Enemy release, biotic resistance and the success of invasive forest insects

天敌释放、生物抗性和入侵森林昆虫的成功

• 批准号: RGPIN-2014-05123
• 负责人: Smith, Sandy
• 金额: $ 1.75万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=611455
• 关键词: Enemy; release; biotic; resistance; success

Globalization ensures that invasive species will continue to arrive, establish, and cause significant disruption in our ecosystems, leading to major global change. My research aims to increase our ability to manage such species through improved understanding of community interactions that affect the natural enemies regulating their populations. NSERC-DG funding will enable my research team to conduct the primary ecological studies proposed here, work that will elucidate key mechanisms driving these changes, as well as potential avenues for their mitigation in forests. Species interactions underpin the theories of enemy release and biotic resistance, and are a major thrust of my research. There is a great need to understand such processes in invaded forests, and my research program represents one of the few academic groups in Canada actively working in this area of invasive species and biological control. Recent introductions into Canada of several major forest insects (emerald ash borer (EAB), Asian long-horned beetle (ALHB), Sirex woodwasps) allow us to compare native and exotic natural enemy complexes, and to explore mechanisms by which these communities affect host mortality and pest invasion. I am best known for my contributions augmenting native natural enemies for biological control in forested systems, widely cited work still definitive in the field, however, my current research explores hypotheses around displacement of native species in order to better understand the invasion process. My specific interests are in community patterns of natural enemies following the introduction of exotics or through forest manipulation. Here, I investigate the enemy release and biotic resistance hypotheses as possible explanations for the community patterns observed as a new species establishes in the forest. I ask the question, which hypothesis better explains enemy attack and host productivity in two closely-related beetle systems; one indigenous (eastern pine engraver beetle, Ips pini), and one recently introduced from Europe (Tomicus piniperda). Both bark beetles are sympatric phloem-feeders attacking native and exotic pines across eastern Canada. Using this exotic-indigenous model system, I will test these two hypotheses with respect to levels of predation, parasitism, specialization, and community diversity of enemies and associates. I predict that in contrast to Europe, natural enemies of the indigenous North American beetle (Ips) will be both more diverse and specialized, and occur at greater densities than those on the nonindigenous beetle (Tomicus), and that this will lend support for the enemy release hypothesis. Biogeographic and ontongenic data will be derived across a gradient of beetle densities to quantify the degree to which enemies are present, and can account for beetle mortality and productivity. By comparing communities (natural enemies, mutualists, and competitors) and patterns associated with these beetles under manipulated densities and controlled biotic interactions, I will be able to establish the best explanatory mechanism. Results from this primary research will add to our understanding of invasion dynamics in our forests, and at the applied level, help to direct management strategies for alien insect species. They will be of interest to scientists, bio-control researchers, as well as policy-makers who regulate invasive species and the public and forest industry concerned with the ecological and economic effects of such species. My proposal requests funding to fuel not only basic knowledge underpinning processes of ecosystem resilience, but also to achieve unique and complementary HQP capacity in invasion biology for Canada’s most significant renewable resource, our forests.

全球化确保入侵物种将继续到达、形成并在我们的生态系统中造成重大破坏，导致重大的全球变化。我的研究旨在通过改善对群落相互作用的理解来提高我们管理这些物种的能力，这些群落相互作用影响着调节它们种群的天敌。NSERC-DG的资金将使我的研究团队能够进行这里建议的主要生态研究，阐明推动这些变化的关键机制，以及在森林中缓解这些变化的潜在途径。物种间的相互作用是敌人释放和生物抗性理论的基础，也是我研究的一个主要方向。非常有必要了解入侵森林中的这种过程，我的研究项目代表了加拿大为数不多的积极致力于入侵物种和生物防治领域的学术团体之一。 最近引入加拿大的几种主要森林昆虫(翡翠白蜡虫(EAB)、亚洲天牛(ALHB)、木蜂)使我们能够比较本地和外来的天敌复合体，并探索这些群落影响寄主死亡和有害生物入侵的机制。我最为人所知的是我为森林系统中的生物控制增加了本地天敌的贡献，这项被广泛引用的工作在该领域仍然是权威的，然而，我目前的研究探索了围绕本地物种迁移的假设，以更好地理解入侵过程。我特别感兴趣的是在引入外来物种或通过森林操纵后天敌的群落模式。在这里，我研究了敌人释放和生物抗性假说，作为对新物种在森林中建立时观察到的群落格局的可能解释。我提出的问题是，哪个假说更好地解释了两种密切相关的甲虫系统的敌人攻击和寄主生产力；一种是本土的(东部松材线虫，ips pini)，另一种是最近从欧洲引进的(Tomicus Piniperda)。这两种树皮甲虫都是共域韧皮部食性动物，攻击加拿大东部的本土和外来松树。 使用这个外来-本土模型系统，我将测试这两个假设，关于捕食水平，寄生性，专门化，以及敌人和同伙的社区多样性。我预测，与欧洲相比，北美本土甲虫(IPS)的天敌将更加多样化和专门化，并且比非本土甲虫(Tomicus)的发生密度更大，这将支持敌人释放假说。生物地理和致癌数据将通过甲虫密度的梯度得到，以量化敌人的存在程度，并可以解释甲虫的死亡率和生产力。通过比较这些甲虫在被操纵的密度和受控的生物相互作用下的群落(天敌、互助者和竞争者)和模式，我将能够建立最好的解释机制。 这项初步研究的结果将增加我们对森林入侵动态的了解，并在应用水平上帮助指导外来昆虫物种的管理策略。它们将引起科学家、生物控制研究人员以及管理入侵物种的政策制定者的兴趣，以及公众和林业行业对此类物种的生态和经济影响的关注。我的提案要求提供资金，不仅为支撑生态系统复原力进程的基本知识提供资金，而且还为加拿大最重要的可再生资源--我们的森林--实现入侵生物学方面独特和互补的HQP能力。