The Analysis Of Aerial Population Dynamics Of Ricehoppers And Rice Leaf Roller In Xiushan, Chongqing

During the research collaboration in the country, Many large alpine insect nets were established according to topographical features across the country, and were used to observe the flight dynamics of migratory insects, especially white-backed planthopper and brown planthopper. These alpine net has been revoked Since1980, only Xiushan alpine net insisted on running. Xiushan alpine net has insisted on running for more than30years Since1977, It is important for our research of the regularity of the insect migration because of Special topographic. Six kinds of insects were captured by the Xiushan alpine net include white-backed planthopper, brown planthopper, small brown planthopper, Laodelphax striatellus, Cnaphalocrocis medinalis and Cyrtorhinus lividipennis Reuter. Based on the33years (1977-2010) of data, we preliminary analyze the amount of insect-catching and air temporal dynamics of the six insects, and mainly analyzes white-backed planthopper and brown planthopper. The main results are as follows:1. Through the research of the six species of insects including the early dates of net capturing, the annual trap quantity, the trap quantity distribution of different months and the local rice cultivation conditions of Xiushan mountain, we found that:(1) Xiushan mountain net is mainly for the trap monitoring of the six species of insects, among which, Sogatella furcifera and Nilaparvata lugens occupies a large proportion, while the number of the other four kinds of insects is smaller; the insect quantity using nets of Sogatella longifurcifera and Laodelphgax striatellus presents the declining trend year by year, but that of Cnaphalocrocis medinalis Guenee is on the rise.(2) the insect quantity using nets of various kinds of insects from different months was analyzed; the journey dynamic in different months is explicit; Meanwhile, through the local rice cultivation condition and field investigation results,we can determine as follows:the early immigration stage of Sogatella furcifera is in May and June, they move to the north with southwest air curent from overseas or rice planting areas in the south; July is the main immigration stage, at that moment, the rice is at the late tillering to booting stage, when the nutrition conditions are still suitable for the needs of Nilaparvata lugens; After the late September, all of the local rice is almost harvested; the late September to middle October is the main period of moving back for Nilaparvata lugens.2. we analyzed the historical date from1977—2010based on the alpine nets of XiuShan, and we simulated source areas from the peak data in early immigration periods (in May and June) in the past33years based on HYSPLIT, then did efficient analysis of these insect source areas. The following results were obtained:(1) The effectiveness of source areas in June is more than in May, and the main northward immigration period of the white-backed planthopper is June;(2) Most of the time of flight of the white-backed planthopper in xiushan is concentrated in less than24h, and they still have the ability to continue northward migration;(3) Simulations of migration trajctories indicated that most of the early immigrants came from central and eastern of Guizhong province, northern Guangxi and the junction of Guangxi and Vietnam. The spatio-temporal distribution of source areas shifted gradually northward with the time.3. we simulated the trajectory of brown planthopper from the peak data in early immigration periods (July) and the move back periods based on HYSPLIT. The following results were obtained:(1) the early immigrants of BPH mainly concentrated in central and northern in Guangxi Province, and the spatio-temporal distribution of source areas shifted gradually northward with the time;(2) the source areas of BPH in the move back periods mainly concentrated in central and northern in Hubei Province, the junction of Hubei and Hunan and Northeastern Hunan Province.4. we compiled the historical date of small brown planthopper and cnaphalocrocis medinalis Guenee, and simulated the trajectory with the peak data. The following results were obtained:(1) the time of SBPH captured by alpine net Mainly concentrated in July and August, the proportion were respective42.87%and21.43%;(2) the time of cnaphalocrocis medinalis Guenee captured by alpine net Mainly concentrated in July, August and September, the proportion were respective16%.62%and16%.