DISSERTATION RESEARCH: Phylogeny and Pollination Biology of Castilleae (Moraceae): Investigating the Evolutionary History of the Figs' Closest Relatives

The research of graduate student Wendy Clement, with the supervision of Dr George Weiblen at the University of Minnesota, compares figs (the genus Ficus) and Indian rubber (plants of the tribe Castilleae) of the mulberry family, Moraceae. These two very closely related plant groups differ greatly in species diversity, pollination biology, flower architecture, and geographical distribution. Comparative studies can better illuminate the course of evolution than studying one plant group in isolation. Much research has focused on the ecology and evolution of figs and their mutualistic pollinators, the fig wasps, because this relationship is a well-known example of coevolution among plants and insects. However, Castilleae are less well known, and further research on this group is needed before comparative work can be conducted. The goal of this study is twofold: (1) to determine how the species of Castilleae (ca 60 total) are related to one another and (2) to investigate the pollination biology of two putatively ancient Castilleae species. DNA sequence data and morphology are used to construct a phylogeny, a hypothesis of evolutionary relationships, for Castilleae. Phylogeny is used to trace the evolution of flower architecture and to estimate the age of the group. Age estimates and biogeographical data can reveal possible dispersal routes these plants may have followed from their center of origin to their present day locations. Pollination studies on the island of Papua New Guinea aim to identify the likely pollinator of an early diverging species of Castilleae, the poison tree (Antiaris toxicaria). Experiments and observations will examine the role of scent in attracting pollinating insects to the flowers of the poison tree and another ancient island endemic, Antiaropsis decipiens.

This research aims to elucidate evolutionary processes that have resulted in the patterns of plant diversity we see today. The investigation focuses on an important, yet understudied group of plants whose evolutionary history may shed light on the origin of tropical plant diversity. Fieldwork in Papua New Guinea contributes to science education in underdeveloped rural communities with limited contact and builds a network of international collaboration on rainforest ecology and evolution. Activities contribute to local conservation efforts in Papua New Guinea, while simultaneously building scientific capacity. Lastly, research on the evolutionary relationships of Castilleae provides an excellent opportunity to train University of Minnesota undergraduate students interested in evolution and phylogenetic systematics.