黄瓜上烟粉虱成虫种群空间分布格局及时序动态

应用6种聚集度指标和Iwao法、Taylor幂法则,考查了2006年7—8月份烟粉虱成虫种群(Bemisia tabaci)在黄瓜上的分布型;分析这些聚集度指标与密度的相关性,选择了受密度影响较小的负二项分布的k值,描述种群的时序动态。结果显示:在黄瓜的生长期间,该成虫种群聚集强度有明显的变化,水平空间为高→低→高→低,百株虫量最多为23359头,最少为1908头;垂直空间为低→高→低→高,百株第8叶烟粉虱成虫数量最多,为9093头,其次是第9叶和第7叶,分别为8488头和8353头。从该种群在黄瓜上的整个发生期来看,种群空间格局处于扩散和聚集交替进行的动态过程中。在空间分布格局研究的基础上,给出了合适的抽样数。

The Spatial Distribution Pattern and its Temporal Dynamics of Bemisia tabaci Adult Population Inhabiting on the Cucumbers

The spatial pattern of Bemisia tabaci adult population inhabiting on cucumbers was analyzed by calculating six indices of aggregation,and parameters of Iwao model and Taylor''s power law model from July to August in 2006.The correlations of different aggregate indices value with mean densities were evaluated.The k value of negative binomial distribution which was shown to be poorly correlated with densities was chosen to describe the temporal dynamics of Bemisia tabaci adult population.The results showed obvious difference was found in the intensity of aggregation of its adult population during the life span of the cucumber growth.The population on horizontal spatial changed from loosely to highly aggregated,and then to loosely,to highly aggregated again.The highest number of its adult population inhabiting on hundred cucumber plants was 23359 and the lowest was 1908.The population on vertical spatial changed from highly aggregated to loosely aggregated,and then to highly,to loosely aggregated.The largest number of B.tabaci adult individuals harbored on hundred plants was on the eighth leaf,which was 9093,and the second number was on the ninth and the seventh leaf,which were 8488 and 8353 respectively.Throughout the incidence of stage B.tabaci inhabiting on cucumbers,the spatial pattern of its population aggregated and diffused alternatively.Based on the study the spatial distribution pattern of B.tabaci adult population,the most suitable sampling intensity is established.