CAREER: COMMUNITY ASSEMBLY OF NECTAR-INHABITING MICROBES

在生态学中，当群落中发现的物种的组成受到物种殖民历史的影响时，即不同物种随时间加入的顺序和时间，就会发生“历史偶然性”。这个项目将使用一种独特的易于处理的研究系统来调查历史偶然性的原因和后果：加州蜂鸟授粉灌木的花朵中生长的花蜜真菌和细菌群落。这些微生物通过蜂鸟和其他传粉者迁移到花朵上，到达后利用花蜜作为繁殖的资源。研究人员将进行田间和实验室实验，以检验关于历史偶然性的四个假说：(1)更高的花密度下物种迁移史更具变异性；(2)更多可变的迁移史导致更多的物种组成变化，影响多个空间尺度上的物种多样性；(3)与资源消耗和毒素减少有关的物种特有特征解释了迁移史效应；以及(4)历史上诱导的微生物物种组成的变化通过改变花蜜的化学性质来改变花对植物繁殖的功能，从而改变传粉者对花的访问。这个项目将以两种方式整合研究和教育，使它们互惠互利。首先，以花蜜微生物为案例，开设一门新的探究式本科课程。在本课程中，学生将识别并解决未回答的研究问题，通过实践来学习科学过程。将采取一项适应性战略，每年实施一次课程，由科学教育专家进行课程评估，并在下一年纳入评估者的建议。这门课程将在另一个意义上具有适应性：每年新的研究结果将被用作学生建立假设的先验知识。第二，花蜜微生物系统将用于有针对性和广泛的外联活动。有针对性的活动将包括通过暑期实习指导来自代表性不足群体的高中生。广泛的活动将包括举办讲习班，与社区大学和高中的教师分享经验，发表同行评议的论文，传播通过本科课程和高中实习获得的科学教育知识。

In ecology, "historical contingency" happens when the composition of species found in a community is influenced by the history of species colonization; i.e., the order and timing in which different species joined over time. This project will investigate the causes and consequences of historical contingency, using a uniquely tractable study system: the communities of nectar-inhabiting fungi and bacteria that develop in the flowers of hummingbird-pollinated shrubs in California. These microorganisms immigrate to flowers via hummingbirds and other pollinators and, upon arrival, use nectar as the resource for reproduction. The researchers will conduct field and laboratory experiments to test four hypotheses about historical contingency: (1) species immigration history is more variable under higher flower density; (2) more variable immigration history results in more variable species composition, affecting species diversity at multiple spatial scales; (3) species-specific traits concerning resource consumption and toxin reduction explain immigration-history effects; and (4) historically induced changes in microbial species composition alters the function of flowers for plant reproduction by altering chemical properties of nectar and, consequently, pollinator visits to flowers.This project will integrate research and education in two ways that make them mutually beneficial. First, with nectar microorganisms used as a case study, a new inquiry-based undergraduate course will be taught. In this course, students will identify and work on unanswered research questions, to learn the scientific process by practicing it. An adaptive strategy will be taken, with an annual cycle of course implementation, course evaluation by science education experts, and incorporation of the evaluators' recommendations the following year. The course will be adaptive in one more sense: each year new research findings will be used as prior knowledge that students can build their hypotheses on. Second, the nectar microbial system will be used for targeted and broad outreach activities. Targeted activities will involve mentoring high-school students from under-represented groups through summer internships. Broad activities will involve running workshops to share experience with teachers from community colleges and high schools and publishing peer-reviewed papers to disseminate the knowledge on science education gained through the undergraduate course and the high-school internship.