Dissertation Research: Ant-Plants as Experimental Models in Ecology: An Example from Cordia Nodosa (Boraginaceae)

9423416对亚马孙秘鲁三个不同种群的皮尔斯普查表明，蚂蚁植物Cordia nodosa(紫草科)的生殖生物学与栖息在其上的蚂蚁物种之间存在显著的关联。当最常见的共生蚂蚁Allmer demerarae栖息时，Cordia nodosa很少开花和果实，但当三个较稀有的共生蚂蚁物种(Azteca spp.，Myrmelachista sp.)栖息时，结球科迪亚很少开花和结果。有趣的是，在营养生长的速度上没有明显的差异。这些结果表明，等位虫可能是节结拟线虫的一种寄生虫。此外，定殖性实验表明，寄生蜂对阿月浑子幼虫的捕食可能在一定程度上调节了多个蚂蚁物种在以节节拟小蜂为代表的单一资源上的共存。这些复杂的相互作用使节结线虫-蚂蚁组合成为一个理想的系统，在其中研究影响互惠关系进化的因素。这项研究将评估不同蚂蚁伙伴为植物提供的相对成本和收益，并将调查结节拟线虫的定植动态。这项研究将探讨群落生态学中的两个重要领域：寄生虫在互惠共生的进化和生态中所起的作用，以及天敌在维持物种多样性方面所起的作用。通过这样做，这项研究将加强对相互作用及其在生态群落中的作用的理解。

9423416 Pierce Censuses of three separate populations in Amazonian Peru show striking association between the reproductive biology of the ant-plant, Cordia nodosa (Boraginaceae), and the species of ant inhabiting it. Cordia nodosa rarely produces flowers and fruits when inhabited by the most common symbiotic ant species, Allomerus demerarae, but regularly flowers and fruits when inhabited by three, rarer symbiotic ant species (Azteca spp., Myrmelachista sp.). Interestingly, there is no detectable difference in the rate of vegetative growth. These results indicate that Allomerus may be a parasite of C. nodosa. Moreover, colonization experiments show that parasitoid wasp predation on Azteca foundresses may in part mediate the coexistence of multiple ant species on the single resource represented by C. nodosa. These complex interactions make the C. nodosa-ant assemblage an ideal system in which to investigate factors shaping the evolution of mutualisms. This research will assess the relative costs and benefits provided by different ant associates to the plant, and will investigate the dynamics of colonization by C. nodosa. This research will address two important areas in community ecology: the role that parasitisms have in the evolution and ecology of mutualisms and the role that natural enemies have in maintaining species diversity. In doing so, this research will enhance understanding of mutualistic interactions and their role in ecological communities.