陕北烟田多异瓢虫空间分布型与抽样技术研究

根据1995年烟田多异瓢虫Hippodamiavariegats（Goeze）调查，计算了6种分布型指数，以及频次拟合优度检验，结果表明：该虫幼虫、蛹在陕北烟田里聚集分布，其聚集强度随种群密度增加而降低，聚集原因是环境差异；卵块分布同时具有聚集和随机的趋势，成虫为随机分布。同时建立了各虫态的理论抽样量公式，估测种群密度公式。

Spatial distribution patterns and sampling techniques of Hippodarnia variegata (Goeze) on the tobacco fields in northern shaanxi

Based on the prilindmp survey of Hippodamia vartegata (Goeze) in 1995, sevend methods were used to test the sghal distribution patterns of Hippodamia vartegata (Goeze) in tobeco fields. The results are as folows: 1. The spatial distribution patterns are apgregthed in larvae and pupae, in aduts are at random, in eggs are between aggregare and random. 2. The reason of aggregare is the difference of environmenL mally relared with the distribution of mpzus persicae. 3. The apgregate grade of larvas and pupae is 'decreased with the density increasing, and of eggs are influenced a fittie by its density. 4. The formulae of Iwao's sampling and population density for larvae, eggs and pupae are established.