3种共同危害沙棘的害虫的空间分布格局研究

沙棘是中国干旱和半干旱地区水土保持林中的重要树种，陕西省吴起县人工种植的沙棘受到钻蛀害虫沙棘木蠹蛾、红缘天牛和食叶害虫栎黄枯叶蛾的共同危害。为研究3种害虫的危害特性，利用地统计学方法分析不同受害程度沙棘纯林内沙棘木蠹蛾幼虫、红缘天牛幼虫及羽化孔、栎黄枯叶蛾茧的空间分布特性。通过全方向的变异函数曲线图分析得知，不同受害沙棘纯林中沙棘木蠹蛾幼虫、红缘天牛幼虫及羽化孔、栎黄枯叶蛾茧均呈聚集分布。其中，沙棘木蠹蛾幼虫、红缘天牛羽化孔的空间依赖范围在重度受害林分中为5.900和7.800 m，低于轻度受害林分的10.460和12.290 m，而局部空间连续性在重度受害林分中为63.7%和73.3%，高于轻度受害林分的51.0%和69.1%，其余虫态的空间依赖性和局部空间连续性在不同受害林分中近似。由空间分布图和相关性分析得出，栎黄枯叶蛾茧的分布具有边缘效应，与其余2种钻蛀性害虫的分布没有显著的相关性；红缘天牛幼虫的分布与红缘天牛羽化孔及沙棘木蠹蛾幼虫的分布无显著的相关性；沙棘木蠹蛾幼虫的分布与红缘天牛羽化孔的分布具有显著的正相关性。基于变异函数和相关性分析，笔者探讨了沙棘上栎黄枯叶蛾、红缘天牛及沙棘木蠹蛾三者之间的危害关系，明确了沙棘木蠹蛾与红缘天牛是偏利共存的关系，为实现综合管理提供理论依据。

Research on the Spatial Distribution Pattern of Three Kinds of Insect Pests on Hippophae rhamnoides ssp. sinensis

Sea buckthorn, Hippophae rhamnoides ssp. sinensis is generally regarded as the most valuable species for the conservation of soil and water in arid and semi-arid regions of China, it was heavily damaged by Holcocerus hippophaecolus, Asias halodendri Pallas and Trabala vishnou gigantina Yang in pure man-made sea buckthorn forests in Wuqi County, Shaanxi Province. In order to study the spatial distribution pattern of the three kinds of insect pests and explore damage characteristics of them, the spatial characteristics of H. hippophaecolus larvae, the emerging hole and larvae of A. halodendri Pallas, the cocoon of T. vishnou gigantina Yang were analyzed by using geostatistical methods in two pure man-made sea buckthorn forest, which at different damage levels. Analysis of the isotropic variogram indicated that aggregation distribution pattern of H. hippophaecolus larvae, the emerging hole and larvae of A. halodendri Pallas, cocoon of T. vishnou gigantina Yang were observed in the lightly-infested level and heavily-infested level of sea buckthorn forests. Among them, the distance of spatial dependences of H. hippophaecolus larvae and the emerging hole of A. halodendri Pallas in the heavily-infested level of sea buckthorn forest were 5.900 meter and 7.800 meter, lower than 10.460 meter and 12.290 meter in the lightly-infested forest, meanwhile, the intensities of local spatial continuity in the heavily-infested level of sea buckthorn forest were 63.7% and 73.3%, higher than 51.0% and 69.1% in the lightly-infested forest. Besides, the rest of the indexes were approximate in different damage levels of forests. Analysis based on overlay maps and correlation analysis indicated that the cocoon of T. vishnou gigantina had a clustered distribution at the edge of the plantation, but it didn’t have significant correlation with the two boring insects; A. halodendri larvae had no obvious relationship with the emerging hole of A. halodendri and H. hippophaecolus larvae. However, there was a significant positive correlation between the distribution of H. hippophaecolus larvae and the emerging hole of A. halodendri Pallas. Based on isotropic variogram and correlation analysis, the study explored the relationship among H. hippophaecolus, A. halodendri Pallas and T. vishnou gigantina Yang, it indicated that H. hippophaecolus had a characteristic of commensalisms with A. halodendri, and provided a theoretical basis for integrated management.