Collaborative Research: Discovering eukaryotic symbionts across diverse insect communities

尽管生物多样性在全球范围内下降，但许多物种仍未被发现。“隐藏的”多样性的一个主要来源可能是生活在昆虫体内的许多蠕虫、线虫、真菌和原生共生体。众所周知，这类生物与昆虫有关，但检测它们的存在并量化它们的多样性构成了重大挑战。这可能是对全球物种多样性理解的一个巨大疏忽：如果与昆虫相关的共生体通常也专门针对一种或几种昆虫，这将意味着存在数百万未描述和未统计的物种，需要修订全球物种丰富度估计。这项研究将导致开发新的方法来揭示生活在昆虫体内的真核共生体。它还将把这些方法应用于迄今为止最雄心勃勃的昆虫-共生体多样性调查，跨越两个不同栖息地的两个自然昆虫群落。这项研究将被整合到爱荷华州和俄亥俄州的公共活动中，参与者将了解生物多样性，并参与对研究中使用的昆虫进行采样。一个主要的主题将是，即使在我们自己的后院，也可能隐藏着多少多样性。该项目还将有助于在两个校区培训本科生和研究生，其中一个校区主要是为本科生服务的机构。学生将参与拟议的研究，但也将在教学和科学考察中获得宝贵的指导。研究人员将开发聚合酶链式反应阻断引物，抑制来自五大目昆虫(占所有已描述昆虫物种的75%)的18S rRNA的扩增，但允许从样本中的任何其他真核生物扩增18S rRNA。他们还将反复为在自然样品中检测到的大的和/或常见的共生体群体设计阻断引物，以便也可以检测到较小/稀有的共生体。这些方法将能够检测到与五个最大目(鞘翅目、膜翅目、双翅目、半翅目和鳞翅目)的昆虫有关的任何真核共生体。两项首次的共生生物多样性调查将把开发的方法应用于从两个自然群落中分别收集的1000种昆虫，询问所有昆虫宿主是否有真核共生生物。初步数据显示，阻滞剂有效地大大减少了寄主昆虫的DNA扩增，并成功地检测到了与个别昆虫有关的蠕虫、线虫、真菌，甚至单细胞顶端复合体原生生物。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Even as biodiversity declines worldwide, many species remain undiscovered. One major source of “hidden” diversity may be the many mites, nematodes, fungi, and protist symbionts that live inside insects. Such organisms are known to have associations with insects but detecting their presence and quantifying their diversity pose major challenges. This is a potentially massive oversight toward an understanding of global species diversity: if insect-associated symbionts are also often specialized on just one or a few species of insect, this would imply the existence of millions of undescribed and uncounted species, requiring a revision of global species richness estimates. This research will lead to the development of new methods to reveal the eukaryotic symbionts living inside insects. It will also apply those methods to the most ambitious surveys of insect-symbiont diversity to date, spanning two natural insect communities in two different habitats. The research will be integrated into public events in Iowa and Ohio where participants will learn about biodiversity and participate in sampling insects to be used in the research. A major theme will be how much diversity may be hiding even in our own backyards. This project will also contribute to the training of undergraduate and graduate students on two campuses, one which is a primarily undergraduate-serving institution. Students will participate in the proposed research but will also receive valuable mentoring in teaching and scientific outreach.The researchers will develop PCR blocking primers that inhibit amplification of 18S rRNA from the five largest orders of insects (representing 75% of all described insect species) but that permit amplification of 18S rRNA from any other eukaryote in a sample. They will also iteratively design blocking primers for large and/or common symbiont groups detected in natural samples so that smaller/rare symbionts may also be detected. These methods will allow detection of any eukaryotic symbiont associated with insects in the five largest orders (Coleoptera, Hymenoptera, Diptera, Hemiptera, and Lepidoptera). Two first-of-their-kind symbiont diversity surveys will apply the developed methods to 1000 insects collected from each of two natural communities, interrogating all insect hosts for eukaryotic symbionts. Preliminary data show that blockers are effective at greatly reducing host insect DNA amplification and successfully detect mites, nematodes, fungi, and even single-celled apicomplexan protists associated with individual insects.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.