云斑天牛幼虫空间分布格局的地统计学分析

云斑天牛(Batocera horsfieldi)是我国重要的蛀干害虫，研究云斑天牛幼虫种群空间格局，可进一步阐释其爆发的机制并制定相对应的虫害防治策略。利用地统计学方法分析了3块白蜡林分内云斑天牛幼虫的空间分布特征，根据其有虫株率分为轻度（8.8%）、中度（22.7%）和重度（32.7%）危害林。云斑天牛幼虫在白蜡林中主要集聚分布在1 m以下的高度（75.0%），且随受害程度增强幼虫在1 m以上的分布量会增多。通过全方向的变异函数曲线图分析可得:轻度、中度和重度危害林分中，云斑天牛幼虫的空间依赖范围分别为6.412、7.821 m和7.623 m，空间变异值分别为0.641、0.894、0.907。轻度受害林、中度受害林与重度受害林内云斑天牛幼虫种群空间分布最优拟合模型分别为球状模型、指数模型和高斯模型，均呈现较明显的空间聚集性。

Geostistical Analysis on Spatial Distribution Pattern of the Larvae of Batocera horsfieldi

Batocera horsfieldi was one of the most important stem-borer injurious insect in China, studies on the spatial distribution of the larvae would further explain the mechanism of its outbreak and make effective control measures. Using geostatistics methods, we investigated the spatial distribution of the larvae of B. horsfieldi in Fraxinus chinensis forest. The forests were divided into three types based on the number of larvae found in each tree: lightly-infested (8.8％) medium-infested (22.7％), and heavily-infested (32.7％) forests. The larvae preferred to concentrate in the spaces of the tree height less than 1 m, however, it would be more than 1 m in the heavily-infested trees. Analysis of isotropic variograms indicated that the distances of the spatial dependence of the larvae for lightly-, medium-, and heavily-infested forests were 6.412,7.821 m and 7.623 m, respectively, and the related intensities of local spatial continuity were 0.641, 0.894, and 0.907, respectively. Spherical, exponential and Gaussian models were suitable ones for the simulation of the spatial distribution of B. horsfieldi larvae in F. chinensis forest. The models all exhibited significant aggregation distribution.