草原毛虫幼虫的食性及其空间格局

以禾草及嵩草在高寒草甸中的优势度为指标,研究草原毛虫(Gynaephora alpherakii)的食性、空间格局及其与植物群落的相关性.结果表明:草原毛虫的食性具有较强的选择性,其喜食程度排序为莎草科(Cyperaceae)＞禾本科(Gramineae)＞杂类草,特别对嵩草属(Kobresia Willd.)植物表现出强烈的偏好和倾向性;草原毛虫的分布型受制于其喜食植物的空间格局,在总体上呈聚集分布,但在小尺度下则常呈均匀分布;虫口密度依赖于喜食植物的丰富度和多样性,随着喜食植物的增加而显著上升,随着植物多样性的减少而显著下降;草原毛虫在高寒草甸生态系统中具有平衡物种关系、调控群落结构的功能;采用定向改变草地植物组成的农艺措施实现对草原毛虫数量的人工调控是实施虫害生态防治的有效途径.

Feeding Habit and Spatial Pattern of Gynaephora Alpherakii Larvae

By the index of dominance of grasses and Kobresia sp.in the alpine meadow,we analyzed the feeding habit and spatial pattern of Gynaephora alpheraki larvae and their relation to the properties of plant community.Results showed that: feeding habit of the caterpillars presented strong selectivity.The sequence of their feeding preference was: CyperaceaeGramineaeforbs.More particularly,they showed strong preference and tendency to feed on Kobresia sp..Caterpillar distribution was controlled by the spatial pattern of plants the larvae enjoyed feeding.Generally,caterpillars were in aggregative distribution,but in an even and small scale.The density depended on the richness of plants the larvae enjoyed feeding and on the plant diversity.The population rose significantly as their preferable plants increased,and declined significantly with plant diversity decreased.The caterpillar possessed function of counterpoising relationship among species and regulating the community structure in the alpine meadow ecosystem.It is effective to eradicate the insect pest by adopting agricultural measures to change the composition of grassland plants directionally so as to limit the number of caterpillars.