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长棒四节蚜小蜂是杨圆蚧的重要天敌,为一种自然控制能力很强的寄生小蜂。用频数分布法、聚集度指标法研究其空间分布型,结果表明为聚集分布,分布的基本形式系一般的负二项分布。根据 Iwao 的统计方法,利用N=1/D~2(α+1/+β-1)公式,计算在各种虫口密度下的最适抽样数。
Four long aphids wasps are the important natural enemies of the young scale, as a natural control of parasitic wasps. The frequency distribution method and the degree of aggregation index method were used to study the spatial distribution patterns. The results showed that the distribution patterns were aggregated, and the basic form of distribution was negative binomial distribution. According to the statistical method of Iwao, the optimal sampling number at various population density was calculated using the formula N = 1 / D ~ 2 (α + 1 / + β-1).