CAREER: COMMUNITY ASSEMBLY OF NECTAR-INHABITING MICROBES

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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.