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A new paper from the BEE-GUARDS project shows that the honeybee intestine is a hub where nutrition, metabolism, immunity, and brain communication converge.

In this study, published in the Journal of Insect Physiology, researchers from IPSP and ISPAAM of the Italian National Research Council used a proteomic approach to investigate how the middle gut of the honey bee changes in response to different diets, identifying 1,787 proteins involved in digestion, cellular maintenance, stress responses, and host–microbiome interactions.

The results show that the honeybee gut is highly adaptable and can adjust its molecular machinery according to food availability. In particular, a pollen-rich diet promoted proteins that support intestinal structure, nutrient digestion, and antioxidant protection, helping bees maintain metabolism and reduce cellular stress.

By contrast, a sugar-only diet triggered a stress-adaptation response, increasing the levels of proteins involved in preserving cellular stability, repairing damage, and regulating gene expression under nutritional challenges.

The study also highlights the importance of the gut microbiome, including bacterial proteins from beneficial intestinal microorganisms. In addition, the gut microbiome contributes to digestion, nutrient processing, and protection against pathogens, emphasising its network with the host.

Overall, these data show that the honeybee intestine is a dynamic organ capable of balancing digestive functions with stress management and immune defence.

Understanding how nutrition value of food influences gut physiology delivers insights into how bees cope with environmental fluctuations and may help improve conservation and selection strategies to protect colony health in variable ecosystems and in the face of climate change.

Link: https://www.sciencedirect.com/science/article/pii/S0022191026001137?via%3Dihub

Within Task 8.3, from May to July, the INHORT (the National Institute of Horticultural Research, Poland) team carried out an experiment involving the controlled infection of the red mason bee (Osmia bicornis) with Chronic Bee Paralysis Virus (CBPV). The aim of this study was to investigate whether this virus, commonly found in the western honey bee (Apis mellifera), can be transmitted to other pollinator species and to evaluate its potential effects.

For the experiment, Osmia cocoons were placed in individual Falcon tubes and incubated for several days in a climatic chamber (see Photo 1). Newly emerged individuals were then subjected to a one-day starvation period. Subsequently, both male and female bees were individually exposed to the virus by directly feeding them a syrup solution containing the viral inoculum at four different concentrations (see Photo 2). Each individual was then placed into a cage equipped with a syringe containing sugar syrup as a food source (see Photo 3). Each group consisted of 40 bees, which together with control group sum up to 400 cages. The cages were kept in a designated room with controlled temperature and humidity following natural day-night cycles (see Photo 4). This setup allowed to maintain stable conditions and to closely monitor the behavior and health status of each bee following infection.

After collecting dead individuals, their intertegular distance will be measured as a proxy for body size, allowing to account for individual size differences in survival analyses. Preliminary observations indicate that males are considerably more susceptible to the virus than females.

Photo 1. Cocoons placed individually in Falcon tubes for emergence

Photo 2. An individual bee fed with syrup containing inoculum of CBPV

Photo 3. A cage with an individual bee

Photo 4. Bees (400 cages) placed in a room with controlled temperature and humidity

A newly published study by BEE-GUARDS partners reports the accidental introduction of the red dwarf honey bee (Apis florea) into Malta and investigates the pathogens carried by this non-native species.

The researchers found a high prevalence of Deformed Wing Virus A (DWV-A) and Nosema ceranae, together with several other important honey bee viruses. Importantly, the study highlights that these pathogens were most likely introduced together with the bees, rather than acquired after their arrival in Malta. Furthermore, the viruses were actively replicating, evidence that the bees were not simply carrying viral traces but were genuinely infected.

Why does this matter?

Islands provide a unique opportunity to study how invasive species and their pathogens interact with local pollinator communities. The study also reminds us that the movement of honey bees—intentional or accidental—can transport not only bees, but also the diseases they carry.

Continued monitoring will be essential to determine whether Apis florea becomes an established reservoir of honey bee pathogens in Malta or remains an isolated introduction.

Congratulations to the international research team on this important contribution to our understanding of honey bee health.

Read the paper here:

https://zoobank.org/5C82CFC2-4F25-43E4-B88A-1AEAE60E7420

Photo: A. Uzunov

Read even more

The following 3 studies (see links below) collectively demystify the first recorded establishment of the Asian red dwarf honey bee ( Apis florea ) in Europe. Through a systematic and stepwise approach, the core research team has assembled the pieces of this important biological puzzle, providing clarity on its establishment, and implications.

https://www.tandfonline.com/doi/full/10.1080/00218839.2024.2386888

https://www.tandfonline.com/doi/full/10.1080/0005772X.2025.2499756

https://reference-global.com/article/10.2478/jas-2026-0006

Act I – The Vanishing Site
Our researcher arrives at Site 1, monitoring equipment in hand, ready to investigate pollinator-flower interactions.
The site is… gone. Not “slightly disturbed”. Not “difficult to access”.
Completely gone.
Replaced by what appears to be a construction site in full swing. 🚧🚛
The pollinators, presumably, have relocated without leaving a forwarding address.

Act II – The Negotiation
Site 2 is still there! Great news. 🎉
Less great news: it is now home to a herd of cows, calves included…and they were not exactly welcoming.
Let’s just say our colleague had to renegotiate field access with the locals. 🐄👀
We’re choosing to interpret their attitude as unsolicited peer review.

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The reality
This is the reality of coordinated field surveys across multiple countries: biodiversity doesn’t pause for construction permits, and cows don’t read research protocols.
But the BEE-GUARDS team keeps going… adapting, problem-solving, and finding new ways to investigate how managed honey bee density affects wild pollinator communities across Europe. Because science happens in the real world. And the real world is wonderfully unpredictable. 🌍🌸

Up early morning (2nd of June) to harvest the first honey of the season. The hive scale showed a loss of 45 kg, while the actual harvest was around 35 kg — a good and promising start.

Have a look at the BeeCounter data. Honey harvesting creates a remarkable increase in activity at the hive entrance as bees react to the disturbance a honey harvest creates.

Follow the Danish online hive scale here:
https://beeguards.eu/s.html

Breaking news: during the inspection we found the beginning of a swarm cell. Ufffff.

We carried out some swarm prevention by removing the cell and adding spare frames to provide more space. The queen is only one year old, so we expect the colony to stay home, but with bees you never know.

Keep an eye on the hive scale over the coming weeks and let’s see what happens if the colony decides to challenge our expectations.

An international team of researchers, led by the first author Prof. Dr. Aleksandar Uzunov (UKIM), demonstrated that T. mercedesae mites successfully transfer into a new swarm, with some continuing to reproduce within the newly established colony. This represents the first scientific evidence of parasite transfer through swarming and moreover first evidence that male individual was transferred. The study was conducted in an apiary in Georgia with field and lab work led by Dr. Irakli Janashia and further support from Maggie Gill, Prof. D-r Chen Chao, and the BEE-GUARDS members D-r Cecilia Costa (CREA) and Prof. D-r Marin Kovacic (FAZOS).

The study “Swarming promotes Tropilaelaps mercedesae (Mesostigmata: Laelapidae) dispersal in Apis mellifera (Hymenoptera: Apidae) “ gained substantial attention, prompting Entomology Today, the publication of the Entomological Society of America, to feature an article dedicated to this important research.

For more details check the links bellow with open access articles:

https://academic.oup.com/jee/advance-article/doi/10.1093/jee/toag027/8512193?login=false

New Research Links Honey Bee Swarms to the Spread of an Invasive Mite