RAPID: Eco-evolutionary dynamics of host-parasite interactions in a novel environment

从长远来看，控制入侵害虫的最佳方法是利用寄生性天敌在昆虫体内产卵。卵孵化并发育成幼虫，幼虫从内部取食昆虫宿主的身体。 因为这是一场生死斗争，自然选择强烈地作用于宿主以进化逃避寄生，并作用于拟寄生物以克服宿主的防御。当害虫入侵一个新的地区时，它们通常会留下适合攻击它们的寄生蜂。人们预计，在这种新的、没有敌人的环境中，进化可能会导致昆虫宿主的防御能力降低。 宿主对寄生虫的反应是重要的，因为宿主抗性影响生物控制程序。 在这些计划中，有意引入来自本地范围的敌人来控制入侵害虫。 当昆虫宿主再次暴露于其寄生物时，自然选择将再次做出反应。 本研究调查了斑点翅果蝇的防御水平如何在其入侵北美后发生变化，以及这些防御如何在从本地范围释放专业寄生虫后发生变化。 除了对生物控制的广泛影响外，该项目还有望对控制斑翅果蝇产生具体的见解，这是一种主要的农业害虫。入侵斑点翅果蝇的低电阻最初可能有助于生物控制，而增加或地理上可变的电阻水平可能会使生物控制不太成功或不太可预测regional.This项目调查生态进化动力学的主机-寄生蜂相互作用后，释放的经典生物控制剂，寄生蜂Ganaspis brasiliensis对入侵斑点翅果蝇（Drosophila suzukii）。与预期相反，在北美和欧洲的入侵范围内，斑翅果蝇的抵抗力似乎有所增加，而不是减少。这种增加的阻力可能源于减少竞争和丰富的资源，为斑点翅果蝇在异国情调的范围，允许维护高水平的防御化合物。在释放生物防治剂之前收集的初步数据表明，斑点翅果蝇对G。brasiliensis是相对高的，但它也是高度可变的，13-48%的寄生幼虫被宿主杀死。在这个项目中，G.巴西果蝇将在密歇根州的八个地点释放，这些地点已经有关于斑翅果蝇抗性水平的基线数据。 随后的调查将允许评估在释放共同进化的专业天敌后抵抗力的任何变化。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

Invasive insect pests are best controlled in the long term by parasitoid natural enemies that lay their eggs inside the insect. The eggs hatch and develop into larvae, which feed on the body of the insect host from the inside. Because this is a life-and-death struggle, natural selection acts strongly on the host to evolve to escape parasitism and on the parasitoid to overcome host defenses. When insect pests invade a new region, they usually leave behind the parasitoids that are adapted to attack them. It is expected that in this new, enemy-free environment, evolution could result in an insect host with lower defenses. Host evolution in response to parasites is important because host resistance impacts biological control programs. In these programs, enemies from native ranges are introduced intentionally to control invasive insect pests. When the insect host is once again exposed to its parasitoids, natural selection will once again respond. This study investigates how defense levels of the spotted wing drosophila have changed following its invasion of North America and how those defenses may change following the release of a specialist parasitoid from the native range. In addition to broad implications for biological control, the project promises to yield specific insights into control of spotted wing drosophila, which is a major agricultural pest. Lower resistance of invasive spotted wing drosophila could help biocontrol initially, while increased or geographically variable levels of resistance could render biocontrol less successful or less predictable regionally.This project investigates eco-evolutionary dynamics of host-parasitoid interactions following the release of a classical biocontrol agent, the parasitoid wasp Ganaspis brasiliensis against the invasive spotted wing drosophila (Drosophila suzukii). Contrary to expectations, the resistance of spotted wing drosophila seems to have increased instead of decreased in the invaded range in North America and Europe. This increased resistance may stem from reduced competition and ample resources for spotted wing drosophila in the exotic range, permitting maintenance of high levels of defensive compounds. Preliminary data collected prior to the release of the biocontrol agent show that spotted wing drosophila resistance to parasitism by G. brasiliensis is relatively high but also that it is highly variable with 13-48% of parasitoid larvae being killed by the host. In this project, G. brasiliensis will be released at eight sites in Michigan where there is already baseline data about resistance levels of spotted wing drosophila. Subsequent surveys will permit assessment of any changes in resistance following this release of a co-evolved specialist natural enemy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.