Tuesday, April 28, 2026

‘Chameleon’ bees change color with the weather

Queen Mary University of London

Sweat Bee — image:
A sweat bee in the wild (photo by Jeremiah Bender who retains the copyright on this images. This may be used in any article in association with this story).
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Credit: A sweat bee in the wild (photo by Jeremiah Bender who retains the copyright on this images. This may be used in any article in association with this story).

Some bees really do change colour with the weather, according to new research that shows humidity can temporarily alter the shimmering hues of certain species.

In a study published today in Biology Letters, scientists led by Dr Madeleine Ostwald of Queen Mary University of London found that moisture in the air can cause sweat bees to change colour — and then change back again when conditions dry out.

Sweat bees are known for their bright, metallic greens and blues. Until now, reports that their colours could shift have been anecdotal. This new research provides the first experimental proof.

The team studied museum specimens of a North American sweat bee, Agapostemon subtilior. When the bees were placed in dry air, they appeared deep blue. But when humidity increased, they took on a warmer, copper‑green colour. Once dried again, the bees returned to blue.

Unlike most animals, whose colours come from pigments, these bees get their colour from microscopic structures on their bodies that reflect and scatter light at particular wavelengths. The same effect creates the iridescent feathers of hummingbirds and the shifting skin colours of cuttlefish.

In some animals, these tiny structures swell slightly when exposed to moisture, causing them to reflect redder colours. The researchers believe a similar process may be happening in bees, although more work is needed to fully understand the mechanism.

The scientists also looked at colour changes in the wild. By analysing hundreds of public photos from the citizen science app iNaturalist, they compared bee colour with local humidity levels. While many factors influence a bee’s appearance, the team found that bees in drier areas tended to look bluer — matching the lab results.

Interestingly, older museum specimens showed the strongest colour changes. The researchers think this may be because bees’ outer shells slowly degrade over time, allowing moisture to enter more easily.

The findings suggest this colour‑changing effect could be common among bees, which display a wide range of shimmering colours and live in environments ranging from deserts to rainforests.

Insects use colour for many reasons, including temperature control, communication, and camouflage. Whether these subtle colour shifts affect how bees behave or survive is still unknown.

Dr Madeleine Ostwald, Lecturer in Ecology, Conservation & Biodiversity at Queen Mary said: “When people think of bees, they often picture drab, brown honey bees. In reality, bees are incredibly diverse and colourful — and we’re only just starting to understand how their appearance reflects the climate they live in.”

She added: “Most people associate colour‑change with animals like chameleons that actively control it. These bees aren’t choosing to change colour — it’s happening passively, simply in response to the humidity around them. That adds a whole new layer of mystery to why these colours evolved in the first place.”

The study was carried out with researchers Leslie Cervantes Rivera, Jorge De La Cruz and Katja Seltmann from the Cheadle Center for Biodiversity and Ecological Restoration at the University of California, Santa Barbara.

“Humidity induces structural colour change and contributes to biogeographic colour variation in sweat bees” will be published on 00.05 BST April 22, 2026 in Biology Letters

A sweat bee in San Diego County, California. Image from iNaturalist taken by Karen Fraser (user “fraskar”) https://www.inaturalist.org/observations/272490405, CC0.

Credit

Image from iNaturalist taken by Karen Fraser (user “fraskar”) https://www.inaturalist.org/observations/272490405, CC0.

Journal

Biology Letters

Article Title

Humidity induces structural colour change and contributes to biogeographic colour variation in sweat bees

Article Publication Date

22-Apr-2026

Study looks to Africa to best support Aussies living with chronic conditions

Curtin University researchers will lead an international study in South Africa aimed at implementing community-delivered interventions that address mental health and substance use-related barriers to staying engaged in treatment for chronic conditions

Curtin University

Professor Bronwyn Myers with community health workers in South Africa — image:
*Professor Bronwyn Myers (second from left) with some of the community health workers Curtin researchers will be working with in South Africa.*
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Credit: Curtin University

Curtin University researchers will lead an international study in South Africa aimed at implementing innovative community-delivered interventions that address mental health and substance use-related barriers to staying engaged in treatment for chronic conditions such as diabetes and high blood pressure.

Led by Curtin enAble Institute Director Professor Bronwyn Myers, the project will run for five years after being awarded a $2.1 million National Health and Medical Research Council Global Alliance for Chronic Diseases Strengthening Health Systems grant.The project is being conducted in partnership with the South African Medical Research Council.

Professor Myers said despite healthcare being available, many people stopped treatment for chronic conditions because untreated mental health or substance use disorders made it harder to stay engaged.

“Community health workers already visit people in their homes, so they’re often the first to see when someone has missed appointments or stopped taking medication but they haven’t always had the training or support to respond effectively to mental health and substance use issues,” Professor Myers said.

“This study will test what happens when those home visits are backed by better training and peer support for mental health and substance use recovery, so community care teams can recognise the problem early, respond without stigma and help people reduce mental health and substance use barriers to staying connected to care instead of falling through the cracks.”

The study will test a program named Siyakhana - an isiXhosa word meaning ‘we build each other up’. It involves skills-based mental health and substance use training for community health workers and embeds peer recovery coaches with lived experience directly into community health teams to deliver additional mental health and substance use supports to patients.

The study will follow the outcomes of more than 5000 patients, measuring whether the approach helps people re‑engage with care and delivers value for money at a health‑system level.

Professor Myers said South Africa was the best place to conduct the study before applying the findings to Australia.

“As South Africa already has a large, established community health worker program, this is the ideal place for testing this health system strengthening intervention properly, at scale and much faster than we currently could in Australia where community health worker programs are only beginning to be implemented,” Professor Myers said.

Professor Myers said the approach responded to pressures facing both countries.

“Australia faces rising chronic disease rates, workforce shortages and growing demand for community‑based care, particularly in regional and underserved areas,” she said.

“By generating strong, real‑world evidence in South Africa, we can guide smarter, more cost‑effective decisions about how Australia expands community health workers and peer‑supported care.”

For more information about the Curtin enAble Institute, visit here.

USC-led team receives funding to build next-generation medical device that uses tears to monitor health

Researchers from USC and the California Institute of Technology aim to develop a tiny sensor and drug delivery system, implanted near the eye, with dry eye disease as its first target

Keck School of Medicine of USC

A team of researchers from USC in collaboration with the California Institute of Technology (Caltech) have received approximately $7.8 million from the Advanced Research Projects Agency for Health (ARPA-H) Ocular Laboratory for Analysis of Biomarkers (OCULAB) program to build a medical device that could transform testing and treatment for a range of health conditions. The project, Personalized Automated Continuous Treatment for Eye Plus Systemic Disease (PACE+), aims to develop an implantable system, placed near the eye, that can measure biomarkers in tears to monitor dry eye disease (DED) and automatically deliver medication to treat the condition. The technology uses remote sensing capabilities and could be expanded for use in a range of other diseases, such as cancer, diabetes and neurological conditions.

ARPA-H, an agency within the U.S. Department of Health & Human Services, focuses on rapidly accelerating innovation to solve society’s most pressing health problems. OCULAB, which is led by ARPA-H program manager Calvin Roberts, MD, is focused on the development of a tear-based system that can measure biomarkers of DED and deliver medication for personalized treatment. ThePACE+ project is well positioned to meet this challenge, drawing on longstanding collaborations that unite clinical and biological expertise with advanced biomedical engineering.

The OCULAB approach centers on tears as a diagnostic fluid. Tears contain many of the same biomarkers as blood but are easier to collect. Compared to intermittent blood draws, continuous monitoring of tears can track disease states more chronically with less burden to patients.

“Many people don’t realize how much information is in our tears. Because we can collect this information non-invasively and in real time, it can help personalize the approach to managing and treating a number of health conditions,” said Mark S. Humayun, MD, PhD, director of the USC Dr. Allen and Charlotte Ginsburg Institute for Biomedical Therapeutics and co-director of the USC Roski Eye Institute at the Keck School of Medicine of USC, who is leading the PACE+ project team.

An implant for dry eye disease

In DED, which affects more than 20 million people in the United States, tears do not adequately lubricate the eyes, causing dryness, pain and inflammation. Diagnosing and treating DED involves periodic testing and daily eye drops, which many patients find uncomfortable, inconvenient or difficult to adjust when symptoms change.

Humayun and his team will work to develop a closed-loop system that keeps DED symptoms under control, similar to the way an insulin pump monitors blood sugar and automatically adjusts dosing to keep it stable.

They intend to build a tiny implant, the size of a grain of rice, that can be placed through a small existing opening in the eyelid (corner of the eye) during a quick, painless procedure. A chip inside the implant measures tear biomarkers linked to DED symptoms and sends the data to the patient’s smartphone. The phone then automatically dispatches medication as needed through a second small device, tucked between the eye and lower lid. This helps manage symptoms as they fluctuate without requiring any action from the patient.

The researchers face several technical challenges. Because biomarker levels in tears are typically lower than levels in blood, the system must be highly sensitive. Meanwhile, most existing biosensors can measure markers for days or weeks, but the PACE+ system’s goal is to work for up to six months.

Power and data transfer are also difficult with such a small device. The system may be powered using a biofuel cell, which uses an energy source from the human body, or near-field communication (NFC), which wirelessly supplies power from a nearby device, such as a smartphone. NFC may also be used to transfer data between the implant and the patient’s smartphone.

Building a tear-based device

Over the next 18 months, the researchers will focus on engineering and validating the system. This includes demonstrating in the lab that the sensor can accurately measure DED biomarkers, confirming that the system can be safely positioned around the eye and conducting early tests in preclinical models. If the team meets these milestones, the project is eligible for up to $9.3 million in additional funding.

Beyond DED, the team will also explore whether the system can reliably measure depression-related biomarkers, including serotonin. The technology could someday be used for detecting and monitoring breast cancer, prostate cancer, Alzheimer’s disease, multiple sclerosis, infertility and a number of other conditions with known tear-based biomarkers.

“This has never been done before, anywhere in the world,” said Humayun, who is also the inaugural holder of the Dennis and Michele Slivinski Chair in Macular Degeneration Research and University Professor of ophthalmology, biomedical engineering, and stem cell biology and regenerative medicine. “It’s a moonshot, but it could give us a far better way to monitor and manage some of the world’s most common and serious diseases.”

About this research

In addition to Humayun, the project’s other investigators include experts in dry eye Sarah Hamm-Alvarez and Maria C. Edman from the Keck School of Medicine of USC, University of Southern California; drug development expert Stan Louie from the Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California; and bioelectromagnetics expert Gianluca Lazzi from the Keck School of Medicine and the Viterbi School of Engineering, University of Southern California. California Institute of Technology (Caltech) collaborators include microelectromechanical systems (MEMS) expert Yu-Chong Tai; high-performance, low-power, mixed-mode integrated systems expert Azita Emami; biosensor design expert Wei Gao; and artificial intelligence and machine learning expert Yisong Yue. The project also includes biomanufacturing expert Andrew Urazaki from Urazaki Corp.

This research is funded, in part, by the Advanced Research Projects Agency for Health (ARPA-H). The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the U.S. Government.

First actual measurement of “attempt time” in nanomagnets after 70 years of assumptions

Tohoku University

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Title image
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Credit: ©Shun Kanai

A compass always points north – or does it? Magnets normally maintain a stable direction of magnetization, pointing from south to north (S→N). However, this direction can change under strong magnetic fields or heat. For example, a compass placed near a strong magnet may no longer point in the right direction. Magnets can also lose their magnetism when exposed to high levels of heat. This isn’t just relevant to wayfinding during your camping trips – if the magnets in hard drives and memory storage devices are affected, it could mean losing all of your precious data.

Researchers at Tohoku University sought to better understand the intricate ways in which this thermally-activated switching occurs in nanomagnets, and successfully measured it experimentally for the very first time.

This switching behavior can be understood using something called an energy landscape. Two stable magnetization directions exist (such as south and north), separated by an energy barrier. Thermal fluctuations can occasionally push the magnetization over this barrier, causing the direction to switch.

This stability is the principle behind magnetic storage technologies such as hard disk drives. In these devices, each bit of information is stored in a tiny magnet. The height of the energy barrier is proportional to the volume of the magnet. As storage density increases and the magnets become smaller, the barrier becomes lower, increasing the risk that thermal fluctuations may flip the magnetization and destroy stored information.

The probability of such thermally activated switching follows the Arrhenius law. In this model, the magnet repeatedly attempts to cross the energy barrier with a characteristic time called the attempt time (τ₀). For nearly 70 years, this attempt time has been assumed to be about one nanosecond. However, it had never been successfully measured experimentally.

To measure attempt time, the research team fabricated nanomagnet devices, characterized their geometry using scanning electron microscopy (SEM), and measured the way they responded – such as how it switches between two opposite magnetization states at room temperature.

The researchers developed a new experimental and analytical approach that allows the Arrhenius law to be tested without changing temperature. Using this approach, they found that the attempt time is about 4–11 nanoseconds, which is more than ten times longer than previously assumed.

“This parameter has been assumed for decades but had never been directly measured,” says Shun Kanai, Associate Professor at the Research Institute of Electrical Communication (RIEC) at Tohoku University. “Our experiments show that the fundamental switching attempts of nanomagnets occur much more slowly than previously thought.”

The study also suggests that collective spin excitations inside the magnet, known as spin waves, influence the switching process and slow down the effective switching attempts.

Now that attempt time has been experimentally measured, this value can serve as a more accurate foundation for further developing and evaluating the stability of magnetic devices such as hard disk drives and magnetoresistive random access memory. Emerging computing technologies like spintronic probabilistic computing devices (p-bits) which intentionally use thermal fluctuations may also benefit from this finding.

The results were published in Communications Materials on April 21, 2026.

Energy barrier model of magnetization switching. Two stable magnetization states are separated by an energy barrier. Thermal fluctuations occasionally allow the magnetization to cross the barrier, causing switching.

Left: Scanning electron microscopy (SEM) image of a fabricated nanomagnet device (scale bar: 50 nm). The magnetization of the nanomagnet can take two opposite orientations. Right: Representative random telegraph noise (RTN) signal measured at room temperature. The voltage switches between two discrete levels, reflecting thermally activated magnetization reversal between the two states.

Experimental determination of the attempt time. The energy barrier was systematically controlled by varying nanomagnet size and magnetic fields. The resulting Arrhenius plot allowed the attempt time τ₀ to be determined under constant temperature conditions.