摘要
重庆地区柑桔园束管食螨瓢虫(stethorus chengi)各虫态及种群在树冠上的分布以外层较多,内层较少,上层较多,中下层较少,在东南西北四个方位上无明显的差异。在树冠间各虫态及种群在主要发生期(5～10月)均以个体群的形成而成聚集分布。其聚集原因,在低密度时(约<3头/树)为外界因素引起,在高密度(<3头/树)时是外界因素和自身聚集行为共同作用的结果。抽样方式的比较表明单对角线、双对角线、棋盘式、平行跳跃、“Z”字形以及5点式抽样均可作为束管食螨瓢虫的抽样方法。其结果无显著差异。
Aggregation indices were used in a study of the spatial pattern ofStethorus chengi and its changes.It was found that these predators weredistributed mainly on the upper periphery of the citrus trees,whereas noheterogenity of their population density was observed on the south,north,west and east parts of the crown.They aggregated in groups in thecitrus orchard.The average size of the group varied with their meandensity in the field.External factors were responsible for their aggregationwhen the density was less than 3 beetles per tree while both externalfactors and the aggregation behavours of the predators were involved whenthe density was higher.A comparison of six traditionally used randomsampling methods showed that they could all be employed to investigatethe population density of S.chengi with no significant difference amongtheir sampling errors.
出处
《西南农业大学学报（自然科学版）》
CSCD
1991年第1期112-116,共5页
Journal of Southwest Agricultural University
基金
国家自然科学基金
西南农业大学青年科学基金资助
关键词
柑桔
食螨瓢虫
空间格局
果园
citrus
orchard
lady beetles
mite infestation
sampling methods
