棉田小枕异绒螨幼螨空间格局及抽样技术研究

STUDIES ON THE SPATIAL PATTERN OF ALLOTHROMBIUM PULUINUM NYMPHS IN COTTON FIELD AND ITS SAMPLING TECHNIQUE

本文通过聚集度指标(包括:C、Ⅰ、C_A、Ⅰ_δ、M/(?)和L/1+(?))测定和Iwao's M-x线性回归模型及其改进模型以及Taylor's幂法则的分析。结果表明棉田小枕异绒螨幼螨个体间相互吸引,其空间格局的基本成分是个体群(α>0,α′>0),在低密度下,个体群呈聚集格局(C>1,Ⅰ>0,C_A>0,Ⅰ_δ>1,M/x>1,L/1+(?)>1,β>1,β′>1),且隶属于具有一个公共K_c(=0.3015)值的负二项分布(α>0且β>1);其聚集速率随种群密度的提高而下降(γ<0)。但在一切密度下,其聚集强度随种群密度提高而加强(a>1且b>1)。棉田小枕异绒螨幼螨最适理论抽样数由n=1/D^2·(1/(?)+3.3170)给出,其种群平均密度由x=0.3015(P_0^(-3.3170)-1)估计。

The measuring methods of the indices of aggregation intensity (including: C, I, C_A, I_δ, M/x and L/1+x) and the analysis of model of Iwao's M-x straight line regression and the model of improved Iwao's M-x curve line regrssion, and Taylor's power rules were used, in this papre to analyse the spatial pattern of Allothrombium puluinum Ewing larvae in different cotton fields in different stages. The results showed that the relationship of M-x of A. puluinum Ewing larvae population in contton field was a quadrat regression equation. Under lower density, the basic component of the spatial pattern of A. puluinum Ewing larvae population was a loose individual group (α>0 or α′>0) in which individual group was aggregation pattern (β>1 or β′>1), and it was subordinate to negative binomial distribution witha common Kc(=0.3015). The relative aggregation rate decreased with increase of the population density(γ<0). But under all density, the aggregation degree raised with increase of the populaton density (a>1 and b>1). The number of the most suitable theoretical sampling of A. puluinum Ewing larvae in cotton field were given by the n=1/D^+2·(1/x+3.3170). And the mean density of the population were estimated by the x=0.3015(P_0^(-3.3170)-1). Where in: the number of most suitable theoretical sampling, D: the allowable error, and P_0: the probability of 'zero' sample squares.