Claire Hemingway in ‘The Conversation’: Bees have irrational biases when choosing which flowers to feed on − just like human shoppers do
Bees have irrational biases when choosing which flowers to feed on − just like human shoppers do
Just like people confronted with a sea of options at the grocery store, bees foraging in meadows encounter many different flowers at once. They must decide which ones to visit for food, but it isn’t always a straightforward choice.
Flowers offer two types of food: nectar and pollen, which can vary in important ways. Nectar, for instance, can fluctuate in concentration, volume, refill rate and accessibility. It also contains secondary metabolites, such as caffeine and nicotine, which can be either disagreeable or appealing, depending on how much is present. Similarly, pollen contains proteins and lipids, which affect nutritional quality.
When confronted with these choices, you’d think bees would always pick the flowers with the most accessible, highest-quality nectar and pollen. But they don’t. Instead, just like human grocery shoppers, their decisions about which flowers to visit depend on their recent experience with similar flowers and what other flowers are available.
I find these behaviors fascinating. My research looks at how animals make daily choices – especially when looking for food. It turns out that bees and other pollinators make the same kinds of irrational “shopping” decisions humans make.
Predictably irrational
Humans are sometimes illogical. For instance, someone who wins $5 on a scratch ticket immediately after winning $1 on one will be thrilled – whereas that same person winning $5 on a ticket might be disappointed if they’re coming off a $10 win. Even though the outcome is the same, perception changes depending on what came before.
Perceptions are also at play when people assess product labels. For instance, a person may expect an expensive bottle of wine with a fancy French label to be better than a cheap, generic-looking one. But if there’s a mismatch between how good something is and how good someone expects it to be, they may feel disproportionately disappointed or delighted.
Humans are also very sensitive to the context of their choice. For example, people are more likely to pay a higher price for a television when a smaller, more expensive one is also available.
These irrational behaviors are so predictable, companies have devised clever ways to exploit these tendencies when pricing and packaging goods, creating commercials, stocking shelves, and designing websites and apps. Even outside of a consumer setting, these behaviors are so common that they influence how politicians design public policy and attempt to influence voting behavior.
Like minds
Research shows bumblebees and humans share many of these behaviors. A 2005 study found bees evaluate the quality of nectar relative to their most recent feeding experience: Bees trained to visit a feeder with medium-quality nectar accepted it readily, whereas bees trained to visit a feeder with high-quality nectar often rejected medium-quality nectar.
My team and I wanted to explore whether floral traits such as scents, colors and patterns might serve as product labels for bees. In the lab, we trained groups of bees to associate certain artificial flower colors with high-quality “nectar” – actually a sugar solution we could manipulate.
For example, we trained one group to associate blue flowers with high-quality nectar. We then offered that group medium-quality nectar in either blue or yellow flowers.
We found the bees were more willing to accept the medium-quality nectar from yellow flowers than they were from blue. Their expectations mattered.
In another recent experiment, we gave bumblebees a choice between two equally attractive flowers – one high in sugar concentration but slower to refill and one quick to refill but containing less sugar. We measured their preference between the two, which was similar.
We then expanded the choice by including a third flower that was even lower in sugar concentration or even slower to refill. We found that the presence of the new low-reward flower made the intermediate one appear relatively better.
These results are intriguing and suggest, for both bees and other animals, available choices may guide foraging decisions.
Potential uses
Understanding these behaviors in bumblebees and other pollinators may have important consequences for people. Honeybees and bumblebees are used commercially to support billions of dollars of crop production annually.
If bees visit certain flowers more in the presence of other flowers, farmers could use this tendency strategically. Just as stores stock shelves to present unattractive options alongside attractive ones, farmers could plant certain flower species in or near crop plants to increase visitation to the target crops.
Claire Therese Hemingway, Assistant Professor of Ecology & Evolutionary Biology, University of Tennessee
This article is republished from The Conversation under a Creative Commons license. Read the original article.
NSF CAREER Award Expands Ecological Research for Kivlin Lab
NSF CAREER Award Expands Ecological Research for Kivlin Lab
Associate Professor Stephanie Kivlin earned a 2024 National Science Foundation (NSF) CAREER Award for her project proposal “Spatiotemporal Dynamics of Plant-Mycorrhizal Fungal Symbioses at Continental Scale.” The work will help build a greater understanding of ways that plant life reacts to changes in global conditions.
The Kivlin Lab, within the UT Department of Ecology and Evolutionary Biology (EEB), researches the drivers of distributions of mycorrhizal fungi—fungi that have symbiotic relationships with the roots of many plants—and how global change may affect them and their interactions with these plants. The CAREER project will expand the lab team’s focus to study foundational trees of North America.
“This CAREER award is pivotal to provide support to map the current and future distribution of plants and mycorrhizal fungi and the outcome of symbiosis throughout the continental US for the first time,” said Kivlin.
Global change is forcing organisms to shift their biogeographical ranges and change their seasonal activities—affecting their growth, survival, and reproduction. Microbial symbionts can modulate the response of host organisms to global change, but it isn’t known how interactions among hosts and these symbionts shift as conditions change planetwide.
Researchers will collect fungi from the roots of 10 foundational tree species across the Eastern US for four years and sequence long-term herbarium samples to understand historical fungal communities. They will address how these trees and their mycorrhizal fungal symbionts may become decoupled over space and time as plants and fungi shift ranges.
“We will leverage the USFS Forest Inventory and Analysis database, which involves more than 14,000 locations, to understand how mycorrhizal fungal distributions have shifted since 2001,” said Kivlin. “We will then assess how plants grow, survive, and reproduce with home fungi versus those that are moved to simulate range shifts under global change.”
For students, the grant will enable the development of two Course-based Undergraduate Research Experiences (CUREs) focused on this research.
“This research and outreach is collaborative with the Easy as Play initiative, led by EEB Professor Liz Derryberry, through which we will engage dozens of middle school students in plant-mycorrhizal fungal research and training,” said Kivlin.
CAREER award funding will also support graduate student Ella Segal in the Kivlin lab, plus a postdoctoral researcher and a technician.
“Graduate students from EEB will also be engaged in CUREs,” said Kivlin. “They will gain valuable pedagogical knowledge in experiential learning, which will prepare them for the workforce upon graduation.”
By Randall Brown
UT Faculty, Students Sharing Ecology Research
UT Faculty, Students Sharing Ecology Research
Ecologists from around the world learned about research conducted at the University of Tennessee, Knoxville, during the annual Ecological Society of America meeting this month.
About 20 oral presentations plus poster sessions featured UT faculty and students’ findings in areas including climate change, biodiversity, ecosystems, symbiotic relationships, and species that range from Appalachia to Africa. The ESA meeting in Long Beach, California, Aug. 4-9, drew around 3,000 attendees.
The UT presenters include half a dozen faculty members from the Department of Ecology and Evolutionary Biology (EEB): Distinguished Service Professor Paul Armsworth; Research Professor Richard Norby; Associate Professors Orou Gaoue, Xingli Giam, and Stephanie Kivlin; Lecturer Amanda Benoit; and Adjunct Lecturer Joseph Edwards.
“The ESA annual meeting is an outstanding opportunity for ecologists to learn about new work, network, and meet up with collaborators and colleagues, and is always so inspiring,” said Professor Jen Schweitzer, head of the EEB department. “Everyone attending always returns with new ideas and so much excitement about their research and next directions. ESA also does a great job of providing diverse professional development opportunities to help attendees expand their toolboxes of professional and discipline-based skills. I am thrilled there was such great attendance this year!”
The UT Institute of Agriculture had two faculty members present their research, Professor Jennifer DeBruyn and Assistant Professor Mark Wilber, and affiliates of the National Institute for Modeling Biological Systems (NIMBioS) also were delivering talks at ESA’s meeting.
Two EEB researchers received awards from ESA this year. PhD student Alivia Nytko was honored for her 2023 ESA poster presentation on research that suggests plant rarity might be an evolutionary adaptation. EEB Professor Michael Blum, associate dean for research and creative activity in the College of Arts and Sciences, received recognition for an outstanding ecological research paper, which focused on rapid plant evolution in how ecosystems respond to global change.
By Amy Beth Miller
Simberloff Receives Honorary Doctorate
Simberloff Receives Honorary Doctorate
by Amy Beth Miller
Daniel Simberloff’s contributions to ecology and conservation biology as a researcher, educator, and mentor received recognition this spring from Tel Aviv University (TAU).
Simberloff, the Gore Hunger Professor of Environmental Studies in the University of Tennessee, Knoxville’s Department of Ecology and Evolutionary Biology, received an honorary doctorate during a May 30 ceremony at TAU. The certificate cites Simberloff’s “legendary achievements as an ecologist, conservation biologist and invasive species expert.”
Simberloff is the first ecologist to receive an honorary degree from Tel Aviv University, and the university also asked him to open a symposium that week that brought together scientists from across Israel studying biological invasions and government policymakers.
Simberloff first served as a visiting professor at Tel Aviv University in 1996 and before that had co-advised a TAU doctoral student, with whom he continued to collaborate. He also was involved in planning for the university’s Steinhardt Museum of Natural History.
The honorary degree presented to Simberloff notes that his work “is studied by virtually every undergraduate student in the field worldwide” and is “helping to prevent extinctions and protect biodiversity.”
“It’s really gratifying,” he said of the honor, “because it’s a nation with a lot of ecologists doing world-class work and publishing in all the leading journals, and people working right in my major area of biological invasions and much concerned with conservation in a very challenging environment.”
The honorary degrees were presented during the annual meeting of TAU’s Board of Governors, which includes representatives from around the world.
The eight other honorees included the co-founder of WhatsApp and the first Jewish woman appointed to the Supreme Court of Canada, as well as others recognized for academics, contributions to the arts, activism, and entrepreneurship.
During the ceremony, TAU President Ariel Porat said, “Even in wartime, we must maintain our way of life. Especially for a university, it is crucial to continue researching, teaching, and contributing to society. Today’s honorary degrees ceremony shows that the pursuit of science and knowledge never stops.”
Simberloff’s contributions to understanding the natural world also were recognized in August 2023 by the British Ecological Society (BES). The honorary membership he received in the BES is the highest honor it bestows, recognizing exceptional contribution at the international level to the generation, communication, and promotion of ecological knowledge and solutions.
McGill University awarded Simberloff an honorary Doctor of Science degree in June 2023, calling him a pioneer and renowned scholar in ecology and conservation biology. “Studying the susceptibility of ecosystems to biological invasions years before the phenomenon became a thriving subdiscipline, Simberloff is a world leader in this research area,” McGill said in honoring him.
Remembering Our Friends
Remembering Our Friends
During the past few years, the Department of Ecology and Evolutionary Biology has lost many members of our community. Here we recognize some of the staff and students who came through our program—including the zoology and botany programs before they became EEB—and the faculty who dedicated their professional careers to creating knowledge in their research fields and sharing that knowledge with students and others. We are grateful to have known these wonderful people and for all of their time and commitment to EEB.
David A. Etnier said, “The sleeping dog fears not the chicken.” Luckily, most of Etnier’s (Ets’) lessons for his dozens of graduate students were clearer than this quote that still leaves most of us scratching our heads. Ets started at UT in 1965 and for more than 40 years he and his students were largely responsible for bringing the number of described freshwater fishes in Tennessee from about 70 to over 350; playing a large role in the first test of the Endangered Species Act with the snail darter US Supreme Court case; publishing “The Book” as The Fishes of Tennessee is known to most Tennessee ichthyologists; describing a plethora of other aquatic organisms; and starting many conservation efforts for non-game fishes. There are innumerable stories to be shared about Ets, but one take away for many of us was how to be compassionate for and in awe of the natural world and people around us. Though Ets passed away on May 17, 2023, his storied legacy is surely indelible.
Ed Clebsch came to UT as a faculty member in botany in 1963. He was a driving force in plant ecology at UT as one of the early researchers making connections between plant physiology and population/community ecology. Ed published classic papers on photosynthesis and published on diverse topics including the impact of wild pigs, the demography of forest gaps, and the distribution of radioactive materials from fallout in the Smokies. After retiring from UT, he fostered efforts to encourage the use of Tennessee native plants in gardens and continued his long involvement with the Spring Wildflower Pilgrimage.
Ray Holton was a faculty member in the Department of Botany and head from 1965-1985, retiring in 1996. Ray was a plant physiologist and phycologist interested in the freshwater red algae Boldia, which is found in streams in the eastern US, including the Southern Appalachians. Ray documented its distribution and worked to understand the physiological adaptation to fresh water. After retirement, Ray volunteered in the UT Herbarium, and he and his wife established the Ray and Linda Holton Endowment in EEB, which generously funds undergraduate research.
Jerry Olson was a long-time researcher in the Environmental Sciences Division of Oak Ridge National Lab and was one of the founders of the former graduate program in ecology. He was a pioneer in the study of succession on sand dunes, ecosystem ecology, and mathematical modeling, including the use of stable isotopes to understand plant physiological processes and carbon cycling. He retired from ORNL in 1985 but remained active in fostering research on dune systems and was a strong supporter of Tennessee Citizens for Wilderness Planning, along with many cultural organizations.
David K. Smith is remembered as a passionate instructor and avid field botanist. During his more than 30 years at UT, he taught diverse undergraduate courses, including Plant Morphology, Field Botany, and Bryology. He traveled the world, from the southern Appalachians to Alaska and China, collecting bryophyte specimens to increase our knowledge of plant biodiversity. We greatly appreciate the thoughtful donation of his bryology books to the UT Herbarium (TENN) by his wife, Mary Smith.
Gerald L. (Jerry) Vaughan, professor emeritus, was one of EEB’s inaugural faculty members. He was a physiologist known for his early work on photobiology and animal pigments and, later in his career, on the impacts of surface mining and water chemistry on communities of aquatic animals. He was an accomplished metal sculptor, a maker of fine gemstone jewelry, a talented musician, and a raconteur who enriched the lives of all who knew him.
We also recognize these former EEB community members: Clif Amundsen, Bruce Bauer, Frank Bowers, Zeno Brown Jr., Sarah Cait, Danny Cobb, Edward Darden, John Delozier, Scott Duke-Sylvester, Barbara Gudmundson, Walter Heck, John (Bobby) Mullins, Paul Redlearn, Richard Robinson, Edward Smythe, Barnard Vaughn, and Harry Wood. Our heartfelt condolences to their families and friends for their loss.
Greenhouses Grow More Than Plants
Greenhouses Grow More Than Plants
Perhaps best known for showcasing Rotty Top—the huge, stinky, corpse flower that bloomed a few summers ago—the Department of Ecology and Evolutionary Biology Greenhouse is a remarkable asset and gem on the University of Tennessee’s Knoxville campus. It consistently supports departmental research as well as an array of classes across campus—from biology and plant sciences to landscape architecture and art.
More than 12 EEB faculty, 25 graduate students, 50 undergraduate students, and other volunteers use the greenhouses every year to grow a variety of plant species for research. Additionally, 650 students and 12 different classes annually visited the greenhouses from 2022-2024 to explore the plant collections, conduct class experiments, and gain a better understanding of the functionality of greenhouses through part-time jobs and internships.
Under the management of Director Jeff Martin and Co-director Kaitlyn Palla, the greenhouses also serve many other outreach and service functions to UT and beyond. For example, greenhouse staff maintain outdoor gardens located around the Hill, including a fern garden on the east side of Hesler Biology Building, a moss garden in the courtyard of the Science and Engineering Research Facility (SERF), and a native plant garden in the courtyard behind Dabney Hall. These gardens serve as important green spaces for students, faculty, and staff to learn about plants and to de-stress and relax. Most recently, a plant drop on the fourth floor of Hesler Biology was started to share free plant cuttings and propagules. The greenhouse staff members know how satisfying it is to be able to grow something green in your home or office. Because of this, they also have assisted with wellness initiatives on campus, providing plants for a residence hall mental health initiative called De-Stress to Success and to a campus-wide One Health awareness event in spring 2023.
The greenhouse staff and many volunteers also manage a wildflower trail at Dean’s Woods (Deanbrook Nature Area), located in South Knoxville. The trail is surrounded by 17 acres of hardwoods and is rich with spring ephemerals. Recently, The Dean’s Woods Foundation was created to support the upkeep, new plantings, and plant signage with the generous support of dentist Walter Fain (’70).
Greenhouses are open to UT students, staff, and faculty Monday through Friday, 9 a.m. to 4 p.m., with access through a UT ID card or phone. Please email Jeff Martin, jmarti90@utk.edu, for more information and for inquiries about how you can use the greenhouse space for research, teaching, and outreach. For weekly updates visit the greenhouse Instagram page, @utk_greenhouse.
Faculty Spotlight: Jessie Tanner
Faculty Spotlight: Jessie Tanner
Tree Frog Communication in Complex Environments
Jessie Tanner joined the University of Tennessee, Knoxville, in August 2022 as an assistant professor, dually appointed in the Department of Ecology and Evolutionary Biology and the Department of Psychology. An animal behaviorist, Tanner conducts research on the evolution of acoustic communication. She works with animals like frogs and crickets, in which males call or sing to attract females, who in turn use the sounds to choose mates. By experimentally manipulating the sounds and observing how females make mating decisions, the Tanner lab studies how communication is evolving in nature.
As a researcher, Tanner is especially interested in how acoustic communication systems evolve in realistically complex environments. One aspect of this environmental complexity is the noise in the raucous frog choruses that form in the spring. Another is the sheer number of call traits that vary in important ways; individuals may be forced to make less-than-ideal mating decisions if they can’t find all their desired traits in the same partner. Finally, individuals do not produce their calls the same way every time. Some traits are quite inconsistent within individuals, even over the span of a few minutes. A major focus of Tanner’s recent research has been understanding when and how this inconsistency might conceal the differences among individuals. All of these aspects of environmental complexity may affect how signals evolve.
Tanner is focusing on tree frogs native to East Tennessee, including the two closely related species of gray tree frogs. Before joining UT, she investigated mate choice in the livebearing, clonal fish called the Amazon molly; American black bears’ response to the noise made by drones; why some Pacific field cricket males in Hawaii have lost the ability to sing; and the changing shape of the baculum (penis bone) in rodent species native to Australia.
She was born and raised in Tulsa, Oklahoma, and her studies have taken her to such far-flung institutions as the University of Oklahoma (Norman), Université Bordeaux III Michel-de-Montaigne (Bordeaux, France), the University of Minnesota (Saint Paul), and the University of Western Australia (Perth).
Tanner’s interest in acoustic communication is defined very broadly, ranging from animal behavior to human language, linguistics, and music. She is an avid learner of Cherokee as a second language, holds a Bachelor of Arts in French, and participates in several communities of language learners and linguistics aficionados. A big fan of live music and an amateur guitarist, Tanner always has a song stuck in her head.
Faculty Spotlight: Sebastian Stockmaier
Faculty Spotlight: Sebastian Stockmaier
Bat Behavior and Cross-Species Transmission
Sebastian Stockmaier, who works at the intersection of behavioral and disease ecology, began as an assistant professor in the Department of Ecology and Evolutionary Biology in January 2023. He is interested in how host behaviors affect pathogen transmission and, in reverse, how pathogens affect host behaviors. Most of his work revolves around Neotropical bats in Panama, Belize, and (hopefully soon) Costa Rica. He uses the bats to understand social distancing behaviors and their costs and benefits, how pathogens manipulate host social behaviors, and whether we can predict and understand cross-species transmission by tracking small-scale interactions between different animals.
“My main study organism is common vampire bats. Vampire bats are fascinating animals because they are highly social and form social relationships almost equivalent to human friendships,” he explained. “We can use them to understand how the benefits of social relationships are traded-off against the costs of behaving sick (e.g., social withdrawal) but also, in general, how highly social animals deal with their sick conspecifics. In addition, we use them to understand animal-animal interactions that could potentially lead to cross-species transmission. They exclusively feed on blood. Cattle and other livestock are the vampire bat’s primary food source at many of our field sites. This really sets up a promising study system to understand and predict how fine-scale behavioral interactions could lead to cross-species transmission because vampire bats not only frequently interact with other animals, but are also known to transmit certain pathogens to them.”
Stockmaier is from a small mountain town in southern Germany, where he grew up spending a lot of time outside.
“I was always passionate about nature, and especially animals, but also grew an interest in infectious disease biology and immunology during my undergraduate studies in bioengineering. I was able to merge my interests during my master’s research at the University of Konstanz and the Max Planck Institute for Animal Behavior (formerly for Ornithology), where I studied wild bats. I then moved to the US and continued my work during my PhD at the University of Texas at Austin, and as a postdoctoral researcher at the Ohio State University before joining the EEB department at UT. I would describe myself as an empiricist, and so I am especially excited about all the collaborations with more quantitative-leaning researchers in the department and across campus.”
Stockmaier is passionate about science outreach and, especially, about bats.
“Unfortunately, bats have gotten a bad reputation in recent years, and I like to highlight to the public that concerns are in most cases unfounded and that they are fascinating animals that are an integral part of many ecosystems,” he said. “When I am not chasing bats through the forest, I enjoy hiking, camping, paddleboarding, and playing soccer. I am excited about all the public land to explore in and around Knoxville.”
New Faculty Spotlight: Claire Hemingway
New Faculty Spotlight: Claire Hemingway
Bats, Bees, and Their Dining Decisions
Claire Hemingway joined the University of Tennessee, Knoxville, in August 2023 as an assistant professor with a dual appointment in the Department of Ecology and Evolutionary Biology and the Department of Psychology. Hemingway is a cognitive ecologist interested in how animals make decisions in complex environments. She works primarily with two systems, bats and bees, to explore how animals find and choose what to eat.
Decades of research in humans have demonstrated that people make inconsistent decisions across time and contexts, failing to behave rationally. Instead, choices often are highly influenced by a decision-maker’s recent experience and the framing of the choice. Whether choosing a meal or a mate, animals also are often confronted with multiple options simultaneously. Hemingway’s research adopts principles from economics and psychology to investigate how animals evaluate and choose between multiple options based on their signal and reward properties. She explores how species differ in decision mechanisms based on their foraging behavior and other aspects of their ecology. She also asks how certain decision mechanisms may shape the targets of those decisions, such as floral signals and rewards.
Hemingway was born and raised in Austin, Texas. She has always been passionate about nature and animal behavior. As an undergraduate, she went to St. Edward’s University in Austin, Texas, where she began her research career investigating mate choice behaviors in livebearing fishes, such as guppies, mosquitofish, and sailfin mollies. She then completed a PhD at the University of Texas at Austin, where her dissertation research focused on decision-making strategies in Neotropical bats. For her dissertation research, she conducted all of her fieldwork at the Smithsonian Tropical Research Institute in Panama. She then went on to do post-doctoral research at the University of Texas at Austin, studying decision-making behaviors in bumblebees choosing between flowers that vary in their floral signals and rewards. In Tennessee, Hemingway is now focusing on several native bumblebee species, as well as continuing to conduct laboratory-based studies with captive bumblebee colonies. She will also continue to study Neotropical bats in Panama.
While not hanging out in jungles or meadows following bats and bees, Hemingway enjoys running, hiking, and camping. She has only just begun to explore all the local trails and parks close to Knoxville. She is also a huge fan of live music and is excited to explore the bluegrass music of East Tennessee.