Electric bandage holds promise for treating chronic wounds

North Carolina State University

 

image: 

Photo of a water-powered, electronics-free dressing (WPED) for electrical stimulation of wounds.

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Credit: Rajaram Kaveti

Researchers have developed an inexpensive bandage that uses an electric field to promote healing in chronic wounds. In animal testing, wounds that were treated with these electric bandages healed 30% faster than wounds treated with conventional bandages.

Chronic wounds are open wounds that heal slowly, if they heal at all. For example, sores that occur in some patients with diabetes are chronic wounds. These wounds are particularly problematic because they often recur after treatment and significantly increase the risk of amputation and death.

One of the challenges associated with chronic wounds is that existing treatment options are extremely expensive, which can create additional problems for patients.

“Our goal here was to develop a far less expensive technology that accelerates healing in patients with chronic wounds,” says Amay Bandodkar, co-corresponding author of the work and an assistant professor of electrical and computer engineering at North Carolina State University. “We also wanted to make sure that the technology is easy enough for people to use at home, rather than something that patients can only receive in clinical settings.”

“This project is part of a bigger DARPA project to accelerate wound healing with personalized wound dressings,” says Sam Sia, co-corresponding author of the work and professor of biomedical engineering at Columbia University. “This collaborative project shows that these lightweight bandages, which can provide electrical stimulation simply by adding water, healed wounds faster than the control, at a similar rate as bulkier and more expensive wound treatment.” 

Specifically, the research team developed water-powered, electronics-free dressings (WPEDs), which are disposable wound dressings that have electrodes on one side and a small, biocompatible battery on the other. The dressing is applied to a patient so that the electrodes come into contact with the wound. A drop of water is then applied to the battery, activating it. Once activated, the bandage produces an electric field for several hours.

“That electric field is critical, because it’s well established that electric fields accelerate healing in chronic wounds,” says Rajaram Kaveti, co-first author of the study and a post-doctoral researcher at NC State.

 

The electrodes are designed in a way that allows them to bend with the bandage and conform to the surface of the chronic wounds, which are often deep and irregularly shaped.

“This ability to conform is critical, because we want the electric field to be directed from the periphery of the wound toward the wound’s center,” says Kaveti. “In order to focus the electric field effectively, you want electrodes to be in contact with the patient at both the periphery and center of the wound itself. And since these wounds can be asymmetrical and deep, you need to have electrodes that can conform to a wide variety of surface features.”

“We tested the wound dressings in diabetic mice, which are a commonly used model for human wound healing,” says Maggie Jakus, co-first author of the study and a graduate student at Columbia. “We found that the electrical stimulation from the device sped up the rate of wound closure, promoted new blood vessel formation, and reduced inflammation, all of which point to overall improved wound healing.” 

Specifically, the researchers found that mice who received treatment with WPEDs healed about 30% faster than mice who received conventional bandages.

“But it is equally important that these bandages can be produced at relatively low cost – we’re talking about a couple of dollars per dressing in overhead costs.” says Bandodkar.

“Diabetic foot ulceration is a serious problem that can lead to lower extremity amputations,” says Aristidis Veves, a co-author of the study and professor of surgery at Beth Israel Deaconess Center. “There is urgent need for new therapeutic approaches, as the last one that was approved by the Food and Drug Administration was developed more than 25 years ago. My team is very lucky to participate in this project that investigates innovative and efficient new techniques that have the potential to revolutionize the management of diabetic foot ulcers.”

In addition, the WPEDs can be applied quickly and easily. And once applied, patients can move around and take part in daily activities. This functionality means that patients can receive treatment at home and are more likely to comply with treatment. In other words, patients are less likely to skip treatment sessions or take shortcuts, since they aren’t required to come to a clinic or remain immobile for hours.

“Next steps for us include additional work to fine-tune our ability to reduce fluctuations in the electric field and extend the duration of the field. We are also moving forward with additional testing that will get us closer to clinical trials and – ultimately – practical use that can help people,” says Bandodkar. 

The paper, “Water-powered, electronics-free dressings that electrically stimulate wounds for rapid wound closure,” will be published Aug. 7 in the open-access journal Science Advances. The paper’s co-authors include Henry Chen, an undergraduate in the joint biomedical engineering department at NC State and UNC; Bhavya Jain, Navya Mishra, Nivesh Sharma and Baha Erim Uzunoğlu, Ph.D. students at NC State; Darragh Kennedy and Elizabeth Caso of Columbia; Georgios Theocharidis and Brandon Sumpio of Beth Israel Deaconess Medical Center; Won Bae Han of Korea University and the Georgia Institute of Technology; Tae-Min Jang of Korea University; and Suk-Won Hwang of Korea University and the Korea Institute of Science and Technology.

This work was done with support from the Defense Advanced Research Projects Agency under grant D20AC00004 and from the Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies at NC State, which is funded by National Science Foundation grant 1160483. Bandodkar and Kaveti are inventors on a patent application related to this work.

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Journal

Science Advances

DOI

10.1126/sciadv.ado7538 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Water-powered, electronics-free dressings that electrically stimulate wounds for rapid wound closure

Article Publication Date

7-Aug-2024

COI Statement

Bandodkar and Kaveti are inventors on a patent application related to this work.

 

Humans change their own behavior when training AI

McKelvey’s Chien-Ju Ho working with Art & Sciences’ Wouter Kool, PhD student Lauren Treiman to understand how human behavior changes in training AI

Washington University in St. Louis

By Chris Woolston

A new cross-disciplinary study by WashU researchers has uncovered an unexpected psychological phenomenon at the intersection of human behavior and artificial intelligence: When told they were training AI to play a bargaining game, participants actively adjusted their own behavior to appear more fair and just, an impulse with potentially important implications for real-world AI developers.

“The participants seemed to have a motivation to train AI for fairness, which is encouraging, but other people might have different agendas,” said Lauren Treiman, a PhD student in the Division of Computational and Data Sciences and lead author of the study. “Developers should know that people will intentionally change their behavior when they know it will be used to train AI.”

The study, published in PNAS, was supported by a seed grant from the Transdisciplinary Institute in Applied Data Sciences (TRIADS), a signature initiative of the Arts & Sciences Strategic Plan. The co-authors are Wouter Kool, assistant professor of psychological and brain sciences in Arts & Sciences, and Chien-Ju Ho, assistant professor of computer science and engineering in the McKelvey School of Engineering. Kool and Ho are Treiman’s graduate advisors.

The study included five experiments, each with roughly 200-300 participants. Subjects were asked to play the “Ultimatum Game,” a challenge that requires them to negotiate small cash payouts (just $1 to $6) with other human players or a computer. In some cases, they were told their decisions would be used to teach an AI bot how to play the game.

The players who thought they were training AI were consistently more likely to seek a fair share of the payout, even if such fairness cost them a few bucks. Interestingly, that behavior change persisted even after they were told their decisions were no longer being used to train AI, suggesting the experience of shaping technology had a lasting impact on decision-making.  “As cognitive scientists, we’re interested in habit formation,” Kool said. “This is a cool example because the behavior continued even when it was not called for anymore.”

Still, the impulse behind the behavior isn’t entirely clear. Researchers didn’t ask about specific motivations and strategies, and Kool explained that participants may not have felt a strong obligation to make AI more ethical. It’s possible, he said, that the experiment simply brought out their natural tendencies to reject offers that seemed unfair. “They may not really be thinking about the future consequences,” he said. “They could just be taking the easy way out.” 

“The study underscores the important human element in the training of AI,” said Ho, a computer scientist who studies the relationships between human behaviors and machine learning algorithms. “A lot of AI training is based on human decisions,” he said. “If human biases during AI training aren’t taken into account, the resulting AI will also be biased. In the last few years, we’ve seen a lot of issues arising from this sort of mismatch between AI training and deployment.”

Some facial recognition software, for example, is less accurate at identifying people of color, Ho said. “That’s partly because the data used to train AI is biased and unrepresentative,” he said.

Treiman is now conducting follow-up experiments to get a better sense of the motivations and strategies of people training AI. “It’s very important to consider the psychological aspects of computer science,” she said. 

Treiman LS, Ho CJ, Kool W. The consequences of AI training on human decision-making. Proceedings of the National Academy of Sciences (PNAS) Aug. 6, 2024.DOI: https://doi.org/10.1073/pnas.2408731121

 

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Journal

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2408731121 

 

Asthma emergencies spike when allergenic pollen blooms

New study highlights need for science-based pollen forecasts

Peer-Reviewed Publication

Cornell University

ITHACA, N.Y. – A new Cornell University study that tracks how many asthma-related emergency room visits result from pollen in metropolitan areas highlights the importance of knowing local plants and the need for developing science-based pollen forecasts.

Such forecasts could alert vulnerable individuals on days when they should consider staying indoors or taking allergy medications ahead of time.

“Even though the percent of asthma-related emergency department visits associated with pollen overall was only a few percent on an annual basis, at certain times of year when particular types of pollen were spiking, we sometimes saw up to almost 20% of visits were due to pollen,” said Daniel Katz, assistant professor and first author of the study.

To figure out which asthma emergencies may have been activated by pollen, as opposed to a virus or other cause, the researchers collected data from the Texas Department of State Health Services and analyzed close to 175,000 asthma-related emergency room visits between 2015 and 2020. They singled out visits from patients who lived within about 15 miles of one of eight pollen monitoring stations where airborne pollen concentrations are measured.

When pollen and virus prevalence were high at the same time, the researchers had the advantage of an abundance of data, from eight cities and over five years, to uncover the likely causes.

“Sometimes the timing of when viruses were prevalent changed,” Katz said, “and sometimes the timing of when pollen was in the air changed. So, because of this natural variability, we were able to better untangle what was contributing to these asthma-related emergency department visits.”

The researchers chose cities for the study based on their proximity to Central Texas, where a species of tree, Ashe juniper (Juniperus ashei), one of the most important allergenic pollen-producing trees, is prevalent. Some cities were in the middle of these pollen hot spots and others were far from them.

“We ended up finding that some of the cities had these spikes in asthma-related emergency department visits in January, when that species releases its pollen, whereas cities outside its primary range did not have corresponding spikes,” Katz said. Still, he said, various pollen is in the air for most of the year in Texas, creating challenges for people with asthma.

The study helps inform Katz’s ongoing work to develop publicly available pollen forecasts that incorporate remote sensing and atmospheric dispersion and plant ecology.

For additional information, read this Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

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Journal

Environmental Research

DOI

10.1016/j.envres.2024.119346 

 

New Center of Excellence at Chapman University will study quantum theory and the nature of reality

Chapman University

An interdisciplinary team of scholars have received a $2.43 million dollar grant from the John Templeton Foundation to create a “Southern California Quantum Foundations Hub” at Chapman University. This unique collaboration includes theoretical physicists, experimental physicists and philosophers, who will apply the methods of their respective disciplines to provide deeper insights into the nature of reality that quantum theory is silent about. The Templeton Foundation has identified the area of quantum foundations as one of their key funding priorities.

Researchers Andrew Jordan (physics), Matt Leifer (physics), Emily Adlam (philosophy and physics), and Kelvin McQueen (philosophy) at Chapman will seek answers to some of the most pressing and confounding questions in their fields. Three research themes will be explored: (1) The Nature of the Quantum State, (2) Past and Future Boundary Conditions, and (3) Agency in Quantum Observers. Each theme has contributions planned for theory, experiment, and philosophy. The grant will also support experiments by Aephraim Steinberg (University of Toronto, physics) and Eddy Chen (UCSD, philosophy).

Andrew Jordan, professor, Schmid College of Science and Technology said, “Chapman university has invested strongly to make one of the best quantum foundations groups in the world. I’m very excited by the John Templeton foundation’s decision to choose our faculty to lead their research hub on this topic in the United States. Our activities will provide a center to attract experts from around the world to come and work with us.”

“We plan to work on topics that will expand our understanding of the quantum state and in what sense it is reflective of external reality and/or our degree of knowledge. The nature of time is also fundamental to integrating past and future events into a new theory we are developing of continuously monitored quantum systems.  We will also explore our freedom as agents acting on quantum systems and explore the idea of if an agent itself can be a quantum system.”

Topics in quantum foundations, as well as breaking discoveries and insights will also be taught to the wider scientific community and public through regular seminars posted on their YouTube channel, annual conferences, and public lectures. 

“The John Templeton Foundation grant establishing the Southern California Quantum Foundations Hub at Chapman University is a testament to the game-changing impact of our faculty’s interdisciplinary research–past and future,” said Chapman President Daniele Struppa, Ph.D. “With this grant, our university will become the primary center of excellence in the United States for the field of quantum foundations, an emerging field ripe with potential for major scientific discoveries and a greater understanding of the nature of reality.”

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About Chapman University

Founded in 1861, Chapman University is a nationally ranked private university in Orange, California, about 30 miles south of Los Angeles. Chapman serves nearly 10,000 undergraduate and graduate students, with a 12:1 student-to-faculty ratio. Students can choose from 123 areas of study within 11 colleges for a personalized education. Chapman is categorized by the Carnegie Classification as an R2 "high research activity" institution. Students at Chapman learn directly from distinguished world-class faculty including Nobel Prize winners, MacArthur fellows, published authors and Academy Award winners. The campus has produced a Rhodes Scholar, been named a top producer of Fulbright Scholars and hosts a chapter of Phi Beta Kappa, the nation's oldest and most prestigious honor society. Chapman also includes the Harry and Diane Rinker Health Science Campus in Irvine. The university features the No. 4 film school and No. 60 business school in the U.S. Learn more about Chapman University: www.chapman.edu.

 

 

A vaping cessation text message program for adolescent e-cigarette users

JAMA Network

About The Study: A tailored, interactive text message intervention increased self-reported vaping cessation rates among adolescents recruited via social media channels.

Quote from corresponding author Amanda L. Graham, PhD:

“Health care providers, teachers, and parents have been asking how to help teens quit vaping. This study is a critical breakthrough that demonstrates the power of a behavioral intervention for vaping cessation. Text messages serve as powerful reminders of an initial commitment to quit and can deliver proven behavior change support right to a young person’s phone.

“We also did not see evidence that teens who quit vaping transitioned to smoking. The intervention was effective in reducing dual use (smoking and vaping) and keeping teens in this study from starting to smoke.”

Contact information for Amanda L. Graham, PhD: email Megan Kelley (mkelley@truthinitiative.org).

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ 

(doi:10.1001/jama.2024.11057)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time https://jamanetwork.com/journals/jama/fullarticle/10.1001/jama.2024.11057?guestAccessKey=52355ac8-73a4-4e2b-b400-3cf946de795c&utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=080724

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Journal

JAMA

Some e-cigarette chemicals mimic nicotine, possibly bypassing regulation

Products also use flavors and sweeteners like those preferred by people who are younger or using e-cigarettes for the first time, raising concerns about unknown health risks

Duke University Medical Center

DURHAM, N.C. – In what appears to be an effort to bypass public health regulations covering vaping products, some tobacco companies have begun replacing nicotine in e-cigarettes with related chemicals that have similar properties but unknown health effects, Duke Health researchers report.

In a research letter appearing Aug. 7 in JAMA, study authors at Duke and Yale University also found that the quantity of these chemicals, known as nicotine analogs, are not accurately disclosed on the packaging.

“Vaping products containing nicotine are subject to federal laws that prohibit sales to people  under the age of 21,” said study co-author Sairam V. Jabba, D.V.M., Ph.D., a senior research scientist at Duke University School of Medicine.

“Nicotine analogs are currently not subject to the FDA process and have not been studied for their health effects,” Jabba said. "Our analysis of some of these analog-containing vaping products sold in the U.S. found significant and concerning inaccuracies in the ingredients these products claim to contain and what they actually contain. Further, it’s possible manufacturers are attempting to avoid FDA tobacco regulation.”

One chemical, known as 6-methyl nicotine, has been shown in rodent experiments to be far more potent than nicotine in targeting the brain’s nicotine receptors and more toxic than nicotine. Another, called nicotinamide, is marketed as targeting the same brain receptors as nicotine, despite evidence it does not bind to these receptors.

The nicotine analogs were included in flavored e-cigarettes, which prior research has indicated are preferred by youths and those who vape for the first time.

Jabba and colleagues, including co-senior author Sven Eric Jordt, Ph.D., analyzed an e-cigarette product sold under the brand name Spree Bar, which comes in at least nine flavors and is listed as containing 5 percent 6-methyl nicotine. Study results showed the actual amount of the chemical was about 88% less than labeled. The e-cigarettes also included an artificial sweetener that is up to 13,000 times sweeter than table sugar, and an artificial coolant that mimics menthol’s effects.

A second brand of e-cigarettes -- marketed as Nixotine, Nixodine, Nixamide and Nic-Safe – contained a nicotine analog called nicotinamide, also at levels lower than the labels indicated, and combined with undisclosed amounts of 6-methyl nicotine. This brand did not include sweeteners or coolants.

“These products appear to be designed to circumvent the laws and regulations in place to protect people -- especially children -- from the harmful effects of smoking and tobacco use,” Jordt said. “We do not know what these chemicals do when they are heated and inhaled. These are questions that should be answered before we allow products on the market.”

In addition to Jordt and Jabba, study authors include Hanno C. Erythropel, Peter Silinski, Paul T. Anastas, Suchitra Krishnan-Sarin and Julie B. Zimmerman.

Yale’s Tobacco Center of Regulatory Science received funding support for the study from the National Institute on Drug Abuse, which is part of the National Institutes of Health (U54DA036151), and the Center for Tobacco Products of the FDA. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH or the FDA.

 

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Journal

JAMA

 

Neighborhood socioeconomic disadvantage across the life course and premature mortality

JAMA Network

About The Study: 

Low neighborhood socioeconomic status was associated with premature mortality in this study. The risk of premature mortality was greatest among individuals experiencing persistently low neighborhood socioeconomic status from young to middle adulthood. Place-based interventions that target neighborhood social determinants of health should be designed from a life course perspective that accounts for early-life socioeconomic inequality. 

Corresponding Author: To contact the corresponding author, Wayne R. Lawrence, DrPH, email wayne.lawrence@nih.gov.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2024.26243)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

#  #  #

Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time http://jamanetwork.com/journals/jamanetworkopen/fullarticle/10.1001/jamanetworkopen.2024.26243?utm_source=For_The_Media&utm_medium=referral&utm_campaign=ftm_links&utm_term=080724

About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication. 

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Journal

JAMA Network Open

 

Cocaine discovery could pave way for treatment for substance abuse

University of Copenhagen - The Faculty of Health and Medical Sciences

You have probably heard of dopamine. The substance also known as the “feel-good hormone”.

Drugs such as cocaine cause a surge of dopamine in the brain. Normally, a protein in the brain called the dopamine transporter (DAT) helps regulate dopamine levels and prevent the brain from thinking that every experience is pleasurable.

However, when affected by cocaine, the brain is unable to regulate dopamine levels. Previously, researchers did not know how cocaine affects the different transporters in the brain, but a new study from the University of Copenhagen has changed that.

“We have learned how cocaine binds to the dopamine transporter, which is a protein responsible for regulating dopamine levels in the brain. What we did was describe the structure of the dopamine transporter, which gave us molecular-level insight into how it is inhibited by cocaine,” says PhD Student Jeppe Cederholm Nielsen, who is one of the researchers responsible for the new study.

Our dream is to find a medical treatment for cocaine abuse.

Professor Claus Løland

When the brain is unable to regulate dopamine levels, everything we do seems great, the researchers explain. Cocaine does not make the brain release more dopamine, but it prevents it from regulating and removing dopamine.

“When we experience something as pleasurable, it is because the dopamine that is released in the brain stimulates the reward centre. The role of the dopamine transporter is to stop this process by removing dopamine,” says Professor Claus Løland from the Department of Neuroscience at the University of Copenhagen and adds:

“When cocaine blocks the dopamine transporter, dopamine will continue to stimulate the reward centre – even though the experience itself is not particularly pleasurable. In other words, we become incapable of distinguishing between what is truly pleasurable and what is not, and then all types of input given by our senses will seem great. You could say that cocaine tricks the brain. It is a form of chemical brainwashing.”

World’s most powerful microscope provides answers

To understand what cocaine does to the brain, the researchers studied the dopamine transporter, which is a very small protein – too small to be studied in a standard microscope.

“We have used the most powerful microscope in the world to study the structure of the atoms of the dopamine transporter. We have learned how cocaine binds and thus blocks this function, and this is important if we want to be able to stop cocaine from affecting the brain,” says Jeppe Cederholm Nielsen and adds:

“These proteins are so tiny that they are invisible under a microscope – even this extremely powerful microscope. But we used a couple of tricks to work around this and make them visible.”

Want to develop treatment for substance abuse

There is currently no for cocaine abuse, but in the long run the researchers want to that can help people get rid of their addictions.

“Our dream is to find a medical treatment for cocaine abuse. While fewer and fewer people are addicted to drugs in general, an increasing number of people become addicted to cocaine. It is one of the most addictive substances out there, and it is becoming more and more affordable,” says Claus Løland.

The researchers hope their new knowledge of the function of the dopamine transporter will help them understand addiction in general.

“Perhaps we will be able to treat addiction to a number of things, not just cocaine. For instance, addiction to gambling or other substances, which is also caused by a release of dopamine into the brain,” says Claus Løland and adds:

“If we were able to design a drug for addiction in general, we would be able to help a lot of people.”

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Journal

Nature

DOI

10.1038/s41586-024-07804-3 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Structure of the human dopamine transporter in complex with cocaine

Article Publication Date

7-Aug-2024

 

Plants offer fruit to insects to disperse dust-like seeds

Kobe University

 

image: 

The shrub-like plant Rhynchotechum discolor produces fruit that are difficult to see from above but suitable for ground-dwelling insects. However, seed dispersal by insects was previously thought to be limited to cases where other dispersers were not available or where fungi-eating plants already had dust-like seeds. The Kobe University botanist SUETSUGU Kenji says, “Our findings challenge the notion that insect-mediated seed dispersal is a special case and suggest that it may be more widespread and ecologically important than previously understood.”

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Credit: ANSAI Shun

Fruit exist to invite animals to disperse the swallowed seeds. A Kobe University research team found that plants targeting insects rather than birds or mammals for this service are more common than previously thought. These plants produce dust-like seeds and fruit suitable for the minute, ground-dwelling animals.

Whether it’s strawberries, apples or grapes, the reason why plants make tasty fruit is to invite and reward animals to also eat and then disperse their seeds, which are smooth and sturdy for just that purpose. Given the size of most seeds, it’s natural that the animals associated with this are mostly birds and mammals. Incidentally, this is also why fruit are often red and dangle from branches. This allows the intended dispersers to easily see and reach the fruit. Insects, on the other hand, while they are often associated with plant pollination, are not seen as important for dispersing ingested plant seeds, mostly because the animals’ minute size wouldn’t allow for the safe passage of the seed through the animal. However, there are plants that produce dust-like seeds embedded in whitish and somewhat translucent fruit that are difficult to see from above and that fall to the ground as soon as they are ripe. And while this makes insects the prime candidates, it has not been known who the actual dispersers are.

The Kobe University botanist SUETSUGU Kenji has an extensive background in studying interactions between plants and arthropods (animals like insects, crabs, and spiders), with a particular focus on dust-seeded plants in Japan. He and his team travelled to Amami-Oshima Island in Japan where a shrub-like plant called Rhynchotechum discolor produces such translucent fruit with dust seeds. The researchers took automated night photographs of the fruit on the ground to find out who eats them and additionally captured insects in the plants’ vicinity (using a mixture of Kirin beer and the soft drink Calpis, both produced in Kobe University’s home region of Kansai). They then put the captured insects into containers to search their excrements for plant seeds and, with a separate feeding experiment, to find out how many of the seeds they eat can germinate.

Their findings, published in the journal Plants, People, Planet, confirmed that insects, specifically camel crickets, were the primary consumers of the fruit. Moreover, the captured insects’ excrement contained numerous seeds, about 80% of which were fully viable. “This result provides the first evidence of insects acting as seed dispersers for a light-harvesting, green plant in regions inhabited by land-dwelling mammals,” says Suetsugu. Previously, seed dispersal by insects was thought to occur only in special situations. There is the case of the weta, gigantic, flightless crickets home to New Zealand, that have taken on ecological functions usually associated with ground-dwelling mammals that don’t exist there. Otherwise, the ability of insects to disperse dust-sized seeds was understood to be largely restricted to heterotrophic plants. These non-green plants don’t harvest light but eat underground fungi and get what nutrients and energy they need from there, so their seeds can be tiny. Suetsugu explains, “Our findings challenge the notion that insect-mediated seed dispersal is a special case and suggest that it may be more widespread and ecologically important than previously understood.”

This discovery excites Suetsugu for another reason: “It also contributes to the understanding of the evolution of dust seeds. Because they are minute and contain minimal energy reserves, their evolution has often been associated with heterotrophy. However, our research on Rhynchotechum discolor suggests that dust seeds can evolve from other selective pressures: Given that smaller seeds are more likely to survive digestive processes, a small seed size could have evolved as an adaptation to convert seed predators into seed dispersers.”

In their paper, the research team notes that the shrub they investigated is likely not unique: “The fruit and seed morphology and coloration of other members of Rhynchotechum parallel those seen in R. discolor, suggesting that seed dispersal by camel crickets is widespread within the genus, which comprises 16 species. In a broader ecological context, similar seed dispersal systems might be found among plants with dust seeds, which are present in at least 13 families.” Suetsugu adds: “We have laid the groundwork for future studies to investigate similar interactions in other regions and with other plant species. This research enhances our knowledge of how plants adapt to their environments and the roles that different organisms play in their life cycles.”

This research was funded by the Japan Science and Technology Agency (grant JPMJPR21D6). It was conducted in collaboration with a researcher from the University of Tokyo.

Kobe University is a national university with roots dating back to the Kobe Commercial School founded in 1902. It is now one of Japan’s leading comprehensive research universities with nearly 16,000 students and nearly 1,700 faculty in 10 faculties and schools and 15 graduate schools. Combining the social and natural sciences to cultivate leaders with an interdisciplinary perspective, Kobe University creates knowledge and fosters innovation to address society’s challenges.

The shrub Rhynchotechum discolor produces dust-like seeds embedded in whitish and somewhat translucent fruit that are difficult to see from above and that fall to the ground as soon as they are ripe.

Camel crickets were the main consumers of the fruit of the shrub Rhynchotechum discolor.

Credit

TASHIRO Yohei

The analysis of the excrements of camel crickets captured in the vicinity of the shrub showed that they contained numerous intact-looking seeds.

Feeding experiments on captured camel crickets showed that around 80 percent of the seeds ingested and later excreted by camel crickets were fully viable and could germinate.

Credit

SUETSUGU Kenji

Journal

Plants People Planet

DOI

10.1002/ppp3.10556 

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Unlikely allies: camel crickets play a role in the seed dispersal of an Asian autotrophic shrub

Article Publication Date

7-Aug-2024