Wednesday, September 03, 2025

An eye for the sky

Bees use the sun's position in the sky for navigation – even on cloudy days

University of Konstanz

The hunt for nectar can take honeybees kilometres away from their hive into unknown territory – and yet, they always find their way back. The sun's position in the sky serves as a kind of compass for bees, even when clouds or other objects block it from view. They owe this ability to the special structure of their complex eyes, which they use to analyze patterns of polarized light in the sky that are invisible to humans.

A research team from the University of Konstanz and the University of Ljubljana has shed light on the visual properties of this specialized part. In their recent study published in Biology Letters of the Royal Society Publishing, the team examines how some light detector cells in bees' eyes are connected to each other. They discovered that in the skyward-facing area of the bee's eye, a signal received by one cell also appeared in others. This unexpected connection produces a less-detailed but more accurate image of polarized light in the sky.

One facet among many
Unlike the human eye, in which a single lens focuses the light from the environment onto our visual cells, bees' eyes are comprised of thousands of individual facets (ommatidia), each one with its own lens. These are known as complex eyes. In the case of bees, the complex eyes contain different specialized areas. "Most of the facets provide a sharp image of the surroundings. However, the upper region of the eyes contains a group of ommatidia that operate differently and are responsible for detecting polarized light in the sky. We took a closer look at this area”, explains Georgios Kolyfetis, co-author of the study. Kolyfetis is a doctoral researcher from James Foster's research team in the Department of Biology at the University of Konstanz

"Light-detecting cells in each of these upper facets are less sensitive than in the facets elsewhere. This keeps bees from getting blinded as they use this part of their eyes to look at the daytime sky", he adds. This is clearly useful, yet it comes at a cost: The reduced sensitivity of these facets prevents bees from detecting subtle changes in the sky. "While they see the rest of the world in more detail, bees see the sky more like a watercolour painting in which adjacent brush strokes blend into each other and details are hidden", explains James Foster, who led the study. "But this is exactly what makes this part of the eye particularly good at detecting large-scale polarization patterns in the sky."

Working together to get the full picture
To understand this, it is worth taking a look at how the human eye works. Our eyes focus light onto individual pixels and use them to construct an overall picture. At night or in poor lighting, this precise sight is no longer possible. The human eye compensates by combining multiple pixels together. A loss of detail is the trade-off for amplifying the light signal. Scientists call this process "spatial summation". This study reveals that the upper group of facets in bee eyes work together in the same way – and around the clock, not just at night.

However, the function is not exactly the same. "In mammalian and human eyes, nerve cells combine the signals of multiple light receptors and send the joint signal on to the brain. In the case of bees, some of the light cells are directly connected to each other", explains neurobiologist Gregor Belušič from the University of Ljubljana. "Each individual facet thus also responds to what neighbouring facets see."

Seeing what's important
What purpose does this serve? The blurry image of the space above them can help bees to tune out unimportant information and only focus on the big picture. "Bees register and analyze the polarization pattern of light in the sky. Based on this information, they determine the sun's position and align their inner compass accordingly. They simply blend out disruptions like clouds or branches overhead", Kolyfetis concludes.

Discovering this function in bee eyes is interesting not only from a biological perspective, but it could be used to further develop modern technologies. "Autonomous vehicles could also benefit from this strategy for navigation. Cameras pointed at the sky could serve as a kind of backup compass if GPS and magnetic signals are unreliable or fail", Foster says. Since bees are able to perform this feat with a small group of facets, "artificial bee eyes" could provide an inexpensive way to supplement other autonomous navigation systems.

Key facts:

Original publication: George E. Kolyfetis, Gregor Belušič, James J. Foster: „Electrophysiological recordings reveal photoreceptor coupling in the dorsal rim areas of honeybee and bumblebee eyes” (2025), Biol. Lett. 21: 20250234; DOI: 10.1098/rsbl.2025.0234
Georgios Kolyfetis is a doctoral researcher in the field of neurobiology at the University of Konstanz. His research focuses on bee sight.
Dr James Foster is a neurobiologist at the University of Konstanz. His research centres on how animals detect and respond to polarized light.
Professor Gregor Belušič is a neurobiologist at the University of Ljubljana, Slovenia. His research is focused on the physiology of insect visual systems.

Journal

Biology Letters

DOI

10.1098/rsbl.2025.0234

Gray seals perplex scientists with lack of response to flu infection

'That’s the big question we’re trying to understand – why is there a difference in the response in two different species that occupy the same space; why is one susceptible to the disease?'

University of Connecticut

Something strange happens when two kinds of seals living in the waters around Cape Cod get infected with influenza – harbor seals get sick but gray seals don’t.

Scientists know that both gray seals and harbor seals can contract influenza. But, generally, only harbor seals get sick and may die from the virus.

This perplexing phenomenon led Milton Levin ‘04 Ph.D., associate research professor of pathobiology and veterinary science in the College of Agriculture, Health and Natural Resources (CAHNR), and his collaborators to investigate if a difference in a piece of the immune system called cytokines could be responsible for this difference.

“That’s the big question we’re trying to understand – why is there a difference in the response in two different species that occupy the same space; why is one susceptible to the disease?” Levin says.

Cytokines are a type of small protein produced by immune cells that work on other immune cells. They play a critical role in coordinating the body’s immune and inflammatory responses.

“They help initiate an immune response and then they help tamp down the immune response once a threat is gone,” Levin says.

Surprisingly, the team found no difference between the cytokine profiles in the gray seal pups that had contracted influenza and those that didn’t. These findings were published in Journal of Wildlife Diseases.

This indicates that the gray seals’ immune systems are not responding to the presence of the virus, or that the virus tamps down the immune response so much the scientists couldn’t detect it.

“Right now, it seems that the seals are not responding at all to influenza, and that’s probably why we’re not seeing clinical signs and why they don’t die,” Levin says.

This is not only a departure from what the researchers expected to see, but from research in many other kinds of animals. Other studies have found clear differences in the cytokine profiles of animals infected with a virus versus those that were not.

Levin and his team collected blood samples from over 100 gray seal pups. In the lab, they used a commercially available kit to measure the presence or absence, and concentration of 13 different cytokines. The kit was originally designed for canines, but Levin’s previous research established its efficacy for seals since the two groups are evolutionarily related.

Levin suggests the lack of cytokine response could be a protective mechanism that prevents the gray seals from getting sick. In humans, sometimes when we encounter a pathogen the body mounts a “cytokine storm,” an unregulated response where the immune system is just firing on all cylinders. This kind of response causes more damage than the pathogen the body is trying to fight.

“If we can understand why gray seals don’t generate that response, that could tell us more about the immune response in general in marine mammals versus other species,” Levin says.

The next step of this research is to measure cytokines in harbor seals. However, collecting samples from harbor seal pups will be a challenge. Gray seals separate from their mothers after just a few weeks and stay on the beach where researchers have easy access to them. Harbor seals, however, stay with their mothers for four to six weeks; and grown seals are much too large for researchers to handle safely.

The overarching goal of the research Levin and his collaborators have been conducting for over a decade is to understand how viruses circulate in marine populations and what makes an animal more or less susceptible to illness and death from these infections.

“We’re trying to understand how pathogens, viruses, and influenza in particular, are being passed between species and if it is being transmitted to humans or are humans transmitting it to seals,” Levin says.

Journal

Journal of Wildlife Diseases

DOI

10.7589/JWD-D-24-00166

Method of Research

Experimental study

Subject of Research

Animals

Article Title

Gray Seal (Halichoerus grypus) Pups Fail to Mount an Inflammatory Cytokine Response to Influenza A Virus

Registration opens for the World Conference of Science Journalists 2025 in South Africa

Social justice the theme of the in-person event taking place from 1 to 5 December 2025 in Pretoria, South Africa

World Conference of Science Journalists 2025

Registration for the World Conference of Science Journalists 2025 (WCSJ2025), due to take place 1-5 December at the CSIR International Convention Centre in Pretoria, is now open.

This is an unmissable event for science journalists, science communicators and scientists wanting to publicise their work. The international biennial conference is taking place for the first time ever on African soil and presents a unique opportunity for everyone interested in communicating science to hone their craft, to network with their peers, and to find stories about groundbreaking African science.

The overarching theme is “Science journalism and social justice: journalism that builds understanding and resilience”. The programme is wide-ranging and includes discussions and practical workshops covering wellbeing for people and the planet; the state of the profession; the art of communication; and misinformation, disinformation and fake news.

A small sample of some of the sessions on the programme includes:

Bringing social justice into ocean science reporting

The world’s oceans are facing grave threats from climate change, overfishing, pollution, and biodiversity loss. Emerging industries such as deep-sea mining and marine geoengineering are adding further pressure. As well as ensuring that reporting on these topics is scientifically accurate, journalists must ensure that the voices of those most impacted are included. Journalists on this panel are from Australia, South Africa, India and the USA.

When industry endangers health and ecosystems

Can science journalism fight environmental injustice? In this session, learn how journalists safely expose polluters, turn data into evidence, and amplify marginalised voices. Through real cases and tools, the panellists will show how media can drive policy change and reduce pollution inequalities.

AI – Friend or Foe?

Artificial Intelligence is transforming journalism – supercharging investigations while enabling sophisticated deepfakes and automated disinformation that challenge both newsroom survival and editorial integrity. This session examines how journalists are fighting back, turning AI’s analytical power against digital manipulation and disinformation networks while maintaining trust in an era where seeing is no longer believing.

Reporting under fire: science journalism in conflict zones and authoritarian regimes

This session offers strategies for resilience and highlights the role of journalism in defending scientific truth and social justice. In regions where war, political repression, or disaster intersect with scientific misinformation, science journalists face grave risks. This session explores how journalists from Yemen, Lebanon and Nigeria confront censorship, security threats, and digital suppression to still report on public health, climate, and tech stories.

Challenging times: Communicating about climate change when politics promotes denial and misinformation

The World Meteorological Organization confirmed 2024 as the warmest year on record, yet a cocktail of fake news, narratives without evidence, and economic interests are promoting climate change denialism. What role has science journalism to play in countering this trend and dismantling such narratives?

Telling the stories of astronomy in Africa

Africa has become a key player in global astronomy, with South Africa hosting the largest share of the Square Kilometre Array (SKA), as well as the Southern African Large Telescope (SALT) and other projects. This session explores the major strides made since the early days of optical astronomy in South Africa, and what it means for international science reporting. Speakers will examine the challenges of covering “big science” projects, the politics of funding, and how to make cosmic research accessible to broad audiences.

Ends

Media Contact Information

Mr Zamuxolo Matiwana

Local organising committee member

Telephone number: 082 901 2910

Email: info@wcsj2025.org

About WCSJ2025

The World Conference of Science Journalists takes place every two years and is the largest international event for science journalists to gather as peers, helping one another learn, grow, and thrive. It is an initiative of the World Federation of Science Journalists. During the conference, attendees will enjoy seminars, workshops, lectures and access to expertise from around the world.

An engaging, relevant and stimulating programme of content which will offer opportunities for both inspiration and growth, and a bouquet of day trips and longer options to explore our science and the natural and cultural glories of our country.

WCSJ2025 gives science journalists and their stakeholders an opportunity to interact, share ideas and information, stimulate debate and discussion and form solutions regarding how science journalists can contribute to building resilience in the face of the many challenges the people of the world face.

About SASJA

The SA Science Journalists’ Association is a non-profit, non-governmental, national organisation for science and technology writers. SASJA is the professional association of science media practitioners in South Africa. It is a non-profit, non-governmental, national organisation, mainly representing the interests of science and technology (including health, environmental, engineering, sports) journalists and other science media practitioners. SASJA encourages networking and training in the interest of sound science journalism.

SASJA strives to improve communication between the science community and general society by evaluating information according to strict journalism ethics and presenting it either in print, or via the electronic media – television, radio and internet – to the public.

The conference is organised by the South African Science Journalists’ Association (SASJA) and the Science Diplomacy Capital for Africa (SDCfA), an initiative and entity of the National Department of Science, Technology and Innovation (DSTI), in collaboration with the Council for Scientific and Industrial Research (CSIR).

Bacteria that ‘shine a light’ on microplastic pollution

American Chemical Society

Microplastics are tiny, plastic fragments — many too small to see — found in the air, soil and water. Measuring their abundance in nature can direct cleanup resources, but current detection methods are slow, expensive or highly technical. Now, researchers publishing in ACS Sensors have developed a living sensor that attaches to plastic and produces green fluorescence. In an initial test on real-world water samples, the biosensor could easily detect environmentally relevant levels of microplastics.

Currently, scientists detect microplastics in water samples using microscopes or analytical tools, such as infrared or Raman spectroscopy. While these techniques are accurate, they require multiple steps to prepare samples before analysis and can be expensive and time-consuming. In a step toward a simpler method, Song Lin Chua and colleagues created a living microplastics sensor from the bacterium Pseudomonas aeruginosa. This bacterium is commonly found in the environment and can naturally establish biofilms on plastic materials, though some strains are opportunistic human pathogens. The team wanted to modify the bacterium slightly to create a living sensor that easily detects microplastics in water samples.

The researchers added two genes to a non-infectious laboratory strain of P. aeruginosa to make the sensor. One gene produces a protein that activates when bacterial cells contact plastic, and the other gene produces a green-fluorescent protein in response. In lab tests, the engineered bacteria fluoresced in vials containing plastic pieces and a growth medium, but not in separate vials of other materials such as glass and sand. A measurable fluorescence was produced within 3 hours for various plastics, including polyethylene terephthalate (recycling symbol 1) and polystyrene (recycling symbol 6). Additionally, the modified bacterial cells stayed active for up to 3 days in the refrigerator (39 degrees Fahrenheit, 4 degrees Celsius), which the researchers say indicates it could be transported to field locations.

To test the living microplastics sensor as an environmental monitoring tool, the researchers added the engineered P. aeruginosa to seawater from a city waterway. The seawater was first filtered and then treated to remove organic matter before the bacteria were added. Based on the fluorescence intensity values, the water samples contained up to 100 parts per million of microplastics. Further water analysis with Raman microspectroscopy revealed that the microplastics were primarily biodegradable types, such as polyacrylamide, polycaprolactone and methyl cellulose, which the biosensor detected despite the initial tests being done on traditional polymers.

“Our biosensor offers a fast, affordable and sensitive way to detect microplastics in environmental samples within hours,” says Chua. “By acting as a rapid screening tool, it could transform large-scale monitoring efforts and help pinpoint pollution hotspots for more detailed analysis.”

The authors acknowledge funding from the Environment and Conservation Fund, Health and Medical Research Fund, Research Centre for Deep Space Explorations, and Pneumoconiosis Compensation Fund Board.

The paper’s abstract will be available on Sept. 3 at 8 a.m. Eastern time here: http://pubs.acs.org/doi/abs/10.1021/acssensors.5c01120

###

The American Chemical Society (ACS) is a nonprofit organization founded in 1876 and chartered by the U.S. Congress. ACS is committed to improving all lives through the transforming power of chemistry. Its mission is to advance scientific knowledge, empower a global community and champion scientific integrity, and its vision is a world built on science. The Society is a global leader in promoting excellence in science education and providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, e-books and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a leader in scientific information solutions, its CAS division partners with global innovators to accelerate breakthroughs by curating, connecting and analyzing the world’s scientific knowledge. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.

Registered journalists can subscribe to the ACS journalist news portal on EurekAlert! to access embargoed and public science press releases. For media inquiries, contact newsroom@acs.org.

Note: ACS does not conduct research but publishes and publicizes peer-reviewed scientific studies.

Journal

ACS Sensors

DOI

10.1021/acssensors.5c01120

Article Title

Detection of Microplastics Pollution Using a Green Fluorescent Protein-Based Microbial Biosensor Coupled with Raman Spectroscopy

Article Publication Date

3-Sep-2025

Colorless solar windows: Transforming architecture into clean power plants

Cholesteric liquid crystal coatings enable transparent, unidirectional solar concentrators compatible with modern windows.

Chinese Society for Optical Engineering

A research team led by Nanjing University has introduced a transparent, colorless, and unidirectional solar concentrator that can be directly coated onto standard window glass. Utilizing cholesteric liquid crystal (CLC) multilayers with submicron lateral periodicities, this diffractive-type solar concentrator (CUSC) selectively guides sunlight toward the edge of the window where photovoltaic cells are installed. The study appears in PhotoniX.

Unlike conventional luminescent or scattering-based concentrators, which often suffer from visual distortion, low efficiency, and poor scalability, the new CUSC achieves broadband polarization-selective diffraction and waveguiding without compromising clarity. The device maintains a high average visible transmittance (64.2%) and color rendering index (91.3), enabling clean energy generation without altering the appearance of the window.

“By engineering the structure of cholesteric liquid crystal films, we create a system that selectively diffracts circularly polarized light, guiding it into the glass waveguide at steep angles,” said Dr. Dewei Zhang, co-first author. “This allows up to 38.1% of incident green light energy to be collected at the edge.”

Experiments showed that a 1-inch-diameter prototype could directly power a 10-mW fan under sunlight. Modeling suggests a typical 2-meter-wide CUSC window could concentrate sunlight by 50 times, significantly reducing the number of photovoltaic cells required by up to 75%. The system supports integration with high-performance PV cells such as gallium arsenide for enhanced power conversion.

The multilayered CLC films are fabricated via photoalignment and polymerization techniques and are scalable via roll-to-roll manufacturing. The design remains stable under long-term exposure and can be retrofitted onto existing windows for sustainable urban upgrades.

“The CUSC design is a step forward in integrating solar technology into the built environment without sacrificing aesthetics,” said Professor Wei Hu. “It represents a practical and scalable strategy for carbon reduction and energy self-sufficiency.”

Future work will focus on enhancing broadband efficiency, polarization control, and adapting the technology for agricultural greenhouses and transparent solar displays. Their vision: to turn passive glass into active, energy-generating surfaces worldwide.

Journal

PhotoniX

DOI

10.1186/s43074-025-00178-3

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Colorless and Unidirectional Diffractive-type Solar Concentrators Compatible with Existing Windows

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Wednesday, September 03, 2025

An eye for the sky

Journal

DOI

Gray seals perplex scientists with lack of response to flu infection

Journal

DOI

Method of Research

Subject of Research

Article Title

Registration opens for the World Conference of Science Journalists 2025 in South Africa

Bacteria that ‘shine a light’ on microplastic pollution

Journal

DOI

Article Title

Article Publication Date

Colorless solar windows: Transforming architecture into clean power plants

Journal

DOI

Method of Research

Subject of Research

Article Title

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