Systematics of Maxillariinae(ORCHIDACEAE): Generic Delimitation, Pollinator Rewards, and Pollination

University Of Florida, Gainesville FL

Investigators

Abstract

0234064 Williams and Whitten The purpose of this project is to collect, study, and classify the species of Maxillaria, one of the largest and most poorly known orchid genera. New species of Maxillaria are discovered frequently in the tropics, and the total number of currently described species exceeds 650. Orchids are one of the showiest and most species-rich families of plants, yet are very poorly studied. As tropical forests are destroyed at an increasing rate, the most basic questions we need to answer are 1) How many species exist? 2) Where do they grow? 3) How are they related to each other and to other plants? Maxillaria species are often large, conspicuous, and numerically important components of the epiphytic vegetation in the Neotropics, but species are difficult to identify. The classification of Maxillaria and its relatives has been chaotic for more than a century, and current taxonomic treatments offer little hope of stability unless the revisions are based on modern DNA- and morphology-based phylogenies (hypotheses of evolution). In this project, researchers at the University of Florida will coordinate studies of Maxillaria with collaborators in Mexico and Central and South America. DNA sequencing of nuclear and plastid genes will be used to acquire new data in order to classify and to estimate phylogenetic relationships within this large genus. Specimen images, identification keys, publications, and on-line databases will be produced to help botanists and the public identify these orchids. The pollinators of Maxillaria flowers and the type and composition of the floral rewards (nectar, oil, resin, etc.) will also be studied. By plotting these pollination data onto evolutionary "trees", one can gain insight into how pollinators have influenced speciation and diversity within this genus and in other plants. This project will provide basic information on the biodiversity of a major group of tropical plants. This information is fundamental to broader biodiversity studies such as regional inventories (floras), choosing areas of high diversity for conservation priorities, and documenting rates of species extinction. Specimens, photographs, and DNA samples will be archived and will serve as a record of orchid species that may become extinct within the near future. This grant will train PhD level students in modern plant systematics. Because orchids are beautiful and charismatic "poster child" plants, information on their diversity and biology can be used to raise public awareness and support for conserving tropical ecosystems. Women graduate students from Brazil and Ecuador and male students from Mexico and Costa Rica will broaden the representation of scientists from Central and South America and bring gender, ethnic and geographical diversity to this collaborative project. Collaboration with Mexican, Ecuadorian, and Brazilian scientists will enhance the network of partnerships which have been developed with other groups.