DISSERTATION RESEARCH: Systematics and Pollinator Transitions in the Species-Rich Genus Ruellia (Acanthaceae)

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The co-evolution of plants and their pollinators has given rise to a variety of flower shapes, colors, and sizes. Certain flower traits are frequently correlated, and these correlations define what is commonly termed a "pollination syndrome". For example, white flowers that open at night and have long tubes are generally indicative of hawkmoth pollination. Transitions in pollination syndromes are widely believed to contribute to plant speciation, including the origin and radiation of the flowering plants. The goal of this research is to study such transitions by focusing on the species-rich genus Ruellia. With approximately 300 species, Ruellia is the second largest genus in the tropical family Acanthaceae (ca. 4,000 species). Based on preliminary evolutionary analyses (E. Tripp, unpub. data), closely related species often display a variety of pollination syndromes, indicating that pollinators have likely had a large role in the overall speciation of Ruellia. Though Mexico is a hotspot for Ruellia diversity, current taxonomic sampling and field collections of Mexican Ruellia species is poor. This proposal describes how a plant collecting expedition through southern portions of Mexico, coupled with museum-based work out of national and international herbaria, will permit a full exploration of species relationships and the evolution of pollination syndromes in Ruellia. Methods include molecular sequencing, standard genealogical analyses, plant identification and morphological analyses, field collections and herbarium curation, and the construction of local and/or regional floristic treatments.Because pollination transitions contribute to plant diversification, studying such transitions as well as relationships among Ruellia species can lend insight into processes involved in plant speciation, and thus to the generation of biodiversity. Knowledge of biodiversity is of paramount importance to everyone, particularly knowledge of tropical taxa where critical habitat is disappearing at unprecedented rates. Further, botanical collections have been fundamental to all biological investigations and remain essential today, especially in tropical regions where much diversity has yet to be documented. It has been shown that collections data can be useful in conservation decision-making1,2. This work will benefit the conservation infrastructure in Mexico and promote international scientific collaboration between US and Mexican institutions, botanists, and students. To ensure our success in understanding the history and future of biodiversity, it is imperative that the upcoming generation of biologists continue to be trained in traditional field biology and museum/herbarium curation, as well as modern molecular methods.