Dissertation Research: Intraspecific Competition for Mutualists: Conditional Interactions in a Membracid-Ant Association

虽然互利共生竞争的概念在过去一个世纪引起了相当大的关注，但很少有研究提供直接的实验证据来证明其发生。 这种缺失对于同翅目蚂蚁关联尤其明显。 拟议的研究旨在通过实验评估相邻同翅目聚集体在种内竞争蚂蚁互利共生服务的假设。 此前的操作实验已经证明，膜同翅目 Publilia Modeta（同翅目）在大多数年份都受益于蚂蚁 Formica oculta 的照料。 一系列实验将评估以下假设：（1）蚂蚁是膜菌的有限资源，（2）照料膜菌的蚂蚁数量，而不仅仅是蚂蚁的存在，对膜菌的适应性有显着影响，（3）寄主植物质量的种内和种间变异影响膜菌蜜露的化学成分，从而影响膜菌竞争蚂蚁的能力，以及（4）照料蚂蚁有益于膜菌通过减少掠食性蜘蛛（Pellenes sp.）的影响。 此类实验研究将为空间变化环境中互利相互作用的动态提供所需的见解。

While the concept of competition for mutualists has attracted considerable attention during the past century, few studies have provided direct experimental evidence documenting its occurrence. This absence is particularly evident for homopteran-ant associations. The proposed research is designed to experimentally evaluate the hypothesis that neighboring homopteran aggregations intraspecifically compete for the services of an ant mutualist. Manipulative experiments have previously demonstrated that the membracid Publilia modesta (Homoptera) benefits from being tended by the ant Formica occulta in most years. A series of experiments will evaluate the following hypotheses: (1) ants are a limited resource for membracids, (2) the number of ants tending membracids, and not just the presence of ants, has a significant impact on membracid fitness, (3) intra- and interspecific variation in host-plant quality influences the chemical composition of membracid honeydew and therefore the ability of membracids to compete for ants, and (4) tending ants benefit membracids by reducing the impact of predatory spiders (Pellenes sp.). Such experimental studies will provide needed insight into the dynamics of mutualistic interaction in spatially-variable environments.