Picky eaters endure: Ecologists use DNA to explore diet breadth of wild herbivores

Utah State University researcher Sara Weinstein and multi-institution team pursue large-scale survey of small mammal food choices, and publish findings of eight-year, NSF-funded study in PNAS.

Utah State University

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A woodrat feasts on a berry. The small herbivores are known for eating just about any plant put in from of them, says Utah State University ecologist Sara Weinstein. Weinstein and colleagues published findings about a large-scale survey about the mammals’ dietary choices in the Sept. 15, 2025 issue of the Proceedings of the National Academy of Sciences.

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Credit: Sara Weinstein

LOGAN, UTAH, USA – It’s not easy eating green. Most plants are heavily defended with chemicals to deter plant eaters. For these herbivores, getting enough to eat, while minimizing exposure to toxins, is a persistent challenge that shapes their foraging choices.

Understanding how these animals navigate these choices is fundamental to understanding what these creatures need to survive and how species respond to changing conditions, says Utah State University ecologist Sara Weinstein.

Woodrats (genus Neotoma) provide an unexpected model for studying animal diets, she says. Native to North America, these herbivorous rodents consume a wide variety of plants.

“Woodrats are remarkable in their ability to eat truly awful, toxic plants,” says Weinstein, assistant professor in USU’s Department of Biology and Ecology Center. “If there are no other options, woodrats can consume plants like creosote bush, mesquite and juniper, which are full of disagreeable compounds like alkaloids and terpenes.”

Weinstein, along with University of Utah scientists Denise Dearing and Dylan Klure, USU adjunct faculty colleague Marc Mayes at Spatial Informatics Group-Natural Assets Laboratory in Pleasanton, California; and research partners at ARUP Laboratories in Salt Lake City, San Francisco State University and the North Carolina Museum of Natural Sciences, reports findings from a nearly eight-year, large-scale survey of woodrat populations throughout North America in the Sept. 15, 2025 issue of the Proceedings of the American Academy of Sciences.

The research was supported by the National Science Foundation.  

“Woodrats are a phenomenal model organism for understanding how wild animals make choices about what to eat,” says Weinstein, “They live in a landscape with varied food options, some better than others, and we can use this natural variation to understand how they decide what to consume.”

Unlike rats typically found in urban and suburban areas, woodrats shy away from humans.

“Woodrats are very distant cousins of the better known, and omnivorous, New York pizza rat,” she says. “You are unlikely to see woodrats, unless you’re in relatively undeveloped habitat.”

Yet the timid woodrats live throughout the United States and their large numbers make them excellent study subjects, Weinstein says.

“They’re everywhere, with multiple species often present in the same area, which gives us lots of replication to look at what determines diet breadth at the individual, population and species level,” she says.

Observing how woodrats choose foods at an individual level, as well as at the population level, Weinstein says, reveals how the animals are balancing the challenges of finding enough to eat without poisoning themselves.

The animals’ small size also makes them easy-to-manage research subjects.

“Compared to large herbivores like deer, moose or elephants, woodrats are much easier to capture and handle,” she says. “They also readily provide us with material for diet analyses, because they tend to defecate in traps.”

These droppings provide a treasure trove of information.

“Each sample combines about a day of food choices,” Weinstein says. “We can get a snapshot of everything the animal has eaten.’

Advancements with DNA metabarcoding, facilitated by next-generation sequencing over the past decade, have revolutionized our ability to analyze animal diets, she says. “It’s a very powerful and accessible technique to characterize the unseen.”

This information is critical for understanding species’ resilience, yet Weinstein says dietary niche breadth remains poorly understood in mammalian herbivores. Results from species, population and individual level surveys suggest that costs of both specialization and generalization dictate diet breadth.

“A longstanding notion is that if you’re highly specific in what you eat – you only eat one thing – then, if you lose access to that plant – say, it disappears because the ecosystem changes or an invasive species pushes it out – you’re going to be in trouble,” she says.

If you’re a generalist and able to pivot quickly to an alternative food source, your chances of survival improve.

“Most woodrat populations are generalists, but at the individual level, these generalists’ diets may not be as broad as we previously assumed,” Weinstein says. “We tend to think of generalists as being a jack-of-all-trades, master of none. However, it looks like most generalists are more aptly described as jacks-of-all trades, master of some.”

Individuals appear to select a consistent subset of plants, she says, which likely helps them to manage the costs and risks of consuming potentially poisonous food.

“Ultimately, these constraints on animal diets have important implications for our understanding of food webs, species interactions and which populations are more likely to persist in changing ecosystems,” Weinstein says.

 

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2413556122 

Method of Research

Data/statistical analysis

Subject of Research

Animals

Article Title

Large-scale surveys of woodrats (Neotoma spp.) reveal constraints on diet breadth in herbivorous mammals

Article Publication Date

15-Sep-2025

 

When the wireless data runs dry

Pitt Professor Wei Gao receives Best Paper Award for research to assess and improve the quality of synthetic wireless data

University of Pittsburgh

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To train artificial intelligence (AI) models, researchers need good data and lots of it. However, most real-world data has already been used, leading scientists to generate synthetic data. While the generated data helps solve the issue of quantity, it may not always have good quality, and assessing its quality has been overlooked.

Wei Gao, associate professor of electrical and computer engineering at the University of Pittsburgh Swanson School of Engineering, has collaborated with researchers from Peking University to develop analytical metrics to qualitatively evaluate the quality of synthetic wireless data. The researchers have created a novel framework that significantly improves the task-driven training of AI models using synthetic wireless data.

Their work is detailed in “Data Can Speak for Itself: Quality-Guided Utilization of Wireless Synthetic Data” (DOI: 10.48550/arXiv.2506.23174), which received the Best Paper Award in June at the MobiSys 2025 International Conference on Mobile Systems, Applications, and Services.

Assessing affinity and diversity

“Synthetic data is vital for training AI models, but for modalities such as images, video, or sound, and especially wireless signals, generating good data can be difficult,” said Gao, who also directs the Pitt Intelligent Systems Laboratory.

Gao has developed metrics to quantify affinity and diversity, essential qualities for synthetic data to be used for effectively training AI models.

“Generated data shouldn’t be random,” said Gao. “Take human faces. If you’re training an AI model to identify human faces, you need to ensure that the images of faces represent actual faces. They can’t have three eyes or two noses. They must have affinity.”

The images also need diversity. Training an AI model on a million images of an identical face won’t achieve much. While the faces must have affinity, they must also be different, as human faces are. As Gao noted, “AI models learn from variation.”

Different tasks have different requirements for judging affinity and diversity. Recognizing a specific human face is different than distinguishing it from that of a dog or a cat, with each task having unique data requirements. Therefore, in systemically assessing the quality of synthetic data, the team applied a task-specific approach.

“We applied our method to downstream tasks and evaluated the existing work of synthesizing data,” said Gao. “We found that most synthetic data achieved good diversity, but some had problems satisfying affinity, especially wireless signals.”

The challenge of synthetic wireless data

Today, wireless signals are used in technologies such as home and sleep monitoring, interactive gaming, and virtual reality. Cell phone and Wi-Fi signals, as radio waves, hit objects and bounce back toward their source. These signals can be interpreted to indicate everything from sleep patterns to the shape of a person sitting on a couch.

To advance this technology, researchers need more wireless data to train models to recognize human behaviors in the signal patterns. However, as a waveform, the signals are difficult for humans to evaluate.

It’s not like human faces, which can be clearly defined. “Our research found that current synthetic wireless data is limited in its affinity,” said Gao. “This leads to mislabeled data and degraded task performance.”

To improve affinity in wireless signals, the researchers took a semi-supervised learning approach. “We used a small amount of labeled synthetic data, which was verified as legitimate,” Gao said. “We used this data to teach the model what is and isn’t legitimate.”

Gao and his collaborators developed SynCheck, a framework that filters out synthetic wireless samples with low affinity and labels the remaining samples during iterative training of a model.

“We found that our system improves performance by 4.3% whereas a nonselective use of synthetic wireless data degrades performance by 13.4%,” Gao noted.

This research makes an important first step toward ensuring not just an endless stream of data, but of quality data that scientists can use to train more sophisticated AI models.

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DOI

10.48550/arXiv.2506.23174 

Method of Research

Computational simulation/modeling

 

Culture is driving a major shift in human evolution, new theory proposes

University of Maine

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Timothy W. Waring

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Credit: Photo courtesy of Timothy W. Waring

Researchers at the University of Maine are theorizing that human beings may be in the midst of a major evolutionary shift — driven not by genes, but by culture.

In a paper published in the Oxford journal BioScience, Timothy M. Waring, an associate professor of economics and sustainability, and Zachary T. Wood, a researcher in ecology and environmental sciences, argue that culture is overtaking genetics as the main force shaping human evolution. 

“Human evolution seems to be changing gears,” said Waring. “When we learn useful skills, institutions or technologies from each other, we are inheriting adaptive cultural practices. On reviewing the evidence, we find that culture solves problems much more rapidly than genetic evolution. This suggests our species is in the middle of a great evolutionary transition.”

Cultural practices — from farming methods to legal codes — spread and adapt far faster than genes can, allowing human groups to adapt to new environments and solve novel problems in ways biology alone could never match. According to the research team, this long-term evolutionary transition extends deep into the past, it is accelerating and may define our species for millenia to come. 

Culture now preempts genetic adaptation

“Cultural evolution eats genetic evolution for breakfast,” said Wood, “it’s not even close.”

Waring and Wood describe how in the modern environment cultural systems adapt so rapidly they routinely “preempt” genetic adaptation. For example, eyeglasses and surgery correct vision problems that genes once left to natural selection. Medical technologies like cesarean sections or fertility treatments allow people to survive and reproduce in circumstances that once would have been fatal or sterile. These cultural solutions, researchers argue, reduce the role of genetic adaptation and increase our reliance on cultural systems such as hospitals, schools and governments.

“Ask yourself this: what matters more for your personal life outcomes, the genes you are born with, or the country where you live?” Waring said. “Today, your well-being is determined less and less by your personal biology and more and more by the cultural systems that surround you — your community, your nation, your technologies. And the importance of culture tends to grow over the long term because culture accumulates adaptive solutions more rapidly.”

Over time, this dynamic could mean that human survival and reproduction depend less on individual genetic traits and more on the health of societies and their cultural infrastructure.

But, this transition comes with a twist. Because culture is fundamentally a shared phenomenon, culture tends to generate group-based solutions.

Culture is group thing

Using evidence from anthropology, biology and history, Waring and Wood argue that group-level cultural adaptation has been shaping human societies for millennia, from the spread of agriculture to the rise of modern states. They note that today, improvements in health, longevity and survival reliably come from group-level cultural systems like scientific medicine and hospitals, sanitation infrastructure and education systems rather than individual intelligence or genetic change.

The researchers argue that if humans are evolving to rely on cultural adaptation, we are also evolving to become more group-oriented and group-dependent, signaling a change in what it means to be human. 

A deeper transition

In the history of evolution, life sometimes undergoes transitions which change what it means to be an individual. This happened when single cells evolved to become multicellular organisms and social insects evolved into ultra-cooperative colonies. These individuality transitions transform how life is organized, adapts and reproduces. Biologists have been skeptical that such a transition is occurring in humans. 

But Waring and Wood suggest that because culture is fundamentally shared, our shift to cultural adaptation also means a fundamental reorganization of human individuality — toward the group.

“Cultural organization makes groups more cooperative and effective. And larger, more capable groups adapt — via cultural change — more rapidly,” said Waring. “It’s a mutually reinforcing system, and the data suggest it is accelerating.”

For example, genetic engineering is a form of cultural control of genetic material, but genetic engineering requires a large complex society. So, in the far future, if the hypothesized transition ever comes to completion, our descendants may no longer be genetically evolving individuals, but societal “superorganisms” that evolve primarily via cultural change.

Future research

The researchers emphasize that their theory is testable and lay out a system for measuring how fast the transition is happening. The team is also developing mathematical and computer models of the process and plans to initiate a long-term data collection project in the near future. They caution, however, against treating cultural evolution as progress or inevitability. 

“We are not suggesting that some societies, like those with more wealth or better technology, are morally ‘better’ than others,” Wood said. “Evolution can create both good solutions and brutal outcomes. We believe this might help our whole species avoid the most brutal parts.”

The study is part of a growing body of research from Waring and his team at the Applied Cultural Evolution Laboratory at the University of Maine. Their goal is to use their understanding of deep patterns in human evolution to foster positive social change.

Still, the new research raises profound questions about humanity’s future. “If cultural inheritance continues to dominate, our fates as individuals, and the future of our species, may increasingly hinge on the strength and adaptability of our societies,” Waring said. And if so, the next stage of human evolution may not be written in DNA, but in the shared stories, systems, and institutions we create together.

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Journal

BioScience

DOI

10.1093/biosci/biaf094 

Article Title

Cultural inheritance is driving a transition in human evolution

Article Publication Date

15-Sep-2025

 

Study suggests most Americans would be healthier without daylight saving time

Permanent standard time may improve health

Stanford Medicine

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Every spring, Americans dutifully adjust their clocks forward to daylight saving time, and every fall, back to standard time — but no one seems very happy about it. The biannual time shift is not only inconvenient, it’s also known to be acutely bad for our health. The collective loss of an hour of sleep on the second Sunday in March has been linked to more heart attacks and fatal traffic accidents in the ensuing days.

Now, a study by Stanford Medicine researchers finds there are longer-term hazards as well — and better alternatives.

The researchers compared how three different time policies — permanent standard time, permanent daylight saving time and biannual shifting — could affect people’s circadian rhythms, and, in turn, their health throughout the country. Circadian rhythm is the body’s innate, roughly 24-hour clock, which regulates many physiological processes.

The team found that, from a circadian perspective, we’ve made the worst choice. Either permanent standard time or permanent daylight saving time would be healthier than our seasonal waffling, with permanent standard time benefitting the most people.

Indeed, by modeling light exposure, circadian impacts and health characteristics county by county, the researchers estimate that permanent standard time would prevent some 300,000 cases of stroke per year and result in 2.6 million fewer people having obesity. Permanent daylight saving time would achieve about two-thirds of the same effect.

“We found that staying in standard time or staying in daylight saving time is definitely better than switching twice a year,” said Jamie Zeitzer, PhD, professor of psychiatry and behavioral sciences and senior author of the study to publish Sept. 15 in the Proceedings of the National Academy of Sciences. The lead author is Lara Weed, a graduate student in bioengineering.

A theory lacking data

Even among people who want to end seasonal time shifts, there’s disagreement over which time policy to adopt.

“You have people who are passionate on both sides of this, and they have very different arguments,” Zeitzer said.

Supporters of permanent daylight saving time say more evening light could save energy, deter crime and give people more leisure time after work. Golf courses and open-air malls are big proponents, Zeitzer said. A trial of permanent daylight saving time begun in 1974, however, was so unpopular it was abandoned after less than a year. Among the objectors were parents worried about their children going to school in the dark.

Nevertheless, the duration of daylight saving time was later increased from six months to seven months. And since 2018, a bill proposing permanent daylight saving time has been introduced in Congress nearly every year, though it has never passed.

In the other camp, proponents of permanent standard time contend that more morning light is optimal for health. Organizations such as the American Academy of Sleep Medicine, the National Sleep Foundation and the American Medical Association have endorsed year-round standard time.

“It’s based on the theory that early morning light is better for our overall health,” Zeitzer said of these endorsements. “The problem is that it’s a theory without any data. And finally, we have data.”

Syncing to 24 hours

The human circadian cycle is not exactly 24 hours — for most people, it’s about 12 minutes longer — but it can be modulated by light. 

“When you get light in the morning, it speeds up the circadian cycle. When you get light in the evening, it slows things down,” Zeitzer said. “You generally need more morning light and less evening light to keep well synchronized to a 24-hour day.”

An out-of-sync circadian cycle has been associated with a range of poor health outcomes.

“The more light exposure you get at the wrong times, the weaker the circadian clock. All of these things that are downstream — for example, your immune system, your energy — don’t match up quite as well,” Zeitzer said.

The researchers used a mathematical model to translate light exposure under each time policy, based on local sunrise and sunset times, to circadian burden — essentially, how much a person’s innate clock has to shift to keep up with the 24-hour day. 

They found that over a year, most people would experience the least circadian burden under permanent standard time, which prioritizes morning light. The benefits vary somewhat by a person’s location within a time zone and their chronotype — whether they prefer early mornings, late nights or something in between.

Counterintuitively, people who are morning larks, who make up about 15% of the population and tend to have circadian cycles shorter than 24 hours, would experience the least circadian burden under permanent daylight savings time, as more evening light would extend their circadian cycles closer to 24 hours.

Health implications

To link circadian burden to specific health outcomes, the researchers analyzed county-level data from the Centers for Disease Control and Prevention on the prevalence of arthritis, cancer, chronic obstructive pulmonary disease, coronary heart disease, depression, diabetes, obesity and stroke.

Their models show that permanent standard time would lower the nationwide prevalence of obesity by 0.78% and the prevalence of stroke by 0.09%, conditions influenced by circadian health. These seemingly small percentage changes in common conditions would amount to 2.6 million fewer people with obesity and 300,000 fewer cases of stroke. Under permanent daylight time, the nationwide prevalence of obesity would decrease by 0.51%, or 1.7 million people, and stroke by 0.04%, or 220,000 cases. 

As expected, the models predicted no significant difference in conditions such as arthritis that have no direct link to circadian rhythms.

Not the last word

The study might be the most evidence-based analysis of the long-term health implications of different time policies, but it’s far from the last word, Zeitzer said.

For one thing, the researchers didn’t account for many factors that could influence real-life light exposure, including weather, geography and human behavior. 

In their calculations, the researchers assumed consistent and relatively circadian-friendly light habits, including a 10 p.m. to 7 a.m. sleep schedule, sunlight exposure before and after work and on weekends, and indoor light exposure from 9 a.m. to 5 p.m. and after sunset. But in reality, many people have erratic sleep schedules and spend more time indoors. 

“People’s light habits are probably much worse than what we assume in the models,” Zeitzer said. “Even in California, where the weather is great, people spend less than 5% of their day outside.”

Moreover, though circadian health seems to favor permanent standard time, the results are not conclusive enough to overshadow other considerations. Zeitzer hopes the study will encourage similar evidence-based analyses from other fields, such as economics and sociology.  

He also points out that time policy is simply choosing which clock hours represent sunrise and sunset, not altering the total amount of light there is. No policy will add light to the dark winter months.

“That’s the sun and the position of Earth,” he said. “We can’t do anything about that.”

The study received funding from the National Institutes of Health (grant F31HL170715).

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About Stanford Medicine

Stanford Medicine is an integrated academic health system comprising the Stanford School of Medicine and adult and pediatric health care delivery systems. Together, they harness the full potential of biomedicine through collaborative research, education and clinical care for patients. For more information, please visit med.stanford.edu.

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Journal

Proceedings of the National Academy of Sciences

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Circadian-Informed Modeling Predicts Regional Variation in Obesity and Stroke Outcomes Under Different Permanent U.S. Time Policies

Article Publication Date

15-Sep-2025

 

Association of exposure to primary aromatic amines with health risks in China

KeAi Communications Co., Ltd.

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URINARY CONCENTRATIONS OF PRIMARY AROMATIC AMINES ACROSS CHINA.

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Credit: Yao, Y., et al

Primary aromatic amines (PAAs) are a group of chemicals widely used in industrial processes, including the production of rubber, foams, dyes, plastics, and food packaging. Although some PAAs are known carcinogens, data on PAA exposure among the Chinese general population are scarce.

To that end, in a study published in the KeAi journal Environmental Chemistry and Ecotoxicology, a group of researchers from China reported a nationwide biomonitoring study they have conducted. It is the first comprehensive assessment of human exposure to primary aromatic amines (PAAs) across multiple cities in China, providing critical insights into potential health risks associated with PAA exposure.

In the study, the team of researchers analyzed 457 urine samples collected from residents across 16 cities in China, using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

“We detected 25 PAAs with aniline (ANI), meta-toluidine(m-TD), ortho-toluidine (o-TD), para-toluidine (p-TD), 4-ethoxyaniline (4-EA), and 3,4-diaminoanisole (3,4-DAAS) that are most frequently found,” shares corresponding author  Tao Zhang. “The sum median concentrations of all PAAs ranged from 0.93 to 3.8 ng/mL across the cities.”

Notably, urinary PAA levels significantly varied depending on demographic, geographic, and socioeconomic factors, with higher concentrations observed among smokers, non-adults, and residents from industrialized or ethnically distinct cities.

“The urinary concentrations of ΣPAAs were also significantly correlated with gross domestic product (GDP) and GDP per capita of select Chinese cities,” adds Zhang.

One surprising finding was that although the overall exposure levels for all PAAs appearing low, with hazard quotients remaining below 1, several compounds including 4-EA, m-TD, o-TD and p-TD, showed significant associations with the oxidative DNA damage biomarker 8-OHdG.

“These associations were most evident among non-smokers, suggesting that chronic low-level exposure may still trigger oxidative stress and elevate long-term cancer risks in the general population,” says Zhang. “While our results indicate that the current exposure levels are not immediately alarming, the positive correlations with oxidative stress marker 8-OHdG cannot be ignored.

First author Yanan Yao adds, “Our work provides the first baseline data of PAA exposure for the Chinese general population and highlights that even low concentrations may contribute to DNA damage over time. This points the need to strengthen monitoring and implement targeted public health interventions, particularly for vulnerable groups such as non-adults and non-smokers.”

In sum, this study not only fills a critical knowledge gap but also lays the groundwork for future environmental health policies in China. By highlighting subtle but measurable biological effects, it offers new perspectives on the importance of routine biomonitoring and the potential risks of everyday chemical exposure.

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Contact the author: Tao Zhang, Professor, School of Agriculture and Biotechnology, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China, zhangt47@mail.sysu.edu.cn

The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).

 

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Journal

Environmental Chemistry and Ecotoxicology

DOI

10.1016/j.enceco.2025.07.007 

Article Title

Exposure to carcinogenic primary aromatic amines and associated health risks among the Chinese general population: A nationwide biomonitoring study

COI Statement

Kurunthachalam Kannan served as the editor-in-chief, Tao Zhang as the associate editor, and Jingchuan Xue as a member of editorial board of Environmental Chemistry and Ecotoxicology. None of them were involved in the editorial review or the decision to publish this article. All authors declare that there have no competing interests.