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Wednesday, December 03, 2025

Fearless frogs feast on deadly hornets

Kobe University

251204-Sugiura-Stings-Frog_eats_hornet — image:
Kobe University ecologist SUGIURA Shinji discovered that the black-spotted pond frog seems to be unharmed and undaunted by venomous stings from hornets such as the Asian giant hornet, the largest in the world.
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Credit: Shinji Sugiura, Ecosphere 2025 (DOI 10.1002/ecs2.70457)

A remarkable resistance to venom has been discovered in a frog that feasts on hornets despite their deadly stingers. This frog could potentially serve as a model organism for studies on mechanisms underlying venom tolerance.

While just the sight of a hornet’s stinger is enough to fill many of us with dread, some animals, such as some birds, spiders and frogs, are known to prey on adult hornets. The venom injected by their stingers can cause sharp, intense pain as well as local tissue damage and systemic effects such as destruction of red blood cells and cardiac dysfunction, which may even be fatal. But whether the animals that hunt hornets are able to tolerate the venomous stings, or just manage to avoid them, has remained unclear. “Although stomach-content studies had shown that pond frogs sometimes eat hornets, no experimental work had ever examined how this occurs,” says Kobe University ecologist SUGIURA Shinji.

To test whether frogs avoid or tolerate these potentially deadly hornet stings, Sugiura presented individual adult pond frogs with workers of three hornet species, Vespa simillima, V. analis, and V. mandarinia, under laboratory conditions. Each frog was used only once, and was matched to fit the size of their prospective hornet prey, with larger frogs preferentially matched with Asian giant hornet (V. mandarinia) prey.

In the journal Ecosphere, Sugiura submits striking evidence that adult pond frogs actively attacked workers of the three hornet species. What’s more, he also reports that 93%, 87%, and 79% of frogs ultimately consumed V. simillima, V. analis, and V. mandarinia, respectively, despite being stung into the mouth or even into the eyes. “While a mouse of similar size can die from a single sting, the frogs showed no noticeable harm even after being stung repeatedly. This extraordinary level of resistance to powerful venom makes the discovery both unique and exciting,” says Sugiura.

Previous studies have suggested that pain and lethality of venomous stings are not necessarily correlated, with some stinging bees, wasps and ants delivering extremely painful, non-lethal stings while others cause little pain despite high lethality. This could mean that the frogs in this study have developed a double tolerance to these stings, which has enabled them to successfully prey on hornet workers.

“This raises an important question for future work,” he adds, “namely whether pond frogs have physiological mechanisms such as physical barriers or proteins that block the pain and toxicity of hornet venom, or whether hornet toxins have simply not evolved to be effective in amphibians, which rarely attack hornet colonies.” These frogs could, therefore, also serve as valuable model organisms for studying the physiological mechanisms underlying venom tolerance and pain resistance in vertebrates moving forward.

This research was funded by the Japan Society for the Promotion of Science KAKENHI (grants JP23K18027 and JP24K02099).

Kobe University is a national university with roots dating back to the Kobe Higher Commercial School founded in 1902. It is now one of Japan’s leading comprehensive research universities with over 16,000 students and over 1,700 faculty in 11 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.

Journal

Ecosphere

DOI

10.1002/ecs2.70457

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Pond frog as a predator of hornet workers: High tolerance to venomous stings

Article Publication Date

4-Dec-2025

The venomous stinger of an Asian giant hornet (Vespa mandarinia). The venom injected by this stinger can cause sharp, intense pain as well as local tissue damage and systemic effects such as destruction of red blood cells and cardiac dysfunction, which may even be fatal.

Credit

Shinji Sugiura, Ecosphere 2025 (DOI 10.1002/ecs2.70457)

The black-spotted pond frog shows remarkable tolerance to venomous stings from an Asian giant hornet. The stings caused no visible harm and the frog behaved normally after predation. Close-up views of the hornet’s stinger embedded in the frog’s mouth are shown in the circular insets in (C) and (D).

Almost all frogs in the study attacked the hornets, and although the hornets stung the frogs repeatedly, 93%, 87%, and 79% of frogs ultimately consumed *Vespa simillima*, *V. analis*, and *V. mandarinia*, respectively.

Credit

Shinji Sugiura, Ecosphere 2025 (DOI 10.1002/ecs2.70457)

Tuesday, December 02, 2025

Making quieter dental drills to reduce dental anxiety

By studying the aeroacoustics of a dental drill, researchers can pinpoint the anxiety-causing sounds and design drills to lessen them.

Acoustical Society of America

image:
A dental drill being used in a patient’s mouth.
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Credit: Tomomi Yamada

HONOLULU, Dec. 2, 2025 — Dental anxiety, also known as odontophobia, prevents people from getting their regular cleanings and keeping up with necessary dental hygiene.

One aspect of the anxiety comes from the sound of the dental drill, which makes a high-pitched whining sound. As a dentist, Tomomi Yamada has witnessed discomfort and fear in her patients firsthand.

“Originally, I was doing research on dental materials, but I realized that almost no one — not even dentists — was tackling this sound problem scientifically,” Yamada said.

Yamada, an assistant professor at the University of Osaka’s graduate school of dentistry, will present her work Tuesday, Dec. 2, at 8:20 a.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in Honolulu, Hawaii.

To understand the aerodynamics of the drill, Yamada and her collaborators from the University of Osaka, Kobe University, and National Cheng Kung University used Japan’s flagship supercomputer to conduct large-scale aeroacoustics simulations. They analyzed the internal and external airflow of the dental drill, which is powered by compressed air and rotates at about 320,000 revolutions per minute.

From these simulations, they were able to visualize how air moves through and around the drill to create the noise.

“Our research showed that just making the drill quieter isn’t enough to make the sound less unpleasant,” Yamada said. “What really matters is improving its sound quality.”

The researchers also tested the psychological effects of the dental drill, which can generate high-pitched sounds reaching nearly 20 kilohertz, with children and adults. They found that younger listeners had different reactions to the drill, perceiving the sounds as louder and more unpleasant.

“This indicates that children’s fear of dental sounds is not merely psychological but also physiological in nature,” said Yamada. “Children truly hear these sounds differently, so their fear of dental treatment is a genuine sensory response, not just imagination.”

To address this, Yamada and her colleagues are working on optimizing the blade geometry and exhaust port of the drill to minimize the noise while maintaining the performance.

To get the dental industry to adopt this new technology, achieving a balance between the device’s performance and safety is key, since a quieter drill won’t necessarily get the job done.

“Moving forward, we hope to work with dental manufacturers through industry–academia partnerships, progressing toward commercialization after completing the necessary regulatory and durability testing,” Yamada said.

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Main Meeting Website: https://acousticalsociety.org/honolulu-2025/

Technical Program: https://eppro02.ativ.me/web/planner.php?id=ASAASJ25

ASA PRESS ROOM

In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.

LAY LANGUAGE PAPERS

ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.

ABOUT THE ACOUSTICAL SOCIETY OF AMERICA

The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.

ABOUT THE ACOUSTICAL SOCIETY OF JAPAN

ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan, as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.

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Tuesday, November 25, 2025

Urban natives: Plants evolve to live in cities

Kobe University

251125-Ushimaru-Divergence-Plant — image:
Kobe University ecologist USHIMARU Atushi has been studying the Asiatic dayflower, scientifically known as *Commelina communis*, for over 20 years and realized it grows vigorously in urban environments, making it an ideal subject for investigating the effects this environment has on plants.
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Credit: Nakata Taichi et al., Journal of Ecology 2025 (DOI 10.1111/1365-2745.70193)

While urbanization has restricted and fragmented the natural ecosystems, it also creates new and diverse environmental conditions within towns. A Kobe University research team now found that a plant species that successfully established itself throughout a megacity exhibited distinct and inheritable characteristics that have adapted to the diverse urban environments.

Urbanization has been accelerating since the 1970s, leading to habitat reduction and fragmentation. Many studies have since confirmed a loss in biodiversity and species abundance in urban compared to rural habitats. Kobe University ecologist USHIMARU Atushi has been studying the Asiatic dayflower, scientifically known as Commelina communis, for over 20 years and realized it grows vigorously in urban environments, making it an ideal subject for investigating the effects this environment has on plants. During these studies, his former graduate student NAKATA Taichi (who recently moved to Kyushu University) found something interesting. He says, “While observing the plant in different urban environments, I noticed differences in size, flowers and flowering periods, which got me curious as to what causes these variations.”

The Kobe University team decided to study whether and how different urban habitats affect the plants’ appearance. “It is rare that native plants are capable of thriving in a wide range of environments, from countryside paddy fields to urban roads and pavement cracks,” says Nakata. This is why the study of the effect of urban environments on plants has so far mostly been limited to comparing rural with urban landscapes, but not different urban environments with each other. It also helped that Kobe University is located in the “Keihanshin” megacity comprising Osaka, Kyoto and Kobe. Ushimaru explains, “This region retains a significant amount of farmland within the urban area, providing conditions where we could compare relatively well-preserved farmlands with parks and roadsides.”

In the Journal of Ecology, the ecologists now published that the plants growing in the different habitats had significant differences in various traits, such as height and flowering period. Ushimaru says: “We could clearly show that adaptive radiation occurred, which is what biologists call it when a species diversifies across different habitats. And we found that factors clearly associated with urbanization, in particular elevated ground surface temperatures, artificially shaded environments and decreased soil acidity, drive these differences.” In urban habitats, the maximum ground temperature was about 8ºC higher than in the countryside, and this so-called “heat island effect” was a particularly strong driver of trait diversification.

Up until less than 100 years ago, most of the studied area was occupied by rice paddies and forests, and urbanization really picked up only less than 60 years ago, which means that the variation in traits the Kobe University team found must have evolved within this short time span. In their study, the team was careful to check whether the differences they found were not due to possible random fluctuations in the genetic make-up of the founders of the respective plant populations. However, since they could exclude this, the adaptations they found “are likely attributable to rapid adaptive evolution over only approximately 60 years,” as the researchers write in their paper.

“Moving forward, we want to conduct cultivation experiments that replicate the complex field environments to clarify in what way the different traits are beneficial to the plants. And we also want to know to what degree these adaptations are engraved into the plants’ DNA,” says Ushimaru. His former student concludes saying, “These findings are just the starting point for research on a larger scale.”

This research was funded by the Japan Science and Technology Agency (grant JPMJF2126) and the Japan Society for the Promotion of Science (grant 19K06855). It was conducted in collaboration with a researcher from the University of Hyogo.