Suissa Study Has High Hopes For Plant-Ant Partnerships

May 24, 2024 by Logan Judy

by Randall Brown

Collaborations across research disciplines can lead to unexpected breakthroughs and discoveries. Collaborations across species lead to unexpected evolutionary paths of mutual benefit.

For example, some plants have managed to recruit ant bodyguards. They produce sugary nectar on their leaves that attracts the ants, then these very territorial and aggressive ant mercenaries patrol “their” plant and sting or bite herbivores that try to eat it.

These relationships are well-documented in flowering plants, but they also occur in non-flowering ferns. This is weird news for researchers, as it has long been thought that ferns lack the nectaries for such complex biotic interactions.

Jacob Suissa, assistant professor in the UT Department of Ecology and Evolutionary Biology, worked with colleagues at Cornell University, including fern expert Fay-Wei li and ant expert Corrie Moreau, to investigate how this phenomenon developed over the millennia. They recently published findings in Nature Communications about the evolutionary timeline and underlying factors of this interspecies partnership.

“The new elements of this work are twofold,” explained Suissa. “First, we discovered that nectaries—the structures that produce sugary nectar to attract ant bodyguards—evolved in ferns and flowering plants around the same time.”

This happened some 135 million years ago, coinciding with the rise of plant-ant associations in the Cretaceous period. 

“This timing is quite spectacular given that it is very late in fern evolutionary history, nearly 200 million years after their origin,” said Suissa. “But it’s very early in flowering plant evolutionary history, nearly at the start of their origin in the Cretaceous.”

The second new element is how it all happened. Ferns originally flourished as terrestrial plants, growing on the forest floor. They transitioned in a major way in the Cenozoic Era, around 60 million years ago, becoming epiphytic, or tree dwelling, plants.

They learned some new habits on their way up.

“We discovered that as ferns left the forest floor and moved into the canopies, either as epiphytes, climbers, or tree ferns, they tapped into the existing ant-flowering plant interactions and evolved nectaries,” said Suissa.

This presents a curious dynamic in the ecological and evolutionary history of these two plant lineages. Ferns and flowering plants diverged from a common ancestor more than 400 million years ago, but then hit their stride in parallel with their nectary evolution and the mutually beneficial ant-plant tradeoff.

“This suggests that there may be some ‘rules of life’ governing the evolution of non-floral nectaries and ant-plant mutualism,” said Suissa. “This work can help future investigations by providing the evolutionary framework or backdrop for ecological, developmental, or genomic analyses.”

Read Suissa’s full paper, “Convergent evolution of nectaries in ferns facilitated the independent recruitment of ant-bodyguard from flowering plants,” in Nature Communications.

Faculty Recognized for Excellence in Teaching, Service, and Academic Outreach

March 27, 2024 by Logan Judy

Faculty Recognized for Excellence in Teaching, Service, and Academic Outreach

During the 2023 UT College of Arts and Sciences faculty convocation, EEB faculty received awards for excellence in teaching, research, and academic outreach. 

Benjamin Keck, Lecturer – Excellence in Teaching Awards: Lecturer

Ben Keck is an outstanding and dedicated lecturer for the University of Tennessee who has supported student learning in the classroom, in the field, and in the lab for many years. His teaching practice stands out for his high level of innovation, enthusiasm, and positive course climate.

Keck is a dedicated undergraduate teacher of both introductory biology courses and upper-level majors courses. His appointment is across two units—general biology and EEB—and he makes a huge contribution both as a teacher and a mentor to students. As the Director of the Ichthyology Collection at UT, Keck also makes outstanding contributions to community outreach efforts to highlight the diversity and importance of fishes in Eastern Tennessee.

Randy Small, Professor – Excellence in Teaching Awards: Senior

Randy Small is a full professor in EEB and has been the director for Teaching and Learning in the Division of Biology since 2019. His first rate and long-standing contributions to the educational mission of the College of Arts and Sciences makes him the perfect winner of this award. Legions of students in EEB as a department and the whole Division of Biology have benefited from Small’s dedication to student success, outstanding teaching practice, and educational vision and leadership. This award is long overdue.

Laura Alexandra Russo, Assistant Professor – Faculty Academic Outreach Award: Research & Creative Activity

Russo is an outstanding faculty member in the Department of Ecology and Evolutionary Biology whose outreach has raised the profile of UT Knoxville scientifically and to the public. Her research engages the public, community groups, state agencies, students, and others to tackle declines in bee species and other pollinators and what can be done to reverse these trends. Her approach exemplifies engaged scholarship that is conducted with and in communities.

Russo regularly leads outreach events at state parks like Seven Islands and Roan Mountain and national parks like the Great Smoky Mountains, including pollinator and plant hikes and bioblitzes in which community members find, identify, and document biodiversity. She actively engages with UT Extension, giving seminars and running outreach events at UT’s research and education centers across the state.

Elisabeth Schussler, Professor – Outstanding Service Award

In her role as Director of Biology Teaching and Learning, Professor Schussler ensures our students in the lower-division biology courses receive excellence instruction from our graduate teaching assistants and nontenure-track faculty. 

She provides professional development opportunities for instructors to be at the top of their teaching game and it is this passion for high-quality teaching across the natural sciences that led her to build teams of faculty members across the college and university who also want high-quality instruction in lower-level courses. As Faculty Senate president, she supported the ideas of liberal arts learning through cultivation of a strong shared governance process.