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

亚伯拉罕森9710109 将新宿主纳入草食性昆虫的饮食中是常见的，并且被认为是物种形成过程中重要的早期步骤。 草食动物物种形成通过寄主植物转移的一个可能的结果是，草食动物的天敌也可能经历物种形成的反应。 研究人员将研究寄生蜂Eurytoma lutea对最近由其食草性猎物，黄花球瘿诱导剂（Eurosta solidaginis）的宿主转移的生态反应。 有证据表明，高枝一枝黄花（Solidagoaltissima）是瘿诱导剂的原始宿主，晚一枝黄花（S.将其加入胆汁诱导剂的饮食中。 胆汁诱导剂目前作为两种不同的“宿主相关种族”存在，它们在遗传、行为和生理上不同。 本研究的目的是确定是否存在表型差异的瘿诱导捕食者内和之间。 特别是，调查人员问，如果黄蜂种群不同的成年产卵偏好的两个主机种族或如果幼虫的表现黄蜂捕食者不同的两个一枝黄花主机种族。 植食性昆虫及其捕食者代表了绝大多数生物多样性，具有相当大的经济意义。 诸如上述的宿主转移是常见的，并且已经报道了农业、森林、濒危和其他本地植物物种的害虫。 农业害虫向新作物物种的转移可能导致新作物物种的高经济损失，因为草食动物逃避了其捕食者。 这项研究将增加了解什么可能促进或限制相应的转变，由天敌到新的宿主植物，什么可能会影响进化的效率提高的捕食者在利用新的宿主植物复合体。 通过指导天敌对寄主植物的适应性研究，这项研究可能会改善对本地和外来害虫的生物防治。

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.