DISSERTATION RESEARCH: Quantifying pollen limitation and reproductive assurance mechanisms in Gesnariae species with contrasting pollination systems

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Animal pollination is essential for seed set in many flowering plants. However, floral visitors do not always transfer enough pollen to fertilize all seeds. This phenomenon is known as pollen limitation and to avoid it, many plants have evolved mechanisms of autonomous self-pollination. This study will quantify pollen limitation and the contribution of autonomous selfing to the seed set of Gesnerieae species with contrasting pollination systems. The Gesnerieae is a plant group that diversified in the Greater Antilles. Some species are exclusively pollinated by hummingbirds or bats, while others are generalists (e.g. bats, hummingbirds and insects). Specialist flowers receive in average one visit per day, while generalist flowers receive many visits per day. Previous work suggests a relationship between pollen limitation and the presence of selfing mechanisms with hummingbird pollination. This project is designed to corroborate this finding using twelve Gesnerieae species from Dominican Republic and Puerto Rico. The research will illuminate our understanding of the processes underlying the evolution of pollination systems and selfing mechanisms in a poorly studied plant group from the Antillean islands. The development of selfing could be critical to the conservation of rare Gesnerieae species since it allows plants to reproduce in the absence of pollinators. Without the ability to self, plants could be a greater risk of extinction if pollinator populations decline. Thus, this study is of relevance to both our understanding of floral evolution and the conservation of rare and narrowly distributed plants in the fragile ecosystems of the Caribbean archipelago.