绿盲蝽与其天敌空间关系的聚块样方方差分析

Blocked Quadrat Variance Analysis for Spatial Relationship of Lygus lucorum and Its Natural Enemies

【目的】分析在不同聚块大小条件下,蜘蛛类天敌对绿盲蝽Lygus lucorum空间上跟随关系的密切程度、聚集原因和聚集范围,为评价绿盲蝽的天敌优势种提供科学依据。【方法】用聚块样方方差分析法、灰色关联度法、空间聚集强度指数、种群聚集均数法和ρ指数法对不同大小聚块条件下的绿盲蝽及其7种蜘蛛空间格局进行分析。【结果】绿盲蝽与其7种蜘蛛类天敌均方差峰值时的聚块样方数的关联度分析结果表明:与绿盲蝽空间上跟随关系密切的前三位天敌依次是茶色新圆蛛Neoscona theisi、粽管巢蛛Clubiona japonicola和草间小黑蛛Erigonidium graminicolum。在聚块内基本样方数K为1、2、4、8时,随着聚块内基本样方数的增多,聚集分布格局时的扩散系数C不断增大,均匀和随机格局时扩散系数不断减小。聚块内基本样方数K为2、4、8时与K为1时之间的绿盲蝽及其天敌的空间分布聚集程度差异均不显著。绿盲蝽的种群聚集均数λ多数情况均大于2,其聚集是该虫本身原因引起的,天敌和绿盲蝽在种群聚集均数λ为正值时,随着聚块内基本样方数的增加,则种群聚集均数λ不断增大。用聚块ρ指数判断绿盲蝽个体群聚集时的最小范围是聚块中有2个基本样方。【结论】样方大小不改变绿盲蝽及其天敌的空间聚集程度。2个基本样方为绿盲蝽抽样调查的最佳样方大小。本研究结果为绿盲蝽及天敌抽样时确定样方大小提供了科学依据。

【Objective】The closeness of spatial following relationship between Lygus lucorum and seven natural spiders was analyzed systematically to provide scientific basis for evaluating dominant natural enemies of Lygus lucorum and determining the optimum quadrat size.【Method】The sampling size of quadrat of Lygus lucorum in tea garden in Hefei area,Anhui province was estimated by blocked quadrat variance analysis, grey relation analysis,aggregated-intensity index method of spatial patterns and ρ index method.【Result】The most closely followed natural enemies of Lygus lucorum were Neoscona theisi,Clubiona japonicola and Erigonidium graminicolum,with correlation degree values of 0.762 7、0.757 1 and 0.691 1,respectively. Combining the blocked quadrat variance analysis with aggregated-intensity analysis,the results showed the diffusion coefficient C-value of aggregation pattern increased with the increase of basic quadrats when there were 1、2、4 or 8 basic quadrats in the ploy-block. But as for uniform and random pattern,it was continuous decreasing. When the numbers of basic quadrat within the ploy-block were 2,4 and 8 as compared with 1,the gathering degree of spatial distribution of Lygus lucorum and its spider predators was not significant difference. In the most cases,the average λ values of Lygus lucorum were more than 2,indicating that the gathering was caused by the pest itself. When the λ values were positive,along with the increase of quadrat in the ploy-block,the gathering averages were continuously increasing. The smallest scope of individual population aggregation was evaluated by using ρ index of Lygus lucorum under different sizes of poly-blocks.As a result,the minimum area of individual population aggregation pattern of Lygus lucorum had two basic quadrats with 8 m2 in this study.【Conclusion】The size of quadrats did not change the spatial aggregation of Lygus lucorum and its natural enemies. The result indicated that the best area of the samples was 8 m2 for Lygus lucorum. This study provided a scientific basis for determining the size of quadrat on the pests sampling.