RUI: Natural-Enemy Response to Herbivore Host-Race Formation: Specialization to Host-Plant Complexes

亚伯拉罕森9710109在食草性昆虫的食物中加入一种新的宿主是一种常见的现象，这被认为是物种形成过程中重要的早期步骤。食草动物通过宿主-植物转变而形成物种的一个看似合理的结果是，食草动物的天敌可能也会相应地进行物种形成。研究人员将研究寄生黄蜂对其食草性猎物-黄杆球瘤诱导器(Eurosta Solidaginis)最近的宿主转移的生态反应。有证据表明，高大黄花(Solidago Altissima)是胆汁诱导剂的原始宿主，直到最近才将晚黄花(S.Gigantea)纳入胆汁诱导剂的饮食中。胆汁诱导剂目前以两种不同的“寄主相关小种”的形式存在，它们在遗传、行为和生理上都不同。这项研究的目的是确定胆汁诱导型捕食者内部和之间是否存在表型差异。特别是，研究人员询问，黄蜂种群是否在两个寄主小种的成虫产卵偏好方面存在差异，或者黄蜂捕食者在两个黄杆寄主小种上的幼虫表现是否不同。昆虫食草动物和它们的捕食者代表了绝大多数的生物多样性，具有相当大的经济意义。如上所述的寄主转移是常见的，已有农业、森林、濒危和其他本地植物种类的害虫的报告。当食草动物逃避捕食者时，农业害虫向新作物物种的转移可能会导致新作物物种的巨大经济损失。这项研究将增加对天敌向新寄主植物的相应转移的促进或限制，以及在利用新的寄主植物复合体时，什么可能影响捕食者提高效率的进化的理解。通过指导天敌对寄主取食植物的适应性研究，这项研究可能会改善对本地和引进害虫的生物防治。

ABRAHAMSON 9710109 The incorporation of a novel host into the diet of an herbivorous insect is a common occurrence, and it is thought to be a significant early step in the speciation process. One plausible consequence of herbivore speciation via a host-plant shift is that the herbivore's natural enemies might also undergo speciation in response. The investigators will examine the ecological response of the parasitic wasp, Eurytoma gigantea, to a recent host shift by its herbivorous prey, the goldenrod ball gall inducer (Eurosta solidaginis). Evidence suggests that tall goldenrod (Solidago altissima) was the original host of the gall inducer, and that only more recently was late goldenrod (S. gigantea) incorporated into the gall inducer's diet. The gall inducer currently exists as two distinct "host-associated races" that differ genetically, behaviorally, and physiologically. The objective of this study is to determine if phenotypic differences exist within and among the gall inducer predators. In particular the investigators ask if wasp populations differ in terms of adult oviposition preference for the two host races or if larval performance of the wasp predators differs on the two goldenrod host-races. Insect herbivores and their predators represent a great majority of biological diversity and are of considerable economic significance. Host shifts such as the one described above are common and have been reported for pests of agricultural, forest, endangered, and other native plant species. A shift by an agricultural pest to a new crop species may lead to high economic losses of the new crop species as the herbivore escapes its predators. This study will increase understanding of what may facilitate or limit a corresponding shift by natural enemies onto the novel host plant, and what may influence the evolution of increased efficiency of a predator in the utilization of the new host-plant complex. By directing research toward the adaptation of natural enemies to the plants on w hich their hosts feed, this research may improve the biological control of both native and introduced pests.