Bach Catherine E
Department of Biology, University of Michigan, 48109-1048, Ann Arbor, MI, USA.
Oecologia. 1991 Jul;87(2):233-239. doi: 10.1007/BF00325261.
This study investigated direct and indirect interactions between the ant, Pheidole megacephala (Fabr.), the green scale, Coccus viridis (Green), and the scale's host plant, Pluchea indica (L.). To examine the influence of ants on scales and host plants, scale population densities, scale mortality rates, and plant performance were studied on control host plants with ants and host plants from which ants had been removed. Plants with ants present had significantly greater scale population densities and scale reproductive rates than did plants without ants. Scale mortality from both parasitism and other causes was increased on plants without ants relative to plants with ants. Predator introduction experiments showed that P. megacephala removes predatory coccinellid larvae, even when they are covered with a protective coating. Host plants from which ants had been removed had significantly higher degrees of honeydew accumulation, which resulted in greater colonization by sooty mold and greater rates of leaf death and abscission. Ants also removed herbivorous lepidopteran larvae from plants. Results are discussed in terms of the potential of P. megacephala to exert direct and indirect positive effects on scale populations and an indirect positive effect on Pluchea indica.
本研究调查了大头蚁（Pheidole megacephala (Fabr.)）、绿绵蚧（Coccus viridis (Green)）及其寄主植物印度阔苞菊（Pluchea indica (L.)）之间的直接和间接相互作用。为了检验蚂蚁对蚧虫和寄主植物的影响，我们在有蚂蚁的对照寄主植物以及蚂蚁已被移除的寄主植物上，研究了蚧虫种群密度、蚧虫死亡率和植物表现。有蚂蚁存在的植物比没有蚂蚁的植物具有显著更高的蚧虫种群密度和蚧虫繁殖率。相对于有蚂蚁的植物，没有蚂蚁的植物上因寄生和其他原因导致的蚧虫死亡率增加。捕食者引入实验表明，即使捕食性瓢虫幼虫覆盖有保护涂层，大头蚁也会将其移除。蚂蚁已被移除的寄主植物上蜜露积累程度显著更高，这导致煤烟霉的定殖增加以及叶片死亡和脱落率更高。蚂蚁还会从植物上移除植食性鳞翅目幼虫。我们根据大头蚁对蚧虫种群产生直接和间接积极影响以及对印度阔苞菊产生间接积极影响的可能性来讨论研究结果。
