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

本研究的目的是通过对六种锯蝇食草物种的取食类型的经验模式，以及对这种模式与物种之间与寄主植物、天敌的关系差异以及由此产生的种群动态之间的关系的机制理解，来推进生态学理论。这种模式涉及到对植物资源的特异性梯度，从高度特异性的刺梢锯蝇到更普遍的食叶锯蝇。除了诱导植物防御、草食动物竞争、种群稳定性、天敌的作用和三种营养水平的相互作用以及锯蝇的分布和定植能力的相对重要性之外，还有14个假设涉及植物内变异、植物基因型、株型、植物年龄和植物物种之间的特异性方面。方法采用野外观察和盆栽柳树实验研究相结合的方法，对该物种的生活史特征、物种分布和丰度、雌性产卵偏好与幼虫表现的关系、锯蝇及其拟寄生物的定殖能力等问题进行研究。以及诱导植物防御的作用。本研究的目的是通过对六种锯蝇的单系类群进行强烈的比较，从种群动态稳定的物种到那些更容易爆发的物种，从而提高知识。对这些植物-草食-天敌相互作用的许多性状之间联系的机制理解可能会在与这些系统相关的生态理论方面取得进展，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.