Tracing The Geographic Origin Of The Long Distance Migration Of Nilaparvata Lusens (Stal)Using Multi-stable Isotopes Analysis

The brown planthopper Nilaparvata lugens (Stal) is a long-distance migration of insect that is considered as an important pest of rice. Its outbreak caused great threats on the growth of rice, and resulting in serious loss of agricultural economy.The purposes of this study were to indentify geographical characteristics of the stable isotope ratios, H, O, C and N in Nilaparvata lugens samples collected from17geographical origins in the southern of China by multi-stable isotope analysis, variance analysis were utilized to determine geographical variations of stable isotope ratios among different geographical origins of Nilapai-vata lugens samples, and the the use of trend surface analysis to explore the geographic distribution characteristics of stable isotope ratios, as well as the application of linear discriminant analysis, which allowed classification and discrimination of the Nilapai’vata lugens samples from different geographical population, to provide a basis for future research on tracing migration route of Nilapai-vata lugens. The main results of this study are as follows:1. The stable isotope ratios, H, O, C and N of Nilaparvata lugens samples collected from different regions were determined by isotope ratio mass spectrometer (IRMS). H, O, C and N stable isotope ratios varies in different geographical origins of Nilaparvata lugens, it ranges from-245.24‰to-169.88‰,15.43‰to19.75‰,-30.06‰to-28.29‰,1.11‰to6.61‰separately. The analysis of variance of general linear model showed that H, O, C and N stable isotope ratios all have significant differences among the different regions.2. The4stable isotope ratio data of Nilaparvata lugens samples from different regions were analyzed by trend surface analysis to study theirs geographical distribution characteristics. The results shown that the trend surface regression equation can reveal the geographical distribution characteristics of H stable isotope ratios. The distribution trend of82H of Nilaparvata lugens populations is decreasing from the southeast coast to the northwest inland in the southern of China, which is inconcidence with the geographical distribution trend of H in precipitation in theory. But O, C and N stable isotope ratios of the trend surface fitting results are not significant, the distribution of these types of elements have not close relationships with latitude and longitude.3. In this study,4kinds of stable isotope ratio data of52Nilaparvata lugens samples collected from17different regions were analyzed by linear discriminant analysis, and discriminant function was established according to the data to predicting and verifying the known samples, the result shown that the overall chassification success was80.8%.In summary, this study discussed the H, O, C and N stable isotope composition characteristics of Nilaparvata lugens from different geographical sources, and conducted a feasibility study on the use of stable isotopes to identify the different geographical populations of brown planthopper. This kinetic model should provide significance reference for studies of other migratary insect and its geographical environment.