ROA: Comparative Plant-Herbivore-Enemy Interactions in a Monophyletic Group of Six Sawfly Species

这项研究的目的是通过从六个食草动物物种的取食类型的经验模式入手，发展对这种模式与物种与寄主植物和天敌关系的差异以及由此产生的种群动态的机械理解，从而推动生态学理论的发展。这种模式涉及到对植物资源的特异性梯度反应，从高度专一性的刺梢木蝇到更普遍的叶食性木蝇。除了诱导植物防御的相对重要性、食草动物的竞争、种群的稳定性、天敌的作用和三个营养水平的相互作用，以及叶蜂的分布和定殖能力外，还有14个假说涉及植物内变异、植物基因、计划强度、植物年龄和植物物种之间的特异性。方法以盆栽柳树为材料，采用田间观察和实验研究相结合的方法，对该物种的生活史特征、物种的分布和丰度、雌蜂产卵偏好与幼虫行为的关系、叶蜂及其寄生蜂的定殖能力和诱导植物防御作用等问题进行了研究。这项研究的目的是通过采用强有力的比较方法，对一个由6个种类组成的单系群进行知识推进，这些种类从种群动态稳定的物种到更容易爆发的物种。从机制上理解这些植物-食草动物-敌人相互作用的许多特征之间的联系可能会带来与此类系统相关的生态学理论的进步，并可能应用于农业和森林系统。

The objective of this research is to advance ecological theory by starting from an empirical pattern of feeding types among six sawfly herbivore species, and developing a mechanistic understanding of how the pattern relates to differences among species in their relationships with host plants, and natural enemies, and their resultant population dynamics. The pattern involves a gradient of specificity in response to plant resources from a highly specific shoot-galling sawfly to a more generalized leaf-feeding sawfly. Fourteen hypotheses address aspects of specificity in terms of within-plant variation, plant genotype, plan stree, plant age, and among plant species, in addition to the relative importance of induced plant defenses, herbivore competition, population stability, the role of natural enemies and three trophic-level interactions, and the distribution and colonization ability of the sawflies. Methods will employ field observations and experimental studies using potted willow plants to investigate questions on life history characteristics of the species, the distribution and abundance of species, the relationships between female preference in oviposition and consequent larval performance, the colonizing ability of sawflies and their parasitoids, and the role of induced plant defenses. This research is aimed at advancing knowledge by using a strongly comparative approach on a monophyletic group of six sawfly species which range from species with stable population dynamics to those that are more eruptive. The mechanistic understanding of linkage among many traits of these plant-herbivore-enemy interactions is likely to yield an advance in ecological theory relating to such systems, with probable application to agricultural and forest systems.