杨树云斑天牛幼虫空间分布格局及生息坑道

应用聚集度指标法、回归分析法对危害南抗杨的云斑天牛幼虫种群空间分布格局进行研究。结果表明,云斑天牛幼虫在桦树林内呈聚集型分布状态,分布的基本成分为个体群,个体之间相互吸引又保持一定的排斥距离;根据距离干基部的不同位置划分为3个高度,得出不同高度的虫口数量在5%水平达显著差异,且1 m以下的虫口数量最大;云斑天牛刻槽数量与胸径大小和树高的关系中,胸径大小对刻槽数量作用率高;从树皮厚度与刻槽数量关系中可以看出3.6~4.0 mm范围内刻槽数量最多,而在单位体积的树干内,虫口密度越小其生息坑道的面积和长度越大。

A Study on the Spatial Distribution Pattern and the Living-inhabiting Tunnel of the Larvae of Batocera horsfieldi (Hope)

The aggregation index method and regressive model analysis method were used to make a study on the spatial distribution pattern of the larvae of Batocera horsfieldi which do harm to Populus delteides.cv.nankang.The results showed that the spatial distribution pattern of the larvae of Batocera horsfieldi(Hope) accorded with assemble distribution type in the Populus forest,and the basic distribution component was individual colony.Within each colony,the individuals attracted each other and kept maintaining certain repel distance.Significant difference existed at the level of 5% in the quantity of the pests at different positions if three different positions away from the base of trunk were divided.What's more,the number of the pests would be a maximum from 1 m down to zero.In the relationship between the number of gnawing nidus and DBH size and height,the DBH size greatly affected the number of gnawing nidus of Batocera horsfieldi(Hope).In the light of the relationships between the thickness of the bark and the number of gnawing nidus,it was found that the number of gnawing nidus reached the maximum when the thickness of the bark was from 3.6 mm to 4 mm.In the trunk per unit volume,the smaller the population-density of the pests was,the larger and the longer the area and the length of their living-inhabiting tunnels are.