桑蓟马在桑树中空间分布的研究

桑蓟马Pseudodendrothrips mori是桑树的一种主要害虫。它的寄生直接影响供桑叶的质量和产量。我们通过泰勒幂法则和Morisita的散度指标对桑树蓟马在植株和桑园内的空间分布进行检验,结果显示:P.mori种群在植株内和桑园里的分布都存在局部化。桑树中蓟马的分布在树内显示出幼虫蓟马位于低层(从上面叶子起5-10层),但成虫更喜欢上层(从上面叶子起1-5层)。同一植株叶子的不同方向上蓟马密度没有出现明显变化。桑园内蓟马主要分布在桑园东部、南部和北部的植株上,中部,西部植株上的蓟马密度较低。P.mori的成虫和幼虫在叶子上的分布呈现明显聚集化。

Spatial Distribution of Mulberry Thrips, Pseudodendrothrips mori Niwa (Thysanoptera: Thripidae)

Pseudodendrothrips mori is a serious pest to mulberry trees and its infestation affects the qualitative and quantitative characteristics of mulberry leaves consumed by silkworm.The spatial distribution of mulberry thrips within plant and orchard was assessed using Taylor's power law and Morisita's index of dispersion.The results showed that P.mori populations were localized in certain parts of the trees and fields.Distribution of thrips within plant showed that the larval instars were located on lower canopy(leaves 5-10 from top)of trees but adults preferred the upper canopy(leaves 1-5 from top).The thrips density did not vary significantly among the leaf direction inside the trees.The thrips tended to be more accumulated on the trees located in East,South and North than in Center and West of orchard.The distributions of P.mori adults and larvae on the leaves were aggregated.