BRC-BIO: Evolution and ecology across the mutualism-parasitism transition in leafflower plants (Phyllanthaceae) and leafflower moths (Lepidoptera: Gracillariidae: Epicephala)

Relationships among species in nature may vary from mutually beneficial (mutualism) to those in which individuals from one species benefits and individuals from the other species are harmed (antagonism, including parasitism). Transitions between mutualism and parasitism have evolved often. However, little is known about the biology of organisms that have undergone these transitions.

Understanding this important evolutionary transition has important ramifications for medicine, agriculture, and epidemiology. This project supports research by four master’s students studying the biology of one group of insects (leafflower moths) that have evolved from mutualistic to parasitic relationships with their host plants. Student projects will study the genetics of these moths in Texas and the southeastern United States.

They will also explore the diversity of bacteria associated with these moths’ caterpillars, and the biology of moths in this genus that were just discovered in Puerto Rico. Students will also train with external collaborators, and travel to a scientific conference to present their findings. The University of Texas Permian Basin (UTPB) is a Hispanic-Serving Institution and the largest university in the Permian Basin of West Texas, with a student population that is majority-first generation college students.

This project will also fund summer research experiences for five undergraduates (four from UTPB, one from the University of Puerto Rico, Río Piedras Campus), and for a group of UTPB undergraduates to attend a national scientific meeting in summer 2023.

Transitions between mutualism and parasitism have occurred frequently throughout the Tree of Life. This proposal outlines research on the evolution and ecology of a brood pollination mutualism between leafflower plants in the family Phyllanthaceae and leafflower moths in the genus Epicephala. Interestingly, this mutualism has repeatedly broken down into parasitism.

This research will gather the first data on the ways in which these parasites’ population structure evolves in response to their host diversity. It will also study the macroevolution of mutualism gain and loss in an unstudied tropical North American radiation of these plants and insects. Finally, the work will provide data on the way in which third party associates (larval microbiomes) vary with the mutualism-parasitism transition and shifts among host plant lineages.

Results from this research will be readily interpreted in the context of previous work on the biology of the mutualistic congeners of these parasites in Asia and the Pacific. In doing so, this proposal will generate new data for future work on this system and develop this emerging model system in evolutionary ecology.

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.