Dissertation Research: Evolutionary transitions: pollination biology and domestication of Artocarpus (Moraceae)

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The rapid diversification and rise to dominance of angiosperms is one of the enduring mysteries of evolutionary biology. While coevolution with animal pollinators is a major driver of angiosperm diversity, the degree of advantage conferred by animal pollination over wind pollination has been controversial, and the rarity of appropriate study systems has hampered progress in understanding the consequences of this transition. This research uses the tropical tree genus Artocarpus (Moraceae)- one of the rare systems exhibiting transitions from wind to animal pollination - to investigate evolutionary implications of that shift. Artocarpus pollination ranges from wind to a unique mutualism mediated by parasitic fungi that provide a brood site and nutrition for fly pollinators. This project provides the opportunity to understand morphological characters associated with pollination shifts, challenge assumptions about reversions from wind to animal pollination, and expose characters that may have been involved in the early radiation of flowering plants as they co-evolved with their animal pollinators. Artocarpus contains several underutilized crops including breadfruit, jackfruit, and terap. This research will support efforts to develop and improve important Artocarpus crops by increasing understanding of their reproductive biology. The project combines experimental pollinator-exclusion studies with morphological analysis to elucidate pollination mechanisms in Artocarpus and reveal morphological traits correlated with transitions between wind and insect pollination. These transitions will be combined with phylogenomic analyses for the group, to analyze changes in morphology in an evolutionary context, and to resolve the number and direction of wind-insect pollination transitions in Artocarpus. The research uses microsatellite DNA fingerprinting to uncover the domestication history of the insect-pollinated species Artocarpus odoratissimus, one of several underutilized tropical tree crops in this genus. Through collaborations in Malaysia, this project will promote scientific research on a group of underutilized crops in developing tropical regions and provide training in pollination biology to local scientists. The research will also provide research opportunities for undergraduates. The researchers will engage the public through displays at the Chicago Botanic Garden to promote awareness of pollination biology and tropical biodiversity.