BRC-BIO: Understanding the Role of Species Interactions in Evolutionary Radiations Through the Evolution of Non-flying Mammal Pollination in the Iconic Plant Genus Protea

Interactions between plants and pollinators influence many ways in which flowers are shaped. Insects are the most common living pollinators, but many plants rely on other animals like birds and bats. In rare cases rodents or other non-flying mammals serve as pollinators to plants. The South African proteas, or sugarbushes, use many different pollinators, including non-flying mammals. Sugarbush species pollinated by rodents are different from sugarbush species pollinated by birds in important ways. They have different scents, different microbial associations, and different flower positioning. This project will sample sugarbushes in South Africa to determine the evolutionary relationships among species and to examine the traits and environmental circumstances that allowed non-flying mammal pollination to evolve. The work will engage undergraduate researchers in international field experiences and cross-cultural exchange of scientific ideas. Further, students will participate in cross-disciplinary sharing of ideas between biology and social work in a region that is rich in both plant and human diversity. Results from this project will provide a deeper understanding of how species interactions contribute to biodiversity and can help to predict how these complex systems may respond to undergoing global change. Little is known about the role of species interactions in contributing to evolutionary radiations. This project will help to understand the conditions that led to the evolution of non-flying mammal pollination in Protea and its role as a potential driver of diversification in this radiation. First, the work will increase the taxonomic breadth of sampled Protea species and enable the reconstruction of a more robust understanding of species relationships. Second, the improved understanding of species relationships will allow researchers to estimate how often pollination states changed over evolutionary time. Researchers will also reconstruct the ancestral pollination states of subclades and estimate the rate at which pollinator shifts have occurred. Finally, data on floral and whole-plant traits will be combined with environmental data to assess overall patterns of shifts to non-flying mammal pollination. This work will use a fascinating adaptation in an iconic radiation to understand the role of species interactions in generating diversity in one of the most biodiverse regions on Earth. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.