木槿上棉蚜及其捕食性天敌群落动态研究

对木槿上棉蚜及其捕食性天敌群落动态进行了研究。结果表明 :天敌群落主要由瓢虫类、食蚜蝇和蜘蛛类构成 ,物种丰富度较稳定 ,多样性呈先上升后下降趋势。瓢虫类主要分布于木槿中部和上部 ,食蚜蝇和蜘蛛类主要分布于木槿中部和下部。棉蚜的时间和空间生态位宽度均较大 ,表明棉蚜种群数量在时间维和空间维上的分布比较均匀。捕食性天敌中 ,龟纹瓢虫的时间×空间生态位宽度最大 ,表明其发生期较长、活动范围较广。与棉蚜的时间×空间生态位重叠度 ,龟纹瓢虫最大 ,其次为食蚜蝇 ,表明这 2种天敌对棉蚜的跟随作用较强。采用灰色关联分析法研究了各种捕食性天敌对棉蚜种群的影响程度 ,结果表明 :龟纹瓢虫 >异色瓢虫 >七星瓢虫 >食蚜蝇 >蜘蛛类

Study on Community Dynamics of Aphis Gossypii and Its Predatory Enemy Hibisus Syracuse Plants

An investigation was made in community dynamics of Aphis gossypii and its predatory enemy on Hibiscus Syracuse plants. The results showed that the predatory enemy community was composed of coccinellids, Syrphidae and araneids. The richness of the species was relatively stable and the diversity rose first and declined afterwards. Coccinellids were distributed mainly in the middle and upper parts of the plants and Syrphidae and araneids were distributed mainly in the middle and lower parts of the plants. Both temporal and spatial niche breadthes of Aphis gossypii were relative wide. These explained that the distribution of Aphis gossypii population was relatively even in the time sequence and in the different parts of rose mallow plants. Among the predatory enemies propylaea japonica had wider time×space niche breadth than other predatory enemies and this meant that it had longer period of occourrence and wider range of distribution. Propylaea japonica and Syrphidae had respectively the geatest and the second time×space niche overlap with Aphis gossypii . This results showed that the two predatory enemies had greater follow effect on Aphis gossypii rather than other predatory enemies. Grey relationl grade analysis on the influence of predatory enemies on population of Aphis gossypii showed that the influence was in order of Propylaea japonica> Harmonia axyridis> Coccinella septempunctata> Tromobididiidae> Araneids.