Following the people and events that make up the research community at Duke

Category: Biology Page 2 of 27

New Blogger Camila Cordero: Renaissance First-Year

My name is Camila Cordero, and for those who know Spanish: yes, my last name does mean lamb. I’m a Hispanic female, born and raised in Miami, Florida. Living in Miami, one can think of many stereotypes (don’t pretend). You have the terrible traffic, the apocalyptic heat, and the international sensation, “Despacito” played everywhere.

Having a civil engineer as a father and an agriculture specialist as a mother, I became the best of both worlds as someone who now seeks to pursue a degree in Biomedical Engineering, interested in following pre-health as well.

To say I have a ‘passion’ in the sciences would be an understatement. Ever since I was a young person, I have always been curious about the world around me; questioning why things happen, how things occur, and what composes of things. It came to no surprise that in elementary school, I was already competing in multiple science competitions, broadening my range of knowledge. At first, I was drawn into the world of cartography and mechanical engineering– drawing profiles and building Rube Goldberg machines at the young age of 11. Yet, in just a span of a few years, I continued my journey into the unknowns of science, later figuring out that my true calling falls in the world of biology.

But don’t think I cut myself short there! Having such an excitement to be taught and taking every opportunity to acquire a new skill, I can see myself in the future as a Renaissance woman. Just as easy as it is for me to sketch you a beautiful drawing, I can also figure skate on ice, talk to you in Spanish or Greek, and change a NASCAR stock car tire. From here, who knows what else I will do in these next four years at Duke!

Writing for the Duke Research Blog, I seek to learn yet another ability: to write. Having written short stories for writing competitions and speeches in school, I seek to perfect this skill through the blog. Not only will I practice my writing, but I will continue to explore the world of science that I love so deeply with the help of others. I hope that with my writing, I will be able to reach out to the public and teach them about the scientific research that can impact the world for the better.

Post by Camila Cordero, Class of 2025

New Blogger Sophie Cox: Keep Asking Questions

Typing with one hand, especially my left hand, is not easy, but my right hand is currently occupied by freeze-dried mealworms and, momentarily, by a chittering wild bird.

My eagle-eyed supervisor is a Carolina wren, South Carolina’s official state bird.

“You have babies, don’t you?” I mutter as a small, brown bird with a white eyestripe wraps her long toes around my fingers.

She doesn’t answer–she never does–but she flutters repeatedly to my socked feet and from there to my hand, where she selects a mealworm and then flies to a flower box on my neighbor’s mailbox.

This bird and her mate are the pair of Carolina wrens who have spent the past year training me to hand-feed them. Life hack: if you’re being cornered by wild birds every time you step outside, I suggest keeping a bag of dried mealworms in your pocket.

I want to investigate the flower box, but I don’t want to betray the trust I’ve worked so hard to build. Instead, I wait until my little friend finishes her ritual before approaching the mailbox.

Among the fake hydrangea blossoms, I see a scruffy head poking out. Judging by its size, the youngster looks about ready to leave the nest. With a smile, I turn and walk away.

Along with observing wildlife, I enjoy reading, writing, playing board games, and spending time outside.

My name is Sophie, and I’m a freshman at Duke. At home in upstate South Carolina, I can often be found smearing fruity, fermenting moth bait onto tree trunks at dusk or curled up in a hammock swing with a good book while the Carolina wrens do their best to distract me.

They each have their own personalities (which is partly how I tell them apart), but both birds strike me as curious and even intelligent.

Lately, I’ve been wondering if Carolina wrens belong on the growing list of animals believed to possess theory of mind, the ability to understand mental states and to recognize that others’ thoughts and beliefs can differ from one’s own.

I have always associated the natural world with a sense of wonder that borders on enchantment.

Perhaps unsurprisingly, I plan to major in biology. My lifelong aspiration to study science hasn’t faded, but science should be accessible to everyone, scientists or not. That is partly why I want to work for Duke’s research blog.

If the coronavirus pandemic has taught us anything, it’s the importance of having access to accurate information we can trust. Too often, data is manipulated and obscured, twisting facts and turning science into a political minefield. That should never be acceptable. My favorite news
sources are those that effectively bridge the gap between academia and the general public, providing information that is digestible and engaging without sacrificing scientific integrity.

Judging by the articles I have read, Duke’s research blog has a similar mission, and it’s a mission I firmly believe in.

Science is full of unanswered questions. At its simplest, my goal for the future is the same as it was ten years ago: to answer some of those questions.

This summer, I worked as a counselor and nature instructor at a residential summer camp. Campers often approached me throughout the day to enthusiastically describe their encounters with click beetles, squirrels, and frogs. I saw in their eyes the same exhilaration I feel when the Carolina wrens’ amber eyes meet mine or when a shimmery, pale golden moth flutters across my pajamas and then disappears soundlessly into the night, as beautiful and ephemeral as a
moonbeam.

One young boy, a seven-year-old who reminded me of myself at his age, was fascinated by my field guide to insects and spiders of North America. Again and again, he’d point to an insect or spider or worm, then hand the field guide to me and wait for me to find the right page. At one point, he even retrieved the book from my backpack. I don’t know if he could read, but he knew what the book was for, and he cared. He could neither hear nor speak, but maybe, in the end, it didn’t matter. You don’t need words to flip over stones and marvel at the life hidden beneath.

People want scientific knowledge. Studying science — and not just as scientists — brings us so tantalizingly close to the mysterious, the undiscovered, the unknown. Science is more than petri dishes, graphs, and Latin jargon. It is a world full of questions waiting to be asked. In my own scientific writing, mostly in the form of nature journals, I strive to be methodical but not impersonal. My goal as a blogger is similar: to be accurate and objective without sacrificing the mystery and excitement that makes science so engaging to begin with.

After college, I hope to pursue ecological field research. In the meantime, I’ll keep exploring. I’ll keep flipping over stones. I’ll keep talking to the wrens, even if they never talk back, and wondering what they’re thinking when their gaze meets mine. In short, I’ll keep asking questions. I think you should, too.

Post by Sophie Cox, Class of 2025

New Blogger Skylar Hughes: ‘Up for the Challenge’

When I was a young girl, My mother once explained to me the importance of a first impression. “You can only make it once, after all,” she’d say. Here I am writing this introduction for you guys, and her words echo in my mind, so I’ll give it my best shot.

Senior pictures, time flies!

Hi, my name is Skylar Hughes, and I’m a part of the class of 2025. Atlanta, Georgia, is where I call home, and from my slang to my walk, it’s quite obvious where I grew up. I’m the person who will talk to everyone and is not at all afraid to speak her mind. A random fun fact about me is that I was actually on the Ellen Show in January!! (kind of cool, right?) It still feels unreal that I am here, and you will most likely see me wandering around lost one day like the freshman I am. My major is undecided, but currently I am between Marine Science and Public Policy. (confused isn’t even the word. )

I’m still in shock from this… https://youtu.be/OivXTYYiUj4

Marine science was my first love, the major that I’ve had a crush on since middle school, and invested countless hours researching online and through documentaries. I even went to a Duke TIP marine science program in the Gulf of Mexico my sophomore year of high school and loved every second of it. I’ve watched every episode of Deep Blue on National Geographic and probably know more than a person should about coral reefs. But public policy? That was like my celebrity crush, the major I eyed from a distance and really admired, but never had the privilege to closely interact with. I remember watching figures like Alexandria Ocasio-Cortez and Stacey Abrams dominate the field with their intelligence, being the change they wanted to see in their communities, and I was hooked. As a teenager, I often found myself frustrated with government decisions and realized that public policy gave me the chance to make genuine change. I was sold.

My High School Graduation!

So now here I am at Duke, which maintains an outstanding program for marine science AND public policy, and I am like a kid in a candy store. Along with hoping to figure my major out this year, I’m also planning on being involved with the Black Student Alliance here at Duke, as well as joining Duke’s Climate Change Coalition, and volunteering at the Geer Street Learning Garden.

For me, research blogs are a brilliant way to reach the masses with reliable information, research, and content that can be trusted, which is profoundly important to me. Education is the only process by which growth is made. Without education, we’re, in essence, doomed for retrogression. Education arms people with a weapon that cannot be stolen, one that can not only rid them of their current circumstances but be a guiding light towards their desired ones.

Education refines new ideas, which are the only reasons man is not still living in caves and figuring out fire. The education of one can be utilized to educate another, creating a snowball effect of intellect that cannot be restrained. An educated population leads to educated decisions in society, which leads to educated leaders in office, leading to more authentic community at Duke, in Durham, and beyond.

Sunset view from one of my favorite spots in Atlanta: Stone Mountain!

I take great pleasure in writing, and it was one of the few activities in school that I viewed as a stress reliever instead of a stressor. In a society as dynamic and saturated as the one we’re submerged in, research blogs are essential. Durham represents such a culturally rich and diverse community with so many stories to tell and issues to be brought to light. There are people from all ranges of socioeconomic status, gender, race, and religion, with narratives that are worth their weight in gold. I can only imagine the growth as an intellectual and the valuable experience gained with this position, and I am up for the challenge.

Post by Skylar Hughes, Class of 2025

Introducing: The Duke Space Initiative

NASA

Engineers, medical students, ecologists, political scientists, ethicists, policymakers — come one, come all to the Duke Space Initiative (DSI), “the interdisciplinary home for all things space at Duke.”

At Duke Polis’ “Perspectives on Space: Introducing the Duke Space Initiative” on Sept. 9, DSI co-founder and undergraduate student Ritika Saligram introduced the initiative and moderated a discussion on the current landscape of space studies both at Duke and beyond.

William R. & Thomas L. Perkins Professor of Law Jonathan Wiener began by expressing his excitement in the amount of interest he’s observed in space at Duke. 

One of these interested students was Spencer Kaplan. Kaplan, an undergraduate student studying public policy, couldn’t attend Wiener’s Science & Society Dinner Dialogue about policy and risk in the settlement of Mars. Unwilling to miss the learning opportunity, Kaplan set up a one-on-one conversation with Wiener. One thing led to another: the two created a readings course on space law — Wiener hired Kaplan as a research assistant and they worked together to compile materials for the syllabus — then thought, “Why stop there?” 

Wiener and Kaplan, together with Chase Hamilton, Jory Weintraub, Tyler Felgenhauer, Dan Buckland, and Somia Youssef, created the Bass Connections project “Going to Mars: Science, Society, and Sustainability,” through which a highly interdisciplinary team of faculty and students discussed problems ranging from the science and technology of getting to Mars, to the social and political reality of living on another planet. 

The team produced a website, research papers, policy memos and recommendations, and a policy report for stakeholders including NASA and some prestigious actors in the private sector. According to Saligram, through their work, the team realized the need for a concerted “space for space” at Duke, and the DSI was born. The Initiative seeks to serve more immediately as a resource center for higher education on space, and eventually as the home of a space studies certificate program for undergraduates at Duke. 

Wiener sees space as an “opportunity to reflect on what we’ve learned from being on Earth” — to consider how we could avoid mistakes made here and “try to do better if we settle another planet.” He listed a few of the many problems that the Bass Connections examined. 

The economics of space exploration have changed: once, national governments funded space exploration; now, private companies like SpaceX, Blue Origin, and Virgin Galactic seek to run the show. Space debris, satellite and launch junk that could impair future launches, is the tragedy of the commons at work — in space. How would we resolve international disputes on other planets and avoid conflict, especially when settlements have different missions? Can we develop technology to ward off asteroids? What if we unintentionally brought microorganisms from one planet to another? How will we make the rules for the settlement of other planets?

These questions are vast — thereby reflecting the vastness of space, commented Saligram — and weren’t answerable within the hour. However, cutting edge research and thinking around them can be found on the Bass Connections’ website.

Earth and Climate Sciences Senior Lecturer Alexander Glass added to Wiener’s list of problems: “terraforming” — or creating a human habitat — on Mars. According to Glass, oxygen “isn’t a huge issue”: MOXIE can buzz Co2 with electricity to produce it. A greater concern is radiation. Without Earth’s magnetosphere, shielding of some sort will be necessary; it takes sixteen feet of rock to produce the same protection. Humans on Mars might have to live underground. 

Glass noted that although “we have the science to solve a lot of these problems, the science we’re lagging in is the human aspects of it: the psychological, of humanity living in conditions like isolation.” The engineering could be rock solid. But the mission “will fail because there will be a sociopath we couldn’t predict beforehand.”

Bass Connections project leader and PhD candidate in political science Somia Youssef discussed the need to examine deeply our laws, systems, and culture. Youssef emphasized that we humans have been on Earth for six million years. Like Wiener, she asked how we will “apply what we’ve learned to space” and what changes we should make. How, she mused, do prevailing ideas about humanity “transform in the confines, the harsh environment of space?” Youssef urged the balancing of unity with protection of the things that make us different, as well as consideration for voices that aren’t being represented.

Material Science Professor, Assistant Professor of Surgery, and NASA Human System Risk Manager Dr. Dan Buckland explained that automation has exciting potential in improving medical care in space. If robots can do the “most dangerous aspects” of mission medical care, humans won’t have to. Offloading onto “repeatable devices” will reduce the amount of accidents and medical capabilities needed in space. 

Multiple panelists also discussed the “false dichotomy” between spending resources on space and back home on Earth. Youssef pointed out that many innovations which have benefited (or will benefit) earthly humanity have come from the excitement and passion that comes from investing in space. Saligram stated that space is an “extension of the same social and policy issues as the ones we face on Earth, just in a different context.” This means that solutions we find in our attempt to settle Mars and explore the universe can be “reverse engineered” to help Earth-dwelling humans everywhere.

Saligram opened up the panel for discussion, and one guest asked Buckland how he ended up working for NASA. Buckland said his advice was to “be in rooms you’re not really supposed to be in, and eventually people will start thinking you’re supposed to be there.” 

Youssef echoed this view, expressing the need for diverse perspectives in space exploration. She’s most excited by all the people “who are interested in space, but don’t know if there’s enough space for them.”

If this sounds like you, check out the Duke Space Initiative. They’ve got space.

Post by Zella Hanson

Two Ways to Weird: How Whale Noses Moved to the Top of Their Head

A blue whale skeleton suspended in London’s Natural History Museum

Odd skulls are nothing new to V. Louise Roth, a professor in the Department of Biology. Much of her research centers on how animals’ shapes and sizes evolve and develop, so weirdly shaped bones are at the core of her work. But when Ph.D. student Rachel Roston drew her attention to the peculiarities of whale skulls, even Roth was astounded.

“There are some pretty weird mammal skulls out there,” Roth said. “I have studied morphological development in elephants, which are also kind of a crazy choice, but in terms of which bone goes where I think cetaceans are the weirdest ones.”

Cetaceans are the group that includes baleen whales – such as humpback whales – and toothed whales – such as dolphins and killer whales. Unlike almost all other vertebrate animals, cetaceans don’t breathe out of their mouths or from a nose placed in front of their face, but from a blowhole located on top of their head.

How did it get up there?

Rachel Roston, a graduate student in the Duke Biology department, recently published a paper with Professor Louise Roth, about some of the ways dolphin, whale and porpoise skulls break the rules of anatomy.

A new study published in the Journal of Anatomy by Roth and Roston, now a postdoctoral researcher at the University of Washington, reveals how whale and dolphin skulls undergo a complete transformation through their embryonic and fetal development, resulting in a re-orientation of their nasal passages.

What’s more, there’s not just one way to do it: baleen whales and toothed whales move their nostrils to the tops of their heads in two very different ways.

“It’s not just that they are developing the same thing in different ways,” said Roston, who led this work as part of her Ph.D. in Biology at Duke. “Looking from the outside of the body all you see is that both of them have their nose on the top of their head, but when you look inside their skulls, they are actually totally different blowholes.”

A toothed whale clears its blowhole. Photo by Friedrich Frühling

To figure out which bone went where and in which way, Roston looked at CT scans of baleen and toothed whales’ embryos in different stages of development and drew a dotted timeline of anatomical changes through the animals’ development.

Early-stage embryos look very much alike in most vertebrate animals: small, with a disproportionally large head, big eyes and oral and nasal cavities in the front of their face. As the embryos develop, they take different paths and become more and more similar to their own species.

Most of them keep their noses and their mouths in front of their face, but dolphins and whales transform their whole heads to change the direction of their nasal passage while keeping the snout facing forward.

“We think of the nostrils as something you find at the tip of the snout,” Roth said. “But whales go through some key changes in bone orientation that decouple one from the other.”

“It’s like looking at a cubist Picasso painting,” Roston said. “The eyes, nose and mouth are all there, but their relationships to each other are completely distorted.”

Whale embryos at different developmental stages. The white arrow shows how the nasal cavity shifts position through embryonic development.

This internal shuffling requires that the parts forming the roof of the embryo’s mouth move away from those that form its nasal passage. Initially parallel in small young embryos, they end up at an angle of about 45 degrees in baleen whales. In toothed whales this final angle is even wider, closer to 90 degrees.

In baleen whales, a key rotation happens at the back of the skull, where it meets the spine. Rather than being perpendicular to the ground, as in the head of a dog, the back of the skull is tilted forward towards the snout.

In toothed whales, the point of inflexion for this rotation is in the middle of the head. A bone in the center of the skull changes shape, curving upwards as the nasal passage ends facing up.

Roston and Roth both say that museum collections and non-destructive scanning techniques, such as CT scans, were key for this project because whale embryo specimens are difficult to come by. When a gravid female dies, small embryos often go unnoticed in their mother’s massive carcass. But older fetuses are larger than your typical sedan, making them difficult to preserve intact and store in museums. The few specimens found in museums must therefore be studied with the proverbial velvet gloves, or, in this case, CT scans.

“In science you always question ‘how come no one’s done this before?’” Roston said. “Here, it was because specimens are precious, so you don’t want to cut them up and destroy them.”

“Sometimes we’re looking at museum specimens that are 100 years old. This was an opportunity to describe them in a way that I hope will still be useful 100 years from now.”

Read more about weird whale skulls.

The research was funded by Duke University. Roston has also been supported by the National Institutes of Health.

CITATION: “Different Transformations Underlie Blowhole and Nasal Passage Development in a Toothed Whale (Odontoceti: Stenella attenuata) and a Baleen Whale (Mysticeti: Balaenoptera physalus),” Rachel A. RostonV. Louise Roth, Journal of Anatomy. DOI: 10.1111/joa.13492

Post by Marie Claire Chelini PhD, Duke Biology

In Drawers of Old Bones, New Clues to the Genomes of Lost Giants

DNA extracted from a 1,475-year-old jawbone reveals genetic blueprint for one of the largest lemurs ever.

By teasing trace amounts of DNA from this partially fossilized jawbone, nearly 1,500 years after the creature’s death, scientists have managed to reconstruct the first giant lemur genome. Credit: University of Antananarivo and George Perry, Penn State

If you’ve been to the Duke Lemur Center, perhaps you’ve seen these cute mouse- to cat-sized primates leaping through the trees. Now imagine a lemur as big as a gorilla, lumbering its way through the forest as it munches on leaves.

It may sound like a scene from a science fiction thriller, but from skeletal remains we know that at least 17 supersized lemurs once roamed the African island of Madagascar. All of them were two to 20 times heftier than the average lemur living today, some weighing up to 350 pounds.

Then, sometime after humans arrived on the island, these creatures started disappearing.

The reasons for their extinction remain a mystery, but by 500 years ago all of them had vanished.

Coaxing molecular clues to their lives from the bones and teeth they left behind has proved a struggle, because after all this time their DNA is so degraded.

But now, thanks to advances in our ability to read ancient DNA, a giant lemur that may have fallen into a cave or sinkhole near the island’s southern coast nearly 1,500 years ago has had much of its DNA pieced together again. Researchers believe it was a slow-moving 200-pound vegetarian with a pig-like snout, long arms, and powerful grasping feet for hanging upside down from branches.

A single jawbone, stored at Madagascar’s University of Antananarivo, was all the researchers had. But that contained enough traces of DNA for a team led by George Perry and Stephanie Marciniak at Penn State to reconstruct the nuclear genome for one of the largest giant lemurs, Megaladapis edwardsi, a koala lemur from Madagascar.

Ancient DNA can tell stories about species that have long since vanished, such as how they lived and what they were related to. But sequencing DNA from partially fossilized remains is no small feat, because DNA breaks down over time. And because the DNA is no longer intact, researchers have to take these fragments and figure out their correct order, like the pieces of a mystery jigsaw puzzle with no image on the box.

Bones like these are all that’s left of Madagascar’s giant lemurs, the largest of which weighed in at 350 pounds — 20 times heftier than lemurs living today. Credit: Matt Borths, Curator of the Division of Fossil Primates at the Duke Lemur Center

Hard-won history lessons

The first genetic study of M. edwardsi, published in 2005 by Duke’s Anne Yoder, was based on DNA stored not in the nucleus — which houses most of our genes — but in another cellular compartment called the mitochondria that has its own genetic material. Mitochondria are plentiful in animal cells, which makes it easier to find their DNA.

At the time, ancient DNA researchers considered themselves lucky to get just a few hundred letters of an extinct animal’s genetic code. In the latest study they managed to tease out and reconstruct some one million of them.

“I never even dreamed that the day would come that we could produce whole genomes,” said Yoder, who has been studying ancient DNA in extinct lemurs for over 20 years and is a co-author of the current paper.

For the latest study, the researchers tried to extract DNA from hundreds of giant lemur specimens, but only one yielded enough useful material to reconstitute the whole genome.

Once the creature’s genome was sequenced, the team was able to compare it to the genomes of 47 other living vertebrate species, including five modern lemurs, to identify its closest living relatives. Its genetic similarities with other herbivores suggest it was well adapted for grazing on leaves.

Despite their nickname, koala lemurs weren’t even remotely related to koalas. Their DNA confirms that they belonged to the same evolutionary lineage as lemurs living today.

To Yoder it’s another piece of evidence that the ancestors of today’s lemurs colonized Madagascar in a single wave.

Since the first ancient DNA studies were published, in the 1980s, scientists have unveiled complete nuclear genomes for other long-lost species, including the woolly mammoth, the passenger pigeon, and even extinct human relatives such as Neanderthals.

Most of these species lived in cooler, drier climates where ancient DNA is better preserved. But this study extends the possibilities of ancient DNA research for our distant primate relatives that lived in the tropics, where exposure to heat, sunlight and humidity can cause DNA to break down faster.

“Tropical conditions are death to DNA,” Yoder said. “It’s so exciting to get a deeper glimpse into what these animals were doing and have that validated and verified.”

See them for yourself

Assembled in drawers and cabinets cases in the Duke Lemur Center’s Division of Fossil Primates on Broad St. are the remains of at least eight species of giant lemurs that you can no longer find in the wild. If you live in Durham, you may drive by them every day and have no idea. It’s the world’s largest collection.

In one case are partially fossilized bits of jaws, skulls and leg bones from Madagascar’s extinct koala lemurs. Nearby are the remains of the monkey-like Archaeolemur edwardsi, which was once widespread across the island. There’s even a complete skeleton of a sloth lemur that would have weighed in at nearly 80 pounds, Palaeopropithecus kelyus, hanging upside down from a branch.

Most of these specimens were collected over 25 years between 1983 and 2008, when Duke Lemur Center teams went to Madagascar to collect fossils from caves and ancient swamps across the island.

“What is really exciting about getting better and better genetic data from the subfossils, is we may discover more genetically distinct species than only the fossil record can reveal,” said Duke paleontologist Matt Borths, who curates the collection. “That in turn may help us better understand how many species were lost in the recent past.”

They plan to return in 2022. “Hopefully there is more Megaladapis to discover,” Borths said.

A fossil site in Madagascar. Courtesy of Matt Borths, Duke Lemur Center Division of Fossil Primates

CITATION: “Evolutionary and Phylogenetic Insights From a Nuclear Genome Sequence of the Extinct, Giant, ‘Subfossil’ Koala Lemur Megaladapis Edwardsi,” Stephanie Marciniak, Mehreen R. Mughal, Laurie R. Godfrey, Richard J. Bankoff, Heritiana Randrianatoandro, Brooke E. Crowley, Christina M. Bergey, Kathleen M. Muldoon, Jeannot Randrianasy, Brigitte M. Raharivololona, Stephan C. Schuster, Ripan S. Malhi, Anne D. Yoder, Edward E. Louis Jr, Logan Kistler, and George H. Perry. PNAS, June 29, 2021. DOI: 10.1073/pnas.2022117118.

In the World Capital of Vanilla Production, Nearly Three out of Four Farmers Say They Don’t Have Enough to Eat

A new study investigates why and what they can do about it

Madagascar, famous for its lemurs, is home to almost 26 million people. Despite the cultural and natural riches, Madagascar is one of the poorest countries in the world. Over 70% of Malagasy people are farmers, and food security is a constant challenge. Rice is the most important food crop, but lately an internationally-prized crop has taken center stage: vanilla. Most of the world’s best quality vanilla comes from Madagascar. While most Malagasy farmers live on less than $2 per day, selling vanilla can make some farmers rich beyond their dreams, though these profits come with a price, and a new study illustrates it is not enough to overcome food insecurity.

In a paper published June 25, 2021 in the journal Food Security, a team of scientists collaborating between Duke University and in Madagascar set out to investigate the links between natural resource use, farming practices, socioeconomics, and food security. Their recently published article in the journal Food Security details intricate interactions between household demographics, farming productivity, and the likelihood of experiencing food shortages.

Vanilla beans, Wikimedia Commons

The team interviewed almost 400 people in three remote rural villages in an area known as the SAVA region, an acronym for the four main towns in the region: Sambava, Andapa, Vohemar, and Antalaha. The Duke University Lemur Center has been operating conservation and research activities in the SAVA region for 10 years. By partnering with local scientists, the team was able to fine-tune the way they captured data on farming practices and food security. Both of the Malagasy partners are preparing graduate degrees and expanding their research to lead the next generation of local scientists.

Farmers harvesting the rice fields in Madagascar. Credit: Wikimedia Commons.

The international research team found that a significant proportion of respondents (up to 76%) reported that they experienced times during which did not have adequate access to food during the previous three years. The most common cause that they reported was small land size; most respondents estimated they owned less than 4 hectares of land (<10 acres), and traditional farming practices including the use of fire to clear the land are reducing yields and leading to widespread erosion. The positive side is that the more productive the farm, especially in terms of rice and vanilla harvests, the lower the probability of food insecurity. There was an interaction between rice and vanilla harvests, such that those farmers that produced the most rice had the lowest probability of food insecurity, even when compared to farmers who grew more vanilla but less rice. Though vanilla can bring in a higher price than rice, there are several factors that make vanilla an unpredictable crop.

The vanilla market is subject to extreme volatility, with prices varying by an order of magnitude from year to year. Vanilla is also a labor- and time-intensive crop; it requires specific growing conditions of soil, humidity, and shade, it takes at least 3 years from planting to the first crop. Without the natural pollinators in its home range of Mexico, Malagasy vanilla requires hand pollination by the farmers, and whole crops can be devastated by natural disasters like disease outbreaks and cyclones. Further, the high price of vanilla brings with it ‘hot spending,’ resulting in cycles of boom and bust for impoverished farmers. Because of the high price, vanilla is often stolen, which leads farmers to spend weeks in their fields guarding the vanilla from thieves before harvesting. It also leads to early harvests, before the vanilla beans have completely ripened, which degrades the quality of the final products and can exacerbate price volatility.

In addition to the effects of farming productivity on the probability of food insecurity, the research revealed that household demographics, specifically the number of people living in the household, had an interactive effect with land size. Those farmers that had larger household sizes (up to 10 in this sample) had a higher probability of experiencing food insecurity than smaller households, but only if they had small landholdings. Those larger families that had larger landholdings had the lowest food insecurity. These trends have been documented in many similar settings, in which larger landholdings require more labor, and family labor is crucial to achieving food sovereignty.

The results have important implications for sustainable development in this system.  The team found that greater rice and vanilla productivity can significantly reduce food insecurity. Therefore, a greater emphasis on training in sustainable, and regenerative, practices is necessary. There is momentum in this direction, with new national-level initiatives to improve rice production and increase farmers’ resilience to climate change. Further, many international aid organizations and NGOs operating in Madagascar are already training farmers in new, regenerative agriculture techniques. The Duke Lemur Center is partnering with the local university in the SAVA region to develop extension services in regenerative agriculture techniques that can increase food production while also preserving and even increasing biodiversity. With a grant from the General Mills, the Duke Lemur Center is developing training modules and conducting workshops with over 200 farmers to increase the adoption of regenerative agriculture techniques.

Further, at government levels, improved land tenure and infrastructure for securing land rights is needed because farmers perceive that the greatest cause of food insecurity is their small landholdings. Due to the current land tenure infrastructure, securing deeds and titles to land is largely inaccessible to rural farmers. This can lead to conflicts over land rights, feelings of insecurity, and little motivation to invest in more long-term sustainable farming strategies (e.g., agroforestry). By improving the ability of farmers to secure titles to their land, as well as access agricultural extension services, farmers may be able to increase food security and productivity, as well as increased legal recognition and protection.

To move forward as a global society, we must seek to achieve the United Nation (UN) Sustainable Development Goals (SDGs). One of the SDGs is Goal #2, Zero Hunger. There are almost one billion people in the world who do not have adequate access to enough safe and nutritious food. This must change if we expect to develop sustainably in the future. Focusing on some of the hardest cases, Madagascar stands out as a country with high rates of childhood malnutrition, prevalence of anemia, and poverty. This year, more than one million people are negatively impacted by a three-year drought that has resulted in mass famine and a serious need for external aid. Sadly, these tragedies occur in one of the most biodiverse places on earth, where 80-90% of the species are found no where else on earth. This paradox results in a clash between natural resource conservation and human wellbeing.

Achieving the UN’s SDGs will not be easy; in fact, we are falling far short of our targets after the first decade. The next ten years will determine if we meet these goals or not, and our collective actions as a global society will dictate whether we transform our society for a sustainable future or continue with the self-destructive path we have been following. Further research and interventions are still needed to conserve biodiversity and improve human livelihoods.

Learning Something Surprising About “SuperLearners”

The discovery of a signaling pathway in the brain that could make mice into ‘superlearners’ understandably touched off a lot of excitement a few years back.

But new work led by Duke neurologist and neuroscientist Nicole Calakos MD PhD suggests there’s more to the story of the superlearner chemical pathway than anybody realized.

A genetically-enhanced ‘smart mouse’ doing some important work. (Boston University)

In a study led by postdoctoral researchers Ashley Helseth and Ricardo Hernandez-Martinez,  the Calakos lab developed a new tool to visualize activity of this Integrated Stress Response (ISR) signaling pathway because it contributes to synaptic plasticity – the brain’s ability to rewire circuits – as well as to learning and memory.

What they didn’t expect to see is that a population of cells called cholinergic interneurons, which comprise only 1 or 2 percent of the whole basal ganglia structure, seem to have the ISR pathway working all the time. The basal ganglia, which is the focus of much of Calakos’ work, plays a role in Parkinson’s and Huntington’s diseases, Tourette’s syndrome, obsessive compulsive disorder and more.

Nicole Calakos, the Lincoln Financial Group distinguished professor of Neurobiology and Neurology. (Alex Boerner)

“This totally changes how you think about the pathway,” Calakos said. “Everybody thought this pathway used an on-demand response type of mechanism, but what if some cells needed it for their everyday activities?”

To answer this, they blocked the ISR in just those rare interneurons in mice and it actually reproduced the enhanced performance on learned tasks that the earlier studies had shown when the pathway was blocked universally throughout the brain. This finding focuses attention on this select subset of brain cells, the cholinergic interneurons that release the chemical signal acetylcholine, as being responsible for at least some of the ‘superlearner’ behavior.

Since the integrated stress response pathway and its potential to enhance learning and memory was identified, drugs for dementia and traumatic brain injury are being designed to manipulate it and help the brain recover. But there may be more to the story than anyone realized, Calakos said.

“Our results show that the ISR plays a major role in acetylcholine-releasing cells, and our current best dementia drugs boost acetylcholine,” she said.

With their new tool, SPOTlight, the team were able to highlight the presence of cholinergic interneurons (red) which are only 1 to 2 percent of the cell population in the ganglia. (Helseth et al)

Acetylcholine, the chemical that these rare cholinergic interneurons use to signal in the brain, is well known for its powerful effects on influencing brain states for attention and learning. This finding suggests that at least some of the ‘superlearner’ properties of inhibiting the ISR occur by influencing brain state, rather than acting directly in the cells that are being rewired during learning.

In addition to the full research article, Science published on April 23 an article summary by Helseth and Calakos and a perspective piece by a pair of University of Minnesota neuroscientists highlighting the finding’s importance.

More work is required to sort out what ISR is and is not doing, but it’s possible that these new findings can help to develop “more precise, more nuanced Alzheimer’s drugs,” Calakos said.

Post by Karl Leif Bates

Duke Researcher Busts Metabolism Myths in New Book

Herman Pontzer explains where our calories really go, and what studying humanity’s past can teach us about staying healthy today.

Photo by Elena Georgiou, My City /EEA

Duke professor Herman Pontzer has spent his career counting calories. Not because he’s watching his waistline, exactly. But because, as he sees it, “in the economics of life, calories are the currency.” Every minute, everything the body does — growing, moving, fighting infection, even just existing — “all of it takes energy,” Pontzer says.

In his new book, “Burn,” the evolutionary anthropologist recounts the 10-plus years he and his colleagues have spent measuring the metabolisms of people ranging from ultra-athletes to office workers, as well as those of our closest animal relatives, and some of the surprising insights the research has revealed along the way.

Much of his work takes him to Tanzania, where members of the Hadza tribe still get their food the way our ancestors did — by hunting and gathering. By setting out on foot each day to hunt zebra and antelope or forage for berries and tubers, without guns or electricity or domesticated animals to lighten the load, the Hadza get more physical activity each day than most Westerners get in a week.

So they must burn more calories, right? Wrong.

Herman Pontzer
Herman Pontzer, associate professor of evolutionary anthropology at Duke

Pontzer and his colleagues have found that, despite their high activity levels, the Hadza don’t burn more energy per day than sedentary people in the U.S. and Europe.

These and other recent findings are changing the way we understand the links between energy expenditure, exercise and diet. For example, we’ve all been told that if we want to burn more calories and fight fat, we need to work out to boost our metabolism. But Pontzer says it’s not so simple.

“Our metabolic engines were not crafted by millions of years of evolution to guarantee a beach-ready bikini body,” Pontzer says. But rather, our metabolism has been primed “to pack on more fat than any other ape.” What’s more, our metabolism responds to changes in exercise and diet in ways that thwart our efforts to shed pounds.

What this means, Pontzer says, is you can walk 16,000 steps each day like the Hadza and you won’t lose weight. Sure, if you run a marathon tomorrow you’ll burn more energy than you did today. But over time, metabolism responds to changes in activity to keep the total energy you spend in check.

Pontzer’s book is more than a romp through the Krebs cycle. For anyone suffering pandemic-induced pangs of frustrated wanderlust, it’s also filled with adventure. He takes readers on an hours-long trek to watch a Hadza man track a wounded giraffe across the savannah, to the rainforests of Uganda to study climbing chimpanzees, and to the foothills of the Caucasus Mountains to unearth the 1.8 million-year-old remains of some of the first people who trekked out of Africa.

His humor shines through along the way. Even when awoken by a chorus of 300-pound lions just a few hundred yards from his tent, he stops to ponder whether his own stench gives him away, and what he might do if they come for his “soft American carcass, the  warm triple crème brie of human flesh.”

Pontzer spoke via email with Duke Today about his book:

Q: What’s the lesson the Hadza and other hunter-gatherers teach us about managing weight and staying healthy?

A: The Hadza stay incredibly fit and healthy throughout their lives, even into their older ages (60’s, 70’s, even 80’s). They don’t develop heart disease, diabetes, obesity, or the other diseases that we in the industrialized world are most likely to suffer from. They also have an incredibly active lifestyle, getting more physical activity in a typical day than most Americans get in a week.

My work with the Hadza showed that, surprisingly, even though they are so physically active, Hadza men and women burn the same number of calories each day as men and women in the U.S. and other industrialized countries. Instead of increasing the calories burned per day, the Hadza physical activity was changing the way they spend their calories — more on activity, less on other, unseen tasks in the body.

The takeaway for us here in the industrialized world is that we need to stay active to stay healthy, but we can’t count on exercise to increase our daily calorie burn. Our bodies adjust, keeping energy expenditure in a narrow range regardless of lifestyle. And that means that we need to focus on diet and the calories we consume in order to manage our weight. At the end of the day, our weight is a matter of calories eaten versus calories burned — and it’s really hard to change the calories we burn!

Q: You’re saying that exercise doesn’t matter? What’s the point, if we can’t eat that donut?

A: All those adjustments our bodies make responding to exercise are really important for our health! When we burn more calories on exercise, our bodies spend less energy on inflammation, stress reactivity (like cortisol), and other things that make us sick.

Q: What’s the biggest misunderstanding about human metabolism?

A: We’re told — through fitness magazines, diet fads, online calorie counters — that the energy we burn each day is under our control: if we exercise more, we’ll burn more calories and burn off fat. It’s not that simple! Your body is a clever, dynamic product of evolution, shifting and adapting to changes in our lifestyle.

Q: In your book you say we’re driven to magical thinking when it comes to calories. What do you mean by that?

A: Because our body is so clever and dynamic, and because humans are just bad at keeping track of what we eat, it’s awfully hard to keep track of the calories we consume and burn each day. That, along with the proliferation of fad diets and get-thin-quick schemes, has led to this idea that “calories don’t matter.” That’s magical thinking. Every ounce of your body — including every calorie of fat you carry — is food you consumed and didn’t burn off. If we want to lose weight, we must eat fewer calories than we burn. It really comes down to that.

Q: Some people say that if the cavemen didn’t eat it, we shouldn’t either. What does research show about what foods are “natural” for humans to eat?

A: There’s no singular, natural human diet. Hunter-gatherers like the Hadza eat a diverse mix of plant and animal foods that varies day to day, month to month, and year to year. There’s even more dietary diversity when we look across populations. Humans are built to thrive on a wide variety of diets — just about everything is on the menu.

That said, the ultra-processed foods we’re inundated with in our modern industrialized world really are unnatural. There are no Twinkies to forage in the wild. Those foods are literally engineered to be overconsumed, with a mix of flavors that overwhelm our brain’s ability to regulate our appetites. Now, it is still possible to lose weight on a Twinkie diet (I’m not recommending it!), if you’re very strict about the calories eaten per day. But we need to be really careful about how we incorporate ultra-processed foods into our daily diets, because they are calorie bombs that drive us to overconsume.

Q: If we could time travel, what would our hunter-gatherer ancestors make of our industrialized diet today?

A: We don’t even need to imagine — We are those hunter-gatherers! Biologically, genetically, we are the same species that we were a hundred thousand years ago, when hunting and gathering were the only game in town. When we’re confronted with modern ultra-processed foods, we struggle. They are engineered to be delicious, and we tend to overconsume.

Q: Has the COVID-19 pandemic brought any of these lessons home for you? What can we do to keep active and watch what we eat, even while working from home?

The pandemic has been a tragedy on so many levels — the loss of life, those suffering with long-term effects, the social and economic impacts. The impact on diet and exercise have been bad as well, for many of us. Stress eating is a real phenomenon, and the stress and emotional toll of the pandemic — along with having easy access to the snacks in our kitchen — have led many to gain weight. Physical activity seems to have declined for many. There aren’t easy answers, but we should try to make a point to get active every day. And we can help ourselves make better decisions about food by keeping ultra-processed foods out of our houses. You can’t plow through a bag of chips if you don’t have chips in your cupboard.

Q: You’ve measured the energy costs of activities ranging from taking a breath to doing an Ironman. What is one of the more extreme or surprising calorie-burning activities that you’ve measured, or would like to measure, in humans or some other animal?

A: With colleagues from Japan, I measured the energy cost of a heartbeat – a tricky bit of metabolic measurement! Turns out each beat of your heart burns about 1/300th of a kilocalorie! Amazing how efficient our bodies can be.

Q: What is something people have questions about that we just don’t know the answer to yet? What would it take to find out?

A: Right now we’re excited about measuring the adjustments our bodies make when we increase our exercise: how exactly does burning more energy on physical activity impact our immune system, our stress response, our reproductive system? It will take a long-term study of exercise to see how these systems change over time.

Robin Smith - University Communications
Robin Smith – University Communications

Pardon the Irruption: Winged Northern Visitors Massed for Tasty NC Mast

One morning in November, during a visit to my parents’ house in Richmond, Virginia, I woke up to a text from my mom. “Evening Grosbeaks at the river. Want to go?” Obviously I wanted to go. I’d heard that they had left their normal range, but I was shocked that they’d made it to Richmond—Evening Grosbeaks hadn’t come this far south in decades.

Evening Grosbeaks on a feeder in Hillsborough. The males are bright (lower right), the females more understated (upper left and right). A Purple Finch (center), another northern visitor, has joined them. (Lane Scher)

This winter has been a special treat for birdwatchers—a huge “irruption” year for many northern bird species, like the Evening Grosbeak. Many irruptive species are in the finch family, which includes siskins, redpolls, crossbills and some grosbeaks. These species usually spend their winters in the northern US and Canada, but every so often they’ll journey farther south. What causes these birds to make massive flights some years and not others? It’s simple—food.

Many birds eat seeds from trees, which scientists call “mast,” in winter. But mast is produced irregularly in cycles—lots of mast one year, and little the next. Birds with irruptive migratory patterns move around to find food in winter. During years of large mast production, irruptive birds can stay in their preferred range farther north. But when food is scarce, they fly south.

Mast is an important food source not only for these irruptive bird species, but also for local bird species and mammals. In fact, mast cycles impact the entire forest food web. Years of high seed production, sometimes called “bumper crops”, lead to larger rodent populations, which then eat the eggs of songbirds. Mast might also be tied to outbreaks of tick-borne diseases like Lyme disease: rodent populations grow in big mast years, which means there are more hosts for ticks, leading to more disease.

Mast cycles can have such massive impacts on animal populations because the seed production of each tree species is synchronized across large geographic areas. That means that in one year, trees of a particular species in one area will produce many seeds, but in a neighboring region the same species might produce few seeds. These patterns create a food landscape that is dynamic across both space and time.

Ecologists want to understand how mast cycles work—and Duke is home to the founder and headquarters of MASTIF, a global network with exactly this goal. Dr. Jim Clark of the Nicholas School of the Environment wants to understand how climate drives mast cycles, and how these cycles will change under climate change. The MASTIF network is a huge collaboration that now includes over 2.5 million data points, each representing the mast produced by one tree in one year.

The Evening Grosbeak map from
Peterson’s Field Guide to Eastern Birds shows that food-seeking irruptions can indeed reach Florida, as they have this year.

As a PhD student in Dr. Clark’s lab, I’m studying the relationship between mast cycles and the bird populations they support. I want to understand how birds respond to an environment that is constantly changing—in this case, how they respond to spatial and temporal changes in food availability. This historic irruption year is a perfect example of exactly this question: a year of low mast in the north has caused bird species to travel far outside their normal range to find food.

Interestingly, the association between these irruptive birds and food availability is so strong that it can be predicted fairly easily. The Winter Finch Forecast is based on a survey of mast crops across northern North America, which is then translated into a prediction of irruption patterns. The 2020 forecast noted that Evening Grosbeak populations would be larger this year due to outbreaks of spruce budworm, an important food source during the breeding season. This increase in the population size, combined with low winter food abundance, has led to a historic flight south.

The Clark Lab’s goal of understanding and predicting mast cycles would further our knowledge of these bird species’ unique migration patterns. With a more thorough understanding of mast patterns, we could better anticipate irruptions and implement informed conservation strategies. In addition to monitoring trees in long-term forest plots, the team uses data collected by citizen scientists through the MASTIF project on iNaturalist. With over 7,000 observations from 81 people across the world, these citizen scientists have contributed a huge amount of data.

I was thrilled to see the Evening Grosbeaks in November, and I assumed it would be my only chance. But since then, they’ve been seen throughout the Carolinas and into northern Florida. Recently, a homeowner in Hillsborough spotted a group of Evening Grosbeaks in his yard. He reported them to eBird, a citizen science project that collects data from birders around the world, and that birders use to locate rare species.

Since he reported them, birders have flocked to his yard in numbers almost as stunning as the birds themselves. Over the last few weeks, he’s counted up to 60 grosbeaks on a good day, and his yard has been visited by over 250 birders. Birders don’t want to miss this—no one knows when the next big irruption will be.

Guest post by Lane Scher, a Ph.D. student in Ecology at the Nicholas School of the Environment.

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