八点广翅蜡蝉与其天敌空间关系的聚块样方方差分析

Spatial relationship between Ricania speculum and its natural enemies based on the square variance analysis of cluster samples

【目的】分析在不同聚块大小条件下,天敌对八点广翅蜡蝉Ricania speculum(Walker)空间上跟随关系的密切程度、聚集原因和聚集范围,为评价八点广翅蜡蝉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指数法对安徽省合肥市白毫早茶园不同大小聚块条件下的八点广翅蜡蝉及其7种蜘蛛类天敌进行分析。【结果】八点广翅蜡蝉与其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,与八点广翅蜡蝉空间上跟随关系密切的天敌依次是草间小黑蛛Erigonidium graminicolum(0.781 1)、粽管巢蛛Clubiona japonicola(0.692 8)和茶色新圆蛛Neoscona theisi(0.688 7)。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时之间的八点广翅蜡蝉及其天敌的空间分布聚集程度差异均不显著。八点广翅蜡蝉的种群聚集均数λ多数情况均大于2,其聚集是该虫本身原因引起的,天敌和八点广翅蜡蝉的种群聚集均数λ绝对值均随聚块内基本样方数的增加,则种群聚集均数λ的绝对值不断增大。【结论】用八点广翅蜡蝉不同大小聚块的ρ指数判断个体群聚集时的最小范围是聚块中有4个基本样方。这为该虫抽样时确定样方大小提供科学依据。

[Objectives] To analyze the spatial relationships between Ricania speculum and seven spider species under different block size conditions.[Methods] Block square variance analysis, grey correlation, spatial aggregation intensity index, population aggregation mean and the ρ index were used to analyze the spatial distribution of R. speculum and the seven spider species in the Baihaozao tea garden, Hefei, Anhui Province.[Result] Correlations between the peak of the mean square deviation of seven spider species and R. speculum indicated that the latter had the closest spatial relationship to Erigonidium graminicolum(0.781 1), Clubiona japonicola(0.692 8)and Neoscona theisi(0.688 7). When the basic block sample number, K, was 1, 2, 4 or 8, the diffusion coefficient C increased continuously with increasing number of basic samples in the cluster, then decreased continuously in a uniform and random manner. There was no significant difference in the spatial distribution of R. speculum and the spider species when the basic sample number K in the cluster was 2, 4, 8 or 1. The population aggregation of Ricania speculum was in most cases > 2 and the result of intraspecific factors alone. When the population aggregation mean,λ, was positive, that of the spider species and R. speculum increased with increasing basic sample number in the agglomeration. The minimum range of the aggregation of individual clusters of R. speculum as determined by the clustering method indicated a minimum of four basic samples in each cluster.[Conclusion] The results provide a scientific basis for determining the optimum sample size for sampling Ricania speculum and its natural enemies.