桃一点叶蝉及其天敌草间小黑蛛种群三维空间格局动态

对桃树树冠上、中、下3层及东、西、南、北4个方位桃一点叶蝉及其天敌草间小黑蛛的系统调查分析表明,桃一点叶蝉及其天敌草间小黑蛛种群在7个部位的聚集强度其5个判断指数都大于聚集格局的判断标准,证明桃一点叶蝉及其天敌草间小黑蛛种群7个部位均为聚集格局,Iwao公式m=α+βχ中的α值均大于0,表明个体间互相吸引,其中树冠中层和东面树冠平均拥挤度最高,而树冠下层和南面树冠最低,在时间上平均拥挤度为9月中旬最高。

Three-dimentional distribution pattern dynamics of Erythroneura sudra and its natural enemy Erigonidum graminicola

Investigations on the Erythroneur sudra and Erigonidum graminicola populations in three layers (upper, middle and lower) and four directions (east, south, west and north) of peach tree crown showed that both of them had aggregated spatial distributions in these 7 part, because 5 parameters used to analyze the distribution reached required standard.Each insect was attracted by the others, as the parameter (a) in Iwao formulation m^*= a +Bx-(1971) was positive.The average density of aggregation was the biggest in its middle layer and east direction, and the smallest in its lower layer and south direction .The biggest average density of aggregation appeared in mid-September.