桑皱鞘叶甲幼虫空间格局的研究

Spatial Distribution Pattern of Larvae of Abirus fortunei (Baly) (Coleoptera:Eumolpidae)

通过对杂交桑和桑湖桑园皱鞘叶甲幼虫在土层下的分布状况进行调查和分析 ,确定了该幼虫的空间分布符合负二项分布 ,其图式为聚集的 ,分布的基本成份是个体群。该幼虫在土层的垂直分布以 31～ 5 0cm深处最多 ,分别占杂交桑和湖桑的 70 .4%和 6 2 .1 % ,其次为 1 1～ 30cm深处 ,占 2 6 .5 %和 2 6 .1 %。幼虫调查的最适抽样数N与平均虫口密度m及相对误差D的关系为 :N =1 /D2 (2 .81 7/m +0 .990 6 )。

The underground disribution of the larvae of Abirus fortunei (Baly) in hybrid mulberry fields and common mulberry fields were investigated. The results showed that the spatial distribution of the beetles conformed to negative binomial distribution, the spatial pattern was an aggregative one, and the basic component of distribution was the colony. 70.4% and 62.1% of the larvae were found 31～50cm and 11～30cm underground respectively in hybrid mulberry fields, and 62.1% and 26.1% at the same vertical ranges in common mulberry fields. A model for optimal sampling number (N), means of population density (m) and relative difference (D) was built as: N=1/D 2(2.817/m+0.9906).