Ecology & Evolutionary Biology

Author: artsciweb

Simberloff Honored by British Ecological Society

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Each year, the British Ecological Society (BES) recognizes 11 distinguished ecologists whose work has benefited the scientific community and society in general.

Daniel Simberloff, the Gore Hunger Professor of Environmental Science in the UT Department of Ecology and Evolutionary Biology, received an honorary membership – the Society’s highest honor – for his “exceptional contribution at the international level to the generation, communication, and promotion of ecological knowledge and solutions.”

“I have been an avid reader of BES journals since my earliest graduate school days,” Simberloff said. “My extensive research on Charles Elton led me to a greater appreciation of the leading role BES plays in shaping the direction of ecological research. I am humbled and deeply grateful that the Society would confer such an honor on me.”

Simberloff’s research focus is invasion biology, community composition, and the structure of organisms in specific features. One long-term project in Patagonia he has worked on involves invasive conifer trees and the introduction of deer, boar, and fungi. Almost a century ago, non-native tree species were introduced to a cleared section in the middle of a native forest in an attempt to establish a forestry industry on Isla Victoria, an island in the middle of Lake Nahuel Huapi. Only seven of the original species spread in number beyond the plantations.

“Our research shows that absence of suitable mycorrhizal fungi in the native forest keeps many of the non-native species from spreading,” Simberloff said. “Boar introduced in 1999, however, are exacerbating the invasion by rooting for fungal mycelium. Also, two species of deer introduced long ago may be aiding the spread.”

Simberloff became fascinated with nature during his childhood in rural Pennsylvania, but it was his time at Harvard College that got him hooked on ecology.

“I was seduced by the aesthetics and challenge of mathematics, but a non-majors biology course and an entomology course steered me back into biology and to the laboratory of Edward O. Wilson, who advised my doctorate: a test of the equilibrium theory of island biogeography with the arthropod communities of small mangrove islands,” Simberloff said. “This research and interactions with Wilson and Robert MacArthur, who served as a member of my doctoral committee, led me to a lifelong interest in the community level of organization – which species are found together, which are not found together, and why.”

Simberloff, along with Robin Chazdon, University of the Sunshine Coast, in Australia and Monica Turner, University of Wisconsin-Madison, joined the BES Honorary Membership roster, which includes British Ecologist Sir David Attenborough.

This year, there are winners across five continents, representing the international membership of the BES. Learn more about the 2023 BES award winners.

Investigating New Digital Authorities

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In the years since social media became part of our daily lives, an increased number of individuals are self-organizing online around identity, social topics, and various other interests. This transition leads to a new type of cultural authority and one that researchers are investigating to understand how the online human world interacts with the offline human world at both the individual and collective level. 

Sergey Gavrilets, Distinguished Professor in the UT Department of Ecology and Evolutionary Biology, received a grant from the John Templeton Foundation to research the emergence of these new digital authorities on social media. The $1.2 million grant is the largest Templeton Foundation award in UT history.

“I’ve always been puzzled by how presumably reasonable people can come up with completely different strong beliefs or understandings about the same events or processes that happened or are happening in different situations affecting their personal life or our society,” Gavrilets said. “Over the last couple of years, with the 2020 elections and COVID, these differences have become particularly striking and their real and potential consequences particularly dangerous.”

The big question he wants to answer? “How are contemporary social media changing human social and cultural evolution?”

Understanding How New Authorities Develop

Gavrilets and colleague Neil Johnson from the George Washington University will leverage recent work on online behaviors to build a new understanding of how these new authorities develop and function. They will look at how these new authorities contribute to cultural polarizations and how their efforts and impacts are influenced. 

“We will study the emergence of self-organized groups spouting extremism, hate, and vaccine hesitancy within and across social media platforms,” Gavrilets said. “We will look at their structure and try to understand how its composition defines who listens and how these new identity groups emerge.”

Gavrilets, a mathematical biologist whose work focuses on human social behavior, will borrow ideas and theoretical tools from ecology and evolutionary biology and apply them to human social behaviors online. 

“This work will not only help us to understand online human social behaviors better, but also how our attitudes and beliefs are shaped,” said Gavrilets, who also is the director of the Center for the Dynamics of Social Complexity at UT.

“Misinformation about science, climate change, vaccination, COVID, and political processes and events has a potential to affect the life, prosperity, and wellbeing of everyone in a negative way,” Gavrilets said. “By understanding how new social and cultural authorities are formed online, we can develop better policies for governments and businesses to counter misinformation and simultaneously promote public understanding of science-based policies aiming to improve our life and prosperity.”

To learn more, read the full project summary online. 

About the John Templeton Foundation

Founded in 1987, the John Templeton Foundation supports research and catalyzes conversations that inspire people with awe and wonder. They fund work on subjects ranging from black holes and evolution to creativity, forgiveness, and free will. They also encourage civil, informed dialogue among scientists, philosophers, theologians, and the public at large. Their aspiration is to help people create lives of meaning and purpose and to become a global catalyst for discoveries that contribute to human flourishing.

With an endowment of $3.8 billion and annual giving of approximately $140 million, the Foundation ranks among the 25 largest grantmaking foundations in the United States. Headquartered outside Philadelphia, their philanthropic activities have engaged all major faith traditions and extended to more than 57 countries around the world.

Ecology Professor Receives NSF Grant to Research Global Change Affecting Ecosystems

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Stephanie KivlinStephanie Kivlin, assistant professor in the UT Department of Ecology and Evolutionary Biology (EEB), and co-principal investigators, Susan Kalisz and Nick Smith, received a $3.58 million National Science Foundation (NSF) grant to fund collaborative research for their project “Defining the mechanisms and consequences of mutualism reorganization in the Anthropocene.”

Kivlin and her colleague Kalisz, EEB professor, received $2.33 million of the grant, while Smith, assistant professor in Department of Biological Sciences at Texas Tech University, received the remaining funding.

The five-year study will allow Kivlin and her colleagues to research the symbiotic relationships between plants and fungi and how global changes, including invasive species, affect them.

“Our current collaborative NSF integrative biology grant will investigate how invasive plants disrupt native plant and mycorrhizal fungal associations from small-scale nutrient fluxes to native plant health, composition, and ecosystem carbon and nutrient cycles,” Kivlin said.

The project builds off decades of Kalisz’s NSF-funded long-term research in environmental biology studies at the Trillium Trail in Pittsburgh that focused on the effects of the presence of garlic mustard, a highly invasive plant species, on native plant species.

“Plant invasions are one of the largest impacts of human land-use across Earth, but the effects of invasions on belowground processes have largely been unexplored. Our project will unearth these hidden effects so society can be better prepared to mitigate detrimental effects on native plants in the future,” Kivlin said.

There is not currently enough information about how interactions between plants and fungi respond to climate and land-use change because these interactions tend to be hidden and widely dispersed.

“Fundamental knowledge from our work will determine how global change will disrupt interactions among organisms in natural ecosystems. Many plants and animals, like humans, rely on their microbiome to survive and thus, it is crucial that we understand how these interactions will perform under future conditions,” Kivlin said.

Undergraduate students in underrepresented groups from rural Appalachia who otherwise would not have the opportunity to engage in research will be given the chance to do so. Students will conduct laboratory experiments at UT and will partake in field experiments in Pittsburgh.

–Story by Jessica Foshee

Dung beetle mothers protect their offspring from a warming world by digging deeper

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A road sign in Bursa, Turkey, warns drivers of the presence of dung beetles, stating ‘Attention! It may come out, don’t crush it please!’
Ugur Ulu/Anadolu Agency via Getty Images

Kimberly S. Sheldon, University of Tennessee

If the TV series “Dirty Jobs” covered animals as well as humans, it would probably start with dung beetles. These hardworking critters are among the insect world’s most important recyclers. They eat and bury manure from many other species, recycling nutrients and improving soil as they go.

Dung beetles are found on every continent except Antarctica, in forests, grasslands, prairies and deserts. And now, like many other species, they are coping with the effects of climate change.

I am an ecologist who has spent nearly 20 years studying dung beetles. My research spans tropical and temperate ecosystems, and focuses on how these beneficial animals respond to temperature changes.

Insects don’t use internally generated heat to maintain their body temperature. Adults can take actions such as moving to warmer or colder areas. However, earlier life stages such as larvae are often less mobile, so they can be strongly affected by changing temperatures.

But dung beetles appear to have a defense: I have found that adult dung beetles modify their nesting behaviors in response to temperature changes by burying their brood balls deeper in the soil, which protects their developing offspring.

Without dung beetles, the world would be messier and smellier.

Champion recyclers

It’s easy to joke about these busy insects, but by collecting and burying manure, dung beetles provide many ecological benefits. They recycle nutrients, aerate soil, lessen greenhouse gas emissions from cattle farming and reduce pest and parasite populations that harm livestock.

Dung beetles are also important secondary seed dispersers. Dung from other animals, such as bears and monkeys, contains seeds that the beetles bury underground. This protects the seeds from being eaten, makes them more likely to germinate and improves plant growth.

There are roughly 6,000 species of dung beetles around the world. Most feed exclusively on dung, though some will feed on dead animals, decaying fruit and fungi.

Some species use stars and even the Milky Way to navigate along straight paths. One species, the bull-headed dung beetle (Onthophagus taurus), is the world’s strongest insect, able to pull over 1,000 times its own body weight.

That strength comes in handy for dung beetles’ best-known behavior: gathering manure.

Rolling and tunneling

Most popular images of dung beetles show them collecting manure and rolling it into balls to spirit away. In fact, some species are rollers and others are tunnelers that dig into the ground under a dung pat, bring dung down into the tunnel and pack it into a clump or sphere, called a brood ball. The female then lays an egg in each brood ball and backfills the tunnel with soil. Rollers do the same once they get their dung ball safely away from the competition.

Two human fingers grasp a pingpong ball-size dung ball with a fingernail-size egg embedded in the surface
An egg is visible in the center of a brood ball from a female rainbow scarab beetle (Phanaeus vindex).
Kimberly Sheldon, CC BY-ND

When the egg hatches, the larva feeds on dung from the brood ball, pupates and emerges as an adult. It thus goes through complete metamorphosis – from egg to larva to pupa to adult – inside the brood ball.

Warmer temperatures produce smaller beetles

Dung beetle parents don’t provide care for their offspring, but their nesting behaviors affect the next generation. If a female places a brood ball deeper underground, the larva in the brood ball experiences cooler, less variable temperatures than it would nearer the surface.

This matters because temperatures during development can affect offspring survival and other traits, such as adult body size. If temperatures are too hot, offspring perish. Below that point, warmer, more variable temperatures lead to smaller-bodied beetles, which can affect the next generation’s reproductive success.

Smaller males can’t compete as well as larger males, and smaller females have lower reproductive output than larger females. In addition, smaller-bodied beetles remove less dung, so they provide fewer benefits to humans and ecosystems, such as nutrient cycling.

Beetles in the greenhouse

Climate change is making temperatures more variable in many parts of the world. This means that insects and other species have to handle not just warmer temperatures, but greater changes in temperature day to day.

To examine how adult dung beetles responded to the types of temperature shifts associated with climate change, I designed cone-shaped mini-greenhouses that would fit over 7-gallon buckets buried in the ground to their brims. Will Kirkpatrick, an undergraduate student in my lab, led the field trials.

We randomly placed a fertilized female rainbow scarab, Phanaeus vindex, in each greenhouse bucket and in the same number of uncovered buckets to serve as controls. Using temperature data loggers placed at four depths in the buckets, we verified that soil temperatures in “greenhouse” buckets were warmer and more variable than soil temperatures in uncovered buckets.

A large round beetle with red, green and gold shading
A male rainbow scarab dung beetle (Phanaeus vindex).
Dan Mele, CC BY-ND

We gave the beetles fresh cow dung every other day for 10 days and allowed them to make brood balls. Then we carefully dug through the buckets and recorded the number, depth and size of brood balls in each bucket.

Digging deeper

We found that beetle mothers in greenhouse environments created more brood balls overall, that these brood balls were smaller, and that these females buried their brood balls deeper in the soil than beetle mothers in control buckets. Brood balls in the greenhouses still ended up in areas that were slightly warmer than those in the control buckets – but not nearly as warm as if the beetle mothers had not altered their nesting behaviors.

A cone-shaped cover placed in a patch of dirt
A dung beetle greenhouse placed over a buried bucket of soil in the author’s field trial.
Kimberly Sheldon, CC BY-ND

However, by digging deeper, the adults fully compensated for temperature variation. There was no difference in the temperature variation experienced by brood balls in greenhouse buckets and control buckets. This reflects the fact that soil temperatures become increasingly stable with depth as the soil becomes more and more insulated from the changing air temperatures above it.

Our findings also hint at a possible trade-off between burial depth and brood ball size. Beetle mothers that dug deeper protected their offspring from temperature changes but provided less dung in their brood balls. This meant less nutrition for developing offspring.

Climate change could still affect adult dung beetles in ways we did not test, with consequences for the next generation. In future work, we plan to place brood balls of Phanaeus vindex and other species of dung beetles back into the greenhouse and control buckets at the depths at which they were buried so that we can see how the beetle offspring develop and survive.

So far, though, my colleagues and are encouraged to find that these industrious beetles can alter their behavior in ways that may help them survive in a changing world.The Conversation

Kimberly S. Sheldon, Associate Professor of Ecology and Evolutionary Biology, University of Tennessee

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Sheldon Publishes Research on Dung Beetles and Climate Change

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Assistant Professor Kimberly Sheldon published results from a recent study in Biology Letters that suggest adult dung beetles may be changing their behavior to partially buffer developing offspring from temperature changes related to climate change.

“I developed mini-greenhouses that raised the temperature average and variance in experimental buckets,” Sheldon said. “We put beetles in the buckets and recorded their behaviors, and we found that females buried their offspring farther in the soil to avoid warmer temperatures.”

Will Kirkpatrick, an undergraduate student researcher in the Sheldon Lab, ran the field component.

Read the full paper online in Biology Letters.

Russo Co-Authors Planting for Pollinators

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Assistant Professor Laura Russo is part of a research team that published findings from an experiment to provide evidenced-based recommendations for pollinator-friendly native perennials in eastern Tennessee.

Download the UT Institute of Agriculture Extension Publication: Planting for Pollinators in East Tennessee, authored by Virginia Sykes, Department of Plant Sciences, Karl McKim and Laura Russo, Department of Ecology and Evolutionary Biology, and Amani Khalil, Oak Ridge Institute for Science and Education.

New Research Suggests Heat Waves Could Lead to Avian Population Decline

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Liz DerryberryUnderstanding how birds respond to climate change is a critical area of research that Elizabeth Derryberry, associate professor in the UT Department of Ecology and Evolutionary Biology, and her colleagues are racing to understand, including the increased prevalence and intensity of heat waves. In a new study published online in Molecular Ecology, the researchers examined how heat impacts the behavior and physiology of Zebra finches.

“Most of what we know about the behavioral and physiological effects of heat comes from aquatic organisms or terrestrial cold-blooded animals, but heat waves could be a real problem for terrestrial birds and mammals too, especially if heat interferes with critical components of their reproductive behavior and physiology,” said Sara Lipshutz, assistant professor at Loyola University Chicago, former graduate student at UT, and first author on the publication. “We wanted to understand how that happens as a first step towards understanding how to manage these problems.”

Heat waves can be lethal for warm-blooded animals, but behavioral and physiological effects are missing from recent high-profile studies on climate change. The researchers wanted to know about sub-lethal effects of heat that do not kill animals, but still might impact their ability to adapt and thrive as the climate changes.

Lipshutz and colleagues exposed zebra finches to a four-hour heat challenge, similar to what wild birds might experience during the afternoon heat on a summer day. Zebra finches were selected for the study because these songbirds experience extreme temperature fluctuations in their native Australia.

The team measured heat effects on thermoregulatory behavior and looked specifically at how heat changed gene activity in tissues that are critical to reproduction – the testis that control fertility and a part of the brain that regulates singing, which is an essential mate-attraction behavior in birds. They discovered that heat altered the activity of hundreds of genes in the testis, but fewer in the brain, suggesting that the brain may be less responsive to extreme temperatures.

“At the same time, we found evidence that dopamine-related signaling was affected in the brain, meaning that even sub-lethal heat may change a bird’s ability to reproduce, via changes in motivational circuits for song production,” Lipshutz said. “If they can’t sing, or sing well, they aren’t going to breed.”

Bird populations have been dramatically declining over the past few decades, and male songbirds need to sing to attract a mate. Coupled with previous studies showing that birds sing less during heat, this project reveals potential underlying mechanisms by which heat may contribute to avian population declines.

“It’s really a triple-whammy,” said Derryberry, corresponding author on the publication. “Heat’s not only affecting their brains, but it also appears to affect testicular gene networks related to self-maintenance and sperm production. So, there’s potentially less motivation to sing, reduced gonadal function, and greater investment in self-maintenance, all of which can detract from successful reproduction.”

The study also provided some hopeful insights for birds and their ability to handle the threat of climate change. Males that panted more often during the heat challenge exhibited more limited effects on gene activity in the brain and testis.

“For a long time, researchers have reasoned that behavioral flexibility might be key for animals’ ability to handle novel environmental challenges,” said Kimberly Rosvall, associate professor of biology at IU Bloomington, whose lab oversaw that genomic side of this project. “We saw that some individuals better used behavioral thermoregulation to dissipate the physiological effects of heat. If animals are able to adjust their behavior. or if behavior can evolve to keep pace with climate change, birds may be able to adapt.”

According to Lipshutz, the results have important implications for sexual selection in a warming world as well.

“Some individuals, or even some species, may perform well under extreme temperatures,” she said. “That could influence both how thermal tolerance evolves and how behavior evolves too.”

Additional authors on the study are Clara Howell (former master’s student in Derryberry’s lab), Aaron Buechlein (bioinformatician, IU Center for Genomics and Bioinformatics) and Douglas B. Rusch (lead bioinformatician, IU Center for Genomics and Bioinformatics).

The researchers’ work was funded by U.S. National Science Foundation fellowship and published online May 14, 2022, in Molecular Ecology.

For the Love of Plants

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As you walk on the UT campus, you may see the large glass greenhouses overlooking Neyland Stadium. The University of Tennessee Department of Ecology and Evolutionary Biology greenhouses were first built in 1934 and have gone through multiple renovations. There are still plants from the original collection that are almost 100 years old now.

Recently, the UT Greenhouses received an extremely generous donation from Suzanne Herron and her late husband, Drew Herron. The collection included mostly succulents and cacti plants. Some of the plants are very rare and possess unique traits and modifications. UT Greenhouses were fortunate to receive Herron’s beloved collection.

“Drew Herron knew what UT Greenhouses mission is and he wanted to enhance our outreach and education by donating his collection,” said Jeff Martin, manager of UT Ecology and Evolutionary Biology Greenhouses. “These plants will also be a great addition to our teaching and research.” One example, according to Martin, is demonstrating convergent evolution, which occurs when organisms independently find their way to the same evolutionary solution for the same environmental problem

Martin also just made a donation of one of their own rare flowers to Zoo Knoxville. In July of 2021, the rare Amorphophallus titanum, or more commonly known as the corpse flower, bloomed on UT’s campus. The bloom of the corpse flower only occurs once every 7-10 years and lasts for about a day before wilting. As it blooms, the flower releases a putrid stench that becomes even more potent as the flower’s temperature rises to about 90 degrees Fahrenheit.

After seeing how the corpse flower bloom sparked excitement in the community, Martin chose to donate the flower to the zoo to be placed in the new Arc exhibit with the turtles. Martin hopes that by having the plant at the zoo, it will be able to reach a larger audience outside of East Tennessee. He wants this to be an opportunity to educate more people about the importance of plants and hope to share the positive impact the flower had on UT’s community. 

“We donated one to the zoo because I wanted to continue to share something as interesting and unique as the corpse flower,” Martin said. “We want to take advantage of opportunities we have to educate others about the importance of plants and the natural world. Anything that piques people’s interest in plants is excellent.”

–Story by Sarah Berry

Darwin Day Highlights Evolution Education

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This year, graduate students hosted Darwin Day UT, a series of events on campus to promote awareness of the importance of evolution to the study of biology and scientific research at UT and other institutions. Charles Darwin was born February 12, 1809. He is a critical figure in the history of evolutionary biology and during the week of his birthday, graduate students in the UT Department of Ecology and Evolutionary Biology celebrate his contributions to science.

Events throughout the week included Evolution Trivia, a graduate student research panel discussion, Darwin’s birthday party full of family fun in conjunction with the McClung Museum, and more. Students and faculty on campus may have also seen the large Darwin puppet mascot on the pedestrian walkway handing out flyers and prizes. These events were led by graduate students in the ecology and evolutionary biology department including Hope Ferguson, Wieteke Holthuijzen, Tara Empson, Nicole Lussier, Lauren Lyon, and Krista De Cooke. More than 300 people attended events throughout the week. 

“Understanding evolution is key to understanding our world. For over two decades, Darwin Day at UT has been a fun, inclusive way to educate people about the topic,” said Dr. Brian O’Meara, faculty advisor for Darwin Day.

The tradition of Darwin Day celebrations at UT go back to 1997. UT prides itself on being among the most active institutions in celebrating and promoting evolution education, which is possible with support from several units at UT.

“Darwin Day has historically been an interdepartmental event with generous donations, volunteers, and coordinators from other UT departments. It’s been great working with colleagues across the campus to think of innovative activities, especially during the pandemic,” said Krista De Cooke, Darwin Day President 2020-2022. 

–Story by Sarah Berry

 

Gross Investigates Relationship Between Climate Change Beliefs and Risk

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Louis GrossLouis Gross, Chancellor’s Professor in the UT Department of Ecology and Evolutionary Biology, recently co-authored an article, “Determinants of Emissions Pathways in the Coupled Climate-Social System” published in the journal Nature, which investigates whether or not there is a link between humans’ belief in climate change risk and the Earth’s changing climate. 

“This research indicates that there are significant feedbacks between the physical climate system and human behavioral, societal and economic responses that affect our ability to project future climate,” said Gross. “Our research demonstrates that these feedbacks can somewhat reduce the negative impacts of climate change that are projected to occur when the feedback to human behavior and societal responses are not taken into account.”

This research focuses on how social, political, and technological factors are all critical for predicting the degree our climate will change overtime. Gross explains how this research can be a driving force for society to take more progressive steps to help reduce the negative impact of climate change. People’s beliefs in climate change and its relevance can affect the policies in place. This along with other factors will ultimately have an impact on the earth’s climate.

This research was supported by the National Institute for Mathematical and Biological Synthesis (NIMBioS), which is headquartered at UT. It was funded by the National Science Foundation with additional support from UT.

“This research is part of a set of collaborative efforts which began several years ago through the support of the NIMBioS. It fostered a highly interdisciplinary group of researchers, with backgrounds in economics, public policy, psychology, mathematics, ecology and climate science, which allowed this effort to be successful,” said Gross.

The collaborations established through Gross and his colleague’s research is continuing using new models, alternate theories, and approaches to enhance climate projections that account for societal responses.

–Story by Sarah Berry