山楂叶螨、苹果全爪螨及其捕食性天敌生态位研究Ⅲ──微气候生态位

STUDIES ON NICHES OF THTRANYCHUS VIENNENSIS, PANONYCHUS USMI AND THEIR PREDATORY ENEMIES(Ⅲ).MICROCLIMATIC NICHES

两种叶螨及其捕食性天敌的微气候生态位维的组成由苹果树冠内２０个位点的气温、照度和叶片含水一构成。研究表明：（１）温度、照度和叶片含水三者综合作用效应高于各单因子独立效应；三因子中温度与叶片含水量的联合作用效应高于其它因子间两两组合的效应。（２）两种叶螨及其天敌的生态位从６月到８月急剧缩小。叶螨间的生态位在６、７月趋于分离，而在８月份有较多的重叠。山楂叶螨的生态位与各天敌的重叠值较小或分离；苹果全爪螨的生态位在６月与小花蝽的重叠值较高，而在７月与草蛉及捕食螨的重叠值较高。小花蝽的生态位与草蛉、捕食螨的趋于分离；草蛉与捕食螨之间的生态位在７月份有较多的重叠，而在６月是分离的。（３）温度与叶片含水量组合是促成各种群微气候生态位转移的主因．

he microclimatic niches of the two leaf mites and their predatory enemies consist of il-luminance,temperature and leaf moisture content,which were taken from 20 little localitiesof the crown of apple tree. The results of multivariate statistical analysis show:(1)The threeecological factors affect the mites and their enemies integrally,in which the combination oftemperature and leaf moisture is more important than other combinations of the three eco-logical factors,(2)The niches of each species contract rapidly from June to August. The niches of the two mites overlap widely in August,less in June,but seperates in July.The niches of T. viennensis overlaps less or seperates with that of the predatory enemies,the niche of P. ulmi overlaps widely with that of Orius sauteri in June,and with that of Chrysopa sinica and Amblyseius pseudolongispinosus in July. The niche of O. sauteri tends to seperate with that of C.sinica and A. Pseudolongispinosus,the niche of C.sinica has a heavy overlap with that of A. pseudolongispinosus in July,but seperates between them in June. (3)Centres of the microclimatic niches of each species shift, which are mainly caused by the combination of temperature and leaf moisture content.