沙蒿金叶甲空间分布型及抽样技术研究

沙蒿金叶甲是危害宁夏荒漠草原重要牧草——沙蒿的一种重大害虫,为进一步了解该虫暴发成灾的机理,掌握该虫生态学特性以及确定有效的田间抽样设计方案,对沙蒿金叶甲的空间分布及抽样技术进行了调查和统计分析。结果表明,沙蒿上部的沙蒿金叶甲数量显著高于中部和下部,而中部和下部间差异不显著;空间分布型适合度x2检验结果表明,沙蒿金叶甲在田间最接近负二项分布;聚集度指标检验结果表明,沙蒿金叶甲在田间沙蒿上的空间分布属聚集分布,聚集原因是由环境异质性引起的;应用Iwao的m*-m回归分析法和Toylar幂法则进一步得到证实,表明沙蒿金叶甲个体间相互吸引,分布的个体成分是个体群,且与密度有关,有密度依赖性,聚集强度随种群密度的升高而增加;拟合该虫在一定精确度水平下的最适理论抽样方程为N=[3．937 79／m+2．880 30]／D2,序贯抽样方程为Tn=3．937 79／[D2-2．880 30／n]。

Study on the spatial distribution pattern of chrysolina aeruginosa fald and its sampling technique

Chrysolina aeruginosa is one vital pest to Aytemisia sphaerocephala that is a kind of forage in desert grassland in Ningxia. Tthe spacial distribution pattern of Chrysolina aeruginosa and its sampling technique were studied in this paper in order to further grasp it epidemic ,mechanism know its ecological characteristic and decide effective sampling program. The results were as follows: the number of Chrysolina aeruginosa in the upper strata of Aytemisia sphaerocephala was more than that in the middle and lower strata significantly;the spatial distribution pattern of this insect conformed to the negative binomial distribution in field. It was also tested that the distribution pattern was aggregative by aggregation indexes, which was caused by environmental heterology. The results was further proved by the use of Toylar's and Iwao's methods that individual of Chrysolina aeruginosa attracted each other and the components of individual distribution was group. Meantime,the equations of the theoretical sampling and the sequential sampling being set up at a precision level were N=[3. 937 79/w 2. 880 30]/D2 and Tn = 3. 937 79/[D2-2.880 30/ n],respectively.