美国薄壳山核桃警根瘤蚜的空间分布

警根瘤蚜是危害薄壳山核桃嫩叶的重要害虫之一。运用扩散系数、丛生指标、Morisita扩散型指数等7个常见的聚集度指标,分别对南京苗圃地的1年生与2～3年生美国薄壳山核桃苗上警根瘤蚜的空间分布格局进行了研究,并用Iwao的m*-m回归分析法进行验证,还运用种群聚集均数概念分析警根瘤蚜的聚集度原因。结果表明,警根瘤蚜在2～3年生和1年生薄壳山核桃上虫瘿的分布型都呈聚集分布,但聚集原因是不同的。其在2～3年生薄壳山核桃上聚集是由昆虫本身特性或由其本身生物学特性与环境异质性两种因素共同作用而导致; 在1年生薄壳山核桃上个体聚集的原因是由某些环境因子引起。
Phylloxera notabili(Pergande)is one of the important pests on browses of Caraya illinoensis. The spatial distribution of the P.notabili on 1-age and 2-3-age trees of C. illinoensis were studied at a nursery in Nanjing. Seven indexes of aggregation including diffusion coefficient, clustered index, Morisita diffusion index and so on were applied to analyze the spatial distribution of P.notabilis, and results were verified with m*-m regression analysis of Iwao. In addition, concepts of population aggregation average were used to analyze the reason of accumulative degree on P.notabili. The results showed that the spatial distribution of P.notabilis among 2-3-age trees and 1-age trees were all the aggregated distribution patten, but the reasons of aggregation were different. The P.notabilis aggregated on 2-3-age trees was made by itself or by combined action between its own biological characteristics and environmental heterogeneity. The P.notabilis aggregated on 1-age trees was caused by some environmental factors such as temperature, humidity, light and so on