桐花树毛颚小卷蛾幼虫空间分布型及抽样技术

Spatial Distribution Pattern and Sampling Technique of Lasiognatha cellifera Larvae

通过5种聚集度指标以及Iwao法的m^*-m直线回归法和Taylor法的幂法则,对桐花树人工种植区内毛颚小卷蛾幼虫空间分布格局进行分析。结果表明:毛颚小卷蛾幼虫1年中在林间总体上呈聚集分布,仅在7月中下旬和10月中下旬呈均匀分布。Iwao的m^*-m回归方程为m^*=1.069m+1.911,显示该虫在林间呈聚集分布,分布的基本成分是个体群,个体之间存在相互吸引关系。样本平均数(m)与方差(S^2)的对数值的关系式为lgS^2=1.339lgm+0.216,显示该虫在林间呈聚集型分布,且分布具有密度依赖性,即聚集强度随种群密度的升高而相应增大。Iwao的理论抽样数公式为N=t^2(2.911/m+0.069)/D^2。

Five aggregation indexes such as diffusion coefficient(C),mean crowding(m^*) were used to analyze the spatial distribution pattern of Lasiognatha cellifera larvae.Result shows that : This pest distributed aggregately as a whole in the mangrove, except uniform distribution in mid-to-late July & in mid-to-late October,and the basic distribution component was individual population.According to Iwao's regression : m^*=1.069 m +1.911.The formula of the logarithm of the mean (m)& variance (s^2 ) is : lgS^2 =1.339lg m +0.216.The sequential sampling formula of Lasiognatha cellifera larvae are N = t^2 [2.911/ m +0.069]/ D^2 .