas of six immigration peaks of WBPH in Qianshan in 2009 and the formation of immigrant populations were analyzed using HYSPLIT,trajectory analysis software for the simulation of migration pathways,and MICAPS(Meteorological Information Compiling,Analyzing and Processing System).The population dynamics and characteristics of WBPH were studied by systematic field surveys and dissection of female ovaries.The following results were obtained:(1) The source areas of WBPH immigrants in Qianshan were,in early June western Jiangxi and the juncture between Hunan and Jiangxi(27.2°-28.7°N),in mid and late June,southern and southeastern Hunan(25.1°-26.7°N),in early and late July,eastern Hunan and Jiangxi(27.1°-28.5°N),in mid July,southeastern Hunan and southern Jiangxi(25.5°-26.8°N),and from the end of July to the beginning of August,northern and northwestern Jiangxi(28.1°-29.4°N).(2) The period of damage inflicted by WBPH on mid-season rice and late-season rice was extended by the massive retained population in 2009 which provided sufficient recruits to migrate back to source areas.(3) The population characteristics of each generation of WBPH in mid and late-season rice were determined by their ovarian developmental.The immigrants developed in mid-season rice,and most of the newly emerged adults(the 3rd generation) were trapped and retained by successive rainy days from late July to early August.These therefore stayed on the mid-season rice crops before latter moving to late-season crops to breed(late August to mid September).It was the 4th generation that migrated back to the south and the 5th generation of residents became victims of the coming winter.