Collaborative Research: Does Escape From Natural Enemies Contribute to Invasiveness of Introduced Plants? A Test of the Evolution of Increased Competitive Ability Hypothesis

外来入侵植物目前是自然区域的主要威胁，因为它们可以通过社区传播并取代原生植被。 入侵物种被认为是仅次于栖息地丧失对本地多样性的影响，但机制，使植物成为入侵仍然知之甚少。 我们建议调查的机制，促进入侵一枝黄花，一种原产于北美和欧洲的入侵外来种。 我们计划测试的竞争能力增强（EICA）假说，认为由于专业的天敌可能不存在的范围内引进，外来植物可能会演变为投资较少的反草食动物防御，从而获得竞争优势超过本地植物的进化。 在一系列的实验中，我们将比较欧洲和美国的一枝黄花在其防御化学，其表现在存在和不存在食草动物，以及他们的能力，以支持增长的专家和通才昆虫。 EICA假说预测，欧洲的一枝黄花应该投资较少的次生化合物，因此应该支持更好的昆虫性能，并在没有食草动物的情况下具有生长优势。 如果耐受草食动物，或草食动物损害后恢复的能力，与最近的一些研究所建议的健身成本，那么欧洲的一枝黄花也将预计有减少的能力，以弥补损害相比，美国的一枝黄花。

Invasive, exotic plants are currently a major threat to natural areas because they can spread through communities and replace native vegetation. Invasive species are believed to be second only to habitat loss in terms of their impact on native diversity, but the mechanisms that allow plants to become invasive are still poorly understood. We propose to investigate the mechanisms promoting invasiveness in Solidago gigantea, a species native to North America and an invasive exotic in Europe. We plan to test the Evolution of Increased Competitive Ability (EICA) hypothesis, which holds that because specialized natural enemies may be absent from the introduced range, exotic plants may evolve to invest less in anti-herbivore defenses and thereby gain a competitive advantage over native plants. In a series of experiments, we will compare European and US goldenrods in terms of their defensive chemistry, their performance in the presence and absence of herbivores, and their ability to support growth of both a specialist and a generalist insect. The EICA hypothesis predicts that European goldenrods should invest less in secondary compounds, and therefore should support better insect performance and have a growth advantage in the absence of herbivores. If tolerance to herbivory, or the ability to recover following herbivore damage, has associated fitness costs as suggested by some recent studies, then European goldenrods would also be expected to have reduced abilities to compensate for damage, compared to US goldenrods.