降香黄檀林灰卷裙夜蛾幼虫空间分布型研究

Study on the Spatial Distribution Pattern of Plecoptera subpallida (Walker) Larval on Dalbergia odorifera T.C.Chen

为了研究灰卷裙夜蛾在降香黄檀林内的空间分布情况,调查了广西国有高峰林场长客分场降香黄檀林受害情况和虫口密度,应用扩散系数(C)、平均拥挤度(m *)等8种聚集度指标分析灰卷裙夜蛾空间分布型。结果表明,该虫在降香黄檀林中的空间分布类型为聚集分布,通过计算聚集参数λ,分析出灰卷裙夜蛾的聚集原因是由于自身的生活习性和环境因素中的一个方面,或是由于2个因素共同作用导致的。在此基础上,建立了该虫林间理论抽样数公式:N=3.841 6×[2.229 2/m+1.589 2]/D 2 ,计算出不同虫口密度下及其不同误差条件下的最适理论抽样数。

In order to investigate the spatial distribution of Plecoptera subpallida (Walker), it was studied by six aggregation indices of diffusion coefficient( C ),mean crowding (m *) and so on in Dalbergia odorifera T.C.Chen forest of Gaofeng forest farm. The results showed that the spatial distribution pattern was assembly distribution. The aggregation was caused by one of its behavior and environment or both its behavior and environment. Based on this distribution pattern, the model was proposed which was N=3.841 6×[2.229 2/m+1.589 2]/D 2 . Meanwhile, the optimum theoretical sampling number in requirement of diffrent population density and error was also determined.